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Sample records for 3-4 day kelvin

  1. Climatology of the ∼5-day Rossby and ∼6-day Kelvin waves seen in the SABER/TIMED temperatures (2002-2007)

    International Nuclear Information System (INIS)

    Complete text of publication follows. The presentation is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the ∼5-day Rossby (W1) and ∼6-day Kelvin (E1) waves derived from the SABER/TIMED temperature measurements for full 6 years (January 2002-December 2007). The latitude structure of the ∼5-day W1 wave is related to the gravest symmetric wave number 1 Rossby wave, i.e. the (1,1) mode. Its seasonal behavior is dominated by equinoctial amplifications; in the NH the wave amplifies in March-April and September, while in the SH - in March and November. The vertical structure of the ∼5-day Rossby wave amplitude revealed double-peaked maxima centered at ∼80-90 km in the mesosphere and ∼105-110 km in the lower thermosphere, as the lower thermospheric maximum is at least two times stronger than the mesospheric one. This is a vertically propagating wave from the stratosphere up to 120 km altitude with a mean vertical wavelength of ∼50-60 km. The ∼5-day Rossby wave at middle latitudes (40 deg) revealed some interannual variability and at least part of it is connected with the effect of QBO. The ∼6-day E1 wave is equatorially trapped wave located between 20 deg N and 20 deg S. Its seasonal behavior indicated some equinoctial and June solstice amplifications. The altitude structure of the ∼6-day Kelvin wave phase indicated that this is a vertically propagating wave up to 110 km altitude. The mean vertical wavelength in the stratosphere and mesosphere is ∼25 km, however above 95 km altitude the vertical wavelength shortened to 15 km. The ∼6-day Kelvin wave indicated significant SAO and QBO variability.

  2. PREFACE: Kelvin and Ireland

    Science.gov (United States)

    Flood, Raymond; McCartney, Mark; Whitaker, Andrew

    2009-07-01

    Sir Joseph Larmor unveiling the Kelvin memorial in the Botanic Gardens, Belfast on a rainy day in 1913 Sir Joseph Larmor unveiling the Kelvin memorial in the Botanic Gardens, Belfast on a rainy day in 1913 © The Ulster Museum: Hogg collection William Thomson, later Lord Kelvin, was born in Belfast in 1824, and his family had lived near Ballynahinch in the north of Ireland, quite close to Belfast, from the seventeenth century. At the time of Kelvin's birth, James Thomson, his father, was Professor of Mathematics at the Belfast Royal Academical Institution (Inst). However, following the death of his wife in 1830, James took up a new position as Professor at the University of Glasgow, and he and his children moved there in 1832. Apart from three years studying at Cambridge, and a very brief period immediately afterwards travelling and teaching in Cambridge, Kelvin was to spend the rest of his life in Glasgow, where he occupied the Chair of Natural Philosophy (or Physics) for 53 years. The natural assumption might be that his birth in Ireland was irrelevant to Kelvin's life and work, and that the fine monument erected in his honour in Belfast's Botanic Gardens, which is pictured on the front cover of this volume, was more a demonstration of civic pride than a recognition of an aspect of Kelvin's life which was important to him. The purpose of the meeting was to demon strate that this was not the case, that, great Glaswegian as he undoubtedly became, Kelvin always delighted in the title of Irishman. The influence of his father, very much an Ulsterman, was immense, and Kelvin and his siblings were to follow his non-sectarian and reforming approach. Also important for Kelvin was his Christian upbringing, which began in Belfast, and his beliefs were to play a role of importance in his life and indeed in much of his most important work, in particular that on thermodynamics. Two of his siblings returned to Belfast and spent much of their lives there, and Kelvin was a

  3. From Kelvin problem to Kelvin carbons.

    Science.gov (United States)

    Zhao, Hui-Yan; Wang, Jing; Ma, Qing-Min; Liu, Ying

    2013-04-28

    As children's toys, soap bubbles also underpin many important scientific questions. What is the most efficient structure for foam? - the "Kelvin problem," has been one of the most intriguing science and widely discussed over the past hundred years. Soap bubbles' frameworks have similar topology with sp(3)-bonded carbon or silicon allotropes, e.g., Weaire-Phelan foam and superconducting clathrate Na8Si46. By looking at the most efficient structure for foams, we construct a series of new carbon allotropes, named "Kelvin carbons." Unexpectedly, all 11 Kelvin carbons are structurally stable wide-bandgap semiconductors, and their densities and their intrinsic hardnesses are both about 81%-87% that of diamond. The seventh state of Kelvin carbons, K(VII), is a very low energy carbon structure after graphite, diamond, lonsdaleite, and type-II carbon clathrate. Kelvin carbons, which constitute a "bridge" between macro-foams and micro-carbons, together with recently proposed novel carbon phases can enrich the study of carbon allotropes. PMID:23635161

  4. Leapfrogging Kelvin waves

    CERN Document Server

    Hietala, N; Salman, H; Barenghi, C F

    2016-01-01

    Two vortex rings can form a localized configuration whereby they continually pass through one another in an alternating fashion. This phenomenon is called leapfrogging. Using parameters suitable for superfluid helium-4, we describe a recurrence phenomenon that is similar to leapfrogging which occurs for two coaxial straight vortex filaments with the same Kelvin wave mode. For small amplitude Kelvin waves we demonstrate that our full Biot-Savart simulations closely follow predictions obtained from a simpified model that provides an analytical approximation developed for nearly parallel vortices. Our results are also relevant to thin-cored helical vortices in classical fluids.

  5. Lord Kelvin's atmospheric electricity measuremnets

    CERN Document Server

    Aplin, K L

    2013-01-01

    Lord Kelvin (William Thomson) made important contributions to the study of atmospheric electricity during a brief but productive period from 1859-1861. By 1859 Kelvin had recognised the need for "incessant recording" of atmospheric electrical parameters, and responded by inventing both the water-dropper instrument for measuring the atmospheric Potential Gradient (PG), and photographic data logging. The water-dropper was widely adopted internationally and is still in use today. Following theoretical considerations of electric field distortion by local topography, Kelvin developed a portable electrometer, using it to investigate PG on the Scottish island of Arran. During these environmental measurements, Kelvin may have unwittingly detected atmospheric PG changes during solar activity in August/September 1859 associated with the "Carrington event". Kelvin's atmospheric electricity work presents an early representative study in quantitative environmental physics, through the application of mathematical principle...

  6. Micro-Kelvin cold molecules.

    Energy Technology Data Exchange (ETDEWEB)

    Strecker, Kevin E.; Chandler, David W.

    2009-10-01

    We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

  7. The microfluidic Kelvin water dropper

    CERN Document Server

    Marin, Alvaro G; García-Sánchez, Pablo; Shui, Lingling; Xie, Yanbo; Fontelos, Marco A; Eijkel, Jan C T; Berg, Albert van den; Lohse, Detlef

    2013-01-01

    The so-called "Kelvin water dropper" is a simple experiment demonstrating the spontaneous appearance of induced free charge in droplets emitted through a tube. As Lord Kelvin explained, water droplets spontaneously acquire a net charge during detachment from a faucet due to the presence of electrical fields in their surrounding created by any metallic object. In his experiment, two streams of droplets are allowed to drip from separated nozzles into separated buckets, which are at the same time interconnected through the dripping needles. In this paper we build a microfluidic water dropper and demonstrate that the droplets get charged and break-up due to electrohydrodynamic instabilities. A comparison with recent simulations shows the dependence of the acquired charge in the droplets on different parameters of the system. The phenomenon opens a door to cheap and accessible transformation of pneumatic pressure into electrical energy and to an enhanced control in microfluidic and biophysical manipulation of caps...

  8. Ultrasound estimation and FE analysis of elastic modulus of Kelvin foam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nohyu; Yang, Seung Yong [School of Mechatronics Engineering, Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2016-02-15

    The elastic modulus of a 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam with 3 mm unit cell is designed and printed layer upon layer to fabricate a Kelvin foam plate of 14 mm thickness with a 3D CAD/printer using ABS plastic. The Kelvin foam plate is completely filled with paraffin wax for impedance matching, so that the acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF) method and is used to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity. Finite element method (FEM) and micromechanics is applied to the Kelvin foam plate to calculate the theoretical elastic modulus using a non-isotropic tetrakaidecahedron model. The predicted elastic modulus of the Kelvin foam plate from FEM and micromechanics model is similar, which is only 3-4% of the bulk material. The experimental value of the elastic modulus from the ultrasonic method is approximately twice as that of the numerical and theoretical methods because of the flexural deformation of the cell edges neglected in the ultrasonic method.

  9. Caustic graphene plasmons with Kelvin angle

    CERN Document Server

    Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile

    2015-01-01

    A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.

  10. Kelvin on an old, celebrated hypothesis

    Science.gov (United States)

    Harrison, Edward

    1986-07-01

    Lord Kelvin in 1901 tested an ``old and celebrated hypothesis'' that if we could see far enough into space the whole sky would be occupied with stellar disks all of perhaps the same brightness as the Sun. Kelvin was the first to solve quantitatively and correctly the riddle of a dark night sky, a riddle that had been previously solved qualitatively by Edgar Allan Poe, and is now known as Olbers' paradox.

  11. Kelvin-Helmholtz instabilities with Godunov SPH

    OpenAIRE

    Cha, Seung-Hoon; Inutsuka, Shu-Ichiro; Nayakshin, Sergei

    2009-01-01

    Numerical simulations for the non-linear development of Kelvin-Helmholtz instability in two different density layers have been performed with the particle-based method (Godunov SPH) developed by Inutsuka (2002). The Godunov SPH can describe the Kelvin-Helmholtz instability even with a high density contrast, while the standard SPH shows the absence of the instability across a density gradient (Agertz et al. 2007). The interaction of a dense blob with a hot ambient medium has been performed als...

  12. Ship wakes: Kelvin or Mach angle?

    CERN Document Server

    Rabaud, Marc

    2013-01-01

    From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as $U^{-1}$ at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of $19.47\\degree$ independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number $Fr = U/\\sqrt{gL} \\simeq 0.5$, where $L$ is the hull ship length.

  13. Kelvin wake pattern at large Froude numbers

    OpenAIRE

    Darmon, Alexandre; Benzaquen, Michael; Raphaël, Elie

    2013-01-01

    Gravity waves generated by an object moving at constant speed at the water surface form a specific pattern commonly known as the Kelvin wake. It was proved by Lord Kelvin that such a wake is delimited by a constant angle $\\simeq 19.47^\\circ$. However a recent study by Rabaud and Moisy based on the observation of airborne images showed that the wake angle seems to decrease as the Froude number $Fr$ increases, scaling as $Fr^{-1}$ for large Froude numbers. To explain such observations the autho...

  14. Ship wakes: Kelvin or Mach angle?

    Science.gov (United States)

    Rabaud, Marc; Moisy, Frédéric

    2013-05-24

    From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as U(-1) at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of 19.47° independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number Fr=U/√[gL]~/=0.5, where L is the hull ship length. PMID:23745883

  15. Kelvin's Canonical Circulation Theorem in Hall Magnetohydrodynamics

    CERN Document Server

    Shivamoggi, B K

    2016-01-01

    The purpose of this paper is to show that, thanks to the restoration of the legitimate connection between the current density and the plasma flow velocity in Hall magnetohydrodynamics (MHD), Kelvin's Circulation Theorem becomes valid in Hall MHD. The ion-flow velocity in the usual circulation integral is now replaced by the canonical ion-flow velocity.

  16. Extended Kelvin theorem in relativistic magnetohydrodynamics

    OpenAIRE

    Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We prove the existence of a generalization of Kelvin's circulation theorem in general relativity which is applicable to perfect isentropic magnetohydrodynamic flow. The argument is based on a new version of the Lagrangian for perfect magnetohydrodynamics. We illustrate the new conserved circulation with the example of a relativistic magnetohydrodynamic flow possessing three symmetries.

  17. Periodic homogenization for Kelvin-Voigt viscoelastic media with a Kelvin-Voigt viscoelastic interphase

    OpenAIRE

    Daridon, Loic; Licht, Christian; Orankitjaroen, Somsak; Pagano, Stéphane

    2016-01-01

    International audience We studied the effective behavior of a composite made of a periodic distribution of inclusions linked to a matrix by a very thin layer, with the three components being of linear Kelvin-Voigt viscoelastic type. The effective behavior, derived by a rigorous mathematical homogenization method, is not of Kelvin-Voigt type but instead involves an additional fading memory term. The influence of various parameters of the composite were numerically analyzed through a finite ...

  18. The CMS solenoid descends to 100 Kelvin

    CERN Multimedia

    Marc Favre, CERN

    2006-01-01

    After successful closing of the vacuum vessel and achievement of a good vacuum the cool-down of the CMS coil started in early February. The temperature of the coil, as of Friday February 17th, is about 100 Kelvin (-170 degrees Celsius). Members of the CERN CMI group and of Saclay stand in the vacuum vessel (from left to right): Hubert Gerwig, Francois Kircher, Benoit Cure, Domenico Campi, Bruno Levesy, Andrea Gaddi

  19. Kelvin-Helmholtz instabilities with Godunov SPH

    CERN Document Server

    Cha, Seung-Hoon; Nayakshin, Sergei

    2009-01-01

    Numerical simulations for the non-linear development of Kelvin-Helmholtz instability in two different density layers have been performed with the particle-based method (Godunov SPH) developed by Inutsuka (2002). The Godunov SPH can describe the Kelvin-Helmholtz instability even with a high density contrast, while the standard SPH shows the absence of the instability across a density gradient (Agertz et al. 2007). The interaction of a dense blob with a hot ambient medium has been performed also. The Godunov SPH describes the formation and evolution of the fingers due to the combinations of Rayleigh-Taylor, Richtmyer-Meshkov, and Kelvin-Helmholtz instabilities. The blob test result coincides well with the results of the grid-based codes. An inaccurate handling of a density gradient in the standard SPH has been pointed out as the direct reason of the absence of the instabilities. An unphysical force happens at the density gradient even in a pressure equilibrium, and repulses particles from the initial density di...

  20. Kelvin Helmholtz Instability in Planetary Magnetospheres

    Science.gov (United States)

    Johnson, Jay R.; Wing, Simon; Delamere, Peter A.

    2014-11-01

    Kelvin-Helmholtz instability plays a particularly important role in plasma transport at magnetospheric boundaries because it can control the development of a turbulent boundary layer, which governs the transport of mass, momentum, and energy across the boundary. Waves generated at the interface can also couple into body modes in the plasma sheet and inner magnetosphere where they can play an important role in plasma sheet transport and particle energization in the inner magnetosphere. Kinetic and electron-scale effects are important for the development of K-H instability, leading to secondary instabilities and plasma mixing. The development of vortices that entwine magnetosheath field lines with magnetospheric field lines also allows reconnection and the interchange of plasma blobs from open to closed field lines. Dawn-dusk asymmetries in Kelvin-Helmholtz development at planetary boundary layers may result from several effects including plasma corotation, kinetic effects, magnetic geometry, or asymmetric distribution of plasma. Examples are provided throughout the solar system illustrating the pervasive effects of the Kelvin-Helmholtz instability on plasma transport.

  1. Vertical propagation of baroclinic Kelvin waves along the west coast of India

    Indian Academy of Sciences (India)

    D Nethery; D Shankar

    2007-08-01

    A linear, continuously stratified ocean model is used to investigate vertical propagation of remotely forced, baroclinic Kelvin waves along the Indian west coast. The extent of vertical propagation over the length of the coast is found to be an increasing function of the forcing frequency. Simulations show that, over the length of the Indian west coast, vertical propagation is limited at annual and semi-annual periods, but significant at periods shorter than about 120 days. This has two major consequences. First, the depth of subsurface currents associated with these frequencies varies substantially along the coast. Second, baroclinic Kelvin waves generated in the Bay of Bengal at periods shorter than about 120 days have negligible influence on surface currents along the north Indian west coast.

  2. Equatorial atmospheric Kelvin waves during El Niño episodes and their effect on stratospheric QBO.

    Science.gov (United States)

    Das, Uma; Pan, C J

    2016-02-15

    Equatorial atmospheric Kelvin waves are investigated during a positive El Niño Southern Oscillation (ENSO) episode using temperature data retrieved from GPS Radio Occultation (RO) observations of FORMOSAT-3/COSMIC during the period from August 2006 to December 2013. Enhanced Kelvin wave amplitudes are observed during the El Niño episode of 2009-2010 and it is also observed that these amplitudes correlate with the Niño 3.4 index and also with outgoing longwave radiation and trade wind index. This study indicates that the enhanced equatorial atmospheric Kelvin wave amplitudes might be produced by geophysical processes that were involved in the onset and development of the El Niño episode. Further, easterly winds above the tropopause during this period favored the vertically upward propagation of these waves that induced a fast descending westerly regime by the end of 2010, where the zero-wind line is observed to take only 5 months to descend from 10 to 50 hPa. The current study presents observational evidence of enhanced Kelvin wave amplitudes during El Niño that has affected the stratospheric quasi-biennial oscillation (QBO) through wave-mean flow interactions. Earlier El Niño episodes of 1987 and 1998 are also qualitatively investigated, using reanalysis data. It is found that there might have been an enhancement in the equatorial Kelvin wave amplitudes during almost all El Niño episodes, however, an effect of a fast descending westerly is observed in the QBO only when the ambient zonal winds in the lower stratosphere favor the upward propagation of the Kelvin waves and consequently they interact with the mean flow. This study indicates that the El Niño and QBO are not linearly related and wave mean flow interactions play a very important role in connecting these two geophysical phenomena. PMID:26771207

  3. Radiochemistry days

    International Nuclear Information System (INIS)

    This document provides the 44 papers (transparencies used during the presentations and posters) presented at the Radiochemistry Days, held September 3-4, 1998 in Nantes, France. The main studied topics were problematic questions concerning the nuclear fuel cycle and in particular the management, storage of radioactive wastes and the environmental impact. (O.M.)

  4. CFD simulation of Kelvin-Helmholtz instability

    International Nuclear Information System (INIS)

    Kelvin-Helmholtz instability appears in stratified two-fluid flow at surface. When the relative velocity is higher than the critical relative velocity, the growth of waves occurs. The experiment of Thorpe [1] used as a benchmark in the present paper, is made in a rectangular glass tube filled with two immiscible fluids of various densities. We simulated the growth of instability with CFX-5.7 code and compared simulation with analytical solution. It was found that surface tension force, which stabilizes growth of waves, actually has a destabilizing effect in simulation, unless very small timestep and residual is used. In CFX code system of nonlinear Navier-Stokes equations is linearised and solved iterative in each timestep, until prescribed residual is achieved. On the other hand, simulation without surface tension force is more stable than analytical result predicts. (author)

  5. Ultrasonic Measurement of Elastic Modulus of Kelvin Foam

    Directory of Open Access Journals (Sweden)

    Oh Sukwon

    2016-01-01

    Full Text Available Elastic modulus of 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam of 3 mm unit cell is designed and printed layer upon layer to fablicate a Kelvin foam plate of 14mm thickness by 3D CAD/printer using ABS plastic. The Kelvin foam plate is filled completely with paraffin wax for impedance matching, so that acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF method to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity.

  6. Dust Dynamics in Kelvin-Helmholtz Instabilities

    Directory of Open Access Journals (Sweden)

    Keppens Rony

    2013-04-01

    Full Text Available The Kelvin-Helmholtz instability (KHI is a fluid instability which arises when two contacting flows have different tangential velocities. As shearing flows are very common in all sorts of (astrophysical fluid setups, the KHI is frequently encountered. In many astrophysical fluids the gas fluid in loaded with additional dust particles. Here we study the influence of these dust particles on the initiation of the KHI, as well as the effect the KHI has on the density distribution of dust species in a range of different particle sizes. This redistribution by the instability is of importance in the formation of dust structures in astrophysical fluids. To study the effect of dust on the linear and nonlinear phase of the KHI, we use the multi-fluid dust + gas module of the MPI-AMRVAC [1] code to perform 2D and 3D simulations of KHI in setups with physical quantities relevant to astrophysical fluids. A clear dependency on dust sizes is seen, with larger dust particles displaying significantly more clumping than smaller ones.

  7. Observations of Equatorial Kelvin Wave Modes in FORMOSAT-3/COSMIC GPS RO Temperature Profiles

    Directory of Open Access Journals (Sweden)

    Potula Sree Brahmanandam

    2010-01-01

    Full Text Available In this study, we analyze FORMOSAT-3/COSMIC (F3/C GPS radio occultation (RO derived temperature components for the period September 2006 to February 2008. Results show the presence of slow Kelvin waves (wave period > 10 days with higher zonal wavenumbers (either one or two in the upper troposphere and lower stratosphere (UTLS. The vertical wavelengths of these waves are found to be in the range of 5 - 12 km. The predominant Kelvin waves observed in the temperature fluctuations are in the altitude range between 15 and 28 km and centered on the tropical tropopause. The downward phase progression of these waves suggests that the derived waves are propagating upward, with the source region located at lower altitudes possibly due to tropical convective heating. The zonal winds retrieved using radiosonde observations over Singapore _ _ during this period show a periodicity of ~24 - 26 months in the stratosphere, and quasi-biennial oscillation (QBO characteristics with eastward zonal winds from March 2006 to May 2007 and westward winds from June 2007 to July 2008 respectively. Our results further show that the Kelvin wave characteristics are enhanced during the westward phase of QBO and diminish during the eastward phase, in line with the previous reported results. Furthermore, an examination of outgoing longwave radiation (OLR data shows that deep convection activity is developed episodically over the Indonesian archipelago during the observation period, thereby indicating that the Kelvin wave events observed in temperature fluctuations are either driven by convective activity (convectively coupled waves or by a broad spectrum of convective variability (free waves over the Indonesian region.

  8. A Validated Nonlinear Kelvin-Helmholtz Benchmark for Numerical Hydrodynamics

    CERN Document Server

    Lecoanet, Daniel; Quataert, Eliot; Burns, Keaton J; Vasil, Geoffrey M; Oishi, Jeffrey S; Brown, Benjamin P; Stone, James M; O'Leary, Ryan M

    2015-01-01

    The nonlinear evolution of the Kelvin-Helmholtz instability is a popular test for code verification. To date, most Kelvin-Helmholtz problems discussed in the literature are ill-posed: they do not converge to any single solution with increasing resolution. This precludes comparisons among different codes and severely limits the utility of the Kelvin-Helmholtz instability as a test problem. The lack of a reference solution has led various authors to assert the accuracy of their simulations based on ad-hoc proxies, e.g., the existence of small-scale structures. This paper proposes well-posed Kelvin-Helmholtz problems with smooth initial conditions and explicit diffusion. We show that in many cases numerical errors/noise can seed spurious small-scale structure in Kelvin-Helmholtz problems. We demonstrate convergence to a reference solution using both Athena, a Godunov code, and Dedalus, a pseudo-spectral code. Problems with constant initial density throughout the domain are relatively straightforward for both cod...

  9. A solution to the Kelvin wake angle controversy

    CERN Document Server

    Darmon, Alexandre; Raphaël, Elie

    2014-01-01

    Gravity waves generated by an object moving at constant speed at the water surface form a specific pattern commonly known as the Kelvin wake. It was proved by Lord Kelvin that such a wake is delimited by a constant angle = 19.47{\\deg}. However a recent study by Rabaud and Moisy based on the observation of airborne images showed that the wake angle seems to decrease as the Froude number Fr increases, scaling as 1/Fr for large Froude numbers. To explain such observations the authors make the strong hypothesis that an object of size b cannot generate wavelengths larger than b thus leading to unrealistic pressure fields to model the object. With no need of such an assumption, we here analytically show that the angle corresponding to the maximum amplitude of the waves scales as 1/Fr for large Froude numbers whereas the Kelvin angle remains constant for all Fr.

  10. Multi-Scale Kelvin-Helmholtz Vortices Along Mercury's Magnetopause

    Science.gov (United States)

    Gershman, D. J.; Raines, J. M.; Slavin, J. A.; Zurbuchen, T.; Sundberg, T.; Boardsen, S. A.; Anderson, B. J.; Korth, H.; Solomon, S. C.

    2014-12-01

    Data from the Fast Imaging Plasma Spectrometer (FIPS) and Magnetometer (MAG) sensors on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft have revealed stark differences in the Kelvin-Helmholtz (K-H) instability at Mercury compared with that at Earth. Although K-H vortices have been documented in planetary magnetospheres at the interface of magnetosheath and magnetospheric plasmas, such features at Mercury have been observed exclusively on the dusk side. From a survey of 58 K-H events, we find that these vortices have two distinct sets of behavior separated by the dusk terminator. On the dayside, the wave frequencies measured by MAG are nearly constant at ~0.025 Hz (~40 s period) under a variety of magnetosheath conditions, whereas the wave frequency measured on the nightside is correlated with the strength of the magnetic field near the magnetopause and matches the local Na+ gyrofrequency. The polarization of these waves inside the magnetosphere is distinctly right-handed, consistent with non-linear roll-up of K-H vortices as opposed to the left-handed ion-cyclotron wave mode. During these events, measurements from FIPS reveal strong (~30%) concentrations of Na+ in the nightside plasma sheet adjacent to the magnetopause. The keV energies of these planetary ions provide them with gyroradii that are ~500-1000 km, a scale at which a kinetic description of the K-H instability may be appropriate at Mercury. These data suggest a transition from fluid-scale to kinetic scale K-H vortices from day to night along Mercury's duskside magnetopause.

  11. Nuclear order in silver at pico-Kelvin temperature

    DEFF Research Database (Denmark)

    Siemensmeyer, K.; Clausen, K.N.; Lefmann, K.;

    1997-01-01

    Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 μT. The entropy-field phase diagram was determined using the spin-dependent absorption.......Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 μT. The entropy-field phase diagram was determined using the spin-dependent absorption....

  12. Nuclear order in silver at pico-Kelvin temperature

    DEFF Research Database (Denmark)

    Siemensmeyer, K.; Clausen, K.N.; Lefmann, K.;

    1997-01-01

    Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 mu T. The entropy-field phase diagram was determined using the spin-dependent absorption.......Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 mu T. The entropy-field phase diagram was determined using the spin-dependent absorption....

  13. Temperature Scales: Celsius, Fahrenheit, Kelvin, Reamur, and Romer.

    Science.gov (United States)

    Romer, Robert H.

    1982-01-01

    Traces the history and development of temperature scales which began with the 17th-century invention of the liquid-in-glass thermometer. Focuses on the work of Olaf Romer, Daniel Fahrenheit, Rene-Antoine de Reamur, Anders Celsius, and William Thomson (Lord Kelvin). Includes experimental work and consideration of high/low fixed points on the…

  14. Kelvin-Helmholtz and Buckling Instabilities for a Viscoelastic Liquid

    CERN Document Server

    Keshavarz, Bavand

    2012-01-01

    In this fluid dynamics video prepared for the APS-DFD Gallery of Fluid Motion we study the Kelvin-Helmholtz instability for both Newtonian and viscoelastic jets. The nonlinear dynamics of the jet motion are slowed down by orders of magnitude using a synchronized strobe effect coupled with precise timing control of perturbation frequencies. Our results show that at high wave-numbers the imposed perturbations initially grow linearly with time and the jet axis remains straight while the Kelvin-Helmholtz wave amplitude grows and rolls up into bags that encapsulate the central jet within themselves. At low wave-numbers (long wave-lengths) the jet axis buckles under the action of viscous stresses and a coupling between the Kelvin-Helmholtz instability and bending of the jet leads to new concertina or chevron modes which grow with time as they move downstream. Addition of viscoelasticity to the jet leads to the pronounced inhibition of the Kelvin-Helmholtz instability as the jet perturbation amplitude grows and larg...

  15. Kelvin principle for a class of singular equations

    Directory of Open Access Journals (Sweden)

    Abdullah Altin

    1989-01-01

    Full Text Available The classical Kelvin principle concerns invariance of solutions of the Laplace equation with respect to inversion in a sphere. By employing a hyperbolic-polar coordinate system, the principle is extended to cover a class of singular equations, which include the ultrahyperbolic equation.

  16. On the absence of appreciable half-life changes in alpha emitters cooled in metals to 1 Kelvin and below

    CERN Document Server

    Stone, N J; Richards, P; Stone, J R; Veskovic, M; Williams, D A

    2006-01-01

    The recent suggestion that dramatic changes may occur in the lifetime of alpha and beta decay when the activity, in a pure metal host, is cooled to a few Kelvin, is examined in the light of published low temperature nuclear orientation (LTNO) experiments, with emphasis here on alpha decay. In LTNO observations are made of the anisotropy of radioactive emissions with respect to an axis of orientation. Correction of data for decay of metallic samples held at temperatures at and below 1 Kelvin for periods of days and longer has been a routine element of LTNO experiments for many years. No evidence for any change of half life on cooling, with an upper level of less than 1%, has been found, in striking contrast to the predicted changes, for alpha decay, of several orders of magnitude. The proposal that such dramatic changes might alleviate problems of disposal of long-lived radioactive waste is shown to be unrealistic.

  17. 38 CFR 3.4 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Compensation. 3.4 Section..., Compensation, and Dependency and Indemnity Compensation General § 3.4 Compensation. (a) Compensation. This term...) Disability compensation. (1) Basic entitlement for a veteran exists if the veteran is disabled as the...

  18. Kelvin Waves and Dynamic Knots on Perturbative Helical Vortex Lines

    CERN Document Server

    Kou, Su-Peng

    2016-01-01

    Vortex lines are one-dimensional extended objects in three-dimensional superfluids. Vortex lines have many interesting properties, including Kelvin waves, exotic statistics, and possible entanglement. In this paper, an emergent "quantum world" is explored by projecting helical vortex lines. A one-dimensional quantum Fermionic model is developed to effectively describe the local fluctuations of helical vortex lines. The elementary excitations are knots with half winding-number that obey emergent quantum mechanics. The Biot-Savart equation, and its Kelvin wave solutions on helical vortex lines become Schrodinger equation, and the wave functions of probability waves for finding knots, respectively. This work shows an alternative approach to simulating quantum many-body physics based on classical systems.

  19. Kelvin-Helmholtz instabilities in tokamak edge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Garbet, X.; Fenzi, C.; Capes, H.; Devynck, P.; Antar, G

    1999-07-15

    The parallel Kelvin-Helmholtz instability is investigated as a possible explanation for poloidal asymmetries of density fluctuations which reverse with the plasma current direction. It is shown that these modes are localised around the position where the radial gradient of parallel velocity is maximum. Two mechanisms lead to unstable Kelvin-Helmholtz modes: the acceleration of ions in a presheath and the anomalous Stringer spin-up due to asymmetries of the particle flux. Up-down asymmetries are explained by combining these two effects. Depending on the limiter configuration, the Stringer effect amplifies or weakens the flow due to presheath acceleration. This type of asymmetry reverses with the plasma current direction. (authors)

  20. Dense magnetospheric plasma and Kelvin-Helmholtz waves

    Science.gov (United States)

    Walsh, B.

    2015-12-01

    The coupling of energy between the solar wind and a planetary magnetosphere is a function of the plasma parameters on both sides of the planet's magnetopause. Scientists routinely monitor the changing conditions in the solar wind in efforts to predict the dynamics at the magnetopause, but there can also be significant changes within the magnetosphere that play a role. On the magnetospheric side, the plasma density can change by several orders of magnitude (0.1cm-3 to 50cm-3). The current study investigates the role of dense magnetospheric plasma in the formation of Kelvin-Helmholtz waves at the magnetopause boundary. Spacecraft observations and SuperDARN radar measurements are presented showing the occurrence of Kelvin-Helmholtz waves on the dayside magnetopause under relatively low shear flows in the presence of a dense plasmaspheric plume.

  1. Kelvin-Helmholtz wave generation beneath hovercraft skirts

    Science.gov (United States)

    Sullivan, P. A.; Walsh, C.; Hinchey, M. J.

    1993-05-01

    When a hovercraft is hovering over water, the air flow beneath its skirts can interact with the water surface and generate waves. These, in turn, can cause the hovercraft to undergo violent self-excited heave motions. This note shows that the wave generation is due to the classical Kelvin-Helmholtz mechanism where, beyond a certain air flow rate, small waves at the air water interface extract energy from the air stream and grow.

  2. 3,4-methylenedioxymethamphetamine (MDMA: current perspectives

    Directory of Open Access Journals (Sweden)

    Meyer JS

    2013-11-01

    Full Text Available Jerrold S Meyer Department of Psychology, Neuroscience and Behavior Program, University of Massachusetts, Amherst, MA, USA Abstract: Ecstasy is a widely used recreational drug that usually consists primarily of 3,4-methylenedioxymethamphetamine (MDMA. Most ecstasy users consume other substances as well, which complicates the interpretation of research in this field. The positively rated effects of MDMA consumption include euphoria, arousal, enhanced mood, increased sociability, and heightened perceptions; some common adverse reactions are nausea, headache, tachycardia, bruxism, and trismus. Lowering of mood is an aftereffect that is sometimes reported from 2 to 5 days after a session of ecstasy use. The acute effects of MDMA in ecstasy users have been attributed primarily to increased release and inhibited reuptake of serotonin (5-HT and norepinephrine, along with possible release of the neuropeptide oxytocin. Repeated or high-dose MDMA/ecstasy use has been associated with tolerance, depressive symptomatology, and persisting cognitive deficits, particularly in memory tests. Animal studies have demonstrated that high doses of MDMA can lead to long-term decreases in forebrain 5-HT concentrations, tryptophan hydroxylase activity, serotonin transporter (SERT expression, and visualization of axons immunoreactive for 5-HT or SERT. These neurotoxic effects may reflect either a drug-induced degeneration of serotonergic fibers or a long-lasting downregulation in 5-HT and SERT biosynthesis. Possible neurotoxicity in heavy ecstasy users has been revealed by neuroimaging studies showing reduced SERT binding and increased 5-HT2A receptor binding in several cortical and/or subcortical areas. MDMA overdose or use with certain other drugs can also cause severe morbidity and even death. Repeated use of MDMA may lead to dose escalation and the development of dependence, although such dependence is usually not as profound as is seen with many other drugs of abuse

  3. A Review Paper: Contributions from the Gravity and the Kelvin Modes for the Vertical Motion Response.

    Directory of Open Access Journals (Sweden)

    Julio Buchmann

    2009-10-01

    Full Text Available In earlier papers of a series of real data integrations of the National Center for Atmospheric Research (NCAR Community Climate Model (CCM with tropical heat anomalies display regions of pronounced subsidence and drying located several thousand kilometers westward poleward of the heating for cases of tropical Atlantic heating and tropical east Pacific heating. This highly predictable sinking response is established within the first five days of these integrations. The normal-modes of a set of nonlinear primitive equations for an atmosphere: Adiabatic, hydrostatic, incompressible, dry, without friction and viscosity are linearized about a basic state at rest and used to partition model response into gravity-inertia and Rossby modes. The emphasis of this review is given upon the contributions of the gravity and Kelvin modes for the vertical motion response.

  4. Noise performance of frequency modulation Kelvin force microscopy

    Directory of Open Access Journals (Sweden)

    Heinrich Diesinger

    2014-01-01

    Full Text Available Noise performance of a phase-locked loop (PLL based frequency modulation Kelvin force microscope (FM-KFM is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values.

  5. Kelvin-Helmholtz instabilities with Godunov smoothed particle hydrodynamics

    Science.gov (United States)

    Cha, Seung-Hoon; Inutsuka, Shu-Ichiro; Nayakshin, Sergei

    2010-04-01

    Numerical simulations for the non-linear development of Kelvin-Helmholtz instability in two different density layers have been performed with the particle-based method (Godunov SPH) developed by Inutsuka. The Godunov SPH can describe the Kelvin-Helmholtz instability even with a high-density contrast, while the standard SPH shows the absence of the instability across a density gradient. The interaction of a dense blob with a hot ambient medium has been performed also. The Godunov SPH describes the formation and evolution of the fingers due to the combinations of Rayleigh-Taylor, Richtmyer-Meshkov and Kelvin-Helmholtz instabilities. The blob test result coincides well with the results of the grid-based codes. An inaccurate handling of a density gradient in the standard SPH has been pointed out as the direct reason of the absence of the instabilities. An unphysical force happens at the density gradient even in a pressure equilibrium, and repulses particles from the initial density discontinuity. Therefore, the initial perturbation damps, and a gap form at the discontinuity. The unphysical force has been studied in terms of the consistency of a numerical scheme. Contrary to the standard SPH, the momentum equation of the Godunov SPH does not use the particle approximation, and has been derived from the kernel convolution or a new Lagrangian function. The new Lagrangian function used in the Godunov SPH is more analogous to the real Lagrangian function for continuum. The momentum equation of the Godunov SPH has much better linear consistency, so the unphysical force is greatly reduced compared to the standard SPH in a high density contrast.

  6. The metabolite 3,4,3',4'-tetrachloroazobenzene (TCAB) exerts a higher ecotoxicity than the parent compounds 3,4-dichloroaniline (3,4-DCA) and propanil.

    Science.gov (United States)

    Xiao, Hongxia; Kuckelkorn, Jochen; Nüßer, Leonie Katharina; Floehr, Tilman; Hennig, Michael Patrick; Roß-Nickoll, Martina; Schäffer, Andreas; Hollert, Henner

    2016-05-01

    3,4,3',4'-tetrachloroazobenzene (TCAB) is not commercially manufactured but formed as an unwanted by-product in the manufacturing of 3,4-dichloroaniline (3,4-DCA) or metabolized from the degradation of chloranilide herbicides, like propanil. While a considerable amount of research has been done concerning the toxicological and ecotoxicological effects of propanil and 3,4-DCA, limited information is available on TCAB. Our study examined the toxicity of TCAB in comparison to its parent compounds propanil and 3,4-DCA, using a battery of bioassays including in vitro with aryl hydrocarbon receptor (AhR) mediated activity by the 7-ethoxyresorufin-O-deethylase (EROD) assay and micro-EROD, endocrine-disrupting activity with chemically activated luciferase gene expression (CALUX) as well as in vivo with fish embryo toxicity (FET) assays with Danio rerio. Moreover, the quantitative structure activity response (QSAR) concepts were applied to simulate the binding affinity of TCAB to certain human receptors. It was shown that TCAB has a strong binding affinity to the AhR in EROD and micro-EROD induction assay, with the toxic equivalency factor (TEF) of 8.7×10(-4) and 1.2×10(-5), respectively. TCAB presented to be a weak endocrine disrupting compound with a value of estradiol equivalence factor (EEF) of 6.4×10(-9) and dihydrotestosterone equivalency factor (DEF) of 1.1×10(-10). No acute lethal effects of TCAB were discovered in FET test after 96h of exposure. Major sub-lethal effects detected were heart oedema, yolk malformation, as well as absence of blood flow and tail deformation. QSAR modelling suggested an elevated risk to environment, particularly with respect to binding to the AhR. An adverse effect potentially triggering ERβ, mineralocorticoid, glucocorticoid and progesterone receptor activities might be expected. Altogether, the results obtained suggest that TCAB exerts a higher toxicity than both propanil and 3,4-DCA. This should be considered when assessing the

  7. Kelvin-Helmholtz instability and vortices in magnetized plasma

    International Nuclear Information System (INIS)

    Analytic theory and implicit particle simulations are used to describe the evolution of the Kelvin-Helmholtz instability and the plasma vortices driven by a nonuniform E x B flow velocity. Formulas for plasma convection arising from the self-consistent plasma electric field give the rate of anomalous momentum transport across the magnetic field. The momentum transport is shown to be controlled by the tilting angle of the elliptical vortex with respect to the direction of the parallel flow. Three stages of evolution are investigated and formulas for the final vortex state are given

  8. Strain analysis of nonlocal viscoelastic Kelvin bar in tension

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xue-chuan; LEI Yong-jun; ZHOU Jian-ping

    2008-01-01

    Based on viscoelastic Kelvin model and nonlocal relationship of strain and stress, a nonlocal constitutive relationship of viscoelasticity is obtained and the strain response of a bar in tension is studied. By transforming governing equation of the strain analysis into Volterra integration form and by choosing a symmetric exponential form of kernel function and adapting Neumann series, the closed-form solution of strain field of the bar is obtained. The creep process of the bar is presented. When time approaches infinite, the strain of bar is equal to the one of nonlocal elasticity.

  9. Momentum Transport and Stable Modes in Kelvin-Helmholtz Turbulence

    CERN Document Server

    Fraser, A E; Zweibel, E G

    2016-01-01

    The Kelvin-Helmholtz (KH) instability, which arises in astrophysical and fusion systems where turbulent momentum transport is important, has an unstable and a stable mode at the same scales. We show that in KH turbulence, as in other types of turbulence, the stable mode affects transport, nonlinearly removing energy from the inertial-range cascade to small scales. We quantify energy transfer to stable modes and its associated impact on turbulent amplitudes and transport, demonstrating that stable modes regulate transfer in KH systems. A quasilinear momentum transport calculation is performed to quantify the reduction in momentum transport due to stable modes.

  10. Magnetic moments of lanthanide 3-, 4-nitrobenzoates and 3,4-dinitrobenzoates

    International Nuclear Information System (INIS)

    The magnetic moments for lanthanide 3-nitro and 4-nitrobenzoates were determined at 298 K and those for 3,4-dinitrobenzoates of rare earth elements over the temperature range 77 - 296 K. The complexes of 3,4-dinitrobenzoates of rare earth were found to obey the Curie-Weiss law. The values of μ calculated for all complexes (except that for europium 3,4-dinitrobenzoates) are close to those obtained for Ln3+ ions by Hund and Van Vleck. The results reveal that irrespective of the kind of ligands (3-nitro, 4-nitro or 3,4-dinitrobenzoates) no influence of their field on lanthanide ions occurs. (author)

  11. Kelvin-Helmholtz instability of a coronal streamer

    CERN Document Server

    Feng, Li; Gan, Weiqun

    2013-01-01

    The shear-flow-driven instability can play an important role in energy transfer processes in coronal plasma. We present for the first time the observation of a kink-like oscillation of a streamer probably caused by the streaming kinkmode Kelvin-Helmholtz instability. The wave-like behavior of the streamer was observed by Large Angle and Spectrometric Coronagraph Experiment (LASCO) C2 and C3 aboard SOlar and Heliospheric Observatory (SOHO). The observed wave had a period of about 70 to 80 minutes, and its wavelength increased from 2 Rsun to 3 Rsun in about 1.5 hours. The phase speeds of its crests and troughs decreased from 406 \\pm 20 to 356 \\pm 31kms^{-1} during the event. Within the same heliocentric range, the wave amplitude also appeared to increase with time. We attribute the phenomena to the MHD Kelvin-Helmholtz instability which occur at a neutral sheet in a fluid wake. The free energy driving the instability is supplied by the sheared flow and sheared magnetic field across the streamer plane. The plasm...

  12. Coastal Kelvin waves and dynamics of Gulf of Aden eddies

    Science.gov (United States)

    Valsala, Vinu K.; Rao, Rokkam R.

    2016-10-01

    The Gulf of Aden (GA) is a small semi-enclosed oceanic region between the Red Sea and the western Arabian Sea. The GA is characterised with westward propagating cyclonic and anti-cyclonic eddies throughout the year. The genesis and propagation of these eddies into the GA have been the focus of several studies which concluded that oceanic instabilities (both barotropic and baroclinic) as well as the Rossby waves from the Arabian Sea are the responsible mechanisms for the presence and maintenance of these eddies. Using a high-resolution (~11 km) reduced gravity hydrodynamic layered model with controlled lateral boundary conditions at the three sides of the GA here we show yet another factor, the coastally propagating Kelvin waves along the coastal Arabia (coasts of Oman and Yemen), is also critically important in setting up a favourable condition for the oceanic instabilities and sustenance of meso-scale eddies in the GA. These Kelvin waves at both seasonal and intra-seasonal time scales are found play an important role in the timing and amplitudes of eddies observed in the GA.

  13. 3,4-methylenedioxymethamphetamine (MDMA): current perspectives

    OpenAIRE

    Meyer JS

    2013-01-01

    Jerrold S Meyer Department of Psychology, Neuroscience and Behavior Program, University of Massachusetts, Amherst, MA, USA Abstract: Ecstasy is a widely used recreational drug that usually consists primarily of 3,4-methylenedioxymethamphetamine (MDMA). Most ecstasy users consume other substances as well, which complicates the interpretation of research in this field. The positively rated effects of MDMA consumption include euphoria, arousal, enhanced mood, increased sociability, and heighten...

  14. Kelvin--Helmholtz instability in an active region jet observed with \\emph{Hinode}

    CERN Document Server

    Zhelyazkov, I; Srivastava, A K

    2015-01-01

    Over past ten years a variety of jet-like phenomena were detected in the solar atmosphere, including plasma ejections over a range of coronal temperatures being observed as extreme ultraviolet (EUV) and X-ray jets. We study the possibility for the development of Kelvin--Helmholtz (KH) instability of transverse magnetohydrodynamic (MHD) waves traveling along an EUV jet situated on the west side of NOAA AR 10938 and observed by three instruments on board Hinode on 2007 January 15/16 (Chifor et al., Astron. Astrophys.481, L57 (2008)). The jet was observed around LogT_e = 6.2 with up-flow velocities exceeded 150 km/s. Using Fe XII lambda186 and lambda195 line ratios, the measured densities were found to be above LogN_e = 11. We have modeled that EUV jet as a vertically moving magnetic flux tube (untwisted and weakly twisted) and have studied the propagation characteristics of the kink (m=1) mode and the higher m modes with azimuthal mode numbers m=2,3,4. It turns out that all these MHD waves can become unstable a...

  15. Simulation of Kelvin-Helmholtz Instability with Flux-Corrected Transport Method

    Institute of Scientific and Technical Information of China (English)

    WANG Li-Feng; YE Wen-Hua; FAN Zheng-Feng; LI Ying-Jun

    2009-01-01

    The sixth-order accurate phase error flux-corrected transport numerical algorithm is introduced, and used to simulate Kelvin-Helmholtz instability. Linear growth rates of the simulation agree with the linear theories of Kelvin-Helmholtz instability. It indicates the validity and accuracy of this simulation method. The method also has good capturing ability of the instability interface deformation.

  16. The Lord Kelvin Project: Middle School Science for the 21st Century.

    Science.gov (United States)

    Foti, Sebastian; Ledbetter, Ric; Taylor, Fred; Al-Kazemi, Ebraheem

    This paper introduces and reports upon lessons learned during the development phase of the Lord Kelvin Middle School Science Program. For the past two years, a set of tools to help middle school students learn science in a way that uses the full power of today's technology has been under development. Lord Kelvin is a robust collection of science…

  17. Erratum: SDO-AIA Observation of Kelvin-helmholtz Instability in the Solar Corona

    Science.gov (United States)

    Ofman, Leon; Thompson, Barbara J.

    2012-01-01

    The first SDOAIA observation of the KelvinHelmholtz instability in the solar corona in the 2010 April 8 event was reported by Ofman Thompson (2010, 2011). Foullon et al. (2011), which was published prior to Ofman Thompson (2011), claimed the detection of the KelvinHelmholtz instability in a later event (2010 November 3), and should have been cited in Ofman Thompson (2011).

  18. Flow estimation for the Persian Gulf using a Kelvin wave expansion

    NARCIS (Netherlands)

    Badri, M.A.; Wilders, P.; Azimian, A.R.

    2010-01-01

    Hydrodynamic simulations of tidal currents in the Persian Gulf are presented. Water surface level and velocity have been determined by a Kelvin wave expansion as a new hydrodynamic calibration tool for estimating the dynamical field and flow patterns. In the procedure, leading to the Kelvin wave exp

  19. Sleeping body temperatures in 3-4 month old infants.

    OpenAIRE

    Wailoo, M P; Petersen, S A; Whittaker, H.; Goodenough, P

    1989-01-01

    Rectal, skin, and ambient temperatures were continuously recorded overnight from 3-4 month old normal infants in their home cots under conditions of room temperature and wrapping chosen freely by parents. It was found that rectal temperature was above 37 degrees C when infants were put down, but fell rapidly to 36.4 degrees C within one and a half hours, then stabilised for a few hours before rising steadily. This pattern was tied more closely to the time of putting down than time of day. The...

  20. Kelvin Probe Studies of Cesium Telluride Photocathode for AWA Photoinjector

    CERN Document Server

    Wisniewski, Eric; Yusof, Zikri; Spentzouris, Linda; Terry, Jeff; Harkay, Katherine

    2012-01-01

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (~50 nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  1. Analysis and simulation of the operation of a Kelvin probe

    CERN Document Server

    Reasenberg, Robert D; Phillips, James D

    2013-01-01

    Experiments that measure extremely small gravitational forces are often hampered by the presence of non-gravitational forces that can neither be calculated nor separately measured. Among these spurious forces is electrostatic attraction between a test mass and its surroundings due to the presence of spatially varying surface potential known as the "patch effect." In order to make surfaces with small surface potential variation, it is necessary to be able to measure it. A Kelvin probe (KP) measures contact potential difference (CPD), using the time-varying capacitance between the sample and a vibrating tip that is biased with a backing potential. Assuming that the tip remains constant, this measures the sample's surface potential variation. We examine the operation of the KP from the perspective of parameter estimation in the presence of noise. We show that, when the CPD is estimated from measurements at two separate backing potentials, the standard deviation of the optimal estimate depends on the total observ...

  2. Radiochemistry days; Journees radiochimie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This document provides the 44 papers (transparencies used during the presentations and posters) presented at the Radiochemistry Days, held September 3-4, 1998 in Nantes, France. The main studied topics were problematic questions concerning the nuclear fuel cycle and in particular the management, storage of radioactive wastes and the environmental impact. (O.M.)

  3. 3, 4-methylenedioximethamphetamin reverses anxiety induced by chronic mild stress

    Directory of Open Access Journals (Sweden)

    Laura Andrea León A

    2013-01-01

    Full Text Available Here we report the effects of subchronic 3, 4 methylenedioximethamphetamine (MDMA on the elevated plusmaze, a widely used animal model of anxiety. Rats exposed to a mild chronic stress (MCS protocol received intracerebroventricular microinjections of the selective serotonin reuptake inhibitor (SSRI – fluoxetine (2.0 ug/ul or MDMA, (2.0 ug/ul for seven days. On the eighth day rats were tested in the elevated plus-maze. Our results showed that sub chronic MDMA interacted with MCS leading to a decrease in anxiety related behaviors including: percentage of open arms entries (F [2, 26] = 4.00; p = 0.031, time spent in the open arms (F [2, 26] = 3.656; p = 0.040 and time spent in the open arms extremities (F [2, 26] = 5.842; p = 0.008. These results suggest a potential effect of MDMA in the reversion of the emotional significance of aversive stimuli.

  4. 29 CFR 3.4 - Submission of weekly statements and the preservation and inspection of weekly payroll records.

    Science.gov (United States)

    2010-07-01

    ... inspection of weekly payroll records. 3.4 Section 3.4 Labor Office of the Secretary of Labor CONTRACTORS AND... STATES § 3.4 Submission of weekly statements and the preservation and inspection of weekly payroll... subcontractor, within seven days after the regular payment date of the payroll period, to a representative of...

  5. Specific heats of lunar surface materials from 90 to 350 degrees Kelvin

    Science.gov (United States)

    Robie, R.A.; Hemingway, B.S.; Wilson, W.H.

    1970-01-01

    The specific heats of lunar samples 10057 and 10084 returned by the Apollo 11 mission have been measured between 90 and 350 degrees Kelvin by use of an adiabatic calorimeter. The samples are representative of type A vesicular basalt-like rocks and of finely divided lunar soil. The specific heat of these materials changes smoothly from about 0.06 calorie per gram per degree at 90 degrees Kelvin to about 0.2 calorie per gram per degree at 350 degrees Kelvin. The thermal parameter ??=(k??C)-1/2 for the lunar surface will accordingly vary by a factor of about 2 between lunar noon and midnight.

  6. May Day

    Institute of Scientific and Technical Information of China (English)

    王芳

    2009-01-01

    For Teacher: May Day occurs in May 1 and refers to any of several public holidays.In many countries, May Day is synonymous(同义词的)with International Workers' Day, or Labor Day, which celebrates the social and economic achievements(成就)of the labor movement.

  7. May Day

    Institute of Scientific and Technical Information of China (English)

    王芳

    2009-01-01

    For Teachers: May Day occurs on May 1 and refers to any of several public holidays. In many coun- tries, May Day is synonymous (同义词的) with International Workers' Day, or Labor Day, which celebrates the social and economic achievements (成就) of the labor movement. As a day of celebration, the holiday has an- cient origins (起源), and it can relate to many customs that have survived into modem times.

  8. Vertical propagation of baroclinic Kelvin waves along the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nethery, D.; Shankar, D.

    , this paper is intended to provide the motivation for studying the vertical propagation of coastal Kelvin waves with a general circulation model, allowing the influence of density variations, basin geometry, and mixing processes to be examined...

  9. Mathematical justification of Kelvin-Voigt beam models by asymptotic methods

    Science.gov (United States)

    Rodríguez-Arós, Á. D.; Viaño, J. M.

    2012-06-01

    The authors derive and justify two models for the bending-stretching of a viscoelastic rod by using the asymptotic expansion method. The material behaviour is modelled by using a general Kelvin-Voigt constitutive law.

  10. Direct evidence of Kelvin waves in numerical simulations of quantum turbulence

    CERN Document Server

    di Leoni, Patricio Clark; Brachet, Marc E

    2015-01-01

    We present direct evidence of Kelvin waves in space-time resolved spectra of numerical simulations of quantum turbulence. Kelvin waves are transverse and circularly polarized waves that propagate along quantized vortices, for which the restitutive force is the tension of the vortex line, and which play an important role in theories of superfluid turbulence. We use the Gross-Pitaevskii equation to model quantum flows, letting an initial array of well-organized vortices develop into a turbulent bundle of intertwined vortex filaments. By achieving high spatial and temporal resolution we are able to calculate space-time resolved mass density and kinetic energy spectra. Evidence of Kelvin and sound waves is clear in both spectra. Identification of the waves allows us to extract the spatial spectrum of Kelvin waves, clarifying their role in the transfer of energy.

  11. KELVIN-HELMHOLTZ INSTABILITY OF A CORONAL STREAMER

    Energy Technology Data Exchange (ETDEWEB)

    Feng, L.; Gan, W. Q. [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 210008 Nanjing (China); Inhester, B., E-mail: lfeng@pmo.ac.cn [Max-Planck-Institut fuer Sonnensystemforschung, Max-Planck-Str.2, D-37191 Katlenburg-Lindau (Germany)

    2013-09-10

    Shear-flow-driven instability can play an important role in energy transfer processes in coronal plasma. We present for the first time the observation of a kink-like oscillation of a streamer that is probably caused by the streaming kink-mode Kelvin-Helmholtz instability (KHI). The wave-like behavior of the streamer was observed by the Large Angle and Spectrometric Coronagraph Experiment C2 and C3 on board the SOlar and Heliospheric Observatory. The observed wave had a period of about 70-80 minutes, and its wavelength increased from 2 R{sub Sun} to 3 R{sub Sun} in about 1.5 hr. The phase speeds of its crests and troughs decreased from 406 {+-} 20 to 356 {+-} 31 km s{sup -1} during the event. Within the same heliocentric range, the wave amplitude also appeared to increase with time. We attribute the phenomena to the MHD KHI, which occurs at a neutral sheet in a fluid wake. The free energy driving the instability is supplied by the sheared flow and sheared magnetic field across the streamer plane. The plasma properties of the local environment of the streamer were estimated from the phase speed and instability threshold criteria.

  12. Interactions between two magnetohydrodynamic Kelvin-Helmholtz instabilities.

    Science.gov (United States)

    Lai, S H; Ip, W-H

    2011-10-01

    Kelvin-Helmholtz instability (KHI) driven by velocity shear is a generator of waves found away from the vicinity of the velocity-shear layers since the fast-mode waves radiated from the surface perturbation can propagate away from the transition layer. Thus the nonlinear evolution associated with KHI is not confined near the velocity-shear layer. To understand the physical processes in multiple velocity-shear layers, the interactions between two KHIs at a pair of tangential discontinuities are studied by two-dimensional magnetohydrodynamic simulations. It is shown that the interactions between two neighboring velocity-shear layers are dominated by the propagation of the fast-mode waves radiated from KHIs in a nonuniform medium. That is, the fast-mode Mach number of the surface waves M(Fy), a key factor of the nonlinear evolution of KHI, will vary with the nonuniform background plasma velocity due to the existence of two neighboring velocity-shear layers. As long as the M(Fy) observed in the plasma rest frame across the neighboring velocity-shear layer is larger than one, newly formed fast-mode Mach-cone-like (MCL) plane waves generated by the fast-mode waves can be found in this region. As results of the interactions of two KHIs, reflection and distortion of the MCL plane waves generate the turbulence and increase the plasma temperature, which provide possible mechanisms of heating and accelerating local plasma between two neighboring velocity-shear layers.

  13. Kelvin probe studies of cesium telluride photocathode for AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, Eric E., E-mail: ewisniew@anl.gov [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Velazquez, Daniel [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Yusof, Zikri, E-mail: zyusof@hawk.iit.edu [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Spentzouris, Linda; Terry, Jeff [Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Sarkar, Tapash J. [Rice University, 6100 Main, Houston, TX 77005 (United States); Harkay, Katherine [Accelerator Science Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States)

    2013-05-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (≈50nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating. -- Highlights: ► The correlation between Quantum Efficiency (QE) and work function. ► How QE and work function evolve together. ► Rejuvenation of the photocathode via heating and the effect on work function. ► The effects on the work function due to exposure to UV light.

  14. Kelvin-Helmholtz Instability in Compressible Flows and Mixing Inhibition

    Science.gov (United States)

    Karimi, Mona; Girimaji, Shararath

    2015-11-01

    It is well-established that the Kelvin-Helmholtz (KH) instability is central to shear flow mixing. Toward understanding the suppression of turbulent mixing under the influence of compressibility, we first examine the modification to KH instability in a planar mixing layer at high speeds. In this presentation, combining the outcomes of the linear stability analysis with the results of the numerical simulation, we establish that the flow domain can be classified into two main regions: the outer regions on the fast and slow sides and dilatational interface layer (DIL) in the middle. Compressibility engenders the formation of a dilatational or acoustic layer at the high-shear interface between two streams of different speeds. Within the DIL, the velocity perturbations become oscillatory. In the incompressible shear layers, the interface experiences steady vortical motion that entrains fluid from both streams leading to familiar KH behavior. In contrast, in the compressible case, the interface motion is oscillatory inhibiting vortex-merging and roll-up, thereby suppressing entrainment that leads to inhibition of the KH instability. Analysis and illustrations of the constituent mechanisms are presented.

  15. Kelvin--Helmholtz instability in solar H-alpha surges

    CERN Document Server

    Zhelyazkov, I; Chandra, R; Srivastava, A K; Mishonov, T

    2015-01-01

    We study the evolutionary conditions for Kelvin--Helmholtz (KH) instability in a H-alpha solar surge observed in NOAA AR 8227 on 1998 May 30. The jet with speeds in the range of 45--50 km/s, width of 7 Mm, and electron number density of 3.83 x 10^{10} cm^{-3} is assumed to be confined in a twisted magnetic flux tube embedded in a magnetic field of 7 G. The temperature of the plasma flow is of the order of 10^5 K while that of its environment is taken to be 2 x 10^6 K. The electron number density of surrounding magnetized plasma has a typical for the TR/lower corona region value of 2 x 10^{9} cm^{-3}. Under these conditions, the Alfven speed inside the jet is equal to 78.3 km/s. We model the surge as a moving magnetic flux tube for two magnetic field configurations: (i) a twisted tube surrounded by plasma with homogeneous background magnetic field, and (ii) a twisted tube which environment is plasma with also twisted magnetic field. The magnetic field twist in given region is characterized by the ratio of azim...

  16. Kelvin-Helmholtz instabilities in Smoothed Particle Hydrodynamics

    CERN Document Server

    Valcke, Sander; Roediger, Elke; Dejonghe, Herwig

    2010-01-01

    In this paper we investigate whether Smoothed Particle Hydrodynamics (SPH), equipped with artificial conductivity, is able to capture the physics of density/energy discontinuities in the case of the so-called shearing layers test, a test for examining Kelvin-Helmholtz (KH) instabilities. We can trace back each failure of SPH to show KH rolls to two causes: i) shock waves travelling in the simulation box and ii) particle clumping, or more generally, particle noise. The probable cause of shock waves is the Local Mixing Instability (LMI), previously identified in the literature. Particle noise on the other hand is a problem because it introduces a large error in the SPH momentum equation. We also investigate the role of artificial conductivity (AC). Including AC is necessary for the long-term behavior of the simulation (e.g. to get $\\lambda=1/2, 1$ KH rolls). In sensitive hydrodynamical simulations great care is however needed in selecting the AC signal velocity, with the default formulation leading to too much ...

  17. MESSENGER observations of multiscale Kelvin-Helmholtz vortices at Mercury

    Science.gov (United States)

    Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Sundberg, Torbjörn; Boardsen, Scott A.; Anderson, Brian J.; Korth, Haje; Solomon, Sean C.

    2015-06-01

    Observations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft in Mercury's magnetotail demonstrate for the first time that Na+ ions exert a dynamic influence on Mercury's magnetospheric system. Na+ ions are shown to contribute up to ~30% of the ion thermal pressure required to achieve pressure balance in the premidnight plasma sheet. High concentrations of planetary ions should lead to Na+ dominance of the plasma mass density in these regions. On orbits with northward-oriented interplanetary magnetic field and high (i.e., >1 cm-3) Na+ concentrations, MESSENGER has often recorded magnetic field fluctuations near the Na+ gyrofrequency associated with the Kelvin-Helmholtz (K-H) instability. These nightside K-H vortices are characteristically different from those observed on Mercury's dayside that have a nearly constant wave frequency of ~0.025 Hz. Collectively, these observations suggest that large spatial gradients in the hot planetary ion population at Mercury may result in a transition from a fluid description to a kinetic description of vortex formation across the dusk terminator, providing the first set of truly multiscale observations of the K-H instability at any of the diverse magnetospheric environments explored in the solar system.

  18. Helicity, topology, and Kelvin waves in reconnecting quantum knots

    Science.gov (United States)

    Clark di Leoni, P.; Mininni, P. D.; Brachet, M. E.

    2016-10-01

    Helicity is a topological invariant that measures the linkage and knottedness of lines, tubes, and ribbons. As such, it has found myriads of applications in astrophysics, fluid dynamics, atmospheric sciences, and biology. In quantum flows, where topology-changing reconnection events are a staple, helicity appears as a key quantity to study. However, the usual definition of helicity is not well posed in quantum vortices, and its computation based on counting links and crossings of centerline vorticity can be downright impossible to apply in complex and turbulent scenarios. We present a definition of helicity which overcomes these problems and which gives the expected result in the large-scale limit. With it, we show that certain reconnection events can excite Kelvin waves and other complex motions of the centerline vorticity, which slowly deplete helicity as they interact nonlinearly, thus linking the theory of vortex knots with observations of quantum fluids. This process also results in the depletion of helicity in a fully turbulent quantum flow, in a way reminiscent of the decay of helicity in classical fluids.

  19. Highly Efficient and Stable Novel NanoBiohybrid Catalyst to Avert 3,4-Dihydroxybenzoic Acid Pollutant in Water

    Science.gov (United States)

    Das, Rasel; Hamid, Sharifah Bee Abd; Annuar, Mohamad Suffian Mohamad

    2016-01-01

    The present study reported for the first time covalent immobilization of protocatechuate 3,4-dioxygenase (3,4-POD) onto functionalized multi-walled carbon nanotubes (F-MWCNT) for degrading the toxic 3,4-dihydroxybenzoic acid (3,4-DHBA) pollutant in water. The F-MWCNTs had a maximum 3,4-POD loading of 1060 μg/mg. Immobilized 3,4 POD had 44% of relative structural changes to its free configurations. Nevertheless, >90% of relative activity and about 50% of catalytic efficiency were retained to the free enzyme. Immobilized 3,4-POD demonstrated higher alkaline stability and thermostability than the free 3,4-POD. The free and immobilized 3,4-POD lost 82% and 66% of relative activities, respectively after 180 min of incubations at 90 °C. Excellent shelf-life was observed for the immobilized 3,4-POD with residual activity of 56% compared with 41% and 39% of the free 3,4-POD at 4 °C and 25 °C over 30 days storage. Immobilized 3,4-POD showed >60% of catalytic activity retention even after ten-cycle uses, defraying the expenses of free 3,4-POD productions for long term uses. Finally, the immobilized 3,4-POD removed 71% of 3,4-DHBA from water in <4 h, paving its future application for water purification with reduced costs and time. PMID:27721429

  20. Stabilization of nonhomogeneous beam by embedding patch of Kelvin-Voigt viscoelasticity%嵌有Kelvin-Voigt阻尼片的非均质梁的镇定

    Institute of Scientific and Technical Information of China (English)

    陈叔平; 司守奎

    2003-01-01

    With the help of operator semigroup theory, the frequency domain method and the multiplier techniques wereapplied. When the Kelvin-Voigt damping was distributed locally on any subinterval of the region, the energy of the nonhomoge-neous Euler-Bernoulli beam was proved to decay uniformly exponentially.%借助于算子半群理论.应用频域方法和乘子技巧,证明了具有局部Kelvin-Voigt阻尼的非均质Euler-Bernoulli梁的能量是指数衰减的.

  1. Interaction and decay of Kelvin waves in the Gross-Pitaevskii model

    OpenAIRE

    Proment, Davide; Barenghi, Carlo F.; Onorato, Miguel

    2013-01-01

    By solving numerically the governing Gross-Pitaevskii equation, we study the dynamics of Kelvin waves on a superfluid vortex. After determining the dispersion relation, we monitor the turbulent decay of Kelvin waves with energy initially concentrated at large length scales. At intermediate length scales, we find that the decay is consistent with scaling predictions of theoretical models. Finally we report the unexpected presence of large-length scale phonons in the system.

  2. A 10 Kelvin 3 Tesla Magnet for Space Flight ADR Systems

    Science.gov (United States)

    Tuttle, Jim; Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Riall, Sara; Pourrahimi, Shahin

    2003-01-01

    Many future space flight missions are expected to use adiabatic demagnetization refrigerators (ADRs) to reach detector operating temperatures well below one Kelvin. The goal is to operate each ADR with a mechanical cooler as its heat sink, thus avoiding the use of liquid cryogens. Although mechanical coolers are being developed to operate at temperatures of 6 Kelvin and below, there is a large efficiency cost associated with operating them at the bottom of their temperature range. For the multi-stage ADR system being developed at Goddard Space Flight Center, the goal is to operate with a 10 Kelvin mechanical cooler heat sink. With currently available paramagnetic materials, the highest temperature ADR stage in such a system will require a magnetic field of approximately three Tesla. Thus the goal is to develop a small, lightweight three Tesla superconducting magnet for operation at 10 Kelvin. It is important that this magnet have a low current/field ratio. Because traditional NbTi magnets do not operate safely above about six Kelvin, a magnet with a higher Tc is required. The primary focus has been on Nb3Sn magnets. Since standard Nb3Sn wire must be coated with thick insulation, wound on a magnet mandrel and then reacted, standard Nb,Sn magnets are quite heavy and require high currents Superconducting Systems developed a Nb3Sn wire which can be drawn down to small diameter, reacted, coated with thin insulation and then wound on a small diameter coil form. By using this smaller wire and operating closer to the wire s critical current, it should be possible to reduce the mass and operating current of 10 Kelvin magnets. Using this "react-then-wind" technology, Superconducting Systems has produced prototype 10 Kelvin magnets. This paper describes the development and testing of these magnets and discusses the outlook for including 10 Kelvin magnets on space-flight missions.

  3. (E-3-(4-Bromophenyl-1-(3,4-dichlorophenylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Rajni Kant

    2009-04-01

    Full Text Available The molecule of the title compound, C15H9BrCl2O, is shown to be the E isomer, with the 3,4-dichlorobenzoyl and p-bromophenyl substituents in trans positions with respect to the chalcone olefin bond. The molecule is non-planar, the two aromatic rings forming a dihedral angle of 49.58 (1°.

  4. Kelvin Notation for Stabilizing Elastic-Constant Inversion Notation Kelvin pour stabiliser l'inversion de constantes élastiques

    Directory of Open Access Journals (Sweden)

    Dellinger J.

    2006-12-01

    Full Text Available Inverting a set of core-sample traveltime measurements for a complete set of 21 elastic constants is a difficult problem. If the 21 elastic constants are directly used as the inversion parameters, a few bad measurements or an unfortunate starting guess may result in the inversion converging to a physically impossible solution . Even given perfect data, multiple solutions may exist that predict the observed traveltimes equally well. We desire the inversion algorithm to converge not just to a physically possible solution, but to the best(i. e. most physically likely solution of all those allowed. We present a new parameterization that attempts to solve these difficulties. The search space is limited to physically realizable media by making use of the Kelvin eigenstiffness-eigentensor representation of the 6 x 6 elastic stiffness matrix. Instead of 21 stiffnesses, there are 6 eigenstiffness parametersand 15 rotational parameters . The rotational parameters are defined using a Lie-algebra representation that avoids the artificial degeneracies and coordinate-system bias that can occur with standard polar representations. For any choice of these 21 real parameters, the corresponding stiffness matrix is guaranteed to be physically realizable. Furthermore, all physically realizable matrices can be represented in this way. This new parameterization still leaves considerable latitude as to which linear combinations of the Kelvin parameters to use, and how they should be ordered. We demonstrate that by careful choice and ordering of the parameters, the inversion can be relaxedfrom higher to lower symmetry simply by adding a few more parameters at a time. By starting from isotropy and relaxing to the general result in stages (isotropy, transverse isotropy, orthorhombic, general, we expect that the method should find the solution that is closest to isotropy of all those that fit the data. L'inversion d'un ensemble de mesures du temps de parcours d

  5. Effects of 3,4-Dichloroaniline on Testicle Enzymes as Biological Markers in Rats

    Institute of Scientific and Technical Information of China (English)

    Bo ZHANG; SEN LIN

    2009-01-01

    Objective To investigate the effects of 3,4-dichlomaniline (3,4-DCA) on activities of testicle enzymes as biological markers in rats. Methods Fifty male rats were randomly divided into 5 groups (n=10). One group was left untreated and used as a solvent control (administered orally by corn oil), while the other 4 groups were treated with 3, 4-DCA. Corn oil was used as a solvent, and 3,4-DCA was diluted into tested concentrations (39, 81, 170, and 357 mg/kg). All the groups orally administered 3,4-DCA or corn oil, once a day for 4 weeks. The testicle tissue was homogenized in a 0.1 mol/L potassium phosphate buffer (0.1 mol/L, pH 7.2). The crude homogenate was centrifuged at 6000 rpm for 5 rain at 4 ℃. The supematant obtained was used as an enzyme extract for determination of the enzyme activities. Results Compared with the control, the activities of ALP, ACE and SDH were increased significantly at a lower level of 3,4-DCA, and decreased at a higher level of 3, 4-DCA, whreas the activities of LDH, LDH-X, and G6PDH were inhibited significantly with the increased 3,4-DCA concentration. Organ coefficient "organ weight/total body weight × 100" of testis, liver, and spleen increased significantly with the increased 3,4-DCA concentration. These results suggest that 3,4-DCA toxicity to the male reproductive system was associated with the activities of testicular enzymes which are the sensitive biochemical endpoints reflecting 3,4-DCA toxicity to the male reproductive system. Conclusion 3,4-DCA has toxicity to the reproductive system in male rats.

  6. Kelvin probe force microscopy in liquid using electrochemical force microscopy

    Directory of Open Access Journals (Sweden)

    Liam Collins

    2015-01-01

    Full Text Available Conventional closed loop-Kelvin probe force microscopy (KPFM has emerged as a powerful technique for probing electric and transport phenomena at the solid–gas interface. The extension of KPFM capabilities to probe electrostatic and electrochemical phenomena at the solid–liquid interface is of interest for a broad range of applications from energy storage to biological systems. However, the operation of KPFM implicitly relies on the presence of a linear lossless dielectric in the probe–sample gap, a condition which is violated for ionically-active liquids (e.g., when diffuse charge dynamics are present. Here, electrostatic and electrochemical measurements are demonstrated in ionically-active (polar isopropanol, milli-Q water and aqueous NaCl and ionically-inactive (non-polar decane liquids by electrochemical force microscopy (EcFM, a multidimensional (i.e., bias- and time-resolved spectroscopy method. In the absence of mobile charges (ambient and non-polar liquids, KPFM and EcFM are both feasible, yielding comparable contact potential difference (CPD values. In ionically-active liquids, KPFM is not possible and EcFM can be used to measure the dynamic CPD and a rich spectrum of information pertaining to charge screening, ion diffusion, and electrochemical processes (e.g., Faradaic reactions. EcFM measurements conducted in isopropanol and milli-Q water over Au and highly ordered pyrolytic graphite electrodes demonstrate both sample- and solvent-dependent features. Finally, the feasibility of using EcFM as a local force-based mapping technique of material-dependent electrostatic and electrochemical response is investigated. The resultant high dimensional dataset is visualized using a purely statistical approach that does not require a priori physical models, allowing for qualitative mapping of electrostatic and electrochemical material properties at the solid–liquid interface.

  7. 基于分数阶微积分的Kelvin-Voigt流变模型%The Kelvin-Voigt Rheological Model Based on Fractional Calculus

    Institute of Scientific and Technical Information of China (English)

    郭佳奇; 乔春生; 徐冲; 黄山秀

    2009-01-01

    为研究岩土材料的应力、应变和时间的关系,基于分数阶微积分理论,定义含分数阶导数的力学元件(FC元件),推导FC元件的蠕变柔量和松弛模量.与牛顿体元件相比,FC元件能更好地反映流变问题的非线性渐变过程.借鉴经典元件组合模型的建模思路,用FC元件取代整数阶微积分Kelvin-Voigt流变模型中的牛顿体元件,形成基于分数阶微积分的Kelvin-Voigt流变模型.应用离散化求Laplace逆变换的方法以及H-Fox函数,得出分数阶微积分Kelvin-Voigt流变模型的本构方程、蠕变方程、松弛方程、蠕变柔量及松弛模量的解析表达式.采用整数阶微积分Kelvin-Voigt流变模型、整数阶5参数开尔文流变模型和分数阶微积分Kelvin-Voigt流变模型对试验数据拟合的结果表明,分数阶微积分Kelvin-Voigt流变模型不但拟合精度高,能够克服整数阶微积分Kelvin-Voigt流变模型在蠕变初期及蠕变曲线拐点附近与试验数据不能很好吻合的弊端,而且能够在保证拟合精度的条件下,减少本构模型中的参数.

  8. 机织建筑膜材料的广义Kelvin-Voigt蠕变模型%General Kelvin-Voigt creep model of fabric architectural membrane

    Institute of Scientific and Technical Information of China (English)

    张伍连; 丁辛; 杨旭东

    2011-01-01

    The uniaxial tension creep tests of PVC coating membrane with plain architectural are experimented along the warp and weft direction at five different stresses. The general Kelvin -Voigt creep formulas are given. The experimental data are studied through the use of these creep formulas with three, five and seven parameters. The result shows: As the number of the parameters grew, prediction complexity is increased with grade. When the parameter is seven, the coefficients of determination are over 99.9% at different stresses. This shows that the general Kelvin-Voigt creep model with seven parameters can well predict creeping behavior of fabric architectural membrane.%对平纹组织为基布的PVC涂层膜材料进行了经纬两方向各自5种不同应力条件下的单轴向拉伸蠕变试验,给出了广义Kelvin-Voigt模型的具体蠕变方程,并利用广义三参数、五参数与七参数Kelvin-Voigt的蠕变方程对实验数据进行了分析.结果显示:随着模型参数个数的增加,预测效果也呈现出递增趋势;当模型参数为7个时,各应力拟合的确定系数均在99.9%以上,表明七参数广义Kelvin-Voigt蠕变模型已可以很好地预测膜材料的蠕变特性.

  9. Dinosaur Day!

    Science.gov (United States)

    Nakamura, Sandra; Baptiste, H. Prentice

    2006-01-01

    In this article, the authors describe how they capitalized on their first-grade students' love of dinosaurs by hosting a fun-filled Dinosaur Day in their classroom. On Dinosaur Day, students rotated through four dinosaur-related learning stations that integrated science content with art, language arts, math, and history in a fun and time-efficient…

  10. CEMI Days

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-07-01

    CEMI Days are an important channel of engagement between DOE and the manufacturing industry to identify challenges and opportunities for increasing U.S. manufacturing competitiveness. CEMI Days that are held at manufacturing companies’ facilities can include tours of R&D operations or other points of interest determined by the host company.

  11. 40 CFR 257.3-4 - Ground water.

    Science.gov (United States)

    2010-07-01

    ... to sewage sludge that is not used or disposed through a practice regulated in 40 CFR part 503 may... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Ground water. 257.3-4 Section 257.3-4... and Practices § 257.3-4 Ground water. (a) A facility or practice shall not contaminate an...

  12. Gyroresonance of Kelvin-Helmholtz vortices with Na+ in Mercury's magnetotail

    Science.gov (United States)

    Gingell, Peter; Sundberg, Torbjorn; Burgess, David

    2015-04-01

    Observations of Mercury's plasma environment by the MESSENGER spacecraft have revealed that the planet hosts a strongly asymmetric magnetosphere as a result of an off-axis internal magnetic field, and significant finite Larmor radius effects at the boundary layer between magnetospheric and solar wind plasma environments. Linear analysis and global hybrid simulations suggest asymmetric growth of the Kelvin-Helmholtz instability between the dusk and dawn flanks of the magnetopause, and indeed Kelvin-Helmholtz waves have been observed almost exclusively at the dusk flank during northward IMF. A previous study has shown that Kelvin-Helmholtz waves at the dusk flank are observed predominantly at scales associated with the gyration of hot sodium ions - a population originating at the dayside exosphere, and distributed preferentially at the dusk flank. This suggests that a resonance may occur between sodium ion gyration and Kelvin-Helmholtz vortex growth. Using two- and three-dimensional local hybrid simulations of dusk and dawn boundaries, with varying magnetospheric sodium ion density, we have reproduced the main observational features: we see a strong peak in the Kelvin-Helmholtz wave spectra at sodium gyro scales at the dusk boundaries, and suppression of the growth of vortices at the dawn boundaries. We examine the mechanism of the resonant interaction between counter-gyrating sodium ions and K-H vortices using test particle simulations. Finally, we discuss the effect of the sodium ion population on cross-boundary particle transport.

  13. Experiments R285-3/4/5 (ILAS 3/4/5). Activity calculations

    International Nuclear Information System (INIS)

    In the irradiation experiments ILAS 3/4/5 a number of different austenitic stainless steel types and three types of vanadium samples for advanced nuclear systems will be irradiated at a temperature of 300 C up to dpa (displacements per atom) levels of 2.5 dpa for the steel samples and up to 6 dpa for the vanadium samples. In this report the results of the activity calculations of the sample holder material and of the different types of sample materials are presented. The activity of the holder material is calculated for the vertical average of the irradiation position. The activities of the sample materials are given for the vertical maximum of the irradiation position. A relation is given to convert these data to any vertical sample position. Also the changes in chemical composition of the different sample materials, due to nuclide transmutation, are given in this report. (orig.)

  14. Determination of Contact Potential Difference by the Kelvin Probe (Part I I. Basic Principles of Measurements

    Directory of Open Access Journals (Sweden)

    Vilitis O.

    2016-04-01

    Full Text Available Determination of electric potential difference using the Kelvin probe, i.e. vibrating capacitor technique, is one of the most sensitive measuring procedures in surface physics. Periodic modulation of distance between electrodes leads to changes in capacitance, thereby causing current to flow through the external circuit. The procedure of contactless, non-destructive determination of contact potential difference between an electrically conductive vibrating reference electrode and an electrically conductive sample is based on precise control measurement of Kelvin current flowing through a capacitor. The present research is devoted to creation of a new low-cost miniaturised measurement system to determine potential difference in real time and at high measurement resolution. Furthermore, using the electrode of a reference probe, the Kelvin method leads to both the indirect measurement of an electronic work function, or a contact potential of sample, and of a surface potential for insulator type samples.

  15. Non-linear dynamics of Kelvin-Helmholtz unstable magnetized jets three-dimensional effects

    CERN Document Server

    Keppens, R

    1999-01-01

    A numerical study of the Kelvin-Helmholtz instability in compressible magnetohydrodynamics is presented. The three-dimensional simulations consider shear flow in a cylindrical jet configuration, embedded in a uniform magnetic field directed along the jet axis. The growth of linear perturbations at specified poloidal and axial mode numbers demonstrate intricate non-linear coupling effects. The physical mechanims leading to induced secondary Kelvin-Helmholtz instabilities at higher mode numbers are identified. The initially weak magnetic field becomes locally dominant in the non-linear dynamics before and during saturation. Thereby, it controls the jet deformation and eventual breakup. The results are obtained using the Versatile Advection Code [G. Toth, Astrophys. Lett. Comm. 34, 245 (1996)], a software package designed to solve general systems of conservation laws. An independent calculation of the same Kelvin-Helmholtz unstable jet configuration using a three-dimensional pseudo-spectral code gives important ...

  16. MAY DAY

    Institute of Scientific and Technical Information of China (English)

    李佳

    2009-01-01

    @@ May 1 is Intemational Labour Day.It is a great holiday for the working class.On this day working people all over the world demonstrate(显示)their power and solidarity(团结).It has its origins(起因,起源)in the struggle for shorter working hours.In 1884,eight Labour Unions of the United States and Canada held a convention(集会)in Chicago(芝加哥).Here it was decided to wage(开展)a united struggle to win the eight-hour day.A resolution(决议) was adopted (通过)fixing May1,1886,for a great nationwide(全国性的)demonstration(示威).

  17. Impact of atmospheric convectively coupled equatorial Kelvin waves on upper ocean variability

    Science.gov (United States)

    Baranowski, Dariusz B.; Flatau, Maria K.; Flatau, Piotr J.; Matthews, Adrian J.

    2016-03-01

    Convectively coupled Kelvin waves (CCKWs) are atmospheric weather systems that propagate eastward along the equatorial wave guide with phase speeds between 11 and 14 m s-1. They are an important constituent of the convective envelope of the Madden-Julian oscillation (MJO), for which ocean-atmosphere interactions play a vital role. Hence, ocean-atmosphere interactions within CCKWs may be important for MJO development and prediction and for tropical climate, in general. Although the atmospheric structure of CCKWs has been well studied, their impact on the underlying ocean is unknown. In this paper, the ocean-atmosphere interactions in CCKWs are investigated by a case study from November 2011 during the CINDY/DYNAMO field experiment, using in situ oceanographic measurements from an ocean glider. The analysis is then extended to a 15 year period using precipitation data from the Tropical Rainfall Measuring Mission and surface fluxes from the TropFlux analysis. A methodology is developed to calculate trajectories of CCKWs. CCKW events are strongly controlled by the MJO, with twice as many CCKWs observed during the convectively active phase of the MJO compared to the suppressed phase. Coherent ocean-atmosphere interaction is observed during the passage of a CCKW, which lasts approximately 4 days at any given longitude. Surface wind speed and latent heat flux are enhanced, leading to a transient suppression of the diurnal cycle of sea surface temperature (SST) and a sustained decrease in bulk SST of 0.1°C. Given that a typical composite mean MJO SST anomaly is of the order of 0.3°C, and more than one CCKW can occur during the active phase of a single MJO event, the oceanographic impact of CCKWs is of major importance to the MJO cycle.

  18. A validated non-linear Kelvin-Helmholtz benchmark for numerical hydrodynamics

    Science.gov (United States)

    Lecoanet, D.; McCourt, M.; Quataert, E.; Burns, K. J.; Vasil, G. M.; Oishi, J. S.; Brown, B. P.; Stone, J. M.; O'Leary, R. M.

    2016-02-01

    The non-linear evolution of the Kelvin-Helmholtz instability is a popular test for code verification. To date, most Kelvin-Helmholtz problems discussed in the literature are ill-posed: they do not converge to any single solution with increasing resolution. This precludes comparisons among different codes and severely limits the utility of the Kelvin-Helmholtz instability as a test problem. The lack of a reference solution has led various authors to assert the accuracy of their simulations based on ad hoc proxies, e.g. the existence of small-scale structures. This paper proposes well-posed two-dimensional Kelvin-Helmholtz problems with smooth initial conditions and explicit diffusion. We show that in many cases numerical errors/noise can seed spurious small-scale structure in Kelvin-Helmholtz problems. We demonstrate convergence to a reference solution using both ATHENA, a Godunov code, and DEDALUS, a pseudo-spectral code. Problems with constant initial density throughout the domain are relatively straightforward for both codes. However, problems with an initial density jump (which are the norm in astrophysical systems) exhibit rich behaviour and are more computationally challenging. In the latter case, ATHENA simulations are prone to an instability of the inner rolled-up vortex; this instability is seeded by grid-scale errors introduced by the algorithm, and disappears as resolution increases. Both ATHENA and DEDALUS exhibit late-time chaos. Inviscid simulations are riddled with extremely vigorous secondary instabilities which induce more mixing than simulations with explicit diffusion. Our results highlight the importance of running well-posed test problems with demonstrated convergence to a reference solution. To facilitate future comparisons, we include as supplementary material the resolved, converged solutions to the Kelvin-Helmholtz problems in this paper in machine-readable form.

  19. Energy Day.

    Science.gov (United States)

    Thomas, Peter

    1997-01-01

    Describes a program in which students present their displays in the normal science-fair style but without the competitive element and more as a "science-share". Describes an "energy day" celebration which included an energy exhibition and engaged students in an "energy decathlon" that challenged them with tasks encompassing many aspects of energy.…

  20. PROBING STRESS EFFECTS IN SINGLE CRYSTAL ORGANIC TRANSISTORS BY SCANNING KELVIN PROBE MICROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Teague, L

    2010-06-11

    We report scanning Kelvin probe microscopy (SKPM) of single crystal difluoro bis(triethylsilylethynyl) anthradithiophene (diF-TESADT) organic transistors. SKPM provides a direct measurement of the intrinsic charge transport in the crystals independent of contact effects and reveals that degradation of device performance occurs over a time period of minutes as the diF-TESADT crystal becomes charged.

  1. Kelvin-Voigt均匀黏弹性介质中传播的地震波

    Institute of Scientific and Technical Information of China (English)

    苑春方; 彭苏萍; 张中杰; 刘振宽

    2005-01-01

    研究了在小扰动的情况下, 地震波在Kelvin-Voigt均匀黏弹性介质中传播时的瞬态响应以及对应的三阶偏微分方程的解析解. 获得了在脉冲震源条件下Kelvin-Voigt均匀黏弹性三阶波动方程的平面波解. 运用脉冲叠加原理, 获得了在任意震源条件下Kelvin-Voigt均匀黏弹性三阶波动方程的平面波解. 讨论了地震波在Kelvin-Voigt均匀黏弹性介质中的传播速度和衰减, 推导出了地震波的衰减系数和传播速度与介质的密度、弹性模量和黏滞系数之间的精确关系. 这些结果能够用于地震勘探中黏弹性岩性参数的反演.

  2. Seismic wave propagating in Kelvin-Voigt homogeneous visco-elastic media

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper studies, under a small disturbance, the responses of seismic transient wave in the visco-elastic media and the analytic solution of the corresponding third-order partial differential equation. A plane wave solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differential equation with a pulse source is obtained. By the principle of pulse stacking of particle vibration, the result is extended to the solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differential equation with any source. The velocities of seismic wave propagating and the attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are discussed. The velocities of seismic wave propagating and the coefficient of attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are derived, expressed as functions of density of the media, elastic modulus and visco-elastic coefficient. These results can be applied in inversing lithology parameters in geophysical prospecting.

  3. EIGEN THEORY OF VISCOELASTIC DYNAMICS BASED ON THE KELVIN-VOIGT MODEL

    Institute of Scientific and Technical Information of China (English)

    郭少华

    2004-01-01

    Using the eigen theory of solid mechanics, the eigen properties of anisotropic viscoelastic bodies with Kelvin-Voigt model were studied, and the generalized Stokes equation of anisotropic viscoelastic dynamics was obtained, which gives the threedimensional pattern of viscoelastical waves. The laws of viscoelastical waves of different anisotropical bodies were discussed. Several new conclusiones are given.

  4. Exponential stability of an elastic string with local Kelvin-Voigt damping

    Science.gov (United States)

    Zhang, Qiong

    2010-12-01

    This paper is devoted to analyzing an elastic string with local Kelvin-Voigt damping. We prove the exponential stability of the system when the material coefficient function near the interface is smooth enough. Our method is based on the frequency method and semigroup theory.

  5. Reproductive solutions for the g-Navier-Stokes and g-Kelvin-Voight equations

    Directory of Open Access Journals (Sweden)

    Luis Friz

    2016-01-01

    Full Text Available This article presents the existence of reproductive solutions of g-Navier-Stokes and g-Kelvin-Voight equations. In this way, for weak solutions, we reach basically the same result as for classic Navier-Stokes equations.

  6. Comment on ``Are there internal Kelvin waves in Lake Tanganyika?'' by Jaya Naithani and Eric Deleersnijder

    Science.gov (United States)

    Antenucci, Jason P.

    2005-11-01

    Recent numerical modelling efforts have demonstrated the presence of Kelvin waves in Lake Tanganyika (Naithani and Deleersnijder, 2004), however it is claimed that these waves should not appear according to classical scaling arguments. Based on existing classical scaling arguments, supported by laboratory and field investigations, I will show why they can, and apparently do, appear in Lake Tanganyika.

  7. 169 kelvin cryogenic microcooler empoying a condenser, evaporator, flow restriction and counterflow heat exchangers

    NARCIS (Netherlands)

    Burger, Johannes; Holland, Harry; Berenschot, Erwin; Seppenwolde, Jan-Henry; Brake, ter Marcel; Gardeniers, Han; Elwenspoek, Miko

    2001-01-01

    This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube c

  8. The Kelvin Wave Processes in the Equatorial Indian Ocean during the 2006-2008 IOD Events

    Institute of Scientific and Technical Information of China (English)

    DU Yan; LIU Kai; ZHUANG Wei; YU Wei-Dong

    2012-01-01

    The present study investigates the role of Kelvin wave propagations along the equatorial Indian Ocean during the 2006-2008 Indian Ocean Dipole (IOD). The 2006 IOD lasted for seven months, developing in May and reaching its peak in December, while the 2007 and 2008 IODs were short-lived events, beginning in ear- ly May and ending abruptly in September, with much weaker amplitudes. Associated with the above IODs, the impulses of the sea surface height (SSH) anomalies reflect the forcing from an intraseasonal time scale, which was important to the evolution of IODs in 2007 and 2008. At the thermocline depth, dominated by the propagation of Kelvin waves, the warming/cooling temperature signals could reach the surface at a particular time. When the force is strong and the local thermocline condition is fa- vorable, the incoming Kelvin waves dramatically impact the sea surface temperature (SST) in the eastern equatorial Indian Ocean. In July 2007 and late July 2008, the downwelling Kelvin waves, triggered by the Mad- den-Julian Oscillation (MJO) in the eastern and central equatorial Indian Ocean, suppressed the thermocline in the Sumatra and the Java coast and terminated the IOD, which made those events short-lived and no longer persist into the boreal fall season as the canonical IOD does.

  9. Kelvin-Helmholtz instability at the magnetotail boundary: MHD simulation and comparison with Geotail observations

    Science.gov (United States)

    Otto, A.; Fairfield, D. H.

    2000-09-01

    On March 24, 1995, the Geotail spacecraft observed large fluctuations of the magnetic field and plasma properties in the low-latitude boundary layer about 15 RE tailward of the dusk meridian. Although the magnetospheric and magnetosheath magnetic fields were strongly northward, the Bz component showed strong short-duration fluctuations in which Bz could even reach negative values. We have used two-dimensional magnetohydrodynamic simulations with magnetospheric and magnetosheath input parameters specifically chosen for this Geotail event to identify the processes which cause the observed boundary properties. It is shown that these fluctuations can be explained by the Kelvin-Helmholtz instability if the k vector of the instability has a component along the magnetic field direction. The simulation results show many of the characteristic properties of the Geotail observations. In particular, the quasi-periodic strong fluctuations are well explained by satellite crossings through the Kelvin-Helmholtz vortices. It is illustrated how the interior structure of the Kelvin-Helmholtz vortices leads to the rapid fluctuations in the Geotail observations. Our results suggest an average Kelvin-Helmholtz wavelength of about 5 RE, with a vortex size of close to 2 RE for an average repetition time of 2.5 min. The growth time for these waves implies a source region of about 10-16 RE upstream from the location of the Geotail spacecraft (i.e., near the dusk meridian). The results also indicate a considerable mass transport of magnetosheath material into the magnetosphere by magnetic reconnection in the Kelvin-Helmholtz vortices.

  10. 具有Kelvin-Voigt阻尼的弱耦合系统的能量衰减估计%Energy decay estimates for the weakly coupled systems with Kelvin-Voigt damping

    Institute of Scientific and Technical Information of China (English)

    樊美丽; 章春国; 谷尚武

    2014-01-01

    This paper studies the weakly coupled systems with Kelvin-Voigt damping. First, under the appro-priate hypothesis, we prove the well-posedness of the system by using the theory of linear operator semigroup. And then, we show that the energy of the weakly coupled system with Kelvin-Voigt damping is uniform expo-nential decay by applying the frequency domain result on Hilbert space.%研究具有 Kelvin-Voigt 阻尼的弱耦合系统。首先在合适的假设条件下,应用线性算子半群理论证明了系统的适定性;进而运用线性算子半群的频域定理证明了具有Kelvin-Voigt阻尼的弱耦合梁―弦系统的能量是一致指数衰减的。

  11. Acid-base site detection and mapping on solid surfaces by Kelvin force microscopy (KFM).

    Science.gov (United States)

    Gouveia, Rubia F; Bernardes, Juliana S; Ducati, Telma R D; Galembeck, Fernando

    2012-12-01

    Electrostatic potential at the surface of acidic or basic solids changes under higher relative humidity (RH), as determined by using Kelvin force microscopy (KFM). The potential on acid surfaces becomes more negative as the water vapor pressure increases, while it becomes more positive on basic solids. These results verify the following hypothesis: OH(-) or H(+) ions associated with atmospheric water ion clusters are selectively adsorbed on solid surfaces, depending on the respective Brønsted acid or base character. Therefore, Kelvin microscopy, under variable humidity, is a rigorous but convenient alternative to determine the acid-base character of solid surfaces, with a great advantage: it uses only one amphoteric and simple reagent to determine both the acid and base sites. Moreover, this technique provides information on the spatial distribution of acid-base sites, which is currently inaccessible to any other method.

  12. Three Dimensional Motions, Kelvin Waves, and Nanoparticle Tracking in Superfluid Helium

    Science.gov (United States)

    Meichle, David; Lathrop, Daniel

    2013-11-01

    Liquid Helium becomes a quantum superfluid when cooled below the lambda transition temperature of 2.17 Kelvin. Superfluid helium exhibits interesting macroscopic effects such as zero viscosity; and its flow is irrotational except for the presence of line-like topological phase defects with quantized circulation called quantum vortices. The vortex dynamics can be observed by dispersing tracer particles into the fluid, which become trapped on the vortex cores. Using atmospheric ice particles our group recently observed the excitation and self-similar propagation of helical Kelvin waves on these quantized vortex cores following a vortex reconnection event. This observation of an intrinsically three dimensional phenomenon has motivated the development of a three dimensional imaging apparatus for liquid helium. We will present new data obtained by dispersing fluorescent nanoparticles tracers and our progress towards full three dimensional tracking of quantized vortex dynamics in liquid helium.

  13. THE DYNAMIC BEHAVIORS OF VISCOELASTIC PIPE CONVEYING FLUID WITH THE KELVIN MODEL

    Institute of Scientific and Technical Information of China (English)

    Wang Zhongmin; Zhao Fengqun; Feng Zhenyu; Liu Hongzhao

    2000-01-01

    Based on the differential constitutive relationship of linear viscoelastic material, a solid-liquid coupling vibration equation for viscoelastic pipe conveying fluid is derived by the D'Alembert's principle. The critical flow velocities and natural frequencies of the cantilever pipe conveying fluid with the Kelvin model ( flutter instability) are calculated with the modified finite difference method in the form of the recurrence for mula. The curves between the complex frequencies of the first, second and third mode and flow velocity of the pipe are plotted. On the basis of the numerical calculation results, the dynamic behaviors and stability of the pipe are discussed. It should be pointed out that the delay time of viscoelastic material with the Kelvin model has a remarkable effect on the dynamic characteristics and stability behaviors of the cantilevered pipe conveying fluid, which is a gyroscopic non-conservative system.

  14. Numerical simulations of Kelvin-Helmholtz instability: a two-dimensional parametric study

    CERN Document Server

    Tian, Chunlin

    2016-01-01

    Using two-dimensional simulations, we numerically explore the dependences of Kelvin-Helmholtz instability upon various physical parameters, including viscosity, width of sheared layer, flow speed, and magnetic field strength. In most cases, a multi-vortex phase exists between the initial growth phase and final single-vortex phase. The parametric study shows that the evolutionary properties, such as phase duration and vortex dynamics, are generally sensitive to these parameters except in certain regimes. An interesting result is that for supersonic flows, the phase durations and saturation of velocity growth approach constant values asymptotically as the sonic Mach number increases. We confirm that the linear coupling between magnetic field and Kelvin-Helmholtz modes is negligible if the magnetic field is weak enough. The morphological behaviour suggests that the multi-vortex coalescence might be driven by the underlying wave-wave interaction. Based on these results, we make a preliminary discussion about seve...

  15. On Advantages of the Kelvin Mapping in Finite Element Implementations of Deformation Processes

    CERN Document Server

    Nagel, Thomas; Moerman, Kevin M; Kolditz, Olaf

    2016-01-01

    Classical continuum mechanical theories operate on three-dimensional Eu-clidian space using scalar, vector, and tensor-valued quantities usually up to the order of four. For their numerical treatment, it is common practice to transform the relations into a matrix-vector format. This transformation is usually performed using the so-called Voigt mapping. This mapping does not preserve tensor character leaving significant room for error as stress and strain quantities follow from different mappings and thus have to be treated differently in certain mathematical operations. Despite its conceptual and notational difficulties having been pointed out, the Voigt mapping remains the foundation of most current finite element programmes. An alternative is the so-called Kelvin mapping which has recently gained recognition in studies of theoretical mechanics. This article is concerned with benefits of the Kelvin mapping in numerical modelling tools such as finite element software. The decisive difference to the Voigt mapp...

  16. The subchronic effects of 3,4-methylendioxymethamphetamine on oxidative stress in rat brain

    Directory of Open Access Journals (Sweden)

    Simić Ivan

    2014-01-01

    Full Text Available The aim of the present study was to evaluate the subchronic effects of 3,4-methylenedioxymethamphetamine on several oxidative stress markers: index of lipid peroxidation (ILP, superoxide dismutase (SOD activity, superoxide radical (O2.- levels, and reduced glutathione (GSH levels in the frontal cortex, striatum and hippocampus of the rat. The study included 64 male Wistar rats (200-250g. The animals were treated per os with of 5, 10, or 20 mg/kg of 3,4-methylenedioxymethamphetamine (MDMA every day for 15 days. The subchronic administration of MDMA resulted in an increase in ILP, SOD and O2.-, and a decrease in GSH, from which we conclude that oxidative stress was induced in rat brain.

  17. A Weakly Nonlinear Model for Kelvin-Helmholtz Instability in Incompressible Fluids

    Institute of Scientific and Technical Information of China (English)

    WANG Li-Feng; YE Wen-Hua; FAN Zheng-Feng; XUE Chuang; LI Ying-Jun

    2009-01-01

    A weakly nonlinear model is proposed for the Kelvin-Helmholtz instability in two-dimensional incompressible fluids by expanding the perturbation velocity potential to third order. The third-order harmonic generation effects of single-mode perturbation are analyzed, as well as the nonlinear correction to the exponential growth of the fundamental modulation. The weakly nonlinear results are supported by numerical simulations. Density and resonance effects exist in the development of mode coupling.

  18. The Kelvin-Helmholtz instability in weakly ionised plasmas II: multifluid effects in molecular clouds

    OpenAIRE

    Jones, A. C.; Downes, T. P

    2011-01-01

    We present a study of the Kelvin-Helmholtz instability in a weakly ionised, multifluid MHD plasma with parameters matching those of a typical molecular cloud. The instability is capable of transforming well-ordered flows into disordered flows. As a result, it may be able to convert the energy found in, for example, bowshocks from stellar jets into the turbulent energy found in molecular clouds. As these clouds are weakly ionised, the ideal magnetohydrodynamic approximation does not apply at s...

  19. Measuring Method of a Surface Property inside the Pore: Application of Kelvin's equation

    OpenAIRE

    Amano, Ken-ichi

    2015-01-01

    Surface analyses inside the nanopore, micropore, and a very narrow pipe are important topics for development of the chemical engineering. Here, we propose a measuring method which evaluates the surface coverage of the chemically modified pore surface and the corrosion rate of the inner surface of the narrow pipe, etc. The method uses Kelvin's equation that expresses saturated vapor pressure of a liquid in the pore (pipe). The surface coverage and the corrosion rate are calculated by measuring...

  20. Kelvin probe force microscopy for local characterisation of active nanoelectronic devices

    OpenAIRE

    Tino Wagner; Hannes Beyer; Patrick Reissner; Philipp Mensch; Heike Riel; Bernd Gotsmann; Andreas Stemmer

    2015-01-01

    Frequency modulated Kelvin probe force microscopy (FM-KFM) is the method of choice for high resolution measurements of local surface potentials, yet on coarse topographic structures most researchers revert to amplitude modulated lift-mode techniques for better stability. This approach inevitably translates into lower lateral resolution and pronounced capacitive averaging of the locally measured contact potential difference. Furthermore, local changes in the strength of the electrostatic inter...

  1. Global Regular Solutions to a Kelvin-Voigt Type Thermoviscoelastic System

    CERN Document Server

    Pawlow, Irena

    2011-01-01

    A classical 3-D thermoviscoelastic system of Kelvin-Voigt type is considered. The existence and uniqueness of a global regular solution is proved without small data assumption. The existence proof is based on the successive approximation method. The crucial part constitute a priori estimates on an arbitrary finite time interval, which are derived with the help of the theory of anisotropic Sobolev spaces with a mixed norm.

  2. Approximate Kelvin-Voigt Fluid Driven by an External Force Depending on Velocity with Distributed Delay

    Directory of Open Access Journals (Sweden)

    Yantao Guo

    2015-01-01

    Full Text Available We consider the approximate 3D Kelvin-Voigt fluid driven by an external force depending on velocity with distributed delay. We investigate the long time behavior of solutions to Navier-Stokes-Voigt equation with a distributed delay external force depending on the velocity of fluid on a bounded domain. By a prior estimate and a contractive function, we give a sufficient condition for the existence of pullback attractor of NSV equation.

  3. Why Was Kelvin's Estimate of the Earth's Age Wrong?

    Science.gov (United States)

    Lovatt, Ian; Syed, M. Qasim

    2014-01-01

    This is a companion to our previous paper in which we give a published example, based primarily on Perry's work, of a graph of ln "y" versus "t" when "y" is an exponential function of "t". This work led us to the idea that Lord Kelvin's (William Thomson's) estimate of the Earth's age was…

  4. Altimetric observations and model simulations of coastal Kelvin waves in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Nienhaus, M.J.; Subrahmanyam, B.; Murty, V.S.N.

    currents, while HYCOM and SODA current anomalies were measured from absolute currents. 3. Results Previous studies (Le Blanc and Boulanger, 2001; Yang et al, 1998) have calculated the equatorial Kelvin wave speed average for both upwelling... showing the locations of the five wavelet analyses calculated using altimetry, SODA and HYCOM simulations. Figure 2: Annual variation of sea surface height anomaly (cm) at 0°N, 77°E from altimetry observations, SODA and HYCOM simulations. Figure 3...

  5. The dynamics of beltramized flows and its relation with the Kelvin waves

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Rafael [Instituto de Desarrollo Humano, Universidad Nacional de General Sarmiento Pcia. de Buenos Aires, Argentina and Depto. de Fisica FCEyN, Universidad de Buenos Aires, Buenos Aires (Argentina); Santini, E Sergio, E-mail: rgonzale@ungs.edu.ar [Instituto de Ciencias, Universidad Nacional de General Sarmiento Pcia. de Buenos Aires (Argentina) and ICRA-BR, Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro (Brazil)

    2011-05-01

    We define the beltramized flow as the sum of an uniform translation and an uniform rotation with a Beltrami flow. Some of their features are studied by solving the Euler equations, for different geometries, taking into account the boundary conditions, and for different symmetries. We show that the Kelvin waves are beltramized flows. Finally, we show that the variational principle found in a previous work, remains valid for the beltramized flow.

  6. Determination of Contact Potential Difference by the Kelvin Probe (Part I) I. Basic Principles of Measurements

    Science.gov (United States)

    Vilitis, O.; Rutkis, M.; Busenberg, J.; Merkulov, D.

    2016-04-01

    Determination of electric potential difference using the Kelvin probe, i.e. vibrating capacitor technique, is one of the most sensitive measuring procedures in surface physics. Periodic modulation of distance between electrodes leads to changes in capacitance, thereby causing current to flow through the external circuit. The procedure of contactless, non-destructive determination of contact potential difference between an electrically conductive vibrating reference electrode and an electrically conductive sample is based on precise control measurement of Kelvin current flowing through a capacitor. The present research is devoted to creation of a new low-cost miniaturised measurement system to determine potential difference in real time and at high measurement resolution. Furthermore, using the electrode of a reference probe, the Kelvin method leads to both the indirect measurement of an electronic work function, or a contact potential of sample, and of a surface potential for insulator type samples. In the article, the first part of the research, i.e., the basic principles and prerequisites for establishment of such a measurement system are considered.

  7. Impact of MHD shock physics on magnetosheath asymmetry and Kelvin-Helmholtz instability

    Science.gov (United States)

    Nykyri, K.

    2013-08-01

    We have performed 13 three-dimensional global magnetohydrodynamic (MHD) simulations of the magnetosheath plasma and magnetic field properties for Parker spiral (PS) and ortho-Parker spiral interplanetary magnetic field (IMF) orientations corresponding to a wide range of solar wind plasma conditions. To study the growth of the Kelvin-Helmholtz instability on the dawn and dusk flank magnetopause, we have performed 26 local two-dimensional MHD simulations, with the initial conditions taken from global simulations on both sides of the velocity shear layer at the dawn-dusk terminator. These simulations indicate that while the MHD physics of the fast shocks does not directly lead to strong asymmetry of the magnetosheath temperature for typical solar wind conditions, the magnetosheath on the quasi-parallel shock side has a smaller tangential magnetic field along the magnetosheath flow which enables faster growth of the Kelvin-Helmholtz instability (KHI). Because the IMF is statistically mostly in the PS orientation, the KHI formation may statistically favor the dawnside flank. For all the 26 simulations, the growth rates of the KHI correlated well with the ratio of the velocity shear and Alfvén speed along the wave vector, k. Dynamics of the KHI may subsequently lead to formation of kinetic Alfvén waves and reconnection in the Kelvin-Helmholtz vortices which can lead to particle energization. This may partly help to explain the observed plasma sheet asymmetry of cold-component ions, which are heated more on the dawnside plasma sheet.

  8. Properties of the average distribution of equatorial Kelvin waves investigated by ray tracing techniques

    Directory of Open Access Journals (Sweden)

    M. Ern

    2009-06-01

    Full Text Available Kelvin waves excited by tropospheric convection are considered to be one of the main drivers of the stratospheric quasi-biennial oscillation (QBO. In this paper we combine several measured data sets with the Gravity wave Regional Or Global RAy Tracer (GROGRAT in order to study the forcing and vertical propagation of Kelvin waves. Launch distributions for the ray tracer at tropospheric altitudes are deduced from space-time spectra of European Centre for Medium-Range Weather Forecasts (ECMWF operational analyses, as well as outgoing longwave radiation (OLR and rainfall data measured by the Tropical Rainfall Measuring Mission (TRMM satellite. The resulting stratospheric Kelvin wave spectra are compared to ECMWF operational analyses and temperature measurements of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER satellite instrument. Questions addressed are: the relative importance of source variability versus wind modulation, the relative importance of radiative and turbulent damping versus wave breaking, and the minimum altitude where freely propagating waves dominate the spectrum.

  9. Preliminary evidence of motor impairment among polysubstance 3,4-methylenedioxymethamphetamine users with intact neuropsychological functioning

    OpenAIRE

    Bousman, Chad A.; Cherner, Mariana; Emory, Kristen T; BARRON, DANIEL; Grebenstein, Patricia; Atkinson, J. Hampton; Heaton, Robert K.; Grant, Igor

    2010-01-01

    Neuropsychological disturbances have been reported in association with use of the recreational drug “ecstasy,” or 3,4-methylenedioxymethamphetamine (MDMA), but findings have been inconsistent. We performed comprehensive neuropsychological testing examining seven ability domains in 21 MDMA users (MDMA+) and 21 matched control participants (MDMA−). Among MDMA+ participants, median [interquartile range] lifetime MDMA use was 186 [111, 516] doses, with 120 [35–365] days of abstinence. There were ...

  10. 1,3,4-Thiadiazole Based Anticancer Agents.

    Science.gov (United States)

    Aliabadi, Alireza

    2016-01-01

    In recent years, researchers like medicinal chemists in the field of medicinal chemistry have widely utilized the 1,3,4-thiadiazole nucleus to investigate its biological and pharmacological effects. This heterocyclic structure has demonstrated various bioactivities such as antifungal, antimicrobial, antiviral, antileishmanial, anti-inflammatory, antihypertensive, antiepileptic, and anticancer effects among others. Anticancer activity is one of its promising effect as five membered heterocyclic rings have widely been investigated by researchers in the recent years. Herein, we reviewed the chemical structures bearing 1,3,4-thiadiazole template exerting anticancer activity. PMID:27484056

  11. ANTIMICROBIAL ACTIVITIES OF 1,3,4-OXADIAZOLE : A REVIEW

    Directory of Open Access Journals (Sweden)

    Bachwani Mukesh

    2011-06-01

    Full Text Available 1, 3, 4-Oxadiazole is a highly privileged structure the derivatives of which exhibit a wide range of biological activities including antibacterial, antitubercular, vasodialatory, antifungal, cytotoxic, anti-inflammatory and analgesic, hypolipidemic, anticancer and ulcerogenic activities. Resistance to number of antimicrobial agents among a variety of clinically significant species of bacteria is becoming increasingly important global problem. The search for new antimicrobial agents will consequently always remain as an important and challenging task for medicinal chemists. This Review has basic information about 1,3,4-oxadiazole and its antimicrobial activity work for further development in this field.

  12. Reliability of poly 3,4-ethylenedioxythiophene strain gauge

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Lillemose, Michael; Hansen, Thomas Steen;

    2007-01-01

    We report on the experimentally observed reliability of the piezoresistive effect in strained poly 3,4-ethylenedioxythiophene (PEDT). PEDT is an intrinsic conductive polymer which can be patterned by conventional Cleanroom processing, and thus presents a promising material for all-polymer Microsy......We report on the experimentally observed reliability of the piezoresistive effect in strained poly 3,4-ethylenedioxythiophene (PEDT). PEDT is an intrinsic conductive polymer which can be patterned by conventional Cleanroom processing, and thus presents a promising material for all...

  13. Squaroglitter: A 3,4-Connected Carbon Net

    KAUST Repository

    Prasad, Dasari L. V. K.

    2013-08-13

    Theoretical calculations are presented on a new hypothetical 3,4-connected carbon net (called squaroglitter) incorporating 1,4 cyclohexadiene units. The structure has tetragonal space group P4/mmm (No. 123) symmetry. The optimized geometry shows normal distances, except for some elongated bonds in the cyclobutane ring substructures in the network. Squaroglitter has an indirect bandgap of about 1.0 eV. The hypothetical lattice, whose density is close to graphite, is more stable than other 3,4-connected carbon nets. A relationship to a (4,4)nanotube is explored, as is a potential threading of the lattice with metal needles. © 2013 American Chemical Society.

  14. Evaluation of Bcl-2 Family Gene Expression in Hippocampus of 3, 4-methylenedioxymethamphetamine Treated Rats

    OpenAIRE

    Hamed Hashemi-Nasl; Mohammad Taghi Joghataei; Alireza Samzadeh-Kermani; Seyed Behnamedin Jameie; Mansoure Soleimani; Ali Samadikuchaksaraei; Mohammad Hassan Farhadi; Kazem Mousavizadeh; Sara Soleimani Asl; Mehdi Mehdizadeh

    2012-01-01

    Objective: 3,4-methylenedioxymethamphetamine (MDMA) is an illicit, recreational drug that causes cellular death and neurotoxicity. This study evaluates the effects of different doses of MDMA on the expression of apoptosis–related proteins and genes in the hippocampus of adult rats. Materials and Methods: In this expremental study,a total of 20 male Sprague Dawley rats (200-250 g ) were treated with MDMA (0, 5, 10, 20 mg/kg i.p. twice daily) for 7 days. Seven days after the last administration...

  15. Observations of Convectively Coupled Kelvin Waves forced by Extratropical Wave Activity

    Science.gov (United States)

    Kiladis, G. N.; Biello, J. A.; Straub, K. H.

    2012-12-01

    It is well established by observations that deep tropical convection can in certain situations be forced by extratropical Rossby wave activity. Such interactions are a well-known feature of regions of upper level westerly flow, and in particular where westerlies and equatorward wave guiding by the basic state occur at low enough latitudes to interact with tropical and subtropical moisture sources. In these regions convection is commonly initiated ahead of upper level troughs, characteristic of forcing by quasi-geostrophic dynamics. However, recent observational evidence indicates that extratropical wave activity is also associated with equatorial convection even in regions where there is a "critical line" to Rossby wave propagation at upper levels, that is, where the zonal phase speed of the wave is equal to the zonal flow speed. A common manifestation of this type of interaction involves the initiation of convectively coupled Kelvin waves, as well as mixed Rossby-gravity (MRG) waves. These waves are responsible for a large portion of the convective variability within the ITCZ over the Indian, Pacific, and Atlantic sectors, as well as within the Amazon Basin of South America. For example, Kelvin waves originating within the western Pacific ITCZ are often triggered by Rossby wave activity propagating into the Australasian region from the South Indian Ocean extratropics. At other times, Kelvin waves are seen to originate along the eastern slope of the Andes. In the latter case the initial forcing is sometimes linked to a low-level "pressure surge," initiated by wave activity propagating equatorward from the South Pacific storm track. In yet other cases, such as over Africa, the forcing appears to be related to wave activity in the extratropics which is not necessarily propagating into low latitudes, but appears to "project" onto the Kelvin structure, in line with past theoretical and modeling studies. Observational evidence for extratropical forcing of Kelvin and MRG

  16. Synthesis of Novel Biologically Active s-Triazolo[3,4-b]-1,3,4-thiadiazole Derivatives

    Institute of Scientific and Technical Information of China (English)

    SUN,Yi-Feng

    2004-01-01

    @@ Heterocycles bearing a symmetrical triazole or 1,3,4-thiadiazole ring system are reported to show a broad spectrum of biological activities.[1,2] The 1,2,4-triazole nucleus has been recently incorporated into a wide variety of therapeutically interesting drugs including H1/H2 histamine receptor blockers, cholinesterase active agents, CNS stimulants, antianxiety and sedatives[3] Coumarins are nowadays an important group of organic compounds that used as bactericides, fungicides,anti-inflammatory, anticoagulant, anti-HIV and antitumour agents.[4,5] Keeping in view the biological importance of the above mentioned heterocyclic compounds and in continuation of our search for biologically active nitrogen and sulphur heterocycles, a series of s-triazolo[3,4-b]-1,3,4-thiadiazole derivatives was synthesized.

  17. Poly(3,4-ethylenedioxythiophene)-based glucose biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Kros, A.; Nolte, R.J.M. [Nijmegen Univ. (Netherlands). Dept. of Organic Chemistry; Hoevell, S.W.F.M. van [TNO Nutrition and Food Research Inst., Zeist (Netherlands); Sommerdijk, N.A.J.M. [Eindhoven Univ. of Technology (Netherlands). Lab. of Macromolecular and Organic Chemistry

    2001-10-16

    Amperometric biosensors for the recognition of glucose oxidase (GOx) based on poly(3,4-ethylenedioxythiophene) (PEDOT) have for the first time been fabricated and are presented in this communication. This biosensor has potential applications for long-term glucose measurements, e.g., in the treatment of diabetes. (orig.)

  18. (E-Isopropyl 3-(3,4-dihydroxyphenylacrylate

    Directory of Open Access Journals (Sweden)

    Xiao-Hui Zheng

    2011-01-01

    Full Text Available In the title compound, C12H14O4, a derivative of caffeic acid [(E-3-(3,4-dihydroxyphenyl-2-propenoic acid], an intramolecular O—H...O hydrogen bond forms an S(5 ring. In the crystal, intermolecular O—H...O hydrogen bonds link molecules into chains propagating in [110].

  19. 41 CFR 60-3.4 - Information on impact.

    Science.gov (United States)

    2010-07-01

    ... 3-UNIFORM GUIDELINES ON EMPLOYEE SELECTION PROCEDURES (1978) General Principles § 60-3.4 Information... culture regardless of race), whites (Caucasians) other than Hispanic, and totals. The race, sex, and... agencies will consider the general posture of the user with respect to equal employment opportunity for...

  20. Development of Tunneling Spectroscopy Apparatus for Kelvin and Sub-Kelvin Measurements of Superconducting Energy Gaps by Multi-disciplinary students at a Liberal Arts University

    Science.gov (United States)

    Eckhardt, Matt

    2014-03-01

    Tunneling spectroscopy is an important technique used to measure the superconducting energy gap, a feature that is at the heart of the nature of superconductivity in various materials. In this presentation, we report the progress and results in developing high-resolution tunneling spectroscopy experimental platforms in a helium three cryostat, a 3 Kelvin cryocooler and a helium dip-tester. The experimental team working in a liberal arts university is a multi-disciplinary group consisting of one physics major, chemisty majors and a biology major. Students including non-physics majors learned and implemented current-voltage measurement techniques, vacuum system engineering, built electronic boxes and amplifier circuits from scratch, built custom multi-conductor cables for thermometry and current-voltage measurements, and performed conductance measurements. We report preliminary results. Acknowledgments: We acknowledge support from National Science Foundation Grant # DMR-1206561.

  1. Synthesis and Crystal Structure of 3-(4-Ethoxyphenyl)-6-(phenoxymethyl)-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

    Institute of Scientific and Technical Information of China (English)

    LEI Xin-Xiang; LIU Miao-Chang; XIAO Hong-Ping; ZHANG An-Jiang; ZHANG Li-Xue

    2007-01-01

    The title compound C18H16N4O2S has been synthesized by the reaction of 4-amino-3-(4-ethoxyphenyl)-5-mercapto-1,2,4-triazole with phenoxyacetic acid in phospho- rus oxychloride, and characterized by IR, NMR spectra and elemental analysis. Its structure was determined by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 1.4903(3), b = 1.5230(2), c = 0.9615(16) nm, Z = 4, V = 1.7769(5) nm3, Dc = 1.317 g/cm3, ( = 0.201 mm-1, F(000) = 736, R = 0.0795 and wR = 0.2233. In the title compound, all rings are essentially planar.

  2. Total Synthesis of Six 3,4-Unsubstituted Coumarins

    Directory of Open Access Journals (Sweden)

    Wenqing Gao

    2013-12-01

    Full Text Available In this article we describe a new methodology for the total synthesis of 3,4-unsubstituted coumarins from commercially available starting materials. Six examples were prepared, including five naturally occurring coumarins—7-hydroxy-6,8-dimethoxy-coumarin (isofraxidin, 7-hydroxy-6-methoxycoumarin (scopoletin, 6,7,8-trimethoxy-coumarin, 6,7-dimethoxycoumarin (scoparone, and 7,8-dihydroxycoumarin (daphnetin and one synthetic coumarin, 7-hydroxy-6-ethoxycoumarin. Moreover, five important o-hydroxybenzaldehyde intermediates were also obtained, namely 2,4-dihydroxy-3,5-dimethoxybenzaldehyde, 2,4-dihydroxy-5-methoxybenzaldehyde, 5-ethoxy-2,4-dihydroxy-benzaldehyde, 2-hydroxy-3,4,5-trimethoxybenzaldehyde, and 2-hydroxy-4,5-dimethoxy-benzaldehyde. The method developed herein involves just three or four steps and allows for the rapid synthesis of these important molecules in excellent yields. This is the first synthesis of 6,7,8-trimethoxycoumarin and 7-hydroxy-6-ethoxycoumarin.

  3. 20 TO 30-DAY AND 30 TO 60-DAY OSCILLATIONS IN ASSIMILATED GLOBAL DATASETS USING TRMM RAINFALL OBSERVATIONS

    Institute of Scientific and Technical Information of China (English)

    TAO Li; Song YANG; LU Wei-song

    2010-01-01

    The influences of Tropical Rainfall Measuring Mission (TRMM) precipitation products on the structure and underlying physics of intraseasonal oscillation (ISO) are investigated with the U.S. National Aeronautics and Space Administration Goddard Earth Observing System model version 3 (GEOS-3) data assimilation system (DAS). The strong ISO phase in the 1998 summer is apparently located in the Asian monsoon region and the east equatorial Pacific region. The eastward propagation is a dominant feature for the tropical ISO at 20 to 30-day oscillation while the northeastward propagation is the salient ISO at 30 to 60-day oscillation over the 10°N to 25°N belt region. It appears that the Kelvin wave structure is for the tropical 20 to 30-day oscillation. The tropical 30 to 60-day oscillation has the characteristics of the Kelvin-Rossby wave. The impact of satellite-derived precipitation (and its associated latent heating) on the ISO intensity is limited in the GEOS-3 assimilation system. However, its impact on the ISO spatial structures is obvious. Overall, the results demonstrate a better eastward propagation and a northward propagation of ISO with the TRMM precipitation simulation, indicating that latent heating is very important in exciting the equatorial ISO.

  4. Study on the Synthesisof 3,4, 5-Trimethoxytol uene

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The 3,4,5-trimethoxytoluene(TMT) was systhesized using p-cresol by three steps including bromina-tion, methoxylation, and methylation with an overall yield of 84%. The structure of TMT was identified byNMR, GC/MS and IR. “One-pot”method was used in methoxylation and methylation for economical and conve-nient consideration. The mechanism for the methoxylation of 2,6-dibromo-4-methylphenol was discussed.

  5. A modified Kelvin impact model for pounding simulation of base-isolated building with adjacent structures

    Institute of Scientific and Technical Information of China (English)

    Ye Kun; Li Li; Zhu Hongping

    2009-01-01

    Base isolation can effectively reduce the seismic forces on a superstructure, particularly in low- to medium-rise buildings. However, under strong near-fault ground motions, pounding may occur at the isolation level between the base-isolated building (BIB) and its surrounding retaining walls. To effectively investigate the behavior of the BIB pounding with adjacent structures, after assessing some commonly used impact models, a modified Kelvin impact model is proposed in this paper. Relevant parameters in the modified Kelvin model are theoretically derived and numerically verified through a simple pounding case. At the same time, inelasticity of the isolated superstructure is introduced in order to accurately evaluate the potential damage to the superstructure caused by the pounding of the BIB with adjacent structures. The reliability of the modified Kelvin impact model is validated through numerical comparisons with other impact models. However, the difference between the numerical results from the various impact analytical models is not significant. Many numerical simulations of BIBs are conducted to investigate the influence of various design parameters and conditions on the peak inter-story drills and floor accelerations during pounding. It is shown that pounding can substantially increase floor accelerations, especially at the ground floor where impacts occur. Higher modes of vibration are excited during poundings, increasing the inter-story drifts instead of keeping a nearly rigid-body motion of the superstructure. Furthermore, higher ductility demands can be imposed on lower floors of the superstructure. Moreover, impact stiffness seems to play a significant role in the acceleration response at the isolation level and the inter-story drifts of lower floors of the superstructure. Finally, the numerical results show that excessive flexibility of the isolation system used to minimize the floor accelerations may cause the BIB to be more susceptible to pounding

  6. Large Eddy Simulations of Kelvin Helmholtz instabilities at high Reynolds number stratified flows

    Science.gov (United States)

    Brown, Dana; Goodman, Lou; Raessi, Mehdi

    2015-11-01

    Simulations of Kelvin Helmholtz Instabilities (KHI) at high Reynolds numbers are performed using the Large Eddy Simulation technique. Reynolds numbers up to 100,000 are achieved using our model. The resulting data set is used to examine the effect of Reynolds number on various statistics, including dissipation flux coefficient, turbulent kinetic energy budget, and Thorpe length scale. It is shown that KHI are qualitatively different at high Re, up to and including the onset of vortex pairing and billow collapse and quantitatively different afterward. The effect of Richardson number is also examined. The results are discussed as they apply to ocean experiments.

  7. Work function of few layer graphene covered nickel thin films measured with Kelvin probe force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eren, B. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Material Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Gysin, U.; Marot, L., E-mail: Laurent.marot@unibas.ch; Glatzel, Th.; Steiner, R.; Meyer, E. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2016-01-25

    Few layer graphene and graphite are simultaneously grown on a ∼100 nm thick polycrystalline nickel film. The work function of few layer graphene/Ni is found to be 4.15 eV with a variation of 50 meV by local measurements with Kelvin probe force microscopy. This value is lower than the work function of free standing graphene due to peculiar electronic structure resulting from metal 3d-carbon 2p(π) hybridization.

  8. Sub-milliKelvin spatial thermometry of a single Doppler cooled ion in a Paul trap

    OpenAIRE

    Knünz, S.; Herrmann, M; Batteiger, V.; Saathoff, G.; Hänsch, T. W.; Udem, Th.

    2012-01-01

    We report on observations of thermal motion of a single, Doppler-cooled ion along the axis of a linear radio-frequency quadrupole trap. We show that for a harmonic potential the thermal occupation of energy levels leads to Gaussian distribution of the ion's axial position. The dependence of the spatial thermal spread on the trap potential is used for precise calibration of our imaging system's point spread function and sub-milliKelvin thermometry. We employ this technique to investigate the l...

  9. Sub-milliKelvin spatial thermometry of a single Doppler cooled ion in a Paul trap

    CERN Document Server

    Knünz, S; Batteiger, V; Saathoff, G; Hänsch, T W; Udem, Th; 10.1103/PhysRevA.85.023427

    2012-01-01

    We report on observations of thermal motion of a single, Doppler-cooled ion along the axis of a linear radio-frequency quadrupole trap. We show that for a harmonic potential the thermal occupation of energy levels leads to Gaussian distribution of the ion's axial position. The dependence of the spatial thermal spread on the trap potential is used for precise calibration of our imaging system's point spread function and sub-milliKelvin thermometry. We employ this technique to investigate the laser detuning dependence of the Doppler temperature.

  10. COMPENSATION OF MEASUREMENT ERRORS WHEN REDUCING LINEAR DIMENSIONS OF THE KELVIN PROBE

    Directory of Open Access Journals (Sweden)

    A. K. Tyavlovsky

    2013-01-01

    Full Text Available The study is based on results of modeling of measurement circuit containing vibrating-plate capacitor using a complex-harmonic analysis technique. Low value of normalized frequency of small-sized scanning Kelvin probe leads to high distortion factor of probe’s measurement signal that in turn leads to high measurement errors. The way to lower measurement errors is to register measurement signal on its second harmonic and to control the probe-to-sample gap by monitoring the ratio between the second and the first harmonics’ amplitudes.

  11. EFFECT OF DUST CHARGE FLUCTUATIONS ON KELVIN-HELMHOLTZ INSTABILITY IN A COLD DUST PLASMA

    Institute of Scientific and Technical Information of China (English)

    Lu Li; Li Zhongyuan; Liu Zhenxing

    2000-01-01

    Effect of dust charge fluctuations on Kelvin-Helmholtz (K-H) instability driven by sheared dust flow is investigated in magnetised three-component cold dusty plasma. It is found that the dust charge fluctuations have little effect on the tenuous dust plasma in low-frequency perturbation. For a dense dust plasma, the maximum damping rate of the perturbed wave due to dust charge fluctuations will reach the order of dusty charging frequency. It will affect the existence of the K-H instability in the long wave length perturbation.

  12. Investigation of the depletion layer by scanning capacitance force microscopy with Kelvin probe force microscopy

    Science.gov (United States)

    Uruma, Takeshi; Satoh, Nobuo; Yamamoto, Hidekazu

    2016-08-01

    We have developed a scanning probe microscope (SPM) that combines atomic force microscopy (AFM) with both Kelvin probe force microscopy (KFM — to measure the surface potential) and scanning capacitance force microscopy (SCFM — to measure the differential capacitance). The surface physical characteristics of a commercial Si Schottky barrier diode (Si-SBD), with and without an applied reverse bias, were measured over the same area by our AFM/KFM/SCFM system. We thus investigated the discrete power device by calculating the depletion-layer width and drawing an energy-band diagram.

  13. Mixed initial-boundary value problem for equations of motion of Kelvin-Voigt fluids

    Science.gov (United States)

    Baranovskii, E. S.

    2016-07-01

    The initial-boundary value problem for equations of motion of Kelvin-Voigt fluids with mixed boundary conditions is studied. The no-slip condition is used on some portion of the boundary, while the impermeability condition and the tangential component of the surface force field are specified on the rest of the boundary. The global-in-time existence of a weak solution is proved. It is shown that the solution is unique and depends continuously on the field of external forces, the field of surface forces, and initial data.

  14. Stability for the Timoshenko Beam System with Local Kelvin-Voigt Damping

    Institute of Scientific and Technical Information of China (English)

    Hong Liang ZHAO; Kang Sheng LIU; Chun Guo ZHANG

    2005-01-01

    In this paper, we consider a vibrating beam with one segment made of viscoelastic material of a Kelvin-Voigt (shorted as K-V) type and other parts made of elastic material by means of the Timoshenko model. We have deduced mathematical equations modelling its vibration and studied the stability of the semigroup associated with the equation system. We obtain the exponential stability under certain hypotheses of the smoothness and structural condition of the coefficients of the system,and obtain the strong asymptotic stability under weaker hypotheses of the coefficients.

  15. Measuring Method of a Surface Property inside the Pore: Application of Kelvin's equation

    CERN Document Server

    Amano, Ken-ichi

    2015-01-01

    Surface analyses inside the nanopore, micropore, and a very narrow pipe are important topics for development of the chemical engineering. Here, we propose a measuring method which evaluates the surface coverage of the chemically modified pore surface and the corrosion rate of the inner surface of the narrow pipe, etc. The method uses Kelvin's equation that expresses saturated vapor pressure of a liquid in the pore (pipe). The surface coverage and the corrosion rate are calculated by measuring saturated vapor pressure of the liquid in the pore and the pipe, respectively. In this letter, we explain the concept of the method briefly.

  16. Developmental effects of 3,4-methylenedioxymethamphetamine: a review

    OpenAIRE

    Skelton, Matthew R.; Williams, Michael T; Vorhees, Charles V.

    2008-01-01

    ± 3,4-Methylenedioxymethamphetamine (MDMA) is a chemical derivative of amphetamine that has become a popular drug of abuse and has been shown to deplete serotonin in the brains of users and animals exposed to it. To date, most studies have investigated the effects of MDMA on adult animals. With a majority of users of MDMA being young adults, the chances of the users becoming pregnant and exposing the fetuses to MDMA are also a concern. Evidence to date has shown that developmental exposure to...

  17. 3,4-Diaminopyridinium 2-carboxy-4,6-dinitrophenolate

    Directory of Open Access Journals (Sweden)

    Madhukar Hemamalini

    2010-11-01

    Full Text Available In the title salt, C5H8N3+·C7H3N2O7−, the pyridine N atom of the 3,4-diaminopyridine molecule is protonated. The 3,5-dinitrosalicylate anion shows whole-molecule disorder over two orientations with a refined occupancy ratio of 0.875 (4: 0.125 (4. In the crystal, the cations and anions are connected by intermolecular N—H...O and C—H...O hydrogen bonds, forming a three-dimensional network.

  18. Stereoselective Synthesis of 2,3,4,6-Tetrasubstituted Tetrahydropyrans

    Institute of Scientific and Technical Information of China (English)

    GONG Jun-Fang; WU Yang-Jie; Véronique Micheletb; Jean-Pierre Genêt b

    2003-01-01

    @@ The construction of stereodefined, highly substituted tetrahydropyrans has attracted a lot of interest over the years since they constitute ubiquitous fragments of numerous biologically active natural products.[1] During the course of our synthetic studies toward ambruticin, a fascinating antibiotic[2] which came back in the front scene with three recent total synthesis, [3] we have been interested in the synthesis of 2,3,4,6-tetrasubstituted tetrahydropyrans 5 (Scheme 1). [4] Moreover, this kind of subunit is found to be embedded in several other natural products such as lasonolide A, polycavernoside A, ratjadone, or concanamycin A.

  19. AGR 3/4 Irradiation Test Final As Run Report

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    Several fuel and material irradiation experiments have been planned for the Idaho National Laboratory Advanced Reactor Technologies Technology Development Office Advanced Gas Reactor Fuel Development and Qualification Program (referred to as the INL ART TDO/AGR fuel program hereafter), which supports the development and qualification of tristructural-isotropic (TRISO) coated particle fuel for use in HTGRs. The goals of these experiments are to provide irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, support development and validation of fuel performance and fission product transport models and codes, and provide irradiated fuel and materials for post irradiation examination and safety testing (INL 05/2015). AGR-3/4 combined the third and fourth in this series of planned experiments to test TRISO coated low enriched uranium (LEU) oxycarbide fuel. This combined experiment was intended to support the refinement of fission product transport models and to assess the effects of sweep gas impurities on fuel performance and fission product transport by irradiating designed-to-fail fuel particles and by measuring subsequent fission metal transport in fuel-compact matrix material and fuel-element graphite. The AGR 3/4 fuel test was successful in irradiating the fuel compacts to the burnup and fast fluence target ranges, considering the experiment was terminated short of its initial 400 EFPD target (Collin 2015). Out of the 48 AGR-3/4 compacts, 42 achieved the specified burnup of at least 6% fissions per initial heavy-metal atom (FIMA). Three capsules had a maximum fuel compact average burnup < 10% FIMA, one more than originally specified, and the maximum fuel compact average burnup was <19% FIMA for the remaining capsules, as specified. Fast neutron fluence fell in the expected range of 1.0 to 5.5×1025 n/m2 (E >0.18 MeV) for all compacts. In addition, the AGR-3/4 experiment was globally successful in keeping the

  20. 34 CFR 300.11 - Day; business day; school day.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Day; business day; school day. 300.11 Section 300.11 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION...

  1. [Assessment of the in vitro and in vivo toxicity of 3,4-dihydroxyphenylacetaldehyde (DOPAL)].

    Science.gov (United States)

    Bonnet, J-J; Legros, H; Janin, Fr; Dourmap, N; Costentin, J

    2004-09-01

    This work was carried out in order to evaluate the in vitro and in vivo toxicity of 3,4-dihydroxyphenylacetaldehyde (DOPAL). This aldehyde is formed from dopamine (DA) by monoamine oxidases (MAO) and is mainly oxidised to 3,4-dihydroxyphenylacetic acid by brain aldehyde dehydrogenases (ALDH), or eventually reduced to 3,4-dihydroxyphenylethanol by aldose/aldehyde reductases. In vitro, catecholaminergic SH-SY5Y cells were incubated with DA and disulfiram (DSF), an irreversible inhibitor of ALDH. As evidenced by MTT assays, a 24-h treatment with 10(-4) M DA and/or 10(-6) M DSF followed by a 24-h incubation in a drug-free medium evidenced that the toxicity of each of these drugs was potentiated by the second drug. HPLC measurements demonstrated that this drug association induced an early DOPAL production that could result in a delayed cell toxicity. For in vivo studies, male Sprague-Dawley rats were treated with L-DOPA-benserazide, which increases the production of DOPAL by MAO, and DSF. An acute injection of DSF (100mg/kg i.p.) and L-DOPA/benserazide (100mg/kg+25mg/kg, 24h later) significantly increased the DOPAL striatal level. However, a 30-day treatment with DSF (100mg/kg i.p., once every two days) and L-DOPA/benserazide (100mg/kg+25mg/kg, twice a day) did not affect both indexes used to assess the integrity of the nigro-striatal dopaminergic terminals (i.e. the striatal content in DA and the binding to the vesicular monoamine transporter on striatal membranes). These results do not support the hypothesis of a DOPAL toxicity and argue against the toxicity of L-DOPA therapy.

  2. Synthesis of 4-aryl-3,4-dihydrocoumarin derivatives catalyzed by NbCl{sub 5}; Sintese de derivados 4-aril-3,4-di-hidrocuraminicos catalisada por NbCl{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Willian Henrique dos; Siqueira, Mayara de Souza; Silva-Filho, Luiz Carlos da, E-mail: lcsilva@fc.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Bauru, SP (Brazil). Faculdade de Ciencias

    2013-11-01

    Multicomponent reactions between phenols, {beta}-diesters and benzaldehydes for the synthesis of 4-aryl-3,4-dihydrocoumarin derivatives were carried out under mild conditions (room temperature) and presented moderate yields (38-88%) and reasonable reaction times (2-4 days), using niobium pentachloride as a catalyst. (author)

  3. The Magnetohydrodynamic Kelvin-Helmholtz Instability A Three-Dimensional Study of Nonlinear Evolution

    CERN Document Server

    Ryu, D; Frank, A I; Ryu, Dongsu; Frank, Adam

    2000-01-01

    We investigate through high resolution 3D simulations the nonlinear evolution of compressible magnetohydrodynamic flows subject to the Kelvin-Helmholtz instability. We confirm in 3D flows the conclusion from our 2D work that even apparently weak magnetic fields embedded in Kelvin-Helmholtz unstable plasma flows can be fundamentally important to nonlinear evolution of the instability. In fact, that statement is strengthened in 3D by this work, because it shows how field line bundles can be stretched and twisted in 3D as the quasi-2D Cat's Eye vortex forms out of the hydrodynamical motions. In our simulations twisting of the field may increase the maximum field strength by more than a factor of two over the 2D effect. If, by these developments, the Alfv\\'en Mach number of flows around the Cat's Eye drops to unity or less, our simulations suggest magnetic stresses will eventually destroy the Cat's Eye and cause the plasma flow to self-organize into a relatively smooth and apparently stable flow that retains memo...

  4. Study of the Kelvin-Helmholtz instability through simulation with the code Athena

    CERN Document Server

    Freitas-Lemes, P; Faúndez-Abans, M

    2013-01-01

    Kelvin-Helmholtz instabilities are common in astrophysical systems, ranging from jet black holes up to protoplanetary accretion disk. An astrophysical object with strong characteristics of the Kelvin-Helmholtz instability is Caraguejo Nebula, in which the material expansion was caused by the explosion of a supernova about 1000 years ago. This instability occurs at the boundary between two fluids of different densities when one of the fluids accelerated with respect to the other. In order to study this instability, we performed a simulation with the code ATHENA Eulerian mesh. For this simulation, we consider a square domain with periodic boundaries on the sides, and reflecting on the boundary of the top and bottom. The upper box is filled with a gas density {\\rho}=1.0, pressure P1 = 1.0, adiabatic index {\\gamma}=5/3, and velocity u1=0.03 in the x direction (to the right). The lower portion has a density {\\rho}=2.0, the same pressure, velocity, and adiabatic index, only in the opposite direction to the left. Sp...

  5. Interaction of Kelvin force and transport across a melting substrate in a microgravity environment.

    Science.gov (United States)

    Burgess, Nicholas K; Premnath, Kannan N

    2010-10-01

    Gradients in magnetic field applied to electrically insulating fluids result in an effective body force-the Kelvin force, which can potentially be used to control flow and thermal processes, particularly in microgravity environments. We study the influence of the Kelvin force on the mass, momentum, and energy transport of fluid arising from the melting of a semi-infinite solid substrate subjected to temperature and magnetic-field gradients. The governing equations of the magnetothermal free convection of the melt under the boundary layer approximation with a suitable transformation lead to a similarity solution. Closed-form analytical solutions for the limiting case of smaller Prandtl numbers are presented. The nonlinear similarity equations are solved numerically using an iterative boundary-value technique based on a finite-difference approach. Based on the numerical results, the effect of various characteristic nondimensional parameters on the structure of the melt boundary layer and transport rates of heat and mass across the substrate are elucidated and discussed. PMID:21230386

  6. Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization.

    Directory of Open Access Journals (Sweden)

    Bertrand Jóźwiak

    Full Text Available The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2. The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G' and G" and shear creep compliance J(t. It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process.

  7. Observation of equatorial Kelvin solitary waves in a slowly varying thermocline

    Directory of Open Access Journals (Sweden)

    Q. Zheng

    1998-01-01

    Full Text Available TOPEX/POSEIDON (T/P sea level deviation (SLD time series from 3 October 1992 to 15 May 1997 combined with upper ocean thermal structures are used to observe the characteristics and analyze the dynamics of equatorial waves in the Pacific Ocean. The evolution of the Kelvin wave propagating along an eastward shoaling thermocline in the equatorial Pacific is investigated. The behaviour of this wave as it propagates eastward can be approximately described with the solutions of the perturbed Korteweg-de Vries (PKDV equation and modified Green's Law. Assuming that the nonlinear term and dispersive term of this equation are balanced, the amplitude increases as the thermocline decreases to the power -3/8. Approaching the eastern Pacific, the nonlinearity increases and the relation changes to the power -9/8. The dispersion relation, and mass and energy conservations are investigated. The results indicate that under a varying thermocline, the nonlinear Kelvin solitary waves indeed exist in the real ocean.

  8. Excitation of equatorial Kelvin and Yanai waves by tropical cyclones in an ocean general circulation model

    Directory of Open Access Journals (Sweden)

    R. L. Sriver

    2013-01-01

    Full Text Available Tropical cyclones (TCs actively contribute to the dynamics of Earth's coupled climate system. They influence oceanic mixing rates, upper-ocean heat content, and air–sea fluxes, with implications for atmosphere and ocean dynamics on multiple spatial and temporal scales. Using an ocean general circulation model with modified surface wind forcing, we explore how TC winds can excite equatorial ocean waves in the tropical Pacific. We highlight a situation where three successive TCs in the western North Pacific region, corresponding to events in 2003, excite a combination of Kelvin and Yanai waves in the equatorial Pacific. The resultant thermocline adjustment significantly modifies the thermal structure of the upper equatorial Pacific and leads to eastward zonal heat transport. Observations of upper-ocean temperature by the Tropical Atmosphere Ocean (TAO buoy array and sea-level height anomalies using altimetry reveal wave passage during the same time period with similar properties to the modeled wave, although our idealized model methodology disallows precise identification of the TC forcing with the observed waves. Results indicate that direct oceanographic forcing by TCs may be important for understanding the spectrum of equatorial ocean waves, thus remotely influencing tropical mixing and surface energy budgets. Because equatorial Kelvin waves are closely linked to interannual variability in the tropical Pacific, these findings also suggest TC wind forcing may influence the timing and amplitude of El Niño events.

  9. Excitation of equatorial Kelvin and Yanai waves by tropical cyclones in an ocean general circulation model

    Directory of Open Access Journals (Sweden)

    R. L. Sriver

    2012-09-01

    Full Text Available Tropical cyclones (TCs actively contribute to the dynamics of Earth's coupled climate system. They influence oceanic mixing rates, upper-ocean heat content, and air-sea fluxes, with implications for atmosphere and ocean dynamics on multiple spatial and temporal scales. Using an ocean general circulation model with modified surface wind forcing, we explore how TC winds can excite equatorial ocean waves in the tropical Pacific. We highlight a situation where three successive TCs in the western North Pacific region, corresponding to events in 2003, excite a combination of Kelvin and Yanai waves in the equatorial Pacific. The resultant thermocline adjustment significantly modifies the thermal structure of the upper equatorial Pacific and leads to eastward zonal heat transport. Observations of upper-ocean temperature by the Tropical Atmosphere Ocean (TAO buoy array and sea-level height anomalies using altimetry reveal wave passage during the same time period with similar properties to the modeled wave, although our idealized model methodology disallows precise identification of the TC forcing with the observed waves. Results indicate that direct oceanographic forcing by TCs may be important for understanding the spectrum of equatorial ocean waves, thus remotely influencing tropical mixing and surface energy budgets. Because equatorial Kelvin waves are closely linked to interannual variability in the tropical Pacific, these findings also suggest TC wind forcing may influence the timing and amplitude of El Niño events.

  10. Two competing interpretations of Kelvin probe force microscopy on semiconductors put to test

    Science.gov (United States)

    Polak, Leo; Wijngaarden, Rinke J.

    2016-05-01

    Kelvin probe force microscopy (KPFM) is a popular tool for studying properties of semiconductors. However, the interpretation of its results is complicated by the possibility of so-called band bending and the presence of surface charges. In this work, we study two different interpretations for KPFM on semiconductors: the contact potential difference (CPD) interpretation, which interprets the measured potential as the work-function difference between the sample and the probe, and a newer, alternative interpretation proposed by Baumgart, Helm, and Schmidt (BHS). By performing model calculations, we demonstrate that these models generally lead to very different results. Hence it is important to decide which one is correct. We demonstrate that BHS predictions for the Kelvin voltage difference between the p and n parts of a p n junction are inconsistent with a set of experimental results from the literature. In addition, the BHS interpretation predicts an independence from the probe material as well as from surface treatments, which we both find to disagree with experiment. On the other hand, we present a theoretical argument for the validity of the CPD interpretation and we show that the CPD interpretation is able to accommodate all of these experimental results. Thus we posit that the BHS interpretation is generally not suitable for the analysis of KPFM on semiconductors and that the CPD interpretation should be used instead.

  11. Stability of rotating magnetized jets in the solar atmosphere. I. Kelvin-Helmholtz instability

    CERN Document Server

    Zaqarashvili, T V; Ofman, L

    2015-01-01

    Observations show various jets in the solar atmosphere with significant rotational motions, which may undergo instabilities leading to heat ambient plasma. We study the Kelvin-Helmholtz (KH) instability of twisted and rotating jets caused by the velocity jumps near the jet surface. We derive a dispersion equation with appropriate boundary condition for total pressure (including centrifugal force of tube rotation), which governs the dynamics of incompressible jets. Then, we obtain analytical instability criteria of Kelvin-Helmholtz instability in various cases, which were verified by numerical solutions to the dispersion equation. We find that twisted and rotating jets are unstable to KH instability when the kinetic energy of rotation is more than the magnetic energy of the twist. Our analysis shows that the azimuthal magnetic field of 1-5 G can stabilize observed rotations in spicule/macrospicules and X-ray/EUV jets. On the other hand, non-twisted jets are always unstable to KH instability. In this case, the ...

  12. Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization.

    Science.gov (United States)

    Jóźwiak, Bertrand; Orczykowska, Magdalena; Dziubiński, Marek

    2015-01-01

    The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G' and G" and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process. PMID:26599756

  13. Kelvin-Helmholtz instability for a bounded plasma flow in a longitudinal magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Burinskaya, T. M.; Shevelev, M. M. [Russian Academy of Sciences, Space Research Institute (Russian Federation); Rauch, J.-L. [Centre National de la Recherche Scientifique, Laboratoire de Physique et Chimie de l' Environnement et de l' Espace (France)

    2011-01-15

    Kelvin-Helmholtz MHD instability in a plane three-layer plasma is investigated. A general dispersion relation for the case of arbitrarily orientated magnetic fields and flow velocities in the layers is derived, and its solutions for a bounded plasma flow in a longitudinal magnetic field are studied numerically. Analysis of Kelvin-Helmholtz instability for different ion acoustic velocities shows that perturbations with wavelengths on the order of or longer than the flow thickness can grow in an arbitrary direction even at a zero temperature. Oscillations excited at small angles with respect to the magnetic field exist in a limited range of wavenumbers even without allowance for the finite width of the transition region between the flow and the ambient plasma. It is shown that, in a low-temperature plasma, solutions resulting in kink-like deformations of the plasma flow grow at a higher rate than those resulting in quasi-symmetric (sausage-like) deformations. The transverse structure of oscillatory-damped eigenmodes in a low-temperature plasma is analyzed. The results obtained are used to explain mechanisms for the excitation of ultra-low-frequency long-wavelength oscillations propagating along the magnetic field in the plasma sheet boundary layer of the Earth's magnetotail penetrated by fast plasma flows.

  14. Pressure Corrections for the Potential Flow Analysis of Electrohydrodynamic Kelvin-Helmholtz Instability

    Directory of Open Access Journals (Sweden)

    Awasthi Mukesh Kumar

    2015-01-01

    Full Text Available The present paper deals with the study of the pressure corrections to the viscous potential flow analysis of Kelvin-Helmholtz instability with tangential electric field at the interface of two viscous fluids. Viscosity enters through normal stress balance in the viscous potential flow theory and tangential stresses for two fluids are not continuous at the interface. Here we have considered viscous pressure in the normal stress balance along with the irrotational pressure and it is assumed that the addition of this viscous pressure will resolve the discontinuity between the tangential stresses and the tangential velocities at the interface of two fluids. The viscous pressure is derived by mechanical energy balance equation and this pressure correction applied to compute the growth rate of electrohydrodynamic Kelvin-Helmholtz instability. A dispersion relation is obtained and stability criterion is given in the terms of critical value of relative velocity. It has been observed that the inclusion of irrotational shearing stresses have stabilizing effect on the stability of the system.

  15. Ultraporous poly(3,4-ethylenedioxythiophene) for nanometric electrochemical supercapacitor

    International Nuclear Information System (INIS)

    Ultrathin films of poly(3,4-ethylenedioxythiophene) (PEDOT) have been prepared by electropolymerization on steel and indium-tin oxide (ITO) substrates under identical experimental conditions. Scanning electron microscopy and atomic force microscopy indicate that the substrate affects dramatically both the morphology and topography of films when the polymerization times are very short. An ultraporous three-dimensional network involving ultrathin sticks with a fiber-like morphology was formed on ITO. Asymmetric and symmetric supercapacitors have been fabricated by assembling electrodes of PEDOT deposited on ITO and steel. The specific capacitance, electrochemical stability, supercapacitor behavior and Coulombic efficiency measured for devices with an ITO/steel configuration were similar to those reported for advanced PEDOT-inorganic hybrid composites. Furthermore, the performance of the ITO/steel assembly is higher than those determined for symmetric supercapacitors derived from two identical electrodes of PEDOT deposited on steel or on ITO. The unique properties of the asymmetric supercapacitors have been attributed to the ultraporous structure of the ultrathin films deposited on ITO, which is not significantly perturbed when the device is submitted to a very high number of consecutive oxidation–reduction processes, and the different electroactivities of the two electrodes. - Highlights: ► Ultrathin poly(3,4-ethylenedioxythiophene) (PEDOT) films show fiber-like morphology. ► The porosity of ultrathin PEDOT films induces a very high electrochemical stability. ► Asymmetric supercapacitors made of ultrathin PEDOT behave like hybrid nanocomposites.

  16. Chronic Unpredictable Stress Augments +3,4-Methylenedioxymethamphetamine (MDMA)-induced Monoamine Depletions: The Role of Corticosterone

    OpenAIRE

    Johnson, Bethann N.; Yamamoto, Bryan K.

    2009-01-01

    Exposure to stress alters the behavioral and neurochemical effects of drugs of abuse. However, it is unknown if chronic stress can affect the serotonergic depletions induced by the psychostimulant drug 3,4-methylenedioxymethamphetamine (MDMA). Rats were exposed to 10 days of chronic unpredictable stress (CUS) which resulted in the predicted elevation of basal plasma corticosterone concentrations. On the 11th day, rats received 4 challenge doses of MDMA (5 mg/kg every 2 h, i.p.) or saline. Fiv...

  17. Uncertainty Quantification of Calculated Temperatures for the AGR 3/4 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh Thi-Cam [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    A series of Advanced Gas Reactor (AGR) irradiation experiments are being conducted within the Advanced Reactor Technology (ART) Fuel Development and Qualification Program. The main objectives of the fuel experimental campaign are to provide the necessary data on fuel performance to support fuel process development, qualify a fuel design and fabrication process for normal operation and accident conditions, and support development and validation of fuel performance and fission product transport models and codes (PLN 3636, “Technical Program Plan for INL Advanced Reactor Technologies Technology Development Office/Advanced Gas Reactor Fuel Development and Qualification Program”). The AGR 3/4 test was inserted in the Northeast Flux Trap position in the Advanced Test Reactor (ATR) core at Idaho National Laboratory (INL) in December 2011 and successfully completed irradiation in mid-April 2014, resulting in irradiation of the tristructural isotropic (TRISO) fuel for 369.1 effective full-power days (EFPDs) during approximately 2.4 calendar years. The AGR 3/4 data, including the irradiation data and calculated results, were qualified and stored in the Nuclear Data Management and Analysis System (NDMAS). To support the U.S. TRISO fuel performance assessment and to provide data for validation of fuel performance and fission product transport models and codes, the daily as run thermal analysis has been performed separately on each of twelve AGR 3/4 capsules for the entire irradiation as discussed in ECAR-2807, “AGR 3/4 Daily As Run Thermal Analyses”. The ABAQUS code’s finite element-based thermal model predicts the daily average volume average (VA) fuel temperature (FT), peak FT, and graphite matrix, sleeve, and sink temperature in each capsule. The JMOCUP simulation codes were also created to perform depletion calculations for the AGR 3/4 experiment (ECAR-2753, “JMOCUP As-Run Daily Physics Depletion Calculation for the AGR 3/4 TRISO Particle Experiment in ATR

  18. Uncertainty Quantification of Calculated Temperatures for the AGR 3/4 Experiment

    International Nuclear Information System (INIS)

    A series of Advanced Gas Reactor (AGR) irradiation experiments are being conducted within the Advanced Reactor Technology (ART) Fuel Development and Qualification Program. The main objectives of the fuel experimental campaign are to provide the necessary data on fuel performance to support fuel process development, qualify a fuel design and fabrication process for normal operation and accident conditions, and support development and validation of fuel performance and fission product transport models and codes (PLN 3636, 'Technical Program Plan for INL Advanced Reactor Technologies Technology Development Office/Advanced Gas Reactor Fuel Development and Qualification Program'). The AGR 3/4 test was inserted in the Northeast Flux Trap position in the Advanced Test Reactor (ATR) core at Idaho National Laboratory (INL) in December 2011 and successfully completed irradiation in mid-April 2014, resulting in irradiation of the tristructural isotropic (TRISO) fuel for 369.1 effective full-power days (EFPDs) during approximately 2.4 calendar years. The AGR 3/4 data, including the irradiation data and calculated results, were qualified and stored in the Nuclear Data Management and Analysis System (NDMAS). To support the U.S. TRISO fuel performance assessment and to provide data for validation of fuel performance and fission product transport models and codes, the daily as run thermal analysis has been performed separately on each of twelve AGR 3/4 capsules for the entire irradiation as discussed in ECAR-2807, 'AGR 3/4 Daily As Run Thermal Analyses'. The ABAQUS code's finite element-based thermal model predicts the daily average volume average (VA) fuel temperature (FT), peak FT, and graphite matrix, sleeve, and sink temperature in each capsule. The JMOCUP simulation codes were also created to perform depletion calculations for the AGR 3/4 experiment (ECAR-2753, 'JMOCUP As-Run Daily Physics Depletion Calculation for the AGR 3/4 TRISO Particle

  19. 2′,3,4,4′-Tetramethoxychalcone

    Directory of Open Access Journals (Sweden)

    Johannes H. van Tonder

    2010-07-01

    Full Text Available In the title compound [systematic name: 1-(2,4-dimethoxyphenyl-3-(3,4-dimethoxyphenylprop-2-en-1-one], C19H20O5, the dihedral angle between the benzene rings is 26.88 (5°. One of the methoxy groups is twisted slightly away from the plane [C—O—C—C torsion angle = −12.8 (3°] while the others are almost co-planer [C—O—C—C torsion angles = −3.2 (3, 2.6 (3 and −3.6 (3°]. The crystal packing is stabilized by intermolecular C—H...O interactions. A weak intramolecular C—H...O interaction occurs.

  20. Satellite observations of the QBO wave driving by Kelvin waves and gravity waves

    Science.gov (United States)

    Ern, Manfred; Preusse, Peter; Kalisch, Silvio; Riese, Martin

    2014-05-01

    The quasi-biennial oscillation (QBO) of the zonal wind in the tropical stratosphere is an important process in atmospheric dynamics influencing a wide range of altitudes and latitudes. Effects of the QBO are found also in the mesosphere and in the extra-tropics. The QBO even has influence on the surface weather and climate, for example during winter in the northern hemisphere at midlatitudes. Still, climate models have large difficulties in reproducing a realistic QBO. One reason for this deficiency are uncertainties in the wave driving by planetary waves and, in particular, gravity waves that are usually too small-scale to be resolved in global models. Different global equatorial wave modes (e.g., Kelvin waves) have been identified by longitude-time 2D spectral analysis in Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite temperature data, as well as ECMWF temperatures. We find good agreement between SABER satellite observations and ECMWF wave variances in both QBO-related temporal variations and their magnitude. Slow phase speed waves are strongly modulated by the QBO, higher phase speed waves are almost unaffected by the QBO, and ultra-fast equatorial waves can even reach the MLT region. Momentum fluxes and zonal wind drag due to Kelvin waves are derived, and the relative contribution of Kelvin waves to the QBO wind reversal from westward to eastward wind is estimated to be about 30% of the total wave driving. This is in good agreement with the general assumption that gravity waves (GWs) are probably more important for the QBO driving than global-scale waves. This is further supported by SABER and High Resolution Dynamics Limb Sounder (HIRDLS) satellite observations of gravity wave drag in the equatorial region. These observations are compared with the drag still missing in the ECMWF ERA Interim (ERAI) tropical momentum budget after considering zonal wind tendency, Coriolis force, advection terms and drag of resolved global

  1. Finite Element Modelling of Infinite Euler Beams on Kelvin Foundations Exposed to Moving Loads in Convected Co-ordinates

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R.K.; Kirkegaard, Poul Henning

    2001-01-01

    The paper deals with the finite element method (FEM) solution of the problem with loads moving uniformly along an infinite Euler beam supported by a linear elastic Kelvin foundation with linear viscous damping. Initially, the problem is formulatedin a moving co-ordinate system following the load...

  2. Seasonal occurrence of sperm whales (Physeter macrocephalus) around Kelvin Seamount in the Sargasso Sea in relation to oceanographic processes

    Science.gov (United States)

    Wong, Sarah N. P.; Whitehead, Hal

    2014-09-01

    Sperm whales (Physeter macrocephalus) are widely distributed in all oceans, but they are clumped geographically, generally in areas associated with high primary and secondary productivity. The warm, clear waters of the Sargasso Sea are traditionally thought to be low in productivity, however recent surveys have found large numbers of sperm whales there. The New England Seamount Chain bisects the north-western portion of the Sargasso Sea, and might influence the mesoscale eddies associated with the Gulf Stream; creating areas of higher productivity within the Sargasso Sea. We investigated the seasonal occurrence of sperm whales over Kelvin Seamount (part of the New England Seamount Chain) and how it is influenced by oceanographic variables. An autonomous recording device was deployed over Kelvin Seamount from May to June 2006 and November 2006 to June 2007. A total of 6505 hourly two-minute recordings were examined for the presence of sperm whale echolocation clicks. Sperm whales were more prevalent around Kelvin in the spring (April to June: mean=51% of recordings contained clicks) compared to the winter (November to March: mean=16% of recordings contained clicks). Sperm whale prevalence at Kelvin was related to chlorophyll-a concentration four weeks previous, eddy kinetic energy and month. The mesoscale activity associated with the Gulf Stream and the Gulf Stream's interaction with the New England Seamount Chain likely play an important role in sperm whale occurrence in this area, by increasing productivity and perhaps concentration of cephalopod species.

  3. Numerical simulations of the Kelvin-Helmholtz instability with the Gadget-2 SPH code

    CERN Document Server

    Gabbasov, Ruslan F; Suarez-Cansino, Joel; Sigalotti, Leonardo Di G

    2013-01-01

    The method of Smoothed Particle Hydrodynamics (SPH) has been widely studied and implemented for a large variety of problems, ranging from astrophysics to fluid dynamics and elasticity problems in solids. However, the method is known to have several deficiencies and discrepancies in comparison with traditional mesh-based codes. In particular, there has been a discussion about its ability to reproduce the Kelvin-Helmholtz Instability in shearing flows. Several authors reported that they were able to reproduce correctly the instability by introducing some improvements to the algorithm. In this contribution, we compare the results of Read et al. (2010) implementation of the SPH algorithm with the original Gadget-2 N-body/SPH code.

  4. Kelvin-Helmootz instability of double perturbed cylindrical self-gravitating fluids

    International Nuclear Information System (INIS)

    The Kelvin-Helmholtz instability of a self-gravitating gas cylinder (radius R and density ρ(1), co-axial with a perturbed fluid cylinder (density ρ(2) and radius q R with 1 (2) = 0 is obtained as a limiting case. Here the streaming has a strong destabilizing effect. As U = 0, the marginal stability occurred as ρ(1) = ρ(2). While as U ≠ 0, the marginal stability states do not occur at ρ(1) = ρ(2). As q values are increased for the case 0 (2)/ρ(1) (1) (2), the principle of exchange of instability is valid for the most cases especially for large values of q. The result is (physically interpreted) related to the behavior of the spiral arm of galaxy.

  5. Scanning Kelvin-probe study of the hydrogen-terminated diamond surface in ultrahigh vacuum

    International Nuclear Information System (INIS)

    Atomic-force and Kelvin-probe microscopies were employed in ultrahigh vacuum to image the surface topography and contact potential of the hydrogen-terminated and unterminated surfaces of diamond. A variation of about 25 meV in the contact potential was measured on a length scale of 20 nm and ascribed to differently orientated surface domains resulting from hydrogen-plasma processing of the sample. Shifts in the work function arising from sample heating in vacuum and the adsorption of C60 were measured. The Fermi level was found to be 0.7 and 1.1 eV below the valence band maximum for C60 coverages of 1 and 4 monolayer, respectively.

  6. Kelvin-Helmholtz instability in solar chromospheric jets: theory and observation

    CERN Document Server

    Kuridze, D; Henriques, V; Mathioudakis, M; Keenan, F P; Hanslmeier, A

    2016-01-01

    Using data obtained by the high resolution CRisp Imaging SpectroPolarimeter instrument on the Swedish 1-m Solar Telescope, we investigate the dynamics and stability of quiet-Sun chromospheric jets observed at disk center. Small-scale features, such as Rapid Redshifted and Blueshifted Excursions, appearing as high speed jets in the wings of the H$\\alpha$ line, are characterized by short lifetimes and rapid fading without any descending behavior. To study the theoretical aspects of their stability without considering their formation mechanism, we model chromospheric jets as twisted magnetic flux tubes moving along their axis, and use the ideal linear incompressible magnetohydrodynamic approximation to derive the governing dispersion equation. Analytical solutions of the dispersion equation indicate that this type of jet is unstable to Kelvin-Helmholtz instability (KHI), with a very short (few seconds) instability growth time at high upflow speeds. The generated vortices and unresolved turbulent flows associated...

  7. Kelvin probe studies of cesium telluride photocathode for the AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez, D.; Wisniewski, E. E.; Yusof, Z.; Harkay, K.; Spentzouris, L.; Terry, J. [Physics Department at Illinois Institute of Technology, Chicago, IL 60616 and High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Accelerator Science Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Physics Department at Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2012-12-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (> 1%), is robust in a photoinjector, and long lifetime. This photocathode is fabricated in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch ({approx}50 nC) in a long bunch train. We present some results from a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV light exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  8. Bending vibration of axially loaded Timoshenko beams with locally distributed Kelvin-Voigt damping

    Science.gov (United States)

    Chen, Wei-Ren

    2011-06-01

    Utilizing the Timoshenko beam theory and applying Hamilton's principle, the bending vibration equations of an axially loaded beam with locally distributed internal damping of the Kelvin-Voigt type are established. The partial differential equations of motion are then discretized into linear second-order ordinary differential equations based on a finite element method. A quadratic eigenvalue problem of a damped system is formed to determine the eigenfrequencies of the damped beams. The effects of the internal damping, sizes and locations of damped segment, axial load and restraint types on the damping and oscillating parts of the damped natural frequency are investigated. It is believed that the present study is valuable for better understanding the influence of various parameters of the damped beam on its vibration characteristics.

  9. Thermal consolidation of porous medium with a rheological kelvin-voigt skeleton

    Science.gov (United States)

    Bartlewska-Urban, Monika; Strzelecki, Tomasz

    2012-10-01

    This study presents calculations results of thermal consolidation process of the porous medium with the rheological Kelvin-Voigt skeleton, obtained numerically with the use of Flex.PDE software. The investigated calculation scheme consisted of the porous column filled with a liquid. The vertical load was applied to the top surface of the column through a porous plate allowing the free flow of liquid through this surface. Numerical solution is based on compression of the sample at appropriately defined boundary conditions. The aim of this study was to describe the influence of external load and temperature gradient on the deformation tests progress at different values of three parameters: λ, rs and cv. The results obtained, in the context of further research, can also be used for the determination of the influence of other parameters of the state and model parameters on the process of thermo poroelasticity of Biot model with rheological skeleton.

  10. Lack of exponential stability to Timoshenko system with viscoelastic Kelvin-Voigt type

    Science.gov (United States)

    Malacarne, Andréia; Muñoz Rivera, Jaime Edilberto

    2016-06-01

    We study the Timoshenko systems with a viscoelastic dissipative mechanism of Kelvin-Voigt type. We prove that the model is analytical if and only if the viscoelastic damping is present in both the shear stress and the bending moment. Otherwise, the corresponding semigroup is not exponentially stable no matter the choice of the coefficients. This result is different to all others related to Timoshenko model with partial dissipation, which establish that the system is exponentially stable if and only if the wave speeds are equal. Finally, we show that the solution decays polynomially to zero as {t^{-1/2}} , no matter where the viscoelastic mechanism is effective and that the rate is optimal whenever the initial data are taken on the domain of the infinitesimal operator.

  11. Interaction of Kelvin waves and non-locality of the energy transfer in superfluids

    CERN Document Server

    Laurie, Jason; Nazarenko, Sergey; Rudenko, Oleksii

    2009-01-01

    We argue that the physics of interacting Kelvin Waves (KWs) is highly non-trivial and cannot be understood on the basis of pure dimensional reasoning only. A consistent theory of KWs turbulence in superfluids should be based on explicit knowledge of the details of their interactions. To achieve this, we present a detailed calculation and comprehensive analysis of the interaction coefficients for KWs, thereby fixing previous mistakes stemming from unaccounted contributions. As a first application of this analysis, we show that the previously suggested Kozik-Svistunov energy spectrum of KWs, which has been often used for analysis of experimental and numerical data in superfluid turbulence, is irrelevant, because it is based on an erroneous assumption of the locality of the energy transfer through scales. We also demonstrate weak non-locality of the inverse cascade spectrum with a constant particle-number flux and find resulting logarithmic corrections to this spectrum.

  12. Accurate determination of the Boltzmann constant by Doppler spectroscopy: Towards a new definition of the kelvin

    CERN Document Server

    Darquié, Benoît; Sow, Papa Lat Tabara; Lemarchand, Cyril; Triki, Meriam; Tokunaga, Sean; Bordé, Christian J; Chardonnet, Christian; Daussy, Christophe

    2015-01-01

    Accurate molecular spectroscopy in the mid-infrared region allows precision measurements of fundamental constants. For instance, measuring the linewidth of an isolated Doppler-broadened absorption line of ammonia around 10 $\\mu$m enables a determination of the Boltzmann constant k B. We report on our latest measurements. By fitting this lineshape to several models which include Dicke narrowing or speed-dependent collisional effects, we find that a determination of k B with an uncertainty of a few ppm is reachable. This is comparable to the best current uncertainty obtained using acoustic methods and would make a significant contribution to any new value of k B determined by the CODATA. Furthermore, having multiple independent measurements at these accuracies opens the possibility of defining the kelvin by fixing k B, an exciting prospect considering the upcoming redefinition of the International System of Units.

  13. Study on magnetohydrodynamic Kelvin-Helmholtz instability with mass transfer through porous media

    Science.gov (United States)

    Kumar Awasthi, Mukesh

    2013-09-01

    We study the linear analysis of Kelvin-Helmholtz instability of the interface between two viscous and magnetic fluids in a fully saturated porous medium using viscous potential flow theory, when the fluids are subjected to a constant tangential magnetic field, and when there is heat and mass transfer across the interface. The Darcy-Brinkman model has been used for the investigation. A dispersion relation has been derived and stability is discussed theoretically as well as numerically. The stability criterion is given in terms of a critical value of relative velocity as well as the critical value of applied magnetic field. It has been observed that both tangential magnetic field and vapor fraction have stabilizing effect on the stability of the system while heat and mass transfer destabilizes the interface. Porosity stabilizes the interface while the porous medium has destabilizing effect.

  14. Singularity formation on a fluid interface during the Kelvin-Helmholtz instability development

    CERN Document Server

    Zubarev, N M

    2014-01-01

    The dynamics of singularity formation on the interface between two ideal fluids is studied for the Kelvin-Helmholtz instability development within the Hamiltonian formalism. It is shown that the equations of motion derived in the small interface angle approximation (gravity and capillary forces are neglected) admit exact solutions in the implicit form. The analysis of these solutions shows that, in the general case, weak root singularities are formed on the interface in a finite time for which the curvature becomes infinite, while the slope angles remain small. For Atwood numbers close to unity in absolute values, the surface curvature has a definite sign correlated with the boundary deformation directed towards the light fluid. For fluids with comparable densities, the curvature changes its sign in a singular point. In the particular case of fluids with equal densities, the obtained results are consistent with those obtained by Moore based on the Birkhoff-Rott equation analysis.

  15. Application of Kelvin Probe to Studies of Fusion Reactor Materials under Irradiation

    Institute of Scientific and Technical Information of China (English)

    Luo Guangnan; K. Yamaguchi; T. Terai; M. Yamawaki

    2005-01-01

    Recently, the work function (WF) changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe (KP),under He ion irradiation in high energy (MeV) and / or low energy (500 eV) ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.

  16. Numerical simulations of magnetic Kelvin-Helmholtz instability at a twisted solar flux tube

    Science.gov (United States)

    Murawski, K.; Chmielewski, P.; Zaqarashvili, T. V.; Khomenko, E.

    2016-07-01

    The paper aims to study the response of a solar small-scale and weak magnetic flux tube to photospheric twisting motions. We numerically solve three-dimensional ideal magnetohydrodynamic equations to describe the evolution of the perturbation within the initially static flux tube, excited by twists in the azimuthal component of the velocity. These twists produce rotation of the magnetic field lines. Perturbation of magnetic field lines propagates upwardly, driving vertical and azimuthal flow as well as plasma compressions and rarefactions in the form of eddies. We conclude that these eddies result from the sheared azimuthal flow which seeds Kelvin-Helmholtz instability (KHI) between the flux tube and the ambient medium. Numerically obtained properties of the KHI confirm the analytical predictions for the occurrence of the instability.

  17. Onset of the Kelvin-Helmholtz instability in partially ionized magnetic flux tubes

    CERN Document Server

    Martínez-Gómez, David; Terradas, Jaume

    2015-01-01

    Context. Recent observations of solar prominences show the presence of turbulent flows that may be caused by Kelvin-Helmholtz instabilites (KHI). However, the observed flow velocities are below the classical threshold for the onset of KHI in fully ionized plasmas. Aims. We investigate the effect of partial ionization on the onset of KHI in dense and cool cylindrical magnetic flux tubes surrounded by a hotter and lighter environment. Methods. The linearized governing equations of a partially ionized two-fluid plasma are used to describe the behavior of small-amplitude perturbations superimposed on a magnetic tube with longitudinal mass flow. A normal mode analysis is performed to obtain the dispersion relation for linear incompressible waves. We focus on the appearance of unstable solutions and study the dependence of their growth rates on various physical parameters. An analytical approximation of the KHI linear growth rate for slow flows and strong ion-neutral coupling is obtained. An application to solar pr...

  18. Suppression mechanism of Kelvin-Helmholtz instability in compressible fluid flows

    Science.gov (United States)

    Karimi, Mona; Girimaji, Sharath S.

    2016-04-01

    The transformative influence of compressibility on the Kelvin-Helmholtz instability (KHI) at the interface between two fluid streams of different velocities is explicated. When the velocity difference is small (subsonic), shear effects dominate the interface flow dynamics causing monotonic roll-up of vorticity and mixing between the two streams leading to the KHI. We find that at supersonic speed differentials, compressibility forces the dominance of dilatational (acoustic) rather than shear dynamics at the interface. Within this dilatational interface layer, traveling pressure waves cause the velocity perturbations to become oscillatory. We demonstrate that the oscillatory fluid motion reverses vortex roll-up and segregates the two streams leading to KHI suppression. Analysis and illustrations of the compressibility-induced suppression mechanism are presented.

  19. Nonlinear evolution of the magnetized Kelvin-Helmholtz instability: from fluid to kinetic modeling

    CERN Document Server

    Henri, P; Califano, F; Pegoraro, F; Rossi, C; Faganello, M; Šebek, O; Trávníček, P M; Hellinger, P; Frederiksen, J T; Nordlund, Å; Markidis, S; Keppens, R; Lapenta, G

    2013-01-01

    The nonlinear evolution of collisionless plasmas is typically a multi-scale process where the energy is injected at large, fluid scales and dissipated at small, kinetic scales. Accurately modelling the global evolution requires to take into account the main micro-scale physical processes of interest. This is why comparison of different plasma models is today an imperative task aiming at understanding cross-scale processes in plasmas. We report here the first comparative study of the evolution of a magnetized shear flow, through a variety of different plasma models by using magnetohydrodynamic, Hall-MHD, two-fluid, hybrid kinetic and full kinetic codes. Kinetic relaxation effects are discussed to emphasize the need for kinetic equilibriums to study the dynamics of collisionless plasmas in non trivial configurations. Discrepancies between models are studied both in the linear and in the nonlinear regime of the magnetized Kelvin-Helmholtz instability, to highlight the effects of small scale processes on the nonl...

  20. Observation of Impact Ionization of Shallow States in Sub-Kelvin, High-Purity Germanium

    Science.gov (United States)

    Phipps, A.; Sadoulet, B.; Sundqvist, K. M.

    2016-07-01

    We report on the observation of impact ionization processes involving shallow impurity states in a sub-Kelvin, high-purity n-type germanium detector similar to those used by direct detection dark matter experiments such as the Cryogenic Dark Matter Search. An optical fiber is used to generate packets of charge carriers near one surface of the detector. The charge carriers drift to the opposite surface by application of an electric field. The resulting drift current is measured by a high-speed charge amplifier. The onset of impact ionization for both electron and hole transport is clearly observed in the drift current as the applied electric field is increased above ≈ 5 V/cm. We present the effective charge collection efficiency and trapping length as a function of applied electric field for electrons and holes. We estimate the impact ionization cross section to be on the order of 5× 10^{-13} mathrm {cm}^2.

  1. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  2. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    Science.gov (United States)

    Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  3. Integrated scanning Kelvin probe-scanning electrochemical microscope system: development and first applications.

    Science.gov (United States)

    Maljusch, Artjom; Schönberger, Bernd; Lindner, Armin; Stratmann, Martin; Rohwerder, Michael; Schuhmann, Wolfgang

    2011-08-01

    The integration of a scanning Kelvin probe (SKP) and a scanning electrochemical microscope (SECM) into a single SKP-SECM setup, the concept of the proposed system, its technical realization, and first applications are presented and discussed in detail. A preloaded piezo actuator placed in a grounded stainless steel case was used as the driving mechanism for oscillation of a Pt disk electrode as conventionally used in SECM when the system was operated in the SKP mode. Thus, the same tip is recording the contact potential difference (CPD) during SKP scanning and is used as a working electrode for SECM imaging in the redox-competition mode (RC-SECM). The detection of the local CPD is established by amplification of the displacement current at an ultralow noise operational amplifier and its compensation by application of a variable backing potential (V(b)) in the external circuit. The control of the tip-to-sample distance is performed by applying an additional alternating voltage with a much lower frequency than the oscillation frequency of the Kelvin probe. The main advantage of the SKP-SECM system is that it allows constant distance measurements of the CPD in air under ambient conditions and in the redox-competition mode of the SECM in the electrolyte of choice over the same sample area without replacement of the sample or exchange of the working electrode. The performance of the system was evaluated using a test sample made by sputtering thin Pt and W films on an oxidized silicon wafer. The obtained values of the CPD correlate well with known data, and the electrochemical activity for oxygen reduction is as expected higher over Pt than W. PMID:21675763

  4. Heterologous production of two unusual acyclic carotenoids, 1,1'-dihydroxy-3,4-didehydrolycopene and 1-hydroxy-3,4,3',4'-tetradehydrolycopene by combination of the crtC and crtD genes from Rhodobacter and Rubrivivax.

    Science.gov (United States)

    Steiger, Sabine; Takaichi, Shinichi; Sandmann, Gerhard

    2002-07-17

    Acyclic hydroxy carotenoids were produced from lycopene and 3,4-didehydrolycopene in Escherichia coli by combining different carotenogenic genes including the carotene hydratase gene crtC and the carotene 3,4-desaturase gene crtD. The genes originated either from Rhodobacter species or Rubrivivax gelatinosus. It was shown that the product of crtD from Rubrivivax unlike the one from Rhodobacter is able to convert 1-HO-3,4-didehydrolycopene to 1-HO-3,4,3',4'-tetradehydrolycopene (=3,4,3',4'-tetradehydro-1,2-dihydro-psi,psi-caroten-1-ol). Thus, only when the desaturase from Rubrivivax is expressed can this novel carotenoid be obtained. In the presence of crtC from Rubrivivax, another carotenoid 1,1'-(HO)(2)-3,4-didehydrolycopene (=3,4-didehydrolycopene-1,2,1',2'-tetrahydro-psi,psi-caroten-1,1'-diol) not found in a non-transgenic organism before is formed in E. coli. Its accumulation under these conditions and its absence when crtC from Rubrivivax is replaced by the corresponding gene from Rhodobacter is discussed. The function of the different crtC and crtD genes in the pathway leading to the individual carotenoids is outlined. Since 1,1'-(HO)(2)-3,4-didehydrolycopene could not be produced in substantial amounts and 1-HO-3,4,3',4'-tetradehydrolycopene has not been described before, their structural characteristics were determined for the definite assignment of their identity. This included spectral properties, determination of relative molecular mass as well as the number of hydroxy groups by mass spectroscopy and NMR spectroscopy for 1,1'-(HO)(2)-3,4-didehydrolycopene.

  5. [Monograph for 3-(4-methylbenzylidene)camphor (4-MBC)--HBM values for the sum of metabolites 3-(4-carboxybenzylidene)camphor (3-4CBC) and 3-(4-carboxybenzylidene)-6-hydroxycamphor (3-4 CBHC) in the urine of adults and children. Statement of the HBM Commission of the German Federal Environment Agency].

    Science.gov (United States)

    2016-01-01

    The substance 3-(4-methylbenzylidene)camphor (4-MBC, CAS-No. 36861-47-9 as well as 38102-62-4) is used as UV-filter in cosmetics, mainly in sunscreen lotions. National as well as European evaluations are available for the substance, especially from the Scientific Committee on Consumer Products (SCCP). The SCCP did not derive a TDI-value, but used for a MoS assessment a NOAEL of 25 mg/(kg bw · d) based on effects on the thyroid gland of rats in a subchronic study with oral administration. Newer studies, however, indicate lower NOAEL values, leading to tolerable daily intakes of 0,01 mg/kg bw. The HBM Commission established for the metabolite 3-(4-carboxybenzylidene)camphor (3-4CBC) HBM-I values of 0,09 mg/l urine for adults and 0,06 mg/l urine for children. HBM-I values for the metabolite 3-(4-carboxybenzylidene)-6-hydroxycamphor (3-4CBHC) were set at 0,38 mg/l urine for adults and 0,25 mg/l urine for children. The rounded HBM-I value for the sum of metabolites 3-4CBC und 3-4CBHC is accordingly 0,5 mg/l urine for adults and 0,3 mg/l urine for children. PMID:26721474

  6. Characteristics of pregnant women who use ecstasy (3, 4-methylenedioxymethamphetamine).

    Science.gov (United States)

    Ho, E; Karimi-Tabesh, L; Koren, G

    2001-01-01

    To determine the characteristics of pregnant women who use Ecstasy (3,4-methylenedioxymethamphetamine, MDMA), and to identify reproductive risk factors associated with this group of women. Prospective, observational study. Pregnant women who have contacted the Motherisk Alcohol and Substance Use Helpline at The Hospital for Sick Children, in Toronto, about exposure to drugs, chemicals, infection or radiation. All inquiries from December 1998 to October 2000 concerning pregnant women who reported use of MDMA, and control cases of women not exposed to MDMA selected within the same week of the MDMA callers. Age, maternal demographics, pregnancy characteristics, patterns of alcohol, tobacco, and illicit drug use, psychological/emotional status, sexually transmitted disease, MDMA method and pattern of use, and adverse drug reactions after ingestion of MDMA. The 132 pregnant women who used MDMA were significantly younger (mean 23.2 vs. 31.2 years, Palcohol (66.4% vs. 37.3%, Ppsilocybin were used more frequently among the MDMA sample. Over a third of MDMA users reported psychiatric/emotional problems, including 6.5% with a clinically diagnosed condition that was being treated with medication and/or counseling. Pregnant women who use MDMA tend to be young, single, and report psychological morbidity, and have a clustering of risk factors that may compromise the pregnancy and fetus. Smoking, heavy alcohol intake, and polydrug use, combined with a higher than expected rate of unplanned pregnancies, increases the risk of fetal exposure to potentially harmful substances. It is important to account for the range of confounding risk factors among women who use MDMA in order to define possible direct effects of MDMA in pregnancy.

  7. Biodegradation of 1,2,3,4-tetrachlorodibenzo-p-dioxin in liquid broth by brown-rot fungi.

    Science.gov (United States)

    Perlatti, Bruno; da Silva, Maria Fátima das Graças Fernandes; Fernandes, João Batista; Forim, Moacir Rossi

    2013-11-01

    Dioxins are a class of extremely hazardous molecules that might pose a threat to the environment. This work evaluated the microbial degradation of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD), in liquid broth using three brown-rot fungi and one white-rot fungi as control. A fast and reliable extraction method with recoveries of over 98% together with a validated GC-MS method was developed, and applied to quantify 1,2,3,4-TCDD in liquid broth, mycelia and reaction flask, with detection limits of 10 ppb. Among the four strains tested, brown-rot fungus Aspergillus aculeatus showed best results, removing up to 21% of dioxin after 30-day incubation. The results open both a path for biotechnological interest in bioremediation purposes and environmental behavior studies by using brown-rot fungus.

  8. Subtask 3.4 - Fischer - Tropsch Fuels Development

    Energy Technology Data Exchange (ETDEWEB)

    Strege, Joshua; Snyder, Anthony; Laumb, Jason; Stanislowski, Joshua; Swanson, Michael

    2012-05-01

    Under Subtask 3.4, the Energy & Environmental Research Center (EERC) examined the opportunities and challenges facing FischerTropsch (FT) technology in the United States today. Work was completed in two distinct budget periods (BPs). In BP1, the EERC examined the technical feasibility of using modern warm-gas cleanup techniques for FT synthesis. FT synthesis is typically done using more expensive and complex cold-gas sweetening. Warm-gas cleanup could greatly reduce capital and operating costs, making FT synthesis more attractive for domestic fuel production. Syngas was generated from a variety of coal and biomass types; cleaned of sulfur, moisture, and condensables; and then passed over a pilot-scale FT catalyst bed. Laboratory and modeling work done in support of the pilot-scale effort suggested that the catalyst was performing suboptimally with warm-gas cleanup. Long-term trends showed that the catalyst was also quickly deactivating. In BP3, the EERC compared FT catalyst results using warm-gas cleanup to results using cold-gas sweetening. A gas-sweetening absorption system (GSAS) was designed, modeled, and constructed to sweeten syngas between the gasifier and the pilot-scale FT reactor. Results verified that the catalyst performed much better with gas sweetening than it had with warm-gas cleanup. The catalyst also showed no signs of rapid deactivation when the GSAS was running. Laboratory tests in support of this effort verified that the catalyst had deactivated quickly in BP1 because of exposure to syngas, not because of any design flaw with the pilot-scale FT reactor itself. Based on these results, the EERC concludes that the two biggest issues with using syngas treated with warm-gas cleanup for FT synthesis are high concentrations of CO{sub 2} and volatile organic matter. Other catalysts tested by the EERC may be more tolerant of CO{sub 2}, but volatile matter removal is critical to ensuring long-term FT catalyst operation. This subtask was funded through

  9. A Day For Love

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Young couples drive Valentine’s Day booms in China It is not clear when Chinese couplesstarted celebrating Valentine’s Day,but it has now firmly established itself as an important day around the Spring Festival,

  10. Application of scanning Kelvin probe microscopy for the electrical characterization of microcrystalline silicon for photovoltaics

    International Nuclear Information System (INIS)

    In the last years microcrystalline silicon thin films have attracted great attention as a new photovoltaic material. With this material it is possible to combine simple and cheap low temperature deposition techniques known from amorphous silicon with the long-term stability of the photovoltaic performance like in bulk crystalline silicon solar cells. The critical point is the deposition procedure with numerous tunable parameters influencing the quality and character of the produced diode structures. Additionally there is a great uncertainty about unintentionally incorporated defects, which is not affected by the deposition parameters. Extended investigation of the material, diode and solar cell characteristics is essential in order to correlate the impact of deposition conditions with the quality of the devices. The situation is complicated due to the anisotropic and inhomogeneous character of microcrystalline silicon. Scanning Kelvin probe microscopy (SKPM) is a work function measurement method based on a scanning force microscope (SFM) and a modified Kelvin probe technique. Due to the excellent lateral resolution of the SFM work function measurements with resolutions far below the micrometer level can be carried out. Applied on doped microcrystalline silicon structures it is possible to visualize the position of the Fermi level within the band gap and the influence of the deposition conditions on it. Within this work a SKPM based on a commercially available SFM was constructed and built. Great effort was concentrated on the characterization of the SKPM experiment. On the basis of an extended knowledge about the performance investigations concentrated on cross sections of microcrystalline silicon diode structures produced by hot-wire chemical vapor deposition (HW-CVD). A pin structure for the diodes was chosen due to the low diffusion lengths within this rather defective material. The evolution of the built-in electric drift field within the intrinsic absorber is

  11. Kelvin probe force microscopy of DNA-capped nanoparticles for single-nucleotide polymorphism detection

    Science.gov (United States)

    Lee, Hyungbeen; Lee, Sang Won; Lee, Gyudo; Lee, Wonseok; Lee, Jeong Hoon; Hwang, Kyo Seon; Yang, Jaemoon; Lee, Sang Woo; Yoon, Dae Sung

    2016-07-01

    Kelvin probe force microscopy (KPFM) is a robust toolkit for profiling the surface potential (SP) of biomolecular interactions between DNAs and/or proteins at the single molecule level. However, it has often suffered from background noise and low throughput due to instrumental or environmental constraints, which is regarded as limiting KPFM applications for detection of minute changes in the molecular structures such as single-nucleotide polymorphism (SNP). Here, we show KPFM imaging of DNA-capped nanoparticles (DCNP) that enables SNP detection of the BRCA1 gene owing to sterically well-adjusted DNA-DNA interactions that take place within the confined spaces of DCNP. The average SP values of DCNP interacting with BRCA1 SNP were found to be lower than the DCNP reacting with normal (non-mutant) BRCA1 gene. We also demonstrate that SP characteristics of DCNP with different substrates (e.g., Au, Si, SiO2, and Fe) provide us with a chance to attenuate or augment the SP signal of DCNP without additional enhancement of instrumentation capabilities.Kelvin probe force microscopy (KPFM) is a robust toolkit for profiling the surface potential (SP) of biomolecular interactions between DNAs and/or proteins at the single molecule level. However, it has often suffered from background noise and low throughput due to instrumental or environmental constraints, which is regarded as limiting KPFM applications for detection of minute changes in the molecular structures such as single-nucleotide polymorphism (SNP). Here, we show KPFM imaging of DNA-capped nanoparticles (DCNP) that enables SNP detection of the BRCA1 gene owing to sterically well-adjusted DNA-DNA interactions that take place within the confined spaces of DCNP. The average SP values of DCNP interacting with BRCA1 SNP were found to be lower than the DCNP reacting with normal (non-mutant) BRCA1 gene. We also demonstrate that SP characteristics of DCNP with different substrates (e.g., Au, Si, SiO2, and Fe) provide us with a

  12. Mother’s Day

    Institute of Scientific and Technical Information of China (English)

    张萍

    2009-01-01

    Mother’s Day is a day for each family to honor (尊敬,给……以光荣) its mother ,celebrated (庆祝)on various days in many places around the world.It complements (补足,补充) Father’s Day,the celebration

  13. Noncontact atomic force and Kelvin probe force microscopy on MgO(100) and MgO(100)-supported Ba

    Science.gov (United States)

    Pang, Chi Lun; Sasahara, Akira; Onishi, Hiroshi

    2016-08-01

    Atomically-flat MgO(100) surfaces were prepared by sputtering and annealing. Noncontact atomic force microscopy (NC-AFM) and Kelvin probe force microscopy (KPFM) were used to characterize the MgO(100) surfaces. The NC-AFM images revealed the presence of point defects on an atomically-resolved surface. The surface potential at these point defects, as well as features such as step edges and deposited Ba nanoparticles were mapped using KPFM. The Kelvin images show that the surface potential increases at the point defects and at the step edges. On the other hand, a decrease in the potential was found over Ba nanoparticles which can be explained by electron charge transfer from the Ba to the MgO.

  14. Growth and saturation of the Kelvin-Helmholtz instability with parallel and anti-parallel magnetic fields

    CERN Document Server

    Keppens, R; Westermann, R H J; Goedbloed, J P

    1999-01-01

    We investigate the Kelvin-Helmholtz instability occuring at the interface of a shear flow configuration in 2D compressible magnetohydrodynamics (MHD). The linear growth and the subsequent non-linear saturation of the instability are studied numerically. We consider an initial magnetic field aligned with the shear flow, and analyze the differences between cases where the initial field is unidirectional everywhere (uniform case), and where the field changes sign at the interface (reversed case). We recover and extend known results for pure hydrodynamic and MHD cases with a discussion of the dependence of the non-linear saturation on the wavenumber, the sound Mach number, and the Alfvenic Mach number for the MHD case. A reversed field acts to destabilize the linear phase of the Kelvin-Helmholtz instability compared to the pure hydrodynamic case, while a uniform field suppresses its growth. In resistive MHD, reconnection events almost instantly accelerate the buildup of a global plasma circulation. They play an i...

  15. Wave simulation in biologic media based on the Kelvin-Voigt fractional-derivative stress-strain relation.

    Science.gov (United States)

    Caputo, Michele; Carcione, José M; Cavallini, Fabio

    2011-06-01

    The acoustic behavior of biologic media can be described more realistically using a stress-strain relation based on fractional time derivatives of the strain, since the fractional exponent is an additional fitting parameter. We consider a generalization of the Kelvin-Voigt rheology to the case of rational orders of differentiation, the so-called Kelvin-Voigt fractional-derivative (KVFD) constitutive equation, and introduce a novel modeling method to solve the wave equation by means of the Grünwald-Letnikov approximation and the staggered Fourier pseudospectral method to compute the spatial derivatives. The algorithm can handle complex geometries and general material-property variability. We verify the results by comparison with the analytical solution obtained for wave propagation in homogeneous media. Moreover, we illustrate the use of the algorithm by simulation of wave propagation in normal and cancerous breast tissue. PMID:21601139

  16. The Kelvin-Helmholtz instability under Parker-Spiral Interplanetary Magnetic Field conditions at the magnetospheric flanks

    Science.gov (United States)

    Adamson, E.; Nykyri, K.; Otto, A.

    2016-07-01

    We have generated fully three-dimensional, high-resolution magnetohydrodynamic (MHD) simulations of the Kelvin-Helmholtz (KH) Instability during Parker-Spiral Interplanetary Magnetic Field (IMF) conditions at the dawnside magnetospheric flank magnetopause. Results of these simulations show that, although the draping of a strong tangential magnetic field component around the magnetopause, tailward of the terminator (due to the Parker-Spiral orientation), tends to stabilize the growth of such instabilities within the shear-flow plane, Kelvin-Helmholtz waves with a k -vector tilted out of this plane may, nonetheless, develop into the nonlinear phase. This result suggests that obliquely propagating KH waves may contribute to the dawn-dusk asymmetries observed in plasma sheet parameters.

  17. Light yield of an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin

    CERN Document Server

    Liu, Jing; Soma, Arun Kumar

    2016-01-01

    A light yield of 20.4 $\\pm$ 0.8 photoelectrons/keV was achieved with an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin. This is by far the largest yield in the world achieved with CsI crystals. An energy threshold that is several times lower than the current dark matter experiments utilizing CsI(Tl) crystals may be achievable using this technique. Together with novel CsI crystal purification methods, the technique may be used to improve the sensitivities of dark matter and coherent elastic neutrino-nucleus scattering experiments. Also measured were the scintillation light decay constants of the undoped CsI crystal at both room temperature and 77 Kelvin. The results are consistent with those in the literature.

  18. AAS 227: Day 4

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    mean its not typical. While we wait for more and better observations of exoplanet systems, theory can help us understand why the Solar System formed the way it did, and where to look for systems that formed the same way. For example, some of Murray-Clays previous work has shown that metal-rich stars tend to host more hot Jupiters and eccentric giant planets (very different from Solar System architecture). So if we want to find more systems like our own, we need to search around stars with low-to-moderate metallicity.Extrasolar Planets: Hosts, Interactions, Formation, and Interiors (by Caroline Morley)This session was a mashup of a variety of planetary topics ranging from solar flares to interiors to habitability.Leslie Rogers kicked off the session by presenting work done in collaboration with her student Ellen Price to constrain the composition of the ultra-short period (4 hours!?!) planet candidate KOI 1843.03 using models of the objects interior. Since its so close to the star, it can only exist without being torn apart if its very dense, which allows them to calculate that it must be iron-rich like Mercury!Next Kevin Thielen, an undergrad at Eckerd College, presented results from a summer project to apply a variable polytrope index to planet models. Tom Barclay then showed models that demonstrate the huge effect that having giant planets in the outer solar system has on the formation of terrestrial planets. He finds that without Jupiter and Saturn, more planets would form (8 instead of 3-4!) and giant impacts (like the moon-forming impact) would be more frequent but less energetic.Aomawa Shields shifted to discuss her 3D GCM models to determine the orbital configurations that would lead to liquid water on the surface of the planet Kepler-62f. She determines the effect of eccentricity, axis tilt (obliquity), and rotation rate on habitability. Edward Guinan brought us closer to home discussing the potential for superflares solar flares up to hundreds of times more

  19. Kelvin probe force microscopy of metallic surfaces used in Casimir force measurements

    Science.gov (United States)

    Behunin, R. O.; Dalvit, D. A. R.; Decca, R. S.; Genet, C.; Jung, I. W.; Lambrecht, A.; Liscio, A.; López, D.; Reynaud, S.; Schnoering, G.; Voisin, G.; Zeng, Y.

    2014-12-01

    Kelvin probe force microscopy at normal pressure was performed by two different groups on the same Au-coated planar sample used to measure the Casimir interaction in a sphere-plane geometry. The obtained voltage distribution was used to calculate the separation dependence of the electrostatic pressure Pres(D ) in the configuration of the Casimir experiments. In the calculation it was assumed that the potential distribution in the sphere has the same statistical properties as the measured one, and that there are no correlation effects on the potential distributions due to the presence of the other surface. The result of this calculation, using the currently available knowledge, is that Pres(D ) does not explain the magnitude or the separation dependence of the difference Δ P (D ) between the measured Casimir pressure and the one calculated using a Drude model for the electromagnetic response of Au. We discuss in the conclusions the points which have to be checked out by future work, including the influence of pressure and a more accurate determination of the patch distribution, in order to confirm these results.

  20. Quantitative dopant profiling in semiconductors. A new approach to Kelvin probe force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Baumgart, Christine

    2012-07-01

    Failure analysis and optimization of semiconducting devices request knowledge of their electrical properties. To meet the demands of today's semiconductor industry, an electrical nanometrology technique is required which provides quantitative information about the doping profile and which enables scans with a lateral resolution in the sub-10 nm range. In the presented work it is shown that Kelvin probe force microscopy (KPFM) is a very promising electrical nanometrology technique to face this challenge. The technical and physical aspects of KPFM measurements on semiconductors required for the correct interpretation of the detected KPFM bias are discussed. A new KPFM model is developed which enables the quantitative correlation between the probed KPFM bias and the dopant concentration in the investigated semiconducting sample. Quantitative dopant profiling by means of the new KPFM model is demonstrated by the example of differently structured, n- and p-type doped silicon. Additionally, the transport of charge carriers during KPFM measurements, in particular in the presence of intrinsic electric fields due to vertical and horizontal pn junctions as well as due to surface space charge regions, is discussed. Detailed investigations show that transport of charge carriers in the semiconducting sample is a crucial aspect and has to be taken into account when aiming for a quantitative evaluation of the probed KPFM bias.

  1. Instability of Supersonic Cold Streams Feeding Galaxies I: Linear Kelvin-Helmholtz Instability with Body Modes

    CERN Document Server

    Mandelker, Nir; Dekel, Avishai; Birnboim, Yuval; Burkert, Andreas; Krumholz, Mark R; Steinberg, Elad

    2016-01-01

    Massive galaxies at high redshift are predicted to be fed from the cosmic web by narrow, dense, cold streams. These streams penetrate supersonically through the hot medium encompassed by a stable shock near the virial radius of the dark-matter halo. Our long-term goal is to explore the heating and dissipation rate of the streams and their fragmentation and possible breakup, in order to understand how galaxies are fed, and how this affects their star-formation rate and morphology. We present here the first step, where we analyze the linear Kelvin-Helmholtz instability (KHI) of a cold, dense slab or cylinder flowing through a hot, dilute medium in the transonic regime. The current analysis is limited to the adiabatic case with no gravity and assuming equal pressure in the stream and the medium. By analytically solving the linear dispersion relation, we find a transition from a dominance of the familiar rapidly growing surface modes in the subsonic regime to more slowly growing body modes in the supersonic regim...

  2. Study on the sputter-cleaning processes of Ni by means of Kelvin probe

    Science.gov (United States)

    Luo, G.-N.; Yamaguchi, K.; Terai, T.; Yamawaki, M.

    2002-05-01

    A new device has been established to study the surface properties of materials under low energy ion irradiation by means of a Kelvin probe. The serious impact of space charging on the probe was observed, and verified unambiguously via a simulation test. The appropriate measures applied to the system function quite well, and suppress the detrimental influence effectively. The preliminary experiment of helium ion irradiation on nickel resulted in a decrease in work function (WF) at the low fluence, followed by an increase with increasing the fluence till the final saturation was achieved. The behavior can be explained using a two-layer surface model, i.e., the desorption of the topmost loosely bound adsorbed layer due to the irradiation decreases the surface dipole moment towards the bulk, in turn the WF decreases; then the native oxide layer on the bulk is sputtered away gradually, which induces the increase in the WF; finally, the saturation is reached as a result of the balance between the sputtering and the adsorption of the species from the residual gases. The desorption/adsorption experiment further verified the validity of the model.

  3. Evaluating gyro-viscosity in the Kelvin-Helmholtz instability by kinetic simulations

    Science.gov (United States)

    Umeda, Takayuki; Yamauchi, Natsuki; Wada, Yasutaka; Ueno, Satoshi

    2016-05-01

    In the present paper, the finite-Larmor-radius (gyro-viscous) term [K. V. Roberts and J. B. Taylor, Phys. Rev. Lett. 8, 197-198 (1962)] is evaluated by using a full kinetic Vlasov simulation result of the Kelvin-Helmholtz instability (KHI). The velocity field and the pressure tensor are calculated from the high-resolution data of the velocity distribution functions obtained by the Vlasov simulation, which are used to approximate the Finite-Larmor-Radius (FLR) term according to Roberts and Taylor [Phys. Rev. Lett. 8, 197-198 (1962)]. The direct comparison between the pressure tensor and the FLR term shows an agreement. It is also shown that the anisotropic pressure gradient enhanced the linear growth of the KHI when the inner product between the vorticity of the primary velocity shear layer and the magnetic field is negative, which is consistent with the previous FLR-magnetohydrodynamic simulation result. This result suggests that it is not sufficient for reproducing the kinetic simulation result by fluid simulations to include the FLR term (or the pressure tensor) only in the equation of motion for fluid.

  4. Full data acquisition in Kelvin Probe Force Microscopy: Mapping dynamic electric phenomena in real space

    Science.gov (United States)

    Collins, Liam; Belianinov, Alex; Somnath, Suhas; Balke, Nina; Kalinin, Sergei V.; Jesse, Stephen

    2016-08-01

    Kelvin probe force microscopy (KPFM) has provided deep insights into the local electronic, ionic and electrochemical functionalities in a broad range of materials and devices. In classical KPFM, which utilizes heterodyne detection and closed loop bias feedback, the cantilever response is down-sampled to a single measurement of the contact potential difference (CPD) per pixel. This level of detail, however, is insufficient for materials and devices involving bias and time dependent electrochemical events; or at solid-liquid interfaces, where non-linear or lossy dielectrics are present. Here, we demonstrate direct recovery of the bias dependence of the electrostatic force at high temporal resolution using General acquisition Mode (G-Mode) KPFM. G-Mode KPFM utilizes high speed detection, compression, and storage of the raw cantilever deflection signal in its entirety at high sampling rates. We show how G-Mode KPFM can be used to capture nanoscale CPD and capacitance information with a temporal resolution much faster than the cantilever bandwidth, determined by the modulation frequency of the AC voltage. In this way, G-Mode KPFM offers a new paradigm to study dynamic electric phenomena in electroactive interfaces as well as a promising route to extend KPFM to the solid-liquid interface.

  5. Kelvin probe force microscopy for characterizing doped semiconductors for future sensor applications in nano- and biotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Heidemarie, E-mail: Heidemarie.Schmidt@etit.tu-chemnitz.de [Chemnitz University of Technology, Department of Materials for Nanoelectronics, Faculty of Electrical Engineering and Information Technology, 09126 Chemnitz (Germany); Habicht, Stefan; Feste, Sebastian [Forschungszentrum Jülich, Peter Grünberg Institute 9 (PGI-9-IT), 52425 Jülich (Germany); JARA-FIT, Fundamentals of Future Information Technology (Germany); Müller, Anne-Dorothea [Anfatec Instruments AG, Melanchthonstr. 28, 08606 Oelsnitz (Germany); Schmidt, Oliver G. [Chemnitz University of Technology, Department of Materials for Nanoelectronics, Faculty of Electrical Engineering and Information Technology, 09126 Chemnitz (Germany); Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstraße 20, 01069 Dresden (Germany)

    2013-09-15

    Kelvin probe force microscopy (KPFM) is one of the most promising non-contact electrical nanometrology techniques to characterize doped semiconductors. By applying a recently introduced explanation of measured KPFM signals, we show the applicability of KPFM to determine and control surface-near electrostatic forces in planar doped silicon and in doped silicon nanostructures. Surface-near electrostatic forces may be used for the immobilization of nano- and biomaterials in future sensor applications in nano- and biotechnology. Additionally, the influence of the electrostatic potential distribution in doped semiconductor nanostructures, e.g. in horizontal Si nanowires, and its influence on the surface-near electrostatic forces are discussed. It is explained how drift and diffusion of injected electrons and holes in intrinsic electric fields influence the detected KPFM signal. For example KPFM is successfully employed to locate p{sup +}p and n{sup +}p junctions along B-doped and As-doped p-Si nanowires, respectively. As an outlook the physical immobilization and the transport of biomaterials above arrays of separately addressable doped semiconductor cells will be discussed.

  6. Kelvin probe force microscopy for characterizing doped semiconductors for future sensor applications in nano- and biotechnology

    Science.gov (United States)

    Schmidt, Heidemarie; Habicht, Stefan; Feste, Sebastian; Müller, Anne-Dorothea; Schmidt, Oliver G.

    2013-09-01

    Kelvin probe force microscopy (KPFM) is one of the most promising non-contact electrical nanometrology techniques to characterize doped semiconductors. By applying a recently introduced explanation of measured KPFM signals, we show the applicability of KPFM to determine and control surface-near electrostatic forces in planar doped silicon and in doped silicon nanostructures. Surface-near electrostatic forces may be used for the immobilization of nano- and biomaterials in future sensor applications in nano- and biotechnology. Additionally, the influence of the electrostatic potential distribution in doped semiconductor nanostructures, e.g. in horizontal Si nanowires, and its influence on the surface-near electrostatic forces are discussed. It is explained how drift and diffusion of injected electrons and holes in intrinsic electric fields influence the detected KPFM signal. For example KPFM is successfully employed to locate p+p and n+p junctions along B-doped and As-doped p-Si nanowires, respectively. As an outlook the physical immobilization and the transport of biomaterials above arrays of separately addressable doped semiconductor cells will be discussed.

  7. Kelvin probe characterization of buried graphitic microchannels in single-crystal diamond

    Science.gov (United States)

    Bernardi, E.; Battiato, A.; Olivero, P.; Picollo, F.; Vittone, E.

    2015-01-01

    In this work, we present an investigation by Kelvin Probe Microscopy (KPM) of buried graphitic microchannels fabricated in single-crystal diamond by direct MeV ion microbeam writing. Metal deposition of variable-thickness masks was adopted to implant channels with emerging endpoints and high temperature annealing was performed in order to induce the graphitization of the highly-damaged buried region. When an electrical current was flowing through the biased buried channel, the structure was clearly evidenced by KPM maps of the electrical potential of the surface region overlying the channel at increasing distances from the grounded electrode. The KPM profiling shows regions of opposite contrast located at different distances from the endpoints of the channel. This effect is attributed to the different electrical conduction properties of the surface and of the buried graphitic layer. The model adopted to interpret these KPM maps and profiles proved to be suitable for the electronic characterization of buried conductive channels, providing a non-invasive method to measure the local resistivity with a micrometer resolution. The results demonstrate the potential of the technique as a powerful diagnostic tool to monitor the functionality of all-carbon graphite/diamond devices to be fabricated by MeV ion beam lithography.

  8. Multifrequency spectrum analysis using fully digital G Mode-Kelvin probe force microscopy

    Science.gov (United States)

    Collins, Liam; Belianinov, Alex; Somnath, Suhas; Rodriguez, Brian J.; Balke, Nina; Kalinin, Sergei V.; Jesse, Stephen

    2016-03-01

    Since its inception over two decades ago, Kelvin probe force microscopy (KPFM) has become the standard technique for characterizing electrostatic, electrochemical and electronic properties at the nanoscale. In this work, we present a purely digital, software-based approach to KPFM utilizing big data acquisition and analysis methods. General mode (G-Mode) KPFM works by capturing the entire photodetector data stream, typically at the sampling rate limit, followed by subsequent de-noising, analysis and compression of the cantilever response. We demonstrate that the G-Mode approach allows simultaneous multi-harmonic detection, combined with on-the-fly transfer function correction—required for quantitative CPD mapping. The KPFM approach outlined in this work significantly simplifies the technique by avoiding cumbersome instrumentation optimization steps (i.e. lock in parameters, feedback gains etc), while also retaining the flexibility to be implemented on any atomic force microscopy platform. We demonstrate the added advantages of G-Mode KPFM by allowing simultaneous mapping of CPD and capacitance gradient (C‧) channels as well as increased flexibility in data exploration across frequency, time, space, and noise domains. G-Mode KPFM is particularly suitable for characterizing voltage sensitive materials or for operation in conductive electrolytes, and will be useful for probing electrodynamics in photovoltaics, liquids and ionic conductors.

  9. Scanning Kelvin probe measurements on As-doped CdTe solar cells

    International Nuclear Information System (INIS)

    Scanning Kelvin probe microscopy (SKPM) has been used to study the Fermi level shift in arsenic (As) doped cadmium telluride (CdTe) photovoltaic devices. The contact potential difference (CPD) between probe tip and sample surface revealed that increasing As concentrations in CdTe led to a decrease in CPD. This highlighted a downward shift in the CdTe Fermi level and an increase in the CdTe work function. Using a highly oriented pyrolytic graphite sample in ambient conditions as a reference, the absolute work functions of the CdTe samples were estimated to vary from 3.88 to 4.09 eV. High-resolution SKPM measurements revealed localized shifts in CPD at CdTe grain boundaries. This was directly correlated to As doping concentrations, and indicated the segregation of As to grain boundaries. A mechanism is proposed where localized band bending at grain boundaries channels minority carriers away from the grain boundary, leading to reduced carrier recombination. (paper)

  10. Striations in the Taurus molecular cloud: Kelvin-Helmholtz instability or MHD waves?

    CERN Document Server

    Heyer, M; Yildiz, U A; Snell, R L; Falgarone, E; Pineda, J

    2016-01-01

    The origin of striations aligned along the local magnetic field direction in the translucent envelope of the Taurus molecular cloud is examined with new observations of 12CO and 13CO J=2-1 emission obtained with the 10~m submillimeter telescope of the Arizona Radio Observatory. These data identify a periodic pattern of excess blue and redshifted emission that is responsible for the striations. For both 12CO and 13CO, spatial variations of the J=2-1 to J=1-0 line ratio are small and are not spatially correlated with the striation locations. A medium comprised of unresolved CO emitting substructures (cells) with a beam area filling factor less than unity at any velocity is required to explain the average line ratios and brightness temperatures. We propose that the striations result from the modulation of velocities and the beam filling factor of the cells as a result of either the Kelvin-Helmholtz instability or magnetosonic waves propagating through the envelope of the Taurus molecular cloud. Both processes ar...

  11. Kelvin probe force microscopy for local characterisation of active nanoelectronic devices

    Directory of Open Access Journals (Sweden)

    Tino Wagner

    2015-11-01

    Full Text Available Frequency modulated Kelvin probe force microscopy (FM-KFM is the method of choice for high resolution measurements of local surface potentials, yet on coarse topographic structures most researchers revert to amplitude modulated lift-mode techniques for better stability. This approach inevitably translates into lower lateral resolution and pronounced capacitive averaging of the locally measured contact potential difference. Furthermore, local changes in the strength of the electrostatic interaction between tip and surface easily lead to topography crosstalk seen in the surface potential. To take full advantage of the superior resolution of FM-KFM while maintaining robust topography feedback and minimal crosstalk, we introduce a novel FM-KFM controller based on a Kalman filter and direct demodulation of sidebands. We discuss the origin of sidebands in FM-KFM irrespective of the cantilever quality factor and how direct sideband demodulation enables robust amplitude modulated topography feedback. Finally, we demonstrate our single-scan FM-KFM technique on an active nanoelectronic device consisting of a 70 nm diameter InAs nanowire contacted by a pair of 120 nm thick electrodes.

  12. Kelvin probe force microscopy for local characterisation of active nanoelectronic devices.

    Science.gov (United States)

    Wagner, Tino; Beyer, Hannes; Reissner, Patrick; Mensch, Philipp; Riel, Heike; Gotsmann, Bernd; Stemmer, Andreas

    2015-01-01

    Frequency modulated Kelvin probe force microscopy (FM-KFM) is the method of choice for high resolution measurements of local surface potentials, yet on coarse topographic structures most researchers revert to amplitude modulated lift-mode techniques for better stability. This approach inevitably translates into lower lateral resolution and pronounced capacitive averaging of the locally measured contact potential difference. Furthermore, local changes in the strength of the electrostatic interaction between tip and surface easily lead to topography crosstalk seen in the surface potential. To take full advantage of the superior resolution of FM-KFM while maintaining robust topography feedback and minimal crosstalk, we introduce a novel FM-KFM controller based on a Kalman filter and direct demodulation of sidebands. We discuss the origin of sidebands in FM-KFM irrespective of the cantilever quality factor and how direct sideband demodulation enables robust amplitude modulated topography feedback. Finally, we demonstrate our single-scan FM-KFM technique on an active nanoelectronic device consisting of a 70 nm diameter InAs nanowire contacted by a pair of 120 nm thick electrodes. PMID:26734511

  13. The effect of Prandtl number on mixing in low Reynolds number Kelvin-Helmholtz billows

    Science.gov (United States)

    Rahmani, M.; Seymour, B. R.; Lawrence, G. A.

    2016-05-01

    The effect of Prandtl number on mixing in temporally evolving Kelvin-Helmholtz (KH) instabilities at low to moderate Reynolds numbers is studied through direct numerical simulation. We distinguish between the mixing induced by the primary billow and the mixing generated by three-dimensional motions by performing each simulation in two and three dimensions. The results indicate that the time evolution of the rate of two- and three-dimensional mixing through different stages of the life cycle of KH flow is significantly influenced by the Prandtl number. As the Prandtl number increases, the final amount of mixing increases for Reynolds that are too low to support active three-dimensional motions. This trend is the opposite in sufficiently high Reynolds number KH flows that can overcome viscous effects and develop significant three-dimensional instabilities. While the mixing generated in the two-dimensional flows, uniform in the span-wise direction, is not significantly dependent on the Prandtl number, the turbulent mixing induced by three-dimensional motions is a function of the Prandtl number. We observe a steady increase in the total amount of mixing for buoyancy Reynolds numbers above 7, consistent with the results of Shih et al. ["Parameterization of turbulent fluxes and scales using homogeneous sheared stably stratified turbulence simulations," J. Fluid Mech. 525, 193-214 (2005)]. Both maximum instantaneous and cumulative mixing efficiencies exhibit a decreasing trend with increasing Prandtl number. We compare the dependence of the mixing efficiency on Prandtl number to previous studies.

  14. The effect of Prandtl number on mixing in low Reynolds number Kelvin-Helmholtz billows

    CERN Document Server

    Rahmani, Mona; Seymour, Brian

    2014-01-01

    The effect of Prandtl number on the evolution of Kelvin-Helmholtz (KH) billows and the amount of mixing they generate is studied through direct numerical simulation (DNS). The results indicate that the time evolution of the rate of mixing through different stages of the life-cycle of KH flow is significantly influenced by the Prandtl number. As the Prandtl number increases, the final amount of mixing increases for Reynolds that are too low to support active three-dimensional motions. This trend is the opposite in sufficiently high Reynolds number KH flows that can overcome viscous effects, and develop significant three-dimensional instabilities. While the mixing generated in the two-dimensional flows, uniform in the span-wise direction, is not significantly dependent on the Prandtl number, the turbulent mixing induced by three-dimensional motions is a function of the Prandtl number. The turbulent mixing efficiency near the end of the turbulence decay phase approaches 0.2, the commonly observed value in the oc...

  15. A Numerical Method of the Euler-Bernoulli Beam with Optimal Local Kelvin-Voigt Damping

    Directory of Open Access Journals (Sweden)

    Xin Yu

    2014-01-01

    Full Text Available This paper deals with the numerical approximation problem of the optimal control problem governed by the Euler-Bernoulli beam equation with local Kelvin-Voigt damping, which is a nonlinear coefficient control problem with control constraints. The goal of this problem is to design a control input numerically, which is the damping and distributes locally on a subinterval of the region occupied by the beam, such that the total energy of the beam and the control on a given time period is minimal. We firstly use the finite element method (FEM to obtain a finite-dimensional model based on the original PDE system. Then, using the control parameterization method, we approximate the finite-dimensional problem by a standard optimal parameter selection problem, which is a suboptimal problem and can be solved numerically by nonlinear mathematical programming algorithm. At last, some simulation studies will be presented by the proposed numerical approximation method in this paper, where the damping controls act on different locations of the Euler-Bernoulli beam.

  16. Homogenization of a thermo-chemo-viscoelastic Kelvin-Voigt model

    Science.gov (United States)

    Amosov, Andrey; Kostin, Ilya; Panasenko, Grigory; Smyshlyaev, Valery P.

    2013-08-01

    The paper is devoted to a model for the procedure of formation of a composite material constituted of solid fibers and of a solidifying matrix. The solidification process for the matrix depends on the temperature and on the degree of cure, which are used for the modeling of the mechanical properties of the matrix. Namely, the mechanical properties are described by Kelvin-Voigt viscoelastic equation with rapidly oscillating periodic coefficients depending on the temperature and the degree of cure. The latter are in turn solutions of a thermo-chemical problem with rapidly varying coefficients. We prove an error estimate for approximation of the viscoelastic problem by the same equation but with the coefficients depending on solution to the homogenized thermo-chemical problem. This estimate, in combination with our recent estimates for the viscoelastic (with time-dependent coefficients) and thermo-chemical homogenization problems, generates the overall error bound for the asymptotic solution to the full coupled thermo-chemo-viscoelastic model.

  17. Electron Debye scale Kelvin-Helmholtz instability: Electrostatic particle-in-cell simulations

    Science.gov (United States)

    Lee, Sang-Yun; Lee, Ensang; Kim, Khan-Hyuk; Lee, Dong-Hun; Seon, Jongho; Jin, Ho

    2015-12-01

    In this paper, we investigated the electron Debye scale Kelvin-Helmholtz (KH) instability using two-dimensional electrostatic particle-in-cell simulations. We introduced a velocity shear layer with a thickness comparable to the electron Debye length and examined the generation of the KH instability. The KH instability occurs in a similar manner as observed in the KH instabilities in fluid or ion scales producing surface waves and rolled-up vortices. The strength and growth rate of the electron Debye scale KH instability is affected by the structure of the velocity shear layer. The strength depends on the magnitude of the velocity and the growth rate on the velocity gradient of the shear layer. However, the development of the electron Debye scale KH instability is mainly determined by the electric field generated by charge separation. Significant mixing of electrons occurs across the shear layer, and a fraction of electrons can penetrate deeply into the opposite side fairly far from the vortices across the shear layer.

  18. Electrostatic Kelvin-Helmholtz instability in a radially injected plasma cloud

    Science.gov (United States)

    Sydora, R. D.; Wagner, J. S.; Lee, L. C.; Wescott, E. M.; Tajima, T.

    1983-01-01

    An elecrostatic finite-sized particle simulation model is used to study the early time-scale phenomena asociated with an impulsively injected plasma, expanding radially, normal to a strong ambient magnetic field. Results of the simulation show the early formation of a radial polarization electric field due to ion-electron charge separation which causes electrons to drift in the azimuthal direction. Velocity shear within this motion gives rise to a Kelvin-Helmholtz (dioxotron) instability, creating a radial fluted pattern as the plasma expands. In the nonlinear stage of instability, azimuthal variations in the electric field are observed which cause electrons to drift across the magnetic field, thereby reducing the space charge created by energetic ion expansion. The results of a linear stability analysis reveal that for a decreasing amount of charge separation in the plasma, the number of unstable azimuthal modes at maximum growth rate increases. Also, as the thickness of the electron ring increases, a fewer number of unstable modes develops for a given amount of charge separation. It is concluded that electrons become unstable at the very early time scale, within an ion gyroperiod, and that unstable electrons lead to modification of the ion dynamics.

  19. Kelvin--Helmholtz instability of magnetohydrodynamic waves propagating on solar surges

    CERN Document Server

    Zhelyazkov, I; Srivastava, A K; Mishonov, T

    2014-01-01

    In the present paper, we study the evolutionary conditions for Kelvin--Helmholtz (KH) instability in a high-temperature solar surge observed in NOAA AR11271 using the Solar Dynamics Observatory data on 2011 August 25. We study the propagation of normal MHD modes in a flux tube considering the two cases, notably of untwisted magnetic flux tube and the twisted one. The numerical solution to the dispersion relation shows that the kink ($m = 1$) wave traveling in an untwisted flux tube becomes unstable if the jet speed exceeds $1060$ km\\,s$^{-1}$ -- a speed which is inaccessible for solar surges. A weak twist (the ratio of azimuthal to longitudinal magnetic field component) of the internal magnetic field in the range of $0.025$--$0.2$ does not change substantially the critical flow velocity. Thus, one implies that, in general, the kink mode is stable against the KH instability. It turns out, however, that the $m = -2$ and $m = -3$ MHD modes can become unstable when the twist parameter has values between $0.2$ and...

  20. Mechanical stability of a microscope setup working at a few kelvins for single-molecule localization

    Energy Technology Data Exchange (ETDEWEB)

    Hinohara, Takuya; Hamada, Yuki I.; Nakamura, Ippei; Matsushita, Michio, E-mail: matsushita@phys.titech.ac.jp; Fujiyoshi, Satoru

    2013-06-20

    Highlights: ► Localization precision of the image of a point source is free from diffraction. ► Prerequisite for the precision is stability of the sample and objective at 1.5 K. ► We developed a rigid imaging unit to make image of scattering of a sample bead. ► The centroid of the scattering image of a bead was determined for 800 images. ► The standard deviation of the 800 centroids measured in 17 min was 0.85 nm. - Abstract: A great advantage of single-molecule fluorescence imaging is the localization precision of molecule beyond the diffraction limit. Although longer signal-acquisition yields higher precision, acquisition time at room temperature is normally limited by photobleaching, thermal diffusion, and so on. At low temperature of a few kelvins, much longer acquisition is possible and will improve precision if the sample and the objective are held stably enough. The present work examined holding stability of the sample and objective at 1.5 K in superfluid helium in the helium bath. The stability was evaluated by localization precision of a point scattering source of a polymer bead. Scattered light was collected by the objective, and imaged by a home-built rigid imaging unit. The standard deviation of the centroid position determined for 800 images taken continuously in 17 min was 0.5 nm in the horizontal and 0.9 nm in the vertical directions.

  1. Screening properties of graphene layers studied by Kelvin Probe Force Microscopy and Landau Level Spectroscopy

    Science.gov (United States)

    Vetick, John; Lu, Chih-Pin; Altvater, Michael; Duan, Junxi; Li, Guohong; Andrei, Eva Y.

    2015-03-01

    Graphene is one of the best conductors known, but due to its two dimensional structure and the need to support it on insulating substrates, its electronic properties are often masked by substrate-induced random potential fluctuations. In order to realize graphene's full potential for electronic application it is therefore important to understand its screening properties and to find ways to minimize substrate invasiveness. We employed Kelvin Probe Force microscopy (KPFM) to investigate the screening properties of CVD grown graphene crystals as a function of layer number and substrate material using a gated device geometry. The KPFM study was complemented by low temperature scanning tunneling microscopy and Landau level spectroscopy in similar samples and device configurations. Measurements were carried out on single layer, bilayer, trilayer and twisted bilayer samples deposited on SiO2 and hBN substrates. Our findings show that twisted graphene layers provide superior screening of charged impurities and random potentials while at the same time preserving the unique electronic band structure of single layer graphene. Work Supported by DOE-FG02-99ER45742 and NSF DMR 1207108.

  2. Global reconnection topology as inferred from plasma observations inside Kelvin-Helmholtz vortices

    Directory of Open Access Journals (Sweden)

    M. B. Bavassano Cattaneo

    2010-04-01

    Full Text Available During a long lasting period of northward interplanetary magnetic field and high solar wind speed (above 700 km/s, the Cluster spacecraft go across a number of very large rolled-up Kelvin-Helmholtz (KH vortices at the dusk magnetopause, close to the terminator. The peculiarity of the present event is a particular sequence of ions and electrons distribution functions observed repeatedly inside each vortex. In particular, whenever Cluster crosses the current layer inside the vortices, multiple field-aligned ion populations appear, suggesting the occurrence of reconnection. In addition, the ion data display a clear velocity filter effect both at the leading and at the trailing edge of each vortex. This effect is not present in the simultaneous electron data. Unlike other KH studies reported in the literature in which reconnection occurs within the vortices, in the present event the observations are not compatible with local reconnection, but are accounted for by lobe reconnection occurring along an extended X-line at the terminator in the Southern Hemisphere. The reconnected field lines "sink" across the magnetopause and then convect tailward-duskward where they become embedded in the vortices. Another observational evidence is the detected presence of solar wind plasma on the magnetospheric side of the vortices, which confirms unambiguously the occurrence of mass transport across the magnetopause already reported in the literature. The proposed reconnection scenario accounts for all the observational aspects, regarding both the transport process and the kinetic signatures.

  3. Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors

    Science.gov (United States)

    Kehayias, Christopher E.; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

    2013-06-01

    Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

  4. Full data acquisition in Kelvin Probe Force Microscopy: Mapping dynamic electric phenomena in real space.

    Science.gov (United States)

    Collins, Liam; Belianinov, Alex; Somnath, Suhas; Balke, Nina; Kalinin, Sergei V; Jesse, Stephen

    2016-01-01

    Kelvin probe force microscopy (KPFM) has provided deep insights into the local electronic, ionic and electrochemical functionalities in a broad range of materials and devices. In classical KPFM, which utilizes heterodyne detection and closed loop bias feedback, the cantilever response is down-sampled to a single measurement of the contact potential difference (CPD) per pixel. This level of detail, however, is insufficient for materials and devices involving bias and time dependent electrochemical events; or at solid-liquid interfaces, where non-linear or lossy dielectrics are present. Here, we demonstrate direct recovery of the bias dependence of the electrostatic force at high temporal resolution using General acquisition Mode (G-Mode) KPFM. G-Mode KPFM utilizes high speed detection, compression, and storage of the raw cantilever deflection signal in its entirety at high sampling rates. We show how G-Mode KPFM can be used to capture nanoscale CPD and capacitance information with a temporal resolution much faster than the cantilever bandwidth, determined by the modulation frequency of the AC voltage. In this way, G-Mode KPFM offers a new paradigm to study dynamic electric phenomena in electroactive interfaces as well as a promising route to extend KPFM to the solid-liquid interface. PMID:27514987

  5. SDO/AIA Observation of Kelvin-Helmholtz Instability in the Solar Corona

    Science.gov (United States)

    Ofman, L.; Thompson, B. J.

    2011-01-01

    We present observations of the formation, propagation and decay of vortex-shaped features in coronal images from the Solar Dynamics Observatory (SDO) associated with an eruption starting at about 2:30UT on Apr 8, 2010. The series of vortices formed along the interface between an erupting (dimming) region and the surrounding corona. They ranged in size from several to ten arcseconds, and traveled along the interface at 6-14 km s-1. The features were clearly visible in six out of the seven different EUV wavebands of the Atmospheric Imaging Assembly (AIA). Based on the structure, formation, propagation and decay of these features, we identified these features as the first observations of the Kelvin- Helmholtz (KH) instability in the corona in EUV. The interpretation is supported by linear analysis and by MHD model of KH instability. We conclude that the instability is driven by the velocity shear between the erupting and closed magnetic field of the Coronal Mass Ejection (CME).

  6. The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

    Directory of Open Access Journals (Sweden)

    A. N. Onohara

    2013-02-01

    Full Text Available The main purpose of this study is to investigate the vertical coupling between the mesosphere and lower thermosphere (MLT region and the ionosphere through ultra-fast Kelvin (UFK waves in the equatorial atmosphere. The effect of UFK waves on the ionospheric parameters was estimated using an ionospheric model which calculates electrostatic potential in the E-region and solves coupled electrodynamics of the equatorial ionosphere in the E- and F-regions. The UFK wave was observed in the South American equatorial region during February–March 2005. The MLT wind data obtained by meteor radar at São João do Cariri (7.5° S, 37.5° W and ionospheric F-layer bottom height (h'F observed by ionosonde at Fortaleza (3.9° S; 38.4° W were used in order to calculate the wave characteristics and amplitude of oscillation. The simulation results showed that the combined electrodynamical effect of tides and UFK waves in the MLT region could explain the oscillations observed in the ionospheric parameters.

  7. Kelvin-Helmholtz instability with mass transfer through porous media:Effect of irrotational viscous pressure

    Institute of Scientific and Technical Information of China (English)

    AWASTHI Mukesh Kumar

    2014-01-01

    This paper studies the effect of the irrotational viscous pressure on Kelvin-Helmholtz instability of the plane interface of two viscous and incompressible fluids in a fully saturated porous media with mass and heat transfers across the interface. In the earlier work, the instability of the plane interface of two viscous and streaming miscible fluids through porous media was studied by assuming that the motion and the pressure are irrotational and the viscosity enters the normal stress balance. This theory is called the viscous potential flow theory. Here, we use another irrotational theory in which the discontinuities in the irrotational tangential velocity and shear stress are eliminated in the global energy balance by considering viscous contributions of the irrotational pressure. The Darcy-Brinkman model is used in the investigation and the stability criterion is formulated in terms of a critical value of the relative velocity. It is observed that the heat and mass transfer has a destabilizing effect on the stability of the system while the irrotational shearing stresses stabilize the system.

  8. What is the angle of a nonlinear Kelvin ship wave pattern?

    CERN Document Server

    Pethiyagoda, Ravindra; Moroney, Timothy J

    2014-01-01

    While the half-angle which encloses a Kelvin ship wave pattern is commonly accepted to be 19.47 degrees, recent observations and calculations for sufficiently fast-moving ships suggest that the apparent wake angle decreases with ship speed. One explanation for this decrease in angle relies on the assumption that a ship cannot generate wavelengths much greater than its hull length. An alternative interpretation is that the wave pattern that is observed in practice is defined by the location of the highest peaks; for wakes created by sufficiently fast-moving objects, these highest peaks no longer lie on the outermost divergent waves, resulting in a smaller apparent angle. In this paper, we focus on the problem of free surface flow past a submerged point source. In the linear case, we measure the apparent wake angle formed by the highest peaks, and observe the following three regimes: a small Froude number pattern, in which the divergent waves are not visible; standard wave patterns for which the maximum peaks o...

  9. Gas sensing characterization of tellurium thin films by the Kelvin probe technique

    International Nuclear Information System (INIS)

    The sensing behavior of tellurium films at room temperature was tested with environmental pollutant gases, such as NO2, CO, O3, and water vapor, using the Kelvin probe technique. A significant sensitivity was observed for nitrogen dioxide. The detection range for NO2 was between 0.5-5.0 ppm in air with controlled humidity. The response and the recovery time are rapid with good reproducibility and high sensibility. The work function measurements showed that chalcogenide semiconductors in question are well-suited materials for the detection of not only small concentrations of NO2, but also for humidity sensing. The relative humidity of 45% induces the work function change Δ φ of approximately 200 mV at room temperature. It is shown that the 'strong' chemisorption of nitrogen dioxide results in an increase in both work function change Δ Φ > 0 and electrical conductivity Δ c > 0 because of the additional charging of the surface and band bending. The effect of water vapor is due to a simple physical adsorption of polar water molecules oriented perpendicular to the surface with a negative pole inward. As a result, the dipole component of the work function increases, i.e., Δ Φ > 0, but the free lattice holes become more localized at the surface and the conductivity of the p-type chalcogenide layer decreases Δ c < 0. (authors)

  10. Electron-phonon coupling in bilayer and single-layer graphene at sub-Kelvin temperatures

    Science.gov (United States)

    McKitterick, Chris; Vora, Heli; Du, Xu; Rooks, Michael; Prober, Daniel

    2014-03-01

    Graphene has been proposed by many groups as a detector of terahertz photons1 , 2 , 3, due to its very small heat capacity and predicted low thermal conductance. We present Johnson noise thermometry measurements of single and bilayer graphene samples fabricated at Stony Brook University and at Yale University. These measurements probe the graphene electron-phonon coupling at sub-Kelvin temperatures. The devices are fabricated with superconducting contacts (NbN at Stony Brook, Al and Nb at Yale) to confine the hot electrons in the graphene device, diminishing the contribution of electron out-diffusion in cooling the electron system. By using commercially-available CVD-grown graphene for some samples, we can define large area sections, allowing us to emphasize the thermal conductance due to electron-phonon coupling. These measurements allow for performance estimates for using similar graphene devices to detect terahertz photons. 1C. B. McKitterick, D. E. Prober, B. S. Karasik, Journal of Applied Physics 113, 044512 (2013). 2H. Vora, P. Kumaravadivel, B. Nielsen, X. Du, Applied Physics Letters 100, 153507 (2012). 3K. Fong, K. Schwab, Physical Review X 2, 1 (2012). This work supported by NSF-DMR 0907082.

  11. The effect of compressibility on magnetohydrodynamic jets and Kelvin-Helmholtz instability

    Science.gov (United States)

    Praturi, Divya Sri; Girimaji, Sharath

    2015-11-01

    We investigate the effect of compressibility and magnetic field on the evolution of planar magnetohydrodynamic (MHD) jets. These jets are susceptible to Kelvin-Helmholtz (KH) instability when subjected to an in-plane transverse velocity perturbation. Various linear stability analyses have shown that compressibility and magnetic field along the jet have a stabilizing influence on the KH instability. We performed three-dimensional numerical simulations using magneto gas kinetic method (MGKM) to study the effect of the Mach number, Alfvén Mach number, and the orientation of the magnetic field with respect to the jet velocity direction on the flow-field evolution. In MGKM, the magnetic effects are added as source terms in the hydrodynamic gas kinetic scheme which also take into account the non-ideal MHD terms for finite plasma conductivity and the Hall effects. An in-depth analysis of linear and nonlinear physics is presented. The first author was supported by Texas A&M University Institute for Advanced Study HEEP fellowship.

  12. Kint3-4 protein from human plasminogen delays Ehrlich tumor growth in mice Efeito da proteína Kint3-4 do plasminogênio humano no crescimento do tumor de Ehrlich

    Directory of Open Access Journals (Sweden)

    Cristina Maria de Souza

    2011-08-01

    Full Text Available INTRODUCTION AND OBJECTIVE: Kint3-4 protein, originated from a genetic recombination of K1-3 and K1-4 human plasminogen segments, is recognized for its antiangiogenic and anti-inflammatory potential. This study aimed to evaluate the effect of Kint3-4 protein on tumor development in Swiss mice previously inoculated with Ehrlich tumor cells. METHODS: The protein fragment was obtained from Pichia pastoris cloning and transformation. After tumor cell inoculation three different protocols were used to assess tumor growth: beginning (0-6 days, peak (0-12 days and after peak (0-18 days. We analyzed tumor growth, histomorphological characteristics and immunohistochemistry by use of CDC47 (cellular proliferation marker and CD31 (blood vessel marker. RESULTS: Animals treated with Kint3-4 protein (150 µg/kg/48 h showed lower tumor growth in all protocols. Based on histological assessment, inflammation and tumor areas were also reduced. Moreover, both the lowest rate of tumor cell proliferation and low microvessel density were observed in animals treated with Kint3-4 protein compared with the untreated control group. CONCLUSION: The effect of Kint3-4 recombinant protein on tumor angiogenesis and control of malignant cell proliferation enhances the prospects of its use in clinical and antiangiogenic treatment.INTRODUÇÃO E OBJETIVO: A proteína Kint3-4 originou-se a partir de uma recombinação genética dos segmentos K1-3 e K1--4 do plasminogênio humano e é reconhecida por seu potencial anti-inflamatório e antiangiogênico. Este estudo teve como objetivo avaliar o efeito da proteína Kint3-4 no desenvolvimento de tumores em camundongos inoculados com células do tumor de Ehrlich. MÉTODOS: O fragmento de proteína foi obtido por uma técnica de clonagem e transformação de Pichia pastoris. Três diferentes protocolos foram avaliados após a inoculação das células tumorais: no início (0-6 dias, no pico (0-12 dias e após o pico (0-18 dias de

  13. Valentine’s Day

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>February 14 is a day for people who have fallen in love.On this day, these men and women give gifts(presents) and cards to each other for Valentine’s Day(情人节). This day has been popular with people in love for a long time.At first,this holiday was called Lupercalia. Then the name of the day was changed to Saint Valentine’s Day.The man named Saint Valentine was killed on February 14,270 AD,because he was a Christian(基督教徒).

  14. The effect of oxidation on charge carrier motion in PbS quantum dot thin films studied with Kelvin Probe Microscopy

    Science.gov (United States)

    Nguyen Hoang, Lan Phuong; Williams, Pheona; Moscatello, Jason; Aidala, Kathy; Aidala group Team

    We developed a technique that uses scanning probe microscopy (SPM) to study the real-time injection and extraction of charge carriers in thin film devices. We investigate the effects of oxidation on thin films of Lead Sulfide (PbS) quantum dots with tetrabutyl-ammonium-iodide (TBAI) ligands in an inverted field effect transistor geometry with gold electrodes. By positioning the SPM tip at an individual location and using Kelvin Probe Force Microscopy (KPFM) to measure the potential over time, we can record how the charge carriers respond to changing the backgate voltage with grounded source and drain electrodes. We see relatively fast screening for negative backgate voltages because holes are quickly injected into the PbS film. The screening is slower for positive gate voltages, because some of these holes are trapped and therefore less mobile. We probe these trapped holes by applying different gate voltages and recording the change in potential at the surface. There are mixed reports about the effect of air exposure on thin films of PbS quantum dots, with initial exposure appearing to be beneficial to device characteristics. We study the change in current, mobility, and charge injection and extraction as measured by KPFM over hours and days of exposure to air. This work is supported by NSF Grant DMR-0955348, and the Center for Heirarchical Manufacturing at the University of Massachusetts, Amherst (NSF CMMI-1025020).

  15. Mephedrone, methylone and 3,4-methylenedioxypyrovalerone (MDPV) induce conditioned place preference in mice.

    Science.gov (United States)

    Karlsson, Louise; Andersson, Mikael; Kronstrand, Robert; Kugelberg, Fredrik C

    2014-11-01

    During the last decade, there has been a worldwide increase in popularity and abuse of synthetic cathinones. Common ingredients of the so-called bath salts include mephedrone, methylone and 3,4-methylenedioxypyrovalerone (MDPV). Relatively little information about the pharmacology and addiction potential of these drugs is available. We used the conditioned place preference (CPP) paradigm to explore the reinforcing effects of three different synthetic cathinones. The primary aim of this study was to investigate whether mephedrone, methylone and MDPV induce CPP in mice. The secondary aims were to investigate a possible dose-response CPP and whether the synthetic cathinones induce higher CPP than amphetamine at equal dose. C57BL/6 mice were conditioned to mephedrone, methylone, MDPV and amphetamine at doses of 0.5, 2, 5, 10 or 20 mg/kg (i.p.). During the conditioning, the mice received two training sessions per day for 4 days. All four tested drugs showed a significant place preference compared with controls. Mice conditioned with MDPV (5 and 10 mg/kg) displayed a greater preference score compared to mice conditioned with amphetamine (5 and 10 mg/kg). Our findings show that mephedrone, methylone and MDPV produce CPP equal or higher than amphetamine strongly suggesting addictive properties. Given the public health concern of abuse, future pharmacological studies are necessary to fully understand the effects of these drugs.

  16. Day Care Centers

    Data.gov (United States)

    Department of Homeland Security — This database contains locations of day care centers for 50 states and Washington D.C. and Puerto Rico. The dataset only includes center based day care locations...

  17. Simultaneous polysubstance use among Danish 3,4-methylenedioxymethamphetamine and hallucinogen users

    DEFF Research Database (Denmark)

    Licht, Cecilie L; Christoffersen, Maria; Okholm, Mads;

    2012-01-01

    To describe patterns of simultaneous polysubstance use (SPU) among Danish 3,4-methylenedioxymethamphetamine (MDMA) ("Ecstasy") and hallucinogen users.......To describe patterns of simultaneous polysubstance use (SPU) among Danish 3,4-methylenedioxymethamphetamine (MDMA) ("Ecstasy") and hallucinogen users....

  18. Is day surgery safe?

    DEFF Research Database (Denmark)

    Majholm, Birgitte; Engbæk, J; Bartholdy, Jens;

    2012-01-01

    Day surgery is expanding in several countries, and it is important to collect information about quality. The aim of this study was to assess morbidity and unanticipated hospital visits 0-30 days post-operatively in a large cohort.......Day surgery is expanding in several countries, and it is important to collect information about quality. The aim of this study was to assess morbidity and unanticipated hospital visits 0-30 days post-operatively in a large cohort....

  19. 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of [3H]paroxetine-labeled serotonin uptake sites

    International Nuclear Information System (INIS)

    This study examines the effects of repeated systemic administration (20 mg/kg s.c., twice daily for 4 days) of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) on levels of brain monoamines, their metabolites and on the density of monoamine uptake sites in various regions of rat brain. Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid were observed in cerebral cortex, hippocampus, striatum, hypothalamus and midbrain at 2 weeks after a 4-day treatment regimen of MDMA or MDA; less consistent reductions in serotonin (5-HT) content were observed in these brain regions. In addition, both MDMA and MDA caused comparable and substantial reductions (50-75%) in the density of [3H]paroxetine-labeled 5-HT uptake sites in all brain regions examined. In contrast, neither MDMA nor MDA caused any widespread or long-term changes in the content of the catecholaminergic markers (i.e., norepinephrine, dopamine, 3,4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of [3H]mazindol-labeled norepinephrine or dopamine uptake sites in the brain regions examined. These data demonstrate that MDMA and MDA cause long-lasting neurotoxic effects with respect to both the functional and structural integrity of serotonergic neurons in brain. Furthermore, our measurement of reductions in the density of 5-HT uptake sites provides a means for quantification of the neurodegenerative effects of MDMA and MDA on presynaptic 5-HT terminals

  20. 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of (/sup 3/H)paroxetine-labeled serotonin uptake sites

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, G.; Yeh, S.Y.; O' Hearn, E.; Molliver, M.E.; Kuhar, M.J.; De Souza, E.B.

    1987-09-01

    This study examines the effects of repeated systemic administration (20 mg/kg s.c., twice daily for 4 days) of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) on levels of brain monoamines, their metabolites and on the density of monoamine uptake sites in various regions of rat brain. Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid were observed in cerebral cortex, hippocampus, striatum, hypothalamus and midbrain at 2 weeks after a 4-day treatment regimen of MDMA or MDA; less consistent reductions in serotonin (5-HT) content were observed in these brain regions. In addition, both MDMA and MDA caused comparable and substantial reductions (50-75%) in the density of (/sup 3/H)paroxetine-labeled 5-HT uptake sites in all brain regions examined. In contrast, neither MDMA nor MDA caused any widespread or long-term changes in the content of the catecholaminergic markers (i.e., norepinephrine, dopamine, 3,4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of (/sup 3/H)mazindol-labeled norepinephrine or dopamine uptake sites in the brain regions examined. These data demonstrate that MDMA and MDA cause long-lasting neurotoxic effects with respect to both the functional and structural integrity of serotonergic neurons in brain. Furthermore, our measurement of reductions in the density of 5-HT uptake sites provides a means for quantification of the neurodegenerative effects of MDMA and MDA on presynaptic 5-HT terminals.

  1. The SAO and Kelvin waves in the EuroGRIPS GCMS and the UK Met. Office analyses

    Directory of Open Access Journals (Sweden)

    M. Amodei

    Full Text Available We compare the tropical oscillations and planetary scale Kelvin waves in four troposphere-stratosphere climate models and the assimilated dataset produced by the United Kingdom Meteorological Office (UKMO. The comparison has been made in the GRIPS framework "GCM-Reality Intercomparison Project for SPARC", where SPARC is Stratospheric Processes and their Role in Climate, a project of the World Climate Research Program. The four models evaluated are European members of GRIPS: the UKMO Unified Model (UM, the model of the Free University in Berlin (FUB–GCM, the ARPEGE-climat model of the French National Centre for Meteorological Research (CNRM, and the Extended UGAMP GCM (EUGCM of the Centre for Global Atmospheric Modelling (CGAM. The integrations were performed with different, but annually periodic external conditions (e.g., sea-surface temperature, sea ice, and incoming solar radiation. The structure of the tropical winds and the strengths of the Kelvin waves are examined. In the analyses where the SAO (Semi-Annual Oscillation and the QBO (Quasi-Biennal Oscillation are reasonably well captured, the amplitude of these analysed Kelvin waves is close to that observed in independent data from UARS (Upper Atmosphere Research Satellite. In agreement with observations, the Kelvin waves generated in the models propagate into the middle atmosphere as wave packets, consistent with a convective forcing origin. In three of the models, slow Kelvin waves propagate too high and their amplitudes are overestimated in the upper stratosphere and in the mesosphere, the exception is the UM which has weaker waves. None of the modelled waves are sufficient to force realistic eastward phases of the QBO or SAO. Although the SAO is represented by all models, only two of them are able to generate westerlies between 10 hPa and 50 hPa. The importance of the role played in the SAO by unresolved gravity waves is emphasized. Although it exhibits some unrealistic features, the

  2. Valentine’s Day

    Institute of Scientific and Technical Information of China (English)

    顾晓玲

    2009-01-01

    Valentine’s Day, which falls on February 14, is one of the most popular festivals of western society and even the whole world. It is a day for lovers, a day when people present chocolates, cards and candies to their beloved (心爱的人).

  3. April Fools’ Day

    Institute of Scientific and Technical Information of China (English)

    Abby

    2009-01-01

    April Fools’ Day,the day when mischief-makers(恶作剧的人)are ever so indulged(纵容),falls on April 1 every year.On that day,various pranks(恶作剧)are played on one another,and everybody has to be

  4. A Day to Celebrate

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Participating countries at the 2010 World Expo in Shanghai can choose a day as their National Pavilion Day.The day is usually celebrated with ceremonies and performances,which bring the nation’s culture and its character to life.

  5. Slimmed May Day Holiday

    Institute of Scientific and Technical Information of China (English)

    Liu Xinwen

    2008-01-01

    @@ Last November the State Council of China decided to renew its holiday system by reducing the seven-day Mav Dav holiday to three days and introducing three new one-day public holidays,namely the Qingming Festival,Dragon Boat Festival and Moon Festival.BY doing so,the three golden-week holidays that were introduced in 1999,namely the Spring Festival,Mav Dav and National Day,could be better distributed.The New Year's Eve holiday would remain one day.The new holiday plan was supposed to take effect in 2008.

  6. Novel 2,5-disubstituted-1,3,4-oxadiazoles as anti-inflammatory drugs

    Directory of Open Access Journals (Sweden)

    Ega Durgashivaprasad

    2014-01-01

    Full Text Available Objective: 1,3,4-oxadiazole ring is a versatile moiety with a wide range of pharmacological properties. The present work deals with the synthesis and evaluation of the anti-inflammatory activity of two novel 2,5-disubstituted-1,3,4-oxadiazoles (OSD and OPD. Materials and Methods: Carrageenan-induced rat hind paw edema was employed as an acute model of inflammation. For evaluating sub-acute anti-inflammatory activity, carrageenan-induced inflammation in rat air pouch was employed. Complete Freund′s adjuvant-induced arthritis in rats was used as a model of chronic inflammation. To evaluate in vitro anti-inflammatory activity, lipopolysaccharide (LPS-stimulated RAW264.7 cells were used. Results: OSD (100 mg/kg reduced carrageen-induced paw edema by 60%, and OPD (100 mg/kg produced a modest 32.5% reduction. OSD also reduced leukocyte influx and myeloperoxidase in carrageenan-induced rat air pouch model. In complete Freund′s adjuvant-induced arthritis model, both OSD and OPD (200 mg/kg for 14 days reduced paw edema and NO levels. In LPS-stimulated RAW264.7 cells, OSD and OPD inhibited formation of nitric oxide and reactive oxygen species, with OPD showing a better activity in comparison to OSD. Conclusions: OSD was the better of the two compounds in in vivo models of inflammation. The o-phenol substitution at position 2 of oxadiazole ring in OSD may be responsible for its better in vivo anti-inflammatory activity. The ability of the compounds to inhibit LPS-induced pro-inflammatory mediator release suggests an anti-inflammatory mechanism targeting LPS-TLR4-NF-κB signalling pathway, which needs to be explored in detail. The disparate efficacy in vitro and in vivo also requires in-depth evaluation of the pharmacokinetics of these novel oxadiazoles.

  7. Popular Chat Day Q & A

    Science.gov (United States)

    ... Popular Chat Day Q & A Popular Chat Day Q & A Read students’ most popular questions about drug ... Day Chat Day Participant FAQs Popular Chat Day Q & A Search Chat Day Transcripts Past Chat Day ...

  8. Metformin Prevented Dopaminergic Neurotoxicity Induced by 3,4-Methylenedioxymethamphetamine Administration.

    Science.gov (United States)

    Porceddu, Pier Francesca; Ishola, Ismail Ogunbayode; Contu, Liliana; Morelli, Micaela

    2016-07-01

    Metformin, a well-known antidiabetic drug, has recently been proposed to promote neurogenesis and to have a neuroprotective effect on the neurodegenerative processes induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in models of Parkinson's disease. Interestingly, metformin has antioxidant properties and is involved in regulating the production of cytokines released during the neuroinflammatory process. Several studies have reported that 3,4-methylenedioxymethamphetamine (MDMA), a recreational drug mostly consumed by young adults, produces a persistent loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) and caudate putamen (CPu) of mice. The aim of this study was to investigate the potential neuroprotective effect of metformin against short- and long-term neurotoxicity induced by MDMA and its role on MDMA-induced hyperthermia. Adult mice received metformin (2 × 200 mg/kg, 11-h intervals, administered orally), MDMA (4 × 20 mg/kg, 2-h interval, administered intraperitoneally), or MDMA plus metformin (2 × 200 mg/kg, 1 h before the first MDMA administration and 4 h after the last). On the second and third day, mice were treated with vehicle or metformin (1 × 200 mg/kg) and sacrificed 48 h and 7 days after the last MDMA administration. The neuroprotective effect of metformin on MDMA-induced dopaminergic damage was evaluated by dopamine transporter (DAT) and tyrosine hydroxylase (TH) immunohistochemistry in SNc and CPu. Metformin prevented the MDMA-induced loss of TH-positive neurons in the SNc and TH- and DAT-positive fibers in CPu, both at 48 h and 7 days after the last MDMA administration. These results show that metformin is neuroprotective against the short- and long-lasting dopaminergic neurodegeneration induced by MDMA. PMID:27251371

  9. Biodegradation of 3,4 dichloroaniline by fungal isolated from the preconditioning phase of winery wastes subjected to vermicomposting.

    Science.gov (United States)

    Castillo, Jean Manuel; Nogales, Rogelio; Romero, Esperanza

    2014-02-28

    A hazardous contaminant, 3,4-dichloroaniline (DCA) is widespread in the environment due to its extensive use in the manufacture of chemicals and its application in different sectors. The ability of fungi grow on in winery wastes in the preconditioning period of vermicomposting to degrade DCA was investigated. Three filamentous fungi (F1, F2, and F3) were isolated and one identified as Aspergillus niger and two as Fusarium sp. strains. The culture media with the fungus alone or in consortium (Fmix) with DCA as the nitrogen source were analyzed by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC/MS). The fastest degradation rate was measured in Fmix with a DT50 of 0.85day(-1). Fusarium sp. and A. niger differed in the metabolism of DCA. Five metabolites were identified as a result of oxidation, co-denitrification, N-acetylation, and polymerization reactions. The major metabolites were 3,4-dichloroacetanilide and dichloroquinolines. The azo-metabolites tetrachloroazobenzene and tetracloroazoxybenzene and 3,4-dichloronitrobenzene were found in minor amounts but appeared to be the most persistent in the Fusarium cultures (half-lives ranging from 8.3 to 30.9 days). This study highlights the metabolic potential of microorganisms in the preconditioning period of the vermicomposting process and its possible application for in situ bioremediation strategies. PMID:24440653

  10. Biodegradation of 3,4 dichloroaniline by fungal isolated from the preconditioning phase of winery wastes subjected to vermicomposting.

    Science.gov (United States)

    Castillo, Jean Manuel; Nogales, Rogelio; Romero, Esperanza

    2014-02-28

    A hazardous contaminant, 3,4-dichloroaniline (DCA) is widespread in the environment due to its extensive use in the manufacture of chemicals and its application in different sectors. The ability of fungi grow on in winery wastes in the preconditioning period of vermicomposting to degrade DCA was investigated. Three filamentous fungi (F1, F2, and F3) were isolated and one identified as Aspergillus niger and two as Fusarium sp. strains. The culture media with the fungus alone or in consortium (Fmix) with DCA as the nitrogen source were analyzed by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC/MS). The fastest degradation rate was measured in Fmix with a DT50 of 0.85day(-1). Fusarium sp. and A. niger differed in the metabolism of DCA. Five metabolites were identified as a result of oxidation, co-denitrification, N-acetylation, and polymerization reactions. The major metabolites were 3,4-dichloroacetanilide and dichloroquinolines. The azo-metabolites tetrachloroazobenzene and tetracloroazoxybenzene and 3,4-dichloronitrobenzene were found in minor amounts but appeared to be the most persistent in the Fusarium cultures (half-lives ranging from 8.3 to 30.9 days). This study highlights the metabolic potential of microorganisms in the preconditioning period of the vermicomposting process and its possible application for in situ bioremediation strategies.

  11. AGR-3/4 Final Data Qualification Report for ATR Cycles 151A through 155B-1

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Binh T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    This report provides the qualification status of experimental data for the entire Advanced Gas Reactor 3/4 (AGR 3/4) fuel irradiation. AGR-3/4 is the third in a series of planned irradiation experiments conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for the AGR Fuel Development and Qualification Program, which supports development of the advanced reactor technology under the INL ART Technology Development Office (TDO). The main objective of AGR-3/4 irradiation is to provide a known source of fission products for subsequent transport through compact matrix and structural graphite materials due to the presence of designed-to-fail fuel particles. Full power irradiation of the AGR 3/4 test began on December 14, 2011 (ATR Cycle 151A), and was completed on April 12, 2014 (end of ATR Cycle 155B) after 369.1 effective full power days of irradiation. The AGR-3/4 test was in the reactor core for eight of the ten ATR cycles between 151A and 155B. During the unplanned outage cycle, 153A, the experiment was removed from the ATR northeast flux trap (NEFT) location and stored in the ATR canal. This was to prevent overheating of fuel compacts due to higher than normal ATR power during the subsequent Powered Axial Locator Mechanism cycle, 153B. The AGR 3/4 test was inserted back into the ATR NEFT location during the outage of ATR Cycle 154A on April 26, 2013. Therefore, the AGR-3/4 irradiation data received during these 2 cycles (153A and 153B) are irrelevant and their qualification status isnot included in this report. Additionally, during ATR Cycle 152A the ATR core ran at low power for a short enough duration that the irradiation data are not used for physics and thermal calculations. However, the qualification status of irradiation data for this cycle is still covered in this report. As a result, this report includes data from 8 ATR Cycles: 151A, 151B, 152A, 152B, 154A, 154B, 155A, and 155B, as recorded in the Nuclear Data Management and

  12. 1,3,4,6,7,9-Hexamethylbenzo[1,2-c:3,4-c':5,6-c'']trithiophene: a twisted heteroarene.

    Science.gov (United States)

    Wu, Yao-Ting; Tai, Chia-Cheng; Lin, Wei-Chih; Baldridge, Kim K

    2009-07-01

    1,3,4,6,7,9-Hexamethylbenzo[1,2-c:3,4-c':5,6-c'']trithiophene (C-Me) was prepared by palladium-catalyzed methylations of the corresponding hexabromide C-Br. The twisted structure of C-Me has been confirmed by X-ray crystal analysis. The physical properties of twisted C-Me and planar benzo[1,2-c:3,4-c':5,6-c'']trithiophene (C-H) were studied and compared. Crystal structures are compared to computational structures determined using density functional theory, with both the M06-2X and B3PW91 functionals.

  13. Instability of Supersonic Cold Streams Feeding Galaxies I: Linear Kelvin-Helmholtz Instability with Body Modes

    Science.gov (United States)

    Mandelker, Nir; Padnos, Dan; Dekel, Avishai; Birnboim, Yuval; Burkert, Andreas; Krumholz, Mark R.; Steinberg, Elad

    2016-09-01

    Massive galaxies at high redshift are predicted to be fed from the cosmic web by narrow, dense streams of cold gas that penetrate through the hot medium encompassed by a stable shock near the virial radius of the dark-matter halo. Our long-term goal is to explore the heating and dissipation rate of the streams and their fragmentation and possible breakup, in order to understand how galaxies are fed, and how this affects their star-formation rate and morphology. We present here the first step, where we analyze the linear Kelvin-Helmholtz instability (KHI) of a cold, dense slab or cylinder in 3D flowing supersonically through a hot, dilute medium. The current analysis is limited to the adiabatic case with no gravity. By analytically solving the linear dispersion relation, we find a transition from a dominance of the familiar rapidly growing surface modes in the subsonic regime to more slowly growing body modes in the supersonic regime. The system is parametrized by three parameters: the density contrast between stream and medium, the Mach number of stream velocity with respect to the medium, and the stream width with respect to the halo virial radius. A realistic choice for these parameters places the streams near the mode transition, with the KHI exponential-growth time in the range 0.01-10 virial crossing times for a perturbation wavelength comparable to the stream width. We confirm our analytic predictions with idealized hydrodynamical simulations. Our linear estimates thus indicate that KHI may be effective in the evolution of streams before they reach the galaxy. More definite conclusions await the extension of the analysis to the nonlinear regime and the inclusion of cooling, thermal conduction, the halo potential well, self-gravity and magnetic fields.

  14. The Fourier-Kelvin Stellar Interferometer (FKSI): A Discovery Class TPF/DARWIN Pathfinder Mission Concept

    Science.gov (United States)

    Danchi, W. C.; Allen, R. J.; Benford, D. J.; Deming, D.; Gezan, D. Y.; Kuchner, M.; Leisawitz, D. T.; Linfield, R.; Millan-Gabet, R.; Monnier, J. D.

    2003-01-01

    The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer for the mid-infrared spectral region (5-30 microns). FKSI is conceived as a scientific and technological pathfinder to TPF/DARWIN as well as SPIRIT, SPECS, and SAFIR. It will also be a high angular resolution system complementary to NGST. The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will also search for brown dwarfs and Jupiter mass and smaller planets, and could also play a very powerful role in the investigation of the structure of active galactic nuclei and extra-galactic star formation. We have been studying alternative interferometer architectures and beam combination techniques, and evaluating the relevant science and technology tradeoffs. Some of the technical challenges include the development of the cryocooler systems necessary for the telescopes and focal plane array, light and stiff but well-damped truss systems to support the telescopes, and lightweight and coolable optical telescopes. We present results of detailed design studies of the FKSI starting with a design consisting of five one meter diameter telescopes arranged along a truss structure in a linear non-redundant array, cooled to 35 K. A maximum baseline of 20 meters gives a nominal resolution of 26 mas at 5 microns. Using a Fizeau beam combination technique, a simple focal plane camera could be used to obtain both Fourier and spectral data simultaneously for a given orientation of the array. The spacecraft will be rotated to give sufficient Fourier data to reconstruct complex images of a broad range of astrophysical sources. Alternative and simpler three and two telescope designs emphasizing nulling and spectroscopy also have been

  15. Evolution of Kelvin-Helmholtz instability at Venus in the presence of the parallel magnetic field

    International Nuclear Information System (INIS)

    Two-dimensional MHD simulations were performed to study the evolution of the Kelvin-Helmholtz (KH) instability at the Venusian ionopause in response to the strong flow shear in presence of the in-plane magnetic field parallel to the flow direction. The physical behavior of the KH instability as well as the triggering and occurrence conditions for highly rolled-up vortices are characterized through several physical parameters, including Alfvén Mach number on the upper side of the layer, the density ratio, and the ratio of parallel magnetic fields between two sides of the layer. Using these parameters, the simulations show that both the high density ratio and the parallel magnetic field component across the boundary layer play a role of stabilizing the instability. In the high density ratio case, the amount of total magnetic energy in the final quasi-steady status is much more than that in the initial status, which is clearly different from the case with low density ratio. We particularly investigate the nonlinear development of the case that has a high density ratio and uniform magnetic field. Before the instability saturation, a single magnetic island is formed and evolves into two quasi-steady islands in the non-linear phase. A quasi-steady pattern eventually forms and is embedded within a uniform magnetic field and a broadened boundary layer. The estimation of loss rates of ions from Venus indicates that the stabilizing effect of the parallel magnetic field component on the KH instability becomes strong in the case of high density ratio

  16. Electrical Potential of Acupuncture Points: Use of a Noncontact Scanning Kelvin Probe

    Directory of Open Access Journals (Sweden)

    Brian J. Gow

    2012-01-01

    Full Text Available Objective. Acupuncture points are reportedly distinguishable by their electrical properties. However, confounders arising from skin-to-electrode contact used in traditional electrodermal methods have contributed to controversies over this claim. The Scanning Kelvin Probe is a state-of-the-art device that measures electrical potential without actually touching the skin and is thus capable of overcoming these confounding effects. In this study, we evaluated the electrical potential profiles of acupoints LI-4 and PC-6 and their adjacent controls. We hypothesize that acupuncture point sites are associated with increased variability in potential compared to adjacent control sites. Methods. Twelve healthy individuals were recruited for this study. Acupuncture points LI-4 and PC-6 and their adjacent controls were assessed. A 2 mm probe tip was placed over the predetermined skin site and adjusted to a tip-to-sample distance of 1.0 mm under tip oscillation settings of 62.4 Hz frequency. A surface potential scan spanning a 1.0 cm × 1.0 cm area was obtained. Results. At both the PC-6 and LI-4 sites, no significant differences in mean potential were observed compared to their respective controls (Wilcoxon rank-sum test, and 0.79, resp.. However, the LI-4 site was associated with significant increase in variability compared to its control as denoted by standard deviation and range ( and 0.0005, resp.. At the PC-6 site, no statistical differences in variability were observed. Conclusion. Acupuncture points may be associated with increased variability in electrical potential.

  17. Modulation of the Convectively Coupled Kelvin Waves by the Madden-Julian Oscillation

    Science.gov (United States)

    Guo, Y.; Jiang, X.; Waliser, D. E.

    2013-12-01

    As one of the major tropical wave modes, the convectively-coupled equatorial Kelvin wave (CCKW) plays a critical role in tropical climate / weather variability. CCKW activity exhibits strong variation on both seasonal and intraseasonal time scales. In this study, evidence of the strong modulation of the CCKW activity by the Madden-Julian Oscillation (MJO) will be presented, with a particular focus over South America and tropical Atlantic region. The primary modulation of CCKWs over this region, as noted in anomalous fields of rainfall as well as vertical profiles of wind, moisture and temperature, is found to be a modulation of wave activity - namely amplitude, with secondary effects on vertical structure, and very little impact on wavenumber. CCKW activity is enhanced during MJO phases 8, 1, and 2, and damped during MJO phases 4, 5, and 6. Further analyses reveal that the strong modulation of the MJO on the CCKW activity could be largely through two factors, namely, the vertical zonal wind shear and the lower-middle troposphere specific humidity. The CCKW activity tends to be enhanced during MJO phases when the westward vertical wind shear and positive lower to mid-troposphere moisture anomalies are evident, and vice versa. These two physical processes associated with the MJO are found to have positively (negatively) reinforcing influences in the CCKW activity in phase 1 (4, and 5), while counteracting influences in phases 2, 3, 6, 7, and 8, leading to the observed MJO cycle of the CCKW activity anomalies in the study region. The results presented in this study may have important implications for extended-range prediction of tropical wave activity, and possibly initiation of the MJO further downstream in the Indian Ocean.

  18. Evolution of Kelvin-Helmholtz instability at Venus in the presence of the parallel magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Lu, H. Y. [Space Science Institute, School of Astronautics, Beihang University, Beijing 100191 (China); Key Laboratory of Planetary Sciences, Chinese Academy of Sciences, Nanjing 210008 (China); Cao, J. B.; Fu, H. S. [Space Science Institute, School of Astronautics, Beihang University, Beijing 100191 (China); Zhang, T. L. [Space Research Institute, Austrian Academy of Sciences, Graz A-8042 (Austria); Ge, Y. S. [Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

    2015-06-15

    Two-dimensional MHD simulations were performed to study the evolution of the Kelvin-Helmholtz (KH) instability at the Venusian ionopause in response to the strong flow shear in presence of the in-plane magnetic field parallel to the flow direction. The physical behavior of the KH instability as well as the triggering and occurrence conditions for highly rolled-up vortices are characterized through several physical parameters, including Alfvén Mach number on the upper side of the layer, the density ratio, and the ratio of parallel magnetic fields between two sides of the layer. Using these parameters, the simulations show that both the high density ratio and the parallel magnetic field component across the boundary layer play a role of stabilizing the instability. In the high density ratio case, the amount of total magnetic energy in the final quasi-steady status is much more than that in the initial status, which is clearly different from the case with low density ratio. We particularly investigate the nonlinear development of the case that has a high density ratio and uniform magnetic field. Before the instability saturation, a single magnetic island is formed and evolves into two quasi-steady islands in the non-linear phase. A quasi-steady pattern eventually forms and is embedded within a uniform magnetic field and a broadened boundary layer. The estimation of loss rates of ions from Venus indicates that the stabilizing effect of the parallel magnetic field component on the KH instability becomes strong in the case of high density ratio.

  19. Kelvin Absolute Temperature Scale Identified as Length Scale and Related to de Broglie Thermal Wavelength

    Science.gov (United States)

    Sohrab, Siavash

    Thermodynamic equilibrium between matter and radiation leads to de Broglie wavelength λdβ = h /mβvrβ and frequency νdβ = k /mβvrβ of matter waves and stochastic definitions of Planck h =hk =mk c and Boltzmann k =kk =mk c constants, λrkνrk = c , that respectively relate to spatial (λ) and temporal (ν) aspects of vacuum fluctuations. Photon massmk =√{ hk /c3 } , amu =√{ hkc } = 1 /No , and universal gas constant Ro =No k =√{ k / hc } result in internal Uk = Nhνrk = Nmkc2 = 3 Nmkvmpk2 = 3 NkT and potential pV = uN\\vcirc / 3 = N\\ucirc / 3 = NkT energy of photon gas in Casimir vacuum such that H = TS = 4 NkT . Therefore, Kelvin absolute thermodynamic temperature scale [degree K] is identified as length scale [meter] and related to most probable wavelength and de Broglie thermal wavelength as Tβ =λmpβ =λdβ / 3 . Parallel to Wien displacement law obtained from Planck distribution, the displacement law λwS T =c2 /√{ 3} is obtained from Maxwell -Boltzmann distribution of speed of ``photon clusters''. The propagation speeds of sound waves in ideal gas versus light waves in photon gas are described in terms of vrβ in harmony with perceptions of Huygens. Newton formula for speed of long waves in canals √{ p / ρ } is modified to √{ gh } =√{ γp / ρ } in accordance with adiabatic theory of Laplace.

  20. Preparation of QTi4.3-4Graghite Composite by Semi-solid Casting Technology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; DU Yunhui; LIU Hanwu; ZENG Daben; BA Limin

    2005-01-01

    The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry, and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared using the semi-solid casting technology successfully. The structure of this QTi4.3-4 graghite composite was studied and the condition for uniform distribution of graphite particles was got. The experimental results show that there exists a linear relationship between the solid fraction aud the stirring temperature of QTi4.3-4 graphite slurry. With the decreasing of stirring temperature, the solid fraction of QTi4.3-4 graghite slurry increases constantly. In casting, with the iucreasing of solid fraction of QTi4.3-4graghite slurry, the agglomeration of graphite particles is removed gradually. When the solid fraction is higher than 40% , graphite particles can distribute evenly in QTi4.3-4 graghite composite.

  1. General Rushes Open Days Day II

    CERN Multimedia

    2013-01-01

    General Footage during the Open Days 2013 (Day 2 -29/09/2013) Images: Antoine Nouel, Clément Sbaffe, Victor Prunier, David Guerazzi, Basile Manent, Réemi Richarme, Noemi Caraban 00:00:00 00:08:56 Interviews 00:08:56 00:20:47 ALICE 00:20:47 00:26:52 ATLAS 00:26:52 00:28:07 Workshops 00:28:07 00:33:13 Crystal Lab 00:33:13 00:44:19 Superconductivity 00:44:19 01:04:42 Cryogenics 01:04:42 01:12:39 Transports 01:12:39 01:16:30 LEIR 01:16:30 01:18:28 LMF 01:18:28 01:19:50 Vacuum 01:19:50 01:36:39 Superconducting magnets (F1) 01:36:39 01:46:06 The idea filled world of vacuum (F2) 01:46:06 01:49:55 CCC 01:49:55 01:52:41 Safety Training Center 01:52:41 01:55:00 COMPASS 01:55:00 02:09:19 Robotics 02:09:19 02:18:36 LHC Point 6 (with DG) 02:18:36 02:25:16 LHC Point 4 02:25:16 02:29:29 LHCb 02:29:29 02:33:12 Control Center 02:33:12 02:39:57 Streets

  2. AAS 227: Day 4

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    mean its not typical. While we wait for more and better observations of exoplanet systems, theory can help us understand why the Solar System formed the way it did, and where to look for systems that formed the same way. For example, some of Murray-Clays previous work has shown that metal-rich stars tend to host more hot Jupiters and eccentric giant planets (very different from Solar System architecture). So if we want to find more systems like our own, we need to search around stars with low-to-moderate metallicity.Extrasolar Planets: Hosts, Interactions, Formation, and Interiors (by Caroline Morley)This session was a mashup of a variety of planetary topics ranging from solar flares to interiors to habitability.Leslie Rogers kicked off the session by presenting work done in collaboration with her student Ellen Price to constrain the composition of the ultra-short period (4 hours!?!) planet candidate KOI 1843.03 using models of the objects interior. Since its so close to the star, it can only exist without being torn apart if its very dense, which allows them to calculate that it must be iron-rich like Mercury!Next Kevin Thielen, an undergrad at Eckerd College, presented results from a summer project to apply a variable polytrope index to planet models. Tom Barclay then showed models that demonstrate the huge effect that having giant planets in the outer solar system has on the formation of terrestrial planets. He finds that without Jupiter and Saturn, more planets would form (8 instead of 3-4!) and giant impacts (like the moon-forming impact) would be more frequent but less energetic.Aomawa Shields shifted to discuss her 3D GCM models to determine the orbital configurations that would lead to liquid water on the surface of the planet Kepler-62f. She determines the effect of eccentricity, axis tilt (obliquity), and rotation rate on habitability. Edward Guinan brought us closer to home discussing the potential for superflares solar flares up to hundreds of times more

  3. Synthesis and antimicrobial activity of some novel fused heterocyclic 1,2,4-triazolo [3,4-b][1,3,4] thiadiazine derivatives

    Directory of Open Access Journals (Sweden)

    Jagdish K. Sahu

    2014-01-01

    Full Text Available In the present investigation, the synthesis and antimicrobial evaluation of 1,2,4-triazolo [3,4-b][1,3,4] thiadiazine including different pharmacophores are aimed at. In this study, a series of 6-aryl-3- (3,4 -dialkoxyphenyl-7H -[1,2,4]triazolo [3,4-b][1,3,4] thiadiazine (7a-7k was synthesized by condensing 4-amino-5-(3,4-dialkoxyphenyl-4H-[1,2,4]- triazole-3-thiol (6 with various aromatic carboxylic acids in the presence of phenacyl bromides through one-pot reaction. Eleven fused heterocyclic derivatives were successfully synthesized. The structures of these newly synthesized compounds were characterized by IR, 1 H NMR and mass spectroscopic studies. All the synthesized compounds were screened for their antimicrobial evaluation. Some of the compounds exhibited promising antimicrobial activity. From the present study it may be concluded that synthesized compounds are fruitful in terms of their structural novelty and marked biological activities. These compounds could be further modified to develop potential and safer antifungal agents.

  4. 基于Kelvin-Voigt模型的粘弹性波动力学的本征化理论%Eigen Theory of Viscoelastic Dynamics Based on the Kelvin-Voigt Model

    Institute of Scientific and Technical Information of China (English)

    郭少华

    2004-01-01

    利用固体力学本征化理论,研究了具有Kelvin-Voigt粘弹性质的各向异性固体的本征特性,并由此得到了各向异性粘弹性波动力学的广义Stokes方程,展现了波动过程的立体图像.讨论了几类常见各向异性固体的粘弹性波动规律,给出了一些新的结论.

  5. General Rushes Open Days Day I

    CERN Multimedia

    2013-01-01

    General Footage during Open Days 2013 (Day 1 -28/09/2013) Images: Cameramen: Antoine Nouel, Clément Sbaffe, Victor Prunier, David Guerazzi, Basile Manent, Réemi Richarme, Noemi Caraban 00:00:00 00:03:40 Interviews 00:03:40 00:06:54 Beam Instrumentation 00:06:54 00:07:16 Globe 00:07:16 00:10:28 Microcosme 00:10:28 00:12:59 Lectures 00:12:59 00:27:52 Fun with physics 00:27:52 00:28:19 International Village 00:28:19 00:34:18 Fun Zone 00:34:18 00:47:50 ATLAS Surface 00:47:50 00:56:57 ATLAS underground 00:56:57 00:58:53 Detector technologies 00:58:53 01:04:39 CLIC 01:04:39 01:05:56 CMS surface 01:05:56 01:09:32 LINAC 2-3 01:09:32 01:15:29 LINAC 4 01:15:29 01:20:41 Computer Center 01:20:41 01:25:53 Clubs 01:25:53 01:31:49 Beam Instrumentation 01:31:49 01:35:27 Music Festival 01:35:27 01:37:31 SPS 01:37:31 01:46:13 CCC 01:46:13 01:48:24 Safety Trainig Center 01:48:24 01:52:38 COMPASS 01:52:38 01:56:09 EHN1 01:56:09 02:01:42 AMS 02:01:42 02:10:52 Robotics 02:10:52 02:22:48 LHC Point 4 02:22:48 02:23:48 Control Cent...

  6. First Day of Life

    Science.gov (United States)

    ... Know About Zika & Pregnancy The First Day of Life KidsHealth > For Parents > The First Day of Life Print A A A Text Size What's in ... usually begin within the first few hours of life. previous continue Your Feelings Having a baby is ...

  7. Science Challenge Day

    Science.gov (United States)

    Siegel, Deborah

    2013-01-01

    Science fairs can be good motivators, but as extracurricular activities, they leave some students behind. However, by staging a Science Challenge Day at school, educators can involve all students in doing everything from choosing activities to judging projects. This article presents a model for running a successful Science Challenge Day. The…

  8. Father's Day

    Institute of Scientific and Technical Information of China (English)

    北辰

    2004-01-01

    The idea of a special day to honour mothers was first put forward in America in 1907.Tow years later a woman,Mrs.John Bruce Dodd,in the state of Washington,proposed a similar day to honour the head of the family—the father.

  9. A Perfect Day

    Institute of Scientific and Technical Information of China (English)

    DOREMICHELUT

    2004-01-01

    THERE are days where not a thing goes wrong. There's not a glitch. Everything you expect happens, and then more comes along, not because you ask, but because it just does. It's the way life is supposed to be when life is perfect. Memory is what names that day perfect and analyzes it in order to create another, just like it.

  10. April Fools Day

    Institute of Scientific and Technical Information of China (English)

    艾群

    2005-01-01

    April Fools' Day is traditionally a day to play practical jokes on others, send people on fools'things,and fool the unsuspecting(信任的)。No one knows how this holiday began but it was thought to have originated(起源)in France.

  11. Valentine's Day

    Institute of Scientific and Technical Information of China (English)

    顾晓玲

    2009-01-01

    Valentine’s Day,which falls on February14,is one of the most popular festivals of western society and even the whole world.It is a day for lovers,a day when people present chocolates,cards and can-dies to their beloved(心爱的人).

  12. Rainy Day Activities.

    Science.gov (United States)

    Texas Child Care, 1997

    1997-01-01

    Experienced caregivers plan ahead for rainy days. This article describes specific rainy day activities for young children, such as books and crafts to learn about rain (rain in a jar, making a rainbow), simple cooking activities (taffy pull, cinnamon candy tea), and games (mummy wrap, hunt the thimble, rain lotto). (EV)

  13. NO TOBACCO DAY

    CERN Multimedia

    Medical Service

    2002-01-01

    The CERN Medical Service is joining in with the world no tobacco day, which takes place on 31 May 2002. We encourage you to take this opportunity to stop smoking for good. Nurses and Doctors will be present on that day to give out information on methods to stop smoking and to assist you in your efforts.

  14. The climatology, propagation and excitation of ultra-fast Kelvin waves as observed by meteor radar, Aura MLS, TRMM and in the Kyushu-GCM

    Directory of Open Access Journals (Sweden)

    R. N. Davis

    2011-10-01

    Full Text Available Wind measurements from a meteor radar on Ascension Island (8° S, 14° W and simultaneous temperature measurements from the Aura MLS instrument are used to characterise ultra-fast Kelvin waves (UFKW of zonal wavenumber 1 (E1 in the mesosphere and lower thermosphere (MLT in the years 2005–2010. These observations are compared with some predictions of the Kyushu-general circulation model. Good agreement is found between observations of the UFKW in the winds and temperatures, and also with the properties of the waves in the Kyushu-GCM. UFKW are found at periods between 2.5–4.5 days with amplitudes of up to 40 m s−1 in the zonal winds and 6 K in the temperatures. The average vertical wavelength is found to be 44 km. Amplitudes vary with latitude in a Gaussian manner with the profiles centred over the equator. Dissipation of the waves results in monthly-mean eastward accelerations of 0.2–0.9 m s−1 day−1 at heights around 95 km, with 5-day mean peak values of 4 m s−1 day−1. Largest wave amplitudes and variances are observed over Indonesia and central Africa and may be a result of very strong moist convective heating over those regions. Rainfall data from TRMM are used as a proxy for latent-heat release in an investigation of the excitation of these waves. No strong correlation is found between the occurrence of large-amplitude mesospheric UFKW events and either the magnitude of the equatorial rainfall or the amplitudes of E1 signatures in the rainfall time series, indicating that either other sources or the propagation environment are more important in determining the amplitude of UFKW in the MLT. A strong semiannual variation in wave amplitudes is observed. Intraseasonal oscillations (ISOs with periods 25–60 days are evident in the zonal background winds, zonal-mean temperature, UFKW amplitudes, UFKW accelerations and the rainfall rate. This suggests that UFKW play a role in

  15. The climatology, propagation and excitation of ultra-fast Kelvin waves as observed by meteor radar, Aura MLS, TRMM and in the Kyushu-GCM

    Directory of Open Access Journals (Sweden)

    R. N. Davis

    2012-02-01

    Full Text Available Wind measurements from a meteor radar on Ascension Island (8° S, 14° W and simultaneous temperature measurements from the Aura MLS instrument are used to characterise ultra-fast Kelvin waves (UFKW of zonal wavenumber 1 (E1 in the mesosphere and lower thermosphere (MLT in the years 2005–2010. These observations are compared with some predictions of the Kyushu-general circulation model. Good agreement is found between observations of the UFKW in the winds and temperatures, and also with the properties of the waves in the Kyushu-GCM. UFKW are found at periods between 2.5–4.5 days with amplitudes of up to 40 m s−1 in the zonal winds and 6 K in the temperatures. The average vertical wavelength is found to be 44 km. Amplitudes vary with latitude in a Gaussian manner with the maxima centred over the equator. Dissipation of the waves results in monthly-mean eastward accelerations of 0.2–0.9 m s−1 day−1 at heights around 95 km, with 5-day mean peak values of 4 m s−1 day−1. Largest wave amplitudes and variances are observed over Indonesia and central Africa and may be a result of very strong moist convective heating over those regions. Rainfall data from TRMM are used as a proxy for latent-heat release in an investigation of the excitation of these waves. No strong correlation is found between the occurrence of large-amplitude mesospheric UFKW events and either the magnitude of the equatorial rainfall or the amplitudes of E1 signatures in the rainfall time series, indicating that either other sources or the propagation environment are more important in determining the amplitude of UFKW in the MLT. A strong semiannual variation in wave amplitudes is observed. Intraseasonal oscillations (ISOs with periods 25–60 days are evident in the zonal background winds, zonal-mean temperature, UFKW amplitudes, UFKW accelerations and the rainfall rate. This suggests that UFKW play a role in

  16. On the incidence of Kelvin-Helmholtz instability for mass exchange process at the Earth’s magnetopause

    Directory of Open Access Journals (Sweden)

    R. Smets

    Full Text Available Due to the velocity shear imposed by the solar wind flowing around the magnetosphere, the magnetopause flanks are preferred regions for the development of a Kelvin-Helmholtz instability. Since its efficiency for momentum transfer across the magnetopause has already been established, we investigate its efficiency for mass transfer. Using nonresistive magnetohydrodynamic simulations to describe the magnetic field shape in the instability region, we use test-particle calculations to analyse particle dynamics. We show that the magnetopause thickness and the instability wave-length are too large to lead to nonadiabatic motion of thermal electrons from the magnetosphere. On the other hand, the large mass of H+, He+ and O+ ions leads to such nonadiabatic motion and we thus propose the Kelvin-Helmholtz instability as a mechanism for either magnetospheric ion leakage into the magnetosheath or solar wind ion entry in the magnetosphere. Test-particle calculations are performed in a dimensionless way to discuss the case of each type of ion. The crossing rate is of the order of 10%. This rate is anti-correlated with shear velocity and instability wavelength. It increases with the magnetic shear. The crossing regions at the magnetopause are narrow and localized in the vicinity of the instability wave front. As a Kelvin-Helmholtz instability allows for mass transfer through the magnetopause without any resistivity, we propose it as an alternate process to reconnection for mass transfer through magnetic boundaries.

    Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; MHD waves and instabilities – Space plasma physics (numerical simulation studies

  17. Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2011-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

  18. The acute and subchronic effect of 3,4-methylenedioxymethamphetamine on body temperature in rats

    Directory of Open Access Journals (Sweden)

    Simić Ivan

    2009-01-01

    Full Text Available Introduction. The consumption of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy is known to cause severe hyperthermia in humans. This is of extreme importance since ecstasy is often consumed at 'rave' parties, where dancing takes place in a warm environment, which may exacerbate the effect of MDMA on thermoregulation. The present study was performed in order to evaluate the effects of single and repeated administration of MDMA on body temperature in Wistar rats. Material and methods. The study included 72 male Wistar rats, housed in groups of four in cages at a room temperature of 222oC. They were divided in two groups. The rats in the first group were treated with oral solution of MDMA (5 mg/kg, 10 mg/kg, 20 mg/kg, 40 mg/kg and their temperature was measured hourly until 8th hour. The rats in the second group were treated with oral solution of MDMA (5 mg/kg, 10 mg/kg, 20 mg/kg every day during 15 days and their temperature was measured daily at 0th, 1st, 3rd, 5th and 8th hour. Temperature was measured by inserting a thermocouple probe 2,5 cm into the rectum. Results. Both groups showed dose dependent increase of body temperature, determined by rectal temperature measurements. The magnitude of hyperthemic response caused by subchronic administration of MDMA was markedly diminished during the experiment. Conclusion. The hyperthermic effect of MDMA was dose-dependent. The magnitude of the hyperthermic response was markedly diminished in subchronic administration.

  19. Effects of 3,4-methylenedioxymethamphetamine administration on retinal physiology in the rat.

    Directory of Open Access Journals (Sweden)

    João Martins

    Full Text Available 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy is known to produce euphoric states, but may also cause adverse consequences in humans, such as hyperthermia and neurocognitive deficits. Although MDMA consumption has been associated with visual problems, the effects of this recreational drug in retinal physiology have not been addressed hitherto. In this work, we evaluated the effect of a single MDMA administration in the rat electroretinogram (ERG. Wistar rats were administered MDMA (15 mg/kg or saline and ERGs were recorded before (Baseline ERG, and 3 h, 24 h, and 7 days after treatment. A high temperature (HT saline-treated control group was also included. Overall, significantly augmented and shorter latency ERG responses were found in MDMA and HT groups 3 h after treatment when compared to Baseline. Twenty-four hours after treatment some of the alterations found at 3 h, mainly characterized by shorter latency, tended to return to Baseline values. However, MDMA-treated animals still presented increased scotopic a-wave and b-wave amplitudes compared to Baseline ERGs, which were independent of temperature elevation though the latter might underlie the acute ERG alterations observed 3 h after MDMA administration. Seven days after MDMA administration recovery from these effects had occurred. The effects seem to stem from specific changes observed at the a-wave level, which indicates that MDMA affects subacutely (at 24 h retinal physiology at the outer retinal (photoreceptor/bipolar layers. In conclusion, we have found direct evidence that MDMA causes subacute enhancement of the outer retinal responses (most prominent in the a-wave, though ERG alterations resume within one week. These changes in photoreceptor/bipolar cell physiology may have implications for the understanding of the subacute visual manifestations induced by MDMA in humans.

  20. Evaluation of Bcl-2 Family Gene Expression in Hippocampus of 3, 4-methylenedioxymethamphetamine Treated Rats

    Directory of Open Access Journals (Sweden)

    Hamed Hashemi-Nasl

    2012-01-01

    Full Text Available Objective: 3,4-methylenedioxymethamphetamine (MDMA is an illicit, recreational drugthat causes cellular death and neurotoxicity. This study evaluates the effects of differentdoses of MDMA on the expression of apoptosis–related proteins and genes in the hippocampusof adult rats.Materials and Methods: In this expremental study,a total of 20 male Sprague Dawley rats(200-250 g were treated with MDMA (0, 5, 10, 20 mg/kg i.p. twice daily for 7 days. Sevendays after the last administration of MDMA, the rats were killed. Bax and Bcl-2 genesin addition to protein expressions were detected by western blot and reverse transcriptionpolymerasechain reaction (RT-PCR.Results were analyzed using one-way ANOVA andp≤0.05 was considered statistically significant.Results: Our results showed that MDMA caused dose dependent up-regulation of Baxand down-regulation of Bcl-2 in the hippocampus. There was a significant alteration inbcl-2 and bax genes density.Conclusion: Changes in apoptosis-related proteins and respective genes relating to Baxand Bcl-2 might be involved in the molecular mechanism of MDMA-induced apoptosis.

  1. Kelvin probe force microscopy study on operating In-Sn-O-channel ferroelectric-gate thin-film transistors

    International Nuclear Information System (INIS)

    Surface potentials of an operating In-Sn-O channel ferroelectric-gate transistor (FGT) were mapped by Kelvin probe force microscopy. We clearly observed a gradual transition within the channel from linear potential profile to superlinear ones when drain voltage approaches and overcomes gate voltage, which is related to the physics of electronic transport under field-effect doping. The dependence of field-effect mobility on gate-bias and lateral field, as well as the effect of source/drain electrode materials on transport properties, was also elucidated. This study provides useful information for optimizing the FGT performance and for understanding its underlying physics

  2. Kelvin probe force microscopy study on operating In-Sn-O-channel ferroelectric-gate thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tue, P. T., E-mail: phan-tt@jaist.ac.jp; Tokumitsu, E.; Shimoda, T. [ERATO, Shimoda Nano-Liquid Process Project, Japan Science and Technology Agency, 2-13 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 2-13 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Miyasako, T. [Yokkaichi Research Center, JSR Corporation, Yokkaichi 510-8552 (Japan)

    2014-03-14

    Surface potentials of an operating In-Sn-O channel ferroelectric-gate transistor (FGT) were mapped by Kelvin probe force microscopy. We clearly observed a gradual transition within the channel from linear potential profile to superlinear ones when drain voltage approaches and overcomes gate voltage, which is related to the physics of electronic transport under field-effect doping. The dependence of field-effect mobility on gate-bias and lateral field, as well as the effect of source/drain electrode materials on transport properties, was also elucidated. This study provides useful information for optimizing the FGT performance and for understanding its underlying physics.

  3. Décomposition de Kelvin et concept de contraintes effectives multiples pour les matériaux anisotropes

    Science.gov (United States)

    Desmorat, Rodrigue

    2009-11-01

    The effective stress concept, now classical in continuum damage mechanics, is generalized to the case of an initial anisotropy. In order to be used for both damage-elasticity and damage-(visco-)plasticity coupling, the effective stress should not depend on the elastic properties. Kelvin decomposition of the elasticity tensor allows to define such a stress for isotropic and cubic symmetries. For other material symmetries, the concept of multiple effective stresses is proposed. To cite this article: R. Desmorat, C. R. Mecanique 337 (2009).

  4. Influence of Oxygen Partial Pressure on the Fermi Level of ZnO Films Investigated by Kelvin Probe Force Microscopy

    International Nuclear Information System (INIS)

    The influence of oxygen partial pressure on the Fermi level of ZnO films prepared by pulsed laser deposition is investigated. The contact potential difference of the ZnO films fabricated under various oxygen partial pressures is studied systematically using Kelvin probe force microscopy. The Fermi level shifted by 0.35 eV as oxygen partial pressure increased. This indicates a significant change in the electronic structure and energy balance in ZnO films. This fact provides a consistent explanation that the changes in carrier concentration, resistivity and mobility of ZnO films are attributed to oxygen vacancy induced shift of the Fermi level

  5. Influence of Oxygen Partial Pressure on the Fermi Level of ZnO Films Investigated by Kelvin Probe Force Microscopy

    Science.gov (United States)

    Su, Ting; Zhang, Hai-Feng

    2012-12-01

    The influence of oxygen partial pressure on the Fermi level of ZnO films prepared by pulsed laser deposition is investigated. The contact potential difference of the ZnO films fabricated under various oxygen partial pressures is studied systematically using Kelvin probe force microscopy. The Fermi level shifted by 0.35 eV as oxygen partial pressure increased. This indicates a significant change in the electronic structure and energy balance in ZnO films. This fact provides a consistent explanation that the changes in carrier concentration, resistivity and mobility of ZnO films are attributed to oxygen vacancy induced shift of the Fermi level.

  6. Light yield of an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin

    OpenAIRE

    Liu, Jing; Yamashita, Masaki; Soma, Arun Kumar

    2016-01-01

    A light yield of 20.4 $\\pm$ 0.8 photoelectrons/keV was achieved with an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin. This is by far the largest yield in the world achieved with CsI crystals. An energy threshold that is several times lower than the current dark matter experiments utilizing CsI(Tl) crystals may be achievable using this technique. Together with novel CsI crystal purification methods, the technique may be used to improve the sensitivities of dark m...

  7. Te inclusion-induced electrical field perturbation in CdZnTe single crystals revealed by Kelvin probe force microscopy.

    Science.gov (United States)

    Gu, Yaxu; Jie, Wanqi; Li, Linglong; Xu, Yadong; Yang, Yaodong; Ren, Jie; Zha, Gangqiang; Wang, Tao; Xu, Lingyan; He, Yihui; Xi, Shouzhi

    2016-09-01

    To understand the effects of tellurium (Te) inclusions on the device performance of CdZnTe radiation detectors, the perturbation of the electrical field in and around Te inclusions was studied in CdZnTe single crystals via Kelvin probe force microscopy (KPFM). Te inclusions were proved to act as lower potential centers with respect to surrounding CdZnTe matrix. Based on the KPFM results, the energy band diagram at the Te/CdZnTe interface was established, and the bias-dependent effects of Te inclusion on carrier transportation is discussed. PMID:27376976

  8. Role of the Kelvin-Helmholtz instability in the evolution of magnetized relativistic sheared plasma flows.

    Science.gov (United States)

    Hamlin, Nathaniel D; Newman, William I

    2013-04-01

    We explore, via analytical and numerical methods, the Kelvin-Helmholtz (KH) instability in relativistic magnetized plasmas, with applications to astrophysical jets. We solve the single-fluid relativistic magnetohydrodynamic (RMHD) equations in conservative form using a scheme which is fourth order in space and time. To recover the primitive RMHD variables, we use a highly accurate, rapidly convergent algorithm which improves upon such schemes as the Newton-Raphson method. Although the exact RMHD equations are marginally stable, numerical discretization renders them unstable. We include numerical viscosity to restore numerical stability. In relativistic flows, diffusion can lead to a mathematical anomaly associated with frame transformations. However, in our KH studies, we remain in the rest frame of the system, and therefore do not encounter this anomaly. We use a two-dimensional slab geometry with periodic boundary conditions in both directions. The initial unperturbed velocity peaks along the central axis and vanishes asymptotically at the transverse boundaries. Remaining unperturbed quantities are uniform, with a flow-aligned unperturbed magnetic field. The early evolution in the nonlinear regime corresponds to the formation of counter-rotating vortices, connected by filaments, which persist in the absence of a magnetic field. A magnetic field inhibits the vortices through a series of stages, namely, field amplification, vortex disruption, turbulent breakdown, and an approach to a flow-aligned equilibrium configuration. Similar stages have been discussed in MHD literature. We examine how and to what extent these stages manifest in RMHD for a set of representative field strengths. To characterize field strength, we define a relativistic extension of the Alfvénic Mach number M(A). We observe close complementarity between flow and magnetic field behavior. Weaker fields exhibit more vortex rotation, magnetic reconnection, jet broadening, and intermediate turbulence

  9. Microscale dynamics within Kelvin-Helmholtz waves: A probe of localized reconnection occurrence

    Science.gov (United States)

    Walsh, A. P.; Varsani, A.; Owen, C. J.; Fazakerley, A. N.; Rae, J.; Forsyth, C.; Andre, M.; Dandouras, I. S.; Carr, C.

    2014-12-01

    During periods of northward IMF, an absence of low latitude reconnection at the magnetopause is expected. However, this gives rise to questions as to how the low latitude boundary layer (LLBL) can be populated with magnetosheath-like plasma under northward IMF conditions. Multi-spacecraft observations have shown the existence of Ultra-Low Frequency waves at the magnetopause that are thought to be results of the Kelvin-Helmholtz (K-H) instability (Miura, 1982). These K-H waves can grow into non-linear waves and form rolled-up vortices. It has been postulated that magnetic reconnection within these vortices may be responsible for the transfer of solar wind plasma into the magnetosphere (e.g. La Belle-Hamer et al., 1988; Nykyri and Otto, 2001; Hasegawa et al., 2004; Bavassano Cattaneo et al., 2010). Thus, high temporal resolution plasma observations sufficient to resolve reconnection signatures inside K-H vortices (e.g.) are key to understanding how reconnection bursts contribute to coupling of the magnetosheath plasma with magnetosphere. We study an event in Dec 2006, in which Cluster encountered on-going K-H waves as the spacecraft were inbound and crossed the Earth's dusk flank magnetopause through the LLBL. During this event, the spacecraft were operating in burst mode, and the magnetic field remained closely aligned with the spacecraft spin axis. Thus we have used the 3D particle data to reconstruct near-full pitch angle distribution of electrons and ions at sub-spin resolution (0.125s c.f., 4s spin resolution). These observations, up to 32 times faster than normal mode data, provided new insight into particle dynamics during the outbound movements of Cluster across the magnetopause. We present observations of regions where boundary plasma was traveling faster than bulk magnetosheath velocity, which is a plasma signature indicative of rolled up K-H vortices. Within these vortices, we show evidence of reconnection, which consist of D-shape accelerated ion

  10. Possible Signatures Of Kelvin-Helmholtz Waves On The Dusk Flank Of The Kronian Magnetopause

    Science.gov (United States)

    Cutler, Jack; Masters, Adam; Dougherty, Michele; Lucek, Elizabeth; Kanani, Sheila

    2010-05-01

    A comprehensive survey of crossings of both Saturn's magnetopause and bow shock on the dusk side between January 2007 and December 2007 was compiled, using data from the Cassini fluxgate magnetometer and the Cassini electron spectrometer. Bow shock and magnetopause crossings were determined by the criteria discussed in Masters et al., 2008 and Masters et al., 2009 [1] respectively. 396 magnetopause crossings and 165 bow shock crossings were identified with large spatial variation; the high temporal frequency of crossings combined with the large radial variation was indicative of highly dynamic boundaries. A set of magnetopause crossings occurring near the nose of the magnetopause on the 30th June and 1st July 2007 were then analysed using minimum variance analysis (MVA) of the magnetic field vectors over the crossing interval to determine the direction of the boundary normal at each crossing. Using MVA analysis again to calculate the maximum variance direction of the magnetopause normals, I found a clear preferred direction of variance of the normals. The normals were found to deviate by an average of 30° about the average normal direction in the plane of maximum variance, but only by 12° in the perpendicular plane. The observed oscillation of dawn side crossing normals (Masters et al., 2009) was not present throughout the whole dusk set, but was present for subsets, which is suggestive of wave activity. Considering the orientation between the magnetospheric magnetic field and the direction of maximum variance of the normals, the Kelvin-Helmholtz (K-H) instability is the likely driving force of these boundary perturbations. Current work involves analyzing two further magnetopause crossing sets, one further dusk-ward and one closer to noon (SLT), to identify whether K-H waves are also present at these locations. [1] Masters, A.; McAndrews, H. J.; Steinberg, J. T.; Thomsen, M. F.; Arridge, C. S.; Dougherty, M. K.; Billingham, L.; Schwartz, S. J.; Sergis, N

  11. That Rainy Day

    Institute of Scientific and Technical Information of China (English)

    吴洪

    2000-01-01

    Many things have happened since I began to remember things. Pleasant or sad, they've left some impressions on my mind. Some are fading from my memory while others are and will be remembered for ever as if they had happened yesterday, and the scene on that rainy day is just one of such memories. It was on July 7th, 1990, the first day of the 3-day college entrance examination. I got up early that morning, feeling so excited and nervous that I lost all my appetite. What's worse, it began raining, adding vexat...

  12. 低频周期荷载下广义Kelvin-Voigt模型特性研究%A study of behaviors of generalized Kelvin-Voigt model under low frequency cyclic load

    Institute of Scientific and Technical Information of China (English)

    黄明; 刘新荣; 祝云华; 钟祖良

    2009-01-01

    不考虑低频简谐荷载作用下材料的疲劳破坏,并假定周期应力幅值恒定,从材料流变特性的宏观角度建立了广义Kelvin-Voigt体的正弦加载蠕变模型,并对模型特性进行分析.结果表明:与相同静载应力下(与动荷载应力最大值相等)广义Kelvin-Voigt体蠕变模型相比,蠕变变化规律相似,但动载初始蠕变阶段和稳定蠕变阶段的变形值小于静蠕变,且初始蠕变段经历时间比静蠕变短,此结论与相关文献试验结果相似;动载周期越大,则初始蠕变段经历时间越长,蠕变长期应变值越大.

  13. Ineffectiveness of 3,4-diaminopyridine as a therapy for type C botulism.

    Science.gov (United States)

    Siegel, L.S.; Price, J.I.

    1987-01-01

    Clostridium botulinum neurotoxins inhibit acetylcholine release at neuromuscular junctions. Agents stimulating neurotransmitter efflux, such as 3,4-diaminopyridine (3,4-DAP), could be useful for botulism therapy. Treatment with 3,4-DAP (8 mg/kg hourly, beginning 3 hr after toxin injection) failed to increase the survival times of mice receiving 10, 20 or 40 LD50 type C, but did prolong the survival of those receiving 20 LD50 type A. This difference in 3,4-DAP efficacy may reflect variations in the molecular mechanism of action of types A and C botulinum neurotoxins.

  14. Bad Air Day

    Science.gov (United States)

    ... link, please review our exit disclaimer . Subscribe Bad Air Day Air Quality and Your Health In many parts of the country, summer has the worst air quality of any season. When the forecast says ...

  15. Mother’s Day

    Institute of Scientific and Technical Information of China (English)

    李瑞海

    2011-01-01

    难度指数:★★★☆☆词数:408建议阅读时间:5分钟Mother’s Day is a time of commemoration(纪念)and celebration for mothers.It is a time of breakfastin bed,family gatherings,and crayons scribbled"ILove You".The earliest Mother’s Day celebrations can betraced back to the spring celebrations of ancient

  16. Synthesis of 1-Substituted Carbazolyl-1,2,3,4-tetrahydro- and Carbazolyl-3,4-dihydro-β-carboline Analogs as Potential Antitumor Agents

    Directory of Open Access Journals (Sweden)

    Ji-Wang Chern

    2011-02-01

    Full Text Available A series of 1-substituted carbazolyl-1,2,3,4-tetrahydro- and carbazolyl-3,4-dihydro-b-carboline analogs have been synthesized and evaluated for antitumor activity against human tumor cells including KB, DLD, NCI-H661, Hepa, and HepG2/A2 cell lines. Among these, compounds 2, 6, 7, and 9 exhibited the most potent and selective activity against the tested tumor cells. As for inhibition of topoisomerase II, compounds 1–14 and 18 showed better activity than etoposide. Among them, compounds 3, 4, 7, 9, and 10 exhibited potent activity. The structure and activity relationship (SAR study revealed correlation between carbon numbers of the side chain and biological activities. The molecular complex with DNA for compound 2 was proposed.

  17. An extended day program

    Directory of Open Access Journals (Sweden)

    Ševkušić-Mandić Slavica G.

    2002-01-01

    Full Text Available The paper presents the results of a pilot project evaluation, carried out as an action investigation whose aim was to provide a better quality extended day for primary school students. The project included the training of teachers involved in extended day program, designing of special activities performed by teachers with children once a week as well as changes and equipping of premises where children stay. The aims of the program were conception and performance of activities in a less formal way than during regular instructional days, linking of learning at school and acquired knowledge to everyday experiences, and work on contents contributing to the development of child's interests and creativity. The program was accomplished in a Belgrade primary school during the 2001/2002 academic year, comprising students of 1st and 2nd grades (N=77. The effects of the program were monitored throughout the academic year (observation and teachers' reports on accomplished workshops and at the end of the academic year (teachers and students' opinions of the program, academic achievement and creativity of students attending the extended day program compared with students not attending it. Findings about positive effects of the program on students' broadening of interests and willingness to express themselves creatively, indicate unequivocally that there is a need for developing special extended day programs. The extended day program is an opportunity for school to exert greater educational influence that has yet to be tapped.

  18. Open Day: General Information

    CERN Multimedia

    2004-01-01

    http://www.cern.ch/cern50/ With 50 visit points, including theatre performances, debates and visits to installations that have never before been opened to the public, CERN's 50th anniversary Open Day is set to be a day to remember. Seven hundred volunteers have signed up to help for the day. The Open Day team truly appreciates this wonderful show of support! The Open Day would not be possible without their help. Car parking and Access Cars with a CERN sticker can access all CERN sites as normal. However, to avoid congestion on Meyrin site, we ask you to park in areas that will not be open to the public (see below) and to use the shuttle services wherever possible for your transport during the day. Private cars on the French side of the border without a CERN sticker will be diverted to a car park area in the Prévessin site. There is a shuttle service connecting the Meyrin and Prévessin sites via SM18 every 20 minutes. Private cars on the Swiss side of the border without a CERN sticker will be diverte...

  19. Study on pharmacokinetics of 3,4-divanillyltetrahydrofuran in rats by ultra-fast liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Shan, Chen-xiao; Cui, Xiao-bing; Yu, Sheng; Chai, Chuan; Wen, Hong-mei; Wang, Xin-zhi; Sun, Xue

    2016-01-01

    3,4-Divanillyltetrahydrofuran is the main active ingredient of nettle root which can increase steroid hormones in the bloodstream for many of bodybuilders. To better understand its pharmacological activities, we need to determine its pharmacokinetic profiles. In this study, a rapid and sensitive ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed for the determination of 3,4-divanillyltetrahydrofuran in the plasma of rats. Chromatographic separation was performed on a C18 column at 40°C, with a gradient elution consisting of methanol and water containing 0.3% (v/v) formic acid at a flow rate of 0.8mL/min. The detection was performed using an electrospray triple-quadrupole MS/MS via positive ion multiple reaction monitoring mode. The lower limits-of-quantification determined were 0.5ng/mL. The intra- and inter-day precision (RSD%) was found to be within 15% and the accuracy (RE%) ranged from -4.0% to 7.0%. This simple yet sensitive method was fully validated and could be successfully applied to the study on pharmacokinetics of 3, 4-divanillyltetrahydrofuran. PMID:26680326

  20. 3,4-DGE is cytotoxic and decreases HSP27/HSPB1 in podocytes.

    Science.gov (United States)

    Sanchez-Niño, Maria Dolores; Poveda, Jonay; Sanz, Ana Belen; Carrasco, Susana; Ruiz-Ortega, Marta; Selgas, Rafael; Egido, Jesus; Ortiz, Alberto

    2014-03-01

    Hyperglycemia is the key driver of diabetic complications and increased concentrations of glucose degradation products. The study of peritoneal dialysis solution biocompatibility has highlighted the adverse biological effects of glucose degradation products. Recently, 3,4-dideoxyglucosone-3-ene (3,4-DGE) was identified as the most toxic glucose degradation product in peritoneal dialysis fluids. In addition, 3,4-DGE is present in high-fructose corn syrup, and its precursor 3-deoxyglucosone is increased in diabetes. The role of 3,4-DGE in glomerular injury had not been addressed. We studied the effects of 3,4-DGE on cultured human podocytes and in vivo in mice. 3,4-DGE induced apoptosis in podocytes in a dose- and time-dependent manner. 3,4-DGE promoted the release of cytochrome c from mitochondria and activation of caspase-3. While high glucose concentrations increased the levels of the podocyte intracellular antiapoptotic protein HSP27/HSPB1, 3,4-DGE decreased the expression of podocyte HSP27/HSPB1. Apoptosis induced by 3,4-DGE was caspase-dependent and could be prevented by the broad-spectrum caspase inhibitor zVAD-fmk. Antagonism of Bax by a Ku-70-derived peptide also prevented apoptosis. Intravenous administration of 3,4-DGE to healthy mice resulted in a decreased expression of HSP27/HSPB1 and caspase-3 activation in whole kidney and in podocytes in vivo. In conclusion, 3,4-DGE induces apoptotic cell death in cultured human podocytes, suggesting a potential role in glomerular injury resulting from metabolic disorders. PMID:24337777

  1. Probing the energy levels of perovskite solar cells via Kelvin probe and UV ambient pressure photoemission spectroscopy.

    Science.gov (United States)

    Harwell, J R; Baikie, T K; Baikie, I D; Payne, J L; Ni, C; Irvine, J T S; Turnbull, G A; Samuel, I D W

    2016-07-20

    The field of organo-lead halide perovskite solar cells has been rapidly growing since their discovery in 2009. State of the art devices are now achieving efficiencies comparable to much older technologies like silicon, while utilising simple manufacturing processes and starting materials. A key parameter to consider when optimising solar cell devices or when designing new materials is the position and effects of the energy levels in the materials. We present here a comprehensive study of the energy levels present in a common structure of perovskite solar cell using an advanced macroscopic Kelvin probe and UV air photoemission setup. By constructing a detailed map of the energy levels in the system we are able to predict the importance of each layer to the open circuit voltage of the solar cell, which we then back up through measurements of the surface photovoltage of the cell under white illumination. Our results demonstrate the effectiveness of air photoemission and Kelvin probe contact potential difference measurements as a method of identifying the factors contributing to the open circuit voltage in a solar cell, as well as being an excellent way of probing the physics of new materials.

  2. Probing the energy levels of perovskite solar cells via Kelvin probe and UV ambient pressure photoemission spectroscopy.

    Science.gov (United States)

    Harwell, J R; Baikie, T K; Baikie, I D; Payne, J L; Ni, C; Irvine, J T S; Turnbull, G A; Samuel, I D W

    2016-07-20

    The field of organo-lead halide perovskite solar cells has been rapidly growing since their discovery in 2009. State of the art devices are now achieving efficiencies comparable to much older technologies like silicon, while utilising simple manufacturing processes and starting materials. A key parameter to consider when optimising solar cell devices or when designing new materials is the position and effects of the energy levels in the materials. We present here a comprehensive study of the energy levels present in a common structure of perovskite solar cell using an advanced macroscopic Kelvin probe and UV air photoemission setup. By constructing a detailed map of the energy levels in the system we are able to predict the importance of each layer to the open circuit voltage of the solar cell, which we then back up through measurements of the surface photovoltage of the cell under white illumination. Our results demonstrate the effectiveness of air photoemission and Kelvin probe contact potential difference measurements as a method of identifying the factors contributing to the open circuit voltage in a solar cell, as well as being an excellent way of probing the physics of new materials. PMID:27384817

  3. 4th Optimization Day

    CERN Document Server

    Eberhard, Andrew; Ralph, Daniel; Glover, Barney M

    1999-01-01

    Although the monograph Progress in Optimization I: Contributions from Aus­ tralasia grew from the idea of publishing a proceedings of the Fourth Optimiza­ tion Day, held in July 1997 at the Royal Melbourne Institute of Technology, the focus soon changed to a refereed volume in optimization. The intention is to publish a similar book annually, following each Optimization Day. The idea of having an annual Optimization Day was conceived by Barney Glover; the first of these Optimization Days was held in 1994 at the University of Ballarat. Barney hoped that such a yearly event would bring together the many, but widely dispersed, researchers in Australia who were publishing in optimization and related areas such as control. The first Optimization Day event was followed by similar conferences at The University of New South Wales (1995), The University of Melbourne (1996), the Royal Melbourne Institute of Technology (1997), and The University of Western Australia (1998). The 1999 conference will return to Ballarat ...

  4. Synthesis and thermolysis of oxo chloro-2-ethyl-1.3.4-thiadiazole rhenium complex

    International Nuclear Information System (INIS)

    Present article is devoted to synthesis and thermolysis of oxo chloro-2-ethyl-1.3.4-thiadiazole rhenium complex. The synthesis method of oxo chloro-2-ethyl-1.3.4-thiadiazole rhenium complex is elaborated. The kinetics of its thermolysis process is studied. The thermodynamic functions of thermolysis process are evaluated.

  5. Dissecting Oct3/4-regulated gene networks in embryonic stem cells by expression profiling.

    Directory of Open Access Journals (Sweden)

    Ryo Matoba

    Full Text Available POU transcription factor Pou5f1 (Oct3/4 is required to maintain ES cells in an undifferentiated state. Here we show that global expression profiling of Oct3/4-manipulated ES cells delineates the downstream target genes of Oct3/4. Combined with data from genome-wide chromatin-immunoprecipitation (ChIP assays, this analysis identifies not only primary downstream targets of Oct3/4, but also secondary or tertiary targets. Furthermore, the analysis also reveals that downstream target genes are regulated either positively or negatively by Oct3/4. Identification of a group of genes that show both activation and repression depending on Oct3/4 expression levels provides a possible mechanism for the requirement of appropriate Oct3/4 expression to maintain undifferentiated ES cells. As a proof-of-principle study, one of the downstream genes, Tcl1, has been analyzed in detail. We show that Oct3/4 binds to the promoter region of Tcl1 and activates its transcription. We also show that Tcl1 is involved in the regulation of proliferation, but not differentiation, in ES cells. These findings suggest that the global expression profiling of gene-manipulated ES cells can help to delineate the structure and dynamics of gene regulatory networks.

  6. 45 CFR 3.4 - False reports and reports of injury or damage.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false False reports and reports of injury or damage. 3.4 Section 3.4 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF... reports of injury or damage. A person may not knowingly give any false or fictitious report concerning...

  7. Prevalence of use study for amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), and 3,4-methylenedioxy-ethylamphetamine (MDEA) in military entrance processing stations (MEPS) specimens.

    Science.gov (United States)

    Klette, Kevin L; Kettle, Aaron R; Jamerson, Matthew H

    2006-06-01

    The Roche Abuscreen Onlinetrade mark Amphetamine immunoassay (IA), modified to include sodium periodate, and the Microgenics DRI Ecstasy IA were used to determine the prevalence of amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) in urine specimens from applicants seeking to join the United States Armed Forces. Over a 4-month period, a total of 85,658 specimens were IA screened using the Department of Defense 500 ng/mL administrative cutoff level for AMP and MDMA. All presumptively positive specimens were confirmed using a solid-phase extraction procedure coupled with simultaneous analysis of AMP, MAMP, MDA, MDMA, and MDEA by fast gas chromatography-mass spectrometry using the same cutoff levels as the IA. The Roche Online Amphetamine IA identified 216 specimens as presumptively positive; of these, 70 specimens confirmed positive for AMP and 87 specimens confirmed positive for AMP and/or MAMP, resulting in a confirmation rate of 73%. The Microgenics DRI Ecstasy IA identified eight specimens as presumptively positive; of these, five specimens confirmed positive for MDMA and/or MDA, resulting in a confirmation rate of 63%. The total use prevalence for AMP, MAMP, MDA, MDMA, and/or MDEA in military entrance processing stations specimens over the testing period was determined to be 0.19%.

  8. Synthesis and anti-inflammatory activity of 1-acylaminoalkyl-3,4-dialkoxybenzene derivatives.

    Science.gov (United States)

    Labanauskas, L; Brukstus, A; Udrenaite, E; Bucinskaite, V; Susvilo, I; Urbelis, G

    2005-03-01

    New 1-acylaminoalkyl-3,4-dialkoxybenzene derivatives 17-31 were synthesized by the acylation of amines 9-16 with acyl chlorides. Amines 9-16 were obtained from aryl ketones 1-8. Aryl ketones 1-8 were synthesized by the acylation of corresponding aromatic compounds. As it was preliminary predicted by PASS (Prediction of Activity Spectra for Substance) program, all 1-acylaminoalkyl-3,4-dimethoxy- and 3,4-diethoxybenzene derivatives possess anti-inflammatory activity. Activity of compounds 18, 19, 21, 24, 26, 27, 28, 29 was similar to that of acetylsalicylic acid or ibuprofen however their acute toxicity was less than that of mentioned anti-inflammatory drugs. A series of 1-acylaminoalkyl-3,4-dimethoxybenzene, 1-acylaminoalkyl-3,4-diethoxybenzene and 6-acylaminoalkyl-2,3-dihydro-1,4-benzodioxine derivatives have been synthesized. These compounds possess moderate or strong anti-inflammatory activity and low toxicity.

  9. Synthesis and Properties of N, N'-Bis (difuroxano [3,4-b: 3',4'-d]phenyl)oxalic Amide

    Institute of Scientific and Technical Information of China (English)

    WANG,Jian-Long; L(U),Lian-Ying; OU,Yu-Xiang

    2008-01-01

    N,N'-Bis(difuroxano[3,4-b:3',4'-d]phenyl)oxalic amide was synthesized via acylation, nitration, azidation, and pyrolysis-denitrogenation from the starting materials of oxalyl chloride and 3,5-dichloroaniline, under mild reaction conditions, with the yields of 81.0%, 82.0%, 86.0% and 81.7% respectively. The title compound and its precursors were characterized by 1H NMR, IR, MS, and elemental analysis. The title compound has a density of 1.92 g·cm-3 by a suspension method, a standard formation enthalpy of 979 kJ·mol 1 calculated by Gaussian programs, a detonation velocity of 8.17 km·s-1, and a detonation pressure of 31 GPa obtained by Kamlet Equation. The thermal decomposition reactions of the title compound at different heating rates were tested by differential scanning calorimetry (DSC). The kinetics parameters of the pyrolysis of the compound were calculated by Kissinger's method.The values of apparent activation energy (Ea) and pre-exponential constant (A) were 226.7 kJ·mol-1 and 1023.17 s-1 respectively. It was presupposed that N,N'-bis(difuroxano[3,4-b:3',4'-d]phenyl)oxalic amide would be a promising high energetic explosive with low sensitivity.

  10. My Favorite Day

    Institute of Scientific and Technical Information of China (English)

    李峰

    2008-01-01

    It’s Friday, November 14th. I’m happy today. In1 8 o’clock I have Chinese. I like it because it’s fun. Then I have math and art. In2 this day I can have P.E. in the afternoon. That’s my favorite subject. I play football and basketball. Then I have a two-days3 holiday. At 6 o’clock p.m. I can swimming4 for an hour. In5 Friday evening I have a party with my friends.

  11. World Heart Day

    Centers for Disease Control (CDC) Podcasts

    2009-09-01

    For World Heart Day, learn more about what heart-healthy steps you can take in the workplace.  Created: 9/1/2009 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/9/2009.

  12. European Antibiotic Awareness Day

    DEFF Research Database (Denmark)

    Earnshaw, S; Mancarella, G; Mendez, A;

    2014-01-01

    Awareness Day (EAAD) on 18 November as platform to support national campaigns across Europe. This article provides an overview of EAAD tools, materials, and activities developed during the first five years. It shows that EAAD has been successful due to good cooperation between ECDC and national institutions...

  13. April Fool's Day

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ While popular in the U.S., the April Fool's Day tradition is even more popular in European countries, such as France and Great Britain. Although the roots(起源) of the traditional tricks (恶作剧) are unclear, the French and the British both have claims(声称) on the origin(起源) of the celebration.

  14. My Days in Tibet

    Institute of Scientific and Technical Information of China (English)

    Rosemary; Adang

    1999-01-01

    Early on the morning of July 27, 1999, my travel companion, Moira Fulton.and I (two American women) flew to Lhasa. We had been anticipating this dayfor months, and finally we were headed for a five-day visit on "The Roof of theWorld."

  15. CERN openlab Open Day

    CERN Multimedia

    Purcell, Andrew Robert

    2015-01-01

    The CERN openlab Open Day took place on 10 June, 2015. This was the first in a series of annual events at which research and industrial teams from CERN openlab can present their projects, share achievements, and collect feedback from their user communities.

  16. Scheduling: Seven Period Day

    Science.gov (United States)

    Williamson, Ronald

    2010-01-01

    Driven by stable or declining financial resources many school districts are considering the costs and benefits of a seven-period day. While there is limited evidence that any particular scheduling model has a greater impact on student learning than any other, it is clear that the school schedule is a tool that can significantly impact teacher…

  17. Governing To‐day

    DEFF Research Database (Denmark)

    Turner, Kevin

    Governing To-day denotes a domain of research, and what the thesis undertakes is a theoretical discussion of some questions of method vis-à-vis researching this domain. There are two aspects to the title that enfold one another. Firstly, “governing to-day” signposts that it is to!day that is to b...... of departure in the research and writing of the French philosopher and historian, Michel Foucault. It is primarily within the writings of Foucault that the thesis seeks to find a workaround to the problem thrown forth by the aforementioned questions of method.......Governing To-day denotes a domain of research, and what the thesis undertakes is a theoretical discussion of some questions of method vis-à-vis researching this domain. There are two aspects to the title that enfold one another. Firstly, “governing to-day” signposts that it is to...... in time, in the present!day, in this time that is our own, and so forth, that forms the object of enquiry. Accordingly, “governing to!day” denotes both a government of the present and government in the present. In working through said questions of method, the thesis sketches out an approach that takes...

  18. Fabulous Weather Day

    Science.gov (United States)

    Marshall, Candice; Mogil, H. Michael

    2007-01-01

    Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in…

  19. NATIONAL HEARING DAY

    CERN Multimedia

    2003-01-01

    The 12th of June 2003 Is the French National Hearing Day. The Medical Service invites everyone working at CERN to come and have an ear test at the infirmary. Bld. 57, ground floor, between 9h00 and 16h00 Tel. 73802

  20. National hearing day

    CERN Multimedia

    2003-01-01

    The 12th of June 2003 Is the French National Hearing Day. The Medical Service invites everyone working at CERN to come and have an ear test at the infirmary. Bld. 57, ground floor, between 9h00 and 16h00 Tel. 73802

  1. "A Day Without Immigrants"

    DEFF Research Database (Denmark)

    Heiskanen, Benita

    2009-01-01

    Abstract This article considers the debates surrounding the "Day Without Immigrants" protests organized in major U.S. cities on 1 May 2006, prompted by H.R. 4437, the Border Protection, Anti-Terrorism, and Illegal Immigration Control Act of 2005, from the multiple perspectives of scholars, pundits...

  2. Boronic, diboronic, and α-amino-boronic acids derived from 1-ethynyl-3, 4-dimethoxybenzene

    International Nuclear Information System (INIS)

    This work was undertaken with the intention of synthesizing (α-amino-β-(3, 4-dihydroxyphenyl) ethylboronic acid. Unfortunately, the goal could not be attained since the isolation of the target compound could not be achieved though some information suggested its existence in the final product. The methods of synthesis used in the second half of the attempted preparation are described here (compounds in the first half have been published elsewhere). In this procedure, (β-(3, 4-dimethoxyphenyl)) ethenylboronic acid is esterified and azeotropic distillation is conducted to provide diethyl (β-(3, 4-dimethoxyphenyl)) ethenylboronate. This compound is dissolved in diglyme and diborane gas is introduced. The hydroboration product is then subjected to amination with hydroxylamine-0-sulfonic acid. (β-(3, 4-dimethoxyphenyl)) ethyl-α, α-diboronic acid is obtained from the residue of acetone extraction. The acetone extract is concentrated to a solid caramel, from which (α-borono-β-(3, 4-dimethoxyphenyl)) ethylammonium tetraphenylborate is formed. Conversion from the tetraphenylborate salt to (α-amino-β-(3, 4-dimethoxyphenyl)) ethylboronic acid hydrochloride is attempted by the double decomposition RH BPh4 + CsCl -- RH Cl + CsBPh4. The product is subjected to demethylation and treated with sodium tetraphenylborate to precipitate (α-borono-β-(3, 4-dihydroxyphenyl)) ethylammonium tetraphenylborate. Conversion of this to the target compound is tried by double decomposition. (Nogami, K.)

  3. Analysis of common cause failure in Wolsong 2/3/4 NPPs PSA

    International Nuclear Information System (INIS)

    Wolsong 2/3/4 Nuclear Power Plants (WS 2/3/4 NPPs) are CANDU 6 type Pressurized Heavy Water Reactors (PHWRs) being built in Wolsong site of Korea by Korea Power Electric Corporation (KEPCO). WS 2/3/4 NPPs are designed by Atomic Energy of Canada Ltd. (AECL). AECL performs Probabilistic Safety Assessment (PSA) for these NPPs. In this PSA, however, the effect of Common Cause Failure (CCF) is not analyzed due to the limitation of CANDU reliability data. Since the CCF is regarded as one of the most dominant contributors to the total core damage frequency (CDF) in Pressurized Water Reactor (PWR) PSA. KEPCO and Korea Atomic Energy Research Institute (KAERI) initiated WS 2/3/4 NPPs Level 2 PSA which includes the CCF analysis and detailed HRA. In WS 2/3/4 NPPs Level 2 PSA, the authors reviewed the CCF data used in PWR PSA, and applied these data for WS 2/3/4 NPPs Level 2 PSA. The MGL method is implemented for the CCF analysis of WS 2/3/4 NPPs. The analyzed results show that the effect of CCF is not negligible in CANDU PSA as well as in PWR PSA. So the CCF data of CANDU plants should be collected and incorporated into CANDU PSA

  4. Study on Influence Factors of Seismic Wave Attenuation in Kelvin-Voigt Viscoelastic Media%Kelvin-Voigt黏弹介质地震波衰减影响因素研究

    Institute of Scientific and Technical Information of China (English)

    杨思通; 程久龙; 李守军; 赵为永

    2010-01-01

    应用交错网格有限差分法对Kelvin-Viogt黏弹介质中的地震波传播进行了数值模拟,并在此基础上对介质的波阻抗和震源子波频率对地震波时频域衰减特征的影响进行了研究分析.研究表明,随着波阻抗的降低和震源子波频率的增大,地震纵波振幅衰减加快,地震波高频成分能量快速衰减,低频成分能量衰减相对较弱,主频向低频偏移加快.

  5. THE CHAOTIC MOTIONS OF A KELVIN-VOIGT TYPE CURVED PIPE CONVEYING FLUID WITH ENVIRONMENTAL DAMPING%环境阻尼作用下Kelvin-Voigt型输流曲管的混沌运动

    Institute of Scientific and Technical Information of China (English)

    王琳; 倪樵; 黄玉盈

    2005-01-01

    考虑环境阻尼因素的影响,研究了具有运动约束作用Kelvin-Voigt型输流曲管的混沌运动现象.数值仿真表明,输流曲管系统在某些参数取值时具有混沌运动的可能,管道材料的粘弹性系数和环境阻尼等因素对曲管的动力响应产生较大的影响.这些结论可为工程管道系统的铺设与设计提供参考.

  6. Synthesis and Thermal Behavior of a Fused, Tricyclic 1,2,3,4-Tetrazine Ring System.

    Science.gov (United States)

    Chavez, David E; Bottaro, Jeffery C; Petrie, Mark; Parrish, Damon A

    2015-10-26

    This study presents the synthesis and characterization of a fused, tricyclic 1,2,3,4-tetrazine ring system. The molecule is synthesized in a three-step process from 5,5'-dinitro-bis,1,2,4-triazole via a di-N-amino compound. Oxidation to form the azo-coupled fused tricyclic 1,2,3,4-tetrazine is achieved using tert-butyl hypochlorite as the oxidant. The di-N-amino compound and the desired fused tricyclic 1,2,3,4-triazine display interesting thermal behavior and are predicted to be high-performance energetic materials.

  7. Open Days in 2008

    CERN Multimedia

    Corinne Pralavorio

    CERN will be organising two Open Days in 2008, one for CERN employees and their families on Saturday, 5 April, and another for the general public on Sunday, 6 April. This is the one last chance to see the LHC and its experiments. In addition to the surface facilities, visitors will be able to go underground to see the accelerator and will have acces to the experiment caverns. Exceptionally, most of the points along the ring will be open. We need a large number of volunteers to ensure the success of these two very special days. Full details of the events will be published in the first January edition of the Bulletin. Volunteers will be able to register by completing an electronic form and an information session will be organised.

  8. Computer Security Day

    CERN Multimedia

    CERN Bulletin

    2010-01-01

      Viruses, phishing, malware and cyber-criminals can all threaten your computer and your data, even at CERN! Experts will share their experience with you and offer solutions to keep your computer secure. Thursday, 10 June 2010, 9.30, Council Chamber Make a note in your diary! Presentations in French and English: How do hackers break into your computer? Quels sont les enjeux et conséquences des attaques informatiques contre le CERN ? How so criminals steal your money on the Internet? Comment utiliser votre ordinateur de manière sécurisée ? and a quiz: test your knowledge and win one of the many prizes that will be on offer! For more information and to follow the day's events via a live webcast go to: http://cern.ch/SecDay.  

  9. One Day on Earth

    CERN Multimedia

    2011-01-01

    In collaboration with the CineGlobe Film Festival, the One Day on Earth global film project invites you to share your story of scientific inspiration, scientific endeavors and technological advancement on 11 November 2011 (11.11.11).   Technology in the 21st century continuously inspires us to re-imagine the world. From outer-space to cyberspace, new ideas that we hope will improve the lives of future generations keep us in a state of change. However, these new technologies may alter the nature of our shared existence in ways not yet known. On 11.11.11, we invite you to record the exciting ways that science is a part of your life, together with people around the world who will be documenting their lives on this day of global creation. See www.onedayonearth.org for details on how to participate.

  10. CERN Heart Days

    CERN Multimedia

    2003-01-01

    14 & 15 OCTOBER 2003 The Medical Service and the Fire Brigade invite everyone working at CERN to participate in the above event. INFIRMARY 9 am to 16.30 pm Building 57, ground floor No need to book HEALTHY HEART? Evaluation of personal cardiac risks through the monitoring of: Blood pressure Cholesterol and sugar levels Body Mass Index ... and more Leaflets, information and advice concerning cardiac issues FIRE BRIGADE 9 to 12am - Building 65 Please book (limited to 15 people/day) FIRST AID COURSES What to do in a Cardiac Emergency (3 h. duration) Places are limited and on reservation only (15 people/day). To book, e-mail the Medical Services on: service.medical@cern.ch

  11. CERN Heart Days

    CERN Multimedia

    2003-01-01

    14 & 15 OCTOBER 2003 The Medical Service and the Fire Brigade invite everyone working at CERN to participate in the above event. INFIRMARY 9 am to 16.30 pm Building 57, ground floor no need to book HEALTHY HEART? • Evaluation of personal cardiac risks through the monitoring of: Blood pressure Cholesterol and sugar levels Body Mass Index ... and more • Leaflets, information and advice concerning cardiac issues FIRE BRIGADE 9 to 12 am - Building 65 Please book (limited to 15 people/day) FIRST AID COURSES • What to do in a Cardiac Emergency (3 h. duration) Places are limited and on reservation only (15 people/day). To book, e-mail the Medical Services on: service.medical@cern.ch

  12. National HIV Testing Day

    Centers for Disease Control (CDC) Podcasts

    2011-06-09

    Dr. Kevin A. Fenton, Director of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, discusses National HIV Testing Day, an annual observance which raises awareness of the importance of knowing one's HIV status and encourages at-risk individuals to get an HIV test.  Created: 6/9/2011 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 6/9/2011.

  13. Market day midwives.

    Science.gov (United States)

    1994-06-01

    In August 1994 in Uganda, the Social Marketing for Change (SOMARC) project invited midwives to counsel clients and sell low-dose oral contraceptives (OCs), condoms, and the progestin-only OCs in local markets. They now sell these contraceptives from vendor stalls in busy markets, which allows clients to speak privately with the midwives. The midwives refer clients to their maternity clinics or to hospitals for other contraceptive methods and reproductive/maternal and child health (MCH) services. All Market Day Midwives have taken a 1-month family planning course and a course in quality of customer service. By the end of March 1994, 17 midwives served 22 marketplaces ranging from rural village markets operating once every 2 weeks to very busy, daily city markets. Some markets have 15 permanent stalls, while other midwives move within markets. Market Day Midwives have been able to add more than 1900 women to the list of women using the OC Pilplan. 65% of the new acceptors had not used any OC before Pilplan. 46% of them would be women considered to be high risk if they were to become pregnant (teenagers, women over 35, and women with many children). These midwives have been successful because they operate where the people are and they provide anonymity. Market Day Midwives have also brought in men who seek them out for family planning/sexually transmitted disease prevention services. They have sold more than 1000 Protector condoms. Another benefit of the market day approach is professional growth of the midwives. They often invest their earnings into new equipment and their private maternity clinics. They have learned the significance of advertising and the value of high-quality customer service. They look to expand into other markets and to integrate MCH products (e.g., oral rehydration) into their contraceptive business.

  14. A long day

    OpenAIRE

    Fahy, John

    2014-01-01

    My fieldwork is based in Mayapur, West Bengal where the Hare Krishnas have their international headquarters. Once a week the devotees leave their compound for ‘Food for Life’, distributing food to villagers along the Ganges. The kids often come on the boat across the river to help out. After a long day of kirtan and cooking, these kids take a break on the cart on the way back to the boat.

  15. World AIDS Day 2004

    Institute of Scientific and Technical Information of China (English)

    CynthiaKirk; 刘保行

    2005-01-01

    December first was World AIDS Day. Last year, the campaign (运动;活动) centered on women and girls. They made up almost half of all people infected with the virus HIV that causes AIDS. And H1V was spreading faster among women than men in most areas of the world. These findings (发现) werefrom the yearly report by the United Nations and the World Health Organization, a UN agency

  16. Innovation and Entrepreneurship Day

    OpenAIRE

    Di Meglio, Alberto

    2015-01-01

    Scientific Research is one of the strongest drivers behind innovation, but innovation cannot be fully exploited without providing a fertile ground for ideas to develop and mature. What can be done at CERN to maximize the human and technological assets that naturally gather together to work on the next frontiers of Physics research. The Innovation and Entrepreneurship Day is the first event co-organized by CERN openlab, the CERN KT group, IdeaSquare and Intel, a CERN openla industrial partner,...

  17. 'EU divertor celebration day'

    International Nuclear Information System (INIS)

    The meeting 'EU divertor celebration day' organized on 16 January 2002 at Plansee AG, Reutte, Austria was held on the occasion of the completion of manufacturing activities of a complete set of near full-scale prototypes of divertor components including the vertical target, the dome liner and the cassette body. About 30 participants attended the meeting including Dr. Robert Aymar, ITER Director, representatives from EFDA, CEA, ENEA, IPP and others

  18. Synthesis of 1,3,4-Thiadiazole, 1,3,4-Thiadiazine, 1,3,6-Thiadiazepane and Quinoxaline Derivatives from Symmetrical Dithiobiureas and Thioureidoethylthiourea Derivatives

    Directory of Open Access Journals (Sweden)

    A. Abou-Zied

    2005-08-01

    Full Text Available Reactions of N,N`-disubstituted hydrazinecarbothioamides 8a-c and substituted thioureidoethylthioureas 9a-c with 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil, 10a and 2,3,5,6-tetrabromo-1,4-benzoquinone (bromanil, 10b to form N,N`-disubstituted [1,3,4]thiadiazole-2,5-diamines 11a-c, 6,7-dichloro-3-substituted amino-1H-benzo[1,3,4]- thiadiazine-5,8-diones 12a-c, 2,3,7,8-tetrahalothianthrene-1,4,6,9-tetraones 13a,b, 5,6,8- trihalo-7-oxo-3,7-dihydro-2H-quinoxaline-1-carbothioic acid substituted amides 14a-c, 15a-c and 7-substituted imino-[1,3,6]thiadiazepane-3-thiones 16a-c are reported. Rationales for the observed conversions are presented.

  19. Synthesis of 1,3,4-Thiadiazole, 1,3,4-Thiadiazine, 1,3,6-Thiadiazepane and Quinoxaline Derivatives from Symmetrical Dithiobiureas and Thioureidoethylthiourea Derivatives

    OpenAIRE

    Abou-Zied, A.; K. El-Shaieb; A. Mourad; Hassan, A

    2005-01-01

    Reactions of N,N`-disubstituted hydrazinecarbothioamides 8a-c and substituted thioureidoethylthioureas 9a-c with 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil, 10a) and 2,3,5,6-tetrabromo-1,4-benzoquinone (bromanil, 10b) to form N,N`-disubstituted [1,3,4]thiadiazole-2,5-diamines 11a-c, 6,7-dichloro-3-substituted amino-1H-benzo[1,3,4]- thiadiazine-5,8-diones 12a-c, 2,3,7,8-tetrahalothianthrene-1,4,6,9-tetraones 13a,b, 5,6,8- trihalo-7-oxo-3,7-dihydro-2H-quinoxaline-1-carbothioic acid substit...

  20. Synthesis under Microwave Irradiation and Crystal Structure of 4-(3,4-Methylenedioxylphenyl)-6-methyl- 5-ethoxycaronyl-3,4-dihydropyrimidin-2(H)-one

    Institute of Scientific and Technical Information of China (English)

    TU Shu-Jiang; FANG Fang; JIANG Hong; ZHU Song-Lei; LI Tuan-Jie; ZHANG Xiao-Jing; SHI Da-Qing

    2004-01-01

    The title compound 4-(3,4-methylenedioxylphenyl)-6-methyl-5-ethoxycaronyl-3,4- dihydropyrimidin-2(H)-one (C15H16N2O5) has been synthesized and determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group Pī with a = 7.580(1), b = 7.920(2), c = 13.168(4)(A。),α = 96.44(2),β = 96.71(2), γ = 109.81(2)°, V = 728.8(3) (A。)3, Z = 2, Mr = 304.30, Dc = 1.387 g/cm3, F(000) = 320, μ(MoKα) = 0.105 mm-1 (λ = 0.71073(A。)), R = 0.0446 and wR = 0.1205. In the molecule the pyrimidine ring adopts a boat conformation.

  1. Microwave Induced Synthesis of 3-Aryl-6-( 6-/8-substituted 4-chloroquinoline-3-yl) - s - triazolo [ 3,4- b ] - 1,3,4- thiadiazoles

    Institute of Scientific and Technical Information of China (English)

    QIAO,Ren-Zhong(乔仁忠); HUI,Xin-Ping(惠新平); XU,Peng-Fei(许鹏飞); ZHANG,Zi-Yi(张自义); CHENG,Dong-Liang(程东亮)

    2001-01-01

    The condensation of 4-amino-3-aryl-5-mercapto-1, 2, 4-tria-zoles (1a-f) with 6-/8-substituted 1,4-dihydro-4-oxo-quino-line-3-carboxylic acids (2a-d) in the presence of phosphorus oxychloride on refluxing or under microwave irradiation gave twenty four novel 3-aryl-6-(6-/8-substituted 4-chloroquinoline-3-yl)-s-triazolo[3,4-b]-1,3,4-thiadiazoles (4a-x), Consid-erable increase in the reaction rate has been observed with improved yields under microwave irradiation. The structures of the compounds synthesized were determined by elemental analyses, IR, 1H NMR and MS spectra. Their spectral properties and the reaction mechanism were also discussed. The preliminary biological test showed that some of compounds had moderate antibacterial activities.

  2. [Pd4(μ3-SbMe3)4(SbMe3)4]: A Pd(0) Tetrahedron with μ3-Bridging Trimethylantimony Ligands.

    Science.gov (United States)

    Benjamin, Sophie L; Krämer, Tobias; Levason, William; Light, Mark E; Macgregor, Stuart A; Reid, Gillian

    2016-06-01

    The palladium(II) chlorostibine complex [PdCl2(SbMe2Cl)2]2 has a dimeric structure in the solid state, stabilized by hyper-coordination at the Lewis amphoteric Sb centers. Reaction with 8 equiv of MeLi forms [Pd4(μ3-SbMe3)4(SbMe3)4], whose structure comprises a tetrahedral Pd(0) core with four terminal SbMe3 ligands and four μ3-SbMe3 ligands, one capping each triangular Pd3 face. Density functional theory calculations, supported by energy decomposition analysis and the natural orbitals for chemical valence scheme, highlight significant donor and acceptor orbital contributions to the bonding between both the terminal and the bridging SbMe3 ligands and the Pd4 core.

  3. Electrical conductivity in 3,4,9,10-perylenetetracarboxylic dianhidride (PTCDA): Električna prevodnost v 3,4,9,10 perilendianhidrid tetrakarboksilni kislini (PTCDA):

    OpenAIRE

    Bratina, Gvido; Brownell, John Nimly; Hudej, Robert; Zavrtanik, Marko

    2001-01-01

    The transient photoresponse in 3,4,9,10-perylenetetracarboxylic dianhydride was examined in metal/organic semiconductor/metal heterostructures. Electron-hole pairs are generated within the structure for fields higher than 5 X 10sup4 V/cm as a consequence of the exciton dissociation. The mobility of the electrons perpendicular to the molecular layers increases with the applied electric field and saturates for fields higher than 5 X 10sup4 V/cm.

  4. A map of the large day-night temperature gradient of a super-Earth exoplanet.

    Science.gov (United States)

    Demory, Brice-Olivier; Gillon, Michael; de Wit, Julien; Madhusudhan, Nikku; Bolmont, Emeline; Heng, Kevin; Kataria, Tiffany; Lewis, Nikole; Hu, Renyu; Krick, Jessica; Stamenković, Vlada; Benneke, Björn; Kane, Stephen; Queloz, Didier

    2016-04-14

    Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres, but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths--exoplanets with masses of one to ten times that of Earth--have so far revealed only featureless spectra. Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e (refs 4, 5) revealing highly asymmetric dayside thermal emission and a strong day-night temperature contrast. Dedicated space-based monitoring of the planet in the infrared revealed a modulation of the thermal flux as 55 Cancri e revolves around its star in a tidally locked configuration. These observations reveal a hot spot that is located 41 ± 12 degrees east of the substellar point (the point at which incident light from the star is perpendicular to the surface of the planet). From the orbital phase curve, we also constrain the nightside brightness temperature of the planet to 1,380 ± 400 kelvin and the temperature of the warmest hemisphere (centred on the hot spot) to be about 1,300 kelvin hotter (2,700 ± 270 kelvin) at a wavelength of 4.5 micrometres, which indicates inefficient heat redistribution from the dayside to the nightside. Our observations are consistent with either an optically thick atmosphere with heat recirculation confined to the planetary dayside, or a planet devoid of atmosphere with low-viscosity magma flows at the surface. PMID:27027283

  5. A map of the large day-night temperature gradient of a super-Earth exoplanet.

    Science.gov (United States)

    Demory, Brice-Olivier; Gillon, Michael; de Wit, Julien; Madhusudhan, Nikku; Bolmont, Emeline; Heng, Kevin; Kataria, Tiffany; Lewis, Nikole; Hu, Renyu; Krick, Jessica; Stamenković, Vlada; Benneke, Björn; Kane, Stephen; Queloz, Didier

    2016-04-14

    Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres, but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths--exoplanets with masses of one to ten times that of Earth--have so far revealed only featureless spectra. Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e (refs 4, 5) revealing highly asymmetric dayside thermal emission and a strong day-night temperature contrast. Dedicated space-based monitoring of the planet in the infrared revealed a modulation of the thermal flux as 55 Cancri e revolves around its star in a tidally locked configuration. These observations reveal a hot spot that is located 41 ± 12 degrees east of the substellar point (the point at which incident light from the star is perpendicular to the surface of the planet). From the orbital phase curve, we also constrain the nightside brightness temperature of the planet to 1,380 ± 400 kelvin and the temperature of the warmest hemisphere (centred on the hot spot) to be about 1,300 kelvin hotter (2,700 ± 270 kelvin) at a wavelength of 4.5 micrometres, which indicates inefficient heat redistribution from the dayside to the nightside. Our observations are consistent with either an optically thick atmosphere with heat recirculation confined to the planetary dayside, or a planet devoid of atmosphere with low-viscosity magma flows at the surface.

  6. Uma síntese alternativa para o (±-1,2,3,4-tetraidro-{9H-pirido-[3,4-b]}-indol An alternative synthesis of 1,2,3,4-tetrahydro-9H-pyrido-[3,4-b]-indole

    Directory of Open Access Journals (Sweden)

    Arildo José Braz de Oliveira

    2003-09-01

    Full Text Available O 1,2,3,4-tetraidro-9H-pirido-[3,4-b]-indol, um composto com propriedades tranqüilizantes, foi preparado a partir do 3-indol-acetaldeído e triptamina através de uma reação de condensação de Pictet-Spengler. Os dados físicos e espectrais do composto são apresentados.The 1,2,3,4-tetrahydro-9H-pyrido-[3,4-b]-indole, a compound with tranquillizing properties, was prepared in 16% overall yield from the 3-indole-acetaldehyde and tryptamine by applying the classical Pictet-Spengler condensation. Physical and spectroscopic data for such compound are presented.

  7. Re-examination of the "3/4-law" of Metabolism

    CERN Document Server

    Dodds, P S; Weitz, J S; Dodds, Peter Sheridan; Rothman, Daniel H.; Weitz, Joshua S.

    2000-01-01

    We examine the scaling law $B \\propto M^{\\alpha}$ which connects organismal metabolic rate $B$ with organismal mass $M$, where $\\alpha$ is commonly held to be 3/4. Since simple dimensional analysis suggests $\\alpha=2/3$, we consider this to be a null hypothesis testable by empirical studies. We re-analyze data sets for mammals and birds compiled by Heusner, Bennett and Harvey, Bartels, Hemmingsen, Brody, and Kleiber, and find little evidence for rejecting $\\alpha=2/3$ in favor of $\\alpha=3/4$. For mammals, we find a possible breakdown in scaling for larger masses reflected in a systematic increase in $\\alpha$. We also review theoretical justifications of $\\alpha=3/4$ based on dimensional analysis, nutrient-supply networks, and four-dimensional biology. We find that present theories for $\\alpha=3/4$ require assumptions that render them unconvincing for rejecting the null hypothesis that $\\alpha=2/3$.

  8. Human reliability analysis in Wolsong 2/3/4 nuclear power plants probabilistic safety assessment

    International Nuclear Information System (INIS)

    The Level 1 probabilistic safety assessment (PSA) for Wolsong(WS) 2/3/4 nuclear power plant(NPPs) in design stage is performed using the methodologies being equivalent to PWR PSA. Accident sequence evaluation program (ASEF) human reliability analysis (HRA) procedure and technique for human error rate prediction (THERP) are used in HRA of WS 2/3/4 NPPs PSA. The purpose of this paper is to introduce the procedure and methodology of HRA in WS 2/3/4 NPPs PSA. Also, this paper describes the interim results of importance analysis for human actions modeled in WS 2/3/4 PSA and the findings and recommendations of administrative control of secondary control area from the view of human factors

  9. Identification of a Kir3.4 Mutation in Congenital Long QT Syndrome

    DEFF Research Database (Denmark)

    Yang, Yanzong; Yang, Yiqing; Liang, Bo;

    2010-01-01

    , 49 individuals) with autosomal-dominant LQTS was clinically evaluated. Genome-wide linkage analysis was performed by using polymorphic microsatellite markers to map the genetic locus, and positional candidate genes were screened by sequencing for mutations. The expression pattern and functional...... characteristics of the mutated protein were investigated by western blotting and patch-clamp electrophysiology. The genetic locus of the LQTS-associated gene was mapped to chromosome 11q23.3-24.3. A heterozygous mutation (Kir3.4-Gly387Arg) was identified in the G protein-coupled, inwardly rectifying potassium...... channel subunit Kir3.4, encoded by the KCNJ5 gene. The Kir3.4-Gly387Arg mutation was present in all nine affected family members and absent in 528 ethnically matched controls. Western blotting of human cardiac tissue demonstrated significant Kir3.4 expression levels in the cardiac ventricles. Heterologous...

  10. Local surface potential of π-conjugated nanostructures by Kelvin probe force microscopy: effect of the sampling depth.

    Science.gov (United States)

    Liscio, Andrea; Palermo, Vincenzo; Fenwick, Oliver; Braun, Slawomir; Müllen, Klaus; Fahlman, Mats; Cacialli, Franco; Samorí, Paolo

    2011-03-01

    Kelvin probe force microscopy (KPFM) is usually applied to map the local surface potential of nanostructured materials at surfaces and interfaces. KPFM is commonly defined as a 'surface technique', even if this assumption is not fully justified. However, a quantification of the surface sensitivity of this technique is crucial to explore electrical properties at the nanoscale. Here a versatile 3D model is presented which provides a quantitative explanation of KPFM results, taking into account the vertical structure of the sample. The model is tested on nanostructured films obtained from two relevant semiconducting systems for field-effect transistor and solar cell applications showing different interfacial properties, i.e., poly(3-hexylthiophene) (P3HT) and perylene-bis-dicarboximide (PDI). These findings are especially important since they enable quantitative determination of the local surface potential of conjugated nanostructures, and thereby pave the way towards optimization of the electronic properties of nanoscale architectures for organic electronic applications.

  11. Sub-Kelvin single flux quantum control circuits and multi-chip packaging for supporting superconducting qubit

    International Nuclear Information System (INIS)

    Superconducting single flux quantum (SFQ) circuit can operate at very low temperature. This is suitable for controlling a quantum computing system with Josephson junctions. However, it is difficult to integrate both SFQ circuits and qubits into a single-chip, because of the dissipative characteristics of SFQ circuits. Therefore, we have developed a multi-chip packaging technology for a qubit control module. The module consists of SFQ circuit chips, qubit chips, and a substrate all of which are fabricated with Nb and Al technology. The chips are flip-chip bonded with superconducting solder bumps. We also investigated SFQ control circuits for superconducting qubits and circuit parameter optimization for sub-Kelvin temperature operation. Using both multi-chip packaging and optimized SFQ control circuit makes the design of qubit control module more flexible

  12. Cross-Sectional Investigations on Epitaxial Silicon Solar Cells by Kelvin and Conducting Probe Atomic Force Microscopy: Effect of Illumination.

    Science.gov (United States)

    Narchi, Paul; Alvarez, Jose; Chrétien, Pascal; Picardi, Gennaro; Cariou, Romain; Foldyna, Martin; Prod'homme, Patricia; Kleider, Jean-Paul; I Cabarrocas, Pere Roca

    2016-12-01

    Both surface photovoltage and photocurrent enable to assess the effect of visible light illumination on the electrical behavior of a solar cell. We report on photovoltage and photocurrent measurements with nanometer scale resolution performed on the cross section of an epitaxial crystalline silicon solar cell, using respectively Kelvin probe force microscopy and conducting probe atomic force microscopy. Even though two different setups are used, the scans were performed on locations within 100-μm distance in order to compare data from the same area and provide a consistent interpretation. In both measurements, modifications under illumination are observed in accordance with the theory of PIN junctions. Moreover, an unintentional doping during the deposition of the epitaxial silicon intrinsic layer in the solar cell is suggested from the comparison between photovoltage and photocurrent measurements. PMID:26831693

  13. 1-D transient numerical model of a regenerator in a novel sub Kelvin Active Magnetic Regenerative Refrigerator

    Science.gov (United States)

    Jahromi, Amir E.; Miller, Franklin K.

    2016-03-01

    A sub Kelvin Active Magnetic Regenerative Refrigerator (AMRR) is being developed at the University of Wisconsin - Madison. This AMRR consists of two circulators, two regenerators, one superleak, one cold heat exchanger, and two warm heat exchangers. The circulators are novel non-moving part pumps that reciprocate a superfluid mixture of 4He-3He in the system. Heat from the mixture is removed within the two regenerators of this tandem system. An accurate model of the regenerators in this AMRR is necessary in order to predict the performance of these components, which in turn helps predicting the overall performance of the AMRR system. This work presents modeling methodology along with results from a 1-D transient numerical model of the regenerators of an AMRR capable of removing 2.5 mW at 850 mK at cyclic steady state.

  14. Nanoscale interface mapping of a CdS-CZTS single nanorod heterojunction using Kelvin probe force microscopy

    Science.gov (United States)

    Gupta, Saatviki; Varandani, Deepak; Sharma, A. K.; Satsangi, V. R.; Mehta, B. R.

    2015-03-01

    In the present study, Kelvin probe force microscopy (KPFM) has been used to study a prototype CdS-CZTS lengthwise single nanorod heterojunction. A shift in surface potential (SP) of the entire sample is observed as the device is taken from dark into light. It has been demonstrated that plots showing the number of pixels with different values of surface potential as a function of the SP itself, can be effectively used to topographically segregate regions composed of different semiconductors. On illumination, a new SP peak emerges and based on its topographical position and SP value, both of which lie in between that of CZTS and CdS, it has been assigned to the heterojunction interfacial layer. These observations have been discussed in terms of junction quality and charge generation and separation to gain a better understanding of the operation of nanorod based solar cell devices.

  15. Upper critical field of the 3 Kelvin phase in Sr sub 2 RuO sub 4

    CERN Document Server

    Matsumoto, M; Sigrist, M

    2003-01-01

    The inhomogeneous 3 Kelvin phase is most likely a superconducting state nucleating at the interface between micrometer-sized Ru-metal inclusions and Sr sub 2 RuO sub 4 above the bulk onset of superconductivity. This filamentary superconducting state yields a characteristic temperature dependence of the upper critical field which is sublinear, i.e., H sub c sub 2 (T) propor to (T* - T) supgamma with 0.5 <= gamma< 1 (T*: nucleation temperature). The Ginzburg-Landau theory is used to analyze the behavior of the nucleated spin-triplet phase in a field and the characteristic features of H sub c sub 2 observed in the experiment are explained based on a two-component order parameter in the presence of a filament of enhanced superconductivity with a finite width. (author)

  16. Efficient magnetic-field amplification due to the Kelvin-Helmholtz instability in binary neutron star mergers

    CERN Document Server

    Kiuchi, Kenta; Kyutoku, Koutarou; Sekiguchi, Yuichiro; Shibata, Masaru

    2015-01-01

    We explore magnetic-field amplification due to the Kelvin-Helmholtz instability during binary neutron star mergers. By performing high-resolution general relativistic magnetohydrodynamics simulations with a resolution of $17.5$ m for $4$--$5$ ms after the onset of the merger on the Japanese supercomputer "K", we find that an initial magnetic field of moderate maximum strength $10^{13}$ G is amplified at least by a factor of $\\approx 10^3$. We also explore the saturation of the magnetic-field energy and our result shows that it is likely to be $\\gtrsim 4 \\times 10^{50}$ erg, which is $\\gtrsim 0.1\\%$ of the bulk kinetic energy of the merging binary neutron stars.

  17. Progress toward Kelvin-Helmholtz instabilities in a High-Energy-Density Plasma on the Nike laser

    Science.gov (United States)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Huntington, C. M.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Plewa, T.; Dwarkadas, V. V.

    2008-04-01

    In the realm of high-energy-density (HED) plasmas, there exist three primary hydrodynamic instabilities of concern: Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH). Although the RT and the RM instabilities have been readily observed and diagnosed in the laboratory, the KH instability remains relatively unexplored in HED plasmas. Unlike the RT and RM instabilities, the KH instability is driven by a lifting force generated by a strong velocity gradient in a stratified fluid. Understanding the KH instability mechanism in HED plasmas will provide essential insight into oblique shock systems, jets, mass stripping, and detailed RT-spike development. In addition, our KH experiment will help provide the groundwork for future transition to turbulence experiments. We present 2D FLASH simulations and experimental data from our initial attempts to create a pure KH system using the Nike laser at the Naval Research Laboratory.

  18. Molecular Dynamics simulations and Kelvin Probe Force microscopy to study of cholesterol-induced electrostatic nanodomains in complex lipid mixtures

    CERN Document Server

    Drolle, Elizabeth; Bennett, W F D; Lyman, Edward; Karttunen, Mikko; Leonenko, Zoya

    2016-01-01

    The molecular arrangement of lipids and proteins within biomembranes and monolayers gives rise to complex film morphologies as well as regions of distinct electrical surface potential, topographical and electrostatic nanoscale domains. To probe these nanodomains in soft matter is a challenging task both experimentally and theoretically. This work addresses the effects of cholesterol, lipid composition, lipid charge, and lipid phase on the monolayer structure and the electrical surface potential distribution. Atomic Force Microscopy (AFM) was used to resolve topographical nanodomains and Kelvin Probe Force Microscopy (KPFM) to resolve electrical surface potential of these nanodomains in lipid monolayers. Model monolayers composed of dipalmitoylphosphatidylcholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dioleoyl-sn-glycero-3-[phospho-rac-(3-lysyl(1-glycerol))] (DOPG), sphingomyelin, and cholesterol were studied. It is shown that chole...

  19. Magnetic phase transitions in new multiferroic SmCr3(BO3)4

    International Nuclear Information System (INIS)

    The optical spectra, as well as thermal and magnetic properties, of the compound SmCr3(BO3)4, both pure and doped with 1% erbium, have been investigated in a wide temperature range. It has been found that SmCr3(BO3)4 undergoes a cascade of phase transitions at temperatures (7.8±0.5) K, (6.7±0.5) K, and (4.3±0.2) K

  20. New 3,4-seco-ent-kaurene dimers from Croton micans.

    Science.gov (United States)

    Mateu, Elsa; Chavez, Katiuska; Riina, Ricarda; Compagnone, Reinaldo S; Delle Monache, Franco; Suárez, Alírica I

    2012-01-01

    From the stems of Croton micans Sw., five new 3,4-seco-ent-kaurene dimers: micansinoic acid (1), isomicansinoic acid (2), and the dimethyl (3), monomethyl (4) and monoethyl ester (5) of micansinoic acid were isolated. The structures of the new compounds were elucidated by spectroscopic data interpretation, mainly 1D and 2D NMR experiments and MS. These compounds are the first 3,4-seco-ent-kaurene dimers from a Croton species. PMID:22428229

  1. N-[(9-Ethyl-9H-carbazol-3-ylmethylene]-3,4-dimethylisoxazol-5-amine

    Directory of Open Access Journals (Sweden)

    Abdullah Mohamed Asiri

    2010-05-01

    Full Text Available The title compound, N-[(9-ethyl-9H-carbazol-3-ylmethylene]-3,4-dimethylisoxazol-5-amine has been synthesized by reaction of 9-ethyl-9H-carbazole-3-carbaldehyde with 5-amino-3,4-dimethylisoxazole in the presence of acetic acid in ethanol. The structure of this new compound was confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and EI-MS spectral analysis.

  2. n-Propyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside

    Directory of Open Access Journals (Sweden)

    Bettina Mönch

    2013-02-01

    Full Text Available The title compound [systematic name: (2R,3R,4S,5R,6R-2-(acetoxymethyl-6-propoxytetrahydro-2H-pyran-3,4,5-triyl triacetate], C17H26O10, was formed by a Koenigs–Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide and n-propanol. The central ring adopts a chair conformation. The crystal does not contain any significant interactions such as hydrogen bonds.

  3. First observations of Kelvin-Helmholtz billows in an upper level jet stream using VHF frequency domain interferometry

    Science.gov (United States)

    Chilson, Phillip B.; Muschinski, Andreas; Schmidt, Gerhard

    1997-05-01

    In this paper we report the first high-resolution observations of upper tropospheric Kelvin-Helmholtz billows using VHF frequency domain interferometry (FDI). The measurements were made using the sounding system VHF radar located in the German Harz Mountains operating at the frequencies of 53.25 and 53.75 MHz. Through an application of the FDI technique it has been possible to track the altitude of thin scattering layers with an accuracy of a few tens of meters and a temporal resolution of 13 s. Taking advantage of the FDI technique, we found several examples of Kelvin-Helmholtz instability (KHI) in regions coinciding with large values of wind shear. One particularly good example is presented in detail. The KHI occurred just below the axis of the jet at an altitude of 9.1 km. It produced oscillations in the vertical velocity field in the altitude range of 8-10 km. The oscillations had a local period of 90 s and persisted over a time interval of 10 min. On the basis of the magnitude of the horizontal wind at the time and height of the KHI, the billow train had a horizontal extent of about 27 km, while the horizontal length of the individual billow amounted to about 4.0 km. The 90-s oscillations were also observed in the radar signal power, the FDI-derived layer height, and the coherence between the received radar signals for the two frequencies. Using the FDI data, we were able to identify the individual billows located within the train and observe their maximum crest-to-trough amplitudes to be between 220 and 230 m. This was less than the conventional radar resolution of 300 m used during the experiment.

  4. Turbulent Mixing and Transport of the Solar Wind Plasma : Full Particle Simulation Study of the Kelvin-Helmholtz Instability

    Science.gov (United States)

    Matsumoto, Y.; Hoshino, M.

    2004-12-01

    Recent in-situ observations often show the mixing of the solar wind and magnetospheric plasmas in the low latitude boundary layer (LLBL), in which the Kelvin-Helmholtz instability is considered to be unstable. Those suggest that LLBL is a candidate for a source of plasmas and the Kelvin-Helmholtz instability plays an crucial role in a new transport mechanism. Even though numerous theoretical and computational studies have challenged to explain it so far, no one succeeded in transport of plasmas over a K-H vortex size and diffusive process that explains the observations. Hence, the transport mechanism of the solar wind plasma into the Earth magnetosphere in the situation of northward IMF has been a hot topic in magnetospheric physics. To elucidate the mixing and transport mechanism of the solar wind plasma we carried out two dimensional full particle simulation of the K-H instability. As a result, the strong density stratification triggered the strong turbulence which was also found in the two-dimensional MHD simulation (Matsumoto and Hoshino, GRL, 2004). The secondary Rayleigh-Taylor instability was found out to be unstable inside the stratified vortex structure and transport the dense solar wind plasma deep inside the magnetosphere. The resultant mixing area of the two plasmas increased anomalously fast as compared with the uniform density case. Hence the density stratification is an important factor for the effective mass transport across the velocity shear layer. The density stratification also introduced the ion kinetic effect in the non-linear stage. In a negative shear layer (the dawn side of the magnetopause) the finite Larmor radius (FLR) effect of the ion stabilized the onset of the secondary R-T instability and thus weakened the mass transport. In this presentation, the dawn-dusk asymmetry in the transport mechanism will be presented in detail as well as the onset mechanism of the turbulent mixing and transport by the K-H instability.

  5. CERN hearing day

    CERN Multimedia

    2005-01-01

    1 in 10 people suffer from hearing loss ? do you? The Medical Service invites everyone working on the CERN site to participate in the NATIONAL HEARING DAY on: Thursday 10th March 2005 From 9am to 4pm The Infirmary, Blg. 57, Ground Floor We will be offering hearing tests (audiograms), as well as information and advice on hearing loss, tinnitus, etc. Deafness does not just affect the elderly: in Europe, 50% of the hearing-impaired are under the age of 55. Exposure to excessive noise is one of the main reasons for hearing problems but prevention is possible. For example, hearing protection devices can prevent 80% of tinnitus cases.

  6. CERN hearing day

    CERN Multimedia

    2005-01-01

    1 in 10 people suffer from hearing loss - do you? The Medical Service invites everyone working on the CERN site to participate in the NATIONAL HEARING DAY on: Thursday 10th March 2005 From 9am to 4pm The Infirmary, Blg. 57, Ground Floor We will be offering hearing tests (audiograms), as well as information and advice on hearing loss, tinnitus, etc. Deafness does not just affect the elderly: in Europe, 50% of the hearing-impaired are under the age of 55. Exposure to excessive noise is one of the main reasons for hearing problems but PREVENTION IS POSSIBLE. For example, hearing protection devices can prevent 80% of tinnitus cases.

  7. CERN hearing day

    CERN Document Server

    2005-01-01

    1 in 10 people suffer from hearing loss - do you? The Medical Service invites everyone working on CERN premises to participate in the National Hearing Day on: Thursday 10th March From 9am to 4pm The Infirmary, Blg. 57, Gr.Fl. We will be offering hearing tests (audiogram); information, advice on hearing loss, tinnitus and more. Deafness does not just affect the elderly: in Europe, 50% the hearing-impaired are under the age of 55. Exposure to excessive noise is one of the main reasons for hearing loss. But prevention is possible and effective: for example, Hearing protection devices could reduce tinnitus cases by 80%.

  8. CERN hearing day

    CERN Document Server

    2005-01-01

    1 in 10 people suffer from hearing loss - do you? The Medical Service invites everyone working on CERN premises to participate in the National Hearing Day on: Thursday 10th March From 9am to 4pm The Infirmary, Blg. 57, Gr.Fl. We will be offering hearing tests (audiogram); information, advice on hearing loss, tinnitus and more. Deafness does not just affect the elderly: in Europe, 50% the hearing-impaired are under the age of 55. Exposure to excessive noise is one of the main reasons for hearing loss. But PREVENTION IS POSSIBLE AND EFFECTIVE: for example, Hearing protection devices could reduce tinnitus cases by 80%.

  9. One cold autumn day.

    Science.gov (United States)

    de Schweinitz, Peter

    2015-01-01

    Behavioral change is at the heart of effective primary care, but when patients don't change, how do we account for our days? In this personal essay, I relate an encounter with a patient who wants to quit smoking, lose weight, and control her diabetes. I am discouraged when she deflects my recommendations, but a colleague's comment encourages a deeper inquiry. Knowing the patient's story and deepening the conversation, however, do not guarantee change. The experience reminds me why patience, humility, and faith are core values of the primary care physician. PMID:25964410

  10. Have a Good Day

    Institute of Scientific and Technical Information of China (English)

    王秋海

    2002-01-01

    几次在一些场合和学生交谈,分手时道一声:Have a good day!,然而令我哑然的是,多数人竟反问我:I beg your pardon?让我啼笑皆非,弄得双方都很尴尬。有些人反应片刻似乎明白了此话的意思,但却不知如何作答,只好嗫嚅着发窘。

  11. Hard-hat day

    CERN Multimedia

    2003-01-01

    CERN will be organizing a special information day on Friday, 27th June, designed to promote the wearing of hard hats and ensure that they are worn correctly. A new prevention campaign will also be launched.The event will take place in the hall of the Main Building from 11.30 a.m. to 2.00 p.m., when you will be able to come and try on various models of hard hat, including some of the very latest innovative designs, ask questions and pass on any comments and suggestions.

  12. Signatures of 3–6 day planetary waves in the equatorial mesosphere and ionosphere

    Directory of Open Access Journals (Sweden)

    B. R. Clemesha

    2006-12-01

    Full Text Available Common periodic oscillations have been observed in meteor radar measurements of the MLT winds at Cariri (7.4° S, 36.5° W and Ascension Island (7.9° S, 14.4° W and in the minimum ionospheric virtual height, h'F, measured at Fortaleza (3.9° S, 38.4° W in 2004, all located in the near equatorial region. Wavelet analysis of these time series reveals that there are 3–4-day, 6–8-day and 12–16-day oscillations in the zonal winds and h'F. The 3–4 day oscillation appeared as a form of a wave packet from 7–17 August 2004. From the wave characteristics analyzed this might be a 3.5-day Ultra Fast Kelvin wave. The 6-day oscillation in the mesosphere was prominent during the period of August to November. In the ionosphere, however, it was apparent only in November. Spectral analysis suggests that this might be a 6.5-day wave previously identified. The 3.5-day and 6.5-day waves in the ionosphere could have important roles in the initiation of equatorial spread F (plasma bubble. These waves might modulate the post-sunset E×B uplifting of the base of the F-layer via the induced lower thermosphere zonal wind and/or the E-region conductivity.

  13. Higgs Boson Pizza Day

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    CERN celebrated the fourth anniversary of the historical Higgs boson announcement with special pizzas.    400 pizzas were served on Higgs pizza day in Restaurant 1 at CERN to celebrate the fourth anniversary of the announcement of the discovery of the Higgs Boson (Image: Maximilien Brice/ CERN) What do the Higgs boson and a pizza have in common? Pierluigi Paolucci, INFN and CMS collaboration member, together with INFN president Fernando Ferroni found out the answer one day in Naples: the pizza in front of them looked exactly like a Higgs boson event display. A special recipe was then created in collaboration with the chef of the historic “Ettore” pizzeria in the St. Lucia area of Naples, and two pizzas were designed to resemble two Higgs boson decay channel event displays. The “Higgs Boson Pizza Day” was held on Monday, 4 July 2016, on the fourth anniversary of the announcement of the discovery of the Higgs boso...

  14. A day to celebrate

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    After several weeks of preparations and hard work on the part of many people, the events to mark International Women's Day at CERN on 8 March were a genuine success. They were followed with great interest by the outside world, judging by the flurry of activity on twitter, various blogs and the media coverage they generated.   Women on shift in the CERN control rooms. Women were overwhelmingly in the majority at the controls of the experiments and accelerators throughout the day, as well as acting as the guides for all official visits. There was no shortage of enthusiasm! "I'm very happy that CERN has supported the project, and I'm especially encouraged by the enthusiastic response from everyone who's taken part", says Pauline Gagnon, a physicist from the Indiana University group and a member of the ATLAS collaboration, who was behind the idea. "I hope that this kind of initiative will help to show that women have a place in science and that young women thinkin...

  15. 5th Optimization Day

    CERN Document Server

    Mees, Alistair; Fisher, Mike; Jennings, Les

    2000-01-01

    'Optimization Day' (OD) has been a series of annual mini-conferences in Australia since 1994. The purpose of this series of events is to gather researchers in optimization and its related areas from Australia and their collaborators, in order to exchange new developments of optimization theories, methods and their applications. The first four OD mini-conferences were held in The Uni­ versity of Ballarat (1994), The University of New South Wales (1995), The University of Melbourne (1996) and Royal Melbourne Institute of Technology (1997), respectively. They were all on the eastern coast of Australia. The fifth mini-conference Optimization Days was held at the Centre for Ap­ plied Dynamics and Optimization (CADO), Department of Mathematics and Statistics, The University of Western Australia, Perth, from 29 to 30 June 1998. This is the first time the OD mini-conference has been held at the west­ ern coast of Australia. This fifth OD preceded the International Conference on Optimization: Techniques and Applica...

  16. Nuclear Power Day '86

    International Nuclear Information System (INIS)

    The proceedings in two volumes of the event ''Nuclear Power Day '86'' held in the Institute of Nuclear Research, contain full texts of 13 papers which all fall under the INIS Scope. The objective of the event was to acquaint broad technical public with the scope of the State Research and Development Project called ''Development of Nuclear Power till the Year 2000''. The papers were mainly focused on increased safety and reliability of nuclear power plants with WWER reactors, on the development of equipment and systems for disposal and burial of radioactive wastes, the introduction of production of nuclear power facilities of an output of 1,000 MW, and on the construction of nuclear heat sources. (Z.M.)

  17. World AIDS Day 1998.

    Science.gov (United States)

    1999-01-01

    Excerpts of speeches given at a public rally on World AIDS Day 1998 underscore the need to energize support for those living with HIV/AIDS, emphasize the importance of increasing public education efforts, and memorialize those lost to the disease. Reverend Pat Bumgardner stressed the need to educate children about practicing safe sex and the dangers of drug use. He also focused attention on AIDS as a worldwide crisis, with the 30 million people who have HIV or AIDS. Councilwoman Margarita Lopez spoke about achieving objectives and securing resources through activism. She also condemned New York City's Mayor for trying to hinder the rally. Anne Chelimsky, who did not speak at the rally but attended it, reflected on her new role as an activist, and on how the rally affected her. PMID:11367196

  18. CERN Heart Days

    CERN Multimedia

    2003-01-01

    14 & 15 OCTOBER 2003 The Medical Service and the Fire Brigade invite everyone working at CERN to participate in the above event. INFIRMARY 9 am to 16.30 pm Building 57, ground floor HEALTHY HEART? ♥ Evaluation of personal cardiac risks through the monitoring of: • Blood pressure • Cholesterol and sugar levels • Body Mass Index ... and more ♥ Leaflets, information and advice concerning cardiac issues FIRE BRIGADE 9 to 12am Building 65 FIRST AID COURSES ♥ What to do in a Cardiac Emergency (3 h duration) Places are limited and on reservation only (15 people / day) To book, E-mail the Medical Services on: service.medical@cern.ch

  19. Occlusal relationships and spacing or crowding of teeth in the dentitions of 3-4-year-old Nigerian children.

    Science.gov (United States)

    Otuyemi, O D; Sote, E O; Isiekwe, M C; Jones, S P

    1997-09-01

    A study of 525 3-4-year-old children in nursery schools and day-care centres was carried out to assess occlusal relationships and the presence of spacing or crowding of teeth. No significant differences in occlusal relationships were found between boys and girls (P > 0.05). Bilateral straight terminal planes of molars and class 1 canine relationship were the most prevalent features (74.5% and 73.3% respectively). Most of the children had 'normal' vertical and transverse occlusal relationships. The most common sites of spacing were mesial to maxillary canines and distal to mandibular canines. 32% of the children were found to have generalized anterior segment spacing, 4% showed exclusively anthropoid spaces, and 18% had either contact between all the teeth or crowding in the anterior region.

  20. Novel lanthanide complexes constructed from 3, 4-dimethoxybenzoic acid: crystal structures, spectrum and thermochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiao-Xia; Wu, Jun-Chen [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Ren, Ning, E-mail: ningren9@163.com [College of Chemical engineering & Material, Handan College, Handan 056005 (China); Zhao, Chun-Li [Raoyang High School of Hebei, Raoyang 053900 (China); Zhang, Jian-Jun, E-mail: jjzhang6@126.com [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Zong, Guang-Cai; Gao, Jie [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China)

    2015-09-10

    Graphical abstract: Four novel lanthanide coordination polymers [Ln(3,4-DMOBA){sub 3}(H{sub 2}O){sub 2}]·H{sub 2}O·C{sub 2}H{sub 5}OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Single crystal structures indicates 1 D stucture of the title complexes are linked by hydrogen bonds to form a three-dimensional (3-D) structure. Complex 2 exhibits the characteristic emission of Tb{sup 3+} ion({sup 5}D{sub 4} → {sup 7}F{sub 6-3}). The investigation of TG-FTIR and IR spectra of the evolved gases shows uncoordinated water and ethanol molecules tend to lose firstly, and then 3,4-DMOBA ligands begin to decompose. - Highlights: • Four lanthanide coordination polymers were synthesized and characterized. • 1-D chain structures of the title complexes are are linked by hydrogen bonds to form a 3-D structures. • Thermal decomposition processes of the title complexes were studied using TG-FTIR techniques. • IR spectra of evolved gases in thermal decomposition process were obtained and analyzed. - Abstract: Four novel lanthanide complexes [Ln(3,4-DMOBA){sub 3}(H{sub 2}O){sub 2}]·H{sub 2}O·C{sub 2}H{sub 5}OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Structural analyses reveal that adjacent lanthanide ions are connected by 3,4-DMOBA ligands adopting bridging bidentate mode to generate one-dimensional (1-D) structure with the uncoordinated water and ethanol molecules. 1-D structures are linked by hydrogen bonds to form a three-dimensional (3-D) structure, which is rarely observed in lanthanide carboxylic acids complexes. Under the radiation of UV light, complex 2 exhibits the characteristic emission of Tb{sup 3+} ion ({sup 5}D{sub 4} → {sup 7}F{sub 6-3}). The thermal decomposition mechanism is investigated by TG-FTIR technology. IR spectra of the evolved gases show that the uncoordinated water and ethanol

  1. Mechanism of 3,4-dihydroxybenzaldehyde electropolymerization at carbon paste electrodes : catalytic detection of NADH

    Directory of Open Access Journals (Sweden)

    Delbem Maria Flávia

    2002-01-01

    Full Text Available Cyclic voltammetry was used to study 3,4-dihydroxybenzaldehyde (3,4-DHB electropolymerization processes on carbon paste electrodes. The characteristics of the electropolymerized films were highly dependent on pH, anodic switching potential, scan rate, 3,4-DHB concentrations and number of cycles. Film stability was determined in citrate/phosphate buffer solutions at the same pH used during the electropolymerization process. The best conditions to prepare carbon paste modified electrodes were pH 7.8; 0.0 <= Eapl <= 0.25 V; 10 mV s-1; 0.25 mmol L-1 3,4-DHB and 10 scans. These carbon paste modified electrodes were used for NADH catalytic detection at 0.23 V in the range 0.015 <= [NADH] <= 0.21 mmol L-1. Experimental data were used to propose a mechanism for the 3,4--DHB electropolymerization processes, which involves initial phenoxyl radical formation.

  2. High cervical C3-4 ′disc′ compression associated with basilar invagination

    Directory of Open Access Journals (Sweden)

    Goel Atul

    2008-01-01

    Full Text Available A 20-year-old male had torticollis and short neck since birth. He presented with symptom of progressive quadriparesis over a two-year period. Investigations revealed basilar invagination with marked rotation in the craniovertebral region and relatively large C3-4 region osteophytes. Serial MRI over two years showed persistent signal opposite C3-4 disc space suggestive of cord compression. Although the cord was humped over the odontoid process, there was no clear radiological evidence that the cord was compromised at this level. During surgery, instability was identified only at the craniovertebral region and not at the level of C3-4. Distraction of the lateral masses of atlas and axis and fixation using interarticular spacers and bone graft and direct screw implantation in the lateral mass of the atlas and pars of the axis resulted in reduction of the basilar invagination and of atlantoaxial dislocation. The patient had marked clinical recovery, despite the fact that no direct procedure was done for C3-4 disc decompression. The case suggests that C3-4 disc changes could be secondary to primary instability at the craniovertebral junction.

  3. 3',4'-Dihydroxyflavonol reduces superoxide and improves nitric oxide function in diabetic rat mesenteric arteries.

    Directory of Open Access Journals (Sweden)

    Chen-Huei Leo

    Full Text Available BACKGROUND: 3',4'-Dihydroxyflavonol (DiOHF is an effective antioxidant that acutely preserves nitric oxide (NO activity in the presence of elevated reactive oxygen species (ROS. We hypothesized that DiOHF treatment (7 days, 1 mg/kg per day s.c. would improve relaxation in mesenteric arteries from diabetic rats where endothelial dysfunction is associated with elevated oxidant stress. METHODOLOGY/PRINCIPAL FINDINGS: In mesenteric arteries from diabetic rats there was an increase in ROS, measured by L-012 and 2',7'-dichlorodihydrofluorescein diacetate fluorescence. NADPH oxidase-derived superoxide levels, assayed by lucigenin chemiluminescence, were also significantly increased in diabetic mesenteric arteries (diabetes, 4892±946 counts/mg versus normal 2486±344 counts/mg, n = 7-10, p<0.01 associated with an increase in Nox2 expression but DiOHF (2094±300 counts/mg, n = 10, p<0.001 reversed that effect. Acetylcholine (ACh-induced relaxation of mesenteric arteries was assessed using wire myography (pEC(50 = 7.94±0.13 n = 12. Diabetes significantly reduced the sensitivity to ACh and treatment with DiOHF prevented endothelial dysfunction (pEC(50, diabetic 6.86±0.12 versus diabetic+DiOHF, 7.49±0.13, n = 11, p<0.01. The contribution of NO versus endothelium-derived hyperpolarizing factor (EDHF to ACh-induced relaxation was assessed by evaluating responses in the presence of TRAM-34+apamin+iberiotoxin or N-nitro-L-arginine+ODQ respectively. Diabetes impaired the contribution of both NO (maximum relaxation, R(max diabetic 24±7 versus normal, 68±10, n = 9-10, p<0.01 and EDHF (pEC(50, diabetic 6.63±0.15 versus normal, 7.14±0.12, n = 10-11, p<0.01 to endothelium-dependent relaxation. DiOHF treatment did not significantly affect the EDHF contribution but enhanced NO-mediated relaxation (R(max 69±6, n = 11, p<0.01. Western blotting demonstrated that diabetes also decreased expression and increased uncoupling of

  4. Long-term effects of inhaled Ca-DTPA in rats previously exposed to 239Pu(NO3)4 aerosols

    International Nuclear Information System (INIS)

    Inhaled Ca-DTPA given 20 days after 239Pu(NO3)4 inhalation was marginally effective (p = 0.10) in reducing the amount of Pu in rat lung. This reduction in Pu lung burden did not, however, affect the later induction of lung tumors. An increased osteosarcoma incidence was noted in control rats exposed only to nitric acid aerosols. Complete tumor incidence data are not yet available. (U.S.)

  5. A response of L-α-alanine and standard bone powder on 3.4 MeV/amu 59Co ion beams

    International Nuclear Information System (INIS)

    Dosimetric response of microcrystaline L-α-alanine and standard bovine bone powder on 3.4 MeV/amu 59Co ions (LET ∼5500 eV/nm) was investigated. The long-lived paramagnetic centers created by ion beams were measured after 51 and 420 days. Relative sensitivity compared to gamma rays was estimated at 0.2 for L-α-alanine and 0.15 for standard bovine bone powder. (Author)

  6. Synthesis and evaluation of antimicrobial activity of novel 1,3,4-oxadiazole derivatives

    Directory of Open Access Journals (Sweden)

    Popat B. Mohite

    2011-09-01

    Full Text Available In attempt to find new pharmacologically active molecules, we report here the synthesis and in vitro antimicrobial activities of various novel 1,3,4-oxadiazole containing 5-phenyltetrazole. The Schiff bases were obtained by condensation 2-(5-phenyl-1H-tetrazol-1-ylacetohydrazide with various aromatic aldehydes. Cyclocondensation of Schiff’s bases with acetic anhydride results in 1,3,4-oxadiazole derivatives. The structures of the newly synthesized 1,3,4-oxadiazole were confirmed by FT-IR, 1H NMR and mass spectral data. The antimicrobial activity was determined by MIC method. All the compounds exhibited weak to potent antimicrobial activity. Some derivatives bearing a methoxy group exhibited very good antimicrobial activity at conc. of 62.5 µg/mL.

  7. Synthesis of 1,2-bis[2-methyl-5(3,4-difluorophenyl)-3-thienyl] perfluorocyclopentene

    Institute of Scientific and Technical Information of China (English)

    Taiqi LIU; Liyan YANG; Jianxiang YU

    2008-01-01

    2,Methylthiophene (1) was treated at 0℃ with liquid bromine to form 3,5,dibromo,2,methylthiophene (2) which reacted with tributyl borate to give 2,methyl,3,bromo,5,boronate thiophene (3) at,78℃. Treatment of 3 with 3,4,difluorobrombenzene gave 2,methyl,3,bromo,5,(3,4,difluorophenyl)thiophene (4). Finally,a novel photochromic dithienylethene compound,1,2,bis [2,methyl,5(3,4,difluorophenyl),3,thienyl]perfluorocyclopentene (DT,1),was synthesized by the reaction of 4 with perfluorocyclopentene at,78℃. The compound (DT,1)was characterized by IR,NMR,MS,elemental analysis and its photochromic behavior was also discussed.

  8. Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

    Science.gov (United States)

    Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E.; Chan, Benny C.; de Lill, Daniel T.

    2015-05-01

    Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C6H2O5)(C6H3O5)(H2O)]n (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented.

  9. Time-resolved laser fluorescence spectroscopy of UO2(CO3)3(4-).

    Science.gov (United States)

    Jung, E C; Cho, H-R; Baik, M H; Kim, H; Cha, W

    2015-11-21

    The objective of the present study is to examine the luminescence characteristics of UO2(CO3)3(4-) in detail using time-resolved laser fluorescence spectroscopy. The peak wavelengths and lifetime of UO2(CO3)3(4-) were determined at room temperature using the two excitation laser wavelengths of 266 and 448 nm. The peak wavelengths in the luminescence spectrum exhibited hypsochromic shifts compared with those of UO2(2+). The lifetime determined from several samples containing various uranium concentrations was 8.9 ± 0.8 ns. Explanations for the hindrance to the observation of the luminescence spectrum of UO2(CO3)3(4-) in previous investigations are discussed. The representative experimental parameters, which might interrupt the measurement of weak luminescence, are the insertion delay time of the detection device, the overlapped luminescence of the background materials and the primary inner filter effect in the sample solution.

  10. CERN diabetes awareness days

    CERN Multimedia

    2005-01-01

    Do you have diabetes without knowing it? Following last year's successful campaign, the CERN Infirmary has organised two further diabetes prevention and screening days on 10th & 11th October 2005 from 9am to 4pm (INFIRMARY, Bldg 57, ground floor) open to everyone working on the CERN site who was unable to participate in 2004. Testing of blood pressure, cholesterol and sugar levels, Body Mass Index, etc. Information - documentation - personal and individual advice. Presence of a dietician from 2 p.m. to 4 p.m. In cooperation with the NOVAE, DSR & AVENANCE restaurants. Diabetes is reaching epidemic proportions in many countries and, if not diagnosed sufficiently early, can be a major cause of blindness, heart and kidney disease, etc. Prevention is possible through screening and life-style changes such as improved dietary habits and regular physical exercise. Diabetes is not a serious condition in itself if diagnosed and treated early enough but it can have very serious consequences if und...

  11. CERN Diabetes Awareness Days

    CERN Multimedia

    2005-01-01

    Do you have diabetes without knowing it? Following last year's successful campaign, the CERN Infirmary has organised two further diabetes prevention and screening days on 10th & 11th October 2005 from 9am to 4pm (INFIRMARY, Bldg 57, ground floor) open to everyone working on the CERN site who was unable to participate in 2004. Testing of blood pressure, cholesterol and sugar levels, Body Mass Index, etc. Information - documentation - personal and individual advice. Presence of a dietician from 2 p.m. to 4 p.m. In cooperation with the NOVAE, DSR & AVENANCE restaurants Diabetes is reaching epidemic proportions in many countries and, if not diagnosed sufficiently early, can be a major cause of blindness and of heart and kidney disease, etc. Prevention is possible through screening and life-style changes such as improved dietary habits and regular physical exercise. Diabetes is not a serious condition in itself if it is diagnosed and treated early enough but it can have very serious consequences...

  12. AAS 227: Day 3

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 3 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Henry Norris Russell Lecture: Viewing the Universe with Infrared Eyes: The Spitzer Space Telescope (by Erika Nesvold)The Henry Norris Russell Award is the highest honor given by the AAS, for a lifetime of eminence in astronomy research. This years award went to Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. Fazio became a leader in gamma ray astronomy before switching mid-career to the study of infrared astronomy, and he gave his award lecture on the latter subject, specifically on the Spitzer Space Telescope, one of the most successful infrared telescopes of all time.Artists rendering of the Spitzer space telescope. [NASA/JPL-Caltech]Spitzer has been operating for more than twelve years, and has resulted in over six thousand papers in refereed journals in that time. The telescope sits in an Earth-trailing orbit around the Sun, and is now farther from the Earth (1.4 AU) than the Earth is from the Sun. Fazio gave the audience a fascinating overview of the science done by Spitzer over more than a decade. One of the most productive areas of research for Spitzer is the study of exoplanets, which hadnt even been discovered when the Spitzer Telescope was first conceived. Spitzers high sensitivity and ability to observe exoplanets over

  13. Printshop open days

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    With new machines, new services and new opening hours, the CERN Printshop has turned over many new leaves at the start of 2013. Come and find out more from 25 to 27 March at the Printshop open days!   The CERN Printshop’s new 8-metre long black and white printer. The CERN Printshop’s new 8-metre long black-and-white printer is a technical marvel. It can produce 160 pages per minute (it prints on both sides in one pass) and can also staple, punch holes, do thermal binding and make A4 or A5 brochures. The new colour printer is more discreet but no less efficient: it churns out 70 A4 or A3 pages per minute. Once they are printed, colour documents can be inserted into the black and white machine to be hole-punched, made into brochures or bound. They can even be mixed in with black-and-white pages and, as if by magic, come out in the right order! Having recently acquired a state-of-the-art large-format printer, the CERN Printshop can now print posters in A2, A1 or A0 format. ...

  14. Two days of films

    CERN Document Server

    2011-01-01

    The Chinese community at CERN and the CERN CineClub, on the occasion of the Chinese New Year, invite everyone to two days of films Thursday 3 February 2011 at 20:30 - CERN Council Chamber Eat drink man woman Directed by Ang LEE (Taiwan, 1994) 122 min. With Sihung Lung, Yu-Wen Wang, Chien-Lien Wu, Kuei-Mei Yang Senior Master Chef Chu lives in a large house in Taipei with his three unmarried daughters, Jia-Jen, a chemistry teacher converted to Christianity, Jia-Chien, an airline executive, and Jia-Ning, a student who also works in a fast food restaurant. Life in the house revolves around the ritual of an elaborate dinner each Sunday, and the love lives of all the family members. Original version Mandarin with English subtitles Friday 4 February 2011 at 19:30 - CERN Council Chamber Adieu, ma concubine Directed by Chen KAIGE (China / Hong Kong, 1993) 171 min. With Leslie Cheung, Fengyi Zhang, Li Gong "Farewell, My Concubine" is a movie with two parallel, intertwined stories. It is the story of two performers in t...

  15. Seven remarkable days

    CERN Multimedia

    This has been a truly remarkable seven days for CERN. Things have moved so fast that it has sometimes been hard to separate fact from fiction – all the more so since facts have often seemed too good to be true. It’s been a week of many firsts. Monday was the first time we’ve had two captured beams in the LHC. It’s the first time the LHC has functioned as a particle accelerator, boosting particles to the highest beam energy so far achieved at CERN. And it’s been a week in which we’ve seen the highest energy proton-proton collisions ever produced at CERN: our last hadron collider, the SPS was a proton-antiproton collider, a technically simpler machine than the LHC. This week’s successes are all the more remarkable precisely because of the complexity of the LHC. Unlike the SPS collider, it is two accelerators not one, making the job of commissioning nearly twice as difficult. I’d like to express my heartfelt thanks and congra...

  16. AAS 227: Day 2

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 2 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Plenary Session: Black Hole Physics with the Event Horizon Telescope (by Susanna Kohler)If anyone needed motivation to wake up early this morning, they got it in the form of Feryal Ozel (University of Arizona) enthralling us all with exciting pictures, videos, and words about black holes and the Event Horizon Telescope. Ozel spoke to a packed room (at 8:30am!) about where the project currently stands, and where its heading in the future.The EHT has pretty much the coolest goal ever: actually image the event horizons of black holes in our universe. The problem is that the largest black hole we can look at (Sgr A*, in the center of our galaxy) has an event horizon size of 50 as. For this kind of resolution roughly equivalent to trying to image a DVD on the Moon! wed need an Earth-sized telescope. EHT has solved this problem by linking telescopes around the world, creating one giant, mm-wavelength effective telescope with a baseline the size of Earth.Besides producing awesome images, the EHT will be able to test properties of black-hole spacetime, the no-hair theorem, and general relativity (GR) in new regimes.Ozel walked us through some of the theory prep work we need to do now in order to get the most science out of the EHT, including devising new

  17. Yersinia enterocolitica palearctica serobiotype O:3/4 - a successful group of emerging zoonotic pathogens

    Directory of Open Access Journals (Sweden)

    Höper Dirk

    2011-07-01

    Full Text Available Abstract Background High-pathogenic Y. enterocolitica ssp. enterocolitica caused several human outbreaks in Northern America. In contrast, low pathogenic Y. enterocolitica ssp. palearctica serobiotype O:3/4 is responsible for sporadic cases worldwide with asymptomatic pigs being the main source of infection. Genomes of three Y. enterocolitica ssp. palearctica serobiotype O:3/4 human isolates (including the completely sequenced Y11 German DSMZ type strain were compared to the high-pathogenic Y. enterocolitica ssp. enterocolitica 8081 O:8/1B to address the peculiarities of the O:3/4 group. Results Most high-pathogenicity-associated determinants of Y. enterocolitica ssp. enterocolitica (like the High-Pathogenicity Island, yts1 type 2 and ysa type 3 secretion systems are absent in Y. enterocolitica ssp. palearctica serobiotype O:3/4 genomes. On the other hand they possess alternative putative virulence and fitness factors, such as a different ysp type 3 secretion system, an RtxA-like and insecticidal toxins, and a N-acetyl-galactosamine (GalNAc PTS system (aga-operon. Horizontal acquisition of two prophages and a tRNA-Asn-associated GIYep-01 genomic island might also influence the Y. enterocolitica ssp. palearctica serobiotype O:3/4 pathoadaptation. We demonstrated recombination activity of the PhiYep-3 prophage and the GIYep-01 island and the ability of the aga-operon to support the growth of the Y. enterocolitica ssp. enterocolitica O:8/1B on GalNAc. Conclusions Y. enterocolitica ssp. palearctica serobiotype O:3/4 experienced a shift to an alternative patchwork of virulence and fitness determinants that might play a significant role in its host pathoadaptation and successful worldwide dissemination.

  18. Nitrative DNA damage and Oct3/4 expression in urinary bladder cancer with Schistosomahaematobium infection

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ning [Faculty of Health Science, Suzuka University of Medical Science, Suzuka, Mie (Japan); Thanan, Raynoo [Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie (Japan); Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan); Kobayashi, Hatasu [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan); Hammam, Olfat; Wishahi, Mohamed; Leithy, Tarek El [Departments of Pathology and Urology, Theodor Bilharz Research Institute, Giza (Egypt); Hiraku, Yusuke [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan); Amro, EL-Karef [Department of Pathology and Matrix Biology, Mie University Graduate School of Medicine, Mie (Japan); Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura (Egypt); Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan); Ohnishi, Shiho [Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie (Japan); Murata, Mariko [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan); Kawanishi, Shosuke, E-mail: kawanisi@suzuka-u.ac.jp [Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie (Japan); Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie (Japan)

    2011-10-22

    Highlights: {yields} Oct3/4-positive cells increase in Schistosoma haematobium (SH)-associated bladder cancer. {yields} iNOS-dependent DNA lesion, 8-nitroguanine, was formed in Oct3/4-positive cells. {yields} 8-Nitroguanine formed in stem-like cells plays a role in SH-induced carcinogenesis. {yields} Mutant stem cells may participate in inflammation-related carcinogenesis. -- Abstract: To investigate whether mutant stem cells participate in inflammation-related carcinogenesis, we performed immunohistochemical analysis to examine nitrative and oxidative DNA lesions (8-nitroguanine and 8-oxodG) and a stem cell marker Oct3/4 in bladder tissues obtained from cystitis and bladder cancer patients infected with Schistosomahaematobium (S. haematobium). We also detected the expression of nuclear factor-{kappa}B (NF-{kappa}B) and inducible nitric oxide synthase (iNOS), which lead to 8-nitroguanine formation. The staining intensity of 8-nitroguanine and 8-oxodG was significantly higher in bladder cancer and cystitis tissues than in normal tissues. iNOS expression was colocalized with NF-{kappa}B in 8-nitroguanine-positive tumor cells from bladder cancer patients. Oct3/4 expression was significantly increased in cells from S. haematobium-associated bladder cancer tissues in comparison to normal bladder and cancer tissues without infection. Oct3/4 was also expressed in epithelial cells of cystitis patients. Moreover, 8-nitroguanine was formed in Oct3/4-positive stem cells in S. haematobium-associated cystitis and cancer tissues. In conclusion, inflammation by S.haematobium infection may increase the number of mutant stem cells, in which iNOS-dependent DNA damage occurs via NF-{kappa}B activation, leading to tumor development.

  19. Sodium samarium tetrakis(polyphosphate), NaSm(PO3)4

    OpenAIRE

    Dan Zhao; Lina Zhang; Feifei Li

    2010-01-01

    NaSm(PO3)4 has been prepared by solid state reactions. It belongs to type II of the structural family of MILnIII(PO3)4 compounds (MI = alkali metal and LnIII = rare earth metal) and is composed of ∞(PO3)n]n− polyphosphate chains with a repeating unit of four PO4 tetrahedra. The chains extend parallel to [100] and share O atoms with irregular SmO8 polyhedra, forming a three-dimensional framework which delimits tunnels occupied by Na+ cations in a distorted octahedral enviro...

  20. Photophysical characterization of 2,3-difunctionalized thieno[3,4-b]pyrazines

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, S.C. E-mail: seth.rasmussen@ndsu.nodak.edu; Sattler, D.J.; Mitchell, K.A.; Maxwell, John

    2004-08-01

    In order to better understand the optical properties of polythieno[3,4-b]pyrazine materials, the photophysical characteristics of a series of monomeric 2,3-difunctionalized thieno[3,4-b]pyrazines (where R=H, CH{sub 3}, C{sub 6}H{sub 13}, C{sub 8}H{sub 17}, C{sub 10}H{sub 21}, C{sub 12}H{sub 25}, and Ph) have been studied. Characterization of the room temperature UV-vis and fluorescence spectra, including solvent and pH dependence, are presented and compared to the related species isothianaphthene and quinoxaline.

  1. Synthesis, characterization, and crystal structure of 2-iodo-3,4,5-trimethoxybenzoic acid

    Science.gov (United States)

    Kolev, Iliyan N.; Petrova, Svetlana P.; Nikolova, Rositsa P.; Dimowa, Louiza T.; Shivachev, Boris L.

    2013-02-01

    This work describes the synthesis of 2-iodo-3,4,5-trimethoxybenzoic acid. The combination of iodine and silver trifluoroacetate (AgTFA) reagents was used successfully for the iodination of 3,4,5-trimetoxybenzoic acid. To improve the efficiency of the synthetic process a significant modification on the experimental design was also performed. The main structural features of the obtained aryl iodide were investigated by a single crystal X-ray diffraction analysis, FTIR, 1H and 13C NMR spectroscopy.

  2. Development of intelligent ECT system for 3/4 inch SG tubes

    International Nuclear Information System (INIS)

    Intelligent ECT system for 7/8 inch tubes has been qualified as official method for inspection of Steam Generator tubes in Japan since 2003. We have developed Intelligent ECT system for 3/4 inch outer diameter tubes, which is applicable for full length inspection of all tubes in Steam Generator. We have carried out the verification test on passage, scanning speed, detectability of various defects performance of auto screening, effectiveness of filtering, and accuracy of depth sizing of wears. Totally we have confirmed the performance of Intelligent ECT system for 3/4 inch tubes is equivalent to that of Intelligent ECT system for 7/8 inch tubes. (author)

  3. Synthesis and biological evaluation of β -aroylpropionic acid based 1,3,4-oxadiazoles

    Directory of Open Access Journals (Sweden)

    Husain A

    2009-01-01

    Full Text Available In the present investigation, two new series, 1-(4-benzylphenyl-3-(5-substituted-1,3,4-oxadiazol-2-yl-1-propanone and 1-(4-ethylphenyl-3-(5-substituted-1,3,4-oxadiazol-2-yl-1-propanone from β-(4-benzylbenzoylpropionic acid and β-(4-ethylbenzoylpropionic acid, respectively, were synthesized and tested for antiinflammatory, analgesic, lipid peroxidation, ulcerogenic and antibacterial actions. A fair number of compounds were found to have good antiinflammatory activity in carrageenan-induced rat paw edema test, while a few compounds showed significant antibacterial activity. The newly synthesized compounds showed very low ulcerogenic action.

  4. 2,3,4,6-Tetrachlorophenyl esters as antiseptics for fibrous materials

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, N.I.; Ryakhovskaya, A.I.; Romanenko, O.A.; Garifullina, K.R.

    1983-09-10

    Wastes containing tri- and tetrachlorobenzenes are obtained during production of di- and trichlorobenzenes. One way of utilizing these wastes is conversion into di- and trichlorophenols by saponification. Chlorination of a mixture of di- and trichlorophenols converts it into 2,3,4,6-tetrachlorophenol with high yields (95-96 wt. %). The uses of tetrachlorophenol are limited by its strong specific odor and volatility. The possibility of obtaining esters of 2,3,4,6-tetrachlorophenol and saturated aliphatic C/sub 2/-C/sub 12/ monocarboxylic acids, which have good antiseptic properties in relation to fibrous materials are described.

  5. Interleukin 2 promotes growth and cytolytic activity in human T3+4-8- thymocytes.

    OpenAIRE

    de la Hera, A; Toribio, M L; Marquez, C; C. Martinez

    1985-01-01

    Human thymocytes bearing T3 but neither T4 nor T8 antigens (T3+4-8- cells) were obtained after negative selection of thymocytes, either fresh or cultured in medium containing recombinant interleukin 2 (IL-2), by treatment with Na1/34, OKT4A and B9.4 monoclonal antibodies (which recognize T6, T4, and T8 antigens, respectively) and complement. Quantitative flow cytometry showed a 98% pure population of T3+4-8- lymphocytes, which included proliferating cells. The growth and maturation requiremen...

  6. Synthesis of 3-{4-[4-(Benzylideneaminobenzenesulfonyl]- phenyl}-2-phenylquinazolin-4(3H-one

    Directory of Open Access Journals (Sweden)

    Sunil Manohar Babu

    2009-01-01

    Full Text Available The present work describes the synthesis of a Schiff base, 3-{4-[4-(benzylideneamino benzenesulfonyl]phenyl}-2-phenylquinazolin-4(3H-one from a novel quinazolinone, 3-[4-(4 aminobenzenesulfonylphenyl]-2-phenylquinazolin-4(3H-one. The quinazolinone was prepared by reacting 2-phenyl-4H-3,1 benzoxazin-4-one with dapsone. The structure of the synthesized Schiff base is confirmed by IR, 1H NMR, 13C NMR, MS and elemental analysis.-

  7. Synthesis and biological evaluation of new pyrazolo[3,4-d]pyrimidine derivatives

    OpenAIRE

    Asma Agrebi; Fatma Allouche; Hamadi Fetoui; Fakher Chabchoub

    2014-01-01

    Several new pyrazolopyrimidine compounds were achieved from aminocyanopyarazole 1. The starting material 1 was initially coupled with orthoester at refluxed with various primary amines, ammonia, hydrazines and hydroxylamine to furnish a series of pyrazolo[3,4-d]pyrimidines. The reaction of imidate 2a-b with hydrazide derivatives led to the formation of pyrazolo[3,4-d][1,2,4]triazolo[4,3-c]pyrimidines. Some of the synthesized compounds 3a and 4c were evaluated for the...

  8. Synthesis and Antitumor Activity of 5,6-2H-[1,2,4]-Triazolo [3,4-b][1,3,4]thiadiazine Derivatives%5,6-2H-1,2,4-三唑[3,4-b][1,3,4]噻二嗪衍生物的合成及抗癌活性测定

    Institute of Scientific and Technical Information of China (English)

    郑玉国; 薛伟; 郭晴晴; 卢平; 王贞超; 袁凯

    2011-01-01

    A series of 4-(substituted-3-phenylideneamino)-3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-5(4H)-thiones (3) were synthesized by the condensation reaction of 4-amino-3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-5(4H)-thione (2) with various substituted benzaldehydes.Alkylation of 3 with alkyl halides afforded [1,2,4]triazolo[3,4-6][1,3,4]thiadiazme derivatives 4.Their structures were confirmed by 1H NMR, 13C NMR, IR spectra and elemental analyses.Preliminary bioassay indicated that some compounds posed antitumor activity to human prostate cancer cell line (PC3) in vitro by microculture tetrazolium (MTT) method.The antiproliferation activity of compound 4a to PC3 cells at the concentration of 10 μmol·L-1 was 75.9%.%取代苯甲醛与4-氨基-5-(3,4,5-三甲氧基苯基)-1,2,4-三唑-3-硫酮(2)缩合生成5-(3,4,5-三甲氧基苯基)-4-取代苯基亚胺基-1,2,4-三唑-3-硫酮(3),再烷基加成化为新型5,6-2H-1,2,4-三唑[3,4-b][1,3,4]噻二嗪衍生物4.化合物结构经1HNMR 13C NMR,IR以及元素分析确认.采用噻唑兰(MTT)比色法进行化合物抑制人体前列腺癌细胞(PC3)体外活性测试,结果表明所合成的化合物具有不同程度的抑制PC3活性,其中化合物4a在10μmol·L-1浓度下对PC3的抑制率为75.9%.

  9. A DAY WITHOUT FAFH IS A DAY WITH BETTER NUTRITION

    OpenAIRE

    Binkley, James K.

    2003-01-01

    Two day food intakes from the continuing Survey of Individual Food Intake is used to compare nutrition of individuals who on one day had a FAFH meal and on the other did not. It is found that nutrition on the FAFH day is consistently worse for almost all population subgroups. In particular, significantly more calories are consumed on a day with FAFH meal.

  10. (±)-3,4-Methylenedioxymethamphetamine treatment in adult rats impairs path integration learning: A comparison of single versus once per week treatment for five weeks

    OpenAIRE

    Skelton, Matthew R.; Able, Jessica A.; Grace, Curtis E.; Herring, Nicole R.; Schaefer, Tori L.; Gudelsky, Gary A.; Vorhees, Charles V.; Williams, Michael T

    2008-01-01

    3,4-Methlylenedioxymethamphetamine (MDMA) administration (4 × 15 mg/kg) on a single day has been shown to cause path integration deficits in rats. While most animal experiments focus on single binge-type models of MDMA use, many MDMA users take the drug on a recurring basis. The purpose of this study was to compare the effects of repeated single-day treatments with MDMA (4 × 15 mg/kg) once weekly for 5 weeks to animals that only received MDMA on week-5 and saline on weeks 1–4. In animals trea...

  11. International Women's Day speech.

    Science.gov (United States)

    Kazibwe, S W

    1993-01-01

    The objectives of the International Women's Day are: 1) to celebrate the struggle for women's rights in the economic, social, political, and cultural domain; 2) to reaffirm women's solidarity in the struggle for peace; 3) and to show what women have achieved. In 1988, Uganda's government of the National Resistance Movement created the Ministry of Women in Development. The period 1988-1990 was one of consultations, needs assessment, planning, and recruiting staff for the Ministry. From 1990 to 1993, measurable results have been achieved. The Ministry's gender concerns pertained to the sector policies of the Ministries of Agriculture, Animal Industry and Fisheries, Education, Health, Water, Energy, Minerals, and Environment Protection. Under the Umbrella Project for Women in Development, gender sensitization has been achieved with policy makers in ministries, at district level, and in the media. Gender issues have also been incorporated in the National Political School Curriculum. The Ministry has also trained a corps of 73 women trainers from 38 districts. The Ministry, with funding from DANIDA, collected women's views on the constitution through meetings and seminars in all the districts in the country. Recommendations were submitted in a consolidated report to the Constitution Commission. A pilot para-legal scheme is successfully being implemented in Kamuli district. A community-based pool of legal advisors has been developed. Legal matters that affect both women and men are undertaken at the community level. The economic emancipation of women is a crucial part of the Ministry's mandate. In conjunction with NGOs, pilot credit programs are being run in Mukono, Jinja, Mbale, and Kapchorwa districts. Cross-sectoral programs are in close collaboration with the rural water and sanitation program, the Northern Uganda rehabilitation program, and the integrated Basic Education Pilot Project to be implemented in 8 districts. PMID:12345405

  12. AAS 227: Day 3

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 3 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Henry Norris Russell Lecture: Viewing the Universe with Infrared Eyes: The Spitzer Space Telescope (by Erika Nesvold)The Henry Norris Russell Award is the highest honor given by the AAS, for a lifetime of eminence in astronomy research. This years award went to Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. Fazio became a leader in gamma ray astronomy before switching mid-career to the study of infrared astronomy, and he gave his award lecture on the latter subject, specifically on the Spitzer Space Telescope, one of the most successful infrared telescopes of all time.Artists rendering of the Spitzer space telescope. [NASA/JPL-Caltech]Spitzer has been operating for more than twelve years, and has resulted in over six thousand papers in refereed journals in that time. The telescope sits in an Earth-trailing orbit around the Sun, and is now farther from the Earth (1.4 AU) than the Earth is from the Sun. Fazio gave the audience a fascinating overview of the science done by Spitzer over more than a decade. One of the most productive areas of research for Spitzer is the study of exoplanets, which hadnt even been discovered when the Spitzer Telescope was first conceived. Spitzers high sensitivity and ability to observe exoplanets over

  13. Tritium conference days

    International Nuclear Information System (INIS)

    This document gathers the slides of the available presentations given during this conference day. Twenty presentations out of 21 are assembled in the document and deal with: 1 - tritium in the environment (J. Garnier-Laplace); 2 - status of knowledge about tritium impact on health (L. Lebaron-Jacobs); 3 - tritium, discrete but present everywhere (M. Sene); 4 - management of tritium effluents from Areva NC La Hague site - related impact and monitoring (P. Devin); 5 - tritium effluents and impact in the vicinity of EDF's power plants (V. Chretien and B. Le Guen); 6 - contribution of CEA-Valduc centre monitoring to the knowledge of atmospheric tritiated water transfers to the different compartments of the environment (P. Guetat); 7 - tritium analysis in environment samples: constraints and means (N. Baglan); 8 - organically-linked tritium: the analyst view (E. Ansoborlo); 9 - study of tritium transfers to plants via OBT/HTOair and OBT/HTOfree (C. Boyer); 10 - tritium in the British Channel (M. Masson and P. Bailly-Du-Bois); 11 - tritium in British coastal waters (S. Jenkinson); 12 - recent results from epidemiology (R. Wakeford); 13 - effects of tritiated thymidine on hematopoietic stem cells (P.H. Romeo); 14 - tritium management issue in Canada: the point of view from authorities (P. Thompson); 15 - experience feedback of the detritiation process of Valduc centre (D. Leterq); 16 - difficulties linked with tritiated wastes confinement (F. Chastagner); 17 - optimisation of tritium management in the ITER project (P. Cortes); 18 - elements of thought about the management of tritium generated by nuclear facilities (M. Philippe); 19 - CIPR's position about the calculation of doses and risks linked with tritium exposure (F. Paquet); 20 - tritium think tanks (M. Fournier). (J.S.)

  14. Superconducting Tunnel Junction Refrigerators for Sub-Kelvin Cooling of Electrons, Phonons, and Arbitrary, User-Supplied Payloads

    Science.gov (United States)

    Lowell, Peter Joseph

    Modern science often requires measurements at sub-Kelvin temperatures. Temperatures of 300 mK can be reached by using liquid 3He, but reaching lower temperatures requires the use of adiabatic demagnetization and dilution refrigerators which are complex, large, and costly. Normal-metalInsulatorSuperconductor (NIS) tunnel junctions provide an alternative refrigeration method that is simple to use, compact, and provides continuous cooling power that has the potential to expand the accessibility of these sub-Kelvin temperatures. When properly biased, the electron system in the normal metal of an NIS junction is cooled since the hottest electrons preferentially tunnel from the normal metal to the superconductor, transferring heat in the process. When the normal metal is extended onto a thermally isolated membrane, the cold electrons cool the phonons in the membrane through electron-phonon coupling. In previous work, NIS junctions have been used to cool detectors and bulk objects that were integrated with the membrane, but could not be considered a general-purpose refrigerator since they could not cool arbitrary objects. The goal of this work has been to demonstrate a general-purpose NIS refrigerator to which a user can attach arbitrary bulk objects. First, we discuss NIS refrigeration and then develop a model to predict phonon cooling. We fabricated and tested NIS refrigerators capable of cooling bulk objects and used the model to explain the results. The devices were able to cool phonons from 300 mK to 154 mK with 100 pW of cooling power at 200 mK. With these devices, we were able to cool a 2 cm3 piece of copper from 290 mK to 256 mK with 700 pW of cooling power at 290 mK. This demonstration marks the emergence of NIS refrigerators as a true, general-purpose refrigerator since users can attach arbitrary objects. Measurements of Andreev reflections in the devices and next-generation refrigerators that cool electrons from 100 mK to below 50 mK are also presented.

  15. ESTUDO DA INSTABILIDADE KELVIN-HELMHOLTZ ATRAVÉS DE SIMULAÇÕES COM O CÓDIGO ATHENA

    Directory of Open Access Journals (Sweden)

    Priscila Freitas-Lemes

    2013-12-01

    Full Text Available As instabilidades Kelvin-Helmholtz são comuns em sistemas astrofísicos e vão desde jatos deburacos negros até disco de acreção protoplantário. Um objeto astrofísico com fortes características da instabilidade de Kelvin-Helmholtz é a Nebulosa de Caraguejo, na qual a expansão do material foi ocasionado pela explosão de uma supernova há, aproximadamente, 1000 anos. Essa instabilidade ocorre no limite entre dois fluidos de diferentes densidades, quando um dos fluidos é acelerado com relação ao outro. Com o objetivo de estudar essa instabilidade, realizamos uma simulação com o código de malha euleriana ATHENA. Para essasimulação, consideramos um domínio quadrado com limites periódicos sobre as laterais, e, refletindo na fronteirada parte superior e inferior. A região superior da caixa é preenchida com um gás de densidade ρ=1,0, pressãoP1=1,0, índice adiabático γ=5/3 e velocidade u1=0,03 na direção x (para direita. A parte inferior tem densidadeρ=2,0, mesma pressão, velocidade e índice adiabático, só que no sentido contrário, para a esquerda. A velocidade é definida como uma função senoidal, que cria a perturbação inicial. Como resultado, observamos o princípio da instabilidade e a formação dos vórtices, com as cristas bem definidas. A nitidez da fronteira entre o material de alta e de baixa densidade está bem conservada, devido à difusão relativamente baixa do algoritmo. Notamos, ainda, que, evoluindo a simulação, os vórtices formados a partir da turbulência fundem-se.

  16. Sequential afterglow processing and non-contact Corona-Kelvin metrology of 4H-silicon carbide

    Science.gov (United States)

    Short, Eugene L., III

    Silicon carbide (SiC) is a wide band-gap semiconductor with advantageous electrical and thermal properties making it attractive for high temperature and power applications. However, difficulties with oxide/SiC structures have posed challenges to the development of practical MOS-type devices. Surface conditioning and oxidation of 4H-SiC were investigated using a novel sequential afterglow processing approach combined with the unique capabilities of non-contact corona-Kelvin metrology. The use of remote plasma assisted thermal oxidation facilitated film growth at low temperature and pressure with the flexibility of sequential in-situ processing options including pre-oxidation surface conditioning. Corona-Kelvin metrology (C-KM) provided a fast, nondestructive method for electrical evaluation of oxide films and semiconductor surfaces. Non-contact C-KM oxide capacitance-voltage characteristics combined with direct measurement of SiC surfaces using C-KM depletion surface barrier monitoring and XPS analysis of surface chemistry were interpreted relating the impact of afterglow conditioning on the surface and its influence on subsequent oxide thin film growth. Afterglow oxide films of thicknesses 50--500 A were fabricated on SiC epi-layers at low growth temperatures in the range 600--850°C, an achievement not possible using conventional atmospheric oxidation techniques. The inclusion of pre-oxidation surface conditioning in forming gas (N2:H2)* afterglow was found to produce an increase in oxide growth rate (10--25%) and a significant improvement in oxide film thickness uniformity. Analysis of depletion voltage transients on conditioned SiC surfaces revealed the highest degree of surface passivation, uniformity, and elimination of sources of charge compensation accomplished by the (N2:H2)* afterglow treatment for 20 min. at 600--700°C compared to other conditioning variations. The state of surface passivation was determined to be very stable and resilient when exposed

  17. Highly conductive poly(3,4-ethylenedioxypyrrole) and poly(3,4-ethylenedioxythiophene) enwrapped Sb2S3 nanorods for flexible supercapacitors.

    Science.gov (United States)

    Reddy, B Narsimha; Deepa, Melepurath; Joshi, Amish G

    2014-02-01

    Composites of poly(3,4-ethylenedioxypyrrole) or PEDOP and poly(3,4-ethylenedioxythiophene) or PEDOT enwrapped Sb2S3 nanorods have been synthesized for the first time for use as supercapacitor electrodes. Hydrothermally synthesized Sb2S3 nanorods, several microns in length and 50-150 nm wide, offer high surface area and serve as a scaffold for coating conducting polymers, and are a viable alternative to carbon nanostructures. Fibrillar morphologies are achieved for the PEDOP-Sb2S3 and PEDOT-Sb2S3 films in contrast to the regular granular topologies attained for the neat polymers. The remarkably high nanoscale (∼5 S cm(-1)) conductivity of the Sb2S3 nanorods enables facile electron transport in the composites. We constructed asymmetric supercapacitors using the neat polymer or composite and graphite as electrodes. High specific capacitances of 1008 F g(-1) and 830 F g(-1) (at 1 A g(-1)), enhanced power densities (504 and 415 W kg(-1)) and excellent cycling stability (88 and 85% capacitance retention at the end of 1000 cycles) are delivered by the PEDOP-Sb2S3 and PEDOT-Sb2S3 cells relative to the neat polymer cells. A demonstration of a light emitting diode illumination using a light-weight, flexible, supercapacitor fabricated with PEDOP-Sb2S3 and carbon-fiber cloth shows the applicability of Sb2S3 enwrapped conducting polymers as sustainable electrodes for ultra-thin supercapacitors. PMID:24343566

  18. Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite based thin films for Schottky diode application

    International Nuclear Information System (INIS)

    Transparent, conductive films of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite were synthesized by in-situ oxidative polymerization and investigated for their Schottky diode property. The prepared films were characterized by UV–Vis spectroscopy, thermal gravimetric analysis (TGA), surface resistivity, cyclic voltametery, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). SEM reveals the formation of homogeneous and adhesive polymer films while HRTEM confirms the uniform wrapping of polymer chains around the nanotube walls for PEDOT-FWCNT film. Improved thermal stability, conductivity and charge storage property of PEDOT in the presence of FWCNT is observed. Among different compositions, 5 wt. % of FWCNT is found to be optimum with sheet resistance and transmittance of 500 Ω sq−1 and 77%, respectively. Moreover, the electronic and junction properties of polymer films were studied and compared by fabricating sandwich type devices with a configuration of Al/PEDOT or PEDOT-FWCNT nanocomposite/indium tin oxide (ITO) coated glass. The measured current density-voltage characteristics show typical rectifying behavior for both configurations. However, enhanced rectification ratio and higher forward current density is observed in case of PEDOT-FWCNT based Schottky diode. Furthermore, reliability test depicts smaller hysteresis effect and better performance of PEDOT-FWCNT based diodes. - Highlights: • Single step synthesis of PEDOT and PEDOT-FWCNT nanocomposites films via in-situ oxidative polymerization. • Thermal, electrical and electrochemical properties of films show positive effect of FWCNT on PEDOT films. • Schottky diodes based on metal Al/PEDOT or PEDOT-FWCNT composites/ITO glass are fabricated. • Improved electrical characteristics with better reliability is achieved for PEDOT-FWCNT based diodes

  19. Methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxypyrovalerone (MDPV) induce differential cytotoxic effects in bovine brain microvessel endothelial cells.

    Science.gov (United States)

    Rosas-Hernandez, Hector; Cuevas, Elvis; Lantz, Susan M; Rice, Kenner C; Gannon, Brenda M; Fantegrossi, William E; Gonzalez, Carmen; Paule, Merle G; Ali, Syed F

    2016-08-26

    Designer drugs such as synthetic psychostimulants are indicative of a worldwide problem of drug abuse and addiction. In addition to methamphetamine (METH), these drugs include 3,4-methylenedioxy-methamphetamine (MDMA) and commercial preparations of synthetic cathinones including 3,4-methylenedioxypyrovalerone (MDPV), typically referred to as "bath salts." These psychostimulants exert neurotoxic effects by altering monoamine systems in the brain. Additionally, METH and MDMA adversely affect the integrity of the blood-brain barrier (BBB): there are no current reports on the effects of MDPV on the BBB. The aim of this study was to compare the effects of METH, MDMA and MDPV on bovine brain microvessel endothelial cells (bBMVECs), an accepted in vitro model of the BBB. Confluent bBMVEC monolayers were treated with METH, MDMA and MDPV (0.5mM-2.5mM) for 24h. METH and MDMA increased lactate dehydrogenase release only at the highest concentration (2.5mM), whereas MDPV induced cytotoxicity at all concentrations. MDMA and METH decreased cellular proliferation only at 2.5mM, with similar effects observed after MDPV exposures starting at 1mM. Only MDPV increased reactive oxygen species production at all concentrations tested whereas all 3 drugs increased nitric oxide production. Morphological analysis revealed different patterns of compound-induced cell damage. METH induced vacuole formation at 1mM and disruption of the monolayer at 2.5mM. MDMA induced disruption of the endothelial monolayer from 1mM without vacuolization. On the other hand, MDPV induced monolayer disruption at doses ≥0.5mM without vacuole formation; at 2.5mM, the few remaining cells lacked endothelial morphology. These data suggest that even though these synthetic psychostimulants alter monoaminergic systems, they each induce BBB toxicity by different mechanisms with MDPV being the most toxic. PMID:27320055

  20. AAS 227: Day 2

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 2 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Plenary Session: Black Hole Physics with the Event Horizon Telescope (by Susanna Kohler)If anyone needed motivation to wake up early this morning, they got it in the form of Feryal Ozel (University of Arizona) enthralling us all with exciting pictures, videos, and words about black holes and the Event Horizon Telescope. Ozel spoke to a packed room (at 8:30am!) about where the project currently stands, and where its heading in the future.The EHT has pretty much the coolest goal ever: actually image the event horizons of black holes in our universe. The problem is that the largest black hole we can look at (Sgr A*, in the center of our galaxy) has an event horizon size of 50 as. For this kind of resolution roughly equivalent to trying to image a DVD on the Moon! wed need an Earth-sized telescope. EHT has solved this problem by linking telescopes around the world, creating one giant, mm-wavelength effective telescope with a baseline the size of Earth.Besides producing awesome images, the EHT will be able to test properties of black-hole spacetime, the no-hair theorem, and general relativity (GR) in new regimes.Ozel walked us through some of the theory prep work we need to do now in order to get the most science out of the EHT, including devising new

  1. 2016 SPD: Day 1

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    Editors note: This week were in Boulder, Colorado at the 47th meeting of the AAS Solar Physics Division (SPD). Follow along to catch some of the latest news from the field of solar physics!The 2016 SPD meeting was launched this morning from the University of Colorado Boulder campus. Two of the hot topics at this years meeting include celebration of the recent move of the National Solar Observatorys headquarters to Boulder, and discussion of the future Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST). DKIST, planned for a 2019 completion in Hawaii, is the next big telescope on the horizon for solar physics.Todays press conference had an interesting focus: instruments providing new high-energy observations of the Sun. Representatives from four different instruments were here to talk about some of the latest X-ray solar observations.GRIPSThe GRIPS payload flew at 130,000 ft over Antarctica on a giant balloon in January 2016. [NASA/Albert Shih]First up, Albert Shih (NASA Goddard) described the Gamma-Ray Imager/Polarimeter for Solar flares, or GRIPS. GRIPS is a balloon-borne instrument designed to detect X-rays and gamma rays emitted during solar flares. Up to tens of a percent of the energy in solar flares is emitted in the form of accelerated particles, but the physics behind this process is not well understood. GRIPS observes where the highest-energy particles are accelerated, in an effort to learn more about the process.GRIPS was launched on 19 January, 2016 and flew for roughly 12 days gathering ~1 million seconds of data! The logistics of this instruments flight are especially interesting, since it was launched from Antarctica and carried by a balloon at a whopping elevation of 130,000 ft (to get high enough that the atmosphere doesnt absorb all the photons GRIPS is trying to observe). Though the data from the mission has been retrieved, the bulk of the hardware remains where it landed at the end of January. It must

  2. Preparation and Luminescence Characteristics of Ca3Y2(BO3)4:Eu3+ Phosphor

    Institute of Scientific and Technical Information of China (English)

    LI Pan-Lai; YANG Zhi-Ping; WANG Zhi-Jun; Guo Qing-Lin

    2007-01-01

    Ca3Y2(BO3)4:Eu3+ phosphor is synthesized by high temperature solid-state reaction method, and the luminescence characteristics are investigated. The emission spectrum exhibits two strong red emissions at 613 and 621 nm corresponding to the electric dipole 5 Do-7F2 transition of Eu3+ under 365 nm excitation, the reason is that Eu3+ substituting for y3+ occupies the non-centrosymmetric position in the crystal structure of Ca3Y2 (BO3 )4. The excitation spectrum for 613 nm indicates that the phosphor can be effectively excited by ultraviolet (UV) (254 nm,365nm and 400nm) and blue (470nm) light. The effect of Eu3+ concentration on the emission intensity of Ca3Y2 (BO3 )4:Eu3+ phosphor is measured, the result shows that the emission intensities increase with increasing Eu3+ concentration, then decrease. The CIE colour coordinates of Ca3Y2(BO3)4:Eu3+ phosphor is (0.639, 0.357) at 15mol% Eu3+.

  3. Ethanol co-administration moderates 3,4-methylenedioxymethamphetamine effects on human physiology

    NARCIS (Netherlands)

    Dumont, G.J.H.; Kramers, C.; Sweep, F.C.G.J.; Willemsen, J.J.; Touw, D.J.; Schoemaker, R.C.; Van Gerven, J.M.A.; Buitelaar, J.K.; Verkes, R.J.

    2010-01-01

    Alcohol is frequently used in combination with 3,4- methylenedioxymethamphetamine (MDMA). Both drugs affect cardiovascular function, hydration and temperature regulation, but may have partly opposing effects. The present study aims to assess the acute physiologic effects of (co-) administration of M

  4. Increased oxytocin concentrations and prosocial feelings in humans after ecstasy (3,4-methylenedioxymethamphetamine) administration

    NARCIS (Netherlands)

    Dumont, G J H; Sweep, F C G J; van der Steen, R; Hermsen, R; Donders, A R T; Touw, D J; van Gerven, J M A; Buitelaar, J K; Verkes, R J

    2009-01-01

    MDMA (3,4-methylenedioxymethamphetamine or "ecstasy") is a recreationally used drug with remarkable and characteristic prosocial effects. In spite of abundant attention in the scientific literature, the mechanism of its prosocial effects has not been elucidated in humans. Recently, research in anima

  5. 39 CFR 3.4 - Matters reserved for decision by the Governors.

    Science.gov (United States)

    2010-07-01

    ... SERVICE BOARD OF GOVERNORS (ARTICLE III) § 3.4 Matters reserved for decision by the Governors. The...) Appointment and removal of the Inspector General under 39 U.S.C. 202(e). (j) Exercise of the authority of the... research special postage stamp under 39 U.S.C. 414 and any semipostal stamp under 39 U.S.C. 416....

  6. Synthesis and antifungal activity of natural product-based 6-alkyl-2 3 4 5-tetrahydropyridines

    Science.gov (United States)

    Seven 6-alkyl-2,3,4,5-tetrahydropyridines (5a–5g) that mimic the natural products piperideines that were recently identified in the fire ant venom have been synthesized. Compounds 5c–5g with the C-6 alkyl chain lengths from C14 to C18 showed varying degrees of antifungal activities, with 5e (6-hexa...

  7. Biocatalytic acylation of sugar alcohols by 3-(4-hydroxyphenyl)propionic acid

    NARCIS (Netherlands)

    Croitoru, R.; Fitigau, F.; Broek, van den L.A.M.; Frissen, A.E.; Boeriu, C.G.

    2012-01-01

    Enzymatic synthesis of aromatic esters of four different sugar alcohols (xylitol, arabitol, mannitol, and sorbitol) with 3-(4-hydroxyphenyl)propionic acid was performed in organic solvent medium, using immobilized Candida antarctica lipase (Novozyme 435), and molecular sieves for control of the wate

  8. Schisanlactone G,a new 3,4-seco-lanostane triterpenoid from Schisandra sphenanthera

    Institute of Scientific and Technical Information of China (English)

    Rong Ren; Guo Jun Luo; Hong Mei Li; Zhao Yuan Wu; Hai Zhou Li; Rong Tao Li

    2009-01-01

    A new 3,4-seco-lanostane triterpenoid,schisanlactone G (1),was isolated from the fruits of Schisandra sphenanthera.Its structure was established on the basis of extensive spectroscopic analysis.2009 Rong Tao Li.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All fights reserved.

  9. Virginia Tech gets $3.4 million for Gulf oil spill study on plovers

    OpenAIRE

    Davis, Lynn

    2010-01-01

    Researchers from Virginia Tech's College of Natural Resources and Environment have received a $3.4 million grant from the U.S. Department of the Interior to study the effects of the Deepwater Horizon oil spill in the Gulf of Mexico on piping plovers.

  10. SAC on a Niagara T3-4 Server: Lessons and Experiences

    NARCIS (Netherlands)

    C. Grelck; R. Douma

    2011-01-01

    The Sparc T3-4 server provides up to 512 concurrent hardware threads, a degree of concurrency that is unprecedented in a single server system. This paper reports on how the automatically parallelising compiler of the data-parallel functional array language SAC copes with up to 512 execution units. W

  11. Synthesis of novel pyrazolo[3,4-d]pyrimidinone derivatives as cytotoxic inhibitors

    Directory of Open Access Journals (Sweden)

    Ameur Rahmouni

    2014-02-01

    Full Text Available Various α-fonctionalized iminoethers 2 were easily prepared from ethyl 5-amino-3-substituted-1-phenyl-1H-pyrazole-4-carboxylate 1. The reaction of iminoethers 2 with ammonia afforded 3-substitued-1-phenyl-1H-pyrazolo[3,4-d] pyrimidin-4(5H-ones 3 which were also synthesized by the addition of formamide to ethyl 5-amino-3-substituted-1-phenyl-1H-pyrazole-4-carboxylate 1. The 5-amino-3-substitued-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H-ones 4 were obtained from hydrazonolysis of iminoethers 2. Otherwise, the condensation of these intermediates 2 with a series of some primary amines and hydroxylamine led respectively, to the corresponding 3,5-disubstitued-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H-ones 5 and the 3-substitued-5-hydroxy-1-phenyl-1H-pyrazolo[3,4-d] pyrimidin-4-(5H-ones 6. The synthesized compounds 1-6 were completely characterized by 1H NMR, 13C NMR, IR and HRMS. Some synthesized compounds were evaluated for their cytotoxic effect using the Human cervical adenocarcinoma Hela cell line.

  12. Pharmacological Studies of p, N-(3, 4-Methylenedioxy phenyl Benzoic Acid (RRL-1364 - Part-I

    Directory of Open Access Journals (Sweden)

    Dahanukar Sharadini

    1978-01-01

    Full Text Available Detailed pharmacological investigations of p-N-(3, 4-methylene dioxy phenyl benzoic acid revealed marked hypotensive action which was dose dependent and most marked in cats; it was absent in rats. Atropine could block this hypotensive action, thus suggest-ing cholinomimetic mechanism. Further studies indicated that the hypotension produced was central and possibly medullary in origin.

  13. 1-(4-Chlorophenyl-3-(3,4-dimethylphenylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Meng Guo

    2010-09-01

    Full Text Available The title compound, C17H15ClO, was prepared from 3,4-dimethylbenzaldehyde and 4-chlorohypnone by Aldol condensation. The dihedral angle formed by the two benzene rings is 48.91 (8°. Only van der Waals forces affect the packing.

  14. 1-(4-Chlorophenyl)-3-(3,4-dimethylphenyl)prop-2-en-1-one

    OpenAIRE

    Meng Guo

    2010-01-01

    The title compound, C17H15ClO, was prepared from 3,4-dimethylbenzaldehyde and 4-chlorohypnone by Aldol condensation. The dihedral angle formed by the two benzene rings is 48.91 (8)°. Only van der Waals forces affect the packing.

  15. QSAR analysis of antitumor activities of 3,4-ethylenedioxythiphene derivatives

    Science.gov (United States)

    Rastija, Vesna; Bajić, Miroslav; Stolić, Ivana; Krstulović, Luka; Jukić, Marijana; Glavaš-Obrovac, Ljubica

    2015-12-01

    QSAR analysis was performed for the antitumor activity of 27 derivatives of 3,4-ethylenedioxythiophene against six carcinoma cell lines. The best models were obtained with surface area (SAG) in combination with lipohilicity (log P) as descriptors. Results have shown that molecules with smaller solvent accessible surface area and higher lipophilicy should have higher biological activity against carcinoma cell.

  16. Treatment Implications for Young Adult Users of MDMA (3,4-Methylenedyoxymethamphetamine)

    Science.gov (United States)

    Dew, Brian J.; Elifson, Kirk W.; Sterk, Claire E.

    2006-01-01

    Young adults' 3,4-methylenedyoxymethamphetamine (MDMA) use is a national public health concern. Although research on the epidemiology of MDMA use has increased, inquiry into intervention and treatment is needed. The authors examine results from an epidemiological investigation from a clinical perspective and provide suggestions for clinicians…

  17. Synthesis of 3-Phenyl-6-formyl-3,4-dihydro-2H-1,3-benzoxazine

    Institute of Scientific and Technical Information of China (English)

    Qi Chao RAN; Qiao TIAN; Yi GU

    2006-01-01

    A novel benzoxazine monomer containing aldehyde group, 3-phenyl-6-formyl-3,4-dihydro-2H-1, 3-benzoxazine (Ald-B), was synthesized via the Mannich condensation of formaldehyde, p-hydroxybenzaldehyde and aniline. Its structure was characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1HNMR). The side reaction in the synthesis is discussed.

  18. 2016 SPD: Day 2

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    advances in simulating sunspot formation. He and his collaborators have used high-performance computing to build a model that successfully reproduces many of the key properties of sunspots that are observed.In particular, these simulations track the motions of the magnetic field starting within the interior of the Sun (8000 km below the surface!). The magnetic field is generated and intensified by convection deep within the solar interior. Bundles of magnetic field then rise through the convection zone, eventually breaking through the solar surface and giving rise to sunspots.This process of tracking the flow as it travels from the convective layer all the way through the solar surface has resulted in what may be some of the highest fidelity simulations of sunspots thus far. The structures produced in these simulations compares very favorably with actual observations of sunspots including the asymmetry seen in most sunspots.Counting Spots on the SunContinuing the discussion of sunspots, Leif Svalgaard (Stanford University) next took us on a historical journey from the 1600s through the present. For the last 400 years starting with Galileo people have kept records of the number of sunspots visible on the Suns disk.One of Galileos drawings of his sunspot observations from 1612. [The Galileo Project]This turns out to be a very useful practice! Total solar irradiance, a measure used as input into climate models, is reconstructed from sunspot numbers. Therefore, the historical record of sunspots over the last 400 years impacts our estimates of the long-term trends in solar activity.Based on raw sunspot counts, studies have argued that solar activity has been steadily increasing over time. But could this be a misinterpretation resulting from the fact that our technology and therefore our ability to detect sunspots has improved over time? Svalgaard believes so.By studying and reconstructing 18th century telescopes, he demonstrates that modern-day sunspot counts are able to detect

  19. AAS 228: Day 4

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    Editors Note: Lastweek we were at the 228th AAS Meeting in San Diego, CA. Here is a final post aboutselectedevents on the last day of the meeting, written by authors fromastrobites.com, a grad-student collaborative project with which we recently announced a new partnership! Starting in July,keep an eye out for astrobites postsat AAS Nova in between Highlights(i.e., on Tuesdays and Thursdays).Were excited to be working together to bring you more recent astronomy research from AAS journals!Extrasolar Planets: Detection (by Leonardo dos Santos)Thursdays first session on exoplanets was about detecting these distant worlds, and the opening talk was given by Robert Siverd (Las Cumbres Observatory). He describes the NRES, a network of spectrographs that will look for exoplanets using the radial velocity method. One of the coolest aspects of this instrument is that it will feature an on the fly scheduling system that will perform observations as efficiently as possible. The spectrograph is still being tested, but a unit will be deployed at CTIO later this year.@lcogt contracted by @NASA_TESS for follow up of their candidates. #aas228 Jessie Christiansen (@aussiastronomer) June 16, 2016Measuring the depths of transits and eclipses in Spitzer has been problematic in the past, since the Spitzer instrument IRAC (InfraRed Array Camera) has a non-uniform response in its detectors pixels. But, as reported by James Ingalls (Spitzer Science Center, Caltech), observers are circumventing this issue by using what they call the staring mode (avoiding large pointing jumps) and an algorithm to pick sweet spot pixels. Moreover, the results from the IRAC Data Challenge are helping to better understand its behavior. Giuseppe Morello (University College London), on the other hand, explained how his research group gets rid of instrumental effects from IRAC using machine learning. This method removes systematics from exoplanet transit data no matter if the noise source is from an instrument or

  20. 2016 SPD: Day 3

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    last the longest 2 minutes and 40 seconds is the small town of Hopkinsville, KY. WKU is located a little over an hour away, and both locations are prepared for a large influx of people on eclipse day!Partial solar eclipse as viewed by the space-based Solar Dynamics Observatory. [NASA/SDO]WKU is located just off the centerline of eclipse path, which has some advantages: this provides better viewing of some of the chromospheric features of the Sun during the eclipse, like priminences and solar loops. WKU is setting up a variety of educational and public outreach activities at their football stadium and the WKU farm, and they encourage you to come visit for the eclipse!In addition, they are participating in a nationwide experiment called Citizen CATE, short for the Continental American Telescopic Eclipse. This project will use 60 telescopes spanning the 2500 mile path of totality to record continuous data of the eclipse as it travels across the US. The result will be data of a remarkable 90 minutes of totality, revealing the activity of the solar corona and providing an extended view of the eclipse as has never been seen before.Science During the EclipseNext up was Shadia Habbal (University of Hawaii), who is a co-leader of the AAS 2017 Eclipse Task Force. In addition to her education and outreach efforts associated with the eclipse, however, Habbal is a solar eclipse researcher. She and her collaborators are known as the Solar Wind Sherpas, due to the fact that they hand-carry their science equipment around the world for solar eclipses!Solar corona during a 2008 eclipse, with color overlay indicating emission from highly ionized iron lines. [Habbal et al. 2010]The primary science done during solar eclipses is the study of the solar corona, the region that extends from the solar surface out to several solar radii. This region is too faint to observe normally, but when the light from the Suns disk is blocked out, we can examine it.Unfortunately, the space telescopes that

  1. Stability of 3,4-methylenedioxymethampetamine (MDMA), 4-methylmethcathinone (mephedrone) and 3-trifluromethylphenylpiperazine (3-TFMPP) in formalin solution.

    Science.gov (United States)

    Maskell, Peter D; Seetohul, L Nitin; Livingstone, Alison C; Cockburn, Alexandra K; Preece, Jamie; Pounder, Derrick J

    2013-09-01

    Occasionally, the only postmortem samples available for analysis are contaminated with formaldehyde, either due to embalming prior to sampling or because analysis is carried out only when formalin-fixed tissues retained for histological study are available. Formaldehyde reacts with several drugs of forensic interest that contain either a primary or a secondary amine group to form their N-methyl derivatives. We investigated the stability of 3,4-methylenedioxymethampetamine (MDMA), 4-methylmethcathinone (mephedrone) and 3-trifluromethylphenylpiperazine (3-TFMPP) in formalin solutions using three different formaldehyde concentrations (5, 10 and 20%) and three different pHs (3.0, 7.0 and 9.5). Analysis was performed using high-performance liquid chromatography with diode array detection to determine the percentage degradation of each drug over time, up to 60 days. MDMA, mephedrone and 3-TFMPP are unstable in formalin solutions, with the degradation rate increasing with increasing pH. After 28 days in 20% formalin, pH 9.5, there remained 57% of the initial 3-TFMPP concentration, 11% of the initial MDMA concentration and 4% of the initial mephedrone concentration. Forensic toxicologists should be aware that, when analyzing for these drugs in an embalmed body or in tissues stored in formalin solutions, the methylated form of the secondary amine-containing drug could be a more useful analyte than the parent drug.

  2. Review of Kelvin's Equation and Its Modification in Characterization of Mesoporous Materials%用于测定介孔的Kelvin方程及其修正述评

    Institute of Scientific and Technical Information of China (English)

    张颖; 阎子峰; 胡喜军

    2006-01-01

    Physical and mathematical models as well as calculation methods of nitrogen bed on porous media have been introduced to evaluate the structural parameters of mesoporous materials. Kelvin's equation is a link between the relative adsorbate pressure, the mean pore radius, and pore capillarity on the basis of macroscopic capillary condensation. However, Kelvin's equation has been identified that it underestimates the calculated pore size of a material especially in the boundary of pore size which is between 2 and 4 nm.Various modifications on Kelvin's equation were mentioned in order to develop a new model to improve the accuracy of pore size calculation. The problems on conventional mathematical models were analyzed and discussed. A number of calculation methods on physisorption and pore size, especially fundamental theories of physisorption, basis of models and their deficiencies are reviewed. It can provide guidance on developing a modified Kelvin's equation for pore size calculation.%介绍了物理吸附法评价介孔材料孔结构参数的理论基础、孔介质模型及吸附质对测量结果准确性的影响因素.讨论了Kelvin公式,以及从不同方面对Kelvin公式进行的修正,并以此为基础,评述采用物理吸附法测定介孔材料各种孔结构测试方法,着重探讨物理吸附法的理论基础、模型建立及其不足之处,分析和探讨介孔材料孔结构表征中存在的问题及原因,为建立新的理论模型探讨思路与可能.

  3. High-resolution noncontact AFM and Kelvin probe force microscopy investigations of self-assembled photovoltaic donor–acceptor dyads

    Science.gov (United States)

    Schwartz, Pierre-Olivier; Biniek, Laure; Brinkmann, Martin; Leclerc, Nicolas; Zaborova, Elena

    2016-01-01

    Summary Self-assembled donor–acceptor dyads are used as model nanostructured heterojunctions for local investigations by noncontact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). With the aim to probe the photo-induced charge carrier generation, thin films deposited on transparent indium tin oxide substrates are investigated in dark conditions and upon illumination. The topographic and contact potential difference (CPD) images taken under dark conditions are analysed in view of the results of complementary transmission electron microscopy (TEM) experiments. After in situ annealing, it is shown that the dyads with longer donor blocks essentially lead to standing acceptor–donor lamellae, where the acceptor and donor groups are π-stacked in an edge-on configuration. The existence of strong CPD and surface photo-voltage (SPV) contrasts shows that structural variations occur within the bulk of the edge-on stacks. SPV images with a very high lateral resolution are achieved, which allows for the resolution of local photo-charging contrasts at the scale of single edge-on lamella. This work paves the way for local investigations of the optoelectronic properties of donor–acceptor supramolecular architectures down to the elementary building block level. PMID:27335768

  4. A new material identification pattern for the fractional Kelvin-Zener model describing biomaterials and human tissues

    Science.gov (United States)

    Spasic, Dragan T.; Kovincic, Nemanja I.; Dankuc, Dragan V.

    2016-08-01

    The aim of this study is to describe several biomaterials and tissues using a simple material identification pattern applied to the fractional Kelvin-Zener model of viscoelastic body and standard mechanical tests. Each of the descriptions comprises the order of fractional derivative of stress and strain, modulus of elasticity, and stress and strain relaxation constants that obey restrictions imposed by the Clausius-Duhem inequality. These four parameters are obtained by use of the Laplace transform, Post's inversion formula and Newton's method. The suggested approach can serve as an alternative to quasilinear viscoelasticity providing a physically uniform quantitative measure for biomaterials/tissues comparison and can be applied to real data. It works for nonsmooth inputs too. Regarding biomaterials the comparison between an etched poly lactic-co-glycolic acid membrane and the corresponding composite scaffold was made. With respect to human tissues the tympanic membrane, the stapedial tendon, and the stapedial annular ligament were described. The obtained mechanical response for examined cases is in agreement with the experimentally recorded one.

  5. Charge transfer of single laser crystallized intrinsic and phosphorus-doped Si-nanocrystals visualized by Kelvin probe force microscopy

    Science.gov (United States)

    Xu, Jie; Xu, Jun; Lu, Peng; Shan, Dan; Li, Wei; Chen, Kunji

    2014-10-01

    Isolated intrinsic and phosphorus doped (P-doped) Si-nanocrystals (Si-NCs) on n- and p-Si substrates are fabricated by excimer laser crystallization techniques. The formation of Si-NCs is confirmed by atomic force microscopy (AFM) and conductive AFM measurements. Kelvin probe force microscopy (KPFM) is then carried out to visualize the trapped charges in a single Si-NC dot which derives from the charge transfer between Si-NCs and Si substrates due to their different Fermi levels. The laser crystallized P-doped Si-NCs have a similar Fermi level around the mid-gap to the intrinsic counterparts, which might be caused by the inactivated impurity atoms or the surface states-related Fermi level pinning. A clear rise of the Fermi level in P-doped Si-NCs is observed after a short time thermal annealing treatment, indicating the activation of dopants in Si-NCs. Moreover, the surface charge quantity can be estimated using a simple parallel plate capacitor model for a quantitative understanding of the KPFM results at the nanoscale.

  6. Charge transfer of single laser crystallized intrinsic and phosphorus-doped Si-nanocrystals visualized by Kelvin probe force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jie; Xu, Jun, E-mail: junxu@nju.edu.cn; Lu, Peng; Shan, Dan; Li, Wei; Chen, Kunji [National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2014-10-07

    Isolated intrinsic and phosphorus doped (P-doped) Si-nanocrystals (Si-NCs) on n- and p-Si substrates are fabricated by excimer laser crystallization techniques. The formation of Si-NCs is confirmed by atomic force microscopy (AFM) and conductive AFM measurements. Kelvin probe force microscopy (KPFM) is then carried out to visualize the trapped charges in a single Si-NC dot which derives from the charge transfer between Si-NCs and Si substrates due to their different Fermi levels. The laser crystallized P-doped Si-NCs have a similar Fermi level around the mid-gap to the intrinsic counterparts, which might be caused by the inactivated impurity atoms or the surface states-related Fermi level pinning. A clear rise of the Fermi level in P-doped Si-NCs is observed after a short time thermal annealing treatment, indicating the activation of dopants in Si-NCs. Moreover, the surface charge quantity can be estimated using a simple parallel plate capacitor model for a quantitative understanding of the KPFM results at the nanoscale.

  7. Performance of a 4 Kelvin pulse-tube cooled cryostat with dc SQUID amplifiers for bolometric detector testing

    CERN Document Server

    Barron, Darcy; Keating, Brian; Quillin, Ron; Stebor, Nathan; Wilson, Brandon

    2013-01-01

    The latest generation of cosmic microwave background (CMB) telescopes is searching for the undetected faint signature of gravitational waves from inflation in the polarized signal of the CMB. To achieve the unprecedented levels of sensitivity required, these experiments use arrays of superconducting Transition Edge Sensor (TES) bolometers that are cooled to sub-Kelvin temperatures for photon-noise limited performance. These TES detectors are read out using low- noise SQUID amplifiers. To rapidly test these detectors and similar devices in a laboratory setting, we constructed a cryogenic refrigeration chain consisting of a commercial two-stage pulse-tube cooler, with a base temperature of 3 K, and a closed-cycle 3He/4He/3He sorption cooler, with a base temperature of 220 mK. A commercial dc SQUID system, with sensors cooled to 4 K, was used as a highly-sensitive cryogenic ammeter. Due to the extreme sensitivity of SQUIDs to changing magnetic fields, there are several challenges involving cooling them with puls...

  8. Kinetic effects on the Kelvin-Helmholtz instability in ion-to-magnetohydrodynamic scale transverse velocity shear layers: Particle simulations.

    Science.gov (United States)

    Nakamura, T K M; Hasegawa, H; Shinohara, I

    2010-04-01

    Ion-to-magnetohydrodynamic scale physics of the transverse velocity shear layer and associated Kelvin-Helmholtz instability (KHI) in a homogeneous, collisionless plasma are investigated by means of full particle simulations. The shear layer is broadened to reach a kinetic equilibrium when its initial thickness is close to the gyrodiameter of ions crossing the layer, namely, of ion-kinetic scale. The broadened thickness is larger in B⋅Ω0 case, where Ω is the vorticity at the layer. This is because the convective electric field, which points out of (into) the layer for B⋅Ω0), extends (reduces) the gyrodiameters. Since the kinetic equilibrium is established before the KHI onset, the KHI growth rate depends on the broadened thickness. In the saturation phase of the KHI, the ion vortex flow is strengthened (weakened) for B⋅Ω0), due to ion centrifugal drift along the rotational plasma flow. In ion inertial scale vortices, this drift effect is crucial in altering the ion vortex size. These results indicate that the KHI at Mercury-like ion-scale magnetospheric boundaries could show clear dawn-dusk asymmetries in both its linear and nonlinear growth.

  9. Convective drying of a macroporous medium: a comparison of original porous asphalt geometry with randomized Kelvin cells

    Science.gov (United States)

    Lal, Sreeyuth; Lucci, Francesco; Defraeye, Thijs; Poulikakos, Lily; Partl, Manfred; Derome, Dominique; Carmeliet, Jan

    2015-11-01

    Forced convective drying of a macroporous medium is a complex interplay of enhanced air-vapor mixing due to turbulent airflow at the air-solid interface and the momentum transfer resulting from air infiltration into the material. Such air infiltration is expected to have a non-trivial effect on the drying rate of a material like porous asphalt (PA), which is characterized by large, interconnected pores open to the surface. Through a series of CFD simulations performed on an original PA geometry extracted from CT scans, we quantify the relative impacts of interior material resistance and boundary layer resistance on moisture transport in PA. At wind speeds below 1 m/s, the effect of material resistance on the total moisture transfer is found to be high due to low air infiltration. At higher wind speeds, air infiltration increases by which the material resistance decreases. Similar simulations are performed on an idealized PA geometry made from randomized Kelvin cells (KC) since they are computationally less expensive, and thus ideal for parametric studies. However, in KC cells, drying from air infiltration is stronger than diffusive drying even at low wind speeds. This shows the need to fine-tune the pore connectivity of KC to better match the air infiltration observed in PA. This research was supported by a Swiss National Science Foundation (SNSF) Grant (200021-143651).

  10. Direct assessment of p-n junctions in single GaN nanowires by Kelvin probe force microscopy

    Science.gov (United States)

    Minj, Albert; Cros, Ana; Auzelle, Thomas; Pernot, Julien; Daudin, Bruno

    2016-09-01

    Making use of Kelvin probe force microscopy, in dark and under ultraviolet illumination, we study the characteristics of p-n junctions formed along the axis of self-organized GaN nanowires (NWs). We map the contact potential difference of the single NW p-n junctions to locate the space charge region and directly measure the depletion width and the junction voltage. Simulations indicate a shrinkage of the built-in potential for NWs with small diameter due to surface band bending, in qualitative agreement with the measurements. The photovoltage of the NW/substrate contact is studied by analyzing the response of NW segments with p- and n-type doping under illumination. Our results show that the shifts of the Fermi levels, and not the changes in surface band bending, are the most important effects under above band-gap illumination. The quantitative electrical information obtained here is important for the use of NW p-n junctions as photovoltaic or rectifying devices at the nanoscale, and is especially relevant since the technique does not require the formation of ohmic contacts to the NW junction.

  11. 2D hybrid simulations of super-diffusion at the magnetopause driven by Kelvin-Helmholtz instability

    Energy Technology Data Exchange (ETDEWEB)

    Cowee, Misa M [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Gary, S Peter [Los Alamos National Laboratory

    2009-01-01

    This manuscript describes the self-consistent simulation of diffusion at the magnetopause driven by Kelvin-Helmholtz (KH) instability. Two-dimensional hybrid (kinetic ions, fluid electrons) simulations of the most KH-unstable configuration where the shear flow is oriented perpendicular to the uniform magnetic field are carried out. The motion of the simulation particles are tracked during the run and their mean-square displacement normal to the magnetopause is calculated from which diffusion coefficients are determined. The diffusion coefficients are found to be time dependent, with D{sub x} {proportional_to} t{sup {alpha}}, where {alpha} > 1. Additionally, the probability distribution functions (PDF) of the 'jump lengths' the particles make over time are found to be non-gaussian. Such time-dependent diffusion coefficients and non-gaussian PDF's have been associated with so-called 'super-diffusion', in which diffusive mixing of particles is enhanced over classical diffusion. The results indicate that while turbulence associated with the break-down of vortices contributes to this enhanced diffusion, it is the growth of large-scale, coherent vortices is the more important process in facilitating it.

  12. Observations of vortex merger and growth reduction in a dual-mode, supersonic Kelvin-Helmholtz instability experiment

    Science.gov (United States)

    Wan, Willow; Malamud, Guy; Shimony, Assaf; Trantham, Matt; Klein, Sallee; Shvarts, Dov; Kuranz, Carolyn; Drake, R. Paul

    2015-11-01

    The Kelvin-Helmholtz instability (KHI) generates vortical structures and turbulence at an interface with shear flow. This instability is ubiquitous in natural and engineering systems including astrophysical environments and laboratory plasmas. Detailed measurements of modulation amplitude growth reduction and vortex merger evolving from well-defined initial conditions can benchmark hydrodynamic models and theories. This experiment provides the first measurements of the vortex merger rate of well-characterized seed perturbations evolving under the influence of the KHI in a supersonic flow. These data were obtained by utilizing a sustained laser pulse to drive a steady shockwave into low-density carbon foam, introducing shear along a precision-machined plastic interface. The evolution and merger of the modulations was measured with x-ray radiography and reproduced with 2D hydrodynamic simulations. This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840, and the National Laser User Facility Program, grant number DE-NA0002032, and through the Laboratory for Laser Energetics, University of Rochester by the NNSA/OICF under Cooperative Agreement No. DE-FC52-08NA28302.

  13. Interference pattern of the sound field in the presence of an internal Kelvin wave in a stratified lake.

    Science.gov (United States)

    Katsnelson, Boris; Lunkov, Andrey; Ostrovsky, Ilia

    2016-02-01

    Internal Kelvin waves (IKWs) initiated by rotation of the Earth are one of the main hydrodynamic phenomena in large stratified lakes where baroclinic Rossby radius of deformation is smaller than the horizontal scale of the lake. IKWs can be identified using the spectra of internal waves, where in the presence of IKWs, the inertial frequency is at maximum. IKWs play a rather important role in the lake's dynamics for different processes, both in the water layer and sediment, especially at the periphery of lake. Due to influence of internal waves on the sound propagation, acoustical methods can be used for estimation of behaviour of IKWs. In this paper, the spatiotemporal variability of the mid-frequency (∼1 kHz) sound field in the presence of IKWs in a deep stratified Lake Kinneret is studied using numerical simulations based on normal-mode theory. Due to the specific character of perturbation of the water layer, IKWs can cause specific variations of interference pattern, in particular, a significant shift of the sound interference pattern both in spatial and frequency domain. These shifts can be easily measured and used for reconstruction of IKW parameters.

  14. Contact resistance asymmetry of amorphous indium-gallium-zinc-oxide thin-film transistors by scanning Kelvin probe microscopy

    Science.gov (United States)

    Chen-Fei, Wu; Yun-Feng, Chen; Hai, Lu; Xiao-Ming, Huang; Fang-Fang, Ren; Dun-Jun, Chen; Rong, Zhang; You-Dou, Zheng

    2016-05-01

    In this work, a method based on scanning Kelvin probe microscopy is proposed to separately extract source/drain (S/D) series resistance in operating amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. The asymmetry behavior of S/D contact resistance is deduced and the underlying physics is discussed. The present results suggest that the asymmetry of S/D contact resistance is caused by the difference in bias conditions of the Schottky-like junction at the contact interface induced by the parasitic reaction between contact metal and a-IGZO. The overall contact resistance should be determined by both the bulk channel resistance of the contact region and the interface properties of the metal-semiconductor junction. Project supported by the Key Industrial R&D Program of Jiangsu Province, China (Grant No. BE2015155), the Priority Academic Program Development of Higher Education Institutions of Jiangsu Province, China, and the Fundamental Research Funds for the Central Universities, China (Grant No. 021014380033).

  15. Interference pattern of the sound field in the presence of an internal Kelvin wave in a stratified lake.

    Science.gov (United States)

    Katsnelson, Boris; Lunkov, Andrey; Ostrovsky, Ilia

    2016-02-01

    Internal Kelvin waves (IKWs) initiated by rotation of the Earth are one of the main hydrodynamic phenomena in large stratified lakes where baroclinic Rossby radius of deformation is smaller than the horizontal scale of the lake. IKWs can be identified using the spectra of internal waves, where in the presence of IKWs, the inertial frequency is at maximum. IKWs play a rather important role in the lake's dynamics for different processes, both in the water layer and sediment, especially at the periphery of lake. Due to influence of internal waves on the sound propagation, acoustical methods can be used for estimation of behaviour of IKWs. In this paper, the spatiotemporal variability of the mid-frequency (∼1 kHz) sound field in the presence of IKWs in a deep stratified Lake Kinneret is studied using numerical simulations based on normal-mode theory. Due to the specific character of perturbation of the water layer, IKWs can cause specific variations of interference pattern, in particular, a significant shift of the sound interference pattern both in spatial and frequency domain. These shifts can be easily measured and used for reconstruction of IKW parameters. PMID:26936569

  16. Contact resistance asymmetry of amorphous indium–gallium–zinc–oxide thin-film transistors by scanning Kelvin probe microscopy

    Science.gov (United States)

    Chen-Fei, Wu; Yun-Feng, Chen; Hai, Lu; Xiao-Ming, Huang; Fang-Fang, Ren; Dun-Jun, Chen; Rong, Zhang; You-Dou, Zheng

    2016-05-01

    In this work, a method based on scanning Kelvin probe microscopy is proposed to separately extract source/drain (S/D) series resistance in operating amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors. The asymmetry behavior of S/D contact resistance is deduced and the underlying physics is discussed. The present results suggest that the asymmetry of S/D contact resistance is caused by the difference in bias conditions of the Schottky-like junction at the contact interface induced by the parasitic reaction between contact metal and a-IGZO. The overall contact resistance should be determined by both the bulk channel resistance of the contact region and the interface properties of the metal-semiconductor junction. Project supported by the Key Industrial R&D Program of Jiangsu Province, China (Grant No. BE2015155), the Priority Academic Program Development of Higher Education Institutions of Jiangsu Province, China, and the Fundamental Research Funds for the Central Universities, China (Grant No. 021014380033).

  17. Forming Planetesimals by Gravitational Instability: I. The Role of the Richardson Number in Triggering the Kelvin-Helmholtz Instability

    CERN Document Server

    Lee, Aaron T; Asay-Davis, Xylar; Barranco, Joseph

    2010-01-01

    Gravitational instability (GI) of a dust-rich layer at the midplane of a gaseous circumstellar disk is one proposed mechanism to form planetesimals, the building blocks of rocky planets and gas giant cores. Self-gravity competes against the Kelvin-Helmholtz instability (KHI): gradients in dust content drive a vertical shear which risks overturning the dusty subdisk and forestalling GI. To understand the conditions under which the disk can resist the KHI, we perform 3D simulations of stratified subdisks in the limit that dust particles are small and aerodynamically well coupled to gas. This limit screens out the streaming instability and isolates the KHI. Each subdisk is assumed to have a vertical density profile given by a spatially constant Richardson number Ri. We vary Ri and the midplane dust-to-gas ratio mu and find that the critical Richardson number dividing KH-unstable from KH-stable flows is not unique; rather Ri_crit grows nearly linearly with mu for mu=0.3-10. Only for disks of bulk solar metallicit...

  18. 2016 SPD: Day 3

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    last the longest 2 minutes and 40 seconds is the small town of Hopkinsville, KY. WKU is located a little over an hour away, and both locations are prepared for a large influx of people on eclipse day!Partial solar eclipse as viewed by the space-based Solar Dynamics Observatory. [NASA/SDO]WKU is located just off the centerline of eclipse path, which has some advantages: this provides better viewing of some of the chromospheric features of the Sun during the eclipse, like priminences and solar loops. WKU is setting up a variety of educational and public outreach activities at their football stadium and the WKU farm, and they encourage you to come visit for the eclipse!In addition, they are participating in a nationwide experiment called Citizen CATE, short for the Continental American Telescopic Eclipse. This project will use 60 telescopes spanning the 2500 mile path of totality to record continuous data of the eclipse as it travels across the US. The result will be data of a remarkable 90 minutes of totality, revealing the activity of the solar corona and providing an extended view of the eclipse as has never been seen before.Science During the EclipseNext up was Shadia Habbal (University of Hawaii), who is a co-leader of the AAS 2017 Eclipse Task Force. In addition to her education and outreach efforts associated with the eclipse, however, Habbal is a solar eclipse researcher. She and her collaborators are known as the Solar Wind Sherpas, due to the fact that they hand-carry their science equipment around the world for solar eclipses!Solar corona during a 2008 eclipse, with color overlay indicating emission from highly ionized iron lines. [Habbal et al. 2010]The primary science done during solar eclipses is the study of the solar corona, the region that extends from the solar surface out to several solar radii. This region is too faint to observe normally, but when the light from the Suns disk is blocked out, we can examine it.Unfortunately, the space telescopes that

  19. AAS 228: Day 4

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    Editors Note: Lastweek we were at the 228th AAS Meeting in San Diego, CA. Here is a final post aboutselectedevents on the last day of the meeting, written by authors fromastrobites.com, a grad-student collaborative project with which we recently announced a new partnership! Starting in July,keep an eye out for astrobites postsat AAS Nova in between Highlights(i.e., on Tuesdays and Thursdays).Were excited to be working together to bring you more recent astronomy research from AAS journals!Extrasolar Planets: Detection (by Leonardo dos Santos)Thursdays first session on exoplanets was about detecting these distant worlds, and the opening talk was given by Robert Siverd (Las Cumbres Observatory). He describes the NRES, a network of spectrographs that will look for exoplanets using the radial velocity method. One of the coolest aspects of this instrument is that it will feature an on the fly scheduling system that will perform observations as efficiently as possible. The spectrograph is still being tested, but a unit will be deployed at CTIO later this year.@lcogt contracted by @NASA_TESS for follow up of their candidates. #aas228 Jessie Christiansen (@aussiastronomer) June 16, 2016Measuring the depths of transits and eclipses in Spitzer has been problematic in the past, since the Spitzer instrument IRAC (InfraRed Array Camera) has a non-uniform response in its detectors pixels. But, as reported by James Ingalls (Spitzer Science Center, Caltech), observers are circumventing this issue by using what they call the staring mode (avoiding large pointing jumps) and an algorithm to pick sweet spot pixels. Moreover, the results from the IRAC Data Challenge are helping to better understand its behavior. Giuseppe Morello (University College London), on the other hand, explained how his research group gets rid of instrumental effects from IRAC using machine learning. This method removes systematics from exoplanet transit data no matter if the noise source is from an instrument or

  20. Earth Day 2010: Earth Day 40th Anniversary Poster

    OpenAIRE

    Nowacka, Izabela

    2010-01-01

    EGJ Issue 30 Earth Day 2010 ISSN 1076-7975 In celebration of 40th Earth Day the Electronic Green Journal presents one contemporary and twelve posters from 1970s focusing on ecology and the environment.

  1. The comparison of compensatory sweating after T2-4 and T3-4 endoscopic thoracic sympathectomy for the treatment of palmar hyperhidrosis.%T2-4与T3-4交感神经链切断治疗手足多汗症术后代偿性出汗比较

    Institute of Scientific and Technical Information of China (English)

    陈惠国; 黄邵洪; 谷力加; 廖洪映; 张健; 李昀; 蔡松旺

    2011-01-01

    Objective: To compare compensatory sweating after T2-4 and T3-4 endoscopic thoracic sympathecto-my for the treatment of palmar hyperhidrosis, and thus to investigate the potential mechanism of the occurrence of compensatory sweating. Methods; One hundred and forty-six patients with primary palmar hyperhidrosis were divided into two groups; 66 with T2-4 sympathectomy (T2-4 group) and 80 with T3-4 sympathectomy (T3-4 group). The effects of operation, compensatory sweating location and severity one day and 6 months after operation were compared. Results; The effective rate was 100% , and the most common compensatory sweating locations were on the back and the chest The compensatory sweating incidence was 39% and 21% respectively in T2-4 and T3-4 group with significant difference ( P < 0. 05 ). There were 2 cases of severe compensatory sweating in T2-4 group, and T3-4 group without severe case 1 day after operation. The compensatory sweating incidence was 24% and 11 % respectively , with significant difference ( P < 0. 05). There was 1 case of severe compensatory sweating in T2-4 group, and T3-4 group without severe case 6 months after operation. Conclusion; Lowering the level of sympathectomy for primary palmar hyperhidrosis results in less compensatory sweeting. T3-4 sympathectomy is an ideal operation method to reduce compensatory sweating.%目的:通过比较胸腔镜下T2-4与T3-4交感神经链切断治疗手足多汗症术后代偿性出汗发生情况,探讨其发生的可能机制.方法:手足多汗症患者146例,按不同手术方式分为T2-4组(行T2-4水平交感神经链切断术,共66例)与T3-4组(行T3-4水平交感神经链切断术,共80例).比较两组术后第1日、第6个月手术效果以及代偿性出汗发生部位和严重程度.结果:术后两组手汗治愈率100%,最常见代偿性出汗部位是背部和胸部.术后第1日T2-4组代偿性出汗发生率明显高于T3-4组(39%对比21%,P<0.05),T2-4组出现2

  2. AAS 227: Day 1

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or at astrobites.com, or catch ourlive-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto have so many people tell us that they already know about and useastrobites, and we were excited to introduce a new cohort of students at AAS to astrobites for the first time.Tuesday morning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended today.Opening Address (by Becky Smethurst)The President of the AAS, aka our fearless leader Meg Urry kicked off the meeting this morning at the purely coffee powered hour of 8am this morning. She spoke about the importance of young astronomers at the meeting (heres looking at you reader!) and also the importance of the new Working Group for Accessibility and Disabilities (aka WGAD pronounced like wicked) at the AAS. The Society has made extra effort this year to make the conference accessible to all,a message which was very well received by everyone in attendance.Kavli Lecture: New Horizons Alan Stern (by Becky Smethurst)We were definitely spoilt with the first Plenary lecture at this years conference Alan Stern gave us a a review of the New Horizons mission of the Pluto Fly By (astrobites covered the mission back in July with this post). We were treated to beautiful images, wonderful results and a foray into geology.Before (Hubble) and after #NewHorizons. #thatisall #science #astro alanstern #aas227 pic.twitter.com/kkMt6RsSIR Science News (@topsciencething) January 5, 2016Some awesome facts from the lecture that blew my mind:New Horizons is now 2AU (!) beyond Pluto

  3. PtdIns(3,4,5)P3 is a regulator of myosin-X localization and filopodia formation

    DEFF Research Database (Denmark)

    Plantard, Laure; Arjonen, Antti; Lock, John G;

    2010-01-01

    Phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] is a key regulator of cell signaling that acts by recruiting proteins to the cell membrane, such as at the leading edge during cell migration. Here, we show that PtdIns (3,4,5)P3 plays a central role in filopodia formation via the bindi...

  4. Implementation of "Marginalism" in day to day life

    OpenAIRE

    Shkedy, Elyezer

    1998-01-01

    Approved for public release; distribution is unlimited Economics, and especially the theory of Marginalism, can be very useful in "day-to-day" life, but for many reasons people do not really use it. This work tries to explain the "economic way of thinking" basically by verbally explaining the main idea, by providing examples from day-to-day life with minimum needed mathematics, and exploring the most important steps in the decision-making process. Hopefully, this work will encourage people...

  5. ELECTROSYNTHESIS AND CHARACTERIZATION OF POLY(HYDROXYMETHYLATED-3,4-ETHYLENEDIOXYTHIOPHENE) FILM IN AQUEOUS MICELLAR SOLUTION AND ITS BIOSENSING APPLICATION

    Institute of Scientific and Technical Information of China (English)

    Yao Lu; Yang-ping Wen; Bao-yang Lu; Xue-min Duan; Jing-kun Xu; Long Zhang; Yao Huang

    2012-01-01

    A new and efficient synthetic route to hydroxymethylated-3,4-ethylenedioxylthiophene (EDOT-MeOH) was developed by a simple four-step sequence,and its global yield was approximately 41.06%.The poly(hydroxymethylated-3,4-ethylenedioxylthiophene) (PEDOT-MeOH) film was electrosynthesized in aqueous sodium dodecylsulfate micellar solutions and characterized by different methods.The EDOT-MeOH possessed better water solubility,and lower onset oxidation potential than EDOT.The as-obtained PEDOT-MeOH film displayed good reversible redox activity,stability and capacitance properties in a monomer-free electrolyte,especially the good solubility of PEDOT-MeOH film in strong polar organic solvents such as dimethyl sulfoxide and tetrahydrofuran created a potential application in many different fields.Fluorescent spectra indicated that PEDOT-MeOH was a yellow-green-light-emitter with maximum emission at 568 nm.The as-formed PEDOT-MeOH film had good biocompatibility and was used for fabricating the electrochemical vitamin C biosensor.The proposed biosensor showed a linear range of 3 × 10 6 mol/L to 1.2 × 10-2 mol/L with the detection limit of 1 μmol/L,a sensitivity of 95.6 μA (mmol/L)-1 cm-2,and a current response time less than 10 s and a fairly good stability (The relative standard deviation was 0.43% for 20 successive assays,the proposed biosensor still retained 93.5% of bioactivity after 15 days storage.This result indicated that the prepared PEDOT-MeOH film as immobilization matrix of biologically-active species could be a promising candidate for the design and application of biosensor.

  6. Mandibular repositioning modulates IGFBP-3, -4, -5 and -6 expression in the mandibular condylar cartilage of young rats.

    Science.gov (United States)

    Hajjar, Denise; Santos, Marinilce F; Kimura, Edna Teruko

    2006-01-01

    Functional orthopedic appliances correct dental malocclusion partially by exerting indirect mechanical stimulus on the condylar cartilage, modulating growth and the adaptation of orofacial structures. However, the exact nature of the biological responses to this therapy is not well understood. Insulin-like growth factors I and II (IGF-I and II) are important local factors during growth and differentiation in the condylar cartilage [D. Hajjar, M.F. Santos and E.T. Kimura, Propulsive appliance stimulates the synthesis of insulin-like growth factors I and II in the mandibular condylar cartilage of young rats, Arch. Oral Biol. 48 (2003), 635-642]. The bioefficacy of IGFs at the cellular level is modulated by IGF binding proteins (IGFBP). The aim of this study was to verify the mRNA and protein expression of IGFBP-3, IGFBP-4, IGFBP-5 and IGFBP-6 in the condylar cartilage of young male Wistar rats that used a mandibular propulsive appliance for 3, 9, 15, 20, 30 or 35 days. For this purpose, sagittal sections of decalcified and paraffin-embedded condyles were submitted to immunohistochemistry and the condylar cartilage to RT-PCR. The control group showed a gradual increase in the protein expression of all IGFBPs, except IGFBP-4. Following use of the appliance, IGFBP-3 and IGFBP-6 expression decreased in the early stage of the treatment. At 20 days of treatment there was a decline in the IGFs and IGFBP-3, IGFBP-4 and IGFBP-5 expression and at 30 days there was a peak in the IGFs and all IGFBPs expression except for IGFBP-3 where the peak was observed in the control animals. The expression patterns of all IGFBPs in the condylar cartilage were similar. The modulation of IGFBP-3, -4, -5 and -6 expression in the condylar cartilage in response to the propulsive appliance suggests that those peptides are involved in the mandibular adaptation during this therapy.

  7. Synthesis of New [1,2,4]Triazolo[3,4-b][1,3,4]thiadiazines and Study of Their Anti-Candidal and Cytotoxic Activities

    Directory of Open Access Journals (Sweden)

    Mashooq Ahmad Bhat

    2014-01-01

    Full Text Available New triazolothiadiazine derivatives 5a–h were synthesized from 4-amino-3-(4-pyridyl-5-mercapto-4H-1,2,4-triazole (3 with substituted aryl hydrazonoyl chlorides 4a–h. The compounds were tested in vitro against eleven Candida species and compared with standard drug ketoconazole. Among these compounds, the compounds bearing p-chlorophenyl 5e, p-methoxyphenyl 5c, phenyl 5a, and p-sulphonamidophenyl 5g substituents on triazolothiadiazine system were found to be the most effective derivatives against Candida species. Compound 5e was the most effective compound against C. parapsilosis (ATCC 22019, C. albicans (ATCC 66027, C. specie [blood] 12810, and C. specie [urine] 300 with MIC value of 6.25 μg/mL, whereas ketoconazole exhibits the inhibitory activity with MIC value of 3–30 μg/mL against all tested strains. It was clear that there is a positive correlation between anti-Candidal activity and p-chlorophenyl substitution on triazolothiadiazine ring. All the synthesized compounds were also investigated for their potential cytotoxicity on noncancer cell line (MCF-12 using WST-1 assay. Three compounds 5d, 5a, and 5h were found to have the same IC50 value as that of standard drug ketoconazole against noncancer cell line MCF-12 (IC50 ≥ 1.0 × 105 μg/mL.

  8. Development of full power risk monitoring system for nuclear power plant for UCN 3, 4

    International Nuclear Information System (INIS)

    Recently, RIA/R has been widely used which reduce costs by optimizing resources. One of essential RIAs is the development of computerized risk monitoring system which can evaluated the risk in real time using the plant configuration information such as basic event of inoperable equipments and environmental variables. KAERI has developed the full power risk monitoring system (DynaRM) for the UCN 3,4 NPPs. In order to develop UCN 3,4 full power risk monitoring system PSA model for risk monitor should be developed with reflecting the changes of plant configuration from the beginning of plant operation. As a risk monitor system, two main modules have been developed to monitor the current risk of the plant and to assist the maintenance schedule decision making

  9. 1-取代-1,2,3,4-四氢-9H-吡啶并[3,4-b]吲哚-3-羧酸甲酯的合成及表征%Synthesis and Characterization of 1-Substituted - 1,2,3,4-Tetrahydro -9H-Pyrido[3,4-b]Indole-3-Carboxylic Acid Methyl Ester

    Institute of Scientific and Technical Information of China (English)

    马养民; 李延超; 郭会

    2012-01-01

    以L-色氨酸甲酯盐酸盐为起始原料,经过Pictet-Spengler反应,再通过结晶诱导不对称转化(CIAT)过程,最后用饱和碳酸钠溶液脱除盐酸后高效选择性的得到1-取代-1,2,3,4-四氢-9H-吡啶并[3,4-b]吲哚-3-羧酸甲酯,目标产物通过重结晶或者柱层析方法纯化,所有化合物的结构均经元素分析,IR,1H NMR,13C NMR确证.

  10. Synthesis, Crystal Structure, and Herbicidal Activities of 2-Cyanoacrylates Containing 1,3,4-Thiadiazole Moieties

    Institute of Scientific and Technical Information of China (English)

    Wang Tingting; Miao Wenke; Wu Shanshan; Bing Guifang; Zhang Xin; Qin Zhenfang; Yu Haibo; Qin Xue; Fang Jianxin

    2011-01-01

    Three series of novel 2-cyanoacrylates 7a-7f, 9a-9f, 10a-10f containing 1,3,4-thiadiazole ring moieties were synthesized as herbicidal inhibitors of photosystem Ⅱ (PS Ⅱ) electron transportation. Their structures were clearly verified by 1H NMR, 13C NMR, elemental analysis (or HRMS analysis) and single-crystal X-ray diffraction analysis. Bioassay showed that a suitable group at the 3-position of acrylates was essential for high herbicidal activ-ity. In particular, compound 7e showed the best herbicidal activities and gave 100% inhibitory activity against rape and amaranth pigweed at a dose of 1.5 kg/ha. Introduction of substituent with higher polarity such as sulfinyl or sulfonyl to the 5-position of 1,3,4-thiadiazole decreased herbicidal activities.

  11. Synthesis and Antibacterial Activities of Novel Imidazo[2,1-b]-1,3,4-thiadiazoles

    Directory of Open Access Journals (Sweden)

    Kamal F. M. Atta

    2011-06-01

    Full Text Available 2-Amino-5-(2-aryl-2H-1,2,3-triazol-4-yl-1,3,4-thiadiazoles 2-4 have been synthesized by the reaction of 2-aryl-2H-1,2,3-triazole-4-carboxylic acids 1 with thiosemicarbazide. Their reaction with phenacyl (p-substituted phenacyl bromides led to formation of the respective 6-aryl-2-(2-aryl-2H-1,2,3-triazol-4-ylimidazo[2,1-b]-1,3,4-thiadiazoles 5. Reactivity of the latter fused ring towards reaction with different electrophilic reagents afforded the corresponding 5-substituted derivatives 6-8. The structure of the above compounds was confirmed from their spectral characteristics. Some of these compounds were found to possess slight to moderate activity against the microorganisms Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and Escherichia coli.

  12. A Convenient Synthesis of Benzo-1,2,3,4-tetrazine-1,3-dioxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-wei; ZHAO Xiu-xiu; LIN Zhi-hui; PANG Si-ping; SUN Cheng-hui; LI Sheng-hua

    2013-01-01

    Benzo-1,2,3,4-tetrazine-1,3-dioxide was synthesized from 2-bromonitrobenzene,which is converted to 2-bromo-1-( tert-butyl-NNO-azoxy)benzene by a three-step standem reaction. Amination of 2-bromo-1-( tert-butyl-NNO-azoxy)benzene with aqueous ammonia using Cu2 O as the catalyst yielded 2-amino-1-(tert-butyl-NNO-azoxy)benzene,that was cyclized with nitration agents N2O5 or NO2BF4 to give benzo-1,2,3,4-tetrazine-1,3-dioxide. A mild and convenient route was developed. Moreover,the target compound was identified by 1 H NMR,13 C NMR,IR, MS-EI and elemental analysis.

  13. Synthesis and crystal structure of sodium praseodymium polyphosphate, NaPr(PO3)4

    Institute of Scientific and Technical Information of China (English)

    K.Horchani-Naifer; J.Amami; M.Ferid

    2009-01-01

    Reaction of Na2CO3, Pr6O11 and H3PO4 gave the sodium praseodymium polyphosphate NaPr(PO3)4. The title compound crystallized in the monoclinic P21/n space group with a=0.9965(4) nm, b=1.31437(4) nm, c=0.72271(3) nm,β=90.429(3)°, V=0.9465(4) nm3, Z=4, R=0.0493 and wR=0.1266 for 1855 independent reflections. The structure of NaPr(PO3)4 consisted of PrO8 polyhedra sharing oxygen atoms with phosphoric group PO4 to form a three-dimensional framework, delimiting intersecting tunnels in which the sodium ion was located. Each Na+ ion was bonded to seven oxygen atoms.

  14. Crystal structure of 2-(1,3-dioxoindan-2-ylisoquinoline-1,3,4-trione

    Directory of Open Access Journals (Sweden)

    Raza Murad Ghalib

    2015-01-01

    Full Text Available In the title isoquinoline-1,3,4-trione derivative, C18H9NO5, the five-membered ring of the indane fragment adopts an envelope conformation with the nitrogen-substituted C atom being the flap. The planes of the indane benzene ring and the isoquinoline-1,3,4-trione ring make a dihedral angle of 82.06 (6°. In the crystal, molecules are linked into chains extending along the bc plane via C—H...O hydrogen-bonding interactions, enclosing R22(8 and R22(10 loops. The chains are further connected by π–π stacking interations, with centroid-to-centroid distances of 3.9050 (7 Å, forming layers parallel to the b axis.

  15. Coordination Compounds Based on 1,2,3,4-Tetrahydro-isoquinoline-3-carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Markéta Svobodová

    2007-05-01

    Full Text Available Syntheses of 2,6-bis[((3S-3-(methoxycarbonyl-1,2,3,4-tetrahydroisoquinolin-2-ylcarbonyl]pyridine and its coordination compounds with Cu2+, Co2+, Co3+, or Fe3+ are described. By means of 1H- and 13C-NMR spectra it was proved that 2,6-bis[((3S-3-(methoxycarbonyl-1,2,3,4-tetrahydroisoquinolin-2-ylcarbonyl]pyridine as well as its coordination compound with Co3+ exist in the form of a mixture of three conformers, differing in the conformations at the two amide groups present. The prepared coordination compounds were tested in the enantioselective catalysis of the nitroaldol addition of nitromethane with 2-nitrobenzaldehyde or 4-nitrobenzaldehyde, and in the Michael addition of ethyl 2-oxocyclohexanecarboxylate to but-3-en-2-one.

  16. SYNTHESIS OF SOLUBLE POLY(3,4-DIHYDROXY-o-TOLYLENE): REDOX POLYMER

    Institute of Scientific and Technical Information of China (English)

    Sa(a)d Moulay; Fatima M'zyène

    2006-01-01

    Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2-dimethoxybenzene. Chloroform-soluble poly(3,4-dimethoxy-o-tolylene) was obtained with an intrinsic viscosity of 0.034 dL g-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction.Cleavage of the methoxy groups present in this polymer resulted in poly(3,4-dihydroxy-o-tolylene) which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions.

  17. The causality between the rapid rotation of a sunspot and an X3.4 flare

    Institute of Scientific and Technical Information of China (English)

    Xiao-Li Yan; Zhong-Quan Qu; Cheng-Lin Xu; Zhi-Ke Xue; De-Fang Kong

    2009-01-01

    Using multi-wavelength data of Hinode, the rapid rotation of a sunspot in ac-tive region NOAA 10930 is studied in detail. We found extraordinary counterclockwise rotation of the sunspot with positive polarity before an X3.4 flare. From a series of vector magnetograms, it is found that magnetic force lines are highly sheared along the neu-tral line accompanying the sunspot rotation. Furthermore, it is also found that sheared loops and an inverse S-shaped magnetic loop in the corona formed gradually after the sunspot rotation. The X3.4 flare can be reasonably regarded as a result of this movement. A detailed analysis provides evidence that sunspot rotation leads to magnetic field linestwisting in the photosphere. The twist is then transported into the corona and triggers flares.

  18. Application of stochastic variational method to 3-4 body systems with realistic nuclear force

    Energy Technology Data Exchange (ETDEWEB)

    Ohbayashi, Yoshihide [Niigata Univ. (Japan); Varga, K.; Suzuki, Yoshiyuki

    1997-05-01

    SVM (stochastic variational method) was applied to simulate triton and alpha with realistic nuclear force such as Reid V8 (RV8), Argonne V6, V8 (AV6 and aV8). 3-4 body systems were solved by about 300-400 dimensions and the results were agreed with the most accurate solution. Convergence of energy of 3-4 body systems was rapid by using AV6 and AV8 potential, but it was slow by RV8 with strong repulsive force core. The energy values using SVM and GFMC were almost same. Number of dimension to convert the energy of triton was decreased by refinement. (S.Y.)

  19. Crystal structure of tetraethylammonium chloride 3,4,5,6-tetrafluoro-1,2-diiodobenzene

    OpenAIRE

    Jasmine Viger-Gravel; Ilia Korobkov; Bryce, David L.

    2015-01-01

    Equimolar quantities of tetraethylammonium chloride (Et4NCl) and 3,4,5,6-tetrafluoro-1,2-diiodobenzene (o-DITFB or o-C6F4I2) have been co-crystallized in a solution of dichloromethane yielding a pure halogen-bonded compound, 3,4,5,6-tetrafluoro-1,2-diiodobenzene–tetraethyl ammonium chloride (2/1), Et4N+·Cl−·2C6F4I2, in the form of translucent needles. [(Et4NCl)(o-C6F4I2)2] packs in the C2/c space group. The asymmetric unit includes one molecule of DITFB, one Et4N+ cation located on a twofold ...

  20. Synthesis and Antibacterial Activity of N-(unsubstituted-N-(3,4-Methylenedioxyphenylmethylarylsulfonamides

    Directory of Open Access Journals (Sweden)

    *Aziz-ur-Rehman

    2013-12-01

    Full Text Available Sulfonamides belong to an active group with biological activities and these activities can be enhanced by introducing heterocyclic moiety. N-((3,4-methylenedioxyphenylmethyl arylsulfonamides (3a-f were synthesized by gearing up (3,4-methylenedioxyphenylmethyl amine (1 and arylsulfonyl chlorides (2a-f in a weak basic aqueous medium. The target molecules, 6a-f and 7a-f were yielded by the reaction of 3a-f with ethyl iodide (4 and 4-flourobenzyl chloride (5 respectively in a weak basic aprotic polar medium. Structural analysis of the synthesized molecules was processed through the spectral data of IR, 1H-NMR, 13C-NMR and EIMS. All the synthesized molecules were evaluated for the antibacterial activity and remained moderately better inhibitors.