WorldWideScience

Sample records for polar semiannual oscillation

  1. Solar polar magnetic field dependency of geomagnetic activity semiannual variation indicated in the Aa index

    Science.gov (United States)

    Oh, Suyeon; Yi, Yu

    2018-01-01

    Three major hypotheses have been proposed to explain the well-known semiannual variation of geomagnetic activity, maxima at equinoxes and minima at solstices. This study examined whether the seasonal variation of equinoctial geomagnetic activity is different in periods of opposite solar magnetic polarity in order to understand the contribution of the interplanetary magnetic field (IMF) in the Sun-Earth connection. Solar magnetic polarity is parallel to the Earth's polarity in solar minimum years of odd/even cycles but antiparallel in solar minimum years of even/odd cycles. The daily mean of the aa, Aa indices during each solar minimum was compared for periods when the solar magnetic polarity remained in opposite dipole conditions. The Aa index values were used for each of the three years surrounding the solar minimum years of the 14 solar cycles recorded since 1856. The Aa index reflects seasonal variation in geomagnetic activity, which is greater at the equinoxes than at the solstices. The Aa index reveals solar magnetic polarity dependency in which the geomagnetic activity is stronger in the antiparallel solar magnetic polarity condition than in the parallel one. The periodicity in semiannual variation of the Aa index is stronger in the antiparallel solar polar magnetic field period than in the parallel period. Additionally, we suggest the favorable IMF condition of the semiannual variation in geomagnetic activity. The orientation of IMF toward the Sun in spring and away from the Sun in fall mainly contributes to the semiannual variation of geomagnetic activity in both antiparallel and parallel solar minimum years.

  2. Synodic and semiannual oscillations of argon-40 in the lunar exosphere

    Science.gov (United States)

    Hodges, R. Richard; Mahaffy, Paul R.

    2016-01-01

    The neutral mass spectrometer on the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft collected a trove of exospheric data, including a set of high-quality measurements of radiogenic 40Ar over a period of 142 days. Data synthesis studies, using well-established exosphere simulation tools, show that the LADEE argon data are consistent with an exosphere-regolith interaction that is dominated by adsorption and that the desorption process generates the Armand distribution of exit velocities. The synthesis work has uncovered an apparent semiannual oscillation of argon that is consistent with temporal sequestration in the seasonal cold traps created at the poles by the obliquity of the Moon. In addition, the LADEE data provide new insight into the pristine nature of lunar regolith, its spatially varying sorption properties, and the influence of sorption processes on the synodic oscillation of the argon exosphere.

  3. Origins of the Thermosphere-Ionosphere Semiannual Oscillation: Reformulating the "Thermospheric Spoon" Mechanism

    Science.gov (United States)

    Jones, M.; Emmert, J. T.; Drob, D. P.; Picone, J. M.; Meier, R. R.

    2018-01-01

    We demonstrate how Earth's obliquity generates the global thermosphere-ionosphere (T-I) semiannual oscillation (SAO) in mass density and electron density primarily through seasonally varying large-scale advection of neutral thermospheric constituents, sometimes referred to as the "thermospheric spoon" mechanism (TSM). The National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) is used to isolate the TSM forcing of this prominent intraannual variation (IAV) and to elucidate the contributions of other processes to the T-I SAO. An ˜30% SAO in globally averaged mass density (relative to its global annual average) at 400 km is reproduced in the TIME-GCM in the absence of seasonally varying eddy diffusion, tropospheric tidal forcing, and gravity wave breaking. Artificially, decreasing the tilt of Earth's rotation axis with respect to the ecliptic plane to 11.75° reduces seasonal variations in insolation and weakens interhemispheric pressure differences at the solstices, thereby damping the global-scale, interhemispheric transport of atomic oxygen (O) and molecular nitrogen in the thermosphere and reducing the simulated global mass density SAO amplitude to ˜10%. Simulated T-I IAVs in mass density and electron density have equinoctial maxima at all latitudes near the F2 region peak; this phasing and its latitude dependence agree well with empirically inferred climatologies. When tropospheric tides and gravity waves are included, simulated IAV amplitudes and their latitudinal dependence also agree well with empirically inferred climatologies. Simulated meridional and vertical transport of O due to the TSM couples to the upper mesospheric circulation, which also contributes to the T-I SAO through O chemistry.

  4. Self-Sustaining Dynamical Nuclear Polarization Oscillations in Quantum Dots

    DEFF Research Database (Denmark)

    Rudner, Mark Spencer; Levitov, Leonid

    2013-01-01

    Early experiments on spin-blockaded double quantum dots revealed robust, large-amplitude current oscillations in the presence of a static (dc) source-drain bias. Despite experimental evidence implicating dynamical nuclear polarization, the mechanism has remained a mystery. Here we introduce......) and nuclear spin diffusion, which governs dynamics of the spatial profile of nuclear polarization. The proposed framework naturally explains the differences in phenomenology between vertical and lateral quantum dot structures as well as the extremely long oscillation periods....

  5. The role of the Southern Hemisphere semiannual oscillation in the development of a precursor to central and eastern Pacific Southern Oscillation warm events

    Science.gov (United States)

    Meehl, Gerald A.; van Loon, Harry; Arblaster, Julie M.

    2017-07-01

    The semiannual oscillation (SAO) is a twice-yearly northward movement (in May-June-July (MJJ) and November-December-January (NDJ)) of the circumpolar trough of sea level pressure (SLP) in the Southern Hemisphere with effects throughout the troposphere. During MJJ the second harmonic of SLP, describing the SAO, has low values of SLP north of 50°S in the subtropical South Pacific, while the first harmonic, which is dominant over the Australian sector, increases to its peak. This once-a-year peak in negative SLP gradients (decreasing to the east) between Australia and the ocean to its east extends to the equatorial Pacific. Southern Oscillation warm events since 1950, with an intensification of this seasonal cycle, have larger-amplitude SST anomalies in the eastern equatorial Pacific in MJJ and during the following mature phase in NDJ. Weak amplification of the seasonal cycle in MJJ tends to be followed by larger-amplitude SST anomalies in the central equatorial Pacific during NDJ.

  6. Semiannual Variation in the Number of Energetic Electron Precipitation Events Recorded in the Polar Atmosphere

    Science.gov (United States)

    Stozhkov, Y. Ivanovich; Makhmutov, V. S.; Bazilevskaya, G. A.; Krainev, M. B.; Svirkhevskaya, A. K.; Svirzhevsky, N. S.; Mailin, S. Y.

    2003-07-01

    The analysis of the monthly numbers of Electron Precipitation Events (EPEs) recorded at Olenya station (Murmansk region) during 1970-1987, shows the semiannual variation with two maxima centered on April and September. We analyse the interplanetary plasma and geomagnetic indices data sets associated with the EPEs recorded. The possible relationship of this variation and RusselMcPherron, Equino ctial and Axial effects is discussed.

  7. Rapid True Polar Wander Oscillations Preserved In Continuous Orosirian Strata

    Science.gov (United States)

    Mitchell, R. N.; Hoffman, P. F.; Brenner, A.; Xu, X.; Evans, D. A.; Bowring, S. A.; Bleeker, W.

    2014-12-01

    Previous paleomagnetic study of the Orosirian (2050-1800 Ma) Great Slave Supergroup, well exposed on islands in Great Slave Lake on the southeastern margin of the Slave craton, revealed evidence of a regularly reversing, or oscillatory, apparent polar wander path. The paleogeographic utility of paleopoles from the Great Slave Supergroup has been brought into question owing to the possibility of vertical-axis rotations associated with the McDonald transcurrent fault array, but structural corrections can be applied. In a high-resolution paleomagnetic re-sampling of portions of the Great Slave Supergroup, concentrating on the Pethei and Christie Bay Groups in particular, we demonstrate systematic and correlative shifts in declination within structurally uniform homoclinal sections. Positive fold tests further substantiate the primary nature of the paleomagnetic oscillations. Smooth, albeit rapid, declination changes preserved within and between our Great Slave Supergroup sections cannot be trivially explained by structural rotation. True polar wander oscillations (expressed as declination variation locally) may be used to correlate Orosirian strata regionally and globally. Geochronological refinement of the Great Slave Supergroup, both directly and indirectly, should help facilitate any such correlations and those with intrusive rocks both locally and globally. Unconformably overlain by the Et-Then Group that is contemporaneous with the McDonald Fault system, the Great Slave basin and intrusive Compton laccoliths pre-date transcurrent faulting. Increased precision achieved using modern U-Pb (zircon) geochronologic methods on the ca. 1865 Ma Compton laccoliths calibrates the minimum age constraint for Great Slave deposition. Additionally, magnetic susceptibility of a ~350 m-thick section of the Pethei Group reveals a hierarchy of cycles. If interpreted as astronomical cycles, possibly expressed through the effects of insolation on biogenic carbonate precipitation

  8. Trends, quasi-biennial, annual, and semi-annual oscillations in stratospheric SCIAMACHY O3, NO2, and BrO limb data using a multivariate least squares approach

    Energy Technology Data Exchange (ETDEWEB)

    Dikty, Sebastian; Weber, Mark; Savigny, Christian von; Rozanov, Alexei; Burrows, John P. [Institut fuer Umweltphysik, Universitaet Bremen (Germany); Mieruch, Sebastian [Institut fuer Umweltphysik, Universitaet Bremen (Germany); Deutscher Wetterdienst, Offenbach (Germany)

    2011-07-01

    We use the latest version of SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) O{sub 3}, NO{sub 2}, and BrO limb profile data (2003-2008) to quantify the amplitudes of the quasi-biennial (QBO), annual (AO), and semi-annual (SAO) oscillation with the help of a simple multivariate regression model. Results are shown for O{sub 3} from 20-50 km altitude, 12-45 km for NO{sub 2}, and 11-33 km for BrO. The analysis is being carried out with SCIAMACHY data covering all latitudes with the exception of the polar region, where continuous measurements are not available. The overall global yield is approximately 10,000 profiles per month, which are binned into 5 -steps with one zonal mean profile being calculated per month and latitude bin. Our results are compared to results from a similar analysis done with SABER ozone data for the same observational period. We use nighttime SABER ozone in order to avoid artificial signals due to the non-sun synchronous orbit of the TIMED satellite. In addition, total ozone (TOZ) trends in SCIAMACHY data time series are being investigated with respect to the question whether or not trends in the lower stratosphere (from the profiles) are similar to trends in TOZ.

  9. Spherical ion oscillations in a positive polarity gridded inertial-electrostatic confinement device

    Science.gov (United States)

    Bandara, R.; Khachan, J.

    2013-07-01

    A pulsed, positive polarity gridded inertial electrostatic confinement device has been investigated experimentally, using a differential emissive probe and potential traces as primary diagnostics. Large amplitude oscillations in the plasma current and plasma potential were observed within a microsecond of the discharge onset, which are indicative of coherent ion oscillations about a temporarily confined excess of recirculating electron space charge. The magnitude of the depth of the potential well in the established virtual cathode was determined using a differential emissive Langmuir probe, which correlated well to the potential well inferred from the ion oscillation frequency for both hydrogen and argon experiments. It was found that the timescale for ion oscillation dispersion is strongly dependent on the neutral gas density, and weakly dependent on the peak anode voltage. The cessation of the oscillations was found to be due to charge exchange processes converting ions to high velocity neutrals, causing the abrupt de-coherence of the oscillations through an avalanche dispersion in phase space.

  10. Spherical ion oscillations in a positive polarity gridded inertial-electrostatic confinement device

    Energy Technology Data Exchange (ETDEWEB)

    Bandara, R.; Khachan, J. [Plasma Physics, School of Physics, University of Sydney, Camperdown, New South Wales 2006 (Australia)

    2013-07-15

    A pulsed, positive polarity gridded inertial electrostatic confinement device has been investigated experimentally, using a differential emissive probe and potential traces as primary diagnostics. Large amplitude oscillations in the plasma current and plasma potential were observed within a microsecond of the discharge onset, which are indicative of coherent ion oscillations about a temporarily confined excess of recirculating electron space charge. The magnitude of the depth of the potential well in the established virtual cathode was determined using a differential emissive Langmuir probe, which correlated well to the potential well inferred from the ion oscillation frequency for both hydrogen and argon experiments. It was found that the timescale for ion oscillation dispersion is strongly dependent on the neutral gas density, and weakly dependent on the peak anode voltage. The cessation of the oscillations was found to be due to charge exchange processes converting ions to high velocity neutrals, causing the abrupt de-coherence of the oscillations through an avalanche dispersion in phase space.

  11. Investigation of oscillations of piezoelectric actuators with multi-directional polarization

    Science.gov (United States)

    Lucinskis, Raimundas; Mazeika, Dalius; Bansevicius, Ramutis

    2018-01-01

    Oscillations of two beam type piezoelectric actuators with non-homogeneous polarization are investigated. 3DOF oscillations of the contact point are excited applying harmonic signal on the electrodes of the actuators. Elliptical motion of the contact point is generated in the three perpendicular planes independently. Investigated actuators can move or rotate slider in three different directions. Superposition of flexural resonant oscillations in two perpendicular directions and longitudinal resonant oscillation of the beam is employed to obtain elliptical motion of the contact point. Performed investigation demonstrates that the piezoelectric actuators with non-homogeneous polarization provide an effective solution for generation a multi-DOF motion of the contact point. Both proposed actuators have specific topology of the electrodes that allows to control contact point trajectory by means of particular excitation regimes. The paper presents results of numerical modeling as well as experimental study obtained in the course of testing of the fabricated prototypes of the actuators.

  12. Electric field induced spin polarization oscillation in nonmagnetic benzene/Cu(100) interface: First principles calculations

    Science.gov (United States)

    Yuan, X. B.; Cai, L. L.; Tian, Y. L.; Hu, G. C.; Ren, J. F.

    2018-01-01

    First-principles calculation are presented to study the influences of external electric fields on the spin polarization properties of benzene/Cu(100) system which do not contain any magnetic atom. Our simulations show that an obvious spontaneous spin polarization oscillation occurred in the benzene molecule when the electric fields are applied. The density of states (DOS), spin density distributions, charge transfer properties are also obtained. It is found that the p-d orbital coupling between the benzene molecule and the electrode leads to spin non-degeneration of the DOS near the fermi energy, so the transferred charges from the Cu atoms to the molecule will fill these spin non-degenerate coupled orbitals, and then the benzene molecule becomes spin polarized. The strength of the p-d orbital coupling as well as the transferred charges oscillated with the external electric fields, which induce spin polarization oscillation. The results are favorable for the understanding of spin polarization properties in organic/nonmagnetic metal structures.

  13. Polarization quantum properties in a type-II optical parametric oscillator below threshold

    International Nuclear Information System (INIS)

    Zambrini, Roberta; Miguel, Maxi San; Gatti, Alessandra; Lugiato, Luigi

    2003-01-01

    We study the far-field spatial distribution of the quantum fluctuations in the transverse profile of the output light beam generated by a type-II optical parametric oscillator below threshold, including the effects of transverse walk-off. We study how quadrature field correlations depend on the polarization. We find spatial Einstein-Podolsky-Rosen entanglement in quadrature-polarization components. For the far-field points not affected by walk-off there is almost complete noise suppression in the proper quadratures difference of any orthogonal polarization components. We show the entanglement of the state of symmetric, intense, or macroscopic, spatial light modes. We also investigate nonclassical polarization properties in terms of the Stokes operators. We find perfect correlations in all Stokes parameters measured in opposite far-field points in the direction orthogonal to the walk-off, while locally the field is unpolarized and we find no polarization squeezing

  14. Frequency-driven quantum oscillations in a graphene layer under circularly polarized ac fields

    Energy Technology Data Exchange (ETDEWEB)

    Vega Monroy, R., E-mail: ricardovega@mail.uniatlantico.edu.co; Martinez Castro, O.; Salazar Cohen, G.

    2015-06-19

    In this paper we predict a new type of quantum oscillations driven by the frequency of a circularly polarized ac field in a monolayer of graphene placed inside an optical cavity. We show that the displacement of the structure of photon-dressed electron states near the Fermi level and the electron transitions, from extended states to bound photon-dressed electron states inside an energy gap, lead to a periodic change of singularities in the electron density of states, resulting in quantum oscillations in thermodynamic, transport and other properties in graphene.

  15. Observations of Rabi oscillations in a non-polar InGaN quantum dot

    International Nuclear Information System (INIS)

    Reid, Benjamin P. L.; Chan, Christopher C. S.; Taylor, Robert A.; Kocher, Claudius; Zhu, Tongtong; Oehler, Fabrice; Emery, Robert; Oliver, Rachel A.

    2014-01-01

    Experimental observation of Rabi rotations between an exciton excited state and the crystal ground state in a single non-polar InGaN quantum dot is presented. The exciton excited state energy is determined by photoluminescence excitation spectroscopy using two-photon excitation from a pulsed laser. The population of the exciton excited state is seen to undergo power dependent damped Rabi oscillations.

  16. Rogue waves driven by polarization instabilities in a long ring fiber oscillator

    Science.gov (United States)

    Kolpakov, S. A.; Kbashi, Hani; Sergeyev, Sergey

    2017-05-01

    We present an experimental and theoretical results of a study of a complex nonlinear polarization dynamics in a passively self-mode-locked erbium-doped fiber oscillator implemented in a ring configuration and operating near lasing threshold. The theoretical model consists of seven coupled non-linear equations and takes into account both orthogonal states of polarizations in the fiber. The experiment confirmed the existence of seven eigenfrequencies, predicted by the model due to polarization instability near lasing threshold. By adjusting the state of polarization of the pump and in-cavity birefringence we changed some eigenfrequencies from being different (non-degenerate state) to matching (degenerate state). The non-degenerate states of oscillator lead to the L-shaped probability distribution function and true rogue wave regime with a positive dominant Lyapunov exponent value between 1.4 and 2.6. Small detuning from partially degenerate case also leads to L-shaped probability distribution function with the tail trespassing eight standard deviations threshold, giving periodic patterns of pulses along with positive dominant Lyapunov exponent of a filtered signal between 0.6 and 3.2. The partial degeneration, in turn, guides to quasi-symmetric distribution and the value of dominant Lyapunov exponent of 42 which is a typical value for systems with a source of the strongly nonhomogeneous external noise.

  17. Long-term simulations of polar motion: Variations of the Chandler oscillation over two centuries

    Science.gov (United States)

    Kirschner, Stephanie; Reinwald, Michael; Schmidt, Michael

    2014-05-01

    The Earth Rotation Parameters (ERP) polar motion and length-of-day have been observed with very high precision using space-geodetic techniques over many decades. Temporal changes of ERP on various temporal scales are directly connected with geophysical processes in the Earth system. Here we focus on long-term changes of polar motion, in particular on the development of the Chandler oscillation over a time-frame of two centuries. The study will be performed using five equiprobable ensemble runs of the consistently coupled atmosphere-hydrosphere model ECOCTH (1860-2060). Five respective long-term simulations with the Dynamic Model for Earth Rotation (DyMEG) result in five realizations of the Chandler oscillation. These will be analyzed for similarities and differences using different statistical methods and tools of signal analysis, e.g. wavelets. Furthermore it will be studied in which way the long time series of polar motion reflect effects of climate change as described by ECOCTH.

  18. Eclipse Observations of Coronal Structure, Polarization, and Oscillations from 11 August 1999

    Science.gov (United States)

    Pasachoff, J. M.; Babcock, B. A.; Russell, K. D.; May, S. K.

    2000-05-01

    We report on CCD observations of the corona from Ramnicu Valcea, Romania, during the total solar eclipse of 11 August 1999. One experiment searched for oscillations in the 530.3-nm coronal green line at about 1 Hz by digitizing at 10 Hz, as a determination of the coronal oscillation spectrum to test models of magnetohydrodynamic heating. The optical system was improved in several ways since the 1998 expedition, as was monitoring of the filter. The series of images was aligned and Fourier transforms were examined for individual pixels and groups of pixels. No oscillations were clearly detected above the 1% level, though statistical analysis continues at this writing. A second experiment took a series of 36 images through one filter wheel that contained three filters near 400 nm and a second filter wheel containing polarizers at three angles plus a parfocal clear filter. The results include a polarization map of a quadrant of the sun and an attempt to map the coronal temperature. The temperature map uses techniques suggested by Cram (1976) through a determination of the extent to which scattering off high-temperature electrons wash out the photospheric Fraunhofer lines. Low-pass filtering of our resultant images show detail in the form of coronal loops but do not show much non-radial structure in the temperature variations. We also compare composite photographic observations with EIT images from eclipse day. The expedition was supported by NSF grant ATM-9812408, National Geographic Society grant 6449-99, the Keck Northeast Astronomy Consortium, and NASA SOHO/EIT guest-investigator grant NRA-98-03-SEC-051.

  19. Semiannual Report to Congress

    Data.gov (United States)

    Social Security Administration — The semiannual report includes the recent achievements of OIG's offices such as audit reports, investigations, and cases involving violations of sections 1129 and...

  20. Role of polarizer-tilting-angle in zero-field spin-transfer nano-oscillators with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Fuentes, C.; Gallardo, R. A., E-mail: rodolfo.gallardo@usm.cl; Landeros, P. [Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123 Valparaíso (Chile)

    2015-10-05

    An analytical model for studying the stability of a single domain ferromagnetic layer under the influence of a spin-polarized current is presented. The theory is applied to bias-field-free nano-oscillators with perpendicular anisotropy, which allows to obtain a polarizer-angle vs. current phase diagram that describes the stability of magnetic states. Explicit formulae for the critical current densities unveil the influence of the relative orientation between free and polarizer layers, allowing the emergence of precessional steady-states, and also the possibility to reduce the magnitude of the threshold current density to produce microwave oscillations. It is shown that oscillating steady-states arise in a broad angular region, and the dependence of their boundaries is fully specified by the model. The reliability of the analytical results has been corroborated by comparison to numerical calculations. Such structures are currently under intense research because of remarkable properties offering new prospects for microwave applications in communication technologies.

  1. Zero-field spin transfer oscillators based on magnetic tunnel junction having perpendicular polarizer and planar free layer

    Directory of Open Access Journals (Sweden)

    Bin Fang

    2016-12-01

    Full Text Available We experimentally studied spin-transfer-torque induced magnetization oscillations in an asymmetric MgO-based magnetic tunnel junction device consisting of an in-plane magnetized free layer and an out-of-plane magnetized polarizer. A steady auto-oscillation was achieved at zero magnetic field and room temperature, with an oscillation frequency that was strongly dependent on bias currents, with a large frequency tunability of 1.39 GHz/mA. Our results suggest that this new structure has a high potential for new microwave device designs.

  2. Quasi-periodic oscillations from post-shock accretion column of polars

    Science.gov (United States)

    Bera, Prasanta; Bhattacharya, Dipankar

    2018-02-01

    A set of strongly magnetized accreting white dwarfs (polars) shows quasi-periodic oscillations (QPOs) with frequency about a Hz in their optical luminosity. These Hz-frequency QPOs are thought to be generated by intensity variations of the emitted radiation originating at the post-shock accretion column. Thermal instability in the post-shock region, triggered by efficient cooling process at the base, is believed to be the primary reason behind the temporal variability. Here, we study the structure and the dynamical properties of the post-shock accretion column including the effects of bremsstrahlung and cyclotron radiation. We find that the presence of significant cyclotron emission in optical band reduces the overall variability of the post-shock region. In the case of a larger post-shock region above the stellar surface, the effects of stratification due to stellar gravity become important. An accretion column, influenced by the strong gravity, has a smaller variability as the strength of the thermal instability at the base of the column is reduced. On the other hand, the cool, dense plasma, accumulated just above the stellar surface, may enhance the post-shock variability due to the propagation of magnetic perturbations. These characteristics of the post-shock region are consistent with the observed properties of V834 Cen and in general with cataclysmic variable sources that exhibit QPO frequency of about a Hz.

  3. High-power all fiber-integrated linearly polarized picosecond ytterbium-doped master-oscillator power amplifier

    Science.gov (United States)

    Hong, Chang; Liu, Jiang; Sun, Ruoyu; Shi, Yuhang; Wang, Yu; Wang, Pu

    2018-01-01

    We demonstrated an all-fiber-integrated linearly-polarized picosecond ytterbium-doped master-oscillator power-amplifier system, which yielded 225-W of average output power and the corresponding slope efficiency is 70.5%. The seed source was a compact passively mode-locked polarization-maintaining ytterbium-doped all-fiber oscillator with a pulse duration of 80-ps at 58.2-MHz repetition rate. In combination with two pre-amplifiers and a large-mode-area polarization-maintaining ytterbium-doped all-fiber master amplifier, output pulse energy up to 3.8-μJ with 48.3-kW pulse peak power was obtained without the need of complex free-space coupling and output setups. The polarization extinction ratio were measured to be 14.5 dB and the beam quality M2 factors was less than 1.49 in the both orthogonal directions at maximum output power.

  4. Stratospheric warmings - The quasi-biennial oscillation Ozone Hole in the Antarctic but not the Arctic - Correlations between the Solar Cycle, Polar Temperatures, and an Equatorial Oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Ulf-Peter

    2010-05-15

    This report is a tutorial and overview over some of the complex dynamic phenomena in the polar and equatorial stratosphere, and the unexpected correlation that exists between these and the solar cycle. Sudden stratospheric warmings (stratwarms) occur in the polar stratosphere in winter, but not equally distributed between the two hemispheres. As a result, the ozone hole in the springtime polar stratosphere is much more severe in the Southern Hemisphere than in the Northern Hemisphere. The Quasi-Biennial Oscillation (QBO) is a dynamic phenomenon of the equatorial stratosphere. Through processes not fully understood, the phase of the QBO (easterly or westerly) influences the onset of stratwarms. In addition, a correlation between the stratospheric winter temperature over the poles and the solar cycle has been found, but only if the datapoints are ordered by the phase of the QBO. - The best explanations and figures from four recent textbooks are selected, and abstracts of most relevant publications from the six last years are collected, with the most relevant portions for these subjects highlighted. - In addition to being basic science, the understanding of these phenomena is important in the context of the ozone hole, the greenhouse effect, as well as anthropogenic and natural climate change. (author)

  5. Federal Reserve System Semiannual Regulatory Agenda

    Science.gov (United States)

    2010-12-20

    ... [The Regulatory Plan and Unified Agenda of Federal Regulatory and Deregulatory Actions] [Federal Reserve System Semiannual Regulatory Agenda ] Part XXI Federal Reserve System Semiannual Regulatory Agenda... Flexibility Agenda AGENCY: Board of Governors of the Federal Reserve System. ACTION: Semiannual regulatory...

  6. Jordan Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization

    Science.gov (United States)

    Mota, R. D.; Xicoténcatl, M. A.; Granados, V. D.

    2004-02-01

    In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown a priori. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman matrices of the SU(3) symmetry group. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that the generalized Stokes operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical 3D isotropic harmonic oscillator we describe the geometrical properties of the polarization ellipse.

  7. Jordan-Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization

    Energy Technology Data Exchange (ETDEWEB)

    Mota, R D [Unidad Profesional Interdisciplinaria de IngenierIa y TecnologIas Avanzadas, IPN. Av. Instituto Politecnico Nacional 2580, Col. La Laguna Ticoman, 07340 Mexico DF (Mexico); Xicotencatl, M A [Departamento de Matematicas del Centro de Investigacion y Estudios Avanzados del IPN, Mexico DF, 07000 (Mexico); Granados, V D [Escuela Superior de FIsica y Matematicas, Instituto Politecnico Nacional, Ed. 9, Unidad Profesional Adolfo Lopez Mateos, 07738 Mexico DF (Mexico)

    2004-02-20

    In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown a priori. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman matrices of the SU(3) symmetry group. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that the generalized Stokes operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical 3D isotropic harmonic oscillator we describe the geometrical properties of the polarization ellipse.

  8. Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror

    Science.gov (United States)

    Li, Steven

    2011-01-01

    A laser cavity was designed and implemented by using a wedged polarization rotator and a Porro prism in order to reduce the parts count, and to improve the laser reliability. In this invention, a z-cut quartz polarization rotator is used to compensate the wavelength retardance introduced by the Porro prism. The polarization rotator rotates the polarization of the linear polarized beam with a designed angle that is independent of the orientation of the rotator. This unique property was used to combine the retardance compensation and a Risley prism to a single optical component: a wedged polarization rotator. This greatly simplifies the laser alignment procedure and reduces the number of the laser optical components.

  9. Phase- and Polarization-Controlled Two-Photon Rabi Oscillation of the Biexciton State in a Semiconductor Quantum Dot

    Directory of Open Access Journals (Sweden)

    Erlin Sun

    2014-01-01

    Full Text Available Under a degenerate two-photon resonant excitation, the Rabi oscillation of the four-level biexciton system in a semiconductor quantum dot is theoretically investigated. The influence of the laser phases on the state manipulation is modeled and numerically calculated. Due to the interference between different excitation paths, the laser phase plays an important role and can be utilized as an alternate control knob to coherently manipulate the biexciton state. The phase control can be facilely implemented by changing the light polarization via a quarter-wave plate.

  10. Contributions from Different Sources to Semiannual Variation of Geomagnetic Activity

    Science.gov (United States)

    Lyatskaya, S.; Lyatsky, W.; Tan, A.

    2005-05-01

    Historically, the three possible causes for semiannual variation of geomagnetic activity were proposed: 1) an inclination of the ecliptic plane to the solar equatorial plane (while moving around the Sun, the Earth attains its highest heliospheric latitudes, where solar wind speed increases, in equinoctial months); 2) the semiannual variation of the angle between the Earth's axis and the y-axis in the solar-ecliptic (SE) coordinate system (this angle attains its minimum in equinoctial months that results in increasing the contribution from IMF By in the SE coordinate system to IMF Bz in the solar-magnetospheric coordinate system, which is responsible for geomagnetic activity; this effect is known as the Russell-McPherron effect); and 3) the semiannual variation of solar luminosity of high-latitude conjugate ionospheres (in summer-winter months one of the polar caps is in sunlit conditions while in equinoxes both nightside high-latitude ionospheres are in darkness that is favor for the generation of substorm activity). The last mechanism is not dependent on solar wind conditions while two first mechanisms are dependent. This allowed us to estimate the contributions from these two possible mechanisms to the semiannual variation of geomagnetic activity. For this purpose we investigated the semiannual variation of the Dst index for ten years, 1995-2004. We found that after exclusion of the first mechanism, the amplitude decreases by less than 10%, after excluding the second mechanisms (the Russell-McPherron effect) the amplitude of the semiannual variation decreases by ~ 20%. Although both dependence of solar wind speed on heliospheric latitude and the Russell-McPherron effect are evidently seen in the data, our study showed that these effects contribute in total to the semiannual variation of Dst index not more than 30%.

  11. Climatic impact of glacial cycle polar motion: Coupled oscillations of ice sheet mass and rotation pole position

    Science.gov (United States)

    Bills, Bruce G.; James, Thomas S.; Mengel, John G.

    1999-01-01

    Precessional motion of Earth's rotation axis relative to its orbit is a well-known source of long-period climatic variation. It is less well appreciated that growth and decay of polar ice sheets perturb the symmetry of the global mass distribution enough that the geographic location of the rotation axis will change by at least 15 km and possibly as much as 100 km during a single glacial cycle. This motion of the pole will change the seasonal and latitudinal pattern of temperatures. We present calculations, based on a diurnal average energy balance, which compare the summer and winter temperature anomalies due to a 1° decrease in obliquity with those due to a 1° motion of the rotation pole toward Hudson Bay. Both effects result in peak temperature perturbations of about 1° Celsius. The obliquity change primarily influences the amplitude of the seasonal cycle, while the polar motion primarily changes the annual mean temperatures. The polar motion induced temperature anomaly is such that it will act as a powerful negative feedback on ice sheet growth. We also explore the evolution of the coupled system composed of ice sheet mass and pole position. Oscillatory solutions result from the conflicting constraints of rotational and thermal stability. A positive mass anomaly on an otherwise featureless Earth is in rotational equilibrium only at the poles or the equator. The two polar equilibria are rotationally unstable, and the equatorial equilibrium, though rotationally stable, is thermally unstable. We find that with a plausible choice for the strength of coupling between the thermal and rotational systems, relatively modest external forcing can produce significant response at periods of 104–106 years, but it strongly attenuates polar motion at longer periods. We suggest that these coupled oscillations may contribute to the observed dominance of 100 kyr glacial cycles since the mid-Pleistocene and will tend to stabilize geographic patterns that are suitable to

  12. Potential oscillations and S-shaped polarization curve in the continuous electro-oxidation of CO on platinum single-crystal electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Koper, Marc T.M.; Schmidt, Thomas J.; Markovic, Nenad M.; Ross, Philip N.

    2001-03-01

    The occurrence of an S-shaped polarization curve in a simple model for the continuous electrochemical oxidation of CO on a platinum electrode is discussed. In the model, the S-shaped polarization curve is caused by the competitive Langmuir-Hinshelwood mechanism between surface-bonded CO and OH. The reaction is studied experimentally on single-crystal platinum rotating disk electrodes in perchloric and sulfuric acid solution, and it is shown that the voltammetry is in good agreement with the model predictions. When studied under current-controlled conditions, a fast galvanodynamic scan indeed suggests the existence of the S-shaped polarization curve. At lower scan rates, however, irregularities and small-amplitude irregular fluctuations or oscillations in potential are observed. Very regular potential oscillations under current-controlled conditions are observed only on Pt(111) in sulfuric acid. The possible origin of these irregularities and oscillations is discussed in relation to the existing theories of electrochemical instabilities.

  13. High-performance gap-closing vibrational energy harvesting using electret-polarized dielectric oscillators

    Science.gov (United States)

    Feng, Yue; Yu, Zejie; Han, Yanhui

    2018-01-01

    In conventional gap-closing electret-biased electrostatic energy harvesting (EEEH) schemes, electrets with a very low ratio of electret thickness to permittivity are in great demand to allow the attainment of high power output. However, in practice, pursuing such a low ratio introduces unwanted burdens on the electret stability and therefore the reliability of the EEEH devices. In this paper, we propose a dielectric-oscillator-based electrostatic EH (DEEH) scheme as an alternative approach to harvesting electret-biased electrostatic energy. This approach permits the fabrication of an electret-free closed EH circuit. The DEEH architecture directly collects the electrical energy exclusively through the oscillating dielectric body and thus completely circumvents the restrictions imposed by the electret parameters (thickness and permittivity) on power generation. Significantly, without considering the electret thickness and permittivity, both theoretical analysis and experiments have verified the effectiveness of this DEEH strategy, and a high figure of merit (on the order of 10-8 mW cm-2 V-2 Hz-1) was achieved for low-frequency movements.

  14. Sub-100 fs pulses from an all-polarization maintaining Yb-fiber oscillator with an anomalous dispersion higher-order-mode fiber

    DEFF Research Database (Denmark)

    Verhoef, A. J.; Zhu, L.; Israelsen, Stine Møller

    2015-01-01

    We present an Yb-fiber oscillator with an all-polarizationmaintaining cavity with a higher-order-mode fiber for dispersion compensation. The polarization maintaining higher order mode fiber introduces not only negative second order dispersion but also negative third order dispersion in the cavity...

  15. 75 FR 21955 - Semiannual Regulatory Agenda

    Science.gov (United States)

    2010-04-26

    ... Part XXI National Credit Union Administration ###Semiannual Regulatory Agenda### [[Page 21956... Regulatory Agenda AGENCY: National Credit Union Administration (NCUA). ACTION: Semiannual regulatory agenda... included in the Unified Agenda of Federal Regulatory and Deregulatory Actions. DATES: This information is...

  16. Quantum Drude oscillator model of atoms and molecules: Many-body polarization and dispersion interactions for atomistic simulation

    Science.gov (United States)

    Jones, Andrew P.; Crain, Jason; Sokhan, Vlad P.; Whitfield, Troy W.; Martyna, Glenn J.

    2013-04-01

    Treating both many-body polarization and dispersion interactions is now recognized as a key element in achieving the level of atomistic modeling required to reveal novel physics in complex systems. The quantum Drude oscillator (QDO), a Gaussian-based, coarse grained electronic structure model, captures both many-body polarization and dispersion and has linear scale computational complexity with system size, hence it is a leading candidate next-generation simulation method. Here, we investigate the extent to which the QDO treatment reproduces the desired long-range atomic and molecular properties. We present closed form expressions for leading order polarizabilities and dispersion coefficients and derive invariant (parameter-free) scaling relationships among multipole polarizability and many-body dispersion coefficients that arise due to the Gaussian nature of the model. We show that these “combining rules” hold to within a few percent for noble gas atoms, alkali metals, and simple (first-row hydride) molecules such as water; this is consistent with the surprising success that models with underlying Gaussian statistics often exhibit in physics. We present a diagrammatic Jastrow-type perturbation theory tailored to the QDO model that serves to illustrate the rich types of responses that the QDO approach engenders. QDO models for neon, argon, krypton, and xenon, designed to reproduce gas phase properties, are constructed and their condensed phase properties explored via linear scale diffusion Monte Carlo (DMC) and path integral molecular dynamics (PIMD) simulations. Good agreement with experimental data for structure, cohesive energy, and bulk modulus is found, demonstrating a degree of transferability that cannot be achieved using current empirical models or fully ab initio descriptions.

  17. Efficient high-pulse-energy eye-safe laser generated by an intracavity Nd:YLF/KTP optical parametric oscillator: role of thermally induced polarization switching

    International Nuclear Information System (INIS)

    Huang, Y J; Tang, C Y; Huang, Y P; Cho, C Y; Su, K W; Chen, Y F

    2012-01-01

    A high-pulse-energy eye-safe laser at 1552 nm is effectually generated by an intracavity Nd:YLF/KTP optical parametric oscillator (OPO) with the help of the thermally induced polarization switching. The polarization characteristics of the c-cut Nd:YLF laser at 1053 nm in the continuous-wave (CW) and Q-switched operation are comprehensively investigated. We experimentally verify the thermally induced birefringence can lead to a polarization switching between the mutually orthogonal components of the fundamental pulses. Consequently, an efficient intracavity nonlinear frequency conversion can be achieved in an optically isotropic laser crystal without any additional polarization control. With this finding, the pulse energy and peak power of the compact Nd:YLF/KTP eye-safe laser under an incident pump power of 12.7 W and a pulse repetition rate of 5 kHz are up to 306 μJ and 4 kW, respectively

  18. Small Business Administration Semiannual Regulatory Agenda

    Science.gov (United States)

    2010-12-20

    ... represent that it will make good faith efforts to award subcontracts to small businesses at the same... measurement of management and technical assistance projects conducted by Women's Business Center program... Business Administration Semiannual Regulatory Agenda] Part XVII Small Business Administration Semiannual...

  19. Relativistic spin-polarized KKR theory for superconducting heterostructures: Oscillating order parameter in the Au layer of Nb/Au/Fe trilayers

    Science.gov (United States)

    Csire, Gábor; Deák, András; Nyári, Bendegúz; Ebert, Hubert; Annett, James F.; Újfalussy, Balázs

    2018-01-01

    The fully relativistic spin-polarized multiple-scattering theory is developed for inhomogeneous superconductors, including superconducting/normal-metal/ferromagnet heterostructures. The method allows the solution of the first-principles Dirac-Bogoliubov-de Gennes equations combined with a semiphenomenological parametrization of the exchange-correlation functional. Simple conditions are derived for the case when the right-hand-side and left-hand-side solutions must be treated separately when setting up the corresponding Green's function. As an application of the theory, we calculate the order parameters of Nb/Fe and Nb/Au/Fe systems. We find Fulde-Ferrell-Larkin-Ovchinnikov-like oscillations in the iron layers, but more interestingly an oscillatory behavior is observed in the gold layers as well. The band-structure calculations suggest that this is the consequence of an interplay between the quantum-well states and ferromagnetism.

  20. Effects of atmospheric oscillations on the field-aligned ion motions in the polar F-region

    Directory of Open Access Journals (Sweden)

    S. Oyama

    Full Text Available The field-aligned neutral oscillations in the F-region (altitudes between 165 and 275 km were compared using data obtained simultaneously with two independent instruments: the European Incoherent Scatter (EISCAT UHF radar and a scanning Fabry-Perot interferometer (FPI. During the night of February 8, 1997, simultaneous observations with these instruments were conducted at Tromsø, Norway. Theoretically, the field-aligned neutral wind velocity can be obtained from the field-aligned ion velocity and by diffusion and ambipolar diffusion velocities. We thus derived field-aligned neutral wind velocities from the plasma velocities in EISCAT radar data. They were compared with those observed with the FPI (λ=630.0 nm, which are assumed to be weighted height averages of the actual neutral wind. The weighting function is the normalized height dependent emission rate. We used two model weighting functions to derive the neutral wind from EISCAT data. One was that the neutral wind velocity observed with the FPI is velocity integrated over the entire emission layer and multiplied by the theoretical normalized emission rate. The other was that the neutral wind velocity observed with the FPI corresponds to the velocity only around an altitude where the emission rate has a peak. Differences between the two methods were identified, but not completely clarified. However, the neutral wind velocities from both instruments had peak-to-peak correspondences at oscillation periods of about 10–40 min, shorter than that for the momentum transfer from ions to neutrals, but longer than from neutrals to ions. The synchronizing motions in the neutral wind velocities suggest that the momentum transfer from neutrals to ions was thought to be dominant for the observed field-aligned oscillations rather than the transfer from ions to neutrals. It is concluded that during the observation, the plasma oscillations observed with the EISCAT radar at different altitudes

  1. Precessing deuteron polarization

    International Nuclear Information System (INIS)

    Sitnik, I.M.; Volkov, V.I.; Kirillov, D.A.; Piskunov, N.M.; Plis, Yu.A.

    2002-01-01

    The feasibility of the acceleration in the Nuclotron of deuterons polarized in the horizontal plane is considered. This horizontal polarization is named precessing polarization. The effects of the main magnetic field and synchrotron oscillations are included. The precessing polarization is supposed to be used in studying the polarization parameters of the elastic dp back-scattering and other experiments

  2. 76 FR 40200 - Semiannual Regulatory Flexibility Agenda

    Science.gov (United States)

    2011-07-07

    ... Vol. 76 Thursday, No. 130 July 7, 2011 Part XXI Federal Reserve System Semiannual Regulatory Agenda #0;#0;Federal Register / Vol. 76 , No. 130 / Thursday, July 7, 2011 / Unified Agenda#0;#0; [[Page 40200

  3. 75 FR 79863 - Semiannual Regulatory Agenda

    Science.gov (United States)

    2010-12-20

    ... represent that it will make good faith efforts to award subcontracts to small businesses at the same... measurement of management and technical assistance projects conducted by Women's Business Center program... Part XVII Small Business Administration ###Semiannual Regulatory Agenda### [[Page 79864

  4. Polar motion as boundary condition in an adaptive Kalman filter approach for the determination of period and damping of the Chandler oscillation

    Science.gov (United States)

    Seitz, F.; Kirschner, S.; Neubersch, D.

    2012-12-01

    Earth rotation has been monitored using space geodetic techniques since many decades. The geophysical interpretation of observed time series of Earth rotation parameters (ERP) polar motion and length-of-day is commonly based on numerical models that describe and balance variations of angular momentum in various subsystems of the Earth. Naturally, models are dependent on geometrical, rheological and physical parameters. Many of these are weakly determined from other models or observations. In our study we present an adaptive Kalman filter approach for the improvement of parameters of the dynamic Earth system model DyMEG which acts as a simulator of ERP. In particular we focus on the improvement of the pole tide Love number k2. In the frame of a sensitivity analysis k2 has been identified as one of the most crucial parameters of DyMEG since it directly influences the modeled Chandler oscillation. At the same time k2 is one of the most uncertain parameters in the model. Our simulations with DyMEG cover a period of 60 years after which a steady state of k2 is reached. The estimate for k2, accounting for the anelastic response of the Earth's mantle and the ocean, is 0.3531 + 0.0030i. We demonstrate that the application of the improved parameter k2 in DyMEG leads to significantly better results for polar motion than the original value taken from the Conventions of the International Earth Rotation and Reference Systems Service (IERS).

  5. Long-periodic strong radar echoes in the summer polar D region correlated with oscillations of high-speed solar wind streams

    Science.gov (United States)

    Lee, Young-Sook; Kirkwood, Sheila; Shepherd, Gordon G.; Kwak, Young-Sil; Kim, Kyung-Chan

    2013-08-01

    We report long-periodic oscillations of polar mesospheric summer echoes (PMSEs) correlated with high-speed solar wind streams (HSSs) as observed between 1 June and 8 August in the solar minimum years 2006 and 2008. PMSEs (80-90 km altitudes) were observed by 52 MHz VHF radar measurements at Esrange, Sweden (67.8°N, 20.4°E). Correlations between PMSE volume reflectivity/counts, HSSs, and AE index are primarily found at 7-day, 9-day, and 13-day periodicities as well as 9-day and 13.5-day periodicities in 2006 and 2008, respectively. The observations show that the effects of HSSs appear in PMSEs. During corotating interaction region (CIR)-induced HSSs, the long-lasting enhancement of PMSEs, geomagnetic disturbances, and D-region ionization suggests that a favorable condition in generating PMSEs can be provided by the precipitating energetic electrons (>30 keV), which are frequently multiplied in the magnetosphere during HSSs.

  6. Semiannual patents review, July-December 1998

    Science.gov (United States)

    Matthew. Stroika; Marguerite. Sykes; Julie. Blankenburg

    1999-01-01

    This review summarizes patents related to paper recycling issued during the last 6 months of 1998. The two online databases used for this search are Claim/US. Patents Abstracts and Derwent World Patents Index. This semiannual feature is intended to inform readers about the latest developments in equipment, chemicals, and technology in the field of paper recycling. This...

  7. Semiannual patents review, July 2001-December 2001

    Science.gov (United States)

    Roland Gleisner; Marguerite Sykes; Julie Blankenburg

    2002-01-01

    This review summarizes patents related to paper recycling that were issued during the last six months of 2001. Two on-line databases, Claims/U.S. Patents Abstracts and Derwent World Patents Index, were searched for this review. This semiannual feature is intended to inform readers about recent developments in equipment design, chemicals and process technology for...

  8. Semiannual patents review, January-June 1999

    Science.gov (United States)

    Marguerite Sykes; Julie Blankenburg

    1999-01-01

    This review summarizes patents related to paper recycling that were issued during the first 6 months of 1999. The two on-line databases used for this search were C1aims/U.S. Patents Abstracts and Derwent World Patents Index. This semiannual feature is intended to inform readers about the latest developments in equipment design, chemicals, and process technology for...

  9. Semiannual patents review, January — June 2001.

    Science.gov (United States)

    Marguerite S. Sykes; Julie. Blankenburg

    2001-01-01

    This review summarizes patents related to paper recycling that were issued during the first 6 months of 2001. Two online databases, Claims/U.S. Patents Abstracts and Derwent World Patents Index, were searched for this review. This semiannual feature is intended to inform readers about recent developments in equipment design, chemicals, and process technology for...

  10. 76 FR 40136 - Semiannual Regulatory Agenda

    Science.gov (United States)

    2011-07-07

    ... business prime contractor must represent that it will make good faith efforts to award subcontracts to... cases where an award has been made prior to an SBA final decision finding a business to be ineligible... Vol. 76 Thursday, No. 130 July 7, 2011 Part XVI Small Business Administration Semiannual...

  11. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    Directory of Open Access Journals (Sweden)

    L. Moreira

    2016-08-01

    Full Text Available A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m. GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC. The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO, the quasi-biennial oscillation (QBO, the El Niño–Southern Oscillation (ENSO and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose

  12. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    Science.gov (United States)

    Moreira, Lorena; Hocke, Klemens; Navas-Guzmán, Francisco; Eckert, Ellen; von Clarmann, Thomas; Kämpfer, Niklaus

    2016-08-01

    A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is

  13. First semiannual report 1979/1

    International Nuclear Information System (INIS)

    1980-02-01

    The 15th semi-annual report 1979/1 is a description of work within the Nuclear Safety Project performed in the first six month of 1979 in the nuclear safety field by KfK institutes and departments and by external institutions on behalf of KfK. The chosen kind of this report is that of short summaries, containing the topics: - work performed, results obtained, plans for future work. This report was compiled by the project management. (orig.) [de

  14. Numerical calculations of the absorption and oscillation processes in the nonlinear polarized crystal Cr4+:YAG pumped by Nd-glass laser

    International Nuclear Information System (INIS)

    Abdul Ghani, B.; Hammadi, M.

    2007-01-01

    A mathematical model describing the dynamic emission of intracavity isotropic Cr 4+ : YAG polarized solid-state saturable absorber as a tool of dual Q-switching and lasing processes 1.06 μm and 1.4 μm by double pumping pulse has been developed. This model describes the time evolution of interaction between the pumping laser pulse with a changed polarization state and the polarized absorber. (author)

  15. The Thermospheric Semiannual Density Response to Solar EUV Heating

    Science.gov (United States)

    2008-01-01

    Keystone, CO. Cook, G.E., 1969. The semi-annual variation in the upper atmosphere: a review. Annales de Geophysique 25, 451. Jacchia, L.G., 1966. Density...variations in the heterosphere. Annales de Geophysique 22, 75. Jacchia, L.G., 1971a. Semiannual variation in the heterosphere: a reappraisal. Journal

  16. 77 FR 25523 - Semi-Annual Workforce Management Conference

    Science.gov (United States)

    2012-04-30

    ... focus on the need for a future workforce with solid foundations in the STEM disciplines, best practices... Office of the Secretary Semi-Annual Workforce Management Conference AGENCY: U.S. Department of... of Transportation, Office of the Secretary, announces the second Semi-Annual Workforce Management...

  17. Annual and semiannual variations of the cosmic radiation

    International Nuclear Information System (INIS)

    Khor, H.P.; Kwok, W.K.; Owens, A.J.

    1979-01-01

    We determine the annual and semiannual harmonics in the Deep River Neutron Monitor counting rate for the years 1960--1975. A new Fourier analysis technique is used to eliminate solar cycle variations, an we discuss the statistical errors in the determination of the harmonics. The annual and semiannual waves changed markedly from year to year. The yearly harmonic has an average amplitude approx.0.6% with a maximum in early March, corresponding to a southward anisotropy of approx.5%/AU perpendicular to the solar equatorial plane. The semiannual harmonic shows no phase coherence and its average amplitude is only marginally significant, < or approx. =0.2%

  18. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  19. Neurodynamic oscillators

    Science.gov (United States)

    Espinosa, Ismael; Gonzalez, Hortensia; Quiza, Jorge; Gonazalez, J. Jesus; Arroyo, Ruben; Lara, Ritaluz

    1995-01-01

    Oscillation of electrical activity has been found in many nervous systems, from invertebrates to vertebrates including man. There exists experimental evidence of very simple circuits with the capability of oscillation. Neurons with intrinsic oscillation have been found and also neural circuits where oscillation is a property of the network. These two types of oscillations coexist in many instances. It is nowadays hypothesized that behind synchronization and oscillation there is a system of coupled oscillators responsible for activities that range from locomotion and feature binding in vision to control of sleep and circadian rhythms. The huge knowledge that has been acquired on oscillators from the times of Lord Rayleigh has made the simulation of neural oscillators a very active endeavor. This has been enhanced with more recent physiological findings about small neural circuits by means of intracellular and extracellular recordings as well as imaging methods. The future of this interdisciplinary field looks very promising; some researchers are going into quantum mechanics with the idea of trying to provide a quantum description of the brain. In this work we describe some simulations using neuron models by means of which we form simple neural networks that have the capability of oscillation. We analyze the oscillatory activity with root locus method, cross-correlation histograms, and phase planes. In the more complicated neural network models there is the possibility of chaotic oscillatory activity and we study that by means of Lyapunov exponents. The companion paper shows an example of that kind.

  20. 31 CFR 359.11 - What is the semiannual inflation rate?

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false What is the semiannual inflation rate... BONDS, SERIES I General Information § 359.11 What is the semiannual inflation rate? The index used to determine the semiannual inflation rate is the non-seasonally adjusted CPI-U (the Consumer Price Index for...

  1. Neutrino Oscillations

    Indian Academy of Sciences (India)

    Neutrino Oscillations: New Windows to the Particle World. General Article Volume 21 Issue 10 ... Neutrino oscillation is a quantum mechanicalphenomenon whereby a neutrino created witha specific lepton flavour (electron, muon, or tau) can later bemeasured to have a different flavour. Historical developmentof the field in ...

  2. Chemical Oscillations

    Indian Academy of Sciences (India)

    The law of mass-action led chemists to the belief that reactions approach equilibrium steadily. So the discovery of chemical oscillations came as a surprise. Now chemists are very familiar with reactions that oscillate in time and/or space. Experimental and theoretical studies of such reac- tions showing temporal and spatial ...

  3. 75 FR 21749 - Spring 2010 Semiannual Agenda of Regulations

    Science.gov (United States)

    2010-04-26

    ... Chs. II, III, IV, and VI Spring 2010 Semiannual Agenda of Regulations AGENCY: Office of the Secretary... (Department), in the spring and fall of each year, publishes in the Federal Register an agenda of regulations... and views by interested members of the public. The Department's spring 2010 regulatory agenda includes...

  4. 2. Semi-annual progress report 1980, no 17

    International Nuclear Information System (INIS)

    1981-01-01

    This semi-annual report deals with the experimental research carried out at the Departement de Recherche Fondamentale de Grenoble (fission, nuclear spectroscopy, heavy ion reactions, physical metallurgy, magnetism, organic molecules, theoretical chemistry, molecular physical chemistry, cellular biology, vegetal biology) [fr

  5. Semiannual patents review July 2002–December 2002

    Science.gov (United States)

    Roland Gleisner; Julie Blankenburg

    2003-01-01

    This review summarizes patents related to paper recycling that were issued during the last six months of 2002. Two on-line databases, Claims/U.S. Patents Abstracts and Derwent World Patents Index, were searched for this review. This semiannual feature is intended to inform readers about recent developments in equipment design, chemicals, and process technology for...

  6. 13 CFR 146.600 - Semi-annual compilation.

    Science.gov (United States)

    2010-01-01

    ... Intelligence of the Senate, the Permanent Select Committee on Intelligence of the House of Representatives, and... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Semi-annual compilation. 146.600 Section 146.600 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW RESTRICTIONS ON LOBBYING...

  7. NRC regualtory agenda. Semiannual report, July 1997--December 1997

    International Nuclear Information System (INIS)

    1998-02-01

    The Regulatory Agenda is a semiannual compilation of all rules on which the NRC has recently completed action, or has proposed action, or is considering action, and of all petitions for rulemaking that the NRC has received that are pending disposition

  8. NMR dispersion measurement of dynamic nuclear polarization

    International Nuclear Information System (INIS)

    Davies, K.; Cox, S.F.J.

    1978-01-01

    The feasibility of monitoring dynamic nuclear polarization from the NMR dispersive susceptibility is examined. Two prototype instruments are tested in a polarized proton target using organic target material. The more promising employs a tunnel diode oscillator, inside the target cavity, and should provide a precise polarization measurement working at a frequency far enough from the main resonance for the disturbance of the measured polarization to be negligible. Other existing methods for measuring target polarization are briefly reviewed. (author)

  9. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  10. Chemical Oscillations

    Indian Academy of Sciences (India)

    behaviour of a few complex chemical systems. We observed that these chemical oscillators are basically .... Kutta fourth order integration method to solve the Lotka-. Volterra equation as per the Fortran program given in ... This is known as the phase plane represen- tation. We have obtained these plots using the software.

  11. Chemical Oscillations

    Indian Academy of Sciences (India)

    relevant species is zero. So, oscillations can appear only if the inhibition step is somehow .... the value of such an experimental parameter can possi- bly move the system between the steady states. Per- ... states for different values of [X], obtained far from equilibrium. Figure 2. System showing. The concentrations [X] ...

  12. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  13. Twenty-first Semiannual Report of the Commission to the Congress, January 1957

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1957-01-31

    The document represents the twenty-first semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1956. A special part two of this semiannual report addresses specifically Radiation Safety in Atomic Energy Activities.

  14. Power oscillation damping controller

    DEFF Research Database (Denmark)

    2012-01-01

    A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...... signal in response to the oscillation indicating signal, by processing the oscillation damping control signal in a signal processing chain. The signal processing chain includes a filter configured for passing only signals within a predetermined frequency range....

  15. Oscillations of void lattices

    International Nuclear Information System (INIS)

    Akhiezer, A.I.; Davydov, L.N.; Spol'nik, Z.A.

    1976-01-01

    Oscillations of a nonideal crystal are studied, in which macroscopic defects (pores) form a hyperlattice. It is shown that alongside with acoustic and optical phonons (relative to the hyperlattice), in such a crystal oscillations of the third type are possible which are a hydridization of sound oscillations of atoms and surface oscillations of a pore. Oscillation spectra of all three types were obtained

  16. Polarization-beam-splitter-less integrated dual-polarization coherent receiver.

    Science.gov (United States)

    Alonso-Ramos, C; Reyes-Iglesias, P J; Ortega-Moñux, A; Pérez-Galacho, D; Halir, R; Molina-Fernández, I

    2014-08-01

    Conventional dual-polarization coherent receivers require polarization beam splitters for either the signal or the local oscillator path. This severely hinders monolithic integration, since integrated polarization splitting devices often exhibit stringent fabrication tolerances. Here we propose a dual-polarization monolithically integrated coherent receiver architecture that completely avoids the use of polarization splitting elements. Polarization management is instead achieved by adequately engineering the birefringence of the interconnecting waveguides. The resultant receiver is highly tolerant to fabrication deviations and thus offers a completely new route for monolithic integration of dual-polarization receivers without any type of active tuning.

  17. Monlithic nonplanar ring oscillator and method

    Science.gov (United States)

    Nilsson, Alan C. (Inventor); Byer, Robert L. (Inventor)

    1991-01-01

    A monolithic nonplanar ring oscillator having an optically isotropic solid-state laser body for propagating laser radiation about a nonplanar ring path internal to the laser body is disclosed. The monolithic laser body is configured to produce a 2N reflection nonplanar ring light path, where N is an integer greater than or equal to 2, comprising 2N-1 total internal reflections and one reflection at a coupler in a single round trip. Undirectional traveling wave oscillation of the laser is induced by the geometry of the nonplanar ring path together with the effect of an applied magnetic field and partial polarizer characteristics of the oblique reflection from the coupler. The 6-reflection nonplanar ring oscillator makes possible otpimal unidirectional oscillation (low loss for the oscillating direction of propagation and, simultaneously high loss for the nonoscillating direction of propagation) in monolithic NPROs using materials with index of refraction smaller than the square root of 3, for example, laser glass.

  18. On the spatial pattern of semi-annual signals present in GRACE gravity fields

    Science.gov (United States)

    Naeimi, M.; Mueller, J.

    2009-04-01

    GRACE monthly solutions clearly show mass changes and mass redistribution within the earth. Such variability is due to some known and unknown geophysical and geodynamical processes interacting in the earth system. One way to distinguish between these different sources is to analyze the compound gravity signals in the spectral domain to separate phenomena with different temporal resolutions. Since the launch of GRACE satellites, more than seventy monthly solutions have been released by different processing centers. As the time span of the available data increases, the possibility of significantly detecting signals with extended temporal wavelength will increase, too. In this work, a spectral analysis is performed to the GRACE geoids over the globe and the spatial patterns of some relevant periodicities are shown as well as regions with secular changes. Besides some well known temporal variations like secular changes and annual cycles, our study explicitly shows the existence of semi-annual signals with considerable amplitudes in Nepal and northern India as well as in the Polar Regions. The significance of the signals is discussed and probable explanation will be given as well.

  19. Coherent states with elliptical polarization

    OpenAIRE

    Colavita, E.; Hacyan, S.

    2004-01-01

    Coherent states of the two dimensional harmonic oscillator are constructed as superpositions of energy and angular momentum eigenstates. It is shown that these states are Gaussian wave-packets moving along a classical trajectory, with a well defined elliptical polarization. They are coherent correlated states with respect to the usual cartesian position and momentum operators. A set of creation and annihilation operators is defined in polar coordinates, and it is shown that these same states ...

  20. Semiannual Report of the Chemistry Department, June--November 1966

    International Nuclear Information System (INIS)

    1967-01-01

    This semiannual report of the Chemistry Department of the Cea of Fontenay-aux Roses, presents in its first part researches on the chemical analysis, the treatment of fairly and slightly active effluents, the uranium treatment, studies on electrometallurgy, studies on corrosion and studies on filtration and elimination on sea water of hard compounds. The second part is devoted to the study of aqueous reprocessing of irradiated fuels (laboratory and pilot plant), anhydrous reprocessing, actinides elements isotopes preparation and study, fission products concentrated solution vitrification study and fundamental studies on acid-base properties. (A.L.B.)

  1. Semiannual report on strategic special nuclear material inventory differences

    International Nuclear Information System (INIS)

    1987-07-01

    This twentieth periodic semiannual report of unclassified Inventory Differences (ID's) covers the second six months of fiscal year 1986 (April 1, 1986, through September 30, 1986) for all key Department of Energy (DOE) and DOE contractor operated facilities possessing strategic special nuclear materials. Data for the Rocky Flats and Y-12 nuclear weapons production facilities are not included in the report in order to protect classified nuclear weapons information; however, classified ID data from these facilities receive the same scrutiny and analyses as the unclassified data

  2. Oscillators - a simple introduction

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2013-01-01

    Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?......Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?...

  3. Oscillating Permanent Magnets.

    Science.gov (United States)

    Michaelis, M. M.; Haines, C. M.

    1989-01-01

    Describes several ways to partially levitate permanent magnets. Computes field line geometries and oscillation frequencies. Provides several diagrams illustrating the mechanism of the oscillation. (YP)

  4. POLARIZED NEUTRONS IN RHIC

    Energy Technology Data Exchange (ETDEWEB)

    COURANT,E.D.

    1998-04-27

    There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

  5. Twenty-second Semiannual Report of the Commission to the Congress, July 1957

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1957-07-31

    The document represents the twenty-second semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1957.

  6. Tenth Semiannual Report of the Commission to the Congress, July 1951

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1951-07-01

    The document represents the tenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1951.

  7. Sixteenth Semiannual Report of the Commission to the Congress, July 1954

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1954-07-31

    The document represents the sixteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1954.

  8. Nineteenth Semiannual Report of the Commission to the Congress, January 1956

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1956-01-31

    The document represents the nineteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1955.

  9. Seventeenth Semiannual Report of the Commission to the Congress, January 1955

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1955-01-29

    The document represents the seventeenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1954.

  10. Twentieth Semiannual Report of the Commission to the Congress, July 1956

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1956-07-31

    The document represents the twentieth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1956.

  11. Twenty-fourth Semiannual Report of the Commission to the Congress, July 1958

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.; McCone, John A.

    1958-07-31

    The document represents the twenty-fourth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1958.

  12. Cumulative Index to Twenty Five Semiannual Reports of the Commission to the Congress. January 1947 - January 1959

    Energy Technology Data Exchange (ETDEWEB)

    McCone, John A.

    1960-01-31

    The first twenty five semiannual reports of the United States Atomic Energy Commission to Congress cover the major unclassified activities of the Commission from January 1947 through January 1959. In addition to the semiannual summaries, a series of special reports on important atomic energy programs were included in many of the semiannual reports. This cumulative name and subject index provides a guide to the information published in these reports. Beginning in 1960, the Commission will be issuing annual reports, each separately indexed, ceasing the semiannual reporting.

  13. Investigation of invisible oscillation on the photodetachment cross ...

    Indian Academy of Sciences (India)

    2013-05-28

    May 28, 2013 ... in a static electric field by using pulsed dye-laser beam. (perpendicular to the field). They have reported laser polarization-dependent electric field oscillations in the p-wave detachment cross-section of Au. − near the threshold. The exper- iment support the theory for laser polarizations both parallel and ...

  14. Semiannually alternating exchange of intermediate waters east of the Philippines

    Science.gov (United States)

    Song, Lina

    2017-04-01

    Intermediate water exchange in the northwest tropical Pacific is explored with the temperature, salinity, and current measurements of a mooring system deployed at 8°N, 127.05°E during 2010-2014. For the first time, prominent semiannual variability (SAV; with the maximum power at 187 days) of subthermocline meridional flow along the Mindanao coast is revealed. A significant correlation between meridional flow and salinity is found at intermediate depths. This provides direct evidence for the alternating transports of South Pacific and North Pacific Intermediate Waters by northward and southward undercurrents, respectively. Further analysis with an eddy-resolving ocean general circulation model demonstrates that the SAV is generated locally near the western boundary, manifesting as large-scale subthermocline recirculation and leading to alternating northward and southward flows near the Mindanao coast, which plays an efficient role in the intermediate water exchange of the northwest tropical Pacific. Mechanisms underlying the observed SAV are discussed

  15. Semiannual report to Congress, October 1, 1994--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    The Office of Inspector General Semiannual Report to the Congress covers the period October 1, 1994, through March 31, 1995. The report summarizes significant audit, inspection and investigative accomplishments for the reporting period, a large number of which facilitated Department management`s efforts to improve management controls and ensure efficient and effective operation. Narratives of the most significant reports are grouped by six primary performance measures: (1) Recommendations accepted by management, (2) Audit/inspection savings, recoveries, and funds identified for better use, (3) Legislative/regulatory compliance to recommendations, (4) Positive impacts on the Department after implementation of recommendations, (5) Complaints resolved, and (6) Investigation recoveries, fines, and funds identified for better use.

  16. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  17. Phenomenology of neutrino oscillations

    Indian Academy of Sciences (India)

    Abstract. The phenomenology of solar, atmospheric, supernova and laboratory neutrino oscillations is described. Analytical formulae for matter effects are reviewed. The results from oscillations are confronted with neutrinoless double beta decay.

  18. The colpitts oscillator family

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, A.

    A tutorial study of the Colpitts oscillator family defined as all oscillators based on a nonlinear amplifier and a three- terminal linear resonance circuit with one coil and two capacitors. The original patents are investigated. The eigenvalues of the linearized Jacobian for oscillators based...

  19. Index to the Twenty-first Semiannual Report of the Commission to the Congress. July 1956 - December 1956

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1957-01-31

    This volume contains a name and subject indext for the twenty-first semiannual report of the United States Atomic Energy Commission to Congress. The full semiannual report covers the major unclassified activities of the Commission from July 1956 through December 1956.

  20. Cumulative Index to the Sixteenth through the Twentieth Semiannual Reports of the Commission to the Congress. January 1954 - June 1956

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1956-07-30

    The sixteenth through the twentieth semiannual reports of the United States Atomic Energy Commission to Congress are covered in this cumulative index, which included both a name and subject index as aids to finding information in the full reports.. The full semiannual reports themselves cover the major unclassified activities of the Commission from January 1954 through June 1956.

  1. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  2. Ionospheric F2-Layer Semi-Annual Variation in Middle Latitude by Solar Activity

    Directory of Open Access Journals (Sweden)

    Yoon-Kyung Park

    2010-12-01

    Full Text Available We examine the ionospheric F2-layer electron density variation by solar activity in middle latitude by using foF2 observed at the Kokubunji ionosonde station in Japan for the period from 1997 to 2008. The semi-annual variation of foF2 shows obviously in high solar activity (2000-2002 than low solar activity (2006-2008. It seems that variation of geomagnetic activity by solar activity influences on the semi-annual variation of the ionospheric F2-layer electron density. According to the Lomb-Scargle periodogram analysis of foF2 and Ap index, interplanetary magnetic field (IMF Bs (IMF Bz <0 component, solar wind speed, solar wind number density and flow pressure which influence the geomagnetic activity, we examine how the geomagnetic activity affects the ionospheric F2-layer electron density variation. We find that the semi-annual variation of daily foF2, Ap index and IMF Bs appear clearly during the high solar activity. It suggests that the semi-annual variation of geomagnetic activity, caused by Russell-McPherron effect, contributes greatly to the ionospheric F2-layer semi-annual electron density variation, except dynamical effects in the thermosphere.

  3. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  4. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  5. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  6. Space distribution and cycles yearly and semiannual of the precipitation in Colombia

    International Nuclear Information System (INIS)

    Mejia, Freddy; Mesa, Oscar; Poveda, German; Velez, Jaime; Hoyos, Carlos; Mantilla, Ricardo; Barco, Janet; Cuartas, Adriana; Montoya, Maria; Botero, Blanca

    1999-01-01

    The analyses of Colombia's mean annual rainfall distribution and of its annual and semi-annual cycle shown in this paper is the result of a wider research project on Colombia's water budget. The rainfall map is based upon tropical, rain gage data, maps produced in previous studies, large-scale climatic analysis and various interpolation techniques. Kriging with drift was used for the interpolation of the annual rainfall, taking previous maps as the drift term. For the monthly values ordinary kriging was used. The amplitude and phase of the annual and semi-annual cycle of precipitation was estimated by means of Fourier transform. Annual and semi-annual cycles of precipitation over Colombia reflect the passage of the inter tropical converge zone

  7. A memristor-based third-order oscillator: beyond oscillation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2012-10-06

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  8. A memristor-based third-order oscillator: beyond oscillation

    Science.gov (United States)

    Talukdar, A.; Radwan, A. G.; Salama, K. N.

    2011-09-01

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  9. Third Semiannual Report to the Congress by the United States Atomic Energy Commission, February 2, 1948

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, David E.; Bacher, Robert F.; Pike, Sumner T.; Strauss, Lewis L.; Waymack, William W.

    1948-02-02

    The document includes the letter of submittal and the third semiannual report. These reports are called for pursuant to Section 17 of the Atomic Energy Act of 1946. The letter of submittal was titled ''Letter from the Chairman and Members of the United States Atomic Energy Commission transmitting pursuant to law the third semiannual report of the Atomic Energy Commission''. It was authored by David E. Lilienthal, Chairman, and Robert F. Bacher, Sumner T. Pike, Lewis L. Strauss, and William W. Waymack of the AEC.

  10. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  11. Oscillations of disks

    CERN Document Server

    Kato, Shoji

    2016-01-01

    This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

  12. Self-oscillation

    Science.gov (United States)

    Jenkins, Alejandro

    2013-04-01

    Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain dynamical systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy into the vibration: no external rate needs to be adjusted to the resonant frequency. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the swaying of the London Millennium Footbridge in 2000. Clocks are self-oscillators, as are bowed and wind musical instruments. The heart is a “relaxation oscillator”, i.e., a non-sinusoidal self-oscillator whose period is determined by sudden, nonlinear switching at thresholds. We review the general criterion that determines whether a linear system can self-oscillate. We then describe the limiting cycles of the simplest nonlinear self-oscillators, as well as the ability of two or more coupled self-oscillators to become spontaneously synchronized (“entrained”). We characterize the operation of motors as self-oscillation and prove a theorem about their limit efficiency, of which Carnot’s theorem for heat engines appears as a special case. We briefly discuss how self-oscillation applies to servomechanisms, Cepheid variable stars, lasers, and the macroeconomic business cycle, among other applications. Our emphasis throughout is on the energetics of self-oscillation, often neglected by the literature on nonlinear dynamical systems.

  13. Phenomenology of neutrino oscillations

    Indian Academy of Sciences (India)

    In this talk, I shall try to give a bird's eye view of the current status of neutrino oscillations. ..... the night effect. An asymmetry between the night and day rates would be an unambiguous signal for neutrino oscillations independent of the details of the solar ... It is particularly important to see the effect of the core of the earth [19].

  14. Active-bridge oscillator

    Science.gov (United States)

    Wessendorf, Kurt O.

    2001-01-01

    An active bridge oscillator is formed from a differential amplifier where positive feedback is a function of the impedance of one of the gain elements and a relatively low value common emitter resistance. This use of the nonlinear transistor parameter h stabilizes the output and eliminates the need for ALC circuits common to other bridge oscillators.

  15. On the Dirac oscillator

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima

    2007-01-01

    In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra C 7. The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit. (author)

  16. Grazing Impact Oscillations

    NARCIS (Netherlands)

    Weger, J.G.; Water, van de W.; Molenaar, J.

    2000-01-01

    An impact oscillator is a periodically driven system that hits a wall when its amplitude exceeds a critical value. We study impact oscillations where collisions with the wall are with near-zero velocity (grazing impacts). A characteristic feature of grazing impact dynamics is a geometrically

  17. Semiannual report to Congress, October 1, 1995--March 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    This Office of Inspector General Semiannual Report to the Congress covers the period from October 1, 1995, through March 31, 1996. The report summarizes significant audit, inspection, and investigative accomplishments for the reporting period, a large portion of which facilitated Department of Energy management efforts to improve management controls and ensure efficient and effective operation of its programs. A major accomplishment during this period was the completion of financial statement audits for Fiscal Year 1995. Annual financial statement audits are mandated by the Chief Financial Officers Act of 1990. Narratives of our most significant reports are grouped by measures which the Office of Inspector General uses to gauge its performance. The common thread that ties the performance measures together is their emphasis on supporting Department efforts to produce high quality products at the lowest possible cost to the taxpayer. During this reporting period, the Office of Inspector General issued 67 audit and 15 inspection reports. For reports issued during the period, the Office of Inspector General made audit recommendations that, when implemented by management, could result in $134.6 million being put to better use. Management committed to taking corrective actions which the Office of Inspector General estimates will result in a more efficient use of funds totaling $333.2 million. Office of Inspector General investigations led to 6 criminal convictions and 1 pretrial diversion, as well as criminal and civil prosecutions which resulted in fines and recoveries of $10,942,714. The Office of Inspector General also provided 33 investigative referrals to management for recommended positive action.

  18. Low-rank coal research semiannual report, January 1992--June 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    This semiannual report is a compilation of seventeen reports on ongoing coal research at the University of North Dakota. The following research areas are covered: control technology and coal preparation; advanced research and technology development; combustion; liquefaction and gasification. Individual papers have been processed separately for inclusion in the Energy Science and Technology Database.

  19. Fusion materials semiannual progress report for period ending December 31, 1999

    International Nuclear Information System (INIS)

    Burn, G.

    2000-01-01

    This is the twenty-seventh in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components

  20. Fusion materials semiannual progress report for period ending December 31, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G.

    2000-03-01

    This is the twenty-seventh in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components.

  1. Unconventional gas recovery program. Semi-annual report for the period ending September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Manilla, R.D. (ed.)

    1980-04-01

    This document is the third semi-annual report describing the technical progress of the US DOE projects directed at gas recovery from unconventional sources. Currently the program includes Methane Recovery from Coalbeds Project, Eastern Gas Shales Project, Western Gas Sands Project, and Geopressured Aquifers Project.

  2. Fifth Semiannual Report of the Commission to the Congress: Atomic Energy Development, 1947- 1948

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, David E.; Bacher, Robert F.; Pike, Sumner T.; Strauss, Lewis L.

    1949-01-01

    The document represents the fifth semiannual report to Congress, covering specifically the various developments in atomic energy since the inception of the Atomic Energy Commission in 1946. This fifth report represents an expansion of effort in all phases of atomic energy development and is prepared against a background of world affairs.

  3. Eighth Semiannual Report of the Commission to the Congress, July 1950

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon; Murray, Thomas E.; Pike, Sumner T.; Smyth, H. D.

    1950-07-01

    The document represents the eighth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program. As has been done in several of the previous mid-year reports, this report includes detail on another major phase of the national atomic energy program: control of radiation hazards.

  4. Thirteenth Semiannual Report of the Commission to the Congress, January 1953

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1953-01-31

    The document represents the thirteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1952. Part two focuses on the annual financial report, while part three covers public safety in continental weapons tests.

  5. Eleventh Semiannual Report of the Commission to the Congress, January 1952

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1952-01-31

    The document represents the eleventh semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1951. Part II covers financial aspects and Part III, Applications in Plant Science.

  6. NRC regulatory agenda: Semiannual report, July--December 1996. Volume 15, Number 2

    International Nuclear Information System (INIS)

    1997-03-01

    The NRC Regulatory Agenda is a compilation of all rules on which the NRC has recently completed action, or has proposed action, or is considering action, and all petitions for rulemaking which have been received by the Commission and are pending disposition by the Commission. The Regulatory Agenda is updated and issued semiannually

  7. Modeling the impact and costs of semiannual mass drug administration for accelerated elimination of lymphatic filariasis.

    Directory of Open Access Journals (Sweden)

    Wilma A Stolk

    Full Text Available The Global Program to Eliminate Lymphatic Filariasis (LF has a target date of 2020. This program is progressing well in many countries. However, progress has been slow in some countries, and others have not yet started their mass drug administration (MDA programs. Acceleration is needed. We studied how increasing MDA frequency from once to twice per year would affect program duration and costs by using computer simulation modeling and cost projections. We used the LYMFASIM simulation model to estimate how many annual or semiannual MDA rounds would be required to eliminate LF for Indian and West African scenarios with varied pre-control endemicity and coverage levels. Results were used to estimate total program costs assuming a target population of 100,000 eligibles, a 3% discount rate, and not counting the costs of donated drugs. A sensitivity analysis was done to investigate the robustness of these results with varied assumptions for key parameters. Model predictions suggested that semiannual MDA will require the same number of MDA rounds to achieve LF elimination as annual MDA in most scenarios. Thus semiannual MDA programs should achieve this goal in half of the time required for annual programs. Due to efficiency gains, total program costs for semiannual MDA programs are projected to be lower than those for annual MDA programs in most scenarios. A sensitivity analysis showed that this conclusion is robust. Semiannual MDA is likely to shorten the time and lower the cost required for LF elimination in countries where it can be implemented. This strategy may improve prospects for global elimination of LF by the target year 2020.

  8. Ordering in nematic liquid crystals from NMR cross-polarization ...

    Indian Academy of Sciences (India)

    In this article the use of cross polarization for measuring dipolar couplings in liquid crystals is illustrated. Transient oscillations observed during cross polarization provide the dipolar couplings between essentially isolated nearest neighbour spins which can be extracted for several sites simultaneously by employing ...

  9. Eighteenth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, January - June 1955

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1955-07-30

    The document represents the eighteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1955.

  10. Twelfth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, January - June 1952

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1952-07-01

    The document represents the twelfth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1952.

  11. Fifteenth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, July - December 1953

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1954-01-31

    The document represents the fifteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1953.

  12. Fourteenth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, January - June 1953

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1953-07-31

    The document represents the fourteenth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1953.

  13. Harmonic oscillator Green's function

    International Nuclear Information System (INIS)

    Macek, J.H.; Ovchinnikov, S.Yu.; Khrebtukov, D.B.

    2000-01-01

    The Green's function for the harmonic oscillator in three dimensions plays an important role in the theory of atomic collisions. One representation of low-energy ion-atom collisions involves harmonic oscillator potentials. A closed-form expression for the harmonic oscillator Green's function, needed to exploit this representation, is derived. This expression is similar to the expression for the Coulomb Green's function obtained by Hostler and Pratt. Calculations of electron distributions for a model system of ion-atom collisions are reported to illustrate the theory.

  14. Oscillating foil propulsion

    OpenAIRE

    Hauge, Jacob

    2013-01-01

    Unsteady foil theory is discussed and applied on several cases of an oscillating foil. The oscillating foil is meant as a propulsion system for a platform supply vessel.Four case studies of foil oscillation have been performed. A thrust coefficient of 0.1 was achieved at an efficiency of 0.75. A thrust coefficient of minimum 0.184 is necessary to overcome the calm water resistance of the foil.Issues connected to coupled vessel-foil models are discussed.

  15. Neutrino Oscillation Physics

    CERN Document Server

    Kayser, Boris

    2014-04-10

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures.

  16. Oscillator, neutron modulator

    International Nuclear Information System (INIS)

    Agaisse, R.; Leguen, R.; Ombredane, D.

    1960-01-01

    The authors present a mechanical device and an electronic control circuit which have been designed to sinusoidally modulate the reactivity of the Proserpine atomic pile. The mechanical device comprises an oscillator and a mechanism assembly. The oscillator is made of cadmium blades which generate the reactivity oscillation. The mechanism assembly comprises a pulse generator for cycle splitting, a gearbox and an engine. The electronic device comprises or performs pulse detection, an on-off device, cycle pulse shaping, phase separation, a dephasing amplifier, electronic switches, counting scales, and control devices. All these elements are briefly presented

  17. Political polarization

    OpenAIRE

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  18. Political polarization.

    Science.gov (United States)

    Dixit, Avinash K; Weibull, Jörgen W

    2007-05-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  19. Oscillating fluid power generator

    Science.gov (United States)

    Morris, David C

    2014-02-25

    A system and method for harvesting the kinetic energy of a fluid flow for power generation with a vertically oriented, aerodynamic wing structure comprising one or more airfoil elements pivotably attached to a mast. When activated by the moving fluid stream, the wing structure oscillates back and forth, generating lift first in one direction then in the opposite direction. This oscillating movement is converted to unidirectional rotational movement in order to provide motive power to an electricity generator. Unlike other oscillating devices, this device is designed to harvest the maximum aerodynamic lift forces available for a given oscillation cycle. Because the system is not subjected to the same intense forces and stresses as turbine systems, it can be constructed less expensively, reducing the cost of electricity generation. The system can be grouped in more compact clusters, be less evident in the landscape, and present reduced risk to avian species.

  20. Fluctuations in LC Oscillators

    Directory of Open Access Journals (Sweden)

    O. Ondracek

    1994-03-01

    Full Text Available An analysis of the phase and amplitude fluctuations in oscillators with simple resonant circuit is presented. Negative feedback is used to minimize effect of the inherent noise produced by bipolar transistor on fluctuation characteristics.

  1. High frequency nanotube oscillator

    Science.gov (United States)

    Peng, Haibing [Houston, TX; Zettl, Alexander K [Kensington, TX

    2012-02-21

    A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.

  2. Again on neutrino oscillations

    International Nuclear Information System (INIS)

    Bilenky, S.M.; Pontecorvo, B.

    1976-01-01

    The general case is treated of a weak interaction theory in which a term violating lepton charges is present. In such a scheme the particles with definite masses are Majorana neutrinos (2N if in the weak interaction participate N four-component neutrinos). Neutrino oscillations are discussed and it is shown that the minimum average intensity at the earth of solar neutrinos is 1/2N of the intensity expected when oscillations are absent

  3. Neutrino oscillations with LSND

    International Nuclear Information System (INIS)

    Stancu, Ion

    2000-01-01

    The Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos Meson Physics Facility (LAMPF) has conducted searches for ν-bar μ → ν-bar e oscillations using ν-bar μ from μ + decay at rest (DAR) and for ν μ → ν e oscillations using ν μ from π + decay in flight (DIF). For the 1993-1995 data taking period, significant beam-excess events have been found in both oscillation channels. For the DAR search, a total excess of 51.8 +18.7 -16.9 ± 8.0 events from the ν-bar e p → e + n inverse β-decay reaction is observed, with e + energies between 20-60 MeV. For the DIF search, a total excess of 18.1 ± 6.6 ± 4.0 events from the ν e C → e - X inclusive reaction is observed, with e - energies between 60-200 MeV. If interpreted as neutrino oscillations, these excesses correspond to oscillation probabilities of (3.1±1.2±0.5) x 10 -3 and (2.6 ± 1.0 ± 0.5) x 10 -3 , respectively. Additional data collected during the 1996-1998 runs has been preliminarily analyzed for the DAR channel and yields very good agreement with the previously obtained results, for a combined oscillation probability of (3.3±0.9±0.5) x 10 -3

  4. Eigenpolarization theory of monolithic nonplanar ring oscillators

    Science.gov (United States)

    Nilsson, Alan C.; Gustafson, Eric K.; Byer, Robert L.

    1989-01-01

    Diode-laser-pumped monolithic nonplanar ring oscillators (NPROs) in an applied magnetic field can operate as unidirectional traveling-wave lasers. The diode laser pumping, monolithic construction, and unidirectional oscillation lead to narrow linewidth radiation. Here, a comprehensive theory of the eigenpolarizations of a monolithic NPRO is presented. It is shown how the properties of the integral optical diode that forces unidirectional operation depend on the choice of the gain medium, the applied magnetic field, the output coupler, and the geometry of the nonplanar ring light path. Using optical equivalence theorems to gain insight into the polarization characteristics of the NPRO, a strategy for designing NPROs with low thresholds and large loss nonreciprocities is given. An analysis of the eigenpolarizations for one such NPRO is presented, alternative optimization approaches are considered, and the prospects for further reducing the linewidths of these lasers are briefly discussed.

  5. Optical coating on a corrugated surface to align the polarization of an unpolarized wave without loss

    Science.gov (United States)

    Jen, Yi Jun

    2017-12-01

    A multilayer comprising birefringent thin films is devised to present to function as a polarization beam splitter and waveplate simultaneously. By arranging such a multilayer on a right triangle-shaped corrugated surface, a polarizer is realized to align the randomly oscillating electric field of an unpolarized wave into a linear polarized wave without loss.

  6. Spin torque and critical currents for magnetic vortex nano-oscillator in nanopillars

    Energy Technology Data Exchange (ETDEWEB)

    Guslienko, K Y; Gonzalez, J [Dpto. Fisica de Materiales, Universidad del Pais Vasco, 20018 Donostia-San Sebastian (Spain); Aranda, G R, E-mail: sckguslk@ehu.es [Centro de Fisica de Materiales UPV/EHU-CSIC, 20018 San Sebastian (Spain)

    2011-04-01

    We calculated the main dynamic parameters of the spin polarized current induced magnetic vortex oscillations in nanopillars, such as the range of current density, where vortex steady oscillations exist, the oscillation frequency and orbit radius. We accounted for both the non-linear vortex frequency and non-linear vortex damping. To describe the vortex excitations by the spin polarized current we used a generalized Thiele approach to motion of the vortex core as a collective coordinate. All the calculation results are represented via the free layer sizes, saturation magnetization, and the Gilbert damping. Predictions of the developed model can be checked experimentally.

  7. Office of Inspector General semiannual report to Congress, October 1, 1996--March 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This Office of Inspector General Semiannual Report to the Congress covers the period from October 1, 1996, through March 31, 1997. The report summarizes significant audit, inspection, and investigative accomplishments for the reporting period which facilitated Department of Energy management efforts to improve management controls and ensure efficient and effective operation of its programs. Narratives of the most significant reports are grouped by measures which the Office of Inspector General uses to gauge its performance. The common thread that ties the performance measures together is their emphasis on supporting Department efforts to produce high quality products at the lowest possible cost to the taxpayer. Five such performance measures were used during this semiannual period to present outcomes of Office of Inspector General work in terms of improvements in Department programs and operations.

  8. Environmental restoration/waste management-applied technology semiannual report, January--June 1992

    International Nuclear Information System (INIS)

    Adamson, M.; Kline-Simon, K.

    1992-01-01

    This is the first issue from the Lawrence Livermore National Laboratory of The Environmental Restoration/Waste Management-Applied Technology (ER/WM-AT) Semiannual Report, a continuation of the Advanced Processing Technology (APT) Semiannual Report. The name change reflects the consolidation of the APT Program with the Environmental Restoration and Waste Management Program to form the Environmental Restoration/Waste Management-Applied Technology (ER/WM-AT) Program. The Livermore site mirrors, on a small scale, many of the environmental and waste management problems of the DOE Complex. The six articles in this issue cover incineration- alternative technologies, process development for waste minimization, the proposed Mixed Waste Management Facility, dynamic underground stripping, electrical resistance tomography, and Raman spectroscopy for remote characterization of underground tanks

  9. Ecological Monitoring Program at the Waste Isolation Pilot Plant: Second semiannual report, January 1985--June 1985

    International Nuclear Information System (INIS)

    Fischer, N.T.

    1985-12-01

    This is the second semiannual report of the Ecological Monitoring Program (EMP) at the Waste Isolation Pilot Plant (WIPP) project in southeastern New Mexico. The purpose of the EMP is to quantify and assess the impacts of WIPP construction activities on the surrounding ecosystem. The predicted impacts include: (1) alteration of natural habitat, (2) deposition of salt and dust, and (3) increased human activity and noise. This report describes the data collection activities and presents results, analyses, and discussions for the period of January through June, 1985. Also included are data collected prior to this period which were not available for inclusion in the first EMP semiannual report and data collected after this period which provide a more complete basis for the analyses and discussion. The eight subprograms currently active in the EMP are: environmental photography, soil chemistry, soil microbiology, vegetation, wildlife, meteorology, air quality, and water quality. 16 refs., 37 figs., 17 tabs

  10. Nuclear fusion project. Semi-annual report of the Association KfK/EURATOM

    International Nuclear Information System (INIS)

    Kast, G.

    1987-05-01

    This semi-annual report gives 36 short descriptions of the work done in the framework of the Nuclear Fusion Project and outlines studies for NET/INTOR and for ECRH power sources at 150 GHz. Tables of fusion technology contracts, of NET contracts, of KfK departments contributing to the Fusion Project, and of the Fusion Project management staff complete this report. (GG)

  11. Fourth Semiannual Report to the Congress by the United States Atomic Energy Commission, July 1948

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, David E.; Bacher, Robert F.; Pike, Sumner T.; Strauss, Lewis L.; Waymack, William W.

    1948-07-01

    The document includes the letter of submittal and the Fourth semiannual report. These reports are called for pursuant to Section 17 of the Atomic Energy Act of 1946. This fourth report incorporates some changes to the report. In order to make these reports of maximum value to Members of Congress, the Commission has prepared this mid-year report as a specialized document giving a comprehensive account of several major phases of the atomic energy program.

  12. National Institute for Global Environmental Change. Semi-annual report, July 1, 1991--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Werth, G.C.

    1992-04-01

    This document is the Semi-Annual Report of the National Institute for Global Environmental Change for the reporting period July 1 to December 31, 1991. The report is in two parts. Part I presents the mission of the Institute, examples of progress toward that mission, a brief description of the revised management plan, and the financial report. Part II presents the statements of the Regional Center Directors along with progress reports of the projects written by the researchers themselves.

  13. Unconventional gas recovery program. Semi-annual report for the period ending March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Wise, R.L. (ed.)

    1979-08-01

    This document is the second semi-annual report describing the technical progress of the US DOE projects directed at gas recovery from unconventional sources. Currently the program includes: Methane Recovery from Coalbeds Project, Eastern Gas Shales Project, Western Gas Sand Project, and Geopressured Aquifers Project. This report is divided into five parts: a summary (Section 1), and a section devoted to each resource (Sections 2 through 5). Each resource section presents information which serves as an introduction to that project.

  14. Spatial Distribution and Semiannual Variation of Cold-Dense Plasma Sheet

    Science.gov (United States)

    Bai, Shichen; Shi, Quanqi; Tian, Anmin; Nowada, Motoharu; Degeling, Alexander W.; Zhou, Xu-Zhi; Zong, Qiu-Gang; Rae, I. Jonathan; Fu, Suiyan; Zhang, Hui; Pu, Zuyin; Fazakerly, Andrew N.

    2018-01-01

    The cold-dense plasma sheet (CDPS) plays an important role in the entry process of the solar wind plasma into the magnetosphere. Investigating the seasonal variation of CDPS occurrences will help us better understand the long-term variation of plasma exchange between the solar wind and magnetosphere, but any seasonal variation of CDPS occurrences has not yet been reported in the literature. In this paper, we investigate the seasonal variation of the occurrence rate of CDPS using Geotail data from 1996 to 2015 and find a semiannual variation of the CDPS occurrences. Given the higher probability of solar wind entry under stronger northward interplanetary magnetic field (IMF) conditions, 20 years of IMF data (1996-2015) are used to investigate the seasonal variation of IMF Bz under northward IMF conditions. We find a semiannual variation of IMF Bz, which is consistent with the Russell-McPherron (R-M) effect. We therefore suggest that the semiannual variation of CDPS may be related to the R-M effect.

  15. Oscillations in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Hoeye, Gudrun Kristine

    1999-07-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  16. An oscillating dynamic model of collective cells in a monolayer

    Science.gov (United States)

    Lin, Shao-Zhen; Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao

    2018-03-01

    Periodic oscillations of collective cells occur in the morphogenesis and organogenesis of various tissues and organs. In this paper, an oscillating cytodynamic model is presented by integrating the chemomechanical interplay between the RhoA effector signaling pathway and cell deformation. We show that both an isolated cell and a cell aggregate can undergo spontaneous oscillations as a result of Hopf bifurcation, upon which the system evolves into a limit cycle of chemomechanical oscillations. The dynamic characteristics are tailored by the mechanical properties of cells (e.g., elasticity, contractility, and intercellular tension) and the chemical reactions involved in the RhoA effector signaling pathway. External forces are found to modulate the oscillation intensity of collective cells in the monolayer and to polarize their oscillations along the direction of external tension. The proposed cytodynamic model can recapitulate the prominent features of cell oscillations observed in a variety of experiments, including both isolated cells (e.g., spreading mouse embryonic fibroblasts, migrating amoeboid cells, and suspending 3T3 fibroblasts) and multicellular systems (e.g., Drosophila embryogenesis and oogenesis).

  17. Oscillating Finite Sums

    KAUST Repository

    Alabdulmohsin, Ibrahim M.

    2018-03-07

    In this chapter, we use the theory of summability of divergent series, presented earlier in Chap. 4, to derive the analogs of the Euler-Maclaurin summation formula for oscillating sums. These formulas will, in turn, be used to perform many remarkable deeds with ease. For instance, they can be used to derive analytic expressions for summable divergent series, obtain asymptotic expressions of oscillating series, and even accelerate the convergence of series by several orders of magnitude. Moreover, we will prove the notable fact that, as far as the foundational rules of summability calculus are concerned, summable divergent series behave exactly as if they were convergent.

  18. Non-linear oscillations

    CERN Document Server

    Hagedorn, Peter

    1982-01-01

    Thoroughly revised and updated, the second edition of this concise text provides an engineer's view of non-linear oscillations, explaining the most important phenomena and solution methods. Non-linear descriptions are important because under certain conditions there occur large deviations from the behaviors predicted by linear differential equations. In some cases, completely new phenomena arise that are not possible in purely linear systems. The theory of non-linear oscillations thus has important applications in classical mechanics, electronics, communications, biology, and many other branches of science. In addition to many other changes, this edition has a new section on bifurcation theory, including Hopf's theorem.

  19. Friedel oscillations in graphene

    DEFF Research Database (Denmark)

    Lawlor, J. A.; Power, S. R.; Ferreira, M.S.

    2013-01-01

    Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent fashion that Friedel oscillations in graphene have a strong sublattice...... asymmetry. As a result, the presence of impurities and/or defects may impact the distinct graphene sublattices very differently. Furthermore, such an asymmetry can be used to explain the recent observations that nitrogen atoms and dimers are not randomly distributed in graphene but prefer to occupy one...

  20. Oscillators from nonlinear realizations

    Science.gov (United States)

    Kozyrev, N.; Krivonos, S.

    2018-02-01

    We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.

  1. Equatorial annual oscillation with QBO-driven 5-year modulation in NCEP data

    Directory of Open Access Journals (Sweden)

    H. G. Mayr

    2007-02-01

    Full Text Available An analysis is presented of the stratospheric zonal wind and temperature variations supplied by the National Center for Environmental Prediction (NCEP. The derived zonal-mean variations are employed. Stimulated by modeling studies, the data are separated into the hemispherically symmetric and anti-symmetric components, and spectral analysis is applied to study the 12-month annual oscillation (AO and the quasi-biennial oscillation (QBO. For data samples that cover as much as 40 years, the zonal wind results reveal a pronounced 5-year modulation of the symmetric AO in the lower stratosphere, which is confined to equatorial latitudes. This modulation is also seen in the temperature variations but extends to high latitudes, qualitatively consistent with published model results. A comparison between different time intervals of the data indicates that the signature of the 5-year oscillation is larger when the QBO of 30 months is more pronounced. Thus there is circumstantial evidence that this particular QBO period is involved in generating the oscillation as was shown in a modeling study (Mayr et al., 2000. In agreement with the model, the spectral analysis also reveals a weak anti-symmetric 5-year oscillation in the zonal wind data, which could interact with the strong anti-symmetric AO to produce the modulation of the symmetric AO. The 30-month QBO is well suited to be synchronized by, and phase-locked to, the equatorial semi-annual oscillation (SAO, and this may explain why this QBO periodicity and its 5-year spin-off are observed to persist for many cycles.

  2. Equatorial Oscillation and Planetary Wave Activity in Saturn's Stratosphere Through the Cassini Epoch

    Science.gov (United States)

    Guerlet, S.; Fouchet, T.; Spiga, A.; Flasar, F. M.; Fletcher, L. N.; Hesman, B. E.; Gorius, N.

    2018-01-01

    Thermal infrared spectra acquired by Cassini/Composite InfraRed Spectrometer (CIRS) in limb-viewing geometry in 2015 are used to derive 2-D latitude-pressure temperature and thermal wind maps. These maps are used to study the vertical structure and evolution of Saturn's equatorial oscillation (SEO), a dynamical phenomenon presenting similarities with the Earth's quasi-biennal oscillation (QBO) and semi-annual oscillation (SAO). We report that a new local wind maximum has appeared in 2015 in the upper stratosphere and derive the descent rates of other wind extrema through time. The phase of the oscillation observed in 2015, as compared to 2005 and 2010, remains consistent with a ˜15 year period. The SEO does not propagate downward at a regular rate but exhibits faster descent rate in the upper stratosphere, combined with a greater vertical wind shear, compared to the lower stratosphere. Within the framework of a QBO-type oscillation, we estimate the absorbed wave momentum flux in the stratosphere to be on the order of ˜7 × 10-6 N m-2. On Earth, interactions between vertically propagating waves (both planetary and mesoscale) and the mean zonal flow drive the QBO and SAO. To broaden our knowledge on waves potentially driving Saturn's equatorial oscillation, we searched for thermal signatures of planetary waves in the tropical stratosphere using CIRS nadir spectra. Temperature anomalies of amplitude 1-4 K and zonal wave numbers 1 to 9 are frequently observed, and an equatorial Rossby (n = 1) wave of zonal wave number 3 is tentatively identified in November 2009.

  3. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  4. Twenty-third Semiannual Report of the Commission to the Congress, January 1958. Progress in peaceful uses of atomic energy July - December 1957

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Lewis L.

    1958-01-31

    The document represents the twenty-third semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period July - December 1957. A special part one of this semiannual report is titled ''Progress in the Peaceful Uses of Atomic Energy - A 3-year Summary.

  5. HANFORD SITE AIR OPERATING PERMIT SEMIANNUAL REPORT FOR THE PERIOD 07/01/2004 THRU 12/31/2004

    International Nuclear Information System (INIS)

    GREEN, W.E.

    2005-01-01

    The Hanford Site Air Operating Permit (AOP), Number 00-05-006, became effective on July 2, 2001. One condition contained in the AOP, ''Standard Terms and Conditions'', Section 4.3.3, is the requirement to submit semiannual reports by March 15th and September 15th each year, which are certified for truth, accuracy, and completeness by a Responsible Official. This semiannual report contains information from July 1, 2004 through December 31, 2004. Copies of semiannual reports are transmitted to the Washington State Department of Ecology (Ecology). the Washington State Department of Health (WDOH), the Benton Clean Air Authority (BCAA), and the US Environmental Protection Agency (EPA), Region 10. For the applicable reporting period, AOP, ''Standard Terms and Conditions'', Section 4.3.3, as amended in August 2002 and December 2002, identifies the following. (1) Each semiannual report will provide a reference to deviation reports submitted to the regulatory agencies as required by Section 4.5. ''Permit Deviation Reporting''. (2) Each semiannual report will consist of reports of any required monitoring not submitted previously to the agencies or a reference to reports of required monitoring submitted during the reporting period. (3) Each semiannual report will contain a summary of any substantiated air emission complaint investigation(s) required in Table 1.2 of AOP, Attachment 1, and issued during the reporting period. (4) For all minor radioactive emission points (potential to emit <0.1 mrem to the maximally exposed individual) listed in AOP, Attachment 2. Tables 1.2. 1.3, and 2.1, each semiannual report will confirm that any required monitoring was conducted to verify low emissions during the reporting period. Data derived from that monitoring will be reported in the Annual National Emission Standards for Hazardous Air Pollutants (NESHAP) Report (AOP, ''Standard Terms and Conditions'', Section 4.3.1). AOP requirement is for annual monitoring (e.g., four 1 week samples

  6. Features of annual and semiannual variations derived from the global ionospheric maps of total electron content

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2008-01-01

    Full Text Available In the present work we use the NASA-JPL global ionospheric maps of total electron content (TEC, firstly to construct TEC maps (TEC vs. magnetic local time MLT, and magnetic latitude MLAT in the interval from 1999 to 2005. These TEC maps were, in turn, used to estimate the annual-to-mean amplitude ratio, A1, and the semiannual-to-mean amplitude ratio, A2, as well as the latitudinal symmetrical and asymmetrical parts, A' and A" of A1. Thus, we investigated in detail the TEC climatology from maps of these indices, with an emphasis on the quantitative presentation for local time and latitudinal changes in the seasonal, annual and semiannual anomalies of the ionospheric TEC. Then we took the TEC value at 14:00 LT to examine various anomalies at a global scale following the same procedure. Results reveal similar features appearing in NmF2, such as that the seasonal anomaly is more significant in the near-pole regions than in the far-pole regions and the reverse is true for the semiannual anomaly; the winter anomaly has least a chance to be observed at the South America and South Pacific areas. The most impressive feature is that the equinoctial asymmetry is most prominent at the East Asian and South Australian areas. Through the analysis of the TIMED GUVI columnar [O/N2] data, we have investigated to what extent the seasonal, annual and semiannual variations can be explained by their counterparts in [O/N2]. Results revealed that the [O/N2] variation is a major contributor to the daytime winter anomaly of TEC, and it also contributes to some of the semiannual and annual anomalies. The contribution to the anomalies unexplained by the [O/N2] data could possibly be due to the dynamics associated with thermospheric winds and electric fields.

  7. Modeling microtubule oscillations

    DEFF Research Database (Denmark)

    Jobs, E.; Wolf, D.E.; Flyvbjerg, H.

    1997-01-01

    Synchronization of molecular reactions in a macroscopic volume may cause the volume's physical properties to change dynamically and thus reveal much about the reactions. As an example, experimental time series for so-called microtubule oscillations are analyzed in terms of a minimal model for thi...

  8. Neutrino oscillation experiments

    International Nuclear Information System (INIS)

    Camilleri, L.

    1996-01-01

    Neutrino oscillation experiments (ν μ →ν e and ν μ →ν τ ) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs

  9. A simple violin oscillator

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    For acoustic tests the violin is driven laterally at the bridge by a small speaker of the type commonly found in pocket transistor radios. An audio oscillator excites the tone which is picked up by a sound level meter. Gross patterns of vibration modes are obtained by the Chladni method.

  10. The variational spiked oscillator

    International Nuclear Information System (INIS)

    Aguilera-Navarro, V.C.; Ullah, N.

    1992-08-01

    A variational analysis of the spiked harmonic oscillator Hamiltonian -d 2 / d x 2 + x 2 + δ/ x 5/2 , δ > 0, is reported in this work. A trial function satisfying Dirichlet boundary conditions is suggested. The results are excellent for a large range of values of the coupling parameter. (author)

  11. From excitability to oscillations

    DEFF Research Database (Denmark)

    Postnov, D. E.; Neganova, A. Y.; Jacobsen, J. C. B.

    2013-01-01

    One consequence of cell-to-cell communication is the appearance of synchronized behavior, where many cells cooperate to generate new dynamical patterns. We present a simple functional model of vasomotion based on the concept of a two-mode oscillator with dual interactions: via relatively slow...

  12. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...

  13. Neutrino oscillation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, L. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-11-01

    Neutrino oscillation experiments ({nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub {tau}}) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs.

  14. Nonlinearity in oscillating bridges

    Directory of Open Access Journals (Sweden)

    Filippo Gazzola

    2013-09-01

    Full Text Available We first recall several historical oscillating bridges that, in some cases, led to collapses. Some of them are quite recent and show that, nowadays, oscillations in suspension bridges are not yet well understood. Next, we survey some attempts to model bridges with differential equations. Although these equations arise from quite different scientific communities, they display some common features. One of them, which we believe to be incorrect, is the acceptance of the linear Hooke law in elasticity. This law should be used only in presence of small deviations from equilibrium, a situation which does not occur in widely oscillating bridges. Then we discuss a couple of recent models whose solutions exhibit self-excited oscillations, the phenomenon visible in real bridges. This suggests a different point of view in modeling equations and gives a strong hint how to modify the existing models in order to obtain a reliable theory. The purpose of this paper is precisely to highlight the necessity of revisiting the classical models, to introduce reliable models, and to indicate the steps we believe necessary to reach this target.

  15. Solar neutrino oscillations

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1993-01-01

    The special properties of solar neutrinos that render this flux so uniquely important in searches for neutrino masses and flavor mixing are reviewed. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained through analogies with more familiar atomic physics phenomena

  16. Charge oscillations in orbitrons

    International Nuclear Information System (INIS)

    Porto, M.; Gomes, L.C.

    1981-01-01

    A statistical model for the electron distribution in orbitrons is constructed where the effect of the end plates is considered. A comparison is made with the measured density of charge. The electromagnetic oscillations generated by orbitrons are calculated as pressure waves and the results obtained are compared with the data. (Author) [pt

  17. solar neutrino oscillation phenomenology

    Indian Academy of Sciences (India)

    sRUBABATI GOsWAMI. Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad 211 019, India. Email: sruba@mri.ernet.in. Abstract. This article summarises the status of the solar neutrino oscillation phe- nomenology at the end of 2002 in the light of the SNO and KamLAND results. We first present the allowed ...

  18. On a generalized oscillator: invariance algebra and interbasis expansions

    International Nuclear Information System (INIS)

    Hakopyan, E.M.; Pogosyan, G.S.; Sisakyan, A.N.; Kibler, M.

    1998-01-01

    This article deals with a quantum-mechanical system which generalizes the ordinary isotropic harmonic oscillator system. We give the coefficients connecting the polar and Cartesian bases for D=2 and the coefficients connecting the Cartesian and cylindrical bases as well as the cylindrical and spherical bases for D=3. These interbasis expansion coefficients are found to be analytic continuations to real values of their arguments of the Clebsch-Gordan coefficients for the group SU(2). For D=2, the super integrable character for the generalized oscillator system is investigated from the point of view of a quadratic invariance algebra

  19. Modeling Tides, Planetary Waves, and Equatorial Oscillations in the MLT

    Science.gov (United States)

    Mengel, J. G.; Mayr, H. G.; Drob, D. P.; Porter, H. S.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    Applying Hines Doppler Spread Parameterization for gravity waves (GW), our 3D model reproduces some essential features that characterize the observed seasonal variations of tides and planetary waves in the upper mesosphere. In 2D, our model also reproduces the large Semi-Annual Oscillation (SAO) and Quasi Biennial Oscillation (QBO) observed in this region at low latitudes. It is more challenging to describe these features combined in a more comprehensive self consistent model, and we give a progress report that outlines the difficulties and reports some success. In 3D, the GW's are partially absorbed by tides and planetary waves to amplify them. Thus the waves are less efficient in generating the QBO and SAO at equatorial latitudes. Some of this deficiency is compensated by the fact that the GW activity is observed to be enhanced at low latitudes. Increasing the GW source has the desired effect to boost the QBO, but the effect is confined primarily to the stratosphere. With increasing altitude, the meridional circulation becomes more important in redistributing the momentum deposited in the background flow by the GW's. Another factor involved is the altitude at which the GW's originate, which we had originally chosen to be the surface. Numerical experiments show that moving this source altitude to the top of the troposphere significantly increases the efficiency for generating the QBO without affecting much the tides and planetary waves in the model. Attention to the details in which the GW source comes into play thus appears to be of critical importance in modeling the phenomenology of the MLT. Among the suite of numerical experiments reported, we present a simulation that produced significant variations of tides and planetary waves in the upper mesosphere. The effect is related to the QBO generated in the model, and GW filtering is the likely cause.

  20. Bimodal oscillations in nephron autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A N; Mosekilde, E

    2002-01-01

    The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular ...

  1. Hanford Site Air Operating Permit Semiannual Report for the period July 21 2001 Thru December 31 2001

    International Nuclear Information System (INIS)

    GREEN, W.E.

    2002-01-01

    The Hanford Site Air Operating Permit (AOP), Number 00-05-006, became effective on July 2, 2001. One condition contained in the AOP, ''Standard Terms and Conditions'', Section 4.3.3, is the requirement to submit semiannual reports by March 15th and August 15th each year, which are certified for truth and accuracy by a Responsible Official. This first semiannual report contains information for the period from July 2, 2001 through December 31, 2001. Hereafter, the March 15th semiannual report will contain information for the period from July 1 through December 31. The semiannual report submitted by August 15th will contain information for the period from January 1 through June 30. Copies of the semiannual reports are transmitted to the Washington State Department of Ecology (Ecology), the Washington State Department of Health (WDOH), the Benton Clean Air Authority (BCAA), and the U.S. Environmental Protection Agency (EPA), Region 10. For the applicable reporting period, AOP, ''Standard Terms and Conditions'', Section 4.3.3, identifies the following: (1) Each semiannual report will provide a reference to deviation reports submitted to the regulatory agencies as required by Section 4.5, ''Permit Deviation Reporting''. (2) Each semiannual report will consist of reports of any required monitoring not submitted previously to the agencies or a reference to reports of required monitoring that were submitted during the reporting period. (3) Each semiannual report will contain a summary of any substantiated air emission complaint investigation(s) required in Table 1.2 of AOP, Attachment 1, and issued during the reporting period (4) For all minor radioactive emission points (potential to emit <0.1 mrem to the maximally exposed individual) listed in AOP, Attachment 2. Tables 1.2, 1.3 and 2.1. each semiannual report will confirm that any required monitoring was conducted to verify low emissions during the reporting period. The data derived from that monitoring will be reported

  2. Observation and analysis of oscillations in linear accelerators

    International Nuclear Information System (INIS)

    Seeman, J.T.

    1991-11-01

    This report discusses the following on oscillation in linear accelerators: Betatron Oscillations; Betatron Oscillations at High Currents; Transverse Profile Oscillations; Transverse Profile Oscillations at High Currents.; Oscillation and Profile Transient Jitter; and Feedback on Transverse Oscillations

  3. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  4. Nonlinear (Anharmonic Casimir Oscillator

    Directory of Open Access Journals (Sweden)

    Habibollah Razmi

    2011-01-01

    Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.

  5. Plasma oscillations in porous samples

    Directory of Open Access Journals (Sweden)

    Kornyushin Y.

    2004-01-01

    Full Text Available The influence of the shape of a sample on the type of uniform dipole collective electrons oscillations is discussed. In samples of a bulk shape uniform bulk dipole oscillations cannot exist. They exist in samples of a thin slab shape only. However in essentially porous materials the electrostatic energy of the oscillation in a sample is considerably larger thus leading to stronger restoring force and higher frequency of the oscillation. When this frequency exceeds the Langmuir frequency, the oscillation becomes of a bulk type. .

  6. Polare maskuliniteter

    Directory of Open Access Journals (Sweden)

    Marit Anne Hauan

    2012-05-01

    Full Text Available In this paper my aim is to read and understand the journal of Gerrit de Veer from the last journey of William Barents to the Arctic Regions in 1596 and the journal of captain Junge on his hunting trip from Tromsø to Svalbard in 1834.It is nearly 240 years between this to voyages. The first journal is known as the earliest report from the arctic era. Gerrit de Veer adds instructive copper engravings to his text and give us insight in the crews meeting with this new land. Captain Junges journal is found together with his dead crew in a house in a fjord nearby Ny-Ålesund and has no drawings, but word. Both of these journals may be read as sources of the knowledge and understanding of the polar region. They might also unveil the ideas of how to deal with and survive under the challenges that is given. In addition one can ask if the sources can tell us more about how men describe their challenges. Can the way they expressed themselves in the journals give us an understanding of masculinity? And not least help us to create good questions of the change in the ideas of masculinities which is said to follow the change in understanding of the wilderness.

  7. Neutrino Masses and Oscillations

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Treille, Daniel

    2002-01-01

    This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos.

  8. Oscillations in quasineutral plasmas

    International Nuclear Information System (INIS)

    Grenier, E.

    1996-01-01

    The purpose of this article is to describe the limit, as the vacuum electric permittivity goes to zero, of a plasma physics system, deduced from the Vlasov-Poisson system for special initial data (distribution functions which are analytic in the space variable, with compact support in velocity), a limit also called open-quotes quasineutral regimeclose quotes of the plasma, and the related oscillations of the electric field, with high frequency in time. 20 refs

  9. Oscillations with laboratory neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Saitta, Biagio

    2001-05-01

    The status of searches for oscillations using neutrinos produced in the laboratory is reviewed. The most recent results from experiments approaching completion are reported and the potential capabilities of long baseline projects being developed in USA and Europe are considered and compared. The steps that should naturally follow this new generation of experiments are outlined and the impact of future facilities - such as neutrino factories or conventional superbeams - in precision measurements of elements of the neutrino mixing matrix is discussed.

  10. A 20-day period standing oscillation in the northern winter stratosphere

    Directory of Open Access Journals (Sweden)

    K. Hocke

    2013-04-01

    Full Text Available Observations of the ozone profile by a ground-based microwave radiometer in Switzerland indicate a dominant 20-day oscillation in stratospheric ozone, possibly related to oscillations of the polar vortex edge during winter. For further understanding of the nature of the 20-day oscillation, the ozone data set of ERA Interim meteorological reanalysis is analyzed at the latitude belt of 47.5° N and in the time from 1979 to 2010. Spectral analysis of ozone time series at 7 hPa indicates that the 20-day oscillation is maximal at two locations: 7.5° E, 47.5° N and 60° E, 47.5° N. Composites of the stream function are derived for different phases of the 20-day oscillation of stratospheric ozone at 7 hPa in the Northern Hemisphere. The streamline at Ψ = −2 × 107 m2 s−1 is in the vicinity of the polar vortex edge. The other streamline at Ψ = 4 × 107 m2 s1 surrounds the Aleutian anticyclone and goes to the subtropics. The composites show 20-day period standing oscillations at the polar vortex edge and in the subtropics above Northern Africa, India, and China. The 20-day period standing oscillation above Aral Sea and India is correlated to the strength of the Aleutian anticyclone.

  11. Phase measurement for driven spin oscillations in a storage ring

    Science.gov (United States)

    Hempelmann, N.; Hejny, V.; Pretz, J.; Soltner, H.; Augustyniak, W.; Bagdasarian, Z.; Bai, M.; Barion, L.; Berz, M.; Chekmenev, S.; Ciullo, G.; Dymov, S.; Eversmann, D.; Gaisser, M.; Gebel, R.; Grigoryev, K.; Grzonka, D.; Guidoboni, G.; Heberling, D.; Hetzel, J.; Hinder, F.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Koop, I.; Kulikov, A.; Lehrach, A.; Lenisa, P.; Lomidze, N.; Lorentz, B.; Maanen, P.; Macharashvili, G.; Magiera, A.; Mchedlishvili, D.; Mey, S.; Müller, F.; Nass, A.; Nikolaev, N. N.; Nioradze, M.; Pesce, A.; Prasuhn, D.; Rathmann, F.; Rosenthal, M.; Saleev, A.; Schmidt, V.; Semertzidis, Y.; Senichev, Y.; Shmakova, V.; Silenko, A.; Slim, J.; Stahl, A.; Stassen, R.; Stephenson, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Tagliente, G.; Talman, R.; Thörngren Engblom, P.; Trinkel, F.; Uzikov, Yu.; Valdau, Yu.; Valetov, E.; Vassiliev, A.; Weidemann, C.; Wrońska, A.; Wüstner, P.; Zuprański, P.; Żurek, M.; JEDI Collaboration

    2018-04-01

    This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in Jülich using a vector polarized, bunched 0.97 GeV /c deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.

  12. Numerical Model of an Injection-Locked Wideband Frequency Modulator for Polar Transmitters

    NARCIS (Netherlands)

    Bashir, I.; Staszewski, R.B.; Balsara, P.T.

    2017-01-01

    We present a numerical model of a wideband injection-locked frequency modulator used in a polar transmitter for 3G cellular radio application. At the heart of the system is a self-injection-locked oscillator with a programmable linear tuning range of up to 200 MHz at 4-GHz oscillation frequency.

  13. Short- and mid-term oscillations of solar, geomagnetic activity and cosmic-ray intensity during the last two solar magnetic cycles

    Science.gov (United States)

    Singh, Y. P.; Badruddin

    2017-04-01

    Short-and mid-term oscillations of the solar activity (sunspot number and 10.7 cm solar flux), geomagnetic activity (Ap index) and cosmic-ray intensity (neutron monitor count rate) are analysed during the past two solar-magnetic cycles (1968-1989 and 1989-2014). We have implemented the wavelet analysis on the daily time resolution data of sunspot number (SSN), 10.7 cm solar flux, geomagnetic Ap index and Oulu neutron monitor count rate. Results suggest that few quasi and intermittent oscillations are observed with remarkable power density in addition to fundamental periods, like 27 day (synodic period), 154 day (Rieger period), semi-annual, annual, 1.3 year, and 1.7 year. We have consistently observed first (27 day), second (13.5 day) and third (9.0 day) solar-rotation harmonics in the geomagnetic Ap-index during both the magnetic cycles. Rieger period is more pronounced in SSN and solar flux during 1980-82 and 1990-92. Semi-annual variation of Ap-index is consistently observed during both the magnetic cycles. The annual and 1.85 year variation are also observed in all the considered parameters with good signatures in CRI.

  14. Fusion Materials Semiannual Progress Report for Period Ending December 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliff, A.F.; Burn, G.

    1999-04-01

    This is the twenty-fifth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the U.S. Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately.

  15. Fusion Materials Semiannual Progress Report for the Period Ending June 30, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F.

    1999-09-01

    This is the twenty-sixth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and its reported separately.

  16. Ninth Semiannual Report of the Commission to the Congress, July - December 1950. January 1951

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon; Glennan, T. Keith; Murray, Thomas E.; Pike, Sumner T.; Smyth, H. D.

    1951-01-31

    The document represents the ninth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program. This ninth report gives a summary of the year's program operations insofar as they can be reported within the limits of national security. It provides as well a brief review of the methods which the Commission follows in contracting with industries, research institutions, and with universities and colleges for the carrying on of the many phases of the national atomic energy program.

  17. Fusion materials semiannual progress report for the period ending June 30, 1998

    International Nuclear Information System (INIS)

    Burn, G.

    1998-09-01

    This is the twenty-fourth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database

  18. Semi-annual report on strategic special nuclear material inventory differences

    International Nuclear Information System (INIS)

    1981-01-01

    This report provides and explains the differences between the amounts of nuclear materials charged to DOE facilities and the amounts that could be physically inventoried. This report covers data for the period from October 1, 1979, through March 31, 1980, and includes accounting corrections for data from earlier periods. It is the seventh such semiannual report. These data and explanations, together with the absences of physical indications of any theft attempt, support a finding that during this period no theft or diversion of strategic spcial nuclear material has occurred

  19. Special Inspector General for Iraq Reconstruction: Quarterly Report and Semiannual Report to the United States Congress

    Science.gov (United States)

    2007-07-30

    administrative fees? Subsequently, in the January 30, 2007 Quar- terly Report and Semiannual Report, SIGIR further elaborated on the objectives to include...6/30/2007 372 W91GY0-06-F-0065-NA-0001 ATLANTIC DIVING SUPPLY, INC. *CM563A* PC: 130000, LI: ISIAF, CHOCOLATE CHIP FIELD JACKETS $2,002,755.00...1,226,463.00 $0.00 CEFMS ISFF1 6/30/2007 481 W91GY0-06-C-0036-NA-0001 IRAQI CONTRACTOR - 4285 *CM563A* PC: 130000, LI: ISIAF, CHOCOLATE CHIP FIELD JACKETS

  20. Special Inspector General for Iraq Reconstruction. Quarterly and Semiannual Report to the United States Congress

    Science.gov (United States)

    2007-07-30

    USAID’s administrative fees? Subsequently, in the January 30, 2007 Quar- terly Report and Semiannual Report, SIGIR further elaborated on the objectives...CEFMS ISFF1 6/30/2007 372 W91GY0-06-F-0065-NA-0001 ATLANTIC DIVING SUPPLY, INC. *CM563A* PC: 130000, LI: ISIAF, CHOCOLATE CHIP FIELD JACKETS...1,226,463.00 $1,226,463.00 $0.00 CEFMS ISFF1 6/30/2007 481 W91GY0-06-C-0036-NA-0001 IRAQI CONTRACTOR - 4285 *CM563A* PC: 130000, LI: ISIAF, CHOCOLATE CHIP

  1. National Council on Radiation Protection and Measurements semiannual technical progress report, March 1989--August 1989

    International Nuclear Information System (INIS)

    Ney, W.R.

    1991-01-01

    This semiannual technical progress report is for the period 1 March 1989 through 31 August 1989. This National Council on Radiation Protection and Measurements (NCRP) program is designed to provide recommendations for radiation protection based on scientific principles. During this period several reports were published covering the topics of occupational radiation exposure, medical exposure, radon control, dosimetry, and radiation protection standards. Accomplishments of various committees are also reported; including the committees on dental x-ray protection, radiation safety in uranium mining and milling, ALARA, instrumentation, records maintenance, occupational exposures of medical personnel, emergency planning, and others. (SM)

  2. Fusion reactor materials semiannual progress report for the period ending March 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This is the fourteenth in a series of semiannual technical progress reports on fusion reactor materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Depart of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Separate abstracts were prepared for each individual section.

  3. Fusion reactor materials semiannual progress report for the period ending March 31, 1993

    International Nuclear Information System (INIS)

    1993-07-01

    This is the fourteenth in a series of semiannual technical progress reports on fusion reactor materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Depart of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Separate abstracts were prepared for each individual section

  4. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... contralateral to stimulus side and additionally an unexpected 20 Hz activity was observed slightly lateralized in the frontal central region. The gamma phase locking may be a manifestation of early somatosensory feature integration. The analyses suggest that the high frequency activity consists of two distinct...

  5. Neutrino oscillations at LAMPF

    International Nuclear Information System (INIS)

    Carlini, R.; Choi, C.; Donohue, J.

    1985-01-01

    Work at Argonne continues on the construction of the neutrino oscillation experiment (E645). Construction of detector supports and active shield components were completed at the Provo plant of the principal contractor for the project (the Pittsburgh-Des Moines Corporation). Erection of the major experimental components was completed at the LAMPF experimental site in mid-March 1985. Work continues on the tunnel which will house the detector. Construction of detector components (scintillators and proportional drift tubes) is proceeding at Ohio State University and Louisiana State University. Consolidation of these components into the 20-ton neutrino detector is beginning at LAMPF

  6. Theory of oscillators

    CERN Document Server

    Andronov, Aleksandr Aleksandrovich; Vitt, Aleksandr Adolfovich

    1966-01-01

    Theory of Oscillators presents the applications and exposition of the qualitative theory of differential equations. This book discusses the idea of a discontinuous transition in a dynamic process. Organized into 11 chapters, this book begins with an overview of the simplest type of oscillatory system in which the motion is described by a linear differential equation. This text then examines the character of the motion of the representative point along the hyperbola. Other chapters consider examples of two basic types of non-linear non-conservative systems, namely, dissipative systems and self-

  7. Brain Oscillations, Hypnosis, and Hypnotizability

    Science.gov (United States)

    Jensen, Mark P.; Adachi, Tomonori; Hakimian, Shahin

    2014-01-01

    In this article, we summarize the state-of-science knowledge regarding the associations between hypnosis and brain oscillations. Brain oscillations represent the combined electrical activity of neuronal assemblies, and are usually measured as specific frequencies representing slower (delta, theta, alpha) and faster (beta, gamma) oscillations. Hypnosis has been most closely linked to power in the theta band and changes in gamma activity. These oscillations are thought to play a critical role in both the recording and recall of declarative memory and emotional limbic circuits. Here we propose that it is this role that may be the mechanistic link between theta (and perhaps gamma) oscillations and hypnosis; specifically that theta oscillations may facilitate, and that changes in gamma activity observed with hypnosis may underlie, some hypnotic responses. If these hypotheses are supported, they have important implications for both understanding the effects of hypnosis, and for enhancing response to hypnotic treatments. PMID:25792761

  8. Brain Oscillations, Hypnosis, and Hypnotizability.

    Science.gov (United States)

    Jensen, Mark P; Adachi, Tomonori; Hakimian, Shahin

    2015-01-01

    This article summarizes the state-of-science knowledge regarding the associations between hypnosis and brain oscillations. Brain oscillations represent the combined electrical activity of neuronal assemblies, usually measured as specific frequencies representing slower (delta, theta, alpha) and faster (beta, gamma) oscillations. Hypnosis has been most closely linked to power in the theta band and changes in gamma activity. These oscillations are thought to play a critical role in both the recording and recall of declarative memory and emotional limbic circuits. The authors propose that this role may be the mechanistic link between theta (and perhaps gamma) oscillations and hypnosis, specifically, that the increases in theta oscillations and changes in gamma activity observed with hypnosis may underlie some hypnotic responses. If these hypotheses are supported, they have important implications for both understanding the effects of hypnosis and for enhancing response to hypnotic treatments.

  9. Bounded-oscillation Pushdown Automata

    Directory of Open Access Journals (Sweden)

    Pierre Ganty

    2016-09-01

    Full Text Available We present an underapproximation for context-free languages by filtering out runs of the underlying pushdown automaton depending on how the stack height evolves over time. In particular, we assign to each run a number quantifying the oscillating behavior of the stack along the run. We study languages accepted by pushdown automata restricted to k-oscillating runs. We relate oscillation on pushdown automata with a counterpart restriction on context-free grammars. We also provide a way to filter all but the k-oscillating runs from a given PDA by annotating stack symbols with information about the oscillation. Finally, we study closure properties of the defined class of languages and the complexity of the k-emptiness problem asking, given a pushdown automaton P and k >= 0, whether P has a k-oscillating run. We show that, when k is not part of the input, the k-emptiness problem is NLOGSPACE-complete.

  10. Seventh Semiannual Report of the Commission to the Congress: Atomic Energy and the Physical Sciences, January 1950

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, David E.

    1950-01-01

    The document represents the seventh semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up briefly the major activities and developments in the national atomic energy program in Part I. Part II focuses on research in the physical sciences and progress in atomic energy.

  11. Cumulative Index to the First Fifteen Semiannual Reports of the Commission to the Congress. January 1947 - 1953

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1954-01-31

    The first fifteen semiannual reports of the United States Atomic Energy Commission to Congress cover the major unclassified activities of the Commission from January 1947 through December 1953. This cumulative name and subject index provides a guide to the information published in these reports.

  12. Data Summary Report for the Semiannual Tritium Survey for Fourmile Branch and the F- and H-Area Seeplines

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J. II [Westinghouse Savannah River Company, AIKEN, SC (United States) Exploration Resources

    1996-12-16

    This report presents a summary of the definitive data validation and verification for the Semiannual Tritium Survey for Fourmile Branch and the F- and H-Area Seeplines. The survey was performed at the request of the WSRC ERD and conducted by WSRC/ESS. This report was prepared under the direction of EPD/EMS.

  13. Data Summary Report for the 1998 Semiannual Tritium Surveys for Fourmile Branch and the F- and H-Area Seeplines

    International Nuclear Information System (INIS)

    Koch, J.

    1999-01-01

    This report presents a summary of the definitive data validation and verification for the 1998 semiannual tritium surveys for Fourmile Branch and the F- and H-Area Seeplines. The project was performed under the direction of WSRC EAS/Ecology. This report was prepared under the direction of EPD/EMS

  14. 40 CFR 62.15355 - What must I include in the semiannual out-of-compliance reports?

    Science.gov (United States)

    2010-07-01

    ..., and your corrective actions: (1) Concentration or percent reduction of sulfur dioxide emissions. (2...) Concentration of carbon monoxide emissions. (4) Load level of your municipal waste combustion unit. (5... 40 Protection of Environment 8 2010-07-01 2010-07-01 false What must I include in the semiannual...

  15. U.S. Department of Education, Office of Inspector General Semiannual Report to Congress, April 1, 1997-September 30, 1997.

    Science.gov (United States)

    Office of Inspector General (ED), Washington, DC.

    This semiannual report to Congress summarizes the activities of the Department of Education's Office of Inspector General (OIG) for the 6-month period ending September 30, 1997. The OIG gave Congressional testimony regarding the modernization of student-financial-assistance-information programs, the Loan Consolidation process, the Federal Direct…

  16. Data Summary Report for the 1997 Semiannual Tritium Survey for Fourmile Branch and the F- and H-Area Seeplines

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J.W. II

    1998-01-05

    This report presents a summary of the definitive data validation and verification for the 1997 RFI/RI semiannual tritium survey for Fourmile Branch and the F- and H-Area Seeplines. The RFI/RI was performed under the direction of WSRC ESS/Ecology. This report was prepared under the direction EPD/EMS.

  17. An Artificial Muscle Ring Oscillator

    OpenAIRE

    O’Brien, Benjamin Marc; Anderson, Iain Alexander

    2012-01-01

    Dielectric elastomer artificialmuscles have great potential for the creation of novel pumps, motors, and circuitry. Control of these devices requires an oscillator, either as a driver or clock circuit, which is typically provided as part of bulky, rigid, and costly external electronics. Oscillator circuits based on piezo-resistive dielectric elastomer switch technology provide a way to embed oscillatory behavior into artificial muscle devices. Previous oscillator circuits were not digital, ab...

  18. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  19. The Preboreal oscillation around the Nordic Seas: terrestrial and lacustrine responses

    DEFF Research Database (Denmark)

    Börck, Svante; Rundgren, Mats; Ingolfsson, Olafur

    1997-01-01

    The occurrence of an early Preboreal climatic cooling/oscillation (PBO) in lacustrine and glacial records from northwest Europe, Iceland and Greenland is reviewed and documented. The often subtle response of the proxy records to this oscillation, in combination with its short duration, make it di...... is implied by a simultaneous and distinct rise in the atmospheric 14C/12C ratio. A slow-down of the thermohaline circulation may temporarily have pushed the Polar Front further south...

  20. Nanoscale relaxation oscillator

    Science.gov (United States)

    Zettl, Alexander K.; Regan, Brian C.; Aloni, Shaul

    2009-04-07

    A nanoscale oscillation device is disclosed, wherein two nanoscale droplets are altered in size by mass transport, then contact each other and merge through surface tension. The device may also comprise a channel having an actuator responsive to mechanical oscillation caused by expansion and contraction of the droplets. It further has a structure for delivering atoms between droplets, wherein the droplets are nanoparticles. Provided are a first particle and a second particle on the channel member, both being made of a chargeable material, the second particle contacting the actuator portion; and electrodes connected to the channel member for delivering a potential gradient across the channel and traversing the first and second particles. The particles are spaced apart a specified distance so that atoms from one particle are delivered to the other particle by mass transport in response to the potential (e.g. voltage potential) and the first and second particles are liquid and touch at a predetermined point of growth, thereby causing merging of the second particle into the first particle by surface tension forces and reverse movement of the actuator. In a preferred embodiment, the channel comprises a carbon nanotube and the droplets comprise metal nanoparticles, e.g. indium, which is readily made liquid.

  1. Unstable oscillators based hyperchaotic circuit

    DEFF Research Database (Denmark)

    Murali, K.; Tamasevicius, A.; G. Mykolaitis, A.

    1999-01-01

    A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations in the circ......A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations...

  2. Spatial computation with gamma oscillations

    Science.gov (United States)

    Engelhard, Ben; Vaadia, Eilon

    2014-01-01

    Gamma oscillations in cortex have been extensively studied with relation to behavior in both humans and animal models; however, their computational role in the processing of behaviorally relevant signals is still not clear. One oft-overlooked characteristic of gamma oscillations is their spatial distribution over the cortical space and the computational consequences of such an organization. Here, we advance the proposal that the spatial organization of gamma oscillations is of major importance for their function. The interaction of specific spatial distributions of oscillations with the functional topography of cortex enables select amplification of neuronal signals, which supports perceptual and cognitive processing. PMID:25249950

  3. The Duffing oscillator with damping

    DEFF Research Database (Denmark)

    Johannessen, Kim

    2015-01-01

    An analytical solution to the differential equation describing the Duffing oscillator with damping is presented. The damping term of the differential equation and the initial conditions satisfy an algebraic equation, and thus the solution is specific for this type of damping. The nonlinear term....... It is established that the period of oscillation is shorter compared to that of a linearized model but increasing with time and asymptotically approaching the period of oscillation of the linear damped model. An explicit expression for the period of oscillation has been derived, and it is found to be very accurate....

  4. Linearly polarized intracavity passive Q-switched Yb-doped ...

    Indian Academy of Sciences (India)

    2014-02-14

    Feb 14, 2014 ... Q-switched fibre lasers with high peak power have attracted a lot of attention due to many applications in the fields of industrial processing and medical treatments. For special applications of nonlinear frequency shifting like frequency doubling and optical paramet- ric oscillation, linearly polarized ...

  5. Non-perturbative calculation of equilibrium polarization of stored electron beams

    International Nuclear Information System (INIS)

    Yokoya, Kaoru.

    1992-05-01

    Stored electron/positron beams polarize spontaneously owing to the spin-flip synchrotron radiation. In the existing computer codes, the degree of the equilibrium polarization has been calculated using perturbation expansions in terms of the orbital oscillation amplitudes. In this paper a new numerical method is presented which does not employ the perturbation expansion. (author)

  6. Photoinduced High-Frequency Charge Oscillations in Dimerized Systems

    Science.gov (United States)

    Yonemitsu, Kenji

    2018-04-01

    Photoinduced charge dynamics in dimerized systems is studied on the basis of the exact diagonalization method and the time-dependent Schrödinger equation for a one-dimensional spinless-fermion model at half filling and a two-dimensional model for κ-(bis[ethylenedithio]tetrathiafulvalene)2X [κ-(BEDT-TTF)2X] at three-quarter filling. After the application of a one-cycle pulse of a specifically polarized electric field, the charge densities at half of the sites of the system oscillate in the same phase and those at the other half oscillate in the opposite phase. For weak fields, the Fourier transform of the time profile of the charge density at any site after photoexcitation has peaks for finite-sized systems that correspond to those of the steady-state optical conductivity spectrum. For strong fields, these peaks are suppressed and a new peak appears on the high-energy side, that is, the charge densities mainly oscillate with a single frequency, although the oscillation is eventually damped. In the two-dimensional case without intersite repulsion and in the one-dimensional case, this frequency corresponds to charge-transfer processes by which all the bonds connecting the two classes of sites are exploited. Thus, this oscillation behaves as an electronic breathing mode. The relevance of the new peak to a recently found reflectivity peak in κ-(BEDT-TTF)2X after photoexcitation is discussed.

  7. The development of coal-based technologies for Department of Defense facilities. Volume 2, Appendices. Semiannual technical progress report, September 28, 1994--March 27, 1995

    International Nuclear Information System (INIS)

    Miller, B.G.; Bartley, D.A.; Hatcher, P.

    1996-01-01

    This semiannual progress report contains the following appendices: description of the 1,000 lb steam/h watertube research boiler; the Pennsylvania CGE model; Phase II, subtask 3.9 coal market analysis; the CGE model; and sector definition

  8. The development of coal-based technologies for Department of Defense facilities. Volume 2, Appendices. Semiannual technical progress report, September 28, 1994--March 27, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Miller, B.G.; Bartley, D.A.; Hatcher, P. [Pennsylvania State Univ., University Park, PA (United States). Energy and Fuels Research Center] [and others

    1996-10-15

    This semiannual progress report contains the following appendices: description of the 1,000 lb steam/h watertube research boiler; the Pennsylvania CGE model; Phase II, subtask 3.9 coal market analysis; the CGE model; and sector definition.

  9. On the variability of the seasonal scale oscillations over Cachoeira Paulista (22.7°S, 45°W), Brazil

    Science.gov (United States)

    Guharay, Amitava; Batista, Paulo Prado; Clemesha, Barclay Robert

    2014-12-01

    The characteristics of long period atmospheric oscillations are studied using long-term meteor radar wind observations over a low-latitude Brazilian station, Cachoeira Paulista (22.7°S, 45°W). The semiannual oscillation (SAO) amplitude decreases gradually with altitude in the mesopause region, while the annual oscillation (AO) amplitude exhibits a minimum at mid-mesopause with significant interannual variability. The quasi-biennial oscillation (QBO) obtained by removing the SAO and AO from the zonal wind exhibits an out-of-phase relationship at lower mesopause heights (approximately 81 km) and mid-stratosphere (approximately 10 hPa). There is an evident signature of modulation of the mesospheric SAO (MSAO) and mesospheric AO (MAO) by the QBO. The diurnal tide is surmised to contribute significantly to drive the easterly phase of these oscillations, especially MSAO and MAO through depositing westward momentum to the background wind. The westerly phase of the MSAO is believed to support the growth of the quasi-2-day wave (QTDW) by wave filtering. The QTDW is found to be strong during the easterly phase of the MAO indicating a possible existence of the barotropic/baroclinic instability during summer and a possible role of the QTDW towards westward forcing of the background wind.

  10. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  11. Twenty-fifth Semiannual Report of the Commission to the Congress, January 1959. Atomic Industrial Process and Second World Conference, July - December 1958

    Energy Technology Data Exchange (ETDEWEB)

    McCone, John A.

    1959-01-31

    The document represents the twenty-fifth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program in Part Three, covering the period July - December 1958. A special Part One of this semiannual report is titled ''Industrial Atomic Progress During 1958", and a Part Two entitled "Second World Conference on Peaceful Uses of Atomic Energy".

  12. Hyperchaos in coupled Colpitts oscillators

    DEFF Research Database (Denmark)

    Cenys, Antanas; Tamasevicius, Arunas; Baziliauskas, Antanas

    2003-01-01

    The paper suggests a simple solution of building a hyperchaotic oscillator. Two chaotic Colpitts oscillators, either identical or non-identical ones are coupled by means of two linear resistors R-k. The hyperchaotic output signal v(t) is a linear combination, specifically the mean of the individual...

  13. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    ... are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.

  14. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  15. Mechanical Parametric Oscillations and Waves

    Science.gov (United States)

    Dittrich, William; Minkin, Leonid; Shapovalov, Alexander S.

    2013-01-01

    Usually parametric oscillations are not the topic of general physics courses. Probably it is because the mathematical theory of this phenomenon is relatively complicated, and until quite recently laboratory experiments for students were difficult to implement. However parametric oscillations are good illustrations of the laws of physics and can be…

  16. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  17. Oscillator strengths for neutral technetium

    International Nuclear Information System (INIS)

    Garstang, R.H.

    1981-01-01

    Oscillator strengths have been calculated for most of the spectral lines of TcI which are of interest in the study of stars of spectral type S. Oscillator strengths have been computed for the corresponding transitions in MnI as a partial check of the technetium calculations

  18. Quasi Periodic Oscillations in Blazars

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy; Volume 35; Issue 3. Quasi Periodic Oscillations in Blazars ... Here we report our recent discoveries of Quasi-Periodic Oscillations (QPOs) in blazars time series data in X-ray and optical electromagnetic bands. Any such detection can give important ...

  19. Oscillating nonlinear acoustic shock waves

    DEFF Research Database (Denmark)

    Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

    2016-01-01

    We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... that at resonance a stationary state arise consisting of multiple oscillating shock waves. Off resonance driving leads to a nearly linear oscillating ground state but superimposed by bursts of a fast oscillating shock wave. Based on a travelling wave ansatz for the fluid velocity potential with an added 2'nd order...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

  20. Oscillating universe with quintom matter

    International Nuclear Information System (INIS)

    Xiong Huahui; Cai Yifu; Qiu Taotao; Piao Yunsong; Zhang Xinmin

    2008-01-01

    In this Letter, we study the possibility of building a model of the oscillating universe with quintom matter in the framework of 4-dimensional Friedmann-Robertson-Walker background. Taking the two-scalar-field quintom model as an example, we find in the model parameter space there are five different types of solutions which correspond to: (I) a cyclic universe with the minimal and maximal values of the scale factor remaining the same in every cycle, (II) an oscillating universe with its minimal and maximal values of the scale factor increasing cycle by cycle, (III) an oscillating universe with its scale factor always increasing, (IV) an oscillating universe with its minimal and maximal values of the scale factor decreasing cycle by cycle, and (V) an oscillating universe with its scale factor always decreasing

  1. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live......In this paper we estimate the degree, composition and development of geographical income polarization based on data at the individual and municipal level in Denmark from 1984 to 2002. Rising income polarization is reconfirmed when applying new polarization measures, the driving force being greater...

  2. Optical phonon features of triclinic montebrasite : dispersion analysis and non-polar Raman modes.

    OpenAIRE

    Almeida, Rafael M.; Höfer, Sonja; Mayerhöfer, Thomas G.; Popp, Jürgen; Krambrock, Klaus; Lobo, Ricardo P. S. M.; Dias, Anderson; Moreira, Roberto Luiz

    2015-01-01

    Polarized infrared and Raman spectra of triclinic LiAl(PO4)(OH) [montebrasite] single crystal were recorded for appropriate optical configurations. Dispersion analysis was applied on the infrared reflectivity spectra taken at low incidence angle (11 ) to determine the oscillator parameters and the dipole directions of the polar phonons. In particular, all the 27 polar phonons, predicted by group theory for triclinic P1 structure,were determined. The obtained dielectric tensor para...

  3. Oscillations of atomic nuclei in crystals

    OpenAIRE

    Vdovenkov, V. A.

    2002-01-01

    Oscillations of atomic nuclei in crystals are considered in this paper. It is shown that elastic nuclei oscillations relatively electron envelops (inherent, I-oscillations) and waves of such oscillations can exist in crystals at adiabatic condition. The types and energy quantums of I-oscillations for different atoms are determined. In this connection the adiabatic crystal model is offered. Each atom in the adiabatic model is submitted as I-oscillator whose stationary oscillatory terms are sho...

  4. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  5. Heat transfer with oscillating pressure and oscillating flow

    Science.gov (United States)

    Kornhauser, Alan A.; Smith, Joseph L., Jr.

    Heat exchangers in Stirling engines and many other reciprocating machines operating under conditions of both oscillating pressure and oscillating flow are discussed. Experiments were done on an apparatus consisting of a piston-cylinder space connected to an annular dead-end heat exchanger space. Instantaneous heat flux and center gas temperature were measured at six locations along the heat exchanger. The results were used to test the model, with the complex Nusselt number correlated against oscillating-flow Peclet number. The experimental results showed that the complex Nusselt number was capable of predicting the heat flux, but that there was at least one other important independent variable besides oscillating-flow Peclet number. Dimensional analysis suggested that this was either the ratio of gas thermal properties to those of the wall or a measure of compressibility effects.

  6. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  7. Fusion materials semiannual progress report for period ending June 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    This is the twenty-second in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Topics covered here are: vanadium alloys; silicon carbide composites; ferritic/martensitic steels; austenitic stainless steels; insulating ceramics and optical materials; solid breeding materials; radiation effects mechanistic studies and experimental methods; dosimetry damage parameters; activation calculations; materials engineering and design requirements; irradiation facilities; test matrices; and experimental methods.

  8. Office of Inspector General semiannual report to Congress, April 1--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    This Office of Inspector General Semiannual Report to the Congress covers the period from April 1 through September 30, 1995. The report summarizes significant audit, inspection, and investigative accomplishments for the reporting period, a large portion of which facilitated Department of Energy management efforts to improve management controls and ensure efficient and effective operation of its programs. Narratives of the most significant reports are grouped by six primary performance measures which the Office of Inspector General uses to gauge its attainment of the outcomes established in the Office of Inspector General Strategic Plan. The common thread that ties the performance measures together is their emphasis on supporting Department efforts to produce high quality products at the lowest possible cost to the taxpayer. The six performance measures present outcomes of Office of Inspector General work in terms of improvements in Department programs and operations.

  9. Annual and semiannual variations in the ionospheric F2-layer: II. Physical discussion

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    Full Text Available The companion paper by Zou et al. shows that the annual and semiannual variations in the peak F2-layer electron density (NmF2 at midlatitudes can be reproduced by a coupled thermosphere-ionosphere computational model (CTIP, without recourse to external influences such as the solar wind, or waves and tides originating in the lower atmosphere. The present work discusses the physics in greater detail. It shows that noon NmF2 is closely related to the ambient atomic/molecular concentration ratio, and suggests that the variations of NmF2 with geographic and magnetic longitude are largely due to the geometry of the auroral ovals. It also concludes that electric fields play no important part in the dynamics of the midlatitude thermosphere. Our modelling leads to the following picture of the global three-dimensional thermospheric circulation which, as envisaged by Duncan, is the key to explaining the F2-layer variations. At solstice, the almost continuous solar input at high summer latitudes drives a prevailing summer-to-winter wind, with upwelling at low latitudes and throughout most of the summer hemisphere, and a zone of downwelling in the winter hemisphere, just equatorward of the auroral oval. These motions affect thermospheric composition more than do the alternating day/night (up-and-down motions at equinox. As a result, the thermosphere as a whole is more molecular at solstice than at equinox. Taken in conjunction with the well-known relation of F2-layer electron density to the atomic/molecular ratio in the neutral air, this explains the F2-layer semiannual effect in NmF2 that prevails at low and middle latitudes. At higher midlatitudes, the seasonal behaviour depends on the geographic latitude of the winter downwelling zone, though the effect of the composition changes is modified by the large solar zenith angle at midwinter. The zenith angle effect is especially important in longitudes far from the magnetic

  10. Semi-annual report of the Department of Energy, Office of Environmental Management, Quality Assessment Program

    International Nuclear Information System (INIS)

    Greenlaw, P.D.

    1998-01-01

    This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are compiled with EML's results and are reported back to the participating contractors 30 days later. A summary of the reported results is available to the participants 4 days after the reporting deadline via the Internet at www.eml.doe.gov. This report presents the results from the analysis of the 47th set of environmental quality assessment samples (QAP XLVII) that were received on or before December 1, 1997

  11. NRC regulatory agenda: Semiannual report, January--June 1997. Volume 16, Number 1

    International Nuclear Information System (INIS)

    1997-08-01

    The Regulatory Agenda is a semiannual compilation of all rules on which the NRC has recently completed action, or has proposed action, or is considering action, and of all petitions for rulemaking that the NRC has received that are pending disposition. The agenda consists of two sections that have been updated through June 30, 1997. Section 1, ''Rules,'' includes (A) rules on which final action has been taken since December 31, 1996, the closing date of the last NRC Regulatory Agenda; (B) rules published previously as proposed rules on which the Commission has not taken final action; (C) rules published as advance notices of proposed rulemaking for which neither a proposed nor final rule has been issued; and (D) unpublished rules on which the NRC expects to take action. Section 2, ''Petitions for Rulemaking,'' includes (A) petitions denied or incorporated into final rules since December 31, 1996; (B) petitions incorporated into proposed rules; and (C) petitions pending staff review

  12. Annual and semiannual variations in the ionospheric F2-layer: II. Physical discussion

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    2000-08-01

    Full Text Available The companion paper by Zou et al. shows that the annual and semiannual variations in the peak F2-layer electron density (NmF2 at midlatitudes can be reproduced by a coupled thermosphere-ionosphere computational model (CTIP, without recourse to external influences such as the solar wind, or waves and tides originating in the lower atmosphere. The present work discusses the physics in greater detail. It shows that noon NmF2 is closely related to the ambient atomic/molecular concentration ratio, and suggests that the variations of NmF2 with geographic and magnetic longitude are largely due to the geometry of the auroral ovals. It also concludes that electric fields play no important part in the dynamics of the midlatitude thermosphere. Our modelling leads to the following picture of the global three-dimensional thermospheric circulation which, as envisaged by Duncan, is the key to explaining the F2-layer variations. At solstice, the almost continuous solar input at high summer latitudes drives a prevailing summer-to-winter wind, with upwelling at low latitudes and throughout most of the summer hemisphere, and a zone of downwelling in the winter hemisphere, just equatorward of the auroral oval. These motions affect thermospheric composition more than do the alternating day/night (up-and-down motions at equinox. As a result, the thermosphere as a whole is more molecular at solstice than at equinox. Taken in conjunction with the well-known relation of F2-layer electron density to the atomic/molecular ratio in the neutral air, this explains the F2-layer semiannual effect in NmF2 that prevails at low and middle latitudes. At higher midlatitudes, the seasonal behaviour depends on the geographic latitude of the winter downwelling zone, though the effect of the composition changes is modified by the large solar zenith angle at midwinter. The zenith angle effect is especially important in longitudes far from the magnetic poles. Here, the downwelling occurs

  13. Semi-annual report of the Department of Energy, Office of Environmental Management, Quality Assessment Program

    International Nuclear Information System (INIS)

    Greenlaw, P.D.; Minick, S.K.

    1998-01-01

    This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are compiled with EML's results and are reported back to the participating contractors 30 days later. This report presents the results from the analysis of the 48th set of environmental quality assessment samples (QAP XLVIII) that were received on or before June 1, 1998

  14. Semi-annual report on strategic special nuclear material inventory differences

    International Nuclear Information System (INIS)

    1984-07-01

    This fourteenth periodic semiannual report of Inventory Differences (ID) covers the last six months of fiscal year 1983 (April 1, 1983 through September 30, 1983), for the Department of Energy (DOE) and DOE contractor facilities possessing significant quantities of strategic special nuclear material (SSNM). Inventory Differences are expected in nuclear material processing and are not, in and of themselves, evidence of lost or stolen material. On the other hand, ID analysis provides valuable information on the effectiveness of the safeguards system's physical protection and material control measures as well as a check on the process controls and material management procedures. ID's outside safeguards control limits or involving a missing SSNM discrete item are investigated. If necessary, an operation may be shut down until an ID is resolved

  15. Fusion reactor materials. Semiannual progress report for period ending September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F.; Burn, G.L.; Knee`, S.S.; Dowker, C.L. [comps.

    1994-02-01

    This is the fifteenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; Special purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the U.S. Department of Energy. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  16. Automated solar cell assembly teamed process research. Semiannual subcontract report, December 6, 1993--June 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Nowlan, M. [Spire Corp., Bedford, MA (United States)

    1995-01-01

    This is the second Semiannual Technical Progress Report for the program titled `Automated Solar Cell Assembly Teamed Process Research` funded under National Renewable Energy Laboratory (NREL) subcontract No. ZAG-3-11219-01. This report describes the work done on Phase II of the program in the period from December 6, 1993 to June 30, 1994. Spire`s objective in this program is to develop high throughput (5 MW/yr) automated processes for interconnecting thin (200 {mu}m) silicon solar cells. High yield will be achieved with these fragile cells through the development of low mechanical stress and low thermal stress processes. For example, a machine vision system is being developed for cell alignment without mechanically contacting the cell edges, while a new soldering process is being developed to solder metal interconnect ribbons simultaneously to a cells` front and back contacts, eliminating one of the two heating steps normally used for soldering each cell.

  17. Semi-annual report of the Department of Energy, Office of Environmental Management, Quality Assessment Program

    Energy Technology Data Exchange (ETDEWEB)

    Greenlaw, P.D.

    1998-01-01

    This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are compiled with EML`s results and are reported back to the participating contractors 30 days later. A summary of the reported results is available to the participants 4 days after the reporting deadline via the Internet at www.eml.doe.gov. This report presents the results from the analysis of the 47th set of environmental quality assessment samples (QAP XLVII) that were received on or before December 1, 1997.

  18. Semi-annual report of the Department of Energy, Office of Environmental Management, Quality Assessment Program

    Energy Technology Data Exchange (ETDEWEB)

    Greenlaw, P.D.; Minick, S.K.

    1998-07-01

    This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are compiled with EML`s results and are reported back to the participating contractors 30 days later. This report presents the results from the analysis of the 48th set of environmental quality assessment samples (QAP XLVIII) that were received on or before June 1, 1998.

  19. Semi-annual report on strategic special nuclear material inventory differences

    International Nuclear Information System (INIS)

    1981-08-01

    This eighth periodic semiannual report of inventory differences covers the second six months of fiscal year 1980 (April 1, 1980, through September 30, 1980), for the Department of Energy (DOE) and DOE contractor facilities possessing significant quantities of strategic special nuclear material. Strategic special nuclear material is plutonium or uranium-233 or uranium-235 in material whose uranium-235 content is 20 percent or greater (known as highly enriched uranium). A significant quantity is either 2 kilograms of plutonium or uranium-233 or 5 kilograms of uranium-235 in highly enriched uranium or the appropriate weighted combination. All Inventory Differences reported here have been analyzed, investigated when necessary, and resolved. These data and explanations, together with the absences of physical indications of any theft attempt, support a finding that during this period no theft or diversion of strategic special nuclear material has occurred

  20. Office of Inspector General semiannual report to Congress, October 1, 1997--March 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    This Office of Inspector General (OIG) Semiannual Report to the Congress covers the period from October 1, 1997, through March 31, 1998. The report summarizes significant audit, inspection, and investigative accomplishments for the reporting period that facilitated Department of Energy (Department) efforts to improve management controls and ensure efficient and effective operation of its programs. This report highlights OIG accomplishments in support of its Strategic Plan. Narratives of the Office`s most significant reports are grouped by the strategic goals against which the OIG measures its performance. To put the OIG accomplishments for this reporting period in context, the following statistical information is provided: audit and inspection reports issued -- 47; recommendations that funds be put to better use -- $356,257,856; management commitment to taking corrective actions -- $289,106,445; criminal indictments/convictions -- 8; fines and recoveries -- $1,612,932; and investigative reports to management recommending positive change -- 21.

  1. Neutrino oscillation: status and outlooks

    International Nuclear Information System (INIS)

    Nedelec, P.

    1994-01-01

    Whether the neutrinos are massive or not is one of the most puzzling question of physics today. If they are massive, they can contribute significantly to the Dark Matter of the Universe. An other consequence of a non-zero mass of neutrinos is that they might oscillate from one flavor to another. This oscillation process is by now the only way to detect a neutrino with a mass in the few eV range. Several neutrino experiments are currently looking for such an oscillation, in different modes, using different techniques. An overview of the experimental situation for neutrino experiments at accelerators is given. (author). 9 refs., 5 figs., 5 tabs

  2. Collective oscillations in a plasma

    CERN Document Server

    Akhiezer, A I; Polovin, R V; ter Haar, D

    2013-01-01

    International Series of Monographs in Natural Philosophy: Collective Oscillations in a Plasma, Volume 7 presents specific topics within the general field of radio waves propagation. This book contains five chapters that address the theory of linear oscillations in a plasma, the spectra of the eigen oscillations, and the mechanism of high-frequency heating. The opening chapters deal with the self-consistent fields; development of initial perturbation; dispersion permittivity tensor of a plasma in a magnetic field; effect of thermal motion of particles on low-frequency resonances; excitation of

  3. Oscillations in Mathematical Biology

    CERN Document Server

    1983-01-01

    The papers in this volume are based on talks given at a one day conference held on the campus of Adelphi University in April 1982. The conference was organized with the title "Oscillations in Mathematical Biology;" however the speakers were allowed considerable latitutde in their choice of topics. In the event, the talks all concerned the dynamics of non-linear systems arising in biology so that the conference achieved a good measure of cohesion. Some of the speakers cho~e not to submit a manuscript for these proceedings, feeling that their material was too conjectural to be committed to print. Also the paper of Rinzel and Troy is a distillation of the two separate talks that the authors gave. Otherwise the material reproduces the conference proceedings. The conference was made possible by the generous support of the Office of the Dean of the College of Arts and Sciences at Adelphi. The bulk of the organization of the conference was carried out by Dr. Ronald Grisell whose energy was in large measure responsib...

  4. Principal oscillation patterns

    International Nuclear Information System (INIS)

    Storch, H. von; Buerger, G.; Storch, J.S. von

    1993-01-01

    The Principal Oscillation Pattern (POP) analysis is a technique which is used to simultaneously infer the characteristic patterns and time scales of a vector time series. The POPs may be seen as the normal modes of a linearized system whose system matrix is estimated from data. The concept of POP analysis is reviewed. Examples are used to illustrate the potential of the POP technique. The best defined POPs of tropospheric day-to-day variability coincide with the most unstable modes derived from linearized theory. POPs can be derived even from a space-time subset of data. POPs are successful in identifying two independent modes with similar time scales in the same data set. The POP method can also produce forecasts which may potentially be used as a reference for other forecast models. The conventional POP analysis technique has been generalized in various ways. In the cyclostationary POP analysis, the estimated system matrix is allowed to vary deterministically with an externally forced cycle. In the complex POP analysis not only the state of the system but also its ''momentum'' is modeled. Associated correlation patterns are a useful tool to describe the appearance of a signal previously identified by a POP analysis in other parameters. (orig.)

  5. Rabi oscillation between states of a coupled harmonic oscillator

    International Nuclear Information System (INIS)

    Park, Tae Jun

    2003-01-01

    Rabi oscillation between bound states of a single potential is well known. However the corresponding formula between the states of two different potentials has not been obtained yet. In this work, we derive Rabi formula between the states of a coupled harmonic oscillator which may be used as a simple model for the electron transfer. The expression is similar to typical Rabi formula for a single potential. This result may be used to describe transitions between coupled diabatic potential curves

  6. Global Status of Neutrino Oscillation

    Indian Academy of Sciences (India)

    monojit

    2014-11-08

    Outline of talk. Neutrino Oscillations: the context. Solar and geo neutrino physics. Reactor neutrino physics. Atmospheric and long-baseline neutrino physics. Atmospheric neutrinos and INO. Nov 8, 2014, IASc Annual Meeting, IIT-Madras, Chennai – p. 2 ...

  7. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  8. Environmental restoration/waste management-applied technology semiannual report, January--June 1992. Volume 1, No. 1

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, M.; Kline-Simon, K. [eds.

    1992-12-31

    This is the first issue from the Lawrence Livermore National Laboratory of The Environmental Restoration/Waste Management-Applied Technology (ER/WM-AT) Semiannual Report, a continuation of the Advanced Processing Technology (APT) Semiannual Report. The name change reflects the consolidation of the APT Program with the Environmental Restoration and Waste Management Program to form the Environmental Restoration/Waste Management-Applied Technology (ER/WM-AT) Program. The Livermore site mirrors, on a small scale, many of the environmental and waste management problems of the DOE Complex. The six articles in this issue cover incineration- alternative technologies, process development for waste minimization, the proposed Mixed Waste Management Facility, dynamic underground stripping, electrical resistance tomography, and Raman spectroscopy for remote characterization of underground tanks.

  9. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  10. Modelling solar-like oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Eggenberger, P; Miglio, A [Institut d' Astrophysique et de Geophysique de l' Universite de Liege, 17 Allee du 6 Aout, B-4000 Liege (Belgium); Carrier, F [Institute of Astronomy, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Mathis, S [CEA/DSM/DAPNIA/Service d' Astrophysique, CEA/Saclay, AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII, UMR 7158, 91191 Gif-sur-Yvette Cedex (France)], E-mail: eggenberger@Qastro.ulg.ac.be

    2008-10-15

    The computation of models of stars for which solar-like oscillations have been observed is discussed. After a brief intoduction on the observations of solar-like oscillations, the modelling of isolated stars and of stars belonging to a binary system is presented with specific examples of recent theoretical calibrations. Finally the input physics introduced in stellar evolution codes for the computation of solar-type stars is discussed with a peculiar emphasis on the modelling of rotation for these stars.

  11. The Torsional Oscillation and the Timing of the Solar Cycle: Is it Maximum Yet?

    DEFF Research Database (Denmark)

    Howe, R.; Christensen-Dalsgaard, J.; Hill, F.

    2013-01-01

    After the late start to Cycle 24 there are some indications that activity may have peaked as early as late 2011 and that the polar-field reversal has already occurred in the North. We use helioseismic measurements of the migrating zonal flow pattern known as the torsional oscillation to estimate ...

  12. Causes of the mid-latitudinal daytime NmF2 semi-annual anomaly at solar minimum

    Science.gov (United States)

    Pavlov, A. V.

    2018-04-01

    Ionospheric ionosonde and radar observations and theoretical calculations of the F2-layer peak altitude, hmF2, and number density, NmF2, over Millstone Hill during winter, spring, summer, and autumn geomagnetically quiet time periods at low solar activity are used to study the causes of the observed daytime NmF2 semi-annual anomaly. It follows from the model simulations that this anomalous phenomenon arises in the ionosphere mainly as a result of seasonal variations of the following atmospheric parameters: (1) the plasma drift along geomagnetic field lines due to corresponding changes in neutral wind components, (2) temperature and number densities of the neutral atmosphere, and (3) an optical thickness of the atmosphere caused by the dependence of the solar zenith angle on the day of the year for the same solar local time. Seasonal variations of the production rate unexcited O+ ions due to chemical reactions involving electronically excited O+ ions contribute to the formation of the NmF2 semi-annual anomaly during the predominant part of the existence time of this anomalous phenomenon. However, these seasonal variations are not significant, and this mechanism should be considered only as an additional source of the NmF2 semi-annual anomaly during its time of existence. The reactions of unexcited O+ ions with vibrationally excited N2 and O2 cause only weak changes of NmF2 and these changes are close in magnitude at a given solar local time during the winter, spring, summer, and autumn daytime conditions under consideration. Ignoring these reactions cannot produce a significant impact on the formation of the NmF2 semi-annual anomaly.

  13. Modeling nonlinearities in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

    2013-08-01

    We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

  14. Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film.

    Science.gov (United States)

    Capua, Amir; Rettner, Charles; Yang, See-Hun; Phung, Timothy; Parkin, Stuart S P

    2017-06-28

    Rabi oscillations describe the process whereby electromagnetic radiation interacts coherently with spin states in a non-equilibrium interaction. To date, Rabi oscillations have not been studied in one of the most common spin ensembles in nature: spins in ferromagnets. Here, using a combination of femtosecond laser pulses and microwave excitations, we report the classical analogue of Rabi oscillations in ensemble-averaged spins of a ferromagnet. The microwave stimuli are shown to extend the coherence-time resulting in resonant spin amplification. The results we present in a dense magnetic system are qualitatively similar to those reported previously in semiconductors which have five orders of magnitude fewer spins and which require resonant optical excitations to spin-polarize the ensemble. Our study is a step towards connecting concepts used in quantum processing with spin-transport effects in ferromagnets. For example, coherent control may become possible without the complications of driving an electromagnetic field but rather by using spin-polarized currents.

  15. Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film

    Science.gov (United States)

    Capua, Amir; Rettner, Charles; Yang, See-Hun; Phung, Timothy; Parkin, Stuart S. P.

    2017-06-01

    Rabi oscillations describe the process whereby electromagnetic radiation interacts coherently with spin states in a non-equilibrium interaction. To date, Rabi oscillations have not been studied in one of the most common spin ensembles in nature: spins in ferromagnets. Here, using a combination of femtosecond laser pulses and microwave excitations, we report the classical analogue of Rabi oscillations in ensemble-averaged spins of a ferromagnet. The microwave stimuli are shown to extend the coherence-time resulting in resonant spin amplification. The results we present in a dense magnetic system are qualitatively similar to those reported previously in semiconductors which have five orders of magnitude fewer spins and which require resonant optical excitations to spin-polarize the ensemble. Our study is a step towards connecting concepts used in quantum processing with spin-transport effects in ferromagnets. For example, coherent control may become possible without the complications of driving an electromagnetic field but rather by using spin-polarized currents.

  16. Magnetically Coupled Magnet-Spring Oscillators

    Science.gov (United States)

    Donoso, G.; Ladera, C. L.; Martin, P.

    2010-01-01

    A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of…

  17. On the nonlinear modeling of ring oscillators

    KAUST Repository

    Elwakil, Ahmed S.

    2009-06-01

    We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

  18. On the mechanism of oscillations in neutrophils

    DEFF Research Database (Denmark)

    Brasen, Jens Christian; Barington, Torben; Olsen, Lars Folke

    2010-01-01

    We have investigated the regulation of the oscillatory generation of H(2)O(2) and oscillations in shape and size in neutrophils in suspension. The oscillations are independent of cell density and hence do not represent a collective phenomena. Furthermore, the oscillations are independent...... of the external glucose concentration and the oscillations in H(2)O(2) production are 180 degrees out of phase with the oscillations in NAD(P)H. Cytochalasin B blocked the oscillations in shape and size whereas it increased the period of the oscillations in H(2)O(2) production. 1- and 2-butanol also blocked...... the oscillations in shape and size, but only 1-butanol inhibited the oscillations in H(2)O(2) production. We conjecture that the oscillations are likely to be due to feedback regulations in the signal transduction cascade involving phosphoinositide 3-kinases (PI3K). We have tested this using a simple mathematical...

  19. Discomfort caused by low-frequency lateral oscillation, roll oscillation and roll-compensated lateral oscillation.

    Science.gov (United States)

    Beard, George F; Griffin, Michael J

    2013-01-01

    Roll compensation during cornering (aligning the feet-to-head axis of the body with the resultant force) reduces lateral acceleration, but how any improvement in comfort depends on the frequency of the acceleration has not previously been investigated. Seated subjects judged the discomfort caused by lateral oscillation, roll oscillation and fully roll-compensated lateral oscillation at each of seven frequencies (0.25-1.0 Hz). Irrespective of whether it was caused by pure lateral acceleration or gravitational acceleration due to pure roll, acceleration in the plane of the seat caused similar discomfort at frequencies less than 0.4 Hz. From 0.4 to 1.0 Hz, with the same lateral acceleration in the plane of the seat, there was greater discomfort from roll oscillation than from lateral acceleration. With fully roll-compensated lateral oscillation, discomfort was less than with either the lateral component or the roll component of the motion from 0.2 to 0.5 Hz, but discomfort increased with increasing frequency and caused similar discomfort to pure roll oscillation at 1.0 Hz. Tilting can reduce passenger exposure to vehicle lateral acceleration when cornering, but how comfort depends on the frequency of motion was unknown. This study shows 'tilt-compensation' only improves comfort at frequencies less than 0.5 Hz. The findings affect tilting vehicles and the prediction of discomfort caused by low-frequency motions.

  20. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  1. Polarization in Sagittarius A*

    OpenAIRE

    Bower, Geoffrey C.

    2000-01-01

    We summarize the current state of polarization observations of Sagittarius A*, the compact radio source and supermassive black hole candidate in the Galactic Center. These observations are providing new tools for understanding accretion disks, jets and their environments. Linear polarization observations have shown that Sgr A* is unpolarized at frequencies as high as 86 GHz. However, recent single-dish observations indicate that Sgr A* may have strong linear polarization at frequencies higher...

  2. Designing magnetic droplet soliton nucleation employing spin polarizer

    Science.gov (United States)

    Mohseni, Morteza; Mohseni, Majid

    2018-04-01

    We show by means of micromagnetic simulations that spin polarizer in nano-contact (NC) spin torque oscillators as the representative of the fixed layer in an orthogonal pseudo-spin valve can be employed to design and to control magnetic droplet soliton nucleation and dynamics. We found that using a tilted spin polarizer layer decreases the droplet nucleation time which is more suitable for high speed applications. However, a tilted spin polarizer increases the nucleation current and decreases the frequency stability of the droplet. Additionally, by driving the magnetization inhomogenously at the NC region, it is found that a tilted spin polarizer reduces the precession angle of the droplet and through an interplay with the Oersted field of the DC current, it breaks the spatial symmetry of the droplet profile. Our findings explore fundamental insight into nano-scale magnetic droplet soliton dynamics with potential tunability parameters for future microwave electronics.

  3. A model of quasi-free scattering with polarized protons

    International Nuclear Information System (INIS)

    Teodoro, M.R.

    1976-01-01

    A quantitative evaluation, based on a simple model for spin-free coplanar and asymmetric reaction in 16 O, for 215 MeV incoming polarized protons confirms the use of the strong effective polarization of the knocked-out proton by the spin-orbit coupling and of the strong dependence of free, medium energy, proton-proton cross section on the relative orientation of the proton spins. Effective polarizations, momentum distributions and correlation cross sections have been calculated for the 1p sub(1/2), 1 p sub(3/2) and 1s sub(1/2) states in 16 O, using protons totally polarized orthogonal to the scattering plane. Harmonic oscillator and square wells have been used to generate the bound state wave functions, whereas the optical potentials have been taken spin-independent and purely imaginary [pt

  4. Electromagnetic properties of neutrinos: three new phenomena in neutrino spin oscillations

    Directory of Open Access Journals (Sweden)

    Studenikin Alexander

    2016-01-01

    Full Text Available In studies of neutrino electromagnetic properties we discuss three very inter-esting aspects related to neutrino spin oscillations. First we consider neutrino mixing and oscillations in the mass and flavour bases under the influence of a constant magnetic field with nonzero transversal and longitudinal components. Then we discuss the effect of neutrino spin oscillations induced by electroweak interactions of neutrino with moving matter in case there is matter transversal current or polarization. In the final part of the paper we discuss recently developed approach to description of neutrino spin and spin-flavour oscillations in a constant magnetic field that is based on the use of the exact neutrino stationary states in the magnetic field.

  5. Analysis of synchronized regimes for injection-locked spin-transfer nano-oscillators

    Energy Technology Data Exchange (ETDEWEB)

    D' Aquino, M., E-mail: daquino@uniparthenope.it [Department of Technology, University of Napoli ' Parthenope' , 80143 Napoli (Italy); Serpico, C. [Department of Engineering, University of Napoli Federico II, 80125 Napoli (Italy); Bonin, R. [Politecnico di Torino - Sede di Verres, 11029 Verres (Aosta) (Italy); Bertotti, G. [Istituto Nazionale di Ricerca Metrologica, 10135 Torino (Italy); Mayergoyz, I.D. [ECE Dept. and UMIACS, University of Maryland, College Park, MD 20742 (United States)

    2012-05-01

    The large-angle magnetization dynamics of an injection-locked spin-transfer nano-oscillator (STNO) is studied. The magnetic system is subject to the action of time-varying spin-polarized currents and external magnetic fields. The uniform mode theory is developed and describes the hysteretic synchronization mechanism in terms of bifurcations of equilibria and limit cycles of appropriate dynamical systems. Analytical predictions of control parameters for the synchronization between the magnetization self-oscillation and the external microwave excitations (current, field) are provided. The effect of temperature on the locking band and the hysteretic character of the oscillation response is analyzed. An analytical approach is developed to determine the thermally induced sidebands in the power spectral density of phase-locked oscillations as a function of control parameters. The analytical predictions are in good agreement with the results of numerical simulations.

  6. Vacuum oscillations around a large-Z ''nucleus''

    International Nuclear Information System (INIS)

    Kumano, S.; Iwazaki, A.

    1989-01-01

    We investigate a possible explanation of sharp e + peaks in heavy-ion collisions by analyzing QED with a large atomic number external source. We show that a highly polarized vacuum around a large Z ''nucleus'' has at least two neutral oscillation modes, whose energies are calculated to be 1.8 MeV and 1.5 MeV with an appropriate choice of the nuclear radius. They decay into a pair of e/sup +-/ through electromagnetic interactions. 8 refs., 1 fig

  7. ALG-2 oscillates in subcellular localization, unitemporally with calcium oscillations

    DEFF Research Database (Denmark)

    la Cour, Jonas Marstrand; Mollerup, Jens; Berchtold, Martin Werner

    2007-01-01

    A variety of stimuli can trigger intracellular calcium oscillations. Relatively little is known about the molecular mechanisms decoding these events. We show that ALG-2, a Ca2+-binding protein originally isolated as a protein associated with apoptosis, is directly linked to Ca2+ signalling. We...... localization in an oscillatory fashion unitemporally with Ca2+ oscillations, whereas a Ca2+-binding deficient mutant of ALG-2 did not redistribute. Using tagged ALG-2 as bait we identified its novel target protein Sec31A and based on the partial colocalization of endogenous ALG-2 and Sec31A we propose that ALG...

  8. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  9. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  10. Circular Motion of a Small Oscillator in a Zero-Point Field Without External Forces: Is It Possible?

    OpenAIRE

    Levin, Yefim S.

    2016-01-01

    A small dipole oscillator moving along a circular trajectory in zero-point electromagnetic field ( ZPF ) and with a polarization normal to the rotation plane, is considered. Temporal periodicity conditions are imposed on ZPF, associated with the way the rotating oscillator observes ZPF. They are similar to spatial boundary conditions in Casimir phenomenon and therefore result in ZPF spectrum change from continuous one to a discrete one and, as a consequence, an effective temperature of the mo...

  11. Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

    KAUST Repository

    Zhang, Qian

    2015-05-27

    We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom.

  12. Polarity Checks in Sectors 23 & 78

    CERN Document Server

    Calaga, R; Lamont, M; Ponce, L; Sun, Y; Tomás, R; Venturini-Delsolaro, W; Zimmermann, F

    2009-01-01

    During the first three LHC synchronization tests on August 10, August 24, and September 7, 2008, linear and higher-order polarity checks were performed with beam 1 in Sector 23 and beam 2 in Sector 78. The main principle of these checks was to launch free betatron oscillations and use the difference trajectory measurements with respect to inverted polarities of circuits under investigation. In the case of zero nominal strength for a circuit, a finite value was introduced. The magnet circuits subjected to these tests were the QT and QTL trim quadrupoles, the MQS skew quadrupoles, the SF and SD arc sextupole circuits, the MCS b3 spool pieces, the OD and OF Landau octupoles, and the MSS skew sextupoles. For some of these circuits sensitivity was enhanced by introducing large momentum offsets. To detect and remove improve spurious contributions from initially off-center orbits, four sets of trajectories were recorded, namely with and without oscillation, and with two magnet strength settings, respectively. We rep...

  13. Perturbations of gyrosynchrotron emission polarization from solar flares by sausage modes: forward modeling

    Science.gov (United States)

    Reznikova, V. E.; Van Doorsselaere, T.; Kuznetsov, A. A.

    2015-03-01

    We examined the polarization of the microwave flaring emission and its modulation by the fast sausage standing wave using a linear 3D magnetohydrodynamic model of a plasma cylinder. We analyzed the effects of the line-of-sight angle on the perturbations of the gyrosynchrotron intensity for two models: a base model with strong Razin suppression and a low-density model in which the Razin effect was negligible. The circular polarization (Stokes V) oscillation is in phase with the intensity oscillation, and the polarization degree (Stokes V/I) oscillates in phase with the magnetic field at the examined frequencies in both models. The two quantities experience a periodical reversal of their signs with a period equal to half of the sausage wave period when seen at a 90° viewing angle, in this case, their modulation depth reaches 100%.

  14. Real oscillations of virtual neutrinos

    International Nuclear Information System (INIS)

    Grimus, W.; Stockinger, P.

    1996-01-01

    We study the conditions for neutrino oscillations in a field-theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates x searrow P and x searrow D , respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual lines connecting production with detection in the total Feynman graph and all neutrino fields or states to be found in the discussion are mass eigenfields or eigenstates. We perform a thorough examination of the integral over the spatial components of the inner neutrino momentum and show that in the asymptotic limit L=|x searrow D -x searrow P |→∞ the virtual neutrinos become open-quote open-quote real close-quote close-quote and under certain conditions the usual picture of neutrino oscillations emerges without ambiguities. copyright 1996 The American Physical Society

  15. Damping of coupled harmonic oscillators

    Science.gov (United States)

    Dolfo, Gilles; Vigué, Jacques

    2018-03-01

    When two harmonic oscillators are coupled in the presence of damping, their dynamics exhibit two very different regimes depending on the relative magnitude of the coupling and damping terms At resonance, when the coupling has its largest effect, if the coupling dominates the damping, there is a periodic exchange of energy between the two oscillators while, in the opposite case, the energy transfer from one oscillator to the other one is irreversible. We prove that the border between these two regimes goes through an exceptional point and we briefly explain what is an exceptional point. The present paper is written for undergraduate students, with some knowledge in classical mechanics, but it may also be of interest for graduate students.

  16. Prediction of pilot induced oscillations

    Directory of Open Access Journals (Sweden)

    Valentin PANĂ

    2011-03-01

    Full Text Available An important problem in the design of flight-control systems for aircraft under pilotedcontrol is the determination of handling qualities and pilot-induced oscillations (PIO tendencieswhen significant nonlinearities exist in the vehicle description. The paper presents a method to detectpossible pilot-induced oscillations of Category II (with rate and position limiting, a phenomenonusually due to a misadaptation between the pilot and the aircraft response during some tasks in whichtight closed loop control of the aircraft is required from the pilot. For the analysis of Pilot in the LoopOscillations an approach, based on robust stability analysis of a system subject to uncertainparameters, is proposed. In this analysis the nonlinear elements are substituted by linear uncertainparameters. This approach assumes that PIO are characterized by a limit cycle behavior.

  17. Robust techniques for polarization and detection of nuclear spin ensembles

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Müller, Samuel; Chen, Qiong; Dhand, Ish; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2017-11-01

    Highly sensitive nuclear spin detection is crucial in many scientific areas including nuclear magnetic resonance spectroscopy, magnetic resonance imaging (MRI), and quantum computing. The tiny thermal nuclear spin polarization represents a major obstacle towards this goal which may be overcome by dynamic nuclear spin polarization (DNP) methods. The latter often rely on the transfer of the thermally polarized electron spins to nearby nuclear spins, which is limited by the Boltzmann distribution of the former. Here we utilize microwave dressed states to transfer the high (>92 % ) nonequilibrium electron spin polarization of a single nitrogen-vacancy center (NV) induced by short laser pulses to the surrounding 13C carbon nuclear spins. The NV is repeatedly repolarized optically, thus providing an effectively infinite polarization reservoir. A saturation of the polarization of the nearby nuclear spins is achieved, which is confirmed by the decay of the polarization transfer signal and shows an excellent agreement with theoretical simulations. Hereby we introduce the polarization readout by polarization inversion method as a quantitative magnetization measure of the nuclear spin bath, which allows us to observe by ensemble averaging macroscopically hidden polarization dynamics like Landau-Zener-Stückelberg oscillations. Moreover, we show that using the integrated solid effect both for single- and double-quantum transitions nuclear spin polarization can be achieved even when the static magnetic field is not aligned along the NV's crystal axis. This opens a path for the application of our DNP technique to spins in and outside of nanodiamonds, enabling their application as MRI tracers. Furthermore, the methods reported here can be applied to other solid state systems where a central electron spin is coupled to a nuclear spin bath, e.g., phosphor donors in silicon and color centers in silicon carbide.

  18. CIV Polarization Measurements Using a Vacuum Ultraviolet Fabry Perot

    Science.gov (United States)

    West, Edward A.

    2009-01-01

    Marshall Space Flight Center's (MSFC) is developing a Vacuum Ultraviolet (VUV) Fabry Perot that will be launched on a sounding rocket for high throughput, high-cadence, extended field of view CIV (155nm) measurements. These measurements will provide (i) Dopplergrams for studies of waves, oscillations, explosive events, and mass motions through the transition region, and, (ii), polarization measurements to study the magnetic field in the transition region. This paper will describe the scientific goals of the instrument, a brief description of the optics and the polarization characteristics of the VUV Fabry Perot.

  19. RHIC Polarized proton operation

    International Nuclear Information System (INIS)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.E.; Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-01-01

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP 4 . A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  20. RHIC Polarized proton operation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D' Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  1. DIGITAL SELF-OSCILLATING MODULATOR

    DEFF Research Database (Denmark)

    2007-01-01

    A digital self-oscillating modulator (1) having a digital reference signal as input (Vref) comprises a forward loop with a first output and a feedback loop. The feedback loop comprises a feedback block (18) having a transfer function (MFB) and a digital output. The forward loop comprises an alter......A digital self-oscillating modulator (1) having a digital reference signal as input (Vref) comprises a forward loop with a first output and a feedback loop. The feedback loop comprises a feedback block (18) having a transfer function (MFB) and a digital output. The forward loop comprises...

  2. Spontaneous oscillations in microfluidic networks

    Science.gov (United States)

    Case, Daniel; Angilella, Jean-Regis; Motter, Adilson

    2017-11-01

    Precisely controlling flows within microfluidic systems is often difficult which typically results in systems being heavily reliant on numerous external pumps and computers. Here, I present a simple microfluidic network that exhibits flow rate switching, bistablity, and spontaneous oscillations controlled by a single pressure. That is, by solely changing the driving pressure, it is possible to switch between an oscillating and steady flow state. Such functionality does not rely on external hardware and may even serve as an on-chip memory or timing mechanism. I use an analytic model and rigorous fluid dynamics simulations to show these results.

  3. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  4. Terahertz polarization imaging

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Van der Marel, W.A.M.; Planken, P.C.M.

    2005-01-01

    We present a new method to measure the polarization state of a terahertz pulse by using a modified electrooptic sampling setup. To illustrate the power of this method, we show two examples in which the knowledge of the polarization of the terahertz pulse is essential for interpreting the results:

  5. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  6. Polar Science Is Cool!

    Science.gov (United States)

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  7. TOWARDS THRESHOLD FREQUENCY IN CHAOTIC COLPITTS OSCILLATOR

    DEFF Research Database (Denmark)

    Lindberg, Erik; Tamasevicius, Arunas; Mykolaitis, Gytis

    2007-01-01

    A novel version of chaotic Colpitts oscillator is described. Instead of a linear loss resistor, it includes an extra inductor and diode in the collector circuit of the transistor. The modified circuit in comparison with the common Colpitts oscillator may generate chaotic oscillations at the funda......A novel version of chaotic Colpitts oscillator is described. Instead of a linear loss resistor, it includes an extra inductor and diode in the collector circuit of the transistor. The modified circuit in comparison with the common Colpitts oscillator may generate chaotic oscillations...

  8. Precision Polarization of Neutrons

    Science.gov (United States)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  9. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2018-01-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements. PMID:29503479

  10. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2017-10-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.

  11. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  12. Spin rotation and oscillations for high energy particles in a crystal and possibility to measure the quadrupole moments and tensor polarizabilities of elementary particles and nuclei

    OpenAIRE

    Baryshevsky, V. G.; Gurinovich, A. A.

    2005-01-01

    It is shown that particle motion in a bent (straight) crystal is accompanied by particle spin rotation and oscillations that allows to measure the tensor electric and magnetic polarizabilities of nuclei and elementary particles. It is shown that channelling of particles in either straight or bent crystal with the polarized nuclei could be used both to analyze polarization of high energy particles and polarize them.

  13. Strategic special nuclear material Inventory Differences. Semiannual report, April 1-September 30, 1984

    International Nuclear Information System (INIS)

    1985-07-01

    This sixteenth periodic semiannual report of Inventory Differences (ID) covers the last six months of fiscal year 1984 (April 1, 1984, through September 30, 1984), for the Department of Energy (DOE) and DOE contractor facilities possessing significant quantities of strategic special nuclear material (SSNM). Inventory Differences are simply the differences between the amount of material shown in the accounting records and the amount of material reported in the physical inventory. These differences are generally due to errors in estimating material in unmeasurable form at the time of an inventory, unmeasurable holdup in equipment, measurement imprecisions, inaccuracies in initial determinations of SSNM produced or used in nuclear reactors, and inventory or bookkeeping errors. Both DOE and contractors operating DOE facilities carefully maintain, analyze, and investigate ID data. Inventory Differences are expected in nuclear material processing and are not, in and of themselves, evidence of lost or stolen material. On the other hand, ID analysis provides valuable information on the effectiveness of the safeguards system's physical protection and material control measures as well as a check on the process controls and material management procedures. ID's outside safeguards control limits or involving a missing SSNM discrete item are investigated. If necessary, an operation may be shut down until an ID is resolved

  14. Fusion reactor materials semiannual progress report for period ending September 30, 1990

    International Nuclear Information System (INIS)

    1991-04-01

    This is the ninth in series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development of Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  15. Fusion Reactor Materials semiannual progress report for the period ending March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    This is the twelfth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  16. Fusion reactor materials semiannual progress report for the period ending March 31, 1991

    International Nuclear Information System (INIS)

    1991-07-01

    This is the tenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: alloy development for irradiation performance; damage analysis and fundamental studies; special purpose materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of program participants, and to provide a means of communicating the efforts of materials scientists to the test of the fusion community, both nationally and worldwide

  17. Semiannual report to Congress on Inspector General audit reports, October 1, 1996--March 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    This is the Secretary of Energy`s sixteenth Semiannual Report to Congress submitted under the Inspector General Act of 1978, as amended. Pursuant to the Inspector General Act Amendments of 1988 (Public law 100-504), agency heads are to report to Congress on the status of final action taken on audit report recommendations. This report complements a report prepared by the Department`s Office of Inspector General that provides information on audit reports issued during the period and on the status of management decisions made on Inspector General audit reports. During the period covered by this report, October 1, 1996, through March 31, 1997, the Department took final action on 31 operational, financial, and preaward audit reports. At the end of the period 74 reports awaited final action. Final action was taken on 11 contract and financial assistance audits, leaving no reports requiring final action at the end of the period. This report has three sections. The first section outlines significant audit resolution and followup accomplishments achieved by the Department during the reporting period. The second section contains the statistical tables that illustrate the status of final action on Inspector General audit reports. The third lists the audit reports that are one year or more past management decision and have not completed final action. This section also provides the status of corrective actions on each of those reports.

  18. Semiannual report to Congress on Inspector General audit reports, October 1, 1997--March 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    This is the Secretary of Energy`s eighteenth Semiannual Report to Congress submitted under the Inspector General Act of 1978, as amended. Pursuant to the Inspector General Act Amendments of 1988 (Public Law 100-504), agency heads are to report to Congress on the status of final action taken on audit report recommendations. This report complements a report prepared by the Department`s Office of Inspector General that provides information on audit reports issued during the period and on the status of management decisions made on Inspector General audit reports. During the period covered by this report, October 1, 1997, through March 31, 1998, the Department took final action on 20 operational, financial, and preaward audit reports. At the end of the period 80 reports awaited final action. Final action was taken on one contract and financial assistance audit, leaving two reports requiring final action at the end of the period. This report has three sections. The first section outlines significant audit resolution and followup accomplishments achieved by the Department during the reporting period. The second section contains the statistical tables that illustrate the status of final action on Inspector General audit reports. The third lists the audit reports that are one year or more past management decision and have not completed final action. This section also provides the status of corrective actions on each of those reports.

  19. Semi-annual technical report, September 30, 1999 - March 31, 2000

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Dorin

    2000-04-01

    The Consortium for Plant Biotechnology Research, Inc. (CPBR) continues to operate according to objectives outlined in the proposal funded through the cooperative agreement. The italicized objectives below are addressed in this report, which covers the period September 30,1999 through March 31, 2000. (1) Update the research agenda using information obtained from member companies. (2) Identify and implement research projects that are deemed by industrial, scientific, and sponsoring agency evaluation to address significantly the problems and future of U.S. energy resources and that are relevant to the Department of Energy's mission. Specifically: (1) Announce research grants competition through a Request for Preproposals. (2) Conduct a dual-stage review process: Stage one--industrial and DOE review of preproposals; and Stage two--peer review, scientific consultants' review, DOE review of full proposals and Project Recommendation Committee evaluation and recommendation for funding. (3) Board of Directors approval of recommended awards. (4) Conduct ongoing project management. (5) Obtain semiannual, annual and final reports for evaluation of research goals and technology transfer. (6) Present reports to DOE.

  20. Semiannual report to Congress on Inspector General audit reports, April 1, 1995--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    This is the Secretary of Energy`s thirteenth Semiannual Report to Congress submitted under the Inspector General Act of 1978, as amended. Pursuant to the Inspector General Act Amendments of 1988 (Public Law 100-504), agency heads are to report to Congress on the status of final action taken on audit report recommendations. This report complements a report prepared by the Department`s Office of Inspector General that provides information on audit reports issued during the period and on the status of management decisions made on Inspector General audit reports. During the period covered by this report, April 1, 1995, through September 30, 1995, the Department took final action on 33 operational, financial, and preaward audit reports. At the end of the period 96 reports awaited final action. Final action was taken on 2 contract and financial assistance audits, leaving 2 reports requiring final action at the end of the period. This report has three sections. The first section outlines significant audit resolution and followup accomplishments achieved by the Department during the reporting period. The second section contains the statistical tables that illustrate the status of final action on Inspector General audit reports. The third lists the audit reports that are one year or more past management decision and have not completed final action. This section also provides the status of corrective actions on each of these reports.

  1. Semiannual report to Congress on Inspector General audit reports, April 1--September 30, 1994

    International Nuclear Information System (INIS)

    1994-11-01

    This is the Secretary of Energy's eleventh Semiannual Report to Congress submitted under the Inspector General Act of 1978, as amended. Pursuant to the Inspector General Act Amendments of 1988 (Public Law 100-504), agency heads are to report to Congress on the status of final action taken on audit report recommendations. This report complements a report prepared by the Department's Office of Inspector General that provides information on audit reports issued during the period and on the status of management decisions made on Inspector General audit reports. During the period covered by this report, April 1, through September 30, 1994, the Department took final action on 40 operational, financial, and preaward audit reports. At the end of the period 77 reports awaited final action. No final action was taken on contract and financial assistance audits, leaving six reports requiring final action at the end of the period. This report has three sections. The first outlines significant audit resolution and followup accomplishment achieved by the Department during the reporting period. The second section contains the statistical tables that illustrate the status of final action on Inspector General audit reports. The third lists the audit reports that are one year or more past management decision and have not completed final action. This section also provides the status of corrective actions on each of these reports

  2. Four Mile Creek semi-annual sampling report, January 1993 sampling event

    International Nuclear Information System (INIS)

    1993-05-01

    From 1955 to 1988 low-level radioactive wastewater generated by chemical separation processes within the General Separations Area (GSA) was discharged to seepage basins in the F and H Areas of the Savannah River Site (SRS). These basins were designed to permit the infiltration of the process wastewaters. As wastewater percolated downward through the basins, chemical and radioactive constituents were retained or sequestered in the subsoils. An extensive study aimed at characterizing the groundwater seeping into Four Mile Creek and its associated seepline was conducted in 1988 and 1989 (Haselow et al. 1990). Results of this study suggested that contaminants leaching from the F and H Area seepage basins were impacting the Four Mile Creek wetland system. The seepage basins were closed in 1988 and capped and sealed in 1990. This effectively eliminated the source of the contaminants and the hydraulic head driving the migration of contaminants from the basins. It has been hypothesized that, after the elimination of the source and head, annual rainfall amounts would be sufficient to dilute and flush out contaminants remaining in the subsoils and groundwaters beneath the basins. Westinghouse Savannah River Company has designed a semi-annual sampling and analytical program for the Four Mile Creek (FMC) seepline and stream water to test the hypothesis. This report summarizes field monitoring activities from January 25, 1993 to February 4, 1993

  3. Space Power Program Semiannual Progress Report for period ending June 30, 1963

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1963-10-11

    This is a report of progress on the Oak Ridge National Laboratory's research and development program on nuclear power plants for electrical power production in space vehicles. The work is carried out under AEG Reactor Experiments, Fuels, and Materials, and Reactor Component programs. Research and development work is under way on the stainless steel boiling-potassium reactor and the Medium Power Reactor Experiment, boiling alkali metal heat transfer, high-temperature and refractory alloys, fuel material, and space reactor shielding, particularly in connection with SNAP 2, 8, 10, and 50. Many of these OREL efforts are directed toward the development of a specific type of power plant, but they also furnish a significant contribution of scientific and engineering information needed in other programs on advanced SNAP systems. Progress on research and development directly related to the Medium Power Reactor Experiment (MPRE) is presented mostly in Part I of this report. Progress on the MPRE will, in the future, be reported on a quarterly basis. The form of the reporting will alternate from MPRE Quarterly Progress Reports to Space Power Semiannual Progress Reports.

  4. Fusion materials semiannual progress report for the period ending December 31, 1996

    International Nuclear Information System (INIS)

    1997-04-01

    This is the twenty-first in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The report covers the following topics: vanadium alloys; silicon carbide composite materials; ferritic/martensitic steels; copper alloys and high heat flux materials; austenitic stainless steels; insulating ceramics and optical materials; solid breeding materials; radiation effects, mechanistic studies and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; and irradiation facilities, test matrices, and experimental methods

  5. Fusion materials semiannual progress report for the period ending December 31, 1997

    International Nuclear Information System (INIS)

    Burn, G.

    1998-03-01

    This is the twenty-third in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. A large fraction of this work, particularly in relation to fission reactor experiments, is carried out collaboratively with their partners in Japan, Russia, and the European Union. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  6. Fusion materials semiannual progress report for the period ending September 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    This is the sixteenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following Progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide. The individual papers in this paper have been cataloged separately elsewhere.

  7. The distribution of the annual and semiannual cycles in the tropics

    International Nuclear Information System (INIS)

    Sumathipala, W.L.

    1992-06-01

    The distributions of annual and semiannual cycles in the tropics are studied using outgoing long-wave radiation (OLR), and FGGE level III b wind data. Amplitudes and variances of first and second harmonics (in the time domain) of low level zonal wind (U) are largest over monsoon regions of the eastern hemisphere and account for more than 80% of the variance. The first harmonic of OLR shows largest amplitudes over the continental regions between 10-15 degrees from the equator. The first harmonics of both low-level wind and OLR show standing character. The second and third harmonics of U are characterized by cross equatorial and clockwise phase propagation. All three harmonics are ''phase locked'' in the monsoon region of the eastern hemisphere during summer. Amplitude of the first harmonic of low level meridonal wind (V) is prominent at the Somalia coast and Malaysia. Amplitude variations of first and second harmonics of upper level zonal wind exhibit the response of subtropical jet streams to monsoon and inter-monsoon convective activity. Fairly strong amplitudes of OLR are found over the equatorial land areas where rainfall is maximum during the transition periods. (author). 15 refs, 7 figs

  8. Fusion reactor materials semiannual progress report for period ending September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    This is the ninth in series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development of Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  9. Fusion materials semiannual progress report for the period ending March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This is the eighteenth in a series of semiannual technical progress reports on fusion materials. This report combines research and development activities which were previously reported separately in the following progress reports: {sm_bullet} Alloy Development for Irradiation Performance. {sm_bullet} Damage Analysis and Fundamental Studies. {sm_bullet} Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide. This report has been compiled and edited under the guidance of A.F. Rowcliffe by Gabrielle Burn, Oak Ridge National Laboratory. Their efforts, and the efforts of the many persons who made technical contributions, are gratefully acknowledged.

  10. Fusion reactor materials semiannual progress report for the period ending March 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1991-07-01

    This is the tenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: alloy development for irradiation performance; damage analysis and fundamental studies; special purpose materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of program participants, and to provide a means of communicating the efforts of materials scientists to the test of the fusion community, both nationally and worldwide.

  11. NRC regulatory agenda: Semiannual report, January--June 1995. Volume 14, Number 1

    International Nuclear Information System (INIS)

    1995-09-01

    The Regulatory Agenda is a semiannual compilation of all rules on which the NRC has recently completed action, or has proposed action, or is considering action, and of all petitions for rulemaking that the NRC has received that are pending disposition. The agenda consists of two sections that have been updated through June 30, 1995. Section 1, ''Rules,'' includes (A) rules on which final action has been taken since December 30, 1994, the closing date of the last NRC Regulatory Agenda; (B) rules published previously as proposed rules on which the Commission has not taken final action; (C) rules published as advance notices of proposed rulemaking for which neither a proposed nor final rule has been issued; and (D) unpublished rules on which the NRC expects to take action. Section 2, ''Petitions for Rulemaking,'' includes (A) petitions denied or incorporated into final rules since December 30, 1994; (B) petitions incorporated into proposed rules; (C) petitions pending staff review, and (D) petitions with deferred action

  12. Semiannual report to Congress on Inspector General audit reports: April 1--September 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    This is the Secretary of Energy`s seventeenth Semiannual Report to Congress submitted under the Inspector General Act of 1978, as amended. Pursuant to the Inspector General Act Amendments of 1988 (Public Law 100-504), agency heads are to report to Congress on the status of final action taken on audit report recommendations. This report complements a report prepared by the Department`s Office of Inspector General that provides information on audit reports issued during the period and on the status of management decisions made on Inspector General audit reports. During the period covered by this report, April 1 through September 30, 1997, the Department took final action on 29 operational, financial, and preaward audit reports. At the end of the period 72 reports awaited final action. Final action was taken on five contract and financial assistance audits, leaving two reports requiring final action at the end of the period. This report has three sections. The first section outlines significant audit resolution and followup accomplishments achieved by the Department during the reporting period. The second section contains the statistical tables that illustrate the status of final action on Inspector General audit reports. The third lists the audit reports that are one year or more past management decision and have not completed final action. This section also provides the status of corrective actions on each of those reports.

  13. Ellipsoidal basis for isotropic oscillator

    International Nuclear Information System (INIS)

    Kallies, W.; Lukac, I.; Pogosyan, G.S.; Sisakyan, A.N.

    1994-01-01

    The solutions of the Schroedinger equation are derived for the isotropic oscillator potential in the ellipsoidal coordinate system. The explicit expression is obtained for the ellipsoidal integrals of motion through the components of the orbital moment and Demkov's tensor. The explicit form of the ellipsoidal basis is given for the lowest quantum numbers. 10 refs.; 1 tab. (author)

  14. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    Abstract. Oscillating solitons are obtained in nonlinear optics. Analytical study of the variable- coefficient nonlinear Schrödinger equation, which is used to describe the soliton propagation in those systems, is carried out using the Hirota's bilinear method. The bilinear forms and analytic soliton solutions are derived, and the ...

  15. Low-Vibration Oscillating Compressor

    Science.gov (United States)

    Studer, P. A.

    1984-01-01

    Oscillating compressor momentum compensated: produces little vibration in its supporting structure. Compressure requires no lubrication and virtually free of wear. Compresses working fluids such as helium, nitrogen or chlorfluorocarbons for Stirling-cycle refrigeration or other purposes. Compressor includes two mutually opposed ferromagnetic pistons of same shape and mass. Electromagnetic flux links both pistons, causing magnetic attraction between them.

  16. Sound oscillation of dropwise cluster

    Energy Technology Data Exchange (ETDEWEB)

    Shavlov, A.V., E-mail: shavlov@ikz.ru [Institute of the Earth Cryosphere, RAS Siberian Branch, P.O. 1230, 625000 Tyumen (Russian Federation); Dzhumandzhi, V.A.; Romanyuk, S.N. [Institute of the Earth Cryosphere, RAS Siberian Branch, P.O. 1230, 625000 Tyumen (Russian Federation)

    2012-06-04

    There was registered sound oscillation of a dropwise cluster formed over the warmed-up water surface. We have calculated the electrical charge of drops on the basis of experimental data on ion-sound oscillation. It was demonstrated that the charge is proportional to surface area of the drops and does not depend on intensity of their evaporation (condensation) in the range of 60–100 °C. The charge of drops reaches 10{sup 2}–10{sup 3} units of elementary charge and coincides on magnitude order with the literary value of a charge calculated by another method. -- Highlights: ► The present investigation registered short-wave sound oscillations of water drops in a dropwise cluster in the range of 60–100 °C. ► We have found autocorrelation functions and Fourier transforms of time series of interdroplet distance; defined oscillation frequencies. ► Calculated electrical charge of drops and specified that the charge is proportional to the drop surface area.

  17. Sound oscillation of dropwise cluster

    International Nuclear Information System (INIS)

    Shavlov, A.V.; Dzhumandzhi, V.A.; Romanyuk, S.N.

    2012-01-01

    There was registered sound oscillation of a dropwise cluster formed over the warmed-up water surface. We have calculated the electrical charge of drops on the basis of experimental data on ion-sound oscillation. It was demonstrated that the charge is proportional to surface area of the drops and does not depend on intensity of their evaporation (condensation) in the range of 60–100 °C. The charge of drops reaches 10 2 –10 3 units of elementary charge and coincides on magnitude order with the literary value of a charge calculated by another method. -- Highlights: ► The present investigation registered short-wave sound oscillations of water drops in a dropwise cluster in the range of 60–100 °C. ► We have found autocorrelation functions and Fourier transforms of time series of interdroplet distance; defined oscillation frequencies. ► Calculated electrical charge of drops and specified that the charge is proportional to the drop surface area.

  18. The Quasi-Biennial Vertical Oscillations at Global GPS Stations: Identification by Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Yuanjin Pan

    2015-10-01

    Full Text Available Modeling nonlinear vertical components of a GPS time series is critical to separating sources contributing to mass displacements. Improved vertical precision in GPS positioning at stations for velocity fields is key to resolving the mechanism of certain geophysical phenomena. In this paper, we use ensemble empirical mode decomposition (EEMD to analyze the daily GPS time series at 89 continuous GPS stations, spanning from 2002 to 2013. EEMD decomposes a GPS time series into different intrinsic mode functions (IMFs, which are used to identify different kinds of signals and secular terms. Our study suggests that the GPS records contain not only the well-known signals (such as semi-annual and annual signals but also the seldom-noted quasi-biennial oscillations (QBS. The quasi-biennial signals are explained by modeled loadings of atmosphere, non-tidal and hydrology that deform the surface around the GPS stations. In addition, the loadings derived from GRACE gravity changes are also consistent with the quasi-biennial deformations derived from the GPS observations. By removing the modeled components, the weighted root-mean-square (WRMS variation of the GPS time series is reduced by 7.1% to 42.3%, and especially, after removing the seasonal and QBO signals, the average improvement percentages for seasonal and QBO signals are 25.6% and 7.5%, respectively, suggesting that it is significant to consider the QBS signals in the GPS records to improve the observed vertical deformations.

  19. North-south asymmetry of ultra-low-frequency oscillations of Earth's electromagnetic field

    Science.gov (United States)

    Guglielmi, Anatol; Klain, Boris; Potapov, Alexander

    2017-12-01

    In the paper, we present the result of an experimental study of north-south asymmetry of ultralow-frequency electromagnetic oscillations IPCL. This study is based on observations made at Mirny Observatory (Antarctica). IPCLs are excited in the dayside sector of the auroral oval in the range 3-10 min periods and represent one of the most powerful types of oscillations of Earth's magnetosphere. These oscillations were discovered in the 1970s during IPhE AS USSR polar expeditions organized by Prof. V.A. Troitskaya. We have shown that IPCL activity in Mirny depends on the inclination (north-south asymmetry) of interplanetary magnetic field (IMF) lines to the plane of the geomagnetic equator before the front of the magnetosphere. The result suggests a controlling exposure of IMF on the magnetospheric oscillations and gives rise to the hypothesis that IPCLs are forced oscillations of a nonlinear dynamical system whose major structural elements are dayside polar cusps. The paper is dedicated to the memory of Professor V.A. Troitskaya (1917-2010).

  20. Polarization at the SLC

    Energy Technology Data Exchange (ETDEWEB)

    Moffeit, K.C.

    1988-10-01

    The Stanford Linear collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z/sup 0/ mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Moller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. 8 refs., 16 figs., 1 tab.

  1. Characterizing brain oscillations in cognition and disease

    NARCIS (Netherlands)

    Jiang, H.

    2016-01-01

    It has been suggested that neuronal oscillations play a fundamental role for shaping the functional architecture of the working brain. This thesis investigates brain oscillations in rat, human healthy population and major depressive disorder (MDD) patients. A novel measurement termed

  2. Cyanohydrin reactions enhance glycolytic oscillations in yeast

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Nielsen, Astrid Gram; Tortzen, Christian

    2015-01-01

    Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here...

  3. Analytic Neutrino Oscillation Probabilities in Matter: Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Parke, Stephen J. [Fermilab; Denton, Peter B. [Copenhagen U.; Minakata, Hisakazu [Madrid, IFT

    2018-01-02

    We summarize our recent paper on neutrino oscillation probabilities in matter, explaining the importance, relevance and need for simple, highly accurate approximations to the neutrino oscillation probabilities in matter.

  4. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  5. Internal dynamics of long Josephson junction oscillators

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Lomdahl, P. S.; Scott, Alwyn C.

    1981-01-01

    Numerical computations on a sine-Gordon model of the Josephson junction fluxon oscillator are compared with experimental measurements. Good agreement is found for the voltage current characteristic, oscillator power output, and range of current bias over which oscillation is observed. Our numeric...... results imply a ''bunched-fluxon'' mode of oscillation at larger values of bias current. Applied Physics Letters is copyrighted by The American Institute of Physics....

  6. Nonlinear analysis of ring oscillator circuits

    KAUST Repository

    Ge, Xiaoqing

    2010-06-01

    Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.

  7. A theory of generalized Bloch oscillations

    DEFF Research Database (Denmark)

    Duggen, Lars; Lew Yan Voon, L. C.; Lassen, Benny

    2016-01-01

    Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact...... oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics....

  8. Polarized scintillator targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2000-05-01

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as "live" polarized targets in nuclear physics experiments.

  9. Polarized scintillator targets

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den E-mail: vandenbrandt@psi.ch; Bunyatova, E.I.; Hautle, P.; Konter, J.A.; Mango, S

    2000-05-21

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as 'live' polarized targets in nuclear physics experiments.

  10. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

    Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

    1984-01-01

    A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

  11. One- to two-month oscillations in SSMI surface wind speed in western tropical Pacific Ocean

    Science.gov (United States)

    Collins, Michael L.; Stanford, John L.; Halpern, David

    1994-01-01

    The 10-m wind speed over the ocean can be estimated from microwave brightness temperature measurements recorded by the Special Sensor Microwave Imager (SSMI) instrument mounted on a polar-orbiting spacecraft. Four-year (1988-1991) time series of average daily 1 deg x 1 deg SSMI wind speeds were analyzed at selected sites in the western tropical Pacific Ocean. One- to two-month period wind speed oscillations with amplitudes statistically significant at the 95% confidence level were observed near Kanton, Eniwetok, Guam, and Truk. This is the first report of such an oscillation in SSMI wind speeds.

  12. The role of amplitude-to-phase conversion in the generation of oscillator flicker phase noise

    Science.gov (United States)

    Hearn, C. P.

    1985-01-01

    The role of amplitude-to-phase conversion as a factor in feedback oscillator flicker phase noise is examined. A limiting stage consisting of parallel-connected opposite polarity diodes operating in a circuit environment contining reactance is shown to exhibit amplitude-to-phase conversion. This mechanism coupled with resistive upconversion provides an indirect route for very low frequency flicker noise to be transferred into the phase of an oscillator signal. It is concluded that this effect is more significant in the lower frequency regimes where the onlinear reactances associated with active devices are overwhelmed by linear reactive elements.

  13. Polarization measurement in the COMPASS polarized target

    CERN Document Server

    Kondo, K; Baum, G; Berglund, P; Doshita, N; Gautheron, F; Görtz, S; Hasegawa, T; Horikawa, N; Ishimoto, S; Iwata, T; Kisselev, Yu V; Koivuniemi, J H; Le Goff, J M; Magnon, A; Meyer, W; Reicherz, G; Matsuda, T

    2004-01-01

    Continuous wave nuclear magnetic resonance (NMR) is used to determine the target polarization in the COMPASS experiment. The system is made of the so-called Liverpool Q-meters, Yale-cards, and VME modules for data taking and system controlling. In 2001 the NMR coils were embedded in the target material, while in 2002 and 2003 the coils were mounted on the outer surface of the target cells to increase the packing factor of the material. Though the error of the measurement became larger with the outer coils than with the inner coils, we have performed stable measurements throughout the COMPASS run time for 3 years. The maximum polarization was +57% and -53% as the average in the target cells.

  14. Effective harmonic oscillator description of anharmonic molecular ...

    Indian Academy of Sciences (India)

    Administrator

    The effective harmonic oscillator is constructed variationally, by taking the trial wave function as a harmonic oscillator eigenfunction with the centroid and width parameter as variational para- eters. It is found that the effective harmonic oscillator approximation provides a description of the anharmonic eigenstates very similar ...

  15. Assessing the quality of stochastic oscillations

    Indian Academy of Sciences (India)

    Population dynamics; stochastic oscillations. ... We propose a quantification of the oscillatory appearance of the fluctuating populations, and show that good stochastic oscillations are present if a parameter of the macroscopic model is small, and that no microscopic model will show oscillations if that parameter is large.

  16. Neutrino oscillations in the early universe

    International Nuclear Information System (INIS)

    Enqvist, K.

    1990-01-01

    The oscillations of electron neutrinos into inert neutrinos may have resonant behaviour in the heat bath of the early Universe. It is shown that any initial neutrino asymmetry will be washed away by the oscillations. Neutrino oscillations would affect also primordial helium production, which implies stringent limits on the neutrino mixing parameters. (orig.)

  17. The supersymmetric Pegg-Barnett oscillator

    International Nuclear Information System (INIS)

    Shen, Jian Qi

    2005-01-01

    The su(n) Lie algebraic structure of the Pegg-Barnett oscillator that possesses a finite-dimensional number-state space is demonstrated. The supersymmetric generalization of the Pegg-Barnett oscillator is suggested. it is shown that such a supersymmetric Pegg-Barnett oscillator may have some potential applications, e.g., the mass spectrum of the charged leptons

  18. Dependence of synchronization frequency of Kuramoto oscillators ...

    Indian Academy of Sciences (India)

    journal of. December 2014 physics pp. 945–953. Dependence of synchronization frequency of Kuramoto oscillators on symmetry of intrinsic frequency in ring ... In this article, we study the difference between networks with sym- ... The dynamics of a general ith oscillator in a system of N Kuramoto oscillators is given as.

  19. Three flavour oscillation interpretation of neutrino data

    Indian Academy of Sciences (India)

    To explain the atmospheric neutrino problem in terms of neutrino oscillations, ЖС¾ of about 10-¿. eV. ¾. [8] is needed whereas the neutrino oscil- lation solution to the solar neutrino problem requires ЖС¾ ~10- eV. ¾ . Hence both solar and atmospheric neutrino problems cannot be explained in terms of e ° μ oscillations.

  20. Comparison of Methods for Oscillation Detection

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Trangbæk, Klaus

    2006-01-01

    This paper compares a selection of methods for detecting oscillations in control loops. The methods are tested on measurement data from a coal-fired power plant, where some oscillations are occurring. Emphasis is put on being able to detect oscillations without having a system model and without u...

  1. Semi-annual status report of the Canadian Nuclear Fuel Waste Management Program, April 1--September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Wright, E.D. [comp.

    1992-02-01

    This report is the eleventh in a series of semi-annual status reports on the research and development program for the safe management and disposal of Canada's nuclear fuel waste. it describes progress achieved in the three major subprograms, engineered systems, natural systems and performance assessment, from 1991 April 1 to September 30. It also gives a brief description of the activities being carried out in preparation for the public and governmental review of the disposal concept. Since 1987, this program has been jointly funded by AECL and Ontario Hydro under the auspices of the CANDU Owners Group (COG).

  2. Semiannual Report of the Chemistry Department, June--November 1966; Rapport semestriel du departement de chimie, juin--novembre 1966

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1967-07-01

    This semiannual report of the Chemistry Department of the Cea of Fontenay-aux Roses, presents in its first part researches on the chemical analysis, the treatment of fairly and slightly active effluents, the uranium treatment, studies on electrometallurgy, studies on corrosion and studies on filtration and elimination on sea water of hard compounds. The second part is devoted to the study of aqueous reprocessing of irradiated fuels (laboratory and pilot plant), anhydrous reprocessing, actinides elements isotopes preparation and study, fission products concentrated solution vitrification study and fundamental studies on acid-base properties. (A.L.B.)

  3. Berry phase and shot noise for spin-polarized and entangled electrons

    International Nuclear Information System (INIS)

    Wang Pei; Tang Weihua; Lu Dinghui; Jiang Lixia; Zhao Xuean

    2007-01-01

    Shot noise for entangled and spin-polarized states in a four-probe geometric setup has been studied by adding two rotating magnetic fields in an incoming channel. Our results show that the noise power oscillates as the magnetic fields vary. The singlet, entangled triplet and polarized states can be distinguished by adjusting the magnetic fields. The Berry phase can be derived by measuring the shot noise power

  4. Measuring neutrino oscillation parameters using $\

    Energy Technology Data Exchange (ETDEWEB)

    Backhouse, Christopher James [Oriel College, Oxford (United Kingdom)

    2011-01-01

    MINOS is a long-baseline neutrino oscillation experiment. It consists of two large steel-scintillator tracking calorimeters. The near detector is situated at Fermilab, close to the production point of the NuMI muon-neutrino beam. The far detector is 735 km away, 716m underground in the Soudan mine, Northern Minnesota. The primary purpose of the MINOS experiment is to make precise measurements of the 'atmospheric' neutrino oscillation parameters (Δmatm2 and sin2atm). The oscillation signal consists of an energy-dependent deficit of vμ interactions in the far detector. The near detector is used to characterize the properties of the beam before oscillations develop. The two-detector design allows many potential sources of systematic error in the far detector to be mitigated by the near detector observations. This thesis describes the details of the vμ-disappearance analysis, and presents a new technique to estimate the hadronic energy of neutrino interactions. This estimator achieves a significant improvement in the energy resolution of the neutrino spectrum, and in the sensitivity of the neutrino oscillation fit. The systematic uncertainty on the hadronic energy scale was re-evaluated and found to be comparable to that of the energy estimator previously in use. The best-fit oscillation parameters of the vμ-disappearance analysis, incorporating this new estimator were: Δm2 = 2.32-0.08+0.12 x 10-3 eV2, sin 2 2θ > 0.90 (90% C.L.). A similar analysis, using data from a period of running where the NuMI beam was operated in a configuration producing a predominantly $\\bar{v}$μ beam, yielded somewhat different best-fit parameters Δ$\\bar{m}${sup 2} = (3.36-0.40+0.46(stat.) ± 0.06(syst.)) x 10-3eV2, sin2 2$\\bar{θ}$ = 0.86-0.12_0

  5. Time domain oscillating poles: Stability redefined in Memristor based Wien-oscillators

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2012-07-28

    Traditionally, the necessary and sufficient condition for any system to be oscillating is that its poles are located on the imaginary (jω) axis. In this paper, for the first time, we have shown that systems can oscillate with time-domain oscillating poles. The idea is verified using a Memristor based Wien oscillator. Sustained oscillations are observed without having the poles of the system fixed on the imaginary axis and the oscillating behavior of the system poles is reported. The oscillating resistance and triangular shape of FFT are also demonstrated with mathematical reasoning and simulation results to support the unusual and surprising characteristics. © 2009 IEEE.

  6. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H.B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  7. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......%. Furthermore, the presence of low-pass filters in time-domain-induced polarization instruments affects the early times of the acquired decays (typically up to 100 ms) and has to be modeled in the forward response to avoid significant loss of resolution. The developed forward code has been implemented in a 1D...

  8. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  9. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  10. Ultracold Polar Molecules

    Science.gov (United States)

    2016-04-01

    AFRL-AFOSR-UK-TR-2016-0005 Ultracold Polar Molecules Jeremy Hutson UNIVERSITY OF DURHAM Final Report 04/01/2016 DISTRIBUTION A: Distribution approved...DATES COVERED (From - To) 15-Jan-2010 to 14-Jul-2015 4. TITLE AND SUBTITLE Final Report on Grant FA8655-10-1-3033 on Ultracold Polar Molecules 5a...formation of ultracold 87RbCs molecules in their rovibrational ground state by magnetoassociation followed by STIRAP, resulting in 14 papers acknowledging

  11. Hsp Polarization Verification

    Science.gov (United States)

    Bless, Robert

    1991-07-01

    This proposal defines the procedure for determining the instrumental polarization of the polarimetric IDT (IDT#1, POL) on the HSP. 1 of 2 unpolarized standard stars wil be observed using various filter-polarizer combinations. These observations will permit the instrumental polarization to be calibrated. The instrumental polarization must be determined to a high precision in order to vectoriallly remove it from HSP polarization observations to determine the actual astronomical polarization. Final run of proposal will look at one of 2 possible stars previously observed to get another look at the throughput. Revision History: Mark H. Slovak 8/30/88 Translated to V2 proposal instructions (RPSS V6.2) S. Laurent 1/20/89 Updated: Sally Laurent 2/24/89, 3/20/89, 4/13/89, 5/12/89 Modified: P. Stanley 1/15/90 - change to use CTA selected targets only; Fixes for aberration problem - SALM 7/30/90; Based on SV/HSP 1386. New submission changed targets and revised scheduling strategy. Revised: 26 Aug 92 J. Dolan, L. Walter, P. Reppert want to re-run the proposal (3985) one last time to bring down errors.

  12. Thermoelastic loss in microscale oscillators

    Science.gov (United States)

    Houston, B. H.; Photiadis, D. M.; Marcus, M. H.; Bucaro, J. A.; Liu, Xiao; Vignola, J. F.

    2002-02-01

    A simple model of thermoelastic dissipation is proposed for general, free standing microelectromechanical (MEMS) and nanoelectromechanical (NEMS) oscillators. The theory defines a flexural modal participation factor, the fraction of potential energy stored in flexure, and approximates the internal friction by assuming the energy loss to occur solely via classical thermoelastic dissipation of this component of the motion. The theory is compared to the measured internal friction of a high Q mode of a single-crystal silicon double paddle oscillator. The loss at high temperature (above 150 K) is found to be in good agreement with the theoretical prediction. The importance of this dissipation mechanism as a function of scale is briefly discussed. We find that the relative importance of this mechanism scales with the size of the structure, and that for nanoscale structures it is less important than intrinsic phonon-phonon scattering.

  13. Neuronal oscillations in Parkinson's disease.

    Science.gov (United States)

    Witcher, Mark; Moran, Rosalyn; Tatter, Stephen B; Laxton, Adrian W

    2014-06-01

    Parkinson's Disease (PD), characterized by tremor, rigidity, and bradykinesia, is one of the most prevalent neurodegenerative disorders in the world. The pathological hallmark of PD is the loss of dopaminergic cells in the substantia nigra and other brain regions. The pathophysiological mechanisms by which dopaminergic cell loss leads to the motor manifestations of PD are yet to be fully elucidated. A growing body of evidence has revealed abnormal neuronal oscillations within and between multiple brain regions in PD. Unique oscillatory patterns are associated with specific motor abnormalities in PD. Therapies, such as dopaminergic medication and deep brain stimulation that disrupt these abnormal neuronal oscillatory patterns produce symptomatic improvement in PD patients. These findings emphasize the importance of abnormal neuronal oscillations in the pathophysiology of PD, making the disruption of these oscillatory patterns a promising target in the development of effective PD treatments.

  14. Neutrino oscillations in deconstructed dimensions

    International Nuclear Information System (INIS)

    Haellgren, Tomas; Ohlsson, Tommy; Seidl, Gerhart

    2005-01-01

    We present a model for neutrino oscillations in the presence of a deconstructed non-gravitational large extra dimension compactified on the boundary of a two-dimensional disk. In the deconstructed phase, sub-mm lattice spacings are generated from the hierarchy of energy scales between ∼ 1 TeV and the usual B-L breaking scale ∼ 10 15 GeV. Here, short-distance cutoffs down to ∼ 1 eV are motivated by the strong coupling behavior of gravity in local discrete extra dimensions. This could make it possible to probe the discretization of extra dimensions and non-trivial field configurations in theory spaces which have only a few sites, i.e., for coarse latticizations. Thus, the model has relevance to present and future precision neutrino oscillation experiments. (author)

  15. Experimental studies of neutrino oscillations

    CERN Document Server

    Kajita, Takaaki

    2016-01-01

    The 2015 Nobel Prize in physics has been awarded to Takaaki Kajita and Arthur McDonald "for the discovery of neutrino oscillations, which shows that neutrinos have mass". Takaaki Kajita of Tokyo University is a Japanese physicist, known for neutrino experiments at the Kamiokande and its successor, Super-Kamiokande. This volume of collected works of Kajita on neutrino oscillations provides a good glimpse into as well as a record of the rise and the role of Asian research in the frontiers of neutrino physics. Japan is now a major force in the study of the 3 families of neutrinos. Much remains to be done to clarify the Dirac vs. Majorana nature of the neutrino, and the cosmological implications of the neutrino. The collected works of Kajita and his Super-Kamiokande group will leave an indelible foot-print in the history of big and better science.

  16. Memristor-based reactance-less oscillator

    KAUST Repository

    Zidan, Mohammed A.

    2012-10-02

    The first reactance-less oscillator is introduced. By using a memristor, the oscillator can be fully implemented on-chip without the need for any capacitors or inductors, which results in an area-efficient fully integrated solution. The concept of operation of the proposed oscillator is explained and detailed mathematical analysis is introduced. Closed-form expressions for the oscillation frequency and oscillation conditions are derived. Finally, the derived equations are verified with circuit simulations showing excellent agreement. © 2011 The Institution of Engineering and Technology.

  17. Quantum oscillations of conductivity in bismuth wires

    International Nuclear Information System (INIS)

    Condrea, Elena

    2011-01-01

    Measurements of the resistance of bismuth nanowires with several diameters and different quality reveal oscillations on the dependence of resistance under uniaxial strain at T = 4.2 K. Amplitude of oscillations is significant (38 %) at helium temperature and becomes smearing at T = 77 K. Observed oscillations originate from quantum size effect. A simple evaluation of period of oscillations allows us to identify the groups of carriers involved in transport. Calculated periods of 42.2 and 25.9 nm satisfy approximately the ratio 2:1 for two experimentally observed sets of oscillations from light and heavy electrons.

  18. Harmonic oscillator and nuclear pseudospin

    International Nuclear Information System (INIS)

    Lisboa, Ronai; Malheiro, Manuel; Castro, Antonio S. de; Alberto, Pedro; Fiolhais, Manuel

    2004-01-01

    A generalized relativistic harmonic oscillator for spin 1/2 particles is studied. The Dirac Hamiltonian contains a scalar S and a vector V quadratic potentials in the radial coordinate, as well as a tensor potential U, linear in r. Setting either Σ = S + V or Δ = V - S to zero, analytical solutions for bound states are found. The eingenenergies and their nonrelativistic limits are presented and particular cases are discussed, especially the case Σ = 0, for which pseudospin symmetry is exact

  19. Global Status of Neutrino Oscillation

    Indian Academy of Sciences (India)

    monojit

    Number Games. The defining element in the oscillation (or survival probability) is sin. 2. ∆m2. 21L/(4E) ≡ sin. 2. 1.27(∆m2. 21eV. 2) ((L/E)km/GeV OR m/MeV). .... The 90% CL contours with 10 years' simulated ICAL in comparison with results ... Simulation showing improvement in sensitivity to the unknown CP phase.

  20. Harmonic oscillator on a lattice

    International Nuclear Information System (INIS)

    Ader, J.P.; Bonnier, B.; Hontebeyrie, M.; Meyers, C.

    1983-01-01

    The continuum limit of the ground state energy for the harmonic oscillator with discrete time is derived for all possible choices of the lattice derivative. The occurrence of unphysical values is shown to arise whenever the lattice laplacian is not strictly positive on its Brillouin zone. These undesirable limits can either be finite and arbitrary (multiple spectrum) or infinite (overlapping sublattices with multiple spectrum). (orig.)

  1. Lepton asymmetries from neutrino oscillations

    International Nuclear Information System (INIS)

    Volkas, R.R.

    2000-01-01

    Reasonably large relic neutrino asymmetries can be generated by active-sterile neutrino oscillations. After briefly discussing possible applications, I describe the Quantum Kinetic Equation formalism used to compute the asymmetry growth curves. I then show how the basic features of these curves can be understood on the basis of the adiabatic limit approximation in the collision dominated epoch, and the pure MSW effect at lower temperatures (author)

  2. Coherence effects in neutrino oscillations

    International Nuclear Information System (INIS)

    Kiers, K.; Weiss, N.

    1996-01-01

    We study the effect of coherent and incoherent broadening on neutrino oscillations both in vacuum and in the presence of matter (the MSW effect). We show under very general assumptions that it is not possible to distinguish experimentally neutrinos produced in some region of space as wave packets from those produced in the same region of space as plane waves with the same energy distribution. copyright 1995 The American Physical Society

  3. Oscillations and Waves in Sunspots

    Directory of Open Access Journals (Sweden)

    Elena Khomenko

    2015-11-01

    Full Text Available A magnetic field modifies the properties of waves in a complex way. Significant advances have been made recently in our understanding of the physics of sunspot waves with the help of high-resolution observations, analytical theories, as well as numerical simulations. We review the current ideas in the field, providing the most coherent picture of sunspot oscillations as by present understanding.

  4. Neutrino Oscillation Experiment at JHF

    CERN Multimedia

    2002-01-01

    T2K is a long baseline neutrino experiment designed to investigate how neutrinos change from one flavor to another as they travel (neutrino oscillations). An intense beam of muon neutrinos is generated at the J-PARC nuclear physics site on the East coast of Japan and directed across the country to the Super-Kamiokande neutrino detector in the mountains of western Japan. The beam is measured once before it leaves the J-PARC site, using the near detector ND280, and again at Super-K, 295 km away: the change in the measured intensity and composition of the beam is used to provide information on the properties of neutrinos. The high intensity neutrino beam is produced in an off-axis configuration. The peak neutrino energy is tuned to the oscillation maximum of ∼ 0.6 GeV to maximize the sensitivity to neutrino oscillations. The science goals of T2K can be summarized as follows: •\tsearch for CP violation in the neutrino sector •\tdiscovery of νμ → νe ( i.e. the confirmation that θ13 > 0 ) •\tprecision ...

  5. Drifting oscillations in axion monodromy

    International Nuclear Information System (INIS)

    Flauger, Raphael; Westphal, Alexander

    2014-12-01

    We study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. We use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.

  6. Micro-machined resonator oscillator

    Science.gov (United States)

    Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

    1994-01-01

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

  7. Drifting oscillations in axion monodromy

    Energy Technology Data Exchange (ETDEWEB)

    Flauger, Raphael [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); McAllister, Liam [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Silverstein, Eva [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States); Westphal, Alexander, E-mail: flauger@physics.ucsd.edu, E-mail: mcallister@cornell.edu, E-mail: evas@stanford.edu, E-mail: alexander.westphal@desy.de [Theory Group, Deutsches Elektronen-Synchrotron DESY, D-22603 Hamburg (Germany)

    2017-10-01

    We study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. We use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.

  8. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  9. Advanced Processing Technology semiannual report, March--December 1991. Volume 1, Number 1

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, M.; Kline-Simon, K. [eds.

    1991-12-31

    This first issue of the APT Semiannual Report focuses on APT`s defense-related technologies. These technologies are a continuation of the research, development, and engineering work performed by LLNLs Special Isotope Separation (SIS) Program. SIS was the first large-scale DOE venture that had environmentally conscious manufacturing processes and facilities as its deliverables. The objectives were to create a facility where the only outputs were either usable products or disposable wastes, and to comply with existing and anticipated federal, state, and local regulations related to safeguards, security, health and safety. To meet these objectives, revolutionary changes were needed in plutonium processing operations, chemistry, and equipment. New processes had to be developed that enhanced worker safety, minimized operator radiation dose, minimized waste at the point of generation, and provided for built-in recycling of residues. The SIS Program developed and demonstrated the technology (both chemistry and physics) necessary to provide plutonium with individual isotopic tailoring. This process made it possible to transform fuel-grade plutonium into weapon-grade material. However, due to the changing world political climate, the country`s need for plutonium to make new weapons has decreased dramatically. As a result, the planned SIS plutonium-separation plant will not be built. After the SIS Program was canceled in 199 1, Congress directed that the plutonium processing technologies under development for the SIS Program be redirected to the weapons program. APT took over the development of the innovative SIS technologies and is applying them to the development of a new, reconfigured Nuclear Weapons Complex -- Complex 21. ``Close Out of the SIS Program`` describes the completion of the SIS research and development work, and the transfer of key technologies to support this reconfiguration effort.

  10. Orienting Asymmetric Molecules by Laser Fields with Twisted Polarization

    Science.gov (United States)

    Gershnabel, E.; Averbukh, I. Sh.

    2018-02-01

    We study interaction of generic asymmetric molecules with laser fields having twisted polarization, using a pair of strong time-delayed short laser pulses with crossed linear polarizations as an example. We show that such an excitation not only provides unidirectional rotation of the most polarizable molecular axis, but also induces a directed torque along this axis, which results in a transient orientation of the molecules. The asymmetric molecules are chiral in nature and different molecular enantiomers experience the orienting action in opposite directions causing out-of-phase oscillations of their dipole moments. The resulting microwave radiation was recently suggested to be used for analysis or discrimination of chiral molecular mixtures. We reveal the mechanism behind this laser-induced orientation effect, show that it is classical in nature, and envision further applications of light with twisted polarization.

  11. The evolution of tensor polarization

    International Nuclear Information System (INIS)

    Huang, H.; Lee, S.Y.; Ratner, L.

    1993-01-01

    By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

  12. Angle-dependent rotation of calcite in elliptically polarized light

    Science.gov (United States)

    Herne, Catherine M.; Cartwright, Natalie A.; Cattani, Matthew T.; Tracy, Lucas A.

    2017-08-01

    Calcite crystals trapped in an elliptically polarized laser field exhibit intriguing rotational motion. In this paper, we show measurements of the angle-dependent motion, and discuss how the motion of birefringent calcite can be used to develop a reliable and efficient process for determining the polarization ellipticity and orientation of a laser mode. The crystals experience torque in two ways: from the transfer of spin angular momentum (SAM) from the circular polarization component of the light, and from a torque due to the linear polarization component of the light that acts to align the optic axis of the crystal with the polarization axis of the light. These torques alternatingly compete with and amplify each other, creating an oscillating rotational crystal velocity. We model the behavior as a rigid body in an angle-dependent torque. We experimentally demonstrate the dependence of the rotational velocity on the angular orientation of the crystal by placing the crystals in a sample solution in our trapping region, and observing their behavior under different polarization modes. Measurements are made by acquiring information simultaneously from a quadrant photodiode collecting the driving light after it passes through the sample region, and by imaging the crystal motion onto a camera. We finish by illustrating how to use this model to predict the ellipticity of a laser mode from rotational motion of birefringent crystals.

  13. Manipulation and electron-oscillation-measurement of laser accelerated electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kotaki, H; Hayashi, Y; Kawase, K; Mori, M; Kando, M; Homma, T; Koga, J K; Daido, H; Bulanov, S V, E-mail: kotaki.hideyuki@jaea.go.jp [Advanced Photon Research Center, Japan Atomic Energy Agency, 8-1-7, Umemidai, Kizugawa, Kyoto (Japan)

    2011-01-15

    Monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A stable electron beam is generated in the self-injection scheme by using a nitrogen gas jet target. We found the profile of the electron beam was manipulated by rotating the laser polarization. The electron beam is in the first bucket of the wake wave. In the energy space, transverse oscillation is observed when the laser pulse has S-polarization. The direction of the electron beam is controlled by the gas jet position.

  14. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  15. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented

  16. Polar low monitoring

    Science.gov (United States)

    Bobylev, Leonid; Zabolotskikh, Elizaveta; Mitnik, Leonid

    2010-05-01

    Polar lows are intense mesoscale atmospheric low pressure weather systems, developing poleward of the main baroclinic zone and associated with high surface wind speeds. Small size and short lifetime, sparse in-situ observations in the regions of their development complicate polar low study. Our knowledge of polar lows and mesocyclones has come almost entirely during the period of satellite remote sensing since, by virtue of their small horizontal scale, it was rarely possible to analyse these lows on conventional weather charts using only the data from the synoptic observing network. However, the effects of intense polar lows have been felt by coastal communities and seafarers since the earliest times. These weather systems are thought to be responsible for the loss of many small vessels over the centuries, although the nature of the storms was not understood and their arrival could not be predicted. The actuality of the polar low research is stipulated by their high destructive power: they are a threat to such businesses as oil and gas exploration, fisheries and shipping. They could worsen because of global warming: a shrinking of sea ice around the North Pole, which thawed to its record minimum in the summer of 2007, is likely to give rise to more powerful storms that form only over open water and can cause hurricane-strength winds. Therefore, study of polar lows, their timely detection, tracking and forecasting represents a challenge for today meteorology. Satellite passive microwave data, starting from Special Sensor Microwave Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP) satellite, remain invaluable source of regularly available remotely sensed data to study polar lows. The sounding in this spectral range has several advantages in comparison with observations in visible and infrared ranges and Synthetic Aperture Radar (SAR) data: independence on day time and clouds, regularity and high temporal resolution in Polar Regions. Satellite

  17. 20 nJ 200 fs all-fiber highly chirped dissipative soliton oscillator.

    Science.gov (United States)

    Kharenko, D S; Podivilov, E V; Apolonski, A A; Babin, S A

    2012-10-01

    The dissipative solitons (DS) generated in fiber oscillators with mode-locking mechanism based on nonlinear polarization evolution in a single-mode fiber exhibit stability and energy limits at the cavity lengthening. We demonstrate an alternative approach that enables us to increase the cavity length of the DS oscillator up to 30 m, namely, by the use of a long section of polarization-maintaining (PM) fiber in an all-fiber cavity configuration. We have also identified the next limit of energy scaling related to the onset of Raman conversion of the DS spectrum. The maximum energy of the stable highly chirped DS realized with a 5.5 μm core PM fiber, amounts to ~20 nJ in ~200 fs pulses after a grating compressor. As a next step, energy scaling by means of a fiber core enlargement is discussed.

  18. Active locking and entanglement in type II optical parametric oscillators

    Science.gov (United States)

    Ruiz-Rivas, Joaquín; de Valcárcel, Germán J.; Navarrete-Benlloch, Carlos

    2018-02-01

    Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

  19. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

    The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

  20. The Bochum Polarized Target

    International Nuclear Information System (INIS)

    Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

    2001-01-01

    The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

  1. In-line Fiber Polarizer

    OpenAIRE

    Perumalsamy, Priya

    1998-01-01

    Polarizers and polarization devices are important components in fiber optic communication and sensor systems. There is a growing need for efficient low loss components that are compatible with optical fibers. An all fiber in-line polarizer is a more desirable alternative that could be placed at appropriate intervals along communication links. An in-line fiber polarizer was fabricated and tested. The in-line fiber polarizer operates by coupling optical energy propagatin...

  2. Oscillations

    Directory of Open Access Journals (Sweden)

    Qinghua Wu

    2015-01-01

    equivalent to the GMRES method proposed by Olver (2009. Moreover, the simpler GMRES does not require upper Hessenberg matrix factorization, which leads to much simpler program and requires less work. Numerical experiments are conducted to illustrate the performance of the new method and show that in some cases the simpler GMRES method could achieve higher accuracy than GMRES.

  3. Separation control with fluidic oscillators in water

    Science.gov (United States)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2017-08-01

    The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

  4. Political Competition and Polarization

    DEFF Research Database (Denmark)

    Schultz, Christian

    This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signa...... for costs before an upcoming election. It is shown that the more polarized the political parties the more distorted the incumbent's policy choice.......This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signal...

  5. Physics of polarized targets

    CERN Document Server

    Niinikoski, Tapio

    2014-01-01

    For developing, building and operating solid polarized targets we need to understand several fields of physics that have seen sub stantial advances during the last 50 years. W e shall briefly review a selection of those that are important today. These are: 1) quantum statistical methods to describe saturation and relaxation in magnetic resonance; 2) equal spin temperature model for dy namic nuclear polarization; 3 ) weak saturation during NMR polarization measurement; 4 ) refrigeration using the quantum fluid properties of helium isotopes. These, combined with superconducting magnet technologies, permit today to reach nearly complete pola rization of almost any nuclear spins. Targets can be operated in frozen spin mode in rather low and inhomogeneous field of any orientation, and in DNP mode in beams of high intensity. Beyond such experiments of nuclear and particle physics, applications a re also emerging in macromolecular chemistry and in magnetic resonance imaging. This talk is a tribute to Michel Borghini...

  6. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    The organizational science literature on motivation has for long been polarized into two main positions; the organizational economic position focusing on extrinsic motivation and the organizational behavior position emphasizing intrinsic motivation. With the rise of the knowledge economy...... and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...... between the two as well as different types of motivations filling in the gap between the two polar types, is urgently needed in the organizational science literature. By drawing on the research on intrinsic and extrinsic motivation conducted in social psychology and combining this with contributions from...

  7. Polarized source upgrading

    International Nuclear Information System (INIS)

    Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

    1985-01-01

    The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

  8. A lunar polar expedition

    Science.gov (United States)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-09-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  9. Dark Polar Dunes

    Science.gov (United States)

    2005-01-01

    20 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, acquired during northern summer in December 2004, shows dark, windblown sand dunes in the north polar region of Mars. A vast sea of sand dunes nearly surrounds the north polar cap. These landforms are located near 80.3oN, 144.1oW. Light-toned features in the image are exposures of the substrate that underlies the dune field. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  10. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  11. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  12. Internal polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Kinney, E.R.; Coulter, K.; Gilman, R.; Holt, R.J.; Kowalczyk, R.S.; Napolitano, J.; Potterveld, D.H.; Young, L. (Argonne National Lab., IL (USA)); Mishnev, S.I.; Nikolenko, D.M.; Popov, S.G.; Rachek, I.A.; Temnykh, A.B.; Toporkov, D.K.; Tsentalovich, E.P.; Wojtsekhowski, B.B. (AN SSSR, Novosibirsk (USSR). Inst. Yadernoj Fiziki)

    1989-01-01

    Internal polarized targets offer a number of advantages over external targets. After a brief review of the basic motivation and principles behind internal polarized targets, the technical aspects of the atomic storage cell will be discussed in particular. Sources of depolarization and the means by which their effects can be ameliorated will be described, especially depolarization by the intense magnetic fields arising from the circulating particle beam. The experience of the Argonne Novosibirsk collaboration with the use of a storage cell in a 2 GeV electron storage ring will be the focus of this technical discussion. 17 refs., 11 figs.

  13. AGS polarized H- source

    International Nuclear Information System (INIS)

    Kponou, A.; Alessi, J.G.; Sluyters, T.

    1985-01-01

    The AGS polarized H - source is now operational. During a month-long experimental physics run in July 1984, pulses equivalent to 15 μA x 300 μs (approx. 3 x 10 10 protons) were injected into the RFQ preaccelerator. Beam polarization, measured at 200 MeV, was approx. 75%. After the run, a program to increase the H - yield of the source was begun and significant progress has been made. The H - current is now frequently 20 to 30 μA. A description of the source and some details of our operating experience are given. We also briefly describe the improvement program

  14. Polarization Characteristics Inferred From the Radio Receiver Instrument on the Enhanced Polar Outflow Probe

    Science.gov (United States)

    Danskin, Donald W.; Hussey, Glenn C.; Gillies, Robert G.; James, H. Gordon; Fairbairn, David T.; Yau, Andrew W.

    2018-02-01

    The Radio Receiver Instrument (RRI) on the CAScade, Smallsat, and Ionospheric Polar Explorer/enhanced Polar Outflow Probe (CASSIOPE/e-POP) satellite was used to receive continuous wave and binary phase shift keyed transmissions from a high-frequency transmitter located in Ottawa, ON, Canada during April 2016 to investigate how the ionosphere affects the polarization characteristics of transionospheric high-frequency radio waves. The spacecraft orientation was continuously slewed to maintain the dipole orientation in a plane perpendicular to the direction toward the transmitter, enabling the first in situ planar polarization determination for continuous wave and binary phase shift keyed modulated radio waves from space at times when the wave frequency is at least 1.58 times the plasma frequency. The Stokes parameters and polarization characteristics were derived from the measured data and interpreted using an existing ray tracing model. For the southern part of the passes, the power was observed to oscillate between the two dipoles of RRI, which was attributed to Faraday rotation of the radio waves. For the first time, a reversal in the rate of change of orientation angle was observed where the minimum in modeled Faraday rotation occurred. The reversal point was poleward of the point of closest approach between the satellite and transmitter; this was explained by the variations of total electron content and component of magnetic field along the direction of propagation. The received signals show both quasi-longitudinal (QL) and quasi-transverse characteristics. South of the transmitter the QL regime is dominant. Around the reversal point, a combination of QL and quasi-transverse nature was observed.

  15. Clusters in nonsmooth oscillator networks

    Science.gov (United States)

    Nicks, Rachel; Chambon, Lucie; Coombes, Stephen

    2018-03-01

    For coupled oscillator networks with Laplacian coupling, the master stability function (MSF) has proven a particularly powerful tool for assessing the stability of the synchronous state. Using tools from group theory, this approach has recently been extended to treat more general cluster states. However, the MSF and its generalizations require the determination of a set of Floquet multipliers from variational equations obtained by linearization around a periodic orbit. Since closed form solutions for periodic orbits are invariably hard to come by, the framework is often explored using numerical techniques. Here, we show that further insight into network dynamics can be obtained by focusing on piecewise linear (PWL) oscillator models. Not only do these allow for the explicit construction of periodic orbits, their variational analysis can also be explicitly performed. The price for adopting such nonsmooth systems is that many of the notions from smooth dynamical systems, and in particular linear stability, need to be modified to take into account possible jumps in the components of Jacobians. This is naturally accommodated with the use of saltation matrices. By augmenting the variational approach for studying smooth dynamical systems with such matrices we show that, for a wide variety of networks that have been used as models of biological systems, cluster states can be explicitly investigated. By way of illustration, we analyze an integrate-and-fire network model with event-driven synaptic coupling as well as a diffusively coupled network built from planar PWL nodes, including a reduction of the popular Morris-Lecar neuron model. We use these examples to emphasize that the stability of network cluster states can depend as much on the choice of single node dynamics as it does on the form of network structural connectivity. Importantly, the procedure that we present here, for understanding cluster synchronization in networks, is valid for a wide variety of systems in

  16. Harmonic oscillator and nuclear pseudospin

    International Nuclear Information System (INIS)

    Lisboa, Ronai; Malheiro, Manuel; Castro, Antonio S. de; Alberto, Pedro; Fiolhais, M.

    2004-01-01

    A generalized relativistic harmonic oscillator for spin 1/2 particles is studied. The Dirac Hamiltonians contains a scalar S and a vector V quadratic potentials in the radial coordinate, as well as a tensor potential U, linear in r. Setting either Σ=S+V or Δ=V - S to zero, analytical solutions for bound states are found. The eigenenergies and their nonrelativistic limits are present and particular cases are discussed, especially the case Σ=0, for which pseudospin symmetry is exact. (author)

  17. Wave Physics Oscillations - Solitons - Chaos

    CERN Document Server

    Nettel, Stephen

    2009-01-01

    This textbook is intended for those second year undergraduates in science and engineering who will later need an understanding of electromagnetic theory and quantum mechanics. The classical physics of oscillations and waves is developed at a more advanced level than has been customary for the second year, providing a basis for the quantum mechanics that follows. In this new edition the Green's function is explained, reinforcing the integration of quantum mechanics with classical physics. The text may also form the basis of an "introduction to theoretical physics" for physics majors. The concluding chapters give special attention to topics in current wave physics: nonlinear waves, solitons, and chaotic behavior.

  18. Pair creation and plasma oscillations

    International Nuclear Information System (INIS)

    We describe aspects of particle creation in strong fields using a quantum kinetic equation with a relaxation-time approximation to the collision term. The strong electric background field is determined by solving Maxwell's equation in tandem with the Vlasov equation. Plasma oscillations appear as a result of feedback between the background field and the field generated by the particles produced. The plasma frequency depends on the strength of the initial background fields and the collision frequency, and is sensitive to the necessary momentum-dependence of dressed-parton masses

  19. Making space for harmonic oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Michelotti, Leo; /Fermilab

    2004-11-01

    If we restrict the number of harmonic oscillator energy eigenstates to some finite value, N, then the discrete spectrum of the corresponding position operator comprise the roots of the Hermite polynomial H{sub N+1}. Its range is just large enough to accommodate classical motion at high energy. A negative energy term must be added to the Hamiltonian which affects only the last eigenstate, |N>, suggesting it is concentrated at the extrema of this finite ''space''. Calculations support a conjecture that, in the limit of large N, the global distribution of points approaches the differential form for classical action.

  20. Relaxation Oscillation and Canard Explosion

    Science.gov (United States)

    Krupa, M.; Szmolyan, P.

    2001-08-01

    We give a geometric analysis of relaxation oscillations and canard cycles in singularly perturbed planar vector fields. The transition from small Hopf-type cycles to large relaxation cycles, which occurs in an exponentially thin parameter interval, is described as a perturbation of a family of singular cycles. The results are obtained by means of two blow-up transformations combined with standard tools of dynamical systems theory. The efficient use of various charts is emphasized. The results are applied to the van der Pol equation.

  1. The physics of polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    This course is intended to give a description of the basic physical concepts which underlie the study and the interpretation of polarization phenomena. Apart from a brief historical introduction (Sect. 1), the course is organized in three parts. A first part (Sects. 2 - 6) covers the most relevant facts about the polarization phenomena that are typically encountered in laboratory applications and in everyday life. In Sect. 2, the modern description of polarization in terms of the Stokes parameters is recalled, whereas Sect. 3 is devoted to introduce the basic tools of laboratory polarimetry, such as the Jones calculus and the Mueller matrices. The polarization phenomena which are met in the reflection and refraction of a beam of radiation at the separation surface between two dielectrics, or between a dielectric and a metal, are recalled in Sect. 4. Finally, Sect. 5 gives an introduction to the phenomena of dichroism and of anomalous dispersion and Sect. 6 summarizes the polarization phenomena that are commonly encountered in everyday life. The second part of this course (Sects. 7-14) deals with the description, within the formalism of classical physics, of the spectro-polarimetric properties of the radiation emitted by accelerated charges. Such properties are derived by taking as starting point the Liénard and Wiechert equations that are recalled and discussed in Sect. 7 both in the general case and in the non-relativistic approximation. The results are developed to find the percentage polarization, the radiation diagram, the cross-section and the spectral characteristics of the radiation emitted in different phenomena particularly relevant from the astrophysical point of view. The emission of a linear antenna is derived in Sect. 8. The other Sections are devoted to Thomson scattering (Sect. 9), Rayleigh scattering (Sect. 10), Mie scattering (Sect. 11), bremsstrahlung radiation (Sect. 12), cyclotron radiation (Sect. 13), and synchrotron radiation (Sect. 14

  2. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  3. Phase noise and frequency stability in oscillators

    CERN Document Server

    Rubiola, Enrico

    2009-01-01

    Presenting a comprehensive account of oscillator phase noise and frequency stability, this practical text is both mathematically rigorous and accessible. An in-depth treatment of the noise mechanism is given, describing the oscillator as a physical system, and showing that simple general laws govern the stability of a large variety of oscillators differing in technology and frequency range. Inevitably, special attention is given to amplifiers, resonators, delay lines, feedback, and flicker (1/f) noise. The reverse engineering of oscillators based on phase-noise spectra is also covered, and end-of-chapter exercises are given. Uniquely, numerous practical examples are presented, including case studies taken from laboratory prototypes and commercial oscillators, which allow the oscillator internal design to be understood by analyzing its phase-noise spectrum. Based on tutorials given by the author at the Jet Propulsion Laboratory, international IEEE meetings, and in industry, this is a useful reference for acade...

  4. Driven, autoresonant three-oscillator interactions

    International Nuclear Information System (INIS)

    Yaakobi, O.; Friedland, L.; Henis, Z.

    2007-01-01

    An efficient control scheme of resonant three-oscillator interactions using an external chirped frequency drive is suggested. The approach is based on formation of a double phase-locked (autoresonant) state in the system, as the driving oscillation passes linear resonance with one of the interacting oscillators. When doubly phase locked, the amplitudes of the oscillators increase with time in proportion to the driving frequency deviation from the linear resonance. The stability of this phase-locked state and the effects of dissipation and of the initial three-oscillator frequency mismatch on the autoresonance are analyzed. The associated autoresonance threshold phenomenon in the driving amplitude is also discussed. In contrast to other nonlinear systems, driven, autoresonant three-oscillator excitations are independent of the sign of the driving frequency chirp rate

  5. Arctic amplification: does it impact the polar jet stream?

    Directory of Open Access Journals (Sweden)

    Valentin P. Meleshko

    2016-10-01

    Full Text Available It has been hypothesised that the Arctic amplification of temperature changes causes a decrease in the northward temperature gradient in the troposphere, thereby enhancing the oscillation of planetary waves leading to extreme weather in mid-latitudes. To test this hypothesis, we study the response of the atmosphere to Arctic amplification for a projected summer sea-ice-free period using an atmospheric model with prescribed surface boundary conditions from a state-of-the-art Earth system model. Besides a standard global warming simulation, we also conducted a sensitivity experiment with sea ice and sea surface temperature anomalies in the Arctic. We show that when global climate warms, enhancement of the northward heat transport provides the major contribution to decrease the northward temperature gradient in the polar troposphere in cold seasons, causing more oscillation of the planetary waves. However, while Arctic amplification significantly enhances near-surface air temperature in the polar region, it is not large enough to invoke an increased oscillation of the planetary waves.

  6. Damping elastic oscillations of digging mechanism

    Science.gov (United States)

    Kuznetsov, N. K.; Makhno, D. E.; Iov, I. A.

    2017-10-01

    The article studies methods for reducing dynamic loading and elastic oscillations of excavator buckets using dampers. The authors suggest a structural scheme for damping bucket oscillations using a damping device installed in a running gear of the traction cable. The results of numerical efficiency simulation are presented. The article shows that the system helps to reduce intensity of elastic oscillations and a transition period in acceleration and deceleration modes.

  7. Oscillations of neutral B mesons systems

    CERN Document Server

    Boucrot, J.

    1999-01-01

    The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the $\\bd$ meson oscillation frequency is $\\dmd = 0.471 \\pm 0.016 \\ps$ and the lower limit on the $\\bs$ oscillation frequency is

  8. Synchronization of weakly coupled canard oscillators

    OpenAIRE

    Köksal Ersöz, Elif; Desroches, Mathieu; Krupa, Martin

    2017-01-01

    International audience; Synchronization has been studied extensively in the context of weakly coupled oscillators using the so-called phase response curve (PRC) which measures how a change of the phase of an oscillator is affected by a small perturbation. This approach was based upon the work of Malkin, and it has been extended to relaxation oscillators. Namely, synchronization conditions were established under the weak coupling assumption, leading to a criterion for the existence of synchron...

  9. Lobbying and political polarization

    OpenAIRE

    Ursprung, Heinrich W.

    2002-01-01

    Standard spatial models of political competition give rise to equilibria in which the competing political parties or candidates converge to a common position. In this paper I show how political polarization can be generated in models that focus on the nexus between pre-election interest group lobbying and electoral competition.

  10. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  11. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  12. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  13. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  14. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  15. Cardiogenic oscillation induced ventilator autotriggering

    Directory of Open Access Journals (Sweden)

    Narender Kaloria

    2015-01-01

    Full Text Available Cardiogenic oscillation during mechanical ventilation can auto-trigger the ventilator resembling patient initiated breadth. This gives a false sense of intact respiratory drive and determination brain death, even if other tests are positive, is not appropriate in such a situation. It will prolong the ICU stay and confound the brain-death determination. In this case report, we describe a 35 year old man who was brought to the hospital after many hours of critical delay following multiple gun shot injuries. The patient suffered a cardiac arrest while on the way from another hospital. After an emergency laparotomy, patient was shifted to Intensive Care Unit (ICU with Glasgow Coma Scale (GCS score of E1VTM1 and was mechanically ventilated. Despite absence of brainstem reflexes, the ventilator continued to be triggered on continuous positive airway pressure (CPAP mode and the patient maintained normal oxygen saturation and acceptable levels of carbon dioxide. An apnoea test confirmed absent respiratory drive. Ventilatory waveform graph analysis, revealed cardiogenic oscillation as the cause for autotrigerring.

  16. Investigation of Transverse Oscillation Method

    DEFF Research Database (Denmark)

    Udesen, Jesper; Jensen, Jørgen Arendt

    2006-01-01

    Conventional ultrasound scanners can only display the axial component of the blood velocity vector, which is a significant limitation when vessels nearly parallel to the skin surface are scanned. The transverse oscillation method (TO) overcomes this limitation by introducing a transverse oscillat......Conventional ultrasound scanners can only display the axial component of the blood velocity vector, which is a significant limitation when vessels nearly parallel to the skin surface are scanned. The transverse oscillation method (TO) overcomes this limitation by introducing a transverse...... II. A virtual linear array transducer with center frequency 7 MHz and 128 active elements is created, and a virtual blood vessel of radius 6.4 mm is simulated. The performance of the TO method is found around an initial point in the parameter space. The parameters varied are: flow angle, transmit...... focus depth, receive apodization, pulse length, transverse wave length, number of emissions, signal to noise ratio, and type of echo canceling filter used. Using the experimental scanner RASMUS, the performance of the TO method is evaluated. An experimental flowrig is used to create laminar parabolic...

  17. Waves and oscillations in nature an introduction

    CERN Document Server

    Narayanan, A Satya

    2015-01-01

    Waves and oscillations are found in large scales (galactic) and microscopic scales (neutrino) in nature. Their dynamics and behavior heavily depend on the type of medium through which they propagate.Waves and Oscillations in Nature: An Introduction clearly elucidates the dynamics and behavior of waves and oscillations in various mediums. It presents different types of waves and oscillations that can be observed and studied from macroscopic to microscopic scales. The book provides a thorough introduction for researchers and graduate students in assorted areas of physics, such as fluid dynamics,

  18. High Reliability Oscillators for Terahertz Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Terahertz sources based on lower frequency oscillators and amplifiers plus a chain of frequency multipliers are the workhorse technology for NASA's terahertz...

  19. Introduction to classical and quantum harmonic oscillators

    CERN Document Server

    Bloch, Sylvan C

    2013-01-01

    From conch shells to lasers . harmonic oscillators, the timeless scientific phenomenon As intriguing to Galileo as they are to scientists today, harmonic oscillators have provided a simple and compelling paradigm for understanding the complexities that underlie some of nature's and mankind's most fascinating creations. From early string and wind instruments fashioned from bows and seashells to the intense precision of lasers, harmonic oscillators have existed in various forms, as objects of beauty and scientific use. And harmonic oscillation has endured as one of science's most fascinating con

  20. Strengthening and damping of synchrotron oscillations

    International Nuclear Information System (INIS)

    Taratin, A.M.

    2001-01-01

    Resonance strengthening and damping of synchrotron oscillations of collider bunch halo particles was studied by simulation. It was shown that the strengthening of particle synchrotron oscillations can be highly efficient with using a resonance pulse sequence. The resonance damping of particle synchrotron oscillations is only possible when the inverse population of the accelerated bunch halo is realized. Resonance method of synchrotron oscillation strengthening can be used for the extraction of beam halo particles with a bent crystal to improve the background conditions for colliding beam experiments and to fulfill simultaneously some fixed target experiments

  1. Scleronomic holonomic constraints and conservative nonlinear oscillators

    International Nuclear Information System (INIS)

    Munoz, R; Gonzalez-Garcia, G; Izquierdo-De La Cruz, E Izquierdo-De La; Fernandez-Anaya, G

    2011-01-01

    A bead sliding, under the sole influence of its own weight, on a rigid wire shaped in the fashion of a plane curve, will describe (generally anharmonic) oscillations around a local minimum. For given shapes, the bead will behave as a harmonic oscillator in the whole range, such as an unforced, undamped, Duffing oscillator, etc. We also present cases in which the effective potential acting on the bead is not analytical around a minimum. The small oscillation approximation cannot be applied to such pathological cases. Nonetheless, these latter instances are studied with other standard techniques.

  2. Scleronomic holonomic constraints and conservative nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, R; Gonzalez-Garcia, G; Izquierdo-De La Cruz, E Izquierdo-De La [Universidad Autonoma de la Ciudad de Mexico, Centro Historico, Fray Servando Teresa de Mier 92, Col Centro, Del Cuauhtemoc, Mexico DF, CP 06080 (Mexico); Fernandez-Anaya, G, E-mail: rodrigo.munoz@uacm.edu.mx, E-mail: gggharper@gmail.com, E-mail: erickidc@gmail.com, E-mail: guillermo.fernandez@uia.mx [Universidad Iberoamericana, Departamento de Fisica y Matematicas, Prolongacon Paseo de de la Reforma 880, Col Lomas de Santa Fe, Del Alvaro Obregn, Mexico DF, CP 01219 (Mexico)

    2011-05-15

    A bead sliding, under the sole influence of its own weight, on a rigid wire shaped in the fashion of a plane curve, will describe (generally anharmonic) oscillations around a local minimum. For given shapes, the bead will behave as a harmonic oscillator in the whole range, such as an unforced, undamped, Duffing oscillator, etc. We also present cases in which the effective potential acting on the bead is not analytical around a minimum. The small oscillation approximation cannot be applied to such pathological cases. Nonetheless, these latter instances are studied with other standard techniques.

  3. Reentrant transition in coupled noisy oscillators.

    Science.gov (United States)

    Kobayashi, Yasuaki; Kori, Hiroshi

    2015-01-01

    We report on a synchronization-breaking instability observed in a noisy oscillator unidirectionally coupled to a pacemaker. Using a phase oscillator model, we find that, as the coupling strength is increased, the noisy oscillator lags behind the pacemaker more frequently and the phase slip rate increases, which may not be observed in averaged phase models such as the Kuramoto model. Investigation of the corresponding Fokker-Planck equation enables us to obtain the reentrant transition line between the synchronized state and the phase slip state. We verify our theory using the Brusselator model, suggesting that this reentrant transition can be found in a wide range of limit cycle oscillators.

  4. Polarization Charge Density in Strained Graphene

    Science.gov (United States)

    Wilson, Noah

    Graphene, the world's first truly two-dimensional material, is unique for having an electronic structure described by an effective Lorentz invariant theory. One important consequence is that the ratio or Coulomb energy to kinetic energy is a constant, depending only on conditions within the lattice rather than on the average charge density as in a typical Galilean invariant material. Given this unusual property, a natural question would be how do phenomena, such as screening of a Coulomb impurity, happen in graphene? Moreover, how does the addition of uniaxial strain enhance or diminish this behavior? Here I discuss our work to calculate the charge density distribution in a lattice of strained graphene under the effect of an external Coulomb impurity. Graphene can have its band structure significantly altered by the application of uniaxial strain. Two cases are here explored: relatively weak strain at some finite chemical potential, and extreme strain with zero chemical potential. In the first system, the strain induces elliptic Dirac cones, engendering some inherent directionality to graphene's electronic properties that did not exist before. This anisotropy manifests itself in the polarization function, and so too in the screening charge density. A finite chemical potential in this case is necessary for any screening to take place in graphene since, without it, there are no electron states near the Fermi level to polarize. Both in the strained and unstrained case, decaying oscillations known as Friedel oscillations are observed. The result of strain is a multifaceted anisotropy of the charge distribution: the amplitude, frequency, and the position of the first peak in the oscillations are each varied depending on the direction one observes. In the second system, extreme strain in graphene leads to a merging of Dirac cones, yielding a transition to a new energy spectrum. This band structure is unusual in that it becomes quadratic along the direction of strain

  5. Neutron Multiplicity And Active Well Neutron Coincidence Verification Measurements Performed For March 2009 Semi-Annual DOE Inventory

    International Nuclear Information System (INIS)

    Dewberry, R.; Ayers, J.; Tietze, F.; Klapper, K.

    2010-01-01

    The Analytical Development (AD) Section field nuclear measurement group performed six 'best available technique' verification measurements to satisfy a DOE requirement instituted for the March 2009 semi-annual inventory. The requirement of (1) yielded the need for SRNL Research Operations Department Material Control and Accountability (MC and A) group to measure the Pu content of five items and the highly enrich uranium (HEU) content of two. No 14Q-qualified measurement equipment was available to satisfy the requirement. The AD field nuclear group has routinely performed the required Confirmatory Measurements for the semi-annual inventories for fifteen years using sodium iodide and high purity germanium (HpGe) γ-ray pulse height analysis nondestructive assay (NDA) instruments. With appropriate γ-ray acquisition modeling, the HpGe spectrometers can be used to perform verification-type quantitative assay for Pu-isotopics and HEU content. The AD nuclear NDA group is widely experienced with this type of measurement and reports content for these species in requested process control, MC and A booking, and holdup measurements assays Site-wide. However none of the AD HpGe γ-ray spectrometers have been 14Q-qualified, and the requirement of reference 1 specifically excluded a γ-ray PHA measurement from those it would accept for the required verification measurements. The requirement of reference 1 was a new requirement for which the Savannah River National Laboratory (SRNL) Research Operations Department (ROD) MC and A group was unprepared. The criteria for exemption from verification were: (1) isotope content below 50 grams; (2) intrinsically tamper indicating or TID sealed items which contain a Category IV quantity of material; (3) assembled components; and (4) laboratory samples. Therefore all (SRNL) Material Balance Area (MBA) items with greater than 50 grams total Pu or greater than 50 grams HEU were subject to a verification measurement. The pass/fail criteria of

  6. Dynamic Effects of the Earth's Rotation Caused by the Annual and Semi-Annual Cyclic Mass Redistribution of the Planet

    Directory of Open Access Journals (Sweden)

    M. Yu. Barkin

    2016-01-01

    Full Text Available The paper deals with development of the theory of perturbed rotational motion of a celestial body with variable geometry of the masses. Its main task is to study the impact of annual and semi-annual variations of the Earth's mass geometry (a component of its inertia tensor, as well as a component of its relative angular momentum, on the movement of the Earth's poles and its axial rotation. The body is considered to be a free (isolated, and the problem formulation corresponds to the classical Liouville problem on rotation of a variable body. Euler conical movement of the axially symmetric body with an arbitrary constant half-angle  is assumed as the unperturbed motion. In the classical theory of the Earth's rotation this angle is usually assumed to be zero.In the last 20 years, accuracy to determine the Earth rotation parameters owing to using methods of space geodesy and method of Very Long Baseline Interferometry (VLBI has increased by about three orders of magnitude and has made about  i.e., in angle measure it is about 10 - 20 arc-microseconds. According to experts, the theory of the Earth's rotation with such precision is not created yet. The paper is focused just on the new dynamic studies of the Earth rotation at a higher level of accuracy than has been done in previous studies, using a new approach to the problem, based on the new forms of the equations of motion (in the Andoyer variables and the analytical methods of perturbation theory (small parameter method.The problem of perturbed rotational motion with variable geometry and variable mass relative angular momentum in the first approximation is solved in Andoyer variables and projections of the angular velocity of the planet rotation. The analytical solution allows us to run applications to study dynamic effects from above factors for various bodies in the solar system, including the Earth. The solution allowed us to obtain the following parameters of the fundamental effects in the

  7. Endogenous oscillations of electric potential difference in the cambial region of the pine stem. II. Possible involvement of the oscillations in xylogenesis

    Directory of Open Access Journals (Sweden)

    Wojciech Kurek

    2014-01-01

    Full Text Available Direct and indirect interrelations between xylogenic processes and the endogenous electric potential difference (PD oscillations generated in the cambial region of isolated tissue blocks from pine trunks were investigated. The frequency of transient PD changes varied during the season and displayed three minima which were concurrent with periods of initiation and termination of cambial activity and with the time of transition from early- to late-wood production. The oscillations were damped by TIBA - an inhibitor of polar auxin transport and stimulated by IAA, but only when the hormone was supplied to the apical end of the tissue block. This suggests that the polar transport of auxin may be involved in generation of the transient PD changes. Results of 2-channel recordings in one tissue block suggest that a part of the recorded oscillations (10-25 % exhibit coordination in space and time: a wave-like pattern along the trunk axis is created by PD changes. The pattern might be a physical carrier of information coordinating processes of growth and differentiation in distant parts of the tree.

  8. Characteristics of volume polarization holography with linear polarization light

    Science.gov (United States)

    Zang, Jinliang; Wu, An'an; Liu, Ying; Wang, Jue; Lin, Xiao; Tan, Xiaodi; Shimura, Tsutomu; Kuroda, Kazuo

    2015-10-01

    Volume polarization holographic recording in phenanthrenequinone-doped poly(methyl methacrylate) (PQ-PMMA) photopolymer with linear polarized light is obtained. The characteristics of the volume polarization hologram are experimentally investigated. It is found that beyond the paraxial approximation the polarization states of the holographic reconstruction light are generally different from the signal light. Based on vector wave theoretical analyses and material properties, the special exposure condition for correctly holographic reconstruction is obtained and experimentally demonstrated.

  9. Oscillating shells and oscillating balls in AdS

    Science.gov (United States)

    Banerjee, Avik; Kundu, Arnab; Roy, Pratik; Virmani, Amitabh

    2017-07-01

    It has recently been reported that certain thin timelike shells undergo oscillatory motion in AdS. In this paper, we compute two-point function of a probe field in the geodesic approximation in such an oscillating shell background. We confirm that the two-point function exhibits an oscillatory behaviour following the motion of the shell. We show that similar oscillatory dynamics is possible when the perfect fluid on the shell has a polytropic equation of state. Moreover, we show that certain ball like configurations in AdS also exhibit oscillatory motion and comment on how such a solution can be smoothly matched to an appropriate exterior solution. We also demonstrate that the weak energy condition is satisfied for these oscillatory configurations.

  10. Oscillations of Difference Equations with Several Oscillating Coefficients

    Directory of Open Access Journals (Sweden)

    L. Berezansky

    2014-01-01

    Full Text Available We study the oscillatory behavior of the solutions of the difference equation Δx(n+∑i=1mpi(nx(τi(n=0,n∈N0[∇xn-∑i=1mpinxσin=0, n∈N] where (pi(n, 1≤i≤m are real sequences with oscillating terms, τi(n[σi(n], 1≤i≤m are general retarded (advanced arguments, and Δ[∇] denotes the forward (backward difference operator Δx(n=x(n+1-x(n[∇x(n=x(n-x(n-1]. Examples illustrating the results are also given.

  11. A coupled-oscillator model of olfactory bulb gamma oscillations.

    Directory of Open Access Journals (Sweden)

    Guoshi Li

    2017-11-01

    Full Text Available The olfactory bulb transforms not only the information content of the primary sensory representation, but also its underlying coding metric. High-variance, slow-timescale primary odor representations are transformed by bulbar circuitry into secondary representations based on principal neuron spike patterns that are tightly regulated in time. This emergent fast timescale for signaling is reflected in gamma-band local field potentials, presumably serving to efficiently integrate olfactory sensory information into the temporally regulated information networks of the central nervous system. To understand this transformation and its integration with interareal coordination mechanisms requires that we understand its fundamental dynamical principles. Using a biophysically explicit, multiscale model of olfactory bulb circuitry, we here demonstrate that an inhibition-coupled intrinsic oscillator framework, pyramidal resonance interneuron network gamma (PRING, best captures the diversity of physiological properties exhibited by the olfactory bulb. Most importantly, these properties include global zero-phase synchronization in the gamma band, the phase-restriction of informative spikes in principal neurons with respect to this common clock, and the robustness of this synchronous oscillatory regime to multiple challenging conditions observed in the biological system. These conditions include substantial heterogeneities in afferent activation levels and excitatory synaptic weights, high levels of uncorrelated background activity among principal neurons, and spike frequencies in both principal neurons and interneurons that are irregular in time and much lower than the gamma frequency. This coupled cellular oscillator architecture permits stable and replicable ensemble responses to diverse sensory stimuli under various external conditions as well as to changes in network parameters arising from learning-dependent synaptic plasticity.

  12. Surface plasmon oscillations in a semi-bounded semiconductor plasma

    Science.gov (United States)

    M, SHAHMANSOURI; A, P. MISRA

    2018-02-01

    We study the dispersion properties of surface plasmon (SP) oscillations in a semi-bounded semiconductor plasma with the effects of the Coulomb exchange (CE) force associated with the spin polarization of electrons and holes as well as the effects of the Fermi degenerate pressure and the quantum Bohm potential. Starting from a quantum hydrodynamic model coupled to the Poisson equation, we derive the general dispersion relation for surface plasma waves. Previous results in this context are recovered. The dispersion properties of the surface waves are analyzed in some particular cases of interest and the relative influence of the quantum forces on these waves are also studied for a nano-sized GaAs semiconductor plasma. It is found that the CE effects significantly modify the behaviors of the SP waves. The present results are applicable to understand the propagation characteristics of surface waves in solid density plasmas.

  13. Correlation effect of Rabi oscillations of excitons in quantum dots

    International Nuclear Information System (INIS)

    Ishi-Hayase, J.; Akahane, K.; Yamamoto, Y.; Kujiraoka, M.; Ema, K.; Sasaki, M.

    2008-01-01

    We performed a transient four-wave mixing experiment on a strain-compensated InAs quantum dot (QD) ensemble over a wide range of excitation intensities. Under the resonant excitation of an exciton ground state, an extremely long dephasing time of 1 ns was found. By increasing the areas of the excitation pulses, Rabi oscillations of excitonic polarizations were clearly observed. The corresponding Rabi frequency is three orders of magnitude higher than the measured dephasing rate. For larger pulse areas, we found that the deviation of experimental data from two-level predictions became significant. The deviations cannot be explained by taking into account, as has been suggested in other research, excitation density-dependent dephasing or Hartree-Fock-type Coulomb interactions between excitons

  14. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  15. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  16. The State and Future of Mars Polar Science and Exploration

    Science.gov (United States)

    Clifford, Stephen M.; Crisp, David; Fisher, David A.; Herkenhoff, Ken E.; Smrekar, Suzanne E.; Thomas, Peter C.; Wynn-Williams, David D.; Zurek, Richard W.; Barnes, Jeffrey R.; Bills, Bruce G.

    2000-01-01

    As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of approx. 10(exp 6)sq km and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to he comparatively young-preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past approx. 10(exp 5)-10(exp 8) years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet-documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason-providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

  17. The State and Future of Mars Polar Science and Exploration

    Science.gov (United States)

    Clifford, S.M.; Crisp, D.; Fisher, D.A.; Herkenhoff, K. E.; Smrekar, S.E.; Thomas, P.C.; Wynn-Williams, D. D.; Zurek, R.W.; Barnes, J.R.; Bills, B.G.; Blake, E.W.; Calvin, W.M.; Cameron, J.M.; Carr, M.H.; Christensen, P.R.; Clark, B. C.; Clow, G.D.; Cutts, J.A.; Dahl-Jensen, D.; Durham, W.B.; Fanale, F.P.; Farmer, J.D.; Forget, F.; Gotto-Azuma, K.; Grard, R.; Haberle, R.M.; Harrison, W.; Harvey, R.; Howard, A.D.; Ingersoll, A.P.; James, P.B.; Kargel, J.S.; Kieffer, H.H.; Larsen, J.; Lepper, K.; Malin, M.C.; McCleese, D.J.; Murray, B.; Nye, J.F.; Paige, D.A.; Platt, S.R.; Plaut, J.J.; Reeh, N.; Rice, J.W.; Smith, D.E.; Stoker, C.R.; Tanaka, K.L.; Mosley-Thompson, E.; Thorsteinsson, T.; Wood, S.E.; Zent, A.; Zuber, M.T.; Zwally, H.J.

    2000-01-01

    As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of ???106 km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young - preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past ???105-108 years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet - documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason - providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding. ?? 2000 Academic Press.

  18. Geomagnetic polarity transitions

    Science.gov (United States)

    Merrill, Ronald T.; McFadden, Phillip L.

    1999-05-01

    The top of Earth's liquid outer core is nearly 2900 km beneath Earth's surface, so we will never be able to observe it directly. This hot, dense, molten iron-rich body is continuously in motion and is the source of Earth's magnetic field. One of the most dynamic manifestations at Earth's surface of this fluid body is, perhaps, a reversal of the geomagnetic field. Unfortunately, the most recent polarity transition occurred at about 780 ka, so we have never observed a transition directly. It seems that a polarity transition spans many human lifetimes, so no human will ever witness the phenomenon in its entirety. Thus we are left with the tantalizing prospect that paleomagnetic records of polarity transitions may betray some of the secrets of the deep Earth. Certainly, if there are systematics in the reversal process and they can be documented, then this will reveal substantial information about the nature of the lowermost mantle and of the outer core. Despite their slowness on a human timescale, polarity transitions occur almost instantaneously on a geological timescale. This rapidity, together with limitations in the paleomagnetic recording process, prohibits a comprehensive description of any reversal transition both now and into the foreseeable future, which limits the questions that may at this stage be sensibly asked. The natural model for the geomagnetic field is a set of spherical harmonic components, and we are not able to obtain a reliable model for even the first few harmonic terms during a transition. Nevertheless, it is possible, in principle, to make statements about the harmonic character of a geomagnetic polarity transition without having a rigorous spherical harmonic description of one. For example, harmonic descriptions of recent geomagnetic polarity transitions that are purely zonal can be ruled out (a zonal harmonic does not change along a line of latitude). Gleaning information about transitions has proven to be difficult, but it does seem

  19. Polarized electron beams at SLAC

    International Nuclear Information System (INIS)

    Moffeit, K.C.

    1992-11-01

    SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e+e- collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point

  20. Analytical polarization calculations beyond SLIM

    International Nuclear Information System (INIS)

    Barber, D.P.

    1989-01-01

    A comparison is made between the theories of Bell and Leinaas and of Derbenev and Kondratenko for the spin polarization in electron storage rings. A calculation of polarization in HERA using the program SMILE of Mane is presented

  1. Relativistic model-potential oscillator strengths and transition probabilities for 4fsup(n)6s-4fsup(n)6p transitions in Eu(II), Tb(II), and Ho(II) in J1j coupling

    International Nuclear Information System (INIS)

    Migdalek, J.

    1984-01-01

    The lowest 4fsup(n)6s-4fsup(n)6p transitions are studied for the Eu(II) (n=7), Tb(II) (n=9), and Ho(II) (n=11) spectra, where the J 1 J coupling is an acceptable approximation. The relativistic radial integrals, required to evaluate the oscillator strengths and transition probabilities, are calculated with the model-potential method, which includes also core-polarization effects. The similarities observed in oscillator strengths for transitions with given ΔJ but different J values are discussed and explained. The computed oscillator strengths are compared with those obtained with the Coulomb approximation and it is found that the latter are only 11-12% lower. The core polarization influence on oscillator strengths is also investigated and the 19-21% decrease in oscillator strengths due to this effect is predicted. This result may, however, be overestimated because of some deficiencies in our procedure. (author)

  2. On Determinants of Political Polarization

    OpenAIRE

    Grechyna, Daryna

    2015-01-01

    Political polarization has been shown to significantly influence a country's economic performance. However, little is known about the drivers of political polarization. In this article, we aim to identify the main determinants of political polarization using Bayesian Model Averaging to overcome the problem of model uncertainty. We find that the level of trust within a country and the degree of income inequality are the most robust determinants of political polarization.

  3. Studies on phase and squeezed states of quantum harmonic oscillators

    International Nuclear Information System (INIS)

    Ma, Xin.

    1989-01-01

    A fundamental quantum-mechanical problem on the phase of quantum harmonic oscillators, which has remained an enigma for more than sixty years since the first treatment by Dirac, is completely solved. Contrary to the common belief that no Hermitian phase operators can be found to describe the phase properties of a quantum harmonic oscillator, a well-defined Hermitian phase operator with an appropriate classical limit is constructed unambiguously. The approach is different in nature from those of many previous attempts which were more or less based on the idea of polar decomposition of the annihilation operator. The fundamental difference between the quantum phase and the classical phase in spite of their conceptual consistency is pointed out and explained. The eigenvalue spectrum and eigenstates of the phase operator are obtained. Some important properties of the phase operator and phase states are investigated. The rest of this research is devoted to the studies of multimode Gaussian squeezed states of quantum harmonic oscillators. Multimode squeeze operators and rotation operators are defined such that they have extremely similar algebraic properties as those of their single-mode counterparts. It is shown that the introduction of N-mode squeeze operators provides a convenient set of parameters to describe squeezing in multimode Gaussian squeezed states. The disentangling, normal ordering, and some other properties of N-mode squeeze operators are investigated. It is also shown that the time-evolution operator for a general N-mode quadratic Hamiltonian can be conveniently expressed as an operator product containing an N-mode squeeze operator, an N-mode rotation operator, and an N-mode displacement operator

  4. Development of an extended-burnup Mark B design. Second semiannual progress report, January-June 1979

    International Nuclear Information System (INIS)

    1979-11-01

    The immediate goal of the DOE/AP and L/B and W project is to extend the burnup of light water reactor fuel assemblies beyond present limits to 50,000 MWd/mtU batch average burnup. Fuel management plans and fuel designs are being directed to attain the increased burnup limits. Lead-test assemblies of extended-burnup designs will be manufactured, irradiated in a commercial pressurized water reactor, and examined to support extended-burnup fuel cycles. This report, covering the period from January through June 1979, is the second semiannual progress report for the program. Efforts have included analyses of extended-burnup fuel cycles, developed of both annular fuel pellet and segmented rod designs, and design of a nondestructive post-irradiation examination system

  5. F-Area Hazardous Waste Management Facility Semiannual Corrective Action Report, First and Second Quarter 1998, Volume I and II

    Energy Technology Data Exchange (ETDEWEB)

    Chase, J.

    1998-10-30

    This report addresses groundwater quality and monitoring data during first and second quarter 1998 for the F-Area Hazardous Waste management Facility (HWMF). The report fulfills the semiannual reporting requirements of Module III, Section D, of the 1995 Resource Conservation and Recovery Act (RCRA) Renewal Permit (South Carolina Hazardous and Mixed Waste Permit SC1-890-008-989), effective October 5, 1995 (hereafter referred to as the RCRA permit), and Section C of the Underground Injection Control Permit Application hereafter referred to as the Section C of the Underground Injection Control Permit Application (hereafter referred to as the UIC permit). The HWMF is described in the Introduction to Module III, Section C, of the RCRA permit.

  6. Demonstration of fuel resistant to pellet-cladding interaction. Phase 2. First semiannual report, January-June 1979

    International Nuclear Information System (INIS)

    Rosenbaum, H.S.

    1979-08-01

    This program has as its ultimate objective the demonstration of an advanced fuel design that is resistant to the failure mechanism known as fuel pellet-cladding interaction (PCI). Two fuel concepts are being developed for possible demonstration within this program: (a) Cu-barrier fuel and (b) Zr-liner fuel. These advanced fuels (known collectively as barrier fuels) have special fuel cladding designed to protect the Zircaloy cladding tube from the harmful effects of localized stress and reactive fission products during reactor service. This is the first semiannual progress report for Phase 2 of this program (January-June 1979). Progress in the irradiation testing of barrier fuel and of unfueled barrier cladding specimens is reported

  7. Semi-annual report of the Department of Energy, Office of Environmental Restoration and Waste Management, Quality Assessment Program

    International Nuclear Information System (INIS)

    Sanderson, C.G.; Scarpitta, S.C.

    1992-01-01

    This report presents the results from the analysis of the 36th set of environmental quality assessment samples (QAP 36) that were received on or before January 2, 1992. This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are complied with EML's results and are reported back to the participating contractors 30 days later. A summary of the reported results is available to the participants 3 days after the reporting deadline via a modem-telephone connection to the EML computer

  8. F-Area Hazardous Waste Management Facility Semiannual Corrective Action Report, First and Second Quarter 1998, Volume I and II

    International Nuclear Information System (INIS)

    Chase, J.

    1998-01-01

    This report addresses groundwater quality and monitoring data during first and second quarter 1998 for the F-Area Hazardous Waste management Facility (HWMF). The report fulfills the semiannual reporting requirements of Module III, Section D, of the 1995 Resource Conservation and Recovery Act (RCRA) Renewal Permit (South Carolina Hazardous and Mixed Waste Permit SC1-890-008-989), effective October 5, 1995 (hereafter referred to as the RCRA permit), and Section C of the Underground Injection Control Permit Application hereafter referred to as the Section C of the Underground Injection Control Permit Application (hereafter referred to as the UIC permit). The HWMF is described in the Introduction to Module III, Section C, of the RCRA permit

  9. Effectiveness of early preventive intervention with semiannual fluoride varnish application in toddlers living in high-risk areas

    DEFF Research Database (Denmark)

    Anderson, Maria; Dahllöf, Göran; Twetman, Svante

    2016-01-01

    a standardized oral health program once yearly between 1 and 3 years of age. The children in the test group received the same standard program supplemented with topical applications of fluoride varnish every 6 months. We compared the test group and the reference group for the prevalence and increment of caries...... lesions (ICDAS II 3-6), with a mean increment of 0.5 (SD 2.4) in the test group and 0.6 (SD 2.2) in the reference group. In conclusion, semiannual professional applications of fluoride varnish, as a supplement to a standard oral health program, failed to reduce caries development in toddlers from high...... socioeconomic standing in Stockholm participated in a cluster-randomized controlled field trial with two parallel arms. The children attended 23 dental clinics. Using the ICDAS II criteria, the examiners recorded caries at baseline and after 1 and 2 years. The children in the reference group received...

  10. Advanced Researech and Technology Development fossil energy materials program: Semiannual progress report for the period ending September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The objective of the ARandTD Fossil Energy Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. The ORNL Fossil Energy Materials Program Office compiles and issues this combined semiannual progress report from camera-ready copies submitted by each of the participating subcontractor organizations. This report of activities on the program is organized in accordance with a work breakdown structure in which projects are organized according to materials research thrust areas. These areas are (1) Structural Ceramics, (2) Alloy Development and Mechanical Properties, (3) Corrosion and Erosion of Alloys, and (4) Assessments and Technology Transfer. Individual projects are processed separately for the data bases.

  11. Title V Semi-Annual Emissions Report for Permit P100R1 July 1, 2011 - December 31, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Whetham, Walter [Los Alamos National Laboratory

    2012-03-15

    Reports of actual emissions from permitted sources in Section 2.0 shall be submitted on a 6 month basis. Reports shall not include emissions from insignificant activities. Emission estimates of criteria pollutants NOx, CO, SO2, PM and VOCs shall not include fugitive emissions. Emission estimates of HAPs shall include fugitive emissions. The reports shall include a comparison of actual emissions that occurred during the reporting period with the facility-wide allowable emission limits specified in Section 2.11 of this permit. The report required by Condition 4.1 shall be submitted within 90 days from the end of the reporting period. The semiannual report required by Condition 4.2 shall be submitted within 45 days from the end of the reporting period. The reporting periods are January 1st to June 30th and July 1st to December 31st. This condition is pursuant to 20.2.70.302.E.1 NMAC.

  12. Power plant waste heat utilization in aquaculture. Semi-annual report, No. 2, 1 November 1977--1 June 1978

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, C.R.; Godfriaux, B.L.

    1978-06-01

    The principal objective is to evaluate, at proof-of-concept scale, the potential of intensive aquaculture operations using power plant thermal discharges to enhance productivity. The field experiments involve the rearing of rainbow trout (Salmo gairdneri), channel catfish (Ictalurus punctatus) and American eel (Anguilla rostrata) for successive periods (semi-annual) in accordance with the temperature of the thermal effluents. Striped bass (Morone saxatilis) and the freshwater shrimp (Macrobrachium rosenbergii) are also being tested in smaller, laboratory size culture systems. The above mentioned species were selected because of their economic importance. They will be evaluated for food quality and marketability with the cooperation of potential commercial users. Aquaculture facilities were constructed at a steam electric generating plant for studies determining use for waste heat released into condenser cooling water. Growth rates, food conversion ratios, disease problems and mortality rates are being studied in the project. (Color illustrations reproduced in black and white) (Portions of this document are not fully legible)

  13. Semi-annual report of the Department of Energy, Office of Environmental Restoration and Waste Management, Quality Assessment Program

    International Nuclear Information System (INIS)

    Sanderson, C.G.; Klusek, C.S.

    1993-01-01

    This Quality Assessment Program (QAP) is designed to test the quality of the environmental measurements being reported to the Department of Energy by its contractors. Since 1976, real or synthetic environmental samples that have been prepared and thoroughly analyzed at the Environmental Measurements Laboratory (EML) have been distributed at first quarterly and then semi-annually to these contractors. Their results, which are returned to EML within 90 days, are compiled with EML's results and are reported back to the participating contractors 30 days later. A summary of the reported results is available to the participants 3 days after the reporting deadline via a modem-telephone connection to the EML computer. This report presents the results from the analysis of the 38th set of environmental quality assessment samples (QAP XXXVIII) that were received on or before June 2, 1993

  14. Sixth Semiannual Report of the Commission to the Congress: Atomic Energy and the Life Sciences, July 1949

    Energy Technology Data Exchange (ETDEWEB)

    Lilienthal, David E.; Bacher, Robert F.; Pike, Sumner T.; Strauss, Lewis L.

    1949-07-01

    The document represents the sixth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up briefly the major developments in the national atomic energy program and further gives a comprehensive review of one of its major phases -- the biological and medical activities. It outlines the AEC program in all phases of medicine and biology, reviews research results and projects under way, reports what is known of the effects of radiation on man and other living things, and surveys the benefits which may be derived from the use of radiation for diagnosis and treatment of disease and for the study of plants and animals. Since radiation from atomic sources also is potentially harmful to all living things, the Commission has set up safeguards for all who might, without such protection, be exposed to harmful radiation.

  15. Phenomenology of coupled nonlinear oscillators

    Science.gov (United States)

    Estevez-Rams, E.; Estevez-Moya, D.; Aragón-Fernández, B.

    2018-02-01

    A recently introduced model of coupled nonlinear oscillators in a ring is revisited in terms of its information processing capabilities. The use of Lempel-Ziv based entropic measures allows to study thoroughly the complex patterns appearing in the system for different values of the control parameters. Such behaviors, resembling cellular automata, have been characterized both spatially and temporally. Information distance is used to study the stability of the system to perturbations in the initial conditions and in the control parameters. The latter is not an issue in cellular automata theory, where the rules form a numerable set, contrary to the continuous nature of the parameter space in the system studied in this contribution. The variation in the density of the digits, as a function of time is also studied. Local transitions in the control parameter space are also discussed.

  16. Optimal oscillation-center transformations

    International Nuclear Information System (INIS)

    Dewar, R.L.

    1984-08-01

    A variational principle is proposed for defining that canonical transformation, continuously connected with the identity transformation, which minimizes the residual, coordinate-dependent part of the new Hamiltonian. The principle is based on minimization of the mean-square generalized force. The transformation reduces to the action-angle transformation in that part of the phase space of an integrable system where the orbit topology is that of the unperturbed system, or on primary KAM surfaces. General arguments in favor of this definition are given, based on Galilean invariance, decay of the Fourier spectrum, and its ability to include external fields or inhomogeneous systems. The optimal oscillation-center transformation for the physical pendulum, or particle in a sinusoidal potential, is constructed

  17. Local hysteresis in relaxation oscillators

    International Nuclear Information System (INIS)

    Alstroem, P.; Christiansen, B.; Levinsen, M.T.

    1988-01-01

    Relaxation oscillations or 'integrate and fire' phenomena are very commonly found in nature. When modulated by an external force a global hysteresis connected with chaos is often encountered. Besides this kind of hysteresis a local form is found in some systems. We describe briefly the difference and the circumstances under which to observe local hysteresis. A specific system treated in detail is the Fohlmeister model, originally derived to describe a neuronal encoder. In the limit of small damping an analytical solution is obtained. Furthermore, we derive an upper limit to the hysteresis. The results are compared to numerical calculations on the full system and agree quite well. In contrast to e.g. the driven damped pendulum equation the hysteresis is limited in size as compared to the phase-locked region. (orig.)

  18. Oscillating spin-2 dark matter

    Science.gov (United States)

    Marzola, Luca; Raidal, Martti; Urban, Federico R.

    2018-01-01

    The negative outcomes of laboratory searches, juxtaposed with cosmological observations, may indicate that dark matter has a gravitational origin. We show that coherent oscillations of a massive spin-2 field emerging from bimetric theory can easily account for the observed dark matter abundance. The framework, based on the only known consistent extension of general relativity to interacting spin-2 fields, is testable in precision measurements of the electric charge variation by means of atomic clocks, molecular systems, dedicated resonant mass detectors, as well as gravity interferometers and axionlike-particle experiments. These searches, therefore, provide a new window into the phenomenology of gravity which complements the results of dedicated tests of gravitation. We also present a multimetric extension of the scenario that straightforwardly implements the clockwork mechanism for gravity, explaining the apparent weakness of this force.

  19. Quantum wormholes and harmonic oscillators

    Science.gov (United States)

    Garay, Luis J.

    1993-01-01

    The quantum state of a wormhole can be represented by a path integral over all asymptotically Euclidean four-geometries and all matter fields which have prescribed values, the arguments of the wave function, on a three-surface which divides the space time manifold into two disconnected parts. Minisuperspace models which consist of a homogeneous massless scalar field coupled to a Friedmann-Robertson-Walker space time are considered. Once the path integral over the lapse function is performed, the requirement that the space time be asymptotically Euclidean can be accomplished by fixing the asymptotic gravitational momentum in the remaining path integral. It is argued that there does not exist any wave function which corresponds to asymptotic field configurations such that the effective gravitational constant is negative in the asymptotic region. Then, the wormhole wave functions can be written as linear combinations of harmonic oscillator wave functions.

  20. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  1. Oscillating and rotating sine-Gordon system

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1986-01-01

    The interaction between a 2π kink and the background or vacuum is investigated in the pure sine-Gordon system. For an oscillating background (i.e., the k=0 part of the phonon spectrum) the 2π kink oscillates, while for increasing or decreasing vacuum two phenomena have been observed, depending on...... to a Mathieu equation explaining the excitation....

  2. Phase Multistability in Coupled Oscillator Systems

    DEFF Research Database (Denmark)

    Mosekilde, Erik; Postnov, D.E.; Sosnovtseva, Olga

    2003-01-01

    along the orbit of the individual oscillator. Focusing on the mechanisms underlying the appearance of phase multistability, the paper examines a variety of phase-locked patterns. In particular we demonstrate the nested structure of synchronization regions for oscillations with multicrest wave forms...

  3. Synchronization of oscillators in complex networks

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/pram/070/06/1175-1198 ... Abstract. Theory of identical or complete synchronization of identical oscillators in arbitrary networks is introduced. ... Combined theories are used to explore and compare three types of semirandom networks for their efficacy in synchronizing oscillators.

  4. Oscillating systems with cointegrated phase processes

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Rahbek, Anders; Ditlevsen, Susanne

    2017-01-01

    We present cointegration analysis as a method to infer the network structure of a linearly phase coupled oscillating system. By defining a class of oscillating systems with interacting phases, we derive a data generating process where we can specify the coupling structure of a network that resemb...

  5. Electromagnetic Radiation Originating from Unstable Electron Oscillations

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens; Pécseli, Hans

    1975-01-01

    Electromagnetic oscillations in the range 300 – 700 MHz were observed from an unmagnetized argon discharge with an unstable electron velocity distribution function.......Electromagnetic oscillations in the range 300 – 700 MHz were observed from an unmagnetized argon discharge with an unstable electron velocity distribution function....

  6. Discontinuous Spirals of Stable Periodic Oscillations

    DEFF Research Database (Denmark)

    Sack, Achim; Freire, Joana G.; Lindberg, Erik

    2013-01-01

    We report the experimental discovery of a remarkable organization of the set of self-generated periodic oscillations in the parameter space of a nonlinear electronic circuit. When control parameters are suitably tuned, the wave pattern complexity of the periodic oscillations is found to increase...

  7. Lambda Oscillations and the Conservation Laws

    OpenAIRE

    Widom, A.; Srivastava, Y. N.

    1996-01-01

    Lowe, Bassalleck, Burkhardt, Rusek, Stephenson, and Goldman assert, under the assumption of decays at fixed space-time points, that Kaon induced Lambda oscillations disappear. We find, under the same assumption, that energy conservation and momentum conservation also disappear. Ordinary particles can exhibit quantum oscillations.

  8. Mass and oscillations of Dirac neutrinos

    International Nuclear Information System (INIS)

    Collot, J.

    1989-01-01

    In the most economical extension of the standard model, we have presented the theory of massive Dirac neutrinos. We have particularly emphasized that, in this model, a complete analogy between quarks and leptons can be erected and predicts neutrino flavor oscillations. We have reviewed the last experimental results concerning kinetic neutrino mass experiments and neutrino oscillation investigations

  9. Accelerator-based neutrino oscillation searches

    International Nuclear Information System (INIS)

    Whitehouse, D.; Rameika, G.

    1993-01-01

    This paper attempts to summarize the neutrino oscillation section of the Workshop on Future Directions in Particle and Nuclear Physics at Multi-GeV Hadron Beam Facilities. There were very lively discussions about the merits of the different oscillation channels, experiments, and facilities, but the authors believe a substantial consensus emerged

  10. Compensation of oscillation coupling induced by solenoids

    International Nuclear Information System (INIS)

    Zelinskij, A.Yu.; Karnaukhov, I.M.; Shcherbakov, A.A.

    1988-01-01

    Methods for construction of various schemes of oscillation coupling compensation, induced by solenoids in charged particle storage rings, are described. Peculiarities of magnetic structure, enabling to localize oscillation coupling in wide energy range are discussed. Results of calculation of compensation schemes for design of NR-2000 storage ring spin rotation are presented

  11. Natural oscillation frequencies for arbitrary piping systems

    International Nuclear Information System (INIS)

    Gale, J.; Tiselj, I.

    2007-01-01

    This paper concerns axial and lateral oscillations and oscillation frequencies of various empty (natural frequency of oscillation) and fluid filled (forced oscillation) piping systems. Forced oscillations of fluid filled piping systems and corresponding exchange of energy are denominated also Fluid-Structure-Interaction (FSI). Oscillations appear due to various external or internal impacts and are successfully described with eight-equation physical model for simulations of FSI during fast transients. The physical model is solved with characteristic upwind numerical method and is compiled into a computer code. Simulations were compared to the analytical solutions or solutions from the literature whenever was possible. Discussion on results and problems encountered is given. The proposed physical model gives accurate results, and it enables evaluation of natural frequency of arbitrarily loaded, arbitrarily shaped and arbitrarily supported piping systems. Piping systems are rarely empty, thus forced oscillations due to FSI effects were observed and simulated. Application of various fluids pointed out importance of the fluid's compressibility on pipe's axial oscillations. (author)

  12. Phase locking between Josephson soliton oscillators

    DEFF Research Database (Denmark)

    Holst, T.; Hansen, Jørn Bindslev; Grønbech-Jensen, N.

    1990-01-01

    We report observations of phase-locking phenomena between two Josephson soliton (fluxon) oscillators biased in self-resonant modes. The locking strength was measured as a function of bias conditions. A frequency tunability of the phase-locked oscillators up to 7% at 10 GHz was observed. Two coupled...

  13. The 2D κ-Dirac oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Fabiano M., E-mail: fmandrade@uepg.br [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900 Ponta Grossa-PR (Brazil); Silva, Edilberto O., E-mail: edilbertoo@gmail.com [Departamento de Física, Universidade Federal do Maranhão, Campus Universitário do Bacanga, 65085-580 São Luís-MA (Brazil)

    2014-11-10

    In this Letter, 2D Dirac oscillator in the quantum deformed framework generated by the κ-Poincaré–Hopf algebra is considered. The problem is formulated using the κ-deformed Dirac equation. The resulting theory reveals that the energies and wave functions of the oscillator are modified by the deformation parameter.

  14. TRANSVERSE OSCILLATIONS OF SYSTEMS OF CORONAL LOOPS

    International Nuclear Information System (INIS)

    Luna, M.; Oliver, R.; Ballester, J. L.; Terradas, J.

    2009-01-01

    We study the collective kinklike normal modes of a system of several cylindrical loops using the T-matrix theory. Loops that have similar kink frequencies oscillate collectively with a frequency which is slightly different from that of the individual kink mode. On the other hand, if the kink frequency of a loop is different from that of the others, it oscillates individually with its own frequency. Since the individual kink frequency depends on the loop density but not on its radius for typical 1 MK coronal loops, a coupling between kink oscillations of neighboring loops takes place when they have similar densities. The relevance of these results in the interpretation of the oscillations studied by Schrijver and Brown in 2000 and Verwichte et al. in 2004, in which transverse collective loop oscillations seem to be detected, is discussed. In the first case, two loops oscillating in antiphase are observed; interpreting this motion as a collective kink mode suggests that their densities are roughly equal. In the second case, there are almost three groups of tubes that oscillate with similar periods, and therefore their dynamics can be collective, which again seems to indicate that the loops of each group share a similar density. All the other loops seem to oscillate individually and their densities can be different from the rest.

  15. Neutrino oscillations: Present status and outlook

    Indian Academy of Sciences (India)

    Abstract. The status of neutrino oscillations from global data is summarized, with the focus on the three-flavour picture. The status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of recent MiniBooNE results is also discussed. Further- more, an outlook on the measurement of the mixing angle θ13 ...

  16. Parametric resonance in neutrino oscillations in matter

    Indian Academy of Sciences (India)

    Neutrino oscillations in matter can exhibit a specific resonance enhancement - parametric resonance, which is different from the MSW resonance. Oscillations of atmospheric and solar neutrinos inside the earth can undergo parametric enhancement when neutrino trajectories cross the core of the earth. In this paper we ...

  17. Autonomous Duffing-Holmes Type Chaotic Oscillator

    DEFF Research Database (Denmark)

    Tamaševičius, A.; Bumelienė, S.; Kirvaitis, R.

    2009-01-01

    We have designed and built a novel Duffing type autonomous 3rd-order chaotic oscillator. In comparison with the common non-autonomous DuffingHolmes type oscillator the autonomous circuit has an internal positive feedback loop instead of an external periodic drive source. In addition...

  18. Effective harmonic oscillator description of anharmonic molecular ...

    Indian Academy of Sciences (India)

    ... a harmonic oscillator eigenfunction with the centroid and width parameter as variational paraeters. It is found that the effective harmonic oscillator approximation provides a description of the anharmonic eigenstates very similar to the vibrational self consistent field results. Coriolis coupling is also included in these studies.

  19. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-Thomsen, S.; Ditlevsen, Ove Dalager

    1999-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

  20. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-thomsen, Søren; Ditlevsen, Ove Dalager

    1996-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...