Search results for " rotation"
showing 10 items of 278 documents
High X-Ray Luminosity from Dynamo Stars
1981
In the present work we intend to show that a stellar dynamo mechanism can produce high X-ray luminosities and also give account for modulation periods of the order thousand seconds or larger.
Induction mechanisms in a von Kármán swirling flows of liquid Gallium
2004
International audience; Using in situ magnetic field measurements, we study the induction mechanisms in a swirling flow of liquid Gallium generated inside a cylinder, in the gap between two coaxial rotating discs. The von Kármán flow generated in this manner has both helicity and differential rotation. Magnetic Reynolds numbers Rm up to 7 (based on the disc rim speed) are generated. We study the magnetic induction when an external field is applied successively along the axis, in the azimuthal direction or tranverse to the axis of rotation. In the first two cases, both the flow and the magnetic field are axisymmetric, and an effective mechanism of conversion from poloidal to toroidal field e…
The Sun as an X-ray star: Active region evolution, rotational modulation, and implications for stellar X-ray variability
2004
We study the contribution of an active region and its core to the luminosity and the spectrum of the Sun in the X-ray band and to the relevant solar emission measure vs. temperature distribution, EM(T). We also study the relevant changes in the course of four solar rotations, and the solar rotational modulation due to this active region, the only one present at that time. To this end, we have used a large sample of full-disk Yohkoh/SXT observations taken between July and October 1996, covering most of the active region evolution. From the Yohkoh/SXT data we have synthesized the X-ray spectra of the whole solar corona, and the focal plane data as they would be collected with Rosat/PSPC, XMM-…
Evidence for Magnetic Rotation in the Light Tin Region
2000
Lifetimes have been measured for three M1 bands in light Sn/Cd nuclei using the DSAM technique. B(M1) values deduced from these measurements show a rapid decrease with increasing spin for a given configuration. The results have been compared with both Tilted axis cranking and semi-empirical model calculations. These suggest that the shears mechanism is present in this mass region, and that the band in 106Sn appears to be the first example of almost pure magnetic rotation.
Polarizability and optical rotation calculated from the approximate coupled cluster singles and doubles CC2 linear response theory using cholesky dec…
2004
A new implementation of the approximate coupled cluster singles and doubles CC2 linear response model using Cholesky decomposition of the two-electron integrals is presented. Significantly reducing storage demands and computational effort without sacrificing accuracy compared to the conventional model, the algorithm is well suited for large-scale applications. Extensive basis set convergence studies are presented for the static and frequency-dependent electric dipole polarizability of benzene and C60, and for the optical rotation of CNOFH2 and (−)-trans-cyclooctene (TCO). The origin-dependence of the optical rotation is calculated and shown to persist for CC2 even at basis set convergence. …
Spatially variable rate herbicide application on durum wheat in Sicily
2004
Using the conventional farming system, durum wheat requires high rates of herbicide spraying. Herbicide residues can cause pollution of soil and ground water and, therefore, of the entire environment. In order to minimise the environmental impact of herbicides, a home made system for spatially variable rate crop input application was designed, developed and set up by the Department of Engineering and Technologies in Agriculture and Forestry (I.T.A.F.). This system consists of a DGPS, a portable computer, a specifically developed software and a device for applying rates proportionally related to the machine forward speed (DPA). Tests of spatially variable rate herbicide application were carr…
Rovibrational structure of the Ar–CO complex based on a novel three-dimensional ab initio potential
2002
The first three-dimensional ab initio intermolecular potential energy surface of the Ar–CO van der Waals complex is calculated using the coupled cluster singles and doubles including connected triples model and the augmented correlation-consistent polarized valence quadruple zeta (aug-cc-pVQZ) basis set extended with a (3s3p2d1f1g) set of midbond functions. The three-dimensional surface is averaged over the three lowest vibrational states of CO. Rovibrational energies are calculated up to 50 cm−1 above the ground state, thus enabling comprehensive comparison between theory and available experimental data as well as providing detailed guidance for future spectroscopic investigations of highe…
Study of the benzene⋅N2 intermolecular potential-energy surface
2003
The intermolecular potential-energy surface pertaining to the interaction between benzene and N2 is investigated theoretically and experimentally. Accurate intermolecular interaction energies are evaluated for the benzene–N2 van der Waals complex using the coupled cluster singles and doubles including connected triples [CCSD(T)] method and the aug-cc-pVDZ basis set extended with a set of 3s3p2d1f1g midbond functions. After fitting the energies to an analytic function, the intermolecular Schrödinger equation is solved to yield energies, rotational constants, and Raman-scattering coefficients for the lowest intermolecular levels of several benzene–N2 isotopomers. Experimentally, intermolecula…
Computational and experimental investigation of intermolecular states and forces in the benzene-helium van der Waals complex
2003
A study of the intermolecular potential-energy surface (IPS) and the intermolecular states of the perprotonated and perdeuterated benzene–He complex is reported. From a fit to ab initio data computed within the coupled cluster singles and doubles including connected triples model for 280 interaction geometries, an analytic IPS including two- to four-body atom–atom terms is obtained. This IPS, and two other Lennard-Jones atom–atom surfaces from the literature, are each employed in dynamically exact (within the rigid-monomer approximation) calculations of J = 0 intermolecular states of the isotopomers. Rotational constants and Raman-scattering coefficients for intermolecular vibrational trans…
A Survey of Teacher Perceptions of the School Psychologist's Skills in the Consultation Process An Exploratory Factor Analysis
2004
The main purpose of this study is to present the construction and validation process of an instrument designed to evaluate the professional skills of the school psychologist in the teacher consultation process. Initially, an extensive list of items was created which evaluated the characteristics of school psychologists in this area. After carrying out a pilot study and making the necessary modi.cations, we presented the scale to a sample of 157 primary and secondary public school teachers in the Valencian Community. An exploratory factor analysis was carried out on the main components, applying the corresponding varimax rotation. The results show a factorial structure made up of three comp…