Search results for "working"
showing 10 items of 2747 documents
Closure to “Stage–Discharge Relationship for an Upstream Inclined Grid with Transversal Bars” by C. Di Stefano and V. Ferro
2016
Anharmonic effects on the dynamic behavior’s of Klein Gordon model’s
2021
Abstract This work completes and extends the Ref. Tchakoutio Nguetcho et al. (2017), in which we have focused our attention only on the dynamic behavior of gap soliton solutions of the anharmonic Klein-Gordon model immersed in a parameterized on-site substrate potential. We expand our work now inside the permissible frequency band. These considerations have crucial effects on the response of nonlinear excitations that can propagate along this model. Moreover, working in the allowed frequency band is not only interesting from a physical point of view, it also provides an extraordinary mathematical model, a new class of differential equations possessing vital parameters and vertical singular …
The UWB-OFDM Channel Analysis in Frequency
2009
In this paper, the ultra-wideband channel with orthogonal frequency division multiplexing (UWB-OFDM) is analyzed in the frequency domain. For UWB-OFDM channels with log-normal fading in the time domain, we show that the amplitude of each subcarrier can be approximated by a Nakagami-m random variable, where the fading parameter, the mean power and the correlation coefficient are expressed in terms of the following parameters: time arrival of the clusters, inter-arrival time of rays inside clusters, and power decay constants of rays and clusters.
Coll Positioning systems: a two-dimensional approach
2006
The basic elements of Coll positioning systems (n clocks broadcasting electromagnetic signals in a n-dimensional space-time) are presented in the two-dimensional case. This simplified approach allows us to explain and to analyze the properties and interest of these relativistic positioning systems. The positioning system defined in flat metric by two geodesic clocks is analyzed. The interest of the Coll systems in gravimetry is pointed out.
Geometry-Based Statistical Modeling of Non-WSSUS Mobile-to-Mobile Rayleigh Fading Channels
2017
In this paper, we present a novel geometry-based statistical model for small-scale non-wide-sense stationary uncorrelated scattering (non-WSSUS) mobile-to-mobile (M2M) Rayleigh fading channels. The proposed model builds on the principles of plane wave propagation to capture the temporal evolution of the propagation delay and Doppler shift of the received multipath signal. This is different from existing non-WSSUS geometry-based statistical channel models, which are based on a spherical wave propagation approach, that in spite of being more realistic is more mathematically intricate. By considering an arbitrary geometrical configuration of the propagation area, we derive general expressions …
A study of the potential influence of frame coolant on HCLL-TBM nuclear response
2007
Abstract Within the European Fusion Technology Programme, the Helium-Cooled Lithium Lead (HCLL) breeding blanket concept is one of the two EU lines to be developed for a long term fusion reactor, in particular with the aim of manufacturing a test blanket module (TBM) to be implemented in ITER. The HCLL-TBM is foreseen to be located in an ITER equatorial port, being housed inside a steel-supporting frame, actively cooled by pressurized water. This supporting frame has been designed to house two different TBMs providing two cavities separated by a dividing plate 20 cm thick. As the nuclear response of HCLL-TBM could vary with the supporting frame configuration and composition, a parametric st…
Analysis of the static and dynamic behaviour of a magnetic liquid seal
1985
A rotating shaft seal, using ferrofluid between biconical truncated magnetic poles, is analysed both in static and dynamic conditions. After solving Laplace's equation and allowing an approximate expression for the magnetic potential, the magnetic forces acting on the working fluid are obtained. It is thus possible to determine the baric field existing in static conditions and the highest tolerable pressure jump. In the case of dynamic working the flow is schematized by two interior regions, where the azimuthal velocity prevails, and four boundary layers on the walls, where meridional transport of fluid takes place. Assuming laminar motion, by means of a perturbation procedure it is possibl…
Standard model higher order corrections to the WW gamma/WWZ vertex
1995
Using the S--matrix pinch technique we obtain to one loop order gauge independent $\gamma W^-W^+$ and $Z W^-W^+$ vertices in the context of the standard model, with all incoming momenta off--shell. We show that the vertices so constructed satisfy simple QED--like Ward identities. These gauge invariant vertices give rise to expressions for the magnetic dipole and electric quadrupole form factors of the $W$ gauge boson, which, unlike previous treatments, satisfy the crucial properties of infrared finiteness and perturbative unitarity.
Design of a Compact Dual Circular-Polarized Antenna for L-Band Satellite Applications
2020
In this paper, we propose the design of a dual circular-polarized antenna for L-band applications (1.1-1.6 GHz). The designed antenna has been developed by considering crossed-dipoles on top of which a circular patch has been placed to properly act on the mutual coupling between the dipoles. The dual circular polarization is achieved by feeding dipoles in quadrature. Moreover, to increase the antenna gain and polarization purity at high elevation angles, a fence of passive monopoles has been added. The proposed antenna can profitably used as primary feed of a low-frequency parabolic reflector.
Application of Rotational Measurements in Stiffness Reconstruction of Beams and Frames
2009
A stiffness reconstruction method is tested when rotational degrees of freedom are added to the dynamic model of the structure. The inverse problem is formulated as a minimization problem in terms of harmonic vibrations of the structure and its finite element model. An example of frame structure is analyzed by numerical simulations. The results of these numerical analyses show that the damage detection appeared to be much more effective when the angular amplitudes of harmonic vibrations are acquired. This makes very good prospects for the future applications of angular sensors in damage detection of structures.