Search results for "oscillation"
showing 10 items of 1257 documents
Analytic behavior of the QED polarizability function at finite temperature
2012
We revisit the analytical properties of the static quasi-photon polarizability function for an electron gas at finite temperature, in connection with the existence of Friedel oscillations in the potential created by an impurity. In contrast with the zero temperature case, where the polarizability is an analytical function, except for the two branch cuts which are responsible for Friedel oscillations, at finite temperature the corresponding function is not analytical, in spite of becoming continuous everywhere on the complex plane. This effect produces, as a result, the survival of the oscillatory behavior of the potential. We calculate the potential at large distances, and relate the calcul…
Photo-z optimization for measurements of the BAO radial scale
2009
ArXiv pre-print avaible at:http://arxiv.org/abs/0812.3414
The effect of Transient over Voltages on the Partial Discharges activity in HVDC joints
2021
Rapid growth of HVDC cable line installations is expected in the coming years. Several research groups have investigated dielectric phenomena that occur in the insulation of HVDC cables and accessories that accelerate aging and reduce the reliability of this technology over time. Unlike in HVAC cables, under HVDC stress, the distribution of the electric field inside the insulation layer depends not only on the applied voltage but also on the temperature distribution and on other factors related to manufacturing such as the presence of impurities. Reaching local and transient electric field peaks can enhance the onset of Partial Discharges (PDs) which can lead to premature aging of the insul…
Frequency dynamics of power systems with temporally distributed disturbances
2021
Abstract The frequency dynamics and stability of power systems is essentially affected by nature and characteristics of the disturbances occurring in the system. Conventionally, frequency transients are examined assuming a single disturbance applied at a given time. However, actual incidents in the power systems can be generally composed of a temporal sequence of events, and thus characterized by multiple power imbalances of different magnitudes and time offsets. The consideration of the effects of the temporal distribution of power imbalances is important for two main reasons: the impact on the frequency dynamics of the system in terms of frequency metrics such as minimum instantaneous fre…
Teaching mechanical oscillations using an integrate curriculum
1997
Abstract A set of teaching materials dealing with harmonic oscillations was developed as part of a research project investigating the influence of different pedagogical tools on physics learning. The materials incorporate simulation software and laboratory activities associated with Teacher and Student Units. The project involved research groups at seven Italian universities and the materials have been trialled in high schools nation‐wide. This paper describes the experimental protocol for the use of these materials in pilot classes and the evaluation of student learning and teacher training results. The intervention was found to improve physics education at school praxis level and to promo…
The Dawning of Computational Psychoanalysis
2014
In this paper, the author wishes first to highlight, within the general cultural context, some possible elementary computational psychoanalysis formalizations concerning Matte Blanco's bi-logic components through certain very elementary mathematical tools and notions drawn from theoretical physics and algebra. Afterwards, on the basis of recent work of Giampaolo Sasso (1999; 2005; 2011), relying on the crucial crossroad between neurosciences and psychoanalysis, it will be possible to identify some hints for further formalization attempts turned toward a computational psychoanalysis outlook. Lastly, possible interesting relationships with cognitive informatics are also outlined.
Plasmon mass scale and quantum fluctuations of classical fields on a real time lattice
2018
Classical real-time lattice simulations play an important role in understanding non-equilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy-ion collisions. Above the Debye scale the classical Yang-Mills (CYM) theory can be matched smoothly to kinetic theory. First we study the limits of the quasiparticle picture of the CYM fields by determining the plasmon mass of the system using 3 different methods. Then we argue that one needs a numerical calculation of a system of classical gauge fields and small linearized fluctuations which correspond to quantum fluctuations, in a way that keeps the separation between the two manifest. We demonstra…
Evaluation of cut quality using the Amadeus microkeratome with different settings.
2004
Abstract Purpose: To evaluate the quality of keratectomy specimens created with the Amadeus® microkeratome (AMO) using scanning electron microscopy (SEM). Setting: Johannes Gutenberg-University Hospital, Department of Ophthalmology, Mainz, and the Department of Anatomy, Justus Liebig-University, Giessen, Germany. Methods: Corneal cuts were performed in freshly enucleated pig eyes using the Amadeus microkeratome with 9 combinations of oscillation rate and head-advance speed. For the cutting trials, oscillation rates of 8000, 13000, and 18000 rpm and head-advance speeds of 1.0, 2.5, and 4.0 mm/s were chosen. Fifty-four eyes were included, resulting in 9 groups of 6 eyes for each configuration…
Screening effects in Relativistic Models of Dense Matter at Finite Temperature
1998
We investigate screening effects of the medium on the potential interaction between two static 'charges' for different models of dense plasmas in the one-boson exchange approximation. The potential can exhibit an oscillatory behavior, which is related to the analytic structure of the corresponding boson propagators in the complex $q$-plane. We have first revisited the one-pion exchange in a nuclear medium. In addition to Friedel oscillations, which are associated to branch cuts in the $q$-plane, there appears another oscillatory component, which arises from a pole on the pion propagator. This pole is located appart from the axes, giving rise to an oscillating Yukawa-like potential. Therefor…
Tau Physics 2006: Summary & Outlook
2007
13 páginas, 10 figuras, 2 tablas.-- Comunicación presentada al 9º International Workshop on Tau Lepton Physics (TAU06) celebrado del 19 al 22 de Septiembre en Pisa (Italia).-- arXiv:hep-ph/0702074v1