505 research outputs found
100 cose da sapere per volare sereni : come affrontare il volo senza paura
No full textUn manuale agile e irrinunciabile per tutti coloro che usano l’aereo ma faticano a superare l’ansia del volo, per affrontare il viaggio con maggior serenità e consapevolezza. Una rigorosa spiegazione scientifica alternata a test e consigli pratici, un manuale nuovo ed efficace sui veri problemi dovuti alla paura di volare. Volare significa essere sradicati da terra, non avere più alcun controllo ed essere completamente nelle mani di altri. Per qualcuno questa può essere una situazione tutt'altro che abitudinaria, una condizione vissuta con disagio, se non addirittura con ansia. Ma la paura di volare può essere vinta; è sufficiente che la nostra sfera razionale dialoghi con la sfera emotiva del cervello: solo così possiamo gestire e regolare l'emozione. In questo libro Alberto Pellai, psicologo e noto divulgatore scientifico, e Giuseppe Lapenta, comandante di linea, vi condurranno per mano in un viaggio alla scoperta della natura della vostra ansia e dei "segreti" della cabina di pilotaggio, per capire cosa succede realmente - anche nella vostra testa - durante rullaggio, decollo, turbolenze e atterraggi. L'opera è arricchita da test e strumenti di rilassamento e autovalutazione, e da curiose rubriche che raccontano le emozioni di chi sale a bordo di un velivolo. Un manuale agile per tutti coloro che usano l'aereo ma faticano a superare l'ansia del volo, per affrontare il viaggio con maggior serenità e consapevolezza
Mesoscale Simulation of Nanoparticle Production
No full textWe present a model to study complex physical systems composed by a set of clusters of different chemical species immersed in a matrix with which they interact. The overall model describes the transient of the basic mechanisms governing the processes of interaction in a two-dimensional micrometer size system. At each time step, the continuum (micrometer scale) model computes the macroscopic fields according to the prescribed boundary conditions. The continuum system is discretized with a desired number of uniform computational cells. Each cell contains a number of computational particles which represent the actual particles mixture. The particle-in-cell (discrete) model maps the macroscopic fields from the (continuum) cells to the particles. A molecular dynamics approach is used for computing the chemical reactions among the particles. We present results of a recent application of this approach to the simulation of nanoparticles formation in SHS reactors [1].
[1] G. Zuccaro, G. Lapenta, G. Maizza, Computer Phys. Commun., 162, 89 (2004)
Simulation output from "Multiscale MHD-Kinetic PIC Study of Energy Flux Caused by Reconnection"
No full textResults from an implicit particle-in-cell simulation (IPIC3D) of the energy fluxes from magnetic reconnection in Earth's magnetotail. The results consist of six files in HDF5 format that contain the electric field, magnetic field, the density, velocity and energy flux. Each file contains one time step.
The IPIC3D simulation is described in
Markidis, S., Lapenta, G. and Rizwan-uddin (2010) Multi-scale simulations of plasma with IPIC3D . Mathematics and Computers and Simulation, 80, 1509-1519.
The energy conserving version of IPIC3D used in this study is described in
Lapenta, G., (2017) Exactly energy conserving semi-implicit particle in cell formulation, J. Computational Physics, 334, 349-366.
The application of IPIC3D to Earth's magnetosphere is described in
Walker, R., Lapenta, G., Berchem, J., El-Alaoui, M., and Schriver, D., (2019) Embedding particle-in-cell simulations in global magnetohydrodynamic simulations of the magnetosphere, Journal of Plasma Physics, 85(1)
Models, coproducts and exchangeability: Notes on states on Baire functions
No full textWe discuss exchangeability and independence in the setting of sigma-complete Riesz MV-algebras. We define and link to each other the notions of exchangeability and distribution law for a sequence of observables (i.e. non classical random variables), as well as the notion of independence for a sequence of algebras. We obtain two categorical dualities for sigma-complete Riesz MV-algebras endowed with states and we define a "canonical" state on the coproduct of a sequence of probability Riesz tribes, giving a weak version of de Finetti's result. Finally, we discuss statistical models
Basic Reactor Physics Problems in Fluid-Fuel Recirculated Reactors
No full textThe basic problems of the neutron physics of fluid-fuel multiplying systems are introduced in slug flow conditions and in the presence of delayed emissions from fission. The critical problem is presented and solved. The importance balance and the adjoint equations are then derived and the consistent point kirietics model is formulated. A few selected results are presented and discussed.status: Publishe
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