1,721,191 research outputs found
Enrico Crispolti, Luca Maria Patella. Hanno caldo al cubo
No full textAttraverso una serie di conversazioni inedite tra Enrico Crispolti e Luca Maria Patella e uno scritto teorico di Patella, annotati da Raffaele Bedarida e Antonio Petrone con puntuali riferimenti storico-critici, il volume ripercorre l'intera ricerca dell'artista dagli esordi alla fine degli anni Cinquanta fino al 2000, data delle conversazioni. Spaziando dalla pittura alla fotografia, dal cinema alla performance, illustrato da 65 immagini in bianco e nero e 16 a colori, ed introdotto da una nota storiografica di Bedarida, il libro è uno strumento fondamentale per approfondire non solo il lavoro di Patella ma i molti ambienti e situazioni artistiche in cui è intervenuto da protagonista senza mai lasciarsi incasellare
The Trump of «make America great again»:a further populist alternative? Between latin american influences and the tradition of the people’s party
No full textThe present research article starts from the hypothesis of populism as a reaction to traditional representative democracy. As an acquisition by the people, of their own decision-making dimension. In this context, the Trump political case is analyzed with a qualitative methodology over its communicative strategy and the political measures of the early first months of his presidency aiming to place his belongings to the canons of the tradition of North American populism or even Latin American
G. Petrone (a cura di). Le passioni della retorica, Palermo 2004
No full textReview of G. Petrone (a cura di). Le passioni della retorica, Palermo 200
The Trump of «make America great again»:a further populist alternative? Between latin american influences and the tradition of the people’s party
Full text linkThe present research article starts from the hypothesis of populism as a reaction to traditional representative democracy. As an acquisition by the people, of their own decision-making dimension. In this context, the Trump political case is analyzed with a qualitative methodology over its communicative strategy and the political measures of the early first months of his presidency aiming to place his belongings to the canons of the tradition of North American populism or even Latin American
Direct observation of the solvent organization and nuclear vibrations of [Ru(dcbpy)2(NCS)2]4-, [dcbpy = (4,4′-dicarboxy-2,2′-bipyridine)],: Via ab initio molecular dynamics
No full textEnvironmental effects can drastically influence the optical properties and photoreactivity of molecules, particularly in the presence of polar and/or protic solvents. In this work we investigate a negatively charged Ru(ii) complex, [Ru(dcbpy)2(NCS)2]4- [dcbpy = (4,4′-dicarboxy-2,2′-bipyridine)], in water solution, since this system belongs to a broader class of transition-metal compounds undergoing upon photo-excitation rapid and complex charge transfer (CT) dynamics, which can be dictated by structural rearrangement and solvent environment. Ab initio molecular dynamics (AIMD) relying on a hybrid quantum/molecular mechanics scheme is used to probe the equilibrium microsolvation around the metal complex in terms of radial distribution functions of the main solvation sites and solvent effects on the overall equilibrium structure. Then, using our AIMD-based generalized normal mode approach, we investigate how the ligand vibrational spectroscopic features are affected by water solvation, also contributing to the interpretation of experimental Infra-Red spectra. Two solvation sites are found for the ligands: the sulfur and the oxygen sites can interact on average with ∼4 and ∼3 water molecules, respectively, where a stronger interaction of the oxygen sites is highlighted. On average an overall dynamic distortion of the C2 symmetric gas-phase structure was found to be induced by water solvation. Vibrational analysis reproduced experimental values for ligand symmetric and asymmetric stretchings, linking the observed shifts with respect to the gas-phase to a complex solvent distribution around the system. This is the groundwork for future excited-state nuclear and electronic dynamics to monitor non-equilibrium processes of CT excitation in complex environments, such as exciton migration in photovoltaic technologies. This journal i
Second-Order Mass-Weighting Scheme for Atom-Centered Density Matrix Propagation Molecular Dynamics
No full textThe atom-centered density matrix propagation (ADMP) method is an extended Lagrangian approach to ab initio molecular dynamics, which includes the density matrix in an orthonormalized atom-centered Gaussian basis as additional, fictitious, electronic degrees of freedom, classically propagated along with the nuclear ones. A high adiabaticity between the nuclear and electronic subsystems is mandatory in order to keep the trajectory close to the Born-Oppenheimer (BO) surface. In this regard, the fictitious electronic mass μ, being a symmetric, nondiagonal matrix in its most general form, represents a free parameter, exploitable to optimize the propagation of the electronic density. Although mass-weighting schemes in ADMP exist, a systematic procedure to define an optimal value of the fictitious masses is not available yet. In this work, in order to rationally evaluate the electronic mass, fictitious electronic normal modes are defined through the diagonalization of the Hessian of the electronic density matrix. If the same frequency is imposed on all such modes (compatible with the chosen integration time step), then the corresponding μ matrix can be calculated and then employed for the following propagation. Analysis of several ADMP test simulations reveals that such Hessian-based mass-weighting approach is able to ensure, together with a 0.1/0.2 fs time steps, a high separation between the (real) nuclear and the (fictitious) electronic frequencies, which determines a high adiabaticity. This high, unprecedented, accuracy in the propagation leads, in turn, to low errors in the estimated nuclear vibrational frequencies, making the ADMP method totally comparable to a fully converged BO molecular dynamics simulation but more computationally efficient. This work, therefore, contributes to a further development of the ADMP ab initio molecular dynamics method, aimed at improving its accuracy through a more rational evaluation of the fictitious electronic mass parameter
Quantum confinement effects on optical transitions in nanodiamonds containing nitrogen vacancies
No full textColored nitrogen-vacancy (NV) centers in nanosize diamonds (d∼5 nm) are promising probe materials because their optical transitions are sensitive to mechanical, vibrational, and spin changes in the surroundings. Here, a linear response time-dependent density functional theory approach is used to describe the optical transitions in several NV-doped diamond quantum dots (QDs) in order to investigate size effects on the absorption spectra. By computing the full optical spectrum up to band-to-band transitions, we analyze both the localized “pinned” midgap and the charge-transfer excitations for an isolated reduced NV center. Subband charge-transfer excitations are shown to be size dependent, involving the excitation of the dopant sp3 electrons to the diamond conduction band. Additionally, the NV-doped systems exhibit characteristic sp3−sp3 excitations whose experimental energies are reproduced well and do not depend on QD size. However, the NV position and global cluster symmetry can affect the amount of the energy splitting of the vertical excitation energies of the midgap transitions
Study of a Novel Motion Platform for Flight Simulators using an Anthropomorphic Robot
No full textCurrently most motion platforms for flight simulators are built upon a parallel actuation structure known as Stewart's Platform which is proven to reproduce realistic motion cues. The envelope of reproducible static accelerations and continuous rotational motions is small because of the limited working space of the platform. An alternative to parallel actuation is serial actuation; industrial robots are typical serial actuations systems and are capable of moving large loads with high acceleration and velocities. Although industrial robots suffer less structure stiffness, less load capability and less bandwidth than parallel actuation systems, the large dexterity envelope of the robot motions allows to move the cabin along complex coordinated trajectories, and reach any attitude allowing for reproduction of a wider envelope of accelerations and angular velocities. This paper will show the results of a preliminary study on robot kinematics, the selection of the home position which maximizes the capability to generate velocities and angular rates for the cabin, the design of the wash-out filters and finally some experimental results using an industrial robot, a real-time aircraft simulator with Synthetic Environment, and an inertial unit which is used to measure actual angular rates and accelerations of the cabin in order to assess the motion platform performance
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