Lagrange (1736-1813): a life in mathematics

We retrace the scientific biography of Joseph-Louis Lagrange, entirely dedicated to the study of mathematics, from the time when, still adolescent, he abandoned the studies of law which were a family tradition. His existence was divided almost equally into three periods: Turin (1736–1766) where he was born and composed his first fundamental memoirs on vibrating strings and the calculus of variations; Berlin (1766–1787) at the Academy of Frederick II of Prussia, where he published many works and drafted his 'Méchanique analitique'; and Paris (1787–1813), during the time of the French Revolution and the Napoleonic Empire, where he published his treatises and received the highest honours. Here we present the few significant events of his private life and the many results with which he enriched almost all the mathematical sciences

CONDORCET ET L’ITALIE: LA VIE DE VOLTAIRE ET LES ÉLOGES D’EULER ET DE D’ALEMBERT

Regarding Condorcet's relations with Italian scholars before the French Revolution, the research in Italy of materials for the edition of Kehl of Voltaire's works and the reprints of the scientific biographies of two of the major mathematicians of the eighteenth century, Euler and d'Alembert, are relevant: For the first question, letters are presented with the Bolognese scientist Alfonso Bonfioli Malvezzi, who during his trip to Europe had met Voltaire and Condorcet. The eulogy of d'Alembert can be compared with the posthumous one by Paolo Frisi

Gaspard Monge et le laboratoire institutionnel de la République Romaine : les Ecoles polytechniques

Quand j’ai étudié la République Romaine de 1798-99 en tant qu’éditeur de la correspondance d’Italie de Gaspard Monge, commissaire de la République française, j’ai été très surpris par la modeste considération dont elle jouissait, malgré les travaux significatifs de Dufourcq, Godechot, Giuntella, de De Felice et d’autres plus récents (Formica etc.). J’ai été touché, en particulier, par la comparaison avec la République Napolitaine justement admirée pour ses martyrs, mais née tout de même de la..

Planar differential antenna for short-range UWB pulse radar sensor

A novel planar differential ultrawideband (UWB) antenna was designed and implemented on low-cost FR4 substrate and characterized experimentally. The dedicated design was motivated by the implementation of a UWB pulse radar sensor obtained by co-integrating a system-on-a-chip UWB pulse radar packaged in QFN32 package with the proposed antenna, one for the transmitter and one for the receiver. The experimental results confirm the predictions obtained by simulations, and the effectiveness of the novel antenna design for the implementation of low-cost short-range pulse radar sensor was validated by field operational tests

Quantum crossover in moderately damped epitaxial NbN/MgO/NbN junctions with low critical current density

High quality epitaxial NbN/MgO/NbN Josephson junctions have been realized with MgO barriers up to a thickness of d=1 nm. The junction properties coherently scale with the size of barrier, and low critical current densities down to 3 A/cm$^2$ have been achieved for larger barriers. In this limit, junctions exhibit macroscopic quantum phenomena for temperatures lower than 90 mK. Measurements and junction parameters support the notion of a possible use of these devices for multiphoton quantum experiments, taking advantage of the fast non equilibrium electron-phonon relaxation times of NbN

The exact solution to the Shallow water Equations Riemann problem at width jumps in rectangular channels

Riemann problems at geometric discontinuities are a classic and fascinating issue of hydraulics. In the present paper, the complete solution to the Riemann problem of the one-dimensional Shallow water Equations at monotonic width discontinuities is presented. This solution is based on the assumption that the relationship between the states immediately to the left and to the right of the discontinuity is a stationary weak solution of the one-dimensional variable-width Shallow water Equations. It is demonstrated that the solution to the Riemann problem always exists and it is unique, but there are cases where three solutions are possible. The appearance of multiple solutions is connected to a phenomenon, known as hydraulic hysteresis, observed for supercritical flow in contracting channel. The analysis of a Finite Volume numerical scheme from the literature (Cozzolino et al. 2018b) shows that the algorithm captures the solution with supercritical flow through the width discontinuity when multiple solutions are possible. Interestingly, the one-dimensional variable-width Shallow water Equations are formally identical to the one-dimensional Porous Shallow water Equations, implying that the exact solutions and the numerical scheme discussed in the present paper are relevant for two-dimensional Porous Shallow water numerical models aiming at urban flooding simulations. The exact solution presented here may be used not only as a benchmark, but also as a guide for the construction of new algorithms, and it can be even embedded in an exact solver

Le Università minori in Italia nel 19. secolo

Il tema delle università minori mette bene in evidenza come la diversità di tradizioni e di storia degli stati preunitari abbia portato a notevoli squilibri quantitativi e qualitativi dopo l'Unità e come la mancanza di una reale volontà politica e di un chiaro disegno complessivo coerente, assieme alle resistenze localistiche, siano alla base del fallimento dei tentativi astratti di razionalizzare territorialmente il sistema dell'istruzione superiore e di elevarne il livello qualitativo, sopprimendo semplicemente le unità più marginali e periferiche, che molto spesso hanno però salde radici nelle società locali e stretti rapporti con le loro istituzioni. Il presente testo cerca di dare un contributo alle ricerche che si stanno sviluppando sul tema più generale della storia dell'università italiana fra Otto e Novecento

Risparmio energetico con gli eiettori

L’automazione industriale moderna presuppone sistemi pneumatici performanti, efficienti e a basso consumo energetico. In operazioni pick-and-place con ventose è quindi fondamentale utilizzare eiettori efficienti e soluzioni circuitali che utilizzano serbatoi di accumulo del vuoto

Optimización de la estructura del semirremolque usando acero de alta resistencia para el transporte de GLP

En la presente tesis se optimiza la estructura del semirremolque de un tanque cisterna para transportar 15300 galones de GLP realizando cálculos bajo el código ASME BPVC sección XII y ANSI/AISC 360-16, mediante el método de elementos finitos en el software SolidWorks Simulation, usando 3 tipos de acero: ASTM A-36, ASTM SA 414 grado G y Strenx 700 MC, msiendo este último, el más favorable. El chasis tiene espesores de 6.35, 3.2, 3.2 y 6.35 mm para el ala superior e inferior de largueros, alma de largueros, alma transversal central y ala superior de transversal respectivamente y se redujo la altura de alma de tranversales de chasis en 260 mm; para el king-pin, un espesor de 6.35 mm para los largueros y transversales y una altura desde 136 a 231 mm. Usando acero ASTM A-36, el king-pin soporta un esfuerzo máximo de 1.241*108 Pa con deformación de 0.5 mm, el chasis, 5.679*107 Pa con 0.311 mm; con acero ASTM SA 414 grado G, el king-pin, 4.153*106 Pa con 0.4455 mm y el chasis, 1.651*107 Pa con 0.2743 mm; con acero Strenx 700 MC, el king-pin, 5.698*107 Pa con 0.08572 mm y el chasis, 6.941*107 Pa con 0.7938 mm. El factor de seguridad de toda la estructura supera el 3.5 recomendado por Tresca, en consecuencia, no falla. Se logra optimizar teóricamente la carga útil de GLP en 27700 kg sin restringir la norma peruana D.S. N° 058-2003-MTC, siendo la distancia a recorrer para recuperar la inversión inicial de 69569.48 km en aproximadamente 53 viajes.Tesi