9,354 research outputs found

    A mesoscopic approach to diffusion phenomena in mixtures

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    The mesosocpic concept is applied to the theory of mixtures. The aim is to investigate the diffusion phenomenon from a mesoscopic point of view. The domain of the field quantities is extended by the set of mesoscopic variables, here the velocities of the components. Balance equations on this enlarged space are the equations of motion for the mesoscopic fields. Moreover, local distribution functions of the velocities are introduced as a statistical element, and an equation of motion for this distribution function is derived. From this equation of motion differential equations for the diffusion fluxes, and also for higher order fluxes are obtained. These equations are of balance type, as it is postulated in Extended Thermodynamics. The resulting evolution equation for the diffusion flux generalizes the Fick's law

    Long-term forecasting of extreme catastrophic events

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    Abstract (First part: Volcanic, tectonic and oceanic systems). The simple application of the principle of the constancy of the average power to the examined volcanic, tectonic and oceanic systems, has allowed the long term forecasting of their critical state. The same results were obtained by means of the application of the Palumbo map and of its orbit. Both the models emphasize the importance of small events in releasing energy and thence in procrastinating and reducing the intensity of the extreme events. When a system is in a critical state small external excitations may trigger a catastrophe. Such external sources have been identified and their triggering effects were verified in the occurrence of many large events when they were in critical state. These triggering forces are: earth tides, geomagnetic tides, solar activity and seismic waves. Earth tides trigger earthquakes, but their effects may be evidenced on]y on local sìtes. When many globally distributed earthquakes are considered no significant effect is discernible, since any effect is blurred by a multiplicity of unidentified fault orientations and stress regimes. The same does not hold for geomagnetic tides. The significant correlation obtained between geomagnetic tides and large scale earthquakes Is thus attributed to a magnetostrictive effect caused by the external geomagnetic fields and their variations (see the paper: Gravitational and geomagnetic tidal sources of earthquakes triggering). Such an effect may also explain the significant correlation obtained between the large scale earthquakes frequency and the solar activity related to geomagnetic activity. Seismic waves may trigger local earthquakes and volcanic eruptions, when they are in critical states. These has been proved for volcanic eruptions of Vesuvius, and recently for the anomalous frequency of large earthquakes following the very intense event of December 26th in SE Asia. (Second part: a way to explode the myth of green house effect). Ten years ago, there was an international alert caused by the anthropogenic depletion of the ozone layer. It was shown that the phenomenon was due to natural sources (See book n. 1: L’Ecosistema Terra…..) and yet nowadays nobody talks about it any more. The same will happen for the green house effect. The global circulation models are not reliable, and the satellite observations show that the increase of global air temperature is very doubtful, mainly because the historical series of data were almost taken from the records of town stations largely affected by the urban heat island effect. We now propose two different mechanisms to explain the Sun-climate relationship: (i) max solar activity = > min ìncoming cosmic radiation => min clouds and their albedo => max T; (ii) max solar activity and max dynamo in the interior of Earth => max sea surface temperature=> max evaporation => max T. Moreover we will show that the elastic response of the climate system to the last little age, the large increase of solar activity, going on since the last two centuries, and the recent decrease of the largest volcanic eruptions are responsible for the secular variation of the observed global air temperature ‘T”. This would show a negligible influence of the other sources, Iike the green effect. On the other hand, should the greenhouse effect be actual, the increase would be even over than 3 °C in 2050, with an increase never recorded in the history of the Earth, that, therefore, could cause a catastrophe. Some geo-engineering remedies are proposed. The recent secular oceanic rise, attributed by the literature to the increase of green house gas concentration in the atmosphere, is found to be due to the rainfall, to the volcanic eruptions, to the fires and to the mankind waste water discharged in the oceans. Again, should the circulation models proposed by the literature be proved, then an increase around 30 cm should be expected in the next decades, with severe consequences for littorals areas like Venice and the mouths of the Nile

    Rischiare con Dio (Dopo Einstein); Science approaches man to God (After Einstein)

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    Quark and leptons and gravitational, weak electric and the nuclear interactions are respectively the elementary particles and the fundamental forces of Universe. According to the theory of the strings, each particle (fermionic string) corresponds to a force (bosonic string). The papers: The theory of string: a candidate for a generalized unification model has proposed a mathematical relationship that links them. This book starts with simple experiments using a sequence of equal oscillating masses with the same period that are each other originally in contact. Then it shows obviously that when one moves the first mass by a fixed elongation, the motions propagates through the successive masses, so that only the end one moves. Then some casual masses are eliminated and the remaining ones are excited by casual oscillations. The experiments show that the motion of the first mass does not propagate as before, because of the interferences. This allowed to explain why a thermal or an acoustic wave cannot propagate through the vacuum, why this is possible for a photon, why a photon goes around a mass, what is really the diffusion. Then the book goes on with the history of Universe to recall that during the first fractions of billionths of seconds after the big bang, the three fundamental forces acted together and the evolution was very very fast. After the separation of the fundamental forces, it slowered. Then the electromagnetic interaction generated, down in the ocean, the first cell governed by both the gravitational and the electromagnetic interactions and the realm of life evolved with a higher velocity. Later, a quantuum oscillation, related to a cosmic radiation caused by a nuclear interaction, changed the gene of a zygote of a hominid generating a defective egg, i.e. the first man and the realm of thought, governed by the three fundamental interactions that is developing with a marked and increasing rate. The Universe created thus the most recent system “man”, that contains very very worth energy (the thought), that increased the rate of the evolution of the social system. This requires a great increase of the expense of energy ΔE and thus other sources and sort of energy (the nuclear energy). Section 1: “The importance of small events in Nature” has proposed the generalized principle of the constancy of the average power, ΔE/Δt = v x cost. Since for the social system Δt is short because it is related to the time length of the mankind, v must be very high, implying that in next future great modification in the social system are expected. Rischiare con Dio (Dopo Einstein) Il tempo, lo spazio, la massa ed il vuoto sono enti astratti, indipendenti ed estranei alla realtà: energia in continua trasformazione, eterna nella sua mutevolezza. La fisica, evitando di identificarli, ne ha studiato le mutue relazioni, pervenendo a definizioni difficili e complesse, e fornendo rappresentazioni della realtà limitate e ristrette a pochi fenomeni. Nessun modello fisico spiega, infatti, la genesi né riesce a prevedere l’evoluzione di quasi tutti i sistemi naturali perché complessi e caotici, perché non si conosce che cosa sono la complessità e la caoticità e soprattutto perché esistono. Non si sa perché la luce a volte si comporti come particella ed a volte come onda, perché il suo percorso s’incurvi quando incontra un corpo celeste, o venga dispersa quando ne incontra uno estremamente piccolo e perché venga assorbita da un buco nero perché i pianeti orbitino intorno alle stelle. Si ignora che cos’è il vuoto e perché possiede tutte le proprietà del pieno, compresa la capacità di essere attraversato dalle onde elettromagnetiche, di generare campi elettromagnetici, di creare particelle e di fornire l’energia all’universo. Non si conosce che cosa sia la materia e l’energia oscura, dette così perché del tutto ignote anche se costituiscono più del 95% dell’esistente. Perché l’universo si sta espandendo con velocità crescente, perché i quark si respingono con una forza newtoniana inversa in seno ad un protone, Che cosa sono in realtà lo spazio, il tempo, la massa ed il vuoto ? Non sono stati neppure investigati dalla fisica fenomeni concreti come l’attività del sistema nervoso e di quello immunitario, i messaggi dell’arte e tutte le manifestazioni dello spirito, mentre neppure i modelli più avanzati, come la Relatività Generale, in disaccordo con la Meccanica Quantistica e non confermata dalle osservazioni del satellite Wmap appaiono più sicuri e generali. Per queste e molte altre incertezze e limitazioni, i modelli della fisica, vengono continuamente superati, anche se talora l’autorevolezza dei proponenti ne ha consentito una sopravvivenza lunga venti secoli dopo Aristotele, quattro dopo Galileo ed uno dopo Einstein. Sulla validità del metodo sperimentale di Galileo, ripresentato e perfezionato da Karl Popper non si discute. La vastità e l’importanza dei fenomeni e delle realtà ignorate possono, però dar credito a Peirce, secondo il quale i principi stessi della scienza sono vincoli che imprigionano il pensiero. Senza arrivare a tanto legittimo pessimismo, pur nel convincimento che errare sia umano, ma perseverare diabolico, questa investigazione ha seguito Popper, sostituendo una nuova ipotesi a quelle precedenti e basandosi su due soli fondamenti: L’evento iniziale (Big Bang o altro) e la conservazione dell’energia. La forza nucleare forte determinò l’evoluzione catastrofica ed improvvisa del buco nero primordiale, il quale scagliò tutt’intorno pacchetti di energia raggiante, alcuni dei quali si trasformarono perfino in particelle. Gli enti, come lo spazio, il tempo, la massa ed il vuoto furono estranei a quell’evento, caratterizzato soltanto da una successione di stadi evolutivi, a ciascuno dei quali l’uomo ha attribuito un “tempo”, per designarne la posizione della successione ed uno “spazio”, per indicarne e differenziarne la morfologia. Per il principio della conservazione, ciascuna particella si oppone alle forze esterne, mostrando un’inerzia, che Galileo definì “la massa” e che si oppone ancora all’azione di un’onda elettromagnetica disperdendola, oppure costringendola a circuirla. Analogamente, ogni stadio evolutivo, per conservare la propria individualità morfologica (lo spazio) ed il suo ordine nella successione degli stadi (il tempo), reagisce, rispettivamente, all’intrusione di una massa oppure di un tempo nel proprio dominio. Il modello proposto si basa sull’osservazione di altre proprietà, oltre all’isocronismo, scoperto da Galileo nell’oscillazione del sasso da lui utilizzato, osservazioni che il lettore può ripetere facilmente, usando una successione di masse uguali fra loro e sospese a cordicelle di pari lunghezza. Noterà che, se le masse sono a diretto contatto e sposterà la prima di una certa elongazione lasciandola poi cadere sulla seconda, soltanto l’ultima di esse si sposterà dalla posizione originaria di una elongazione più o meno uguale a quella della prima massa. Sottrarrà poi, a caso, alcuni pendoli della successione ed imprimerà a questi oscillazioni casuali diverse fra loro. Ripeterà l’esperimento di prima e noterà che la perturbazione introdotta dallo spostamento della prima massa spostata non si propagherà fino alla fine a causa delle successive interferenze. Potrà allora leggere le prime tre pagine del primo capitolo del testo nel quale è dimostrato che tali esperimenti elementari hanno spiegato perché un’onda acustica o termica non si propaghi nel vuoto, perché invece ciò sia possibile per un fotone, come e perchè avviene il fenomeno della diffusione, perché il percorso di un fotone s’incurva in corrispondenza di una massa. Mediante questi semplici esperimenti e ragionamenti elementari, il libro fa risalire il perché dell’origine dell’universo e della vita, rispettivamente all’inversione della forza newtoniana fra le stringhe o le particelle al disotto di una determinata distanza (A simple models explaining some ideas and discordances in general relatività, point 8), ed alla necessità, per l’evoluzione, di creare un sistema “la vita” più complesso ed interattivo, governato anche dall’interazione elettromagnetica, per conservare il proprio ritmo evolutivo, per il principio gerenalizzato della costanza della potenza media E/t = kv (Section 1, Importanza dei piccoli eventi). Ha attribuito il perché della osservata evoluzione nel sistema universo e nel sistema vita, alla scelta della via più dinamica e più efficiente per la sua realizzazione. Ha infine mostrato la presenza nell’uomo di tutte e tre le forze fondamentali: (i) la radiazione cosmica originata dalla forza nucleare forte, che ha generato l’uomo e ne potenzia l’attività cerebrale e quindi spirituale, (ii) quella elettromagnetica che governa i processi biologici ed ovviamente (iii) quella gravitazionale, alla quale è soggetto tutto ciò che risiede sulla superficie terrestre. Questa posizione privilegiata e singolare nell’universo conferisce all’uomo, al suo destino ed alle sue opere perfino a quelle artistiche, un significato concreto bene interpretabile dalla scienza

    Natural sources of global warming

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    Abstract: The effect of (i) the observed increase of sea surface temperature, responsible for the corresponding increase of the evaporation, (ii) of solar activity and (iii) volcanic explosive eruptions explains 86% of the increase of global air temperature. The contribution of the increased atmospheric concentration of CO2 equivalent (0.15°C) caused an increase of the vapour pressure and thence a decrease of the evaporation. The loss of the consequent greenhouse effect due to such a loss, reduced the net effect of CO2 equivalent on the global air temperature to 0.08°C (0.06 °C of volcanic and 0.02°C of anthropogenic origin). The decrease of evaporation caused by the increase of the global air temperature, plus the direct effect of solar irradiance on the surface of the ocean explain 89% of the observed increase of sea surface temperature

    Energy chirp measurements by means of an RF deflector: a case study the gamma beam source LINAC at ELI-NP

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    RF Deflector (RFD) based measurements are widely used in high–brightness electron LINAC around the world in order to measure the ultra–short electron bunch length. The RFD provides a vertical kick to the particles of the electron bunch according to their longitudinal positions. In this paper, a measurement technique for the bunch length and other bunch proprieties, based on the usage of an RFD, is proposed. The basic idea is to obtain information about the bunch length, energy chirp, and energy spread from vertical spot size measurements varying the RFD phase, because they add contributions on this quantity. The case study is the Gamma Beam System (GBS), the Compton Source being built in the Extreme Light Infrastructure–Nuclear Physics (ELI–NP) facility. The ELEctron Generation ANd Tracking (ELEGANT) code is used for tracking the particles from RFD to the measurement screen

    Path integrals and degrees of freedom in many-body systems and relativistic field theories

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    The identification of physical degrees of freedom is sometimes obscured in the path integral formalism, and this makes it difficult to impose some constraints or to do some approximations. I review a number of cases where the difficulty is overcame by deriving the path integral from the operator form of the partition function after such identification has been made.Comment: 15 pages, volume in honor of prof.Yu.A.Simono

    Investigation of aerothermodynamics and optical radiation in the AFE hypersonic flow field

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    Research for the radiation experiments on the Aeroassist Flight Experiment (AFE) was performed to obtain a data base for development of engineering requirements for aerobrakes. Due to funding restrictions, the necessary Aerobrake design data were obtained from ground based experiments, specifically arc-jet wind tunnels. Except for the instrument windows, final development of the AFE radiometers was completed. Window definition included several designs to be flight validated in arc-jets. This work was completed, and successful designs have evolved which will yield full scientific return from the flight experiment. The theoretical work includes final code development to describe the spacecraft environment to support instrument definition, optical radiation codes that operate at significantly improved speeds, and calculation of radiation forebody loads and effects on experiment objectives for varying AFE weights and trajectories. Furthermore, radiant flux vectors at the AFE base were predicted to be used for afterbody instrument definition. The Vacuum Ultraviolet Experiment for the Arc-Jet was completed, and arc-jet experiment conditions and experiment objectives were refined to incorporate the most current thinking. Ballistic range experiments were completed. Several shadowgraphs indicating corner turning angles and waviness structures were obtained, and the results were used to estimate the compression region location for the AFE flight. The waviness measured has helped to model the temporal variations of wake radiation for purposes of defining radiometers to measure the energy content of wake dynamics
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