790 resultados para atom economy
Resumo:
In this thesis some of the most important issues presently debated on international sustainability are analysed. The thesis is composed of five independent studies that tackle organically the following issues: the maritime transport externalities, the environmental Kuznets curve, the responsibilities in the carbon dioxide emissions and the integrated approach that have to be used to translate the principles of sustainability into policy. The analysis will be instrumental to demonstrating that sustainability, being a matter of economy, society and environment, requires to be analysed in a transdisciplinary perspective. Using an integrated approach to analyse the relationships between economy and environment, this thesis highlight that sustainability management requires joint economic instruments, integrated analysis, societal behavioural changes as well as responsibilities shifting.
Resumo:
The present work, then, is concerned with the forgotten elements of the Lebanese economy, agriculture and rural development. It investigates the main problematic which arose from these forgotten components, in particular the structure of the agricultural sector, production technology, income distribution, poverty, food security, territorial development and local livelihood strategies. It will do so using quantitative Computable General Equilibrium (CGE) modeling and a qualitative phenomenological case study analysis, both embedded in a critical review of the historical development of the political economy of Lebanon, and a structural analysis of its economy. The research shows that under-development in Lebanese rural areas is not due to lack of resources, but rather is the consequence of political choices. It further suggests that agriculture – in both its mainstream conventional and its innovative locally initiated forms of production – still represents important potential for inducing economic growth and development. In order to do so, Lebanon has to take full advantage of its human and territorial capital, by developing a rural development strategy based on two parallel sets of actions: one directed toward the support of local rural development initiatives, and the other directed toward intensive form of production. In addition to its economic returns, such a strategy would promote social and political stability.
Resumo:
Wir untersuchen die Mathematik endlicher, an ein Wärmebad gekoppelter Teilchensysteme. Das Standard-Modell der Quantenelektrodynamik für Temperatur Null liefert einen Hamilton-Operator H, der die Energie von Teilchen beschreibt, welche mit Photonen wechselwirken. Im Heisenbergbild ist die Zeitevolution des physikalischen Systems durch die Wirkung einer Ein-Parameter-Gruppe auf eine Menge von Observablen A gegeben: Diese steht im Zusammenhang mit der Lösung der Schrödinger-Gleichung für H. Um Zustände von A, welche das physikalische System in der Nähe des thermischen Gleichgewichts zur Temperatur T darstellen, zu beschreiben, folgen wir dem Ansatz von Jaksic und Pillet, eine Darstellung von A zu konstruieren. Die Vektoren in dieser Darstellung definieren die Zustände, die Zeitentwicklung wird mit Hilfe des Standard Liouville-Operators L beschrieben. In dieser Doktorarbeit werden folgende Resultate bewiesen bzw. hergeleitet: - die Konstuktion einer Darstellung - die Selbstadjungiertheit des Standard Liouville-Operators - die Existenz eines Gleichgewichtszustandes in dieser Darstellung - der Limes des physikalischen Systems für große Zeiten.
Resumo:
L’elaborato finale presentato per la tesi di Dottorato analizza e riconduce a unitarietà, per quanto possibile, alcune delle attività di ricerca da me svolte durante questi tre anni, il cui filo conduttore è l'impatto ambientale delle attività umane e la promozione dello sviluppo sostenibile. Il mio filone di ricerca è stato improntato, dal punto di vista di politica economica, sull'analisi storica dello sviluppo del settore agricolo dall'Unità d'Italia ai giorni nostri e dei cambiamenti avvenuti in contemporanea nel contesto socio-economico e territoriale nazionale, facendo particolare riferimento alle tematiche legate ai consumi e alla dipendenza energetica ed all'impatto ambientale. Parte della mia ricerca è stata, infatti, incentrata sull'analisi dello sviluppo della Green Economy, in particolare per quanto riguarda il settore agroalimentare e la produzione di fonti di energia rinnovabile. Enfasi viene posta sia sulle politiche implementate a livello comunitario e nazionale, sia sul cambiamento dei consumi, in particolare per quanto riguarda gli acquisti di prodotti biologici. La Green Economy è vista come fattore di sviluppo e opportunità per uscire dall'attuale contesto di crisi economico-finanziaria. Crisi, che è strutturale e di carattere duraturo, affiancata da una crescente problematica ambientale dovuta all'attuale modello produttivo, fortemente dipendente dai combustibili fossili. Difatti la necessità di cambiare paradigma produttivo promuovendo la sostenibilità è visto anche in ottica di mitigazione del cambiamento climatico e dei suoi impatti socio-economici particolare dal punto di vista dei disastri ambientali. Questo punto è analizzato anche in termini di sicurezza internazionale e di emergenza umanitaria, con riferimento al possibile utilizzo da parte delle organizzazioni di intervento nei contesti di emergenza di tecnologie alimentate da energia rinnovabile. Dando così una risposta Green ad una problematica esacerbata dall'impatto dello sviluppo delle attività umane.
Resumo:
In this thesis, I present the realization of a fiber-optical interface using optically trapped cesium atoms, which is an efficient tool for coupling light and atoms. The basic principle of the presented scheme relies on the trapping of neutral cesium atoms in a two-color evanescent field surrounding a nanofiber. The strong confinement of the fiber guided light, which also protrudes outside the nanofiber, provides strong confinement of the atoms as well as efficient coupling to near-resonant light propagating through the fiber. In chapter 1, the necessary physical and mathematical background describing the propagation of light in an optical fiber is presented. The exact solution of Maxwell’s equations allows us to model fiber-guided light fields which give rise to the trapping potentials and the atom-light coupling in the close vicinity of a nanofiber. Chapter 2 gives the theoretical background of light-atom interaction. A quantum mechanical model of the light-induced shifts of the relevant atomic levels is reviewed, which allows us to quantify the perturbation of the atomic states due to the presence of the trapping light-fields. The experimental realization of the fiber-based atom trap is the focus of chapter 3. Here, I analyze the properties of the fiber-based trap in terms of the confinement of the atoms and the impact of several heating mechanisms. Furthermore, I demonstrate the transportation of the trapped atoms, as a first step towards a deterministic delivery of individual atoms. In chapter 4, I present the successful interfacing of the trapped atomic ensemble and fiber-guided light. Three different approaches are discussed, i.e., those involving the measurement of either near-resonant scattering in absorption or the emission into the guided mode of the nanofiber. In the analysis of the spectroscopic properties of the trapped ensemble we find good agreement with the prediction of theoretical model discussed in chapter 2. In addition, I introduce a non-destructive scheme for the interrogation of the atoms states, which is sensitive to phase shifts of far-detuned fiber-guided light interacting with the trapped atoms. The inherent birefringence in our system, induced by the atoms, changes the state of polarization of the probe light and can be thus detected via a Stokes vector measurement.
Resumo:
Diese Dissertation demonstriert und verbessert die Vorhersagekraft der Coupled-Cluster-Theorie im Hinblick auf die hochgenaue Berechnung von Moleküleigenschaften. Die Demonstration erfolgt mittels Extrapolations- und Additivitätstechniken in der Single-Referenz-Coupled-Cluster-Theorie, mit deren Hilfe die Existenz und Struktur von bisher unbekannten Molekülen mit schweren Hauptgruppenelementen vorhergesagt wird. Vor allem am Beispiel von cyclischem SiS_2, einem dreiatomigen Molekül mit 16 Valenzelektronen, wird deutlich, dass die Vorhersagekraft der Theorie sich heutzutage auf Augenhöhe mit dem Experiment befindet: Theoretische Überlegungen initiierten eine experimentelle Suche nach diesem Molekül, was schließlich zu dessen Detektion und Charakterisierung mittels Rotationsspektroskopie führte. Die Vorhersagekraft der Coupled-Cluster-Theorie wird verbessert, indem eine Multireferenz-Coupled-Cluster-Methode für die Berechnung von Spin-Bahn-Aufspaltungen erster Ordnung in 2^Pi-Zuständen entwickelt wird. Der Fokus hierbei liegt auf Mukherjee's Variante der Multireferenz-Coupled-Cluster-Theorie, aber prinzipiell ist das vorgeschlagene Berechnungsschema auf alle Varianten anwendbar. Die erwünschte Genauigkeit beträgt 10 cm^-1. Sie wird mit der neuen Methode erreicht, wenn Ein- und Zweielektroneneffekte und bei schweren Elementen auch skalarrelativistische Effekte berücksichtigt werden. Die Methode eignet sich daher in Kombination mit Coupled-Cluster-basierten Extrapolations-und Additivitätsschemata dafür, hochgenaue thermochemische Daten zu berechnen.
Resumo:
L'elaborato si propone di indagare il tema della Sharing Economy e i relativi presupposti di sviluppo, studiando casi realmente esistenti. Si affronta la ricerca validando i modelli ipotizzati per ricercare e confrontare le soluzioni esistenti al fine di trovare le caratteristiche ritenute fondamentali per la digital sharing economy.
Resumo:
In questo elaborato viene spiegato il funzionamento di un generico cementificio, come vengono gestiti i rifiuti sia in Italia che in Europa con un focus sulla gestione dei rifiuti in Umbria e infine cosa sia il CSS e come può essere utilizzato come co-combustibile in un forno di una cementeria con conseguente valutazione economica e ambientale.
Resumo:
na provide students with motivation for the study of quantum mechanics. That microscopic matter exists in quantized states can be demonstrated with modem versions of historic experiments: atomic line spectra (I), resonance potentials, and blackbody radiation. The resonance potentials of mercury were discovered by Franck and Hertz in 1914 (2). Their experiment consisted of bombarding atoms by electrons, and detecting the kinetic energy loss of the scattered electrons (3). Prior to the Franck-Hertz experiment, spectroscopic work bv Balmer and Rvdbere revealed that atoms emitted radiatibn at discrete ekergiis. The Franck-Hertz experiment showed directly that auantized enerm levels in an atom are real, not jist optiEal artifacts. atom can be raised to excited states by inelastic collisions with electrons as well as lowered from excited states by emission of photons. The classic Franck-Hertz experiment is carried out with mercury (4-7). Here we present an experiment for the study of resonance potentials using neon.
Resumo:
We tested whether the better subjective exercise tolerance perceived by mountaineers after altitude acclimatization relates to enhanced exercise economy. Thirty-two mountaineers performed progressive bicycle exercise to exhaustion at 490 m and twice at 5533 m (days 6–7 and day 11), respectively, during an expedition to Mt. Muztagh Ata. Maximal work rate (Wmax) decreased from mean ± SD 356 ± 73 watts at 490 m to 191 ± 49 watts and 193 ± 45 watts at 5533 m, days 6–7 and day 11, respectively; corresponding maximal oxygen uptakes (VO2max) were 50.7 ± 9.5, 26.3 ± 5.6, 24.7 ± 7.0 mL/min/kg (P = 0.0001 5533 m vs 490 m). On days 6–7 (5533 m), VO2 at 75% Wmax (152 ± 37 watts) was 1.75 ± 0.45 L/min, oxygen saturation 68 ± 8%. On day 11 (5533 m), at the same submaximal work rate, VO2 was lower (1.61 ± 0.47 L/min, P < 0.027) indicating improved net efficiency; oxygen saturation was higher (74 ± 7%, P < 0.0004) but ratios of VO2 to work rate increments remained unchanged. On day 11, mountaineers climbed faster from 4497 m to 5533 m than on days 5–6 but perceived less effort (visual analog scale 50 ± 15 vs 57 ± 20, P = 0.006) and reduced symptoms of acute mountain sickness. We conclude that the better performance and subjective exercise tolerance after acclimatization were related to regression of acute mountain sickness and improved submaximal exercise economy because of lower metabolic demands for non-external work-performing functions.
Resumo:
The synthesis of cyclic polystyrene (Pst) with an alkoxyamine functionality has been accomplished by intramolecular radical coupling in the presence of a nitroso radical trap Linear alpha,omega-dibrominated polystyrene, produced by the atom transfer radical polymerization (ATRP) of styrene using a dibrominated initiator, was subjected to chain-end activation via the atom transfer radical coupling (ATRC) process under pseudodilute conditions in the presence of 2-methyl-2-nitrosopropane (MNP). This radical trap-assisted, intramolecular ATRC (RTA-ATRC) produced cyclic polymers in greater than 90% yields possessing < G > values in the 0.8-0.9 range as determined by gel permeation chromatography (GPC). Thermal-induced opening of the cycles, made possible by the incorporated alkoxyamine, resulted in a return to the original apparent molecular weight, further supporting the formation of cyclic polymers in the RTA-ATRC reaction. Liquid chromatography-mass spectrometry (LC-MS) provided direct confirmation of the cyclic architecture and the incorporation of the nitroso group into the macrocycle RTA-ATRC cyclizations carried out with faster rates of polymer addition into the redox active solution and/or in the presence of a much larger excess of MNP (up to a 250:1 ratio of MNP:C-Br chain end) still yielded cyclic polymers that contained alkoxyamine functionality.