1,721,015 research outputs found
Towards a sub-10nm optical fibre light source
No full textLight sources with sub-10nm spot sizes have a wealth of applications, including optical memories, optical tweezers, SNOM microscopy and photolithography, just to cite a few. Overall, light confinement is limited by diffraction, which can be seen as a direct consequence of Heisenberg's uncertainty principle [1]. Recent results show that "sub-wavelength" light sources can be manufactured using many techniques, including metamaterials and negative refractive index materials [2,3]. Very often these techniques have been proven inefficient, bulky and do not work at short wavelengths. In this paper, light confinement is attained in nanostructured optical fiber tips exploiting surface plasmon polaritons (SPP)
Discussion on “Computing the Trajectory of Free Jets” by T.L. Wahl, K.H. Frizzell and E.A. Cohen
No full textIl principio dello sviluppo sostenibile
No full textIl capitolo analizza il principio dello sviluppo sostenibile, ripercorrendone l'evoluzione dalle origini internazionali fino alla codificazione ad opera del Codice dell'ambiente. Secondo l'Autore il principio incarna la matrice di doverosità del diritto ambientale ed è necessario analizzare il legame che vi è tra principi giuridici ed etica.
Il libro è frutto del lavoro di un gruppo di studiosi che si riunisce periodicamente per discutere dell'evoluzione del diritto amministrativo
Sub-wavelength light confinement in optical fibres and tapers using surface plasmons
No full textLight confinement beyond the diffraction limit is proposed in optical fibres and fibre tapers by exploiting surface plasmons (SPs). To achieve high transmission efficiency, light is converted into SPs at the fibre/taper tip and then converted back into light. Indeed SPs can be confined to dimensions smaller than diffraction limit, but they require stringent conditions for their excitation: the light incidence angle depends on the wavelength (Figure 1a) and it has a strong dependence on the taper diameter (Figure 1b). For this reason fibre/taper nanostructuring needs to be extremely accurate. In this work, optical fibres and fibre tapers (Figure 1c, 1d) have been nanostructured to achieve highly efficient SPs excitation and high transmission efficiency. The effect of different milling shape on transmission has also been analyzed. Transmissivities as high as 7% have been observed
Optical fiber microwires and nanowires manufactured by modified flame brushing technique: properties and applications
No full textThe modified "flame brushing" technique has been used to manufacture microwires and nanowires from both silica and compound glasses. In this paper, the properties of the wires manufactured by this technique are presented. Applications fabricated from microwires are also discussed
Nappe flow over horizontal stepped chutes
No full textStepped chutes have been frequently used since the 1980s in order to take advantage of their dissipation efficiency, aeration characteristics and relative ease of construction. Two basic flow regimes exist for stepped chutes: nappe flow and skimming flow, with the nappe flow having received less attention in comparison to the skimming flow regime. This work suggests a simple iterative method, valid for sub-to-supercritical approach flow conditions, for predicting the basic nappe flow features on a horizontal multi-step structure. The proposed calculation procedure, if applied along the stepped chute, allows us to calculate the flow depth at each step brink and at each nappe impact point, the thickness of the water cushion beneath the nappe, the jet impact length and the energy dissipation rate. For validating the proposed analytical approach, a comparison between experimental and calculated data is also presented
Modelli di simulazione di sistemi di approviggionamento idrico per la definizione di politiche di gestione della domanda
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