Search results for "Linear"
showing 10 items of 7165 documents
Analytical Prediction of the Flexural Response of External RC Joints with Smooth Rebars
2018
Nel presente lavoro viene presentato un modello analitico in forma chiusa in grado di riprodurre la risposta flessionale monotonica di nodi esterni trave-colonna in c.a. con armature lisce. La colonna viene sottoposta a carico verti-cale costante e la trave ad una forza laterale crescente monotonicamente applicata all’estremità. Il modello si basa sul comportamen-to flessionale di trave e colonna adottando un modello di cerniera plasticità concentrata che include lo scorrimento delle armature della trave. Si assume un dominio sforzo normale-momento bilineare semplificato da cui viene derivato il momento ultimo associato alla forza assiale di progetto. Per il nodo viene adottato un modello c…
Opto-thermally controlled beam steering in nonlinear all-dielectric metastructures
2021
Reconfigurable metasurfaces have recently gained a lot of attention in applications such as adaptive meta-lenses, hyperspectral imaging and optical modulation. This kind of metastructure can be obtained by an external control signal, enabling us to dynamically manipulate the electromagnetic radiation. Here, we theoretically propose an AlGaAs device to control the second harmonic generation (SHG) emission at nanoscale upon optimized optical heating. The asymmetric shape of the used meta-atom is selected to guarantee a predominant second harmonic (SH) emission towards the normal direction. The proposed structure is concurrently excited by a pump beam at a fundamental wavelength of 1540 nm and…
Multi-Module vs. Single-Module concept: Comparison of thermomechanical performances for the DEMO Water-Cooled Lithium Lead breeding blanket
2018
Abstract Within the framework of EUROfusion R&D activity an intense research campaign has been performed at the University of Palermo, in close cooperation with ENEA labs and KIT, in order to compare the thermomechanical performances of the Back Supporting Structure (BSS) of Multi-Module and Single-Module concepts of DEMO Water-Cooled Lithium Lead breeding blanket (WCLL). To this purpose, detailed 3D models of the DEMO WCLL right inboard and central outboard segments, including detailed BSS and simplified First Wall and structures according to the two concepts, have been set-up. The study has been performed considering the Normal Operation and Central Major Disruption steady state loading s…
Modelling of Reflectance Spectra of Skin Phototypes III
2011
In dermatology, study of human skin colour is related to skin phototype (SPT) in which the Fitzpatrick's scale is the most used skin photo type classification. Assessment of skin response to UV for various reasons plays an important role in dermatology. This is however not easy to be performed because of two reasons. Firstly, skin areas may have different skin tone resulting in different reflectance spectra and secondly, different modalities may produce different reflectance spectra. We hypothesize that the underlying pattern of reflectance spectra must be similar regardless of the modalities use and the skin areas where it is obtained, for a particular person. An observational clinical stu…
Simulation of the relative atomic populations of elements 1 ≤ Z ≤89 following charge exchange tested with collinear resonance ionization spectroscopy…
2019
© 2019 The Authors Calculations of the neutralisation cross-section and relative population of atomic states were performed for ions beams (1 ≤ Z ≤ 89) at 5 and 40 keV incident on free sodium and potassium atoms. To test the validity of the calculations, the population distribution of indium ions incident on a vapour of sodium was measured at an intermediate energy of 20 keV. The relative populations of the 5s 2 5p 2 P 1/2 and 5s 2 5p 2 P 3/2 states in indium were measured using collinear resonance ionization spectroscopy and found to be consistent with the calculations. Charge exchange contributions to high-resolution lineshapes were also investigated and found to be reproduced by the calc…
Friction based Solid State Welding Techniques for Transportation Industry Applications
2014
Abstract Solid bonding based processes represent an effective solution in terms of both joints mechanical performances and sustainability. In the last years, both the academic and the industrial researchers focused their work on two solid-state processes: Friction Stir Welding (FSW) and Linear Friction Welding (LFW). The former, patented in 1991 by TWI, is used to weld sheet metal in different joint morphologies, i.e. butt, lap T and 3D joints. The latter has been known for several years, but a growing interest is observed in the last years due to the enhancement of the welding machines performances. LFW, used to join bulk components, is particularly suited for aeronautical and aerospace ap…
Rippling of two-dimensional materials by line defects
2020
Two-dimensional materials and their mechanical properties are known to be profoundly affected by rippling deformations. However, although ripples are fairly well understood, less is known about their origin and controlled modification. Here, motivated by recent reports of laser-controlled creation of line defects in graphene, we investigate how line defects could be used to control rippling in graphene and other two-dimensional materials. By sequential multi-scale coupling of density-functional tight-binding and continuum elasticity simulations, we quantify the amount of rippling when the number and the cumulative length of the line defects increase. Simulations show that elastic sheets wit…
Stable proton exchanged waveguides in Lithium Tantalate
2008
alpha, beta(1), and kappa(2) phases are investigated for planar waveguide fabrication by proton exchange in congruent lithium tantalate. The effective indices of planar waveguide eigenmodes were monitored over time, revealing that the exchange process induces aging instabilities in all phases except alpha.
Time‐Domain Integration of Broadband Terahertz Pulses in a Tapered Two‐Wire Waveguide
2021
In this work, the time-domain integration of broadband terahertz (THz) pulses via a tapered two-wire waveguide (TTWWG) is reported. Such a guiding structure consists of two metallic wires separated by a variable air gap that shrinks down to a subwavelength size as the movement takes from the waveguide input to its output. It is shown that while an input THz pulse propagates toward the subwavelength output gap, it is reshaped into its first-order time integral waveform. In order to prove the TTWWG time integration functionality, the THz pulse is detected directly within the output gap of the waveguide, so as to prevent the outcoupling diffraction from altering the shape of the time-integrate…
Universality for the breakup of invariant tori in Hamiltonian flows
1998
In this article, we describe a new renormalization-group scheme for analyzing the breakup of invariant tori for Hamiltonian systems with two degrees of freedom. The transformation, which acts on Hamiltonians that are quadratic in the action variables, combines a rescaling of phase space and a partial elimination of irrelevant (non-resonant) frequencies. It is implemented numerically for the case applying to golden invariant tori. We find a nontrivial fixed point and compute the corresponding scaling and critical indices. If one compares flows to maps in the canonical way, our results are consistent with existing data on the breakup of golden invariant circles for area-preserving maps.