Author
Fabio Villa
Other affiliations: University of Bergamo, City University London
Bio: Fabio Villa is an academic researcher from University of Mons. The author has contributed to research in topics: Contact angle & Glacier. The author has an hindex of 10, co-authored 44 publications receiving 643 citations. Previous affiliations of Fabio Villa include University of Bergamo & City University London.
Topics: Contact angle, Glacier, Drop (liquid), Boiling, Beam (structure)
Papers
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TL;DR: In this article, the authors present an experimental study on water drop oblique impacts onto hydrophobic and super-hydrophobic tilted surfaces, with the objective of understanding drop impact dynamics and the conditions for drop rebound on low wetting surfaces.
Abstract: This paper presents an experimental study on water drop oblique impacts onto hydrophobic and superhydrophobic tilted surfaces, with the objective of understanding drop impact dynamics and the conditions for drop rebound on low wetting surfaces. Drop impact experiments were performed with millimetric water drops with Weber numbers in the range 25 < We < 585, using different surfaces with advancing contact angles 111° < θ
A < 160° and receding contact angles 104° < θ
R < 155°. The analysis of oblique impacts onto tilted surfaces led to the definition of six different impact regimes: deposition, rivulet, sliding, rolling, partial rebound, and rebound. For superhydrophobic surfaces, surface tilting generally enhanced drop rebound and shedding from the surface, either by reducing drop rebound time up to 40 % or by allowing drop rebound even when impalement occurred in the vicinity of the impact region. On hydrophobic surfaces, rebound was never observed for tilt angles higher than 45°.
222 citations
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TL;DR: It was found that the receding contact angle is the key wetting parameter that influences drop rebound, along with surface hydrophobicity, and care must be taken when using statically defined wetting parameters to predict the dynamic behavior of a liquid on a solid surface.
Abstract: Data from the literature suggest that the rebound of a drop from a surface can be achieved when the wettability is low, i.e., when contact angles, measured at the triple line (solid–liquid–air), are high. However, no clear criterion exists to predict when a drop will rebound from a surface and which is the key wetting parameter to govern drop rebound (e.g., the “equilibrium” contact angle, θeq, the advancing and the receding contact angles, θA and θR, respectively, the contact angle hysteresis, Δθ, or any combination of these parameters). To clarify the conditions for drop rebound, we conducted experimental tests on different dry solid surfaces with variable wettability, from hydrophobic to superhydrophobic surfaces, with advancing contact angles 108° < θA < 169° and receding contact angles 89° < θR < 161°. It was found that the receding contact angle is the key wetting parameter that influences drop rebound, along with surface hydrophobicity: for the investigated impact conditions (drop diameter 2.4 < D0...
137 citations
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TL;DR: The EuPRAXIA project aims at the construction of an innovative electron accelerator using laser-and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators as discussed by the authors.
Abstract: This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years.
77 citations
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TL;DR: In this paper, the authors present a large-scale visualization and large-dydydy simulation of cavitation inside the apparatus used for surface erosion acceleration tests and material response monitoring.
75 citations
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TL;DR: In this article, an advanced Source of up to 20 MeV Gamma Rays based on Compton back-scattering is described, which is a collision of an intense high power laser beam and a high brightness electron beam with maximum kinetic energy of about 720 MeV.
Abstract: The machine described in this document is an advanced Source of up to 20 MeV Gamma Rays based on Compton back-scattering, i.e. collision of an intense high power laser beam and a high brightness electron beam with maximum kinetic energy of about 720 MeV. Fully equipped with collimation and characterization systems, in order to generate, form and fully measure the physical characteristics of the produced Gamma Ray beam. The quality, i.e. phase space density, of the two colliding beams will be such that the emitted Gamma ray beam is characterized by energy tunability, spectral density, bandwidth, polarization, divergence and brilliance compatible with the requested performances of the ELI-NP user facility, to be built in Romania as the Nuclear Physics oriented Pillar of the European Extreme Light Infrastructure. This document illustrates the Technical Design finally produced by the EuroGammaS Collaboration, after a thorough investigation of the machine expected performances within the constraints imposed by the ELI-NP tender for the Gamma Beam System (ELI-NP-GBS), in terms of available budget, deadlines for machine completion and performance achievement, compatibility with lay-out and characteristics of the planned civil engineering.
61 citations
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01 Sep 1994
TL;DR: In this article, the authors present a review of Charged Particle Dynamics and Focusing Systems without Space Charge, including Linear Beam Optics with Space Charge and Self-Consistent Theory of Beams.
Abstract: Review of Charged Particle Dynamics. Beam Optics and Focusing Systems Without Space Charge. Linear Beam Optics with Space Charge. Self-Consistent Theory of Beams. Emittance Variation. Beam Physics Research from 1993 to 2007. Appendices. List of Frequently Used Symbols. Bibliography. Index.
1,311 citations
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Ankara University1, Middle East Technical University2, Laboratoire d'Annecy-le-Vieux de physique des particules3, National Technical University of Athens4, University of Basel5, Fermilab6, Tsinghua University7, Lawrence Berkeley National Laboratory8, University of Bern9, Boston University10, University of Sussex11, Massachusetts Institute of Technology12, University of Chicago13, University of Copenhagen14, Durham University15, Michigan State University16, University of Edinburgh17, University of Freiburg18, University of Florida19, Gangneung–Wonju National University20, CERN21, University of Geneva22, University of Iowa23, Cornell University24, University of Johannesburg25, University of California, San Diego26, King's College London27, University College London28, University of Wisconsin-Madison29, University of Manchester30, Instituto Politécnico Nacional31, Instituto Tecnológico de Puebla32, University of Milano-Bicocca33, University of Murcia34, Thomas Jefferson National Accelerator Facility35, University of Oklahoma36, Budker Institute of Nuclear Physics37, Centre national de la recherche scientifique38, University of Pavia39, Hellenic Open University40, Rutgers University41, University of Pittsburgh42, Sapienza University of Rome43, Recep Tayyip Erdoğan University44, University of Southampton45, KEK46, University of Udine47, Spanish National Research Council48, Cockcroft Institute49
TL;DR: In this article, the authors present a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study, and present a combination of TLEp and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market.
Abstract: The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e+e- collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for top-quark, Higgs boson, W and Z studies, accommodates multiple detectors, and can reach energies up to the t-tbar threshold and beyond. It will enable measurements of the Higgs boson properties and of Electroweak Symmetry-Breaking (EWSB) parameters with unequalled precision, offering exploration of physics beyond the Standard Model in the multi-TeV range. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. Altogether, the combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market. This paper presents a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study.
445 citations
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TL;DR: A method, which utilizes the large difference in ionization potentials between successive ionization states of trace atoms, for injecting electrons into a laser-driven wakefield is presented, and a mixture of helium and trace amounts of nitrogen gas was used.
Abstract: A method, which utilizes the large difference in ionization potentials between successive ionization states of trace atoms, for injecting electrons into a laser-driven wakefield is presented. Here a mixture of helium and trace amounts of nitrogen gas was used. Electrons from the K shell of nitrogen were tunnel ionized near the peak of the laser pulse and were injected into and trapped by the wake created by electrons from majority helium atoms and the L shell of nitrogen. The spectrum of the accelerated electrons, the threshold intensity at which trapping occurs, the forward transmitted laser spectrum, and the beam divergence are all consistent with this injection process. The experimental measurements are supported by theory and 3D OSIRIS simulations.
382 citations
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TL;DR: In this paper, the authors present a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study, and present a combination of TLEp and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market.
Abstract: The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e+e- collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for top-quark, Higgs boson, W and Z studies, accommodates multiple detectors, and can reach energies up to the t-tbar threshold and beyond. It will enable measurements of the Higgs boson properties and of Electroweak Symmetry-Breaking (EWSB) parameters with unequalled precision, offering exploration of physics beyond the Standard Model in the multi-TeV range. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. Altogether, the combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market. This paper presents a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study.
341 citations