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Physical insights from the aspect ratio dependence of turbulence in negative triangularity plasmas

In this work, we study the impact of aspect ratio A = R 0 / r (the ratio of major radius R 0 to minor radius r) on the confinement benefits of negative triangularity (NT) plasma shaping. We use high-fidelity flux tube gyrokinetic GENE simulations and consi ...

Iop Publishing Ltd2024

Anisotropic Adaptive Finite Elements for a p-Laplacian Problem

Marco Picasso, Paride Passelli

The p-Laplacian problem -del & sdot; ((mu + |del u|(p-2))del u) = f is considered, where mu is a given positive number. An anisotropic a posteriori residual-based error estimator is presented. The error estimator is shown to be equivalent, up to higher ord ...

Walter De Gruyter Gmbh2024

Re-design of EU DEMO with a low aspect ratio

Hartmut Zohm

The design point that had been chosen for EU DEMO in 2016 is reviewed here and a modification is proposed with a lower aspect ratio. Previously the same aspect ratio, A, was chosen for EU DEMO as in major tokamak experiments including ITER (A = 3.1), and, ...

2024

Adaptive Finite Elements with Large Aspect Ratio. Application to Aluminium Electrolysis

Paride Passelli

The goal of this work is to use anisotropic adaptive finite elements for the numerical simulation of aluminium electrolysis. The anisotropic adaptive criteria are based on a posteriori error estimates derived for simplified problems. First, we consider an ...

EPFL2024

Shafranov shift correction to the Furth-Yoshikawa scaling of tokamak adiabatic compression

Olivier Sauter

In 1970, Furth and Yoshikawa (1970 Phys. Fluids 13 2593-6) introduced the scalings of adiabatic plasma compression. Basically, if the shape of the external plasma boundary and the aspect ratio are preserved during the compression, then the density, kinetic ...

2023

From thin plates to Ahmed bodies: linear and weakly nonlinear stability of rectangular prisms

Edouard Boujo, Giuseppe Antonio Zampogna

We study the stability of laminar wakes past three-dimensional rectangular prisms. The width-to-height ratio is set to W/H = 1.2, while the length-to-height ratio 1/6 < L/H < 3 covers a wide range of geometries from thin plates to elongated Ahmed bodies. F ...

Cambridge University Press2023

Swirling against the forcing: Evidence of stable counterdirected sloshing waves in orbital-shaken reservoirs

François Gallaire, Alessandro Bongarzone, Alice Evelyne Julienne Marcotte

We investigate the response of the free liquid surface in a partially filled circular cylindrical container undergoing a planar elliptic and time-periodic orbit while maintaining fixed its orientation. For small forcing amplitudes and deep liquid layers, w ...

Amer Physical Soc2023

Semiconductor-based device architectures in multimaterial fibers

William Nicolas Duncan Esposito

Semiconductor materials have given rise to today's digital technology and consumer electronics. Widespread adoption is closely linked to the ability to process and integrate them in devices at scale. Where flexibility and large surfaces are required, such ...

EPFL2023

New Developments in Amorphous Silicon Based Microchannel Plates

Christophe Ballif, Nicolas Würsch, Luca Massimiliano Antognini, Samira Alexandra Frey, Mohammad Beygi

Microchannel plates fabricated from hydrogenated amorphous silicon (AMCPs) are a promising alternative to conventional glass microchannel plates. Their main advantages lie in their flexible fabrication processes, allowing for adaptable channel shapes and t ...

2023

Amorphous Silicon Based Microchannel Plates for Time-of-Flight Positron Emission Tomography

Samira Alexandra Frey

Microchannel plates fabricated from hydrogenated amorphous silicon (AMCPs) are a promising alternative to conventional lead glass microchannel plates. Their main advantages lie in their cheaper and more flexible fabrication processes, allowing for adaptabl ...

EPFL2023

Revisiting the role of friction coefficients in granular collapses: confrontation of 3-D non-smooth simulations with experiments

Gauthier Paul Daniel Marie Rousseau

In this paper, transient granular flows are examined both numerically and experimentally. Simulations are performed using the continuous three-dimensional (3-D) granular model introduced in Daviet & Bertails-Descoubes (ACM Trans. Graph., vol. 35, no. 4, 20 ...

Cambridge University Press2023

Nanomechanical resonators with low dissipation for quantum optomechanics

Alberto Beccari

Fields of technology as diverse as microwave filter construction, characterization of material interfaces with atomic precision, and detection of gravitational waves from astronomical sources employ mechanical resonators at their core. The utility of mecha ...

EPFL2023

An Unbiased Method of Measuring the Ratio of Two Data Sets

Jean-Paul Richard Kneib, Huanyuan Shan

In certain cases of astronomical data analysis, the meaningful physical quantity to extract is the ratio R between two data sets. Examples include the lensing ratio, the interloper rate in spectroscopic redshift samples, and the decay rate of gravitational ...

IOP Publishing Ltd2023

High Aspect Ratio Au Microflakes via Gap-Assisted Synthesis

Giulia Tagliabue, Fateme Kiani Shahvandi

Ultrathin and extra-large single-crystalline Au microflakes (Au MFs) have a huge potential in applications ranging from nanophotonics to catalysis. Yet, wet chemical synthesis approaches cannot access this size range due to the proportionality between grow ...

2022

The thermally activated deformation behaviour of single-crystalline microcast aluminium wires

Andreas Mortensen, Léa Deillon, Suzanne Godelieve Alphonsine Verheyden

A microcasting process is used to produce high aspect ratio ( > 30) monocrystalline pure aluminium wires with a diameter between 14 and 115 mu m. The role of thermal activation in the plastic deformation of these microwires is measured by means of (single) ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Effect of Native Oxide on Stress in Silicon Nanowires: Implications for Nanoelectromechanical Systems

Yusuf Leblebici, Zuhal Tasdemir, Mohammad Nasr Esfahani

Understanding the origins of intrinsic stress in Si nanowires (NWs) is crucial for their successful utilization as transducer building blocks in next-generation, miniaturized sensors based on nanoelectromechanical systems (NEMS). With their small size lead ...

AMER CHEMICAL SOC2022

Controlled filamentation instability as a scalable fabrication approach to flexible metamaterials

Fabien Sorin, Pierre-Luc Eloi Piveteau, William Nicolas Duncan Esposito, Louis Marie Philippe Martin-Monier

Long and flexible arrays of nanowires find impactful applications in sensing, photonics, and energy harvesting. Conventional manufacturing relies largely on lithographic methods limited in wafer size, rigidity, and machine write time. Here, we report a sca ...

Nature Portfolio2022

Controlling surface effects in extremely high aspect ratio gold plasmonic electrodes

Olivier Martin, Christian Santschi, Marco Riccardi

Nanofabrication is key to many technological advances, especially the challenge of merging nanophotonics with electronics. Here, we investigate the fabrication process of plasmonic interdigitated gold electrodes having a very high aspect ratio (i.e. long a ...

ELSEVIER2022

Highly Integrated Multi-Material Fibers for Soft Robotics

Fabien Sorin, Stella Andréa Françoise Laperrousaz, Hritwick Banerjee, Andreas Leber, Chaoqun Dong, Nicola Bartolomei, Bastien Schyrr

Soft robots are envisioned as the next generation of safe biomedical devices in minimally invasive procedures. Yet, the difficulty of processing soft materials currently limits the size, aspect-ratio, manufacturing throughput, as well as, the design comple ...

WILEY2022

Conjugate heat transfer in isolated granular clusters with interstitial fluid using lattice Boltzmann method

Mehrdad Kiani Oshtorjani

The conjugate heat transfer in mixtures of a fluid and single granular clusters is studied in this paper using a novel lattice Boltzmann method (LBM) programmed for parallel computation on the graphics processing unit (GPU). The LBM is validated for heat c ...

PERGAMON-ELSEVIER SCIENCE LTD2022