Publications associées à Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

SPEEDING UP KRYLOV SUBSPACE METHODS FOR COMPUTING f(A)b VIA RANDOMIZATION

This work is concerned with the computation of the action of a matrix function f(A), such as the matrix exponential or the matrix square root, on a vector b. For a general matrix A, this can be done by computing the compression of A onto a suitable Krylov ...

Siam Publications2024

Randomized low-rank approximation and its applications

Ulf David Persson

In this thesis we will present and analyze randomized algorithms for numerical linear algebra problems. An important theme in this thesis is randomized low-rank approximation. In particular, we will study randomized low-rank approximation of matrix functio ...

EPFL2024

Thermal conductivity of Li 3 PS 4 solid electrolytes with ab initio accuracy

Michele Ceriotti, Federico Grasselli

The vast amount of computational studies on electrical conduction in solid-state electrolytes is not mirrored by comparable efforts addressing thermal conduction, which has been scarcely investigated despite its relevance to thermal management and (over)he ...

Amer Physical Soc2024

Innovative thermophysical characterization of an ATF composite cladding: the case of silicon carbide

Andrea Cavaliere

Nuclear power is a powerful technology that plays an important role in the fight against climate change, and research is continuously engaged in studies that could further improve its safety. After the Fukushima accident, Accident Tolerant Fuels research h ...

EPFL2024

Duality and bicrystals on infinite binary matrices

Thomas Gerber

The set of finite binary matrices of a given size is known to carry a finite type AA bicrystal structure. We first review this classical construction, explain how it yields a short proof of the equality between Kostka polynomials and one-dimensional sums t ...

2023

A mixed precision LOBPCG algorithm

Daniel Kressner, Meiyue Shao, Yuxin Ma

The locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm is a popular approach for computing a few smallest eigenvalues and the corresponding eigenvectors of a large Hermitian positive definite matrix A. In this work, we propose a mix ...

SPRINGER2023

A model for the consolidation of hybrid textiles considering air entrapment, dissolution and diffusion

Véronique Michaud, Vincent Werlen, Christian Rytka

A new model is proposed for the consolidation of hybrid textiles, in which air entrapment and dissolution are considered. One of the key parameters is tow permeability, which is described by the analytical model of Gebart and validated at very high fibre v ...

ELSEVIER SCI LTD2023

Preconditioning techniques for generalized Sylvester matrix equations

Yannis Dirk Voet

Sylvester matrix equations are ubiquitous in scientific computing. However, few solution techniques exist for their generalized multiterm version, as they now arise in an increasingly large number of applications. In this work, we consider algebraic parame ...

2023

Understanding and mitigating resistive losses in fired passivating contacts: role of the interfaces and optimization of the thermal budget

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Luca Massimiliano Antognini, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset

This work presents a study of p-type passivating contacts based on SiCx formed via a rapid thermal processing (RTP) step, using conditions compatible with the firing used to sinter screen-printed metallization pastes in industry. The contributions of the t ...

Elsevier2023

Layered metals as polarized transparent conductors

Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo, Maja Deborah Bachmann

The quest to improve transparent conductors balances two key goals: increasing electrical conductivity and increasing optical transparency. To improve both simultaneously is hindered by the physical limitation that good metals with high electrical conducti ...

Nature Portfolio2023

AC loss and electrical resistance of the RW3 diffusion-bonded joint

Vincenzo D'Auria

For the European DEMO fusion reactor, several options of the Toroidal Field (TF) coil design were proposed. The winding of the TF coil option 1 is based on React&Wind (RW), Nb3Sn, graded conductors in order to optimize the amount of superconductor accordin ...

2023

Using continuous electrical conductivity measurements to derive major solute concentrations in karst systems

Paolo Benettin

Hydrochemical data of karst springs provide valuable insights into the internal hydrodynamical functioning of karst systems and support model structure identification. However, the collection of high-frequency time series of major solute species is limited ...

WILEY2023

Interlocking modular microfluidic cooling substrates for future high energy physics experiments

Massimo Angeletti

In high energy physics, semiconductor-based sensors are widely used in particle tracking applications. These sensors are typically glued on low-mass cooling substrates, which guarantee the correct thermal management and, at the same time, minimise their in ...

EPFL2023

Multiphysics model for assessing photoelectrochemical phenomena under concentrated irradiation

Sophia Haussener, Isaac Thomas Holmes-Gentle, Franky Esteban Bedoya Lora

A multiphysics model was developed for a photoelectrochemical (PEC) cell at the device level to simulate water splitting operating under concentrated irradiation (between 50 to 600 kW m−2). The 2D model couples charge, heat, mass, photon, and momentum tran ...

2023

Fast deterministic and randomized algorithms for low-rank approximation, matrix functions, and trace estimation

Alice Cortinovis

In this thesis we propose and analyze algorithms for some numerical linear algebra tasks: finding low-rank approximations of matrices, computing matrix functions, and estimating the trace of matrices. In the first part, we consider algorithms for building ...

EPFL2022

Drops: Controlled crystallization of organic crystals and their use as matrix materials for encapsulation of volatiles

Aysu Ceren Okur

Encapsulation techniques open up new possibilities to control the kinetics and location of the release of active ingredients. Despite the progresses achieved to obtain a better control over the dimensions and composition of the capsules, the encapsulation ...

EPFL2022

DIVIDE-AND-CONQUER METHODS FOR FUNCTIONS OF MATRICES WITH BANDED OR HIERARCHICAL LOW-RANK STRUCTURE\ast

Daniel Kressner, Stefano Massei, Alice Cortinovis

This work is concerned with approximating matrix functions for banded matrices, hierarchically semiseparable matrices, and related structures. We develop a new divide-and-conquer method based on (rational) Krylov subspace methods for performing low-rank up ...

SIAM PUBLICATIONS2022

IMPROVED VARIANTS OF THE HUTCH plus plus ALGORITHM FOR TRACE ESTIMATION

Daniel Kressner, Alice Cortinovis, Ulf David Persson

This paper is concerned with two improved variants of the Hutch++ algorithm for estimating the trace of a square matrix, implicitly given through matrix-vector products. Hutch++ combines randomized low-rank approximation in a first phase with stochastic tr ...

SIAM PUBLICATIONS2022

Application of Copper Thermal Spraying for Electrical Joints between Superconducting Nb3Sn Cables

Pierluigi Bruzzone, Vincenzo D'Auria

This manuscript reports on the application of copper thermal spraying in the manufacturing process of an electrical connection between Nb3Sn cables for superconducting magnets of fusion reactors. The joint is realized through diffusion bonding of the spray ...

MDPI2022

Iterative refinement of Schur decompositions

Daniel Kressner, Zvonimir Bujanovic

The Schur decomposition of a square matrix A is an important intermediate step of state-of-the-art numerical algorithms for addressing eigenvalue problems, matrix functions, and matrix equations. This work is concerned with the following task: Compute a (m ...

SPRINGER2023