Publications related to High Thermal Conductivity in Short-Period Superlattices

Unearthing the foundational role of anharmonicity in heat transport in glasses

The time-honored Allen -Feldman theory of heat transport in glasses is generally assumed to predict a finite value for the thermal conductivity, even if it neglects the anharmonic broadening of vibrational normal modes. We demonstrate that the harmonic app ...

Amer Physical Soc2024

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

Thermal transport of glasses via machine learning driven simulations

Federico Grasselli

Accessing the thermal transport properties of glasses is a major issue for the design of production strategies of glass industry, as well as for the plethora of applications and devices where glasses are employed. From the computational standpoint, the che ...

Frontiers Media Sa2024

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

Experimental study of the hydrodynamic and thermal performances of ventilated wall structures

Mohammad Rahiminejad, Dolaana Khovalyg

The presence of a ventilated air gap behind the external cladding in a building envelope is known to have a tangible contribution to the overall performance of the wall assembly. In the present study, the hydrodynamic and thermal performances of ventilated ...

2023

Thermal management for gas lubricated, high-speed turbomachinery

Jürg Alexander Schiffmann, Luis Eric Olmedo Ocampo, Wei Liu, Wanhui Liu

High-speed turbomachinery is commonly designed to achieve high power densities. Limited space for active cooling results in a challenging thermal management. A thermal modeling approach leveraging modern declarative programming capabilities is presented, y ...

2023

Advancing efficiency and reliability in thermal analysis of laser powder-bed fusion

Christian Leinenbach, Thomas Mayer, Rafal Wróbel

In laser based powder-bed fusion of metals (PBF-LB/M), parts are fabricated by melting layers of powder using a high-intensity laser beam. During this process, the material is exposed to rapid cooling rates and intense thermal gradients, which are the unde ...

2023

A hybrid Selective Laser Sintering based process for the additive manufacturing of architectured composites

Erwan Philippe Guenier

Additive Manufacturing also commonly referred as 3D printing has been given a lot of interest lately. Market is growing exponentially and the aim for obtaining more complex and ready-to use parts is emerging. All the 3D printing processes consist in buildi ...

EPFL2023

Machine-learning the electronic density of states: electronic properties without quantum mechanics

Chiheb Ben Mahmoud

The electronic density of states (DOS) quantifies the distribution of the energy levels that can be occupied by electrons in a quasiparticle picture and is central to modern electronic structure theory. It also underpins the computation and interpretation ...

EPFL2023

Effect of a temperature gradient on the screening properties of ionic fluids

Andrea Grisafi, Federico Grasselli

The electrostatic screening properties of ionic fluids are of paramount importance in countless physical processes. Yet the screening behavior of ionic conductors out of thermal equilibrium has to date mainly been studied in the context of thermoelectric p ...

AMER PHYSICAL SOC2023

Wigner Formulation of Thermal Transport in Solids

Nicola Marzari, Michele Simoncelli

Two different heat-transport mechanisms are discussed in solids. In crystals, heat carriers propagate and scatter particlelike as described by Peierls's formulation of the Boltzmann transport equation for phonon wave packets. In glasses, instead, carriers ...

American Physical Society2022

Conductive Heat Transfer in Partially Saturated Gas Diffusion Layers with Evaporative Cooling

Sophia Haussener, Mirco Magnini, Felix N. Büchi

Heat transport is an important, though often neglected function of gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells. Thermal conductivity is a key property, especially in partially water saturated GDLs and when the phase change of wat ...

2022

Many-body Green?s function approach to lattice thermal transport

Nicola Marzari, Michele Simoncelli

Recent progress in understanding thermal transport in complex crystals has highlighted the prominent role of heat conduction mediated by interband tunneling processes, which emerge between overlapping phonon bands (i.e., with energy differences smaller tha ...

AMER PHYSICAL SOC2022

Near-junction microfluidic cooling for high power-density GaN-on-Si electronics: A wafer, device, packaging, and system-level investigation

Remco Franciscus Peter van Erp

Electrification of the energy section, from generation to end-use, plays an essential role in reducing global CO2 emission. Innovations in power electronics are required to increase conversion efficiency and power density. Gallium nitride (GaN) transistors ...

EPFL2022

Measuring the effective thermal resistance of ventilated air-spaces behind common wall assemblies: Theoretical uncertainty analysis and recommendations for the hot box method modifications (ASHRAE 1759-RP)

Mohammad Rahiminejad, Dolaana Khovalyg

A well-designed ventilated wall that incorporates air-space behind cladding can reduce energy use for conditioning buildings by adding a thermally resistive layer. The scarcity of thermal performance data and standardized test methods is a particular barri ...

2022

Multiscale microshaping of functionally graded polymer-derived SiCN ceramics

Lorenz Hagelüken

Polymer-derived ceramics (PDCs) exhibit excellent properties and are compatible with many shaping techniques due to the liquid character of the preceramic polymers (PCPs). Furthermore, their properties are adjustable by modifying the precursor composition ...

EPFL2022

Numerical and experimental study of the dynamic thermal resistance of ventilated air-spaces behind passive and active façades

Mohammad Rahiminejad, Dolaana Khovalyg

The variation of the thermo-hydrodynamic behavior of the airflow in the ventilated cavity behind external claddings in a wall structure could potentially affect the overall thermal resistance of the entire structure. Although the impact of an enclosed air- ...

2022

Microchannel cooling for the LHCb VELO Upgrade I

Alessandro Mapelli, Giulia Romagnoli, Victor Coco

The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase CO2 for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale applic ...

ELSEVIER2022

Impact of the ventilated air-space behind traditional (passive) and BIPV (active) façades on the thermo-hydrodynamic performance of the building wall structures

Mohammad Rahiminejad

For many decades, ventilated cavities in wall assemblies of buildings have been essential for creating moisture-resilient constructions by allowing airflow within the air gap to promote drying. In addition to that, the airflow in the cavity can contribute ...

EPFL2022