In-situ OH kinetics study providing an indicator for ozone formation limitation

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A strong societal and political drive is motivating the development and optimization of novel energy conversion and storage systems for decarbonization. The successful implementation of solid state devices such as fuel cells and secondary batteries depends, however, on achieving ambitious targets in terms of performance, reliability and cost competitiveness. Research and technology are addressing these needs through a holistic approach including exploration of new materials and nano

Abinit is a widely used scientific software package implementing density functional theory and many related functionalities for excited states and response properties. This paper presents the novel features and capabilities, both technical and scientific, which have been implemented over the past 5 years. This evolution occurred in the context of evolving hardware platforms, high-throughput calculation campaigns, and the growing use of machine learning to predict properties based on databases of first-princ

With over 1.6 billion vehicles worldwide, the combustion of fossil fuels is a major source of particulate matter (PM) and trace gases, which significantly contribute to air pollution, climate change and cause health burden. Heavy-duty vehicles (HDVs) constitute a small fraction of the global vehicle population but account for a disproportionately large share of total emissions when compared with light-duty vehicles (LDVs). However, uncertainty remains about which vehicle type contribute most to the emission

The assessment of the risk maps for the seismic vulnerability at large scale is based on the vulnerability of each building. In order to determine these vulnerabilities, it is first required to assign to each building its construction class. The construction class is needed to define the seismic behavior of the building. Since the structures have been built in different times, this construction classes are different between them, and their vulnerability values have been pre-defined in order to simplify the

Wear of materials plays a key role in the durability of manifactured objects and it has thus an economical importance in our society. In spite of the efforts, a unified picture of the underlying physics of the phenomenon is still far from being reached, because of the numerous mechanisms and processes that constitute the complexity of wear. Moving one step closer to the understanding of the physics of wear would mean enhancing our understanding of all the related fields that it affects, like friction and co

Simulating crack nucleation and propagation remains a challenging problematic because of the complexity of crack patterns observed in fracture mechanics experiments. Whereas some numerical methods aim at explicitly tracking the crack front evolution, an interesting alternative is offered by continuous approaches of brittle fracture which consist in representing the crack topology using a continuous field varying from 0 (sound material) to 1 (fully cracked material) across an internal length scale. This « ph

The Nucleus Pulposus (NP) is an avascular tissue that may be subject to temperature increase. Indeed, since the NP is not perfused by the cardio-vascular system, it implies that heat cannot be convected from it. The sources of heat could be either external due to the musculature that surrounded the spine, or internal due to viscous dissipations. The overall goal of the project is to characterize heat transfer in the intervertebral disc (IVD). For that purpose, the student will asked to develop a system that

The UV-curable adhesive NOA81 (Norland Optical Adhesive) is a promising liquid photopolymer for low-cost microfluidic chip production. Different fabrication methods for NOA81 are suggested [1,2]. However, optical characterization for fluorescent based detection systems is missing. We present a comparison of fluorescent emissionspectra of various NOA types as well as the time evolution of the spectra of the most promising one - NOA81. We report on a simple rapid prototyping technique to produce chips for flu

In the SLS process, pulsed lasers are mostly used. Since only the surface of the powder particles is molten, consolidation can be achieved at much lower average power. Liquid bridges appear between the powder particles and are responsible for the bonding. The mechanical properties of the final part depend of the shape of these bonds. The goal of this study is to understand how the evolution of the liquid bridges (also called necks) is influenced by the laser parameters.

Interface in Architecture - Norwegian Association of Architects Conference Presentation + Panel moderator: Norwegian University of Science and Technology This presentation showed the work of the lapa: the research and teaching projects accomplished over the last 5 years, and discussed the evolution of methods and technologies at the EPFL. Then, as panel moderator, directed discussion on the issues of technology in architecture, with specific focus on architectural production in the wood industry and product

In this paper, we introduce a self-assembling and self-organizing artifact, called a swarm-bot, composed of a swarm of s-bots, mobile robots with the ability to connect to and to disconnect from each other. We discuss the challenges involved in controlling a swarm-bot and address the problem of synthesizing controllers for the swarm-bot using artificial evolution. Specifically, we study aggregation and coordinated motion of the swarm-bot using a physics-based simulation of the system. Experiments, using a s

Experiments are conducted on JET to assess the potential for plasma diagnostic spectroscopy and mode stability control, of Alfven eigenmodes (AEs), excited by external antennas and by energetic particles. Information on the time evolution of the nonmonotonic current profile in advanced scenarios can be obtained from the frequency and mode number. of AEs driven by energetic particles. The appearance of a rational surface associated with a minimum value in the safety factor profile can be inferred with a time

The paper presents a research 1that aims to develop a methodology that supports the elaboration and the optimisation of long term maintenance and renewal policies for railway infrastructure (strategic planning level, up to 20 years). The elaboration process takes the capacity, in other words the costs of track possessions, into account. The developed methodology is divided into two steps: the optimal track possession estimation and the maintenance and renewal policy elaboration. A long term maintenance and

Experiments are conducted on the JET tokamak to demonstrate the diagnostic potential of Magneto-Hydro-Dynamics (MHD) spectroscopy, for the plasma bulk and its suprathennal components, using Alfven eigenmodes (AEs) excited by external antennas and by energetic particles. The measurements of AE frequencies and mode numbers give information on the bulk plasma. Improved equilibrium reconstruction, in particular in. terms of radial profiles of density and safety factor, is possible from the comparison between th

A complete set-up for local annealing of Shape Memory Alloys (SMA) is proposed. Such alloys, when plastically deformed at a given low temperature, have the ability to recover a previously memorised shape simply by heating up to a higher temperature. They find more and more applications in the fields of robotics and micro engineering. There is a tremendous advantage in using local annealing because this process can produce monolithic parts, which have different mechanical behavior at different location of th

This paper is concerned with artificial evolution of neuro-controllers with adaptive synapses for autonomous mobile robots. The method consists of encoding on the genotype a set of local modification rules that synapses obey while the robot freely moves in the environment [2]. The synaptic weights are not encoded on the genotype. In the experiments presented here, a "behavior-based fitness" function gives reproductive advantage to robots that can solve a sequential task. The results show that evolutionary a

Transient measurement techniques were applied to the kinetic investigation of the reaction mechanism of CO2 methanation, using diffuse-reflectance IR spectroscopy and mass spectrometry. The coupled information of the surface intermediates and the time evolution of the gas-phase components leads to accurate identification of spectator species on the surface. Reaction intermediates (e.g., CO and formates) were identified. The former is a key intermediate, and its hydrogenation leads to methane formation. The

Single-pass Raman cells pumped by either a quadrupled Nd:YAG (266-nm) laser or a KrF excimer laser are studied. The Raman-active gases comprise H2, D2, or CH4, as well as a mixt. of them, with the addn. of He, Ne, or Ar. A parametric study, in which the Stokes conversion efficiency and the beam quality (M2) were measured, was made. The first Stokes efficiency increases and all the Stokes thresholds decrease with an increase in the lens focal length or the M2 parameter of the pump beam. The quality of the St

A model which takes into account the main phenomena occurring during the laser-cladding process is proposed. For a given laser power, beam radius, powder jet geometry, and clad height, this model evaluates two other processing parameters, namely, the laser-beam velocity and the powder feed rate. It considers the interactions between the powder particles, the laser beam, and the molten pool. The laser power reaching the surface of the workpiece is estimated and, assuming this power is used to remelt the subs

Periodic operation was applied to the CO2 methanation reaction at 383 K on 2% Ru/TiO2. A continuous feed recycle reactor combined with a diffuse reflectance infrared cell and a mass spectrometer allowed to follow simultaneously the gas phase CO2 and CH4 as well as the adsorbed species (CO)a and (formate)a. Experiments consisting of periodic variations of CO2 in the hydrogen feed showed response curves with maxima/minima shifted in time in the sequence CO2, (formate)a --> (CO)a --> CH4. Similar delays measur

In-situ OH kinetics study providing an indicator for ozone formation limitation

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Roadmap on advanced and / real-time characterisation of solid state materials and devices for energy applications

Abinit 2025: New capabilities for the predictive modeling of solids and nanomaterials

Emission Factors of Primary Pollutants from a Real-world Tunnel Measurement

Vulnérabilité sismique à grande échelle de la ville de Lausanne

Fractal surfaces in adhesive wear processes

Variational phase field model for dynamic brittle fracture

Heat transfer in Interverterbral Discs (IVDs)

Microfluidic devices made of UV-curable glue (NOA81) for fluorescence detection based applications

Influence of the process parameters on the liquid bridges between particles in SLS

Interface in Architecture

Evolving Self-Organizing Behaviors for a Swarm-bot

Diagnosis and study of Alfven eigenmodes stability in JET (invited)

Strategic maintenance and renewal policy of a railway corridors, taking into account the value of capacity

MHD spectroscopy

Local annealing of shape memory alloys using laser scanning and computer vision

Evolution of Adaptive-Synapse Controllers

In-situ surface and gas phase analysis for kinetic studies under transient conditions. The catalytic hydrogenation of CO2

Experimental investigation of high-power single-pass Raman shifters in the ultraviolet with Nd:YAG and KrF lasers

A Simple but Realistic Model for Laser Cladding

Periodic operation applied to kinetic studies of CO2-methanation