Publications associées à Measurements of eddy correlation oxygen fluxes in shallow freshwaters: Towards routine applications and analysis

Iron Reduction in Profundal Sediments of Ultraoligotrophic Lake Tahoe under Oxygen-Limited Conditions

Increased periods of bottom water anoxia in deep temperate lakes due to decreasing frequency and depth of water column mixing in a warming climate may result in the reductive dissolution of iron minerals and increased flux of nutrients from the sediment in ...

2023

Spatial Variability of Turbulent Mixing From an Underwater Glider in a Large, Deep, Stratified Lake

Alfred Johny Wüest, Sébastien Lavanchy, Damien Bouffard, Bieito Fernandez Castro, Oscar Rodrigo Sepúlveda Steiner, Alexander Lebaron Forrest

Recent efforts using microstructure turbulence measurements have contributed to our understanding of the overall energy budget in lakes and linkages to vertical fluxes. A paucity of lake-wide turbulence measurements hinders our ability to assess how repres ...

AMER GEOPHYSICAL UNION2023

Electron probing of oxygen-evolving oxide catalysts

Tzu-Hsien Shen

Water splitting is one of the cleanest ways to store energy. The production of hydrogen and oxygen gases can be utilized in fuel cells to generate electricity, power, and heat. In the water splitting process, the oxygen evolution reaction (OER), taking pla ...

EPFL2022

A Cryo-CMOS Oscillator With an Automatic Common-Mode Resonance Calibration for Quantum Computing Applications

Edoardo Charbon, Fabio Sebastiano, Yue Chen

This article presents a 4-to-5 GHz LC oscillator operating at 4.2K for quantum computing applications. The phase noise (PN) specification of the oscillator is derived based on the control fidelity for a single-qubit operation. To reveal the substantial gap ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Structure, Oxygen Content and Electric Properties of Titanium Nitride Electrodes in TiNx/La:HfO2/TiNx Stacks Grown by PEALD on SiO2/Si

Philippe Buffat, Elena Suvorova Buffat

This work reports experimental results of the quantitative determination of oxygen and band gap measurement in the TiNx electrodes in planar TiNx top/La:HfO2/TiNx bottom MIM stacks obtained by plasma enhanced atomic layer deposition on SiO2. Methodological ...

2022

Unraveling the complexity of oxygen reactions on Pt surfaces

Rainer Beck, Ana Gutiérrez González

Platinum (Pt) is a key material in automotive catalytic converters used to clean up the exhaust of the combustion engine. Pt particles in a ceramic matrix serve as an oxidation catalyst to eliminate toxic carbon monoxide (CO) and unburned hydrocarbons (CxH ...

2019

Oxygen diffusion through air–water free surfaces in a pump–turbine operating in condenser mode

François Avellan, Elena Vagnoni, Loïc Andolfatto, Pierre Leroy

The present research aims at understanding the mass transfer of air into water in a reversible pump turbine operating in condenser mode. In particular, the diffusion of oxygen through the water free-surface both in the vaneless gap between the impeller bla ...

2019

Using small-scale measurements to estimate hypolimnetic oxygen depletion in a deep lake

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Low oxygen concentrations in lakes and reservoirs are an ongoing environmental concern, particularly in light of increasing anthropogenic activity and climate change. Oxygen depletion processes in lakes are still not completely understood and a variety of ...

American Society of Limnology and Oceanography2018

Oxygen depletion in Lake Geneva

Robert Vincent Schwefel

Low oxygen concentrations remain a global concern for the ecological health of lakes. High nutrient inputs and climate-induced changes in stratification and mixing are anthropogenic threats which largely impact aquatic oxygen budgets and overall ecosystem ...

EPFL2017

Sequestered Chloroplasts In The Benthic Foraminifer Haynesina Germanica: Cellular Organization, Oxygen Fluxes And Potential Ecological Implications

Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

Haynesina germanica is a coastal benthic foraminifer known to sequester chloroplasts from benthic pennate diatoms. This study investigates its cellular organization, as well as the oxygen consumption and production rates under dark and light conditions. Th ...

2017

In vivo measurement of the tissue oxygenation by time-resolved luminescence spectroscopy of protoporphyrin IX: Strategies to minimize artefacts associated with photoproducts

Georges Wagnières, Veronika Huntosova, Emmanuel Louis Arthur Gerelli

The determination of the oxygen partial pressure (pO(2)) in real time in living biological tissues is of high interest for numerous therapeutics, including photodynamic therapy (PDT) and radiotherapy. The minimally invasive and real-time measurement of the ...

Spie-Int Soc Optical Engineering2017

Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

Anders Meibom, Stéphane Laurent Escrig, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna ...

Public Library of Science2017

In situ core-level and valence-band photoelectron spectroscopy of reactively sputtered tungsten oxide films

Andreas Schueler, Olivia Valérie Charlotte Bouvard, Anna Krammer

In this paper, we study tungsten oxides deposited by reactive magnetron sputtering. The total working pressure during deposition was varied in order to obtain different morphology. The effects on the electronic properties and chemical composition were stud ...

Wiley-Blackwell2016

Effect of PpIX photoproducts formation on pO2 measurement by time-resolved delayed fluorescence spectroscopy of PpIX in solution and in vivo

Georges Wagnières, Matthieu Philippe Emmanuel Zellweger, Veronika Huntosova, Emmanuel Louis Arthur Gerelli

The measurement of Protoporphyrin IX delayed fluorescence lifetime is a minimally invasive method for monitoring the levels of oxygen in cells and tissues. The excitation of Protoporphyrin IX during this measurement can lead to the formation of photoproduc ...

Elsevier Science Sa2016

Measurement-based control of a mechanical oscillator at its thermal decoherence rate

Tobias Kippenberg, Vivishek Sudhir, Nicolas Piro Mastracchio, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson

In real-time quantum feedback protocols(1,2), the record of a continuous measurement is used to stabilize a desired quantum state. Recent years have seen successful applications of these protocols in a variety of well-isolated micro-systems, including micr ...

Nature Publishing Group2015

Improving simulation predictions of wind around buildings using measurements

Didier Vernay

Wind behavior in urban areas is receiving an increasing amount of interest from city planners and architects. In the context of Singapore, knowledge of wind behavior helps to improve building ventilation and, on a larger scale, urban ventilation. Computati ...

EPFL2015

Sediment oxygen uptake in Lake Geneva

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Between 1960 and 1980, the trophic state of Lake Geneva (situated between France and Switzerland) has changed from oligotrophic to eutrophic. Since then, the areal hypolimnetic oxygen demand of 1.31 gm-2 d-1 is now the highest measured in Switzerland and l ...

2014

Time-resolved measurements of suprathermal ion transport induced by intermittent plasma blob-filaments

Ambrogio Fasoli, Ivo Furno, Alexandre Dominique Bovet

Suprathermal ion turbulent transport in magnetized plasmas is generally non-diffusive, ranging from subdiffusive to superdiffusive depending on the interplay of the turbulent structures and the suprathermal ion orbits. Here, we present time-resolved measur ...

American Physical Society2014

Factors affecting the development and dynamics of hypoxia in a large shallow stratified lake: Hourly to seasonal patterns

Damien Bouffard

[1] The examination of hypoxia in the hypolimnion of large lakes traditionally focuses on the assessment of its spatial and temporal extent and its effect on water quality. In Lake Erie, hypoxia typically occurs between July and October in the central basi ...

American Geophysical Union2013

Hypolimnetic Oxygen Depletion in Eutrophic Lakes

Alfred Johny Wüest, Beat Mueller

The oxygen-consuming processes in the hypolimnia of freshwater lakes leading to deep-water anoxia are still not well understood, thereby constraining suitable management concepts. This study presents data obtained from 11 eutrophic lakes and suggests a mod ...

Amer Chemical Soc2012