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Concept

Chlorofluorocarbure

Publications associées (23)

Modelling the coupled mercury-halogen-ozone cycle in the central Arctic during spring

Julia Schmale, Ivo Fabio Beck, Hélène Paule Angot

Near-surface mercury and ozone depletion events occur in the lowest part of the atmosphere during Arctic spring. Mercury depletion is the first step in a process that transforms long-lived elemental mercury to more reactive forms within the Arctic that are ...

2023

Temporary pause in the growth of atmospheric ethane and propane in 2015–2018

Hélène Paule Angot, Ilann Ernest Valentin Bourgeois

Atmospheric non-methane hydrocarbons (NMHCs) play an important role in the formation of secondary organic aerosols and ozone. After a multidecadal global decline in atmospheric mole fractions of ethane and propane – the most abundant atmospheric NMHCs – pr ...

Copernicus Publications2021

Ozone Initiates Human-Derived Emission of Nanocluster Aerosols

Dusan Licina, Shen Yang

Nanocluster aerosols (NCAs, particles

AMER CHEMICAL SOC2021

Engaging 1-Alkynyl Triazenes in Transition Metal-Catalyzed and Fluorinative Transformations

Jin Fay Tan

Triazenes have garnered great attention for their anti-cancer properties and versatility in organic chemistry. Recently, a novel synthesis of 1-alkynyl triazenes was reported. This thesis describes the compatibility, reactivity and applications of 1-alkyny ...

EPFL2021

Constraining the response factors of an extractive electrospray ionization mass spectrometer for near-molecular aerosol speciation

Julia Schmale

Online characterization of aerosol composition at the near-molecular level is key to understanding chemical reaction mechanisms, kinetics, and sources under various atmospheric conditions. The recently developed extractive electrospray ionization time-of-f ...

2021

The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results

Dusan Licina, Shen Yang

With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and ...

WILEY2020

Temporal and spatial analysis of ozone concentrations in Europe based on timescale decomposition and a multi-clustering approach

Satoshi Takahama, Eirini Boleti

Air quality measures that were implemented in Europe in the 1990s resulted in reductions of ozone precursor concentrations. In this study, the effect of these reductions on ozone is investigated by analyzing surface measurements of this pollutant for the t ...

Copernicus Publications2020

Statistical methods for accounting and understanding ozone trends derived from observations

Eirini Boleti

Emissions of ozone precursors have been regulated in Europe since around 1990 with air quality control measures, which resulted in reductions of nitrogen oxides and volatile organic compounds concentrations. In order to understand how these measures have a ...

EPFL2020

Microscale physico-chemical interactions between hydrodynamically confined liquids and immersed biological surfaces

David Philipp Taylor

In contrast to conventional microfluidics, where liquids are typically manipulated within closed channels, open-space microfluidics has emerged as a new class of techniques that are well suited for ver-satile interaction with biological substrates. In part ...

EPFL2019

Performance improvement of chip-level CMOS-integrated ReRAM cells through material optimization

Yusuf Leblebici, Thomas La Grange, Tugba Demirci, Elmira Shahrabi

The integration of the resistive random access memory (ReRAM) with CMOS logic circuitry provides a solution to scaling limitations, and offers promising candidates for use in next generation computing applications. It is challenging to realize a reliable, ...

ELSEVIER SCIENCE BV2019

Effect of O2 migration in Pt/HfO2/Ti/Pt structure

Giovanni De Micheli, Pierre-Emmanuel Julien Marc Gaillardon, Maxime Victor Thammasack

In this paper, we study the post-fabrication phenomenon of natural oxidation of the Ti layer observed in a Pt/HfO2/Ti/Pt Resistive Random Access Memory (OxRRAM) stack with no external influence. We identify that the resistance ratio decreases by ...

Springer Verlag2017

Critical heat flux: Performance of R1234yf, R1234ze and R134a in an aluminum multi-minichannel heat sink at high saturation temperatures

John Richard Thome

In this paper, new saturated critical heat flux (CHF) values at medium-to-high saturation temperatures are presented for an aluminum multi-minichannel test section. Among the possible working fluids, R134a and the low GWP refrigerants R1234yf and R1234ze h ...

Elsevier France-Editions Scientifiques Medicales Elsevier2016

Electrochemistry in Supercritical Fluids: A Mini Review

Manuel Alejandro Méndez Agudelo, Patrick Voyame, Kathryn Ellen Toghill

A brief overview of the literature relating to electrochemical studies and processes undertaken in supercritical fluids is presented. This review mostly concerns carbon dioxide and hydrofluorocarbons, given the accessibility of their supercritical states, ...

Elsevier2014

Intermittent dewetting and dryout of annular flows

John Richard Thome, Navid Borhani

Flow visualisation of saturated flow boiling of refrigerant R245fa in a silicon parallel multi-microchannel evaporator, at low mass flux and moderate uniform heat flux, has been carried out with a high-speed digital camera. Using the time-strip technique t ...

Pergamon-Elsevier Science Ltd2014

High aspect ratio etching of nanopores in PECVD SiC through AAO mask

Jürgen Brugger, Songmei Wu, Vaida Auzelyte, Wei Tang

We present in this work the fabrication of high aspect ratio nanopores in 500 nm PECVD SiC films through AAO (anodic aluminum oxide) mask. The initial AAO thin film is 180 nm thick and the diameter of nanopores is 33 ± 7 nm. We have used three plasma chemi ...

IEEE2013

Transfer and State Changes of Fluorine at Polytetrafluoroethylene/Titania Boundaries by Mechanical Stressing and Thermal Annealing

Vincent Laporte

Fluorine in polytetrafluoroethylene (PTFE) changes its states and transfers to titania by comilling and annealing of a titania-PTFE mixture. XPS, F-19 MAS NMR, FT-IR. Raman spectra, TEM and EDX analyses consistently indicated the oxidative decomposition of ...

Amer Chemical Soc2013

Reactivity of BrCl, Br2, BrOCl, Br2O and HOBr toward dimethenamid in solutions of bromide + aqueous free chlorine

Jeremy Samuel Arey, Peter Rudolf Tentscher

HOBr, formed via oxidation of bromide by free available chlorine (FAC), is frequently assumed to be the sole species responsible for generating brominated disinfection byproducts (DBPs). Our studies reveal that BrCl, Br-2, BrOCl, and Br2O can also serve as ...

Amer Chemical Soc2013

CO2 and R410A: Two-phase flow visualizations and flow boiling measurements at medium (0.50) reduced pressure

John Richard Thome

The conversion to more environmentally friendly refrigerants is of prime importance for refrigeration and air-conditioning industries. A first option for the substitution of the fluids which use was banned could be natural refrigerants, such as CO2, or HFC ...

Pergamon-Elsevier Science Ltd2012

Two-phase frictional pressure drops in U-bends and contiguous straight tubes for different refrigerants, orientations, tube, and bend diameters: Part 1. Experimental results (RP-1444)

John Richard Thome, Ricardo Lima

Over the years, much research has been conducted on two-phase flows in straight tubes because these tend, in length, to be predominant in two-phase systems. However, two-phase heat exchangers can also have singularity elements, where the most common type i ...

Taylor & Francis Inc2012

Estimation of road traffic emission factors from a long term tracer study

Alain Clappier, Erika Maria Zarate Torres

Road traffic emissions, one of the largest source categories in megacity inventories, are highly uncertain. It is essential to develop methodologies to reduce these uncertainties to manage air quality more effectively. In this paper, we propose a methodolo ...

Elsevier2009