1,596 research outputs found
Protocol to perform pressurized blister tests on thin elastic films
This work aims to identify common challenges in the preparation of the
blister test devices designed for measurement of energy release rate for
brittle thin films and to propose easy-to-implement solutions accordingly. To
this end, we provide a step-by-step guide for fabricating a blister test device
comprised of thin polystyrene films adhered to glass substrates. Thin films are
first transferred from donor substrates to an air-water interface, which is
then used as a platform to locate them on a receiver substrate. We embed a
microchannel at the back of the device to evacuate the air trapped in the
opening, through which the pressure is applied. We quantify the height and the
radius of the blister to estimate the adhesion energy using the available
expressions correlating the normal force and the moment with the shape of the
blister. The present blister test provided adhesion energy per unit area of \mbox{mJ}/{\mbox m}^2 for polystyrene on glass, which is in good
agreement with the measurement of \mbox{mJ}/{\mbox m}^2 found
in our independent cleavage test
Rescaling the dynamics of evaporating drops
The dynamics of evaporation of wetting droplets has been investigated
experimentally in an extended range of drop sizes, in order to provide trends
relevant for a theoretical analysis. A model is proposed, which generalises
Tanner's law, allowing us to smooth out the singularities both in dissipation
and in evaporative flux at the moving contact line. A qualitative agreement is
obtained, which represents a first step towards the solution of a very old,
complex problem
Water-based peeling of thin hydrophobic films
Inks of permanent markers and water-proof cosmetics create elastic thin films
upon application on a surface. Such adhesive materials are deliberately
designed to exhibit water-repellent behavior. Therefore, patterns made up of
these inks become resistant to moisture and cannot be cleaned by water after
drying. However, we show that sufficiently slow dipping of such elastic films,
which are adhered to a substrate, into a bath of pure water allows complete
removal of the hydrophobic coatings. Upon dipping, the air-water interface in
the bath forms a contact line on the substrate, which exerts a
capillary-induced peeling force at the edge of the hydrophobic thin film. We
highlight that this capillary peeling process is more effective at lower
velocities of the air-liquid interface and lower viscosities. Capillary peeling
not only removes such thin films from the substrate but also transfers them
flawlessly onto the air-water interface
ATLAS Distributed Data management Operations
ATLAS Distributed Data Management (DDM) service is developed for data transfer between ATLAS sites and for data cataloguing. The Data Management Software (SW) is based on DQ2 and end-users tools (aka dq2_get package). In this paper we address the issue of DDM day-by-day operation, DDM operations team organization, roles and responsibilities of Tier-1s and Tier-2s DDM coordinators
From Research to Operational Biomonitoring of Freshwaters: A Suggested Conceptual Framework and Practical Solutions
International audienceThe contradictory demands of managers (quick relevant operational responses) and ecologists (need time for in-depth research) involved in freshwater biomonitoring are still relevant today. To contribute to solving this dilemma, we are proposing a novel biomonitoring approach, which among many others, could be used in this field and further developed in the future. Biomonitoring actions are integrated in conceptual schemes, in which hydrology, chemistry, hydrogeology and geomorphology bear as much importance as biology. Among biomonitoring tools, a harmonization system allows end-users to use a set of qualitative indicators (various biotic indices) and integrate the information given by individual biotic indices. Functional traits and calculation of an ecological potential in porous aquatic habitats (surficial coarse sediments and the hyporheic system) are regarded as a basis for assessing ecological functioning of streams and rivers. This last methodology takes into account the dynamics of water exchanges between surface water and groundwater. Objectives of ecological quality, ecological potentials and resilience capacity that need to be preserved or rehabilitated in aquatic habitats are established. In lakes, a similar approach was followed and a general typology of lake functioning was proposed, including that for urban lakes. All those biomonitoring tools are transferred to end-users and subject to further research. The final purpose is to promote practical high-tech tools which are continually and interactively connected with ongoing research
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