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EURAXESS

MSCA-COFUND-CLEAR-Doc - PhD Position #CD22-16: Innovative bio-based construction materials with improved moisture buffering and heat transfer properties

14/10/2022

Job Information

Organisation/Company
Université Gustave Eiffel
Department
NAVIER
Research Field
Engineering
Engineering » Civil engineering
Physics
Physics » Applied physics
Researcher Profile
First Stage Researcher (R1)
Country
France
Application Deadline
Type of Contract
Temporary
Job Status
Full-time
Hours Per Week
35
Is the job funded through the EU Research Framework Programme?
H2020 / Marie Skłodowska-Curie Actions COFUND
Marie Curie Grant Agreement Number
101034248
Is the Job related to staff position within a Research Infrastructure?
No

Offer Description

"Housing and buildings in general are the EU’s most important energy consumers and polluters. Improvements in this field are expected to contribute to meeting the EU climate-neutral objective of net-zero greenhouse gas emissions by 2050. In this regard, the use of bio-based construction materials for construction or renovation is currently growing as these materials are recognized as a means to reduce carbon dioxide emissions from construction through: (i) their sustainable production as crops grown annually or as longer harvest-cycle foresting, including secondary products from food growth, (ii) their contribution to air quality, (iii) the reduction of energy consumption for heating or cooling which they induce, (iv) their partial or full recyclability, and (v) their long term use in construction acting as a carbon sink. Such materials include pilings of natural fibers (or bio-elements) derived from wood, wheat, jute, flax, bamboo, straw, coir, cotton, pulp, etc., mainly used for insulation, or dispersions of plant materials (wood, hemp, cellulose wadding, straw, etc.), coated by a mineral matrix (lime, cement, earth, plaster, clay, etc.) generally used as filling for walls or for insulation: hemp concrete, wood concrete, flax concrete, adobe, cob, etc.

One important characteristic of bio-based construction materials is that they are hygroscopic, i.e., they can absorb (resp. release) a significant fraction of vapor as (resp. from) “bound water” inside the solid bio-components of the structure thanks to the presence of hydroxyl groups associated with the cell-wall macromolecules. This bound water plays several important roles. It favors the comfort of building occupants by ensuring a “moisture buffering” effect, in the sense that it reduces the daily variations of moisture, or more precisely the relative humidity (RH) in the air; in particular, this reduces ventilation requirements and thus curbs energy consumption. Also, due to the large latent heat (close to that associated with the liquid-vapor transition) associated with sorption or desorption processes, bio-based elements behave as phase-change materials, releasing heat as a result of sorption when the ambient temperature decreases. These coupled heat and moisture transfers in building envelopes have a significant impact on the annual cooling and heating energy consumption and the indoor thermal and humidity environment, but moisture transfer processes in building envelopes are not generally taken into account in current conventional thermal calculations and energy consumption analyses. This in particular precludes a correct estimation of a building’s performance with respect to thermal regulations. In order to develop and optimize the use of such materials it is crucial to be able: (i) to quantify and predict their physical properties, (ii) to properly predict and thus control the hygrothermal behavior of buildings in use, and (iii) to develop innovative products with higher efficiency. This requires an in-depth understanding of the processes.

The major problem hindering progress is the lack of information and proper description of water transport and phase changes inside the porous structure. Measurements remain challenging, in particular considering that the materials are non-transparent and different states of water (free liquid water, bound water, vapor) can coexist.

The Navier Laboratory has a Magnetic Resonance Imager (MRI) and several NMR Spectrometers dedicated to applications in civil engineering. We recently achieved a world first by demonstrating the possibility to measure the evolution of the distribution of free and bound water in wood, with the help of appropriate NMR and MRI sequences (T2 distribution in time, multi-echo alternating with Single-Point-Imaging) [1-2]. We were also able to measure the spatial distribution over time in cellulose fiber pilings, and fully model the vapor-bound water exchanges and transport through this structure [3].

The present thesis project will focus on typical bio-based insulation materials made by aggregation of of wood, flax, or wheat fibers. The aim will be to fully characterize moisture transport and exchanges in such materials types under various conditions of external air flux, through experimental and modelling approaches. The fiber size, the particle orientations, and the porosity of the materials will be varied. Depending on time heat transfers will also be studied, with the help of home-made systems under development.

Moreover, complementary in-situ X-ray imaging and X-ray wide- and small-angle X-ray scattering (SAXS/WAXS) are planned in a collaboration with P. Huber to correlate the NMR data with spatio-temporally resolved water distributions in pore space. These goals shall particularly profit from a 6 months visit in P.Huber’s lab in Hamburg as well as joined experiments at synchrotron-based X-ray beamlines at PETRA III (Hamburg), or at ESRF (Grenoble) and Soleil (Paris).

The different techniques used will allow to get a complete set of data concerning the hygrothermal evolution of these controlled systems under controlled boundary conditions. This will allow us to develop models taking into account the different transport and transfers between phases and fully validate it by comparison with data at a local scale, which is a unique situation in the field of construction materials.

This work should lead to a clarification of the physical processes at work in various insulation and bio-based construction materials, provide some relevant means for their characterization, offer some practical recommendations on the most appropriate characteristics, and open the way to the development of new high performance materials.

This work will be mainly carried out within Laboratoire Navier, Physics and Porous Media Team, with P. Coussot (http://philippecoussot.com) as official supervisor, and in collaboration with R. Sidi-Boulenouar and B. Maillet from the NMR Team, and with Patrick Huber group (https://huberlab.wp.tuhh.de) in Hamburg.

The candidate is expected to have a strong motivation for research and a background in physics, fluid mechanics, or physicochemistry.

References:

[1] Penvern et al, How bound water regulates wood drying, Physical Review Applied, 14, 054051 (2020) - Editor’s suggestion – Featured in Physics: https://physics.aps.org/articles/v13/182 - Paper in CNRS News

[2] Cocusse et al, Two-step diffusion in cellular hygroscopic (vascular plant-like) materials, Science Advances, 8, eabm7830 (2022)

[3] Ma et al, Vapor-sorption coupled diffusion in clothes revealed by MRI, Physical Review Applied, 17, 024048 (2022) Featured in Physics: https://physics.aps.org/articles/v15/s22 - Paper in CNRS News"

Requirements

Research Field
Engineering
Education Level
Bachelor Degree or equivalent
Skills/Qualifications
  • At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree.
  • At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
Specific Requirements
  • The candidate is expected to have a strong motivation for research and a background in physics, fluid mechanics, or physicochemistry.
  • A master or equivalent in chemical, physical or mechanical engineering is required.
Languages
FRENCH
Level
Basic
Languages
ENGLISH
Level
Good

Additional Information

Benefits
  • High-quality doctoral training rewarded by a PhD degree, delivered by Université Gustave Eiffel
  • Access to cutting-edge infrastructures for research & innovation.
  • Appointment for a period of 36 months based on a salary of 2 700 € (gross salary per month).
  • Job contract under the French labour legislation in force, respecting health and safety, and social security: 35 hours per week contract, 25 days of annual leave per year.
  • International mobility will be mandatory
  • An international environment supported by the adherence to the European Charter & Code.
  • Access to dedicated CLEAR-Doc trainings with a strong interdisciplinary focus, together with a Career development Plan.
Eligibility criteria

Applicants must fulfil the following eligibility criteria:

  • At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree.
  • At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
  • At the time of the deadline, applicants must be in the first four years (full-time equivalent research experience) of their research career (career breaks excluded) and not yet been awarded a doctoral degree. Career breaks refer to periods of time where the candidate was not active in research, regardless of his/her employment status (sick leave, maternity leave etc). Short stays such as holidays and/or compulsory national service are not taken into account.
  • At the time of the deadline, applicants must fulfil the transnational mobility rule: incoming applicants must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 previous years.

One application per call per year is allowed.

Applicants must be available full-time to start the programme on schedule (November 1st 2023).

Application rules are enforced by the French doctoral system which specifies a standard duration of 3 years for a full-time PhD together with the MSCA standards and the OTM-R European rules as follows.

Citizens of any nationality may apply to the programme.

There is no age limit.

Selection process

Please refer to the Guide for Applicants available on the CLEAR-Doc website.

Additional comments
  • The First step before applying is contacting the PhD supervisor. You will not be able to apply without an acceptation letter from the PhD supervisor.
  • International Mobility: in-situ X-ray imaging and X-ray wide- and small-angle X-ray scattering (SAXS/WAXS) are planned in a collaboration with P. Huber to correlate the NMR data with spatio-temporally resolved water distributions in pore space. These goals shall particularly profit from a 6 months visit in P.Huber’s lab in Hamburg as well as joined experiments at synchrotron-based X-ray beamlines at PETRA III (Hamburg), or at ESRF (Grenoble) and Soleil (Paris). For more information, please contact the PhD supervisor.
  • Please contact the PhD supervisor for any additional detail on job offer.
  • There are no restrictions concerning the age, gender or nationality of the candidates. Applicants with career breaks or variations in the chronological sequence of their career, with mobility experience or with interdisciplinary background or private sector experience are welcome to apply.
  • Support service is available during every step of the application process by email: clear-doc@univ-eiffel.fr
Website for additional job details

Work Location(s)

Number of offers available
1
Company/Institute
Université Gustave Eiffel
Country
France
State/Province
Île de France
City
Marne-la-Vallée
Postal Code
77454
Street
5 boulevard Descartes
Geofield

Contact

City
Marne-La-Vallée
Website
Street
5, Boulevard Descartes
Postal Code
77454
E-Mail
philippe.coussot@univ-eiffel.fr