Tag Archives: [France] Commissariat a l’Energie Atomique (CEA)

Testing ‘smart’ antibacterial surfaces and eating haute cuisine in space

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Housekeeping in space, eh? This seems to be a French initiative. From a Nov. 15, 2016 news item on Nanowerk,

Leti [Laboratoire d’électronique des technologies de l’information (LETI)], an institute of CEA [French Alternative Energies and Atomic Energy Commission or Commissariat a l’Energie Atomique (CEA)] Tech, and three French partners are collaborating in a “house-cleaning” project aboard the International Space Station that will investigate antibacterial properties of new materials in a zero-gravity environment to see if they can improve and simplify cleaning inside spacecraft.

The Matiss experiment, as part of the Proxima Mission sponsored by France’s CNES space agency [Centre national d’études spatiales (CNES); National Centre for Space Studies (CNES)], is based on four identical plaques that European Space Agency (ESA) astronaut Thomas Pesquet, the 10th French citizen to go into space, will take with him and install when he joins the space station in November for a six-month mission. The plaques will be in the European Columbus laboratory in the space station for at least three months, and Pesquet will bring them back to earth for analysis at the conclusion of his mission.

A November 15, 2016 CEA-LETI press release on Business Wire (you may also download it from here), which originated the news item, describes the proposed experiments in more detail,

Leti, in collaboration with the ENS de Lyon, CNRS, the French company Saint Gobain and CNES, selected five advanced materials that could stop bacteria from settling and growing on “smart” surfaces. A sixth material, made of glass, will be used as control material.

The experiment will test the new smart surfaces in a gravity-free, enclosed environment. These surfaces are called “smart” because of their ability to provide an appropriate response to a given stimulus. For example, they may repel bacteria, prevent them from growing on the surface, or create their own biofilms that protect them from the bacteria.

The materials are a mix of advanced technology – from self-assembly monolayers and green polymers to ceramic polymers and water-repellent hybrid silica. By responding protectively to air-borne bacteria they become easier to clean and more hygienic. The experiment will determine which one is most effective and could lead to antibacterial surfaces on elevator buttons and bars in mass-transit cars, for example.

“Leveraging its unique chemistry platform, Leti has been developing gas, liquid and supercritical-phase-collective processes of surface functionalization for more than 10 years,” said Guillaume Nonglaton, Leti’s project manager for surface chemistry for biology and health-care applications. “Three Leti-developed surfaces will be part of the space-station experiment: a fluorinated thin layer, an organic silica and a biocompatible polymer. They were chosen for their hydrophobicity, or lack of attraction properties, their level of reproducibility and their rapid integration within Pesquet’s six-month mission.”

Now, for Haute Cusine

Pesquet is bringing meals from top French chefs Alain Ducasse and Thierry Marx for delectation. The menu includes beef tongue with truffled foie gras and duck breast confit. Here’s more from a Nov. 17, 2016 article by Thibault Marchand (Agence France Presse) ong phys.org,

“We will have food prepared by a Michelin-starred chef at the station. We have food for the big feasts: for Christmas, New Year’s and birthdays. We’ll have two birthdays, mine and Peggy’s,” said the Frenchman, who is also taking a saxophone up with him.

…

French space rookie Thomas Pesquet, 38, will lift off from the Baikonur cosmodrome in Kazakhstan with veteran US and Russian colleagues Peggy Whitson and Oleg Novitsky, for a six-month mission to the ISS.

Bon appétit! By the way, this is not the first time astronauts have been treated to haute cuisine (see a Dec. 2, 2006 article on the BBC [British Broadcasting Corporation] website.)

The launch

Mark Garcia’s Nov. 17, 2016 posting on one of the NASA (US National Aeronautics and Space Administration) blogs describes this latest launch into space,

The Soyuz MS-03 launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 3:20 p.m. EST Thursday, Nov. 17 (2:20 a.m. Baikonur time, Nov. 18). At the time of launch, the space station was flying about 250 miles over the south Atlantic east of Argentina. NASA astronaut Peggy Whitson, Oleg Novitskiy of Roscosmos and Thomas Pesquet of ESA (European Space Agency) are now safely in orbit.

Over the next two days, the trio will orbit the Earth for approximately two days before docking to the space station’s Rassvet module, at 5:01 p.m. on Saturday, Nov. 19. NASA TV coverage of the docking will begin at 4:15 p.m. Saturday.

Garcia’s post gives you details about how to access more information about the mission. The European Space Agency also offers more information as does Thomas Pesquet on his website.

Identifying performance problems in nanoresonators

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Use of nanoelectromechanical systems (NEMS) can now be maximised due to a technique developed by researchers at the Commissariat a l’Energie Atomique (CEA) and the University of Grenoble-Alpes (France). From a March 7, 2016 news item on ScienceDaily,

A joint CEA / University of Grenoble-Alpes research team, together with their international partners, have developed a diagnostic technique capable of identifying performance problems in nanoresonators, a type of nanodetector used in research and industry. These nanoelectromechanical systems, or NEMS, have never been used to their maximum capabilities. The detection limits observed in practice have always been well below the theoretical limit and, until now, this difference has remained unexplained. Using a totally new approach, the researchers have now succeeded in evaluating and explaining this phenomenon. Their results, described in the February 29 [2016] issue of Nature Nanotechnology, should now make it possible to find ways of overcoming this performance shortfall.

A Feb. 29, 2016 CEA press release, which originated the news item, provides more detail about NEMS and about the new technique,

NEMS have many applications, including the measurement of mass or force. Like a tiny violin string, a nanoresonator vibrates at a precise resonant frequency. This frequency changes if gas molecules or biological particles settle on the nanoresonator surface. This change in frequency can then be used to detect or identify the substance, enabling a medical diagnosis, for example. The extremely small dimensions of these devices (less than one millionth of a meter) make the detectors highly sensitive.

However, this resolution is constrained by a detection limit. Background noise is present in addition to the wanted measurement signal. Researchers have always considered this background noise to be an intrinsic characteristic of these systems (see Figure 2 [not reproduced here]). Despite the noise levels being significantly greater than predicted by theory, the impossibility of understanding the underlying phenomena has, until now, led the research community to ignore them.

The CEA-Leti research team and their partners reviewed all the frequency stability measurements in the literature, and identified a difference of several orders of magnitude between the accepted theoretical limits and experimental measurements.

In addition to evaluating this shortfall, the researchers also developed a diagnostic technique that could be applied to each individual nanoresonator, using their own high-purity monocrystalline silicon resonators to investigate the problem.

The resonant frequency of a nanoresonator is determined by the geometry of the resonator and the type of material used in its manufacture. It is therefore theoretically fixed. By forcing the resonator to vibrate at defined frequencies close to the resonant frequency, the CEA-Leti researchers have been able to demonstrate a secondary effect that interferes with the resolution of the system and its detection limit in addition to the background noise. This effect causes slight variations in the resonant frequency. These fluctuations in the resonant frequency result from the extreme sensitivity of these systems. While capable of detecting tiny changes in mass and force, they are also very sensitive to minute variations in temperature and the movements of molecules on their surface. At the nano scale, these parameters cannot be ignored as they impose a significant limit on the performance of nanoresonators. For example, a tiny change in temperature can change the parameters of the device material, and hence its frequency. These variations can be rapid and random.

The experimental technique developed by the team makes it possible to evaluate the loss of resolution and to determine whether it is caused by the intrinsic limits of the system or by a secondary fluctuation that can therefore by corrected. A patent has been applied for covering this technique. The research team has also shown that none of the theoretical hypotheses so far advanced to explain these fluctuations in the resonant frequency can currently explain the observed level of variation.

The research team will therefore continue experimental work to explore the physical origin of these fluctuations, with the aim of achieving a significant improvement in the performance of nanoresonators.

The Swiss Federal Institute of Technology in Lausanne, the Indian Institute of Science in Bangalore, and the California Institute of Technology (USA) have also participated in this study. The authors have received funding from the Leti Carnot Institute (NEMS-MS project) and the European Union (ERC Consolidator Grant – Enlightened project).

Here’s a link to and a citation for the paper,

Frequency fluctuations in silicon nanoresonators by Marc Sansa, Eric Sage, Elizabeth C. Bullard, Marc Gély, Thomas Alava, Eric Colinet, Akshay K. Naik, Luis Guillermo Villanueva, Laurent Duraffourg, Michael L. Roukes, Guillaume Jourdan & Sébastien Hentz. Nature Nanotechnology (2016) doi:10.1038/nnano.2016.19 Published online 29 February 2016

This paper is behind a paywall.