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Stronger 3D prints

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3D printing is a manufacturing process used for both consumer and industrial applications in the aeronautics, automotive, rail and medical industries. The Shoryuken project being developed at IMT Nord Europe aims to improve the mechanical performance of the objects printed using plastic and composite materials. To accomplish this, it combines 3D printing with laser welding technology.

In the industrial world, certain parts of cars, trains, airplanes, prostheses and orthoses are now manufactured using 3D printing. This manufacturing method enables the small-scale production of customized, geometrically complex parts using 3D digital models, without requiring expensive, specifically designed molds. This procedure saves time and materials when producing prototypes and products to be marketed. However, 3D printing has its limits, especially in relation to structural composite materials, which are plastic materials reinforced with fibers with a high level of resistance and rigidity.

3D printing processes that use composites with yarn containing cut reinforcing fibers generally produce materials with relatively weak mechanical properties. In order to improve the mechanical performance of the printed parts, manufacturing processes using yarns reinforced with continuous fibers are now in high demand in the industry. These yarns are made of thermoplastics, heat-sensitive materials, and continuous carbon or glass yarns. During the printing process, the yarns are melted in order to add the materials they contain layer by layer. The carbon fibers contained in the thermoplastic yarns do not melt and provide the object with solidity and resistance.  

However, the required level of resistance and rigidity can only be obtained in the direction of the fibers, since they are all positioned on a single printing plane. “The current composite 3D printing technology does not allow for the production of parts containing continuous fibrous reinforcements oriented in all the directions desired in space. This is a disadvantage when there are mechanical constraints in three dimensions,” says André Chateau Akue Asseko, researcher in Materials Science at IMT Nord Europe and winner of the Young Researchers call for projects by the French National Research Agency (ANR).

Hybridization of innovative technologies

This is precisely the technological barrier that the new Shoryuken* project seeks to overcome. To accomplish this, the initiative is studying the pairing of 3D printing with laser welding. This combination makes it possible to print two or more components for the same composite part in different printing directions and then use laser welding to assemble them.

“The difficulty stems from the presence of fibers or porosity, which disrupt the laser beam path due to the heterogeneity, which introduces thermal and optical diffusion phenomena,” the scientist explains. This assembly process therefore requires that the small areas filled with thermoplastics be treated differently during 3D printing. The laser radiation melts the thermoplastic polymer in a targeted manner with the composite material surrounding it. Once they are welded together, the two components become inseparable. This makes it possible to produce objects containing reinforcing fibers positioned in ways that allow them to resist mechanical loads in different directions.

Virtual engineering to optimize production

Modeling and simulation tools integrating multiphysics coupling are being developed to optimize these innovative design and production processes. These tools therefore contain information on the interaction between the laser and materials and their thermal and mechanical behavior. “Virtual engineering makes it possible to define the optimal assembly conditions that will ensure the quality of the welding interface,” says André Chateau Akue Asseko. The software, populated with information on the materials of interest, such as melting points, is used to simulate the behavior of two materials that are welded together in order to prevent spending too much time and materials on 3D printing tests.

The user can therefore adjust the laser parameters in order to conduct an optimal weld right away. “These simulations allows us to identify the optimal temperature and speed ranges for welding,” the researcher explains. The development of this type of tool would allow companies to reduce their development and industrialization costs before production by avoiding potential assembly problems. This would ensure the mechanical performance of the manufactured goods.

Read more on I’MTech: 3D printing, a revolution for the construction industry?

Multisectoral applications

 “For this project, we chose to focus on the health sector by producing a prosthetic arm as a demonstrator,” says the scientist, who is currently in contact with companies specialized in prosthesis design. André Chateau Akue Asseko explains that he initially chose to prioritize this sector for pragmatic reasons. “There is strong demand in this field for customized items, adapted to the users’ morphology. The parts are reasonably sized and compatible with the capabilities of our experimental equipment,” the researcher says.

The Shoryuken project will end in 2026. By that time, the future process and digital tool could convince other industries, such as the rail and automotive sectors, of the benefits of customizing parts and tailoring their functionalization for small and medium-scale production runs. For transportation companies, the significantly lighter weights of the parts designed and produced help to cut down on fuel consumption and thereby reduce carbon emissions, which are a key concern in the current global environmental context.

Rémy Fauvel

* The ANR JCJC SHORYUKEN project on the “Assembly of Hybrid Thermoplastic and Thermosetting Carbon Composite: Customization of Complex Structures” is funded by the French National Research Agency (ANR) as part of the 2021 Generic Call for Proposals (AAPG 2021 – CE10) on “Industry and Factories of the Future: People, Organization, Technology.”

IN-TRACKS: tracking energy consumption

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Nowadays, companies are encouraged to track their energy consumption, specifically to limit their greenhouse gas emissions. IN-TRACKS, a start-up created last November, has developed a smart dashboard to visualize energy usage.

“With rising energy costs, these days it is useful for companies and individuals to identify their excessive uses of energy,” says Léo-Paul Keyser, co-founder of In-Tracks.  In November 2021, the IMT Nord Europe graduate created the start-up with Stéphane Flandre, former Enedis executive. The young company, incubated at IMT Nord Europe, provides monitoring solutions to companies to track their energy consumption via a digital dashboard. The software, which can be accessed via computer, smartphone or tablet, displays a range of information pertaining to energy usage.

Typically, graphics show consumption according to peak and off-peak times, depending on the surface area of a room, house or building. “A company may have several premises for which it wishes to track energy consumption,” says Keyser. “The dashboard provides maps and filters that make it possible to select regions, sites, or kinds of equipment for which the customer wishes to compare energy performance,” he adds.

For advice and clarification, “clients can request a videocall so we can help them interpret and understand their data, with our engineers’ expertise,” continues the start-up’s co-founder. The young company also wishes to develop a system of recommendations based on artificial intelligence, analyzing consumption data and sending advice on the dashboard.

The load curve: a tool for analysis

The specificities of clients’ energy use are defined based on load curves: graphics generated by smart electricity and gas meters, which show evolutions in energy consumption over a set period. To obtain access to these curves, In-Tracks has created an agreement with EDF and Enedis. “With the data from the meters received every hour or five minutes, we can try to track the client’s consumption in real-time,” explains the young entrepreneur.

The shorter the intervals at which data is received from the meter, typically every few seconds rather than every few minutes, the more detailed the load curve will be and the more relevant the analysis in diagnosing energy use. By comparing a place’s load curve values to its expected energy consumption threshold, excessive uses can be identified.

Thanks to the dashboard, clients can identify sub-optimal zones and equipment. They can therefore not only reduce their energy bills but also their carbon footprint, i.e. their greenhouse gas emissions, which are also evaluated by the start-up. To do so, the company bases itself on the quantity of fossil energies used, for instance, with natural gas or biodiesel. “We plan to use programs that make it possible to track variations in the energy mix in real-time, in order to get our results as close as possible to reality,” Keyser remarks.

An application accessible to individuals

The young company plans to make an application available to individuals, allowing them to visualize consumption data from smart meters. The software will display the same data as for companies, specifically, energy consumption over time, according to the surface area. In-Tracks also wishes to add a fun side to its application.

“For example, we would like to set up challenges between friends and family members, for everyone to reduce their energy consumption,” explains Keyser. “The aim is to make the subject of energy consumption something that’s fun rather than a source of restrictions,” he adds. To develop this aspect, the start-up is working with students from IMT Nord Europe. The young company is also undertaking research into the Internet of Things, in order to create data analysis methods that make it possible to identify energy issues even more specifically.

Rémy Fauvel

interference

Interference: a source of telecommunications problems

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The growing number of connected objects is set to cause a concurrent increase in interference, a phenomenon which has remained an issue since the birth of telecommunications. In the past decade, more and more research has been undertaken in this area, leading us to revisit the way in which devices handle interference.

“Throughout the history of telecommunications, we have observed an increase in the quantities of information being exchanged,” states Laurent Clavier, telecommunications researcher at IMT Nord Europe. “This phenomenon can be explained by network densification in particular,” adds the researcher. The increase in the amount of data circulating is paired with a rise in interference, which represents a problem for network operations.

To understand what interference is, first, we need to understand what a receiver is. In the field of telecommunications, a receiver is a device that converts a signal into usable information — like an electromagnetic wave into a voice. Sometimes, undesired signals disrupt the functioning of a receiver and damage the communication between several devices. This phenomenon is known as interference and the undesired signal, noise. It can cause voice distortion during a telephone call, for example.

Interference occurs when multiple machines use the same frequency band at the same time. To avoid interference, receivers choose which signals they pick up and which they drop. While telephone networks are organized to avoid two smartphones interfering with each other, this is not the case for the Internet of Things, where interference is becoming critical.

Read on I’MTech: Better network-sharing with NOMA

Different kinds of noise causing interference

With the boom in the number of connected devices, the amount of interference will increase and cause the network to deteriorate. By improving machine receivers, it appears possible to mitigate this damage. Most connected devices are equipped with receivers adapted for Gaussian noise. These receivers make the best decisions possible as long as the signal received is powerful enough.

By studying how interference occurs, scientists have understood that it does not follow a Gaussian model, but rather an impulsive one. “Generally, there are very few objects that function together at the same time as ours and near our receiver,” explains Clavier. “Distant devices generate weak interference, whereas closer devices generate strong interference: this is the phenomenon that characterizes impulsive interference,” he specifies.

Reception strategies implemented for Gaussian noise do not account for the presence of these strong noise values. They are therefore easily misled by impulsive noise, with receivers no longer able to recover the useful information. “By designing receivers capable of processing the different kinds of interference that occur in real life, the network will be more robust and able to host more devices,” adds the researcher.

Adaptable receivers

For a receiver to be able to understand Gaussian and non-Gaussian noise, it needs to be able to identify its environment. If a device receives a signal that it wishes to decode while the signal of another nearby device is generating interference, it will use an impulsive model to deal with the interference and decode the useful signal properly. If it is in an environment in which the devices are all relatively far away, it will analyze the interference with a Gaussian model.

To correctly decode a message, the receiver must adapt its decision-making rule to the context. To do so, Clavier indicates that a “receiver may be equipped with mechanisms that allow it to calculate the level of trust in the data it receives in a way that is adapted to the properties of the noise. It will therefore be capable of adapting to both Gaussian and impulsive noise.” This method, used by the researcher to design receivers, means that the machine does not have to automatically know its environment.

Currently, industrial actors are not particularly concerned with the nature of interference. However, they are interested in the means available to avoid it. In other words, they do not see the usefulness of questioning the Gaussian model and undertaking research into the way in which interference is produced. For Clavier, this lack of interest will be temporary, and “in time, we will realize that we will need to use this kind of receiver in devices,” he notes. “From then on, engineers will probably start to include these devices more and more in the tools they develop,” the researcher hopes.

Rémy Fauvel

France’s elderly care system on the brink of crisis

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In his book Les Fossoyeurs (The Gravediggers), independent journalist Victor Castanet challenges the management of the private elderly care facilities of world leader Orpea, reopening the debate around the economic model – whether for-profit or not – of these structures. Ilona Delouette and Laura Nirello, Health Economics researchers at IMT Nord Europe, have investigated the consequences of public (de)regulation in the elderly care sector. Here, we decode a system that is currently on the brink of crisis.

The Orpea scandal has been at the center of public debate for several weeks. Rationing medications and food, a system of kickback bribes, cutting corners on tasks and detrimental working conditions are all practices that Orpea group is accused of by Victor Castenet in his book,”Les Fossoyeurs”. Through this abuse in private facilities is currently casting aspersions on the entire sector, professionals, families, NGOs, journalists and researchers have been denouncing such dysfunction for several years.

Ilona Delouette and Laura Nirello, Health Economics researchers at IMT Nord Europe, have been studying public regulation in the elderly care sector since 2015. During their inquiries, the two researchers have met policy makers, directors and employees of these structures. They came to the same conclusion for all the various kinds of establishments: “in this sector, the challenging burden of funding is now omnipresent, and working conditions and services provided have been continuously deteriorating,” emphasizes Laura Nirello. For the researchers, these new revelations about the Orpea group reveal a basic trend more than anything else: the progressive competition between these establishments and cost-cutting imperatives has put more and more distance between them and their original missions.

From providing care for dependents…

In 1997, to deal with the growth in the number of dependent elderly, the category of nursing homes known as ‘Ehpad’ was created. “Since the 1960s, there has been debate around providing care for the elderly with decreasing autonomy from the public budget. In 1997, the decision was made to remove loss of autonomy from the social security system; it became the responsibility of the departments,” explained Delouette. From then on, public organizations, such as those in the social and solidarity-based economy (SSE), entered into competition with private, for-profit establishments.  25 years later, out of the 7,400 nursing homes in France that house a little less than 600,000 residents, nearly 50% of them are public, around 30% are private, not-for-profit (SSE) and around 25% are private and for-profit.

The (complex) funding of these structures, regulated by regional health agencies (ARS) and departmental councils, is organized into three sections: the ‘care’ section (nursing personnel, medical material, etc.) handled by the French public health insurance body Assurance Maladie; the ‘dependence’ section (daily life assistance, carers, etc.) managed by the departments via the personal autonomy benefit (APA); and the final section, accommodation fees, which covers lodgings, activities and catering, at the charge of residents and their family.

“Public funding is identical for all structures, whether private — for-profit or not-for-profit — or public. It’s often the cost of accommodation, which is less regulated, that receives media coverage, as it can run to several thousand euros,” emphasizes Nirello. “And it is mainly on this point that we see major disparities, justified by the private for-profit sector by higher real estate costs in urban areas. But it’s mainly because half of these places are owned by companies listed on the stock market, with the profitability demands that this involves,” she continues. And while companies are facing a rise in dependence and need for care from their residents, funding is frozen.

…to the financialization of the elderly

A structure’s resources are determined by its residents’ average level of dependency, transposed to working time. This is evaluated according to the AGGIR table (“Autonomie Gérontologie Groupes Iso-Ressources” or Autonomy Gerontology Iso-Resource Groups): GIR 1 and 2 correspond to a state of total or severe dependence, GIR 6 to people who are completely independent. Nearly half of nursing home residents belong to GIR 1 and 2, and more than a third to GIR 3 and 4. “While for-profit homes are positioned for very high dependence, public and SSE establishments seek to have a more balanced mix. They are often older and have difficulties investing in new, adapted facilities to handle highly dependent residents,” indicates Nirello. Paradoxically, the rate of assistants to residents is very different according to a nursing home’s status: 67% for public homes, 53% for private not-for-profit and 49% for private for-profit.

In the context of tightening public purse strings, this goes alongside a phenomenon of extreme corner-cutting for treatment, with each operation charged for. “Elderly care nurses need time to take care of residents: autonomy is fundamentally connected to social interaction,” insists Delouette. The Hospital, Patients, Health, Territories law strengthened competition between the various structures: from 2009, new authorizations for nursing home creation and extension were established based on calls for project issued by ARSs. For the researcher, “this system once again places groups of establishments in competition for new locations, as funding is awarded to the best option in terms of price and service quality, no matter its status. We know who wins: 20% public, and 40-40 for private for-profit/not-for-profit. What we don’t know is who responds to these calls for project. With tightened budgets, is the public sector no longer responding or is this a choice by regulators in the field?”

What is the future for nursing homes?

“Funding, cutting corners, a managerial view of caring for dependents: the entire system needs to be redesigned. We don’t have solutions, we are making observations,” emphasizes Nirello.But despite promises, reform has been delayed too long.The Elderly and Autonomy law, the most recent effort in this area, was announced by the current government and buried in late 2019, despite two parliamentary reports highlighting the serious aged care crisis (the mission for nursing homes in March 2018 and the Libault report in March 2019).

In 2030, Insee estimates that there will be 108,000 more dependent elderly people; 4 million in total in 2050. How can we prepare for this demographic evolution, currently underway? Just to cover the increased costs of caring for the elderly with loss of autonomy, it would take €9 billion every year until 2030. “We can always increase funding; the question is how we fund establishments. If we continue to try to cut corners on care and tasks, this goes against the social mission of these structures. Should vulnerable people be sources of profit? Is society prepared to invest more in taking care of dependent people?” asks Delouette. “This is society’s choice.” The two researchers are currently working on the management of the pandemic in nursing homes. For them, there is still a positive side to all this: the state of elderly care has never been such a hot topic.

Anne-Sophie Boutaud

Also read on I’MTech:

In French nursing homes, the Covid-19 crisis has revealed the detrimental effects of austerity policies
RI-URBANS

Improving air quality with decision-making tools

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Launched in October for a four-year period, the RI-URBANS project aims to strengthen synergies between European air quality monitoring networks and research infrastructures in the field of atmospheric sciences. IMT Nord Europe is a partner for this project, which received up to €8 million of funding from the European Union. Interview with  Stéphane Sauvage, professor, and Thérèse Salameh, R&D engineer.

European project RI-URBANS[1] was submitted in response to a call for tender dedicated to research infrastructures (RI) capable of tackling the challenges set by the European Green Deal. What is it all about?

Stéphane Sauvage The EU aims to play a leading role in fighting climate change at a global level. In a communication dated 14 July 2021, the 27 member states committed to turning the EU into the first climate neutral continent by 2050. To achieve this, they committed to reduce their greenhouse gas emissions by at least 55% by 2030, compared to levels in 1990, and to implement a series of initiatives related to the climate, energy, agriculture, industry, environment, oceans, etc.. Specifically, the Green Deal aims to protect our biodiversity and ecosystems, transition to a circular economy and reduce air, water and soil pollution. RI-URBANS falls under this initiative to reduce air pollution.

What is the goal of RI-URBANS?

S.S. Within this project, the objective is to connect the Aerosol, Clouds, and Trace gases Research InfraStructure (ACTRIS), Integrated Carbon Observation System (ICOS) and In-service Aircraft for a Global Observing System (IAGOS) – combining stationary and mobile observation and exploration platforms, calibration centers and data centers – with local stakeholders, such as air quality monitoring agencies, political decision-makers or regional stakeholders. The main objective is to provide them with high quality data and develop innovative service tools allowing them to better evaluate the health impact, identify sources of pollution in real time and forecast atmospheric pollution, in order to help decision-makers in improving air quality.

How will these tools be developed?

S.S. RI-URBANS will focus on ambient nanoparticles and atmospheric particulate matter, their sizes, constituents, source contributions, and gaseous precursors, evaluating novel air quality parameters, source contributions, and their associated health effects to demonstrate the European added value of implementing such service tools. To determine which areas are of interest, we have first to collect the available data on these variables and make it findable, accessible, interoperable and reusable, while offering decision-makers services and tools.

In order to test these services, a pilot phase will be deployed in nine European cities (Athens, Barcelona, Birmingham, Bucharest, Helsinki, Milan, Paris, Rotterdam-Amsterdam and Zurich). These cities have been identified as industrial, port, airport and road hotspots, with significant levels of pollution and have established air quality monitoring networks and research infrastructure units. In Paris, for example, the atmospheric research observatory SIRTA is a unit of ACTRIS and one of the most prominent sites in Europe offering the instrumentation, equipment and hosting capacities needed to study atmospheric physico-chemical processes.

What expertise do the IMT Nord Europe researchers bring?

Thérèse Salameh IMT Nord Europe research teams have internationally recognized expertise in the field of reactive trace gases, which can lead to the formation of secondary compounds, such as ozone or secondary organic aerosols. IMT Nord Europe’s participation in this project is connected to its significant involvement in the ACTRIS (Aerosol, Clouds, and Trace Gases Research InfraStructure) RI as a unit of the European Topical Center for reactive trace gases in situ measurements (CiGas). ACTRIS is a distributed RI bringing together laboratories of excellence and observation and exploration platforms, to support research on climate and air quality. It helps improve understanding of past, present and future changes in atmospheric composition and the physico-chemical processes that contribute to regional climate.

Who are the partners of RI-URBANS?

T.S. The project brings together 28 institutions (universities and research institutes) from 14 different countries. The three partners in France are the National Centre for Scientific Research (CNRS), National Institute for Industrial Environment and Risks (INERIS) and Institut Mines-Télécom (IMT). For this project, IMT Nord Europe researchers are collaborating in particular with Swiss federal laboratories for materials science and technology Empa, Paul Scherrer Institute (PSI), Spanish National Research Council (CSIC) and INERIS.

The project has just been launched. What is the next step for IMT Nord Europe?

T.S. In the coming months, we will conduct an assessment collecting observation data for reactive trace gases potentially available in main European cities. We will then need to evaluate the quality and relevance of the collected information, before applying source apportionment models to identify the main sources of pollution in these European cities.

[1] This project is funded by Horizon 2020, the European Union framework program for research and innovation (H2020), with grant agreement ID 101036245. It is conjointly coordinated by CSIC (Spain) and University of Helsinki (Finland). Find out more.

Read on I’MTech

Easier access to research infrastructure for the European atmospheric science community
Atmospheric reactive trace gases: low concentrations, major consequences