Erik Franco – Pagina 15 – Progress in Research

Church of The Holy Sepulchre floor restoration

Posted on 15/04/202206/08/2024 by Erik Franco

The Politecnico di Milano takes part in the restoration of the floor of the Church of the Holy Sepulchre in Jerusalem. The Politecnico di Milano has created the guidelines for modelling and sharing data for the conservation and restoration project and has performed a detailed survey to document the state of conservation prior to the intervention.

The researchers created models of the floor and the surrounding architecture, starting from the laser scanner data. The high-resolution photogrammetric survey, carried out on site by researchers from the Politecnico between September and October 2021, acquired over 50,000 high-resolution images, using a system designed ad hoc.

The system we designed, consists of a special trolley on which we engineered an articulated lighting and acquisition system, with controlled intensity and colouring. This was integrated with a topographic survey for processing and verifying the final result, a digital image, an orthophoto, with very high resolution, metrically reliable and precise, of the entire floor of the Church of the Holy Sepulchre.
Prof. Luigi Fregonese from the Department of Architecture, Construction Engineering and Built Environment at the Politecnico di Milano

It was a particularly complex task because of the composite architecture of the building, also made up of rooms and underground stratifications, that also required the continuous coordination with the internal staff at the church, in order to avoid interference with normal liturgical activities and visits by pilgrims and tourists.

The project was carried out by the research group MantovaLAB – HESUTECH from the Mantova Campus of the Politecnico di Milano (ABC Department), which is coordinated by professors Andrea Adami, Luigi Fregonese, Stefano della Torre and the Vice Rector of the Mantova Campus Federico Bucci. The project manager for the conservation and restoration of the floor – the start of which has recently been announced – on behalf of the Custody of the Holy Land, is the Centro di Conservazione e Restauro La Venaria Reale [CCR-VR] in Turin, with the support of a multidisciplinary team, while the direction of the archaeological excavation has been entrusted to La Sapienza University of Rome.

Photons to create an artificial quantum neuron

Posted on 13/04/202206/08/2024 by Erik Franco

A group of researchers of the Department of Physics at the Politecnico di Milano, the National Research Council (CNR) and the University of Vienna, have developed a device, called a quantum memristor, which could combine artificial intelligence and quantum computing.

This is an advance that can open up as yet unseen potential, allowing to employ the very high computational power guaranteed by quantum technologies in the fields of application of artificial intelligence, which already range from automatic speech interpretation to face recognition, from medical diagnostics to autonomous driving.

Artificial intelligence algorithms are based on mathematical models called neural networks, inspired by the biological structure of the human brain, which is made up of interconnected nodes (neurons). One of the fundamental components of neural networks is the memristor (or memory-resistor), a component that changes its electrical resistance based on a memory of the current that passed through it, in a way that is surprisingly similar to that of neural synapses, i.e. the connections between neurons in the brain.

The group of experimental physicists led by Roberto Osellame (CNR) has shown that it is possible to engineer an optical device with the same functional characteristics as the memristor, capable of operating on quantum states of light and thus encoding and transmitting quantum information: a quantum memristor.

We also simulated an entire optical network made up of quantum memristors, showing that it could be used to learn both classical and quantum tasks.
Andrea Crespi, professor of Experimental Physics at the Politecnico di Milano

This result seems to suggest that the quantum memristor may be the missing link between artificial intelligence and quantum computing, unleashing the potential of quantum resources within artificial intelligence applications.

The study received the cover of the April issue of Nature Photonics magazine.

The study on Nature Photonics

© photo: Equinox Graphics

Italian Quantum Weeks – Milano

Posted on 05/04/202206/08/2024 by Erik Franco

On the occasion of the first World Quantum Day, Politecnico di Milano, together with Università degli Studi di Milano and CNR IFN of Milan, will participate to the Italian Quantum Weeks, a national event dedicated to quantum mechanics and quantum technologies that will take place in 17 Italian cities.

In Milan the program includes guided tours to the research laboratories of Politecnico di Milano, Università degli Studi di Milano and CNR IFN, seminars on quantum mechanics and the exhibition “Saying the unspeakable: quantum superposition”.

Full program and registration form

GAP: a step forward in preventing bone fractures

Posted on 31/03/202206/08/2024 by Erik Franco

A group of students devised an innovative device and algorithm for understanding and preventing bone fractures. In the course of their lifetime, approximately 40% of Italians will suffer a broken femur, vertebra or wrist. Fractures caused by osteoporosis have major consequences in terms of mortality and motor disability, with high health and social costs.

The GAP project (image-Guided experimental and computational Analysis of fractured Patients) seeks to go beyond the limits of current bone fracture diagnostics to develop more effective methods of early diagnosis. The idea was conceived within the Alta Scuola Politecnica (ASP), the international programme reserved for the best students from the Politecnico di Milano and Politecnico di Torino.

The working group focused on the study of bone fractures at the microscale, where there are still many doubts as to the origin and propagation of fractures. The role of small cavities in the bone architecture, known as lacunae, remains unclear. In order to get a complete view, the students at ASP analysed the phenomenon through both an experimental campaign and using computational models.

They designed a micro-compression device that both tests femoral bone samples under conditions that reproduce the in-vivo working conditions inside the human body and acquires images of specific bone sections. This was made possible by the use of innovative technology, based on the generation of synchrotron light and high-quality free-electron lasers, at Elettra Sincrotrone in Trieste. Synchrotron light is a form of electromagnetic radiation characterised by charged particles moving at a very high velocity, close to the speed of light, and which consequently has a very short wavelength. These characteristics mean that the radiation peak falls within the range of X-rays and is very suitable for analysing tissue such as bone. This is the key point of the research, because, up until now, no one had ever studied bone lacunae with such high-resolution images. Indeed, the strength of this research is precisely the quality and quantity of images acquired and analysed.

Equally innovative was the technique used to process this large amount of data. Having to examine over 2 million images, the students decided to automate the process by developing a convolutional neural network capable of autonomously identifying bone lacunae. Neural networks are deep learning algorithms that are now the focus of attention in the international scientific community because of their potential in analysing clinical images. This algorithm saved more than 2 million hours in the post-processing phase. At the same time, the students also examined bone lacunae using computational simulations. They developed and validated a model that reproduces bone compression tests that can be used for future analyses without the need for new bone samples.

The GAP project, coordinated by Maria Chiara Sbarra, together with Irene Aiazzi, Bingji Liu, Alessandro Casto and Giovanni Ziarelli, has achieved important results in just two years of work. The multidisciplinary team, led by Professor Laura Vergani and PhD student Federica Buccino from the Department of Mechanics at the Politecnico di Milano, collaborated with ETH Zurich, the Elettra Sincrotrone international research centre in Trieste and the San Donato Group.

More efficient perovskite-based solar cells thanks to supramolecular chemistry

Posted on 24/03/202206/08/2024 by Erik Franco

Supramolecular chemistry (which deals with multimolecular systems), and in particular halogen bonding, i.e., the intermolecular interaction involving halogen atoms (I, Br and Cl) in organic molecules, can help improve the performance of perovskite-based solar cells, enabling them to achieve high levels of efficiency and high stability.

This is the conclusion of researchers at the Politecnico di Milano who have published in the prestigious Angewandte Chemie International Edition.

Organic-inorganic hybrid perovskites – ionic compounds consisting of small organic cations and metal halides – have been known about since the 19th century, but they have only recently been used in optoelectronics for the construction of lasers, diodes, photodetectors and solar cells. In particular, the first perovskite-based photovoltaic cell was produced in 2009 and since then there has been intensive research into achieving an efficiency of more than 25%, which would surpass even the silicon that currently dominates the photovoltaic market.

The low cost and excellent performance of perovskites make them very attractive for photovoltaic applications, but there are still a number of problems that prevent these materials from entering the market. First of all, there is their low stability when it comes to air and humidity. In addition, the presence of defects, i.e., imperfections in the crystal lattice, can generate ‘trap states’ that interfere with the movement of charge carriers (electrons and holes) generated by light within the material, trapping them and causing electrical energy losses. Generally, these trap states are unbound halide ions that can move under the effect of an electric field and recombine with holes.

The study conducted at the Politecnico showed that the use of additives capable of forming halogen bonds with the halide ions present in perovskites provides significant advantages for the development of solar cells with better crystallinity and greater stability. Halogen bonding enables fluorinated molecules to be introduced, which passivate the surface halides to produce hydrophobic and water-repellent perovskites. In this way, trap states are blocked and efficiency is increased.

In addition, the surface modification of perovskite with bifunctional molecules capable of forming halogen bonds enables better integration of the perovskite within the solar cell, facilitating the generation of electrical current.

From the data reported, it appears that halogen bonding has considerable potential for the development of a new generation of solar cells based on perovskites. However, a better atomic/molecular understanding of these materials is needed to fully exploit the advantages of halogen bonding.

The paper was written by Gabriella Cavallo, Giancarlo Terraneo and Pierangelo Metrangolo of the Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’ of the Politecnico di Milano in collaboration with Laura Canil and Antonio Abate (an alumnus of the Politecnico di Milano) of the Helmholtz Zentrum Berlin fur Materialen und Energie.

Read the paper on Angewandte Chemie International Edition

ERC Consolidator Grant to Sara Bagherifard’s ArcHIDep project

Posted on 18/03/202206/08/2024 by Erik Franco

The European Research Council (ERC), the European Union organization that rewards talented scholars engaged in cutting-edge research, is funding Sara Bagherifard‘s project ArcHIDep. The research project was selected from among more than 2,000 proposals received by ERC.This is a great result for the Politecnico, considering that this year only 11.8% of the projects submitted have obtained funding. In addition to this project, to date, a total of 49 ERC grants have been awarded to researchers from the Politecnico di Milano.

Sara Bagherifard, senior researcher in the Department of Mechanical Engineering at the Politecnico di Milano, will work on the ArcHIDep project: a revolutionary system of solid-state deposition to obtain heterogeneous materials with structured architecture on three scales: micro, meso and macro.

This ambitious goal is possible with the development of the cold spray beyond the state of the art, with analytical models, experimental tests and multi-scale computational models.

ArcHIDep will develop a framework, currently non-existent, that will allow the design and construction of elements capable of overcoming the limits connected to the current impossibility of combining conflicting properties, by the rational exploitation of raw materials and superior performance.

ERC Consolidator Grants are intended for researchers with at least 7 years of experience since obtaining their PhD and with a very promising scientific profile. These are scholars who aim to consolidate their independence in research, strengthening their research group and continuing to develop a career in Europe. Funding can reach €2 million per single project, for a maximum duration of 5 years.

ERC Consolidator Grants to Massimo Tavoni’s EUNICE project

Posted on 17/03/202206/08/2024 by Erik Franco

The European Research Council (ERC), the European Union organization that rewards talented scholars engaged in innovative research, is funding EUNICE, a project led by Prof. Massimo Tavoni from the Politecnico di Milano. The research project was selected from among more than 2,000 proposals received by ERC.This is a great result for the Politecnico, considering that this year only 11.8% of the projects submitted have obtained funding. In addition to these two projects, to date, a total of 49 ERC grants have been awarded to researchers from the Politecnico di Milano.

Massimo Tavoni, Professor of Engineering for the Environment and the Territory, has been awarded the grant for EUNICE, which aspires to correct the errors of the ensembles of climate-energy-economy models that study climate stabilization, and to develop methods to validate and confirm the intuitions of the scenarios.

The objective of the project is therefore to develop an innovative and integrated approach to quantify, translate, and communicate in an effective and timely manner the main uncertainties associated with low-carbon pathways and scenarios that explore very distant futures, renewing the methodological and experimental bases of model-based climate assessments.

EUNICE is a project of great relevance also for other research areas: the approach and innovations developed by EUNICE can in fact also be applied to other high-risk environmental, social, and technological assessments.

Its unique combination of computational and behavioural science and public engagement will be an important mediation tool in debates on fundamental decisions for our society, increasing confidence in and recognition of the scientific method.

Controlling how fast graphene cools down

Posted on 09/03/202206/08/2024 by Erik Franco

Graphene is the thinnest material ever produced, with the thickness of a single atomic layer, thinner than a billionth of a meter.

A property of its is to efficiently absorb light from the visible to the infrared through the photoexcitation of its charge carriers. After light absorption, its photoexcited charge carriers cool down to the initial equilibrium state in a few picoseconds, corresponding to a millionth of a millionth of a second. The remarkable speed of this relaxation process makes graphene particularly promising for a number of technological applications, including light detectors, sources and modulators.

A recent study published in ACS Nano has shown that the relaxation time of graphene charge carriers can be significantly modified by applying an external electrical field. The research was conceived within an international collaboration between the CNR-IFN, Politecnico di Milano, the University of Pisa, the Graphene Center of Cambridge (UK) and ICN2 of Barcelona (Spain), and it is supported by the European project Graphene Flagship.

This work paves the way to the development of devices that exploit the control of the relaxation time of charge carriers to support novel functionalities. For example, if graphene is used as saturable absorber in a laser cavity to generate ultrashort light pulses, by changing the relaxation time of the charge carriers, we can control the duration of the output pulses.

The theoretical modeling of the relaxation of the charge carriers of graphene as a function of the external electric field has allowed the identification of the physical mechanism underlying the observed phenomenon. The graphene-based device has been studied by ultrafast spectroscopy, which allowed to monitor the variation of the relaxation time of the charge carriers.

This discovery is of large interest for a number of technological applications, ranging from photonics, for pulsed laser sources or optical limiters that prevent optical components damaging, to telecommunication, for ultrafast detectors and modulators
Giulio Cerullo, professor of the Department of Physics of Politecnico di Milano

The research on ACS Nano

Discovery of a new phase transition in quasi-crystals

Posted on 07/03/202206/08/2024 by Erik Franco

A team of researchers from the Politecnico di Milano and the University of Rostock (Germany) has discovered and observed in the laboratory a new type of phase transition in a quasi-crystal made of laser light.

The discovery of this new phase transition in quasi-crystals represents a breakthrough in the understanding of some fundamental phenomena of quantum matter.

Quasi-crystals are structures that are not perfectly ordered, like crystals, but not completely disordered and are among the rarest structures in nature. In order to study their characteristics, the team of experimental physicists made in the laboratory a quasi-crystal with laser light that propagates in an intertwined manner in kilometre-long optical fibres: the complex dynamics of light in these fibres closely mirrors the quantum motion of electrons in the quasi-crystal. During the experiment, the researchers observed a triple phase transition, in which the topological properties, conductivity, and energy exchange between the quasi-crystal and its surroundings change abruptly but at the exact same time.

The discovery was published in the journal Nature and could pave the way for a holistic understanding of the inner workings of complex or engineered materials and their use in advanced phase-controlled materials-based applications.

The discovery of this new phase transition in quasi-crystals represents a breakthrough in the understanding of some fundamental phenomena of quantum matter. It may also pave the way for the development of a new technology and type of material unlike anything we have seen before, the properties of which we will be able to simultaneously control and modify at will. It would be a new form of matter much more flexible and controllable than the one we currently know about.
Stefano Longhi, professor at the Department of Physics of the Politecnico and co-author of the study

The article published in Nature

Hybris: structural batteries for electric aircraft

Posted on 04/03/202206/08/2024 by Erik Franco

Hybris is developed by a research group consisting of professors and students of the Department of Aerospace Science and Technology of the Politecnico di Milano.

It is the design of a hybrid-electric aircraft with structural batteries.

Structural batteries are innovative multifunctional composite materials that can withstand mechanical loads while simultaneously storing electrical energy. Both the fuselage and the outside of the wings of the HYBRIS are made of structural batteries.

The inventors are Andrea Bernasconi, Fabio Biondani, Luca Capoferri, Alberto Favier, Federico Gualdoni, Carlo Riboldi, Lorenzo Trainelli, Carmen Velarde Lopez de Ayala

Hybris won the Intellectual Property Award (IPA) in the “aerospace” sector, as announced at the Italian Pavilion of Expo Dubai. It is the competition for Italian technological patents resulting from public research organised by the Ministry of Economic Development in collaboration with Netval (Network for Research Valorisation).

A total of 217 innovative patents developed by Universities, Research Centres and Scientific Hospitalisation and Treatment Institutions were considered for the competition; and 35 of these were selected for the final stage in Dubai.

At the end of the process, the award-winning projects were those able to propose innovations with the greatest economic and social impact in 7 technological areas of reference for the global ecological and digital transition: agritech and agrifood, cybersecurity, green tech, life science, future mobility, aerospace, and alternative energy.