Research will be carried out jointly with the American counterparts in the different scientific fields, with work on a wide range of projects: from the study of coastal rock shaping, to the conservation of the biodiversity of the ecosystems; from new materials of particular technological interest to the analysis of the reaction of masonry walls under seismic action. The evaluation of the projects presented in the second call of the MIT-UNIPI agreement sealed in 2012 and aimed at promoting new collaboration in research between the University of Pisa and Massachusetts Institute of Technology in Boston has now been concluded. Four of the eleven proposals put forward have been chosen for funding by the Advisory Board and these join the five previous projects chosen last July.
The winners are Marta Pappalardo from the Department of Earth Sciences, with the project "Assessing the effect of Biota on coastal Rock Surface", Lisandro Benedetti Cecchi from the Department of Biology, "Critical Slowing Down and Early Warning Indicators of Regime Shifts", Valentina Domenici from the Department of Chemistry, "Energy Storage Devices and Actuators based on Composites of Liquid Crystal Elastometers" and Riccardo Barsotti from the Department of Civil and Industrial Engineering, "Mechanical Models for Masonry Walls under Seismic Action". The projects will be carried out in collaboration with a PI (Principal Investigator) from MIT and the activities will take place from January 2014 to August 2015.
For the University of Pisa this collaboration with MIT is of considerable importance due to the prestigious reputation of the American institute which is considered universally to be at the apex of scientific research. In Italy MIT had previously only collaborated actively with the Polytechnic Institutes of Milan and Turin: Pisa is therefore the first non-specialized Italian university to have undertaken a partnership of a broader nature. The three-year convention will cover all the scientific fields with priority given to the sectors of Energy, Information and Communication Technologies and Life Sciences which relate directly to three of the Tuscan technological districts. The MIT-UNIPI project was born with the aim of fostering cooperation between researchers and teaching staff from MIT and the University of Pisa on new and advanced projects.
The projects
«Assessing the effect of Biota on coastal Rock Surface»
Marta Pappalardo
The diverse landforms of coastal areas are affected by the activity of sessile biota such as mussel and barnacle. While their amount and species are known to be sensitive to environmental change, it is not clear how they are able to shape coastal landform. Lack of such the knowledge prevents us from understanding the significance of the impact of biota on the long term evolution of coastal landform. Here we propose to combine a materials and environmental science approach at the intersection of mechanics and biology, and hypothesize that the activity of sessile biota alters the surface property of coastal rock by changing its mechanical strength and chemical composition. This project brings together experimental and computational efforts to quantify those effects as well as to understand their mechanism. We hypothesize that bioerosion occurs at the interface between biota and coastal rock and cause the rock surface to lose its strength, which couples with wave erosion to shape landforms. Our results can be used to quantify the effect of biota on coastal landforms, which are important for environmental policies and life design of construction in coastal areas, and provide complementary advances in biology and engineering. Our project involves the exchange of students and scientific experimentation, and will strengthen the ties between MIT and Unipi and open opportunities for future funding. The materials science point of view coupled with structural mechanics introduces a mechanistic approach to explain a crucial environmental effect that can have broad implications on the ecology of sessile biota.
«Critical Slowing Down and Early Warning Indicators of Regime Shifts»
Lisandro Benedetti Cecchi
Anticipating regime shifts in complex systems is important given the potential impacts that these transitions may have on humanity. Recovery from small perturbations decreases close to a critical threshold in these systems, a phenomenon known as critical slowing down. Perturbation experiments with microbial populations have supported this hypothesis under controlled laboratory conditions, but evidence from real ecosystems remains rare. We will use rocky intertidal communities of algae and invertebrates with well characterized alternative states as a model system to provide an experimental test of critical slowing down in naturally fluctuating environments. We will implement canopy perturbation experiments using a design similar to that employed in laboratory tests of critical slowing down, to test the hypothesis that recovery in space will decrease as the system approaches the tipping point separating a canopy-dominated from a turf-dominated community. Showing that advance warning of critical thresholds is achievable in real ecosystems is necessary before we can confidently apply the proposed early warning indicators of regime shifts in environmental conservation and management.
«Energy Storage Devices and Actuators based on Composites of Liquid Crystal Elastometers»
Valentina Domenici
Liquid Crystalline Elastomers (LCEs), also known as "artificial muscles" or "shape memory" actuators can undergo controlled shape changes in response to external stimuli. Some well-known examples include nematic polysiloxane-based LCE thin films, which contracts with increasing temperature, and LCEs doped or chemically modified with azobenzene derivatives, which reversibly expands/contracts with the application of UV-vis light at specific wavelengths. However, few examples exist in which LCE films change shape in response to the application of an external voltage or controlled current; in all known cases, voltage or current-responsive LCE systems are doped with nanoparticles or covered by conductive layers. The mechanism of functioning of these bilayered films or composite films is currently not understood. Furthermore, while changes in chemistry at the interface between the "soft" liquid crystalline phase and the conductive or electro-active material can affect the response, the molecular phenomena governing this behavior are unknown. In the proposed project, we will use a combination of closely coupled experimental (spectroscopic and electrochemical methods) and computational techniques to develop a fundamental understanding of the role of interface structure and chemistry in determining the micro and macroscopic properties of a range of functionalized LCEs coated with conductive polymers or metal oxide thin films. The project proposed by Valentina Domenici (UNIPI, Pisa), who is expert on LCE materials, and Alexei Kolpak and Yang Shao-Horn (MIT, Boston) focuses on the chemical-physical study of the interface between these double-layered systems. The results from this project will enable rational design of novel LCE-based functional materials with tailored properties that may be used in a wide range of applications, such as energy conversion and storage micro-systems and micro-actuators.
«Mechanical Models for Masonry Walls under Seismic Action»
Riccardo Barsotti
Masonry structures represent the great majority of the architectural heritage of European countries. The conservation and restoration of this heritage calls for proper assessment of the actual conditions and structural capacity of masonry structures. As is well known, such problems are not straightforward to solve, and no general solution method is available at present. In this research we will focus on analyzing the mechanical response of historical masonry walls under in-plane or out-of-plane actions, both vertical (dead or live loads) and horizontal (seismic actions). Both limit analysis and nonlinear elastic models will be used. The influence of the main geometrical parameters (unit type and size, texture, number of leaf, etc.) will be studied, highlighting the role played by each parameter. 
Our intention is to check whether simple structural models can provide useful indications for the basic case of a masonry panel. Based on such indications, a mechanical model describing a masonry wall can be formulated, thus allowing for the analysis of a whole masonry construction utilizing both analytical and numerical methods. This can provide both a sensitivity analyses as well as a comparison between the numerical and analytical solutions. To achieve this goal, both the finite element (FEM) and the discrete element methods (DEM) will be employed. In particular, DEM could be used for the dynamic analysis of masonry panels viewed as an assemblage of blocks. A comparison with the numerical and experimental results available in the literature will then be performed.