A Bioinspired Plasmonic Nanocomposite Actuator Sunlight-Driven by a Photothermal-Hygroscopic Effect for Sustainable Soft Robotics

Combined photothermal-hygroscopic effects enable novel materials actuation strategies based on renewable and sustainable energy sources such as sunlight. Plasmonic nanoparticles have gained considerable interest as photothermal agents, however, the employment in sunlight-driven photothermal-hygroscopic actuators is still bounded, mainly due to the limited absorbance once integrated into nanocomposite actuators and the restricted plasmonic peaks amplitude (compared to the solar spectrum). Herein, the design and fabrication of an AgNPs-based plasmonic photothermal-hygroscopic actuator integrated with printed cellulose tracks are reported (bioinspired to Geraniaceae seeds structures). The nanocomposite is actuated by sunlight power density (i.e., 1 Sun = 100 mW cm−2). The plasmonic AgNPs are in situ synthesized on the PDMS surface through a one-step and efficient fluoride-assisted synthesis (surface coverage ≈40%). The nanocomposite has a broadband absorbance in the VIS range (>1) and a Photothermal Conversion Efficiency ≈40%. The actuator is designed exploiting a mechanical model that predicted the curvature and forces, featuring a ≈6.8 ± 0.3 s response time, associated with a ≈43% change in curvature and a 0.76 ± 0.02 mN force under 1 Sun irradiation. The plasmonic nanocomposite actuator can be used for multiple tasks, as hinted through illustrative soft robotics demonstrators, thus fostering a bioinspired approach to developing embodied energy systems driven by sunlight

A plant-inspired robot with soft differential bending capabilities

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Image-based Approach to Reconstruct Curling in Continuum Structures

This paper proposes an image-based approach to reconstruct the shape of continuum biological (e.g., tendrils of climbing plants) and artificial (continuum soft robots) structures which can deform into coils or curls with variable curvature that depends on the arc length. The proposed method is based on 2D clothoid curves, for which we explore two resolution approaches: i) single-segment clothoid representation, with optimal curve parameters search; ii) piece-wise clothoid representation, with G 1 Hermite-fitting solution. Besides, we propose a novel algorithm to sort 2D unarranged points that addresses the issue of possible undesired branches and discontinuities. We numerically evaluate the performance of the method and compare it with a constant curvature fitting. We obtain an improvement of more than 100% in tendril and up to 5% with a soft continuum robotic artefact, demonstrating the feasibility and the reliability of our approach. The proposed model can be applied for shape representation and reconstruction on both long slender living organisms and continuum soft robots with curling-like behavior

HyLength: a semi-automated digital image analysis tool for measuring the length of roots and fungal hyphae of dense mycelia

In plant-fungus phenotyping, determining fungal hyphal and plant root lengths by digital image analysis can reduce labour and increase data reproducibility. However, the degree of software sophistication is often prohibitive and manual measuring is still used, despite being very time-consuming. We developed the HyLength tool for measuring the lengths of hyphae and roots in in vivo and in vitro systems. The HyLength was successfully validated against manual measures of roots and fungal hyphae obtained from all systems. Compared with manual methods, the HyLength underestimated Medicago sativa roots in the in vivo system and Rhizophagus irregularis hyphae in the in vitro system by about 12 cm per m and allowed to save about 1 h for a single experimental unit. As regards hyphae of R. irregularis in the in vivo system, the HyLength overestimated the length by about 21 cm per m compared with manual measures, but time saving was up to 20.5 h per single experimental unit. Finally, with hyphae of Aspergillus oryzae, the underestimation was about 8 cm per m with a time saving of about 10 min for a single germinating spore. By benchmarking the HyLength against the AnaMorf plugin of the ImageJ/Fiji, we found that the HyLength performed better for dense fungal hyphae, also strongly reducing the measuring time. The HyLength can allow measuring the length over a whole experimental unit, eliminating the error due to sub-area selection by the user and allowing processing a high number of samples. Therefore, we propose the HyLength as a useful freeware tool for measuring fungal hyphae of dense mycelia

Mechanics and optimization of undulatory locomotion in different environments, tuning geometry, stiffness, damping and frictional anisotropy

This video shows the behavior of polychaete-like locomotio

Towards the optimization of passive undulatory locomotion on land: mathematical and physical models

The current study investigates the body–environment interaction and exploits the passive viscoelastic properties of the body to perform undulatory locomotion. The investigations are carried out using a mathematical model based on a dry frictional environment, and the results are compared with the performance obtained using a physical model. The physical robot is a wheel-based modular system with flexible joints moving on different substrates. The influence of the spatial distribution of body stiffness on speed performance is also investigated. Our results suggest that the environment affects the performance of undulatory locomotion based on the distribution of body stiffness. While stiffness may vary with the environment, we have established a qualitative constitutive law that holds across environments. Specifically, we expect the stiffness distribution to exhibit either an ascending–descending or an ascending–plateau pattern along the length of the object, from head to tail. Furthermore, undulatory locomotion showed sensitivity to contact mechanics: solid–solid or solid–viscoelastic contact produced different locomotion kinematics. Our results elucidate how terrestrial limbless animals achieve undulatory locomotion performance by exploiting the passive properties of the environment and the body. Application of the results obtained may lead to better performing long-segmented robots that exploit the suitability of passive body dynamics and the properties of the environment in which they need to move

Eretici e libertari. Il movimento anarchico in Italia (1945-1973)

Heri dicebamus. After the Resistance, the anarchists took up the thread of their revolutionary discourse in the new Italian political and social context. Decimated during the long struggle against fascism, defeated in the Spanish war, powerless spectators of the Bolshevization of the labor movement, the old militants began the hard transition from being protagonists within mass politics in the first half of twentieth century to becoming its observers. The movement was regenerated as a kind of “neo-anarchism”, by way of cultural contamination with the heretical left of the 50’s, through the libertarian movements of the following decade. Four main issues characterized the history of anarchism in Republican Italy: the new political actor FAI, anarcho-syndicalism, the international dimension, 1968

Il potere dell’architettura. L’ideologia di regime all’Esposizione Internazionale di Parigi 1937

The political crackdown during the 20th Century finds in the International Events a special place for the hosting Countries to spread their ideologies to the visitors and to all the other Countries attending the event. National Pavilions become the subject of propaganda, and their architectural language became an important part of the collective identity’s reclaimed logic, even if it wasn’t always real. Paris International Exposition of 1937 is a paradigmatic case: it’s a mirror of that time and of the prewar period’s international tensions. Born under the auspices of peace, it finally results the most relevant expression of the relation between Power and Architecture

L’Esposizione del Sempione 1906. Milano in vetrina

Milan wanted to take on the project of an International Exhibition although it was unrelated to the overblown expositive approach. By studying the archival documents and analyzing contemporaneous publishings, this paper meant to show how the 1906’s fair allowed Milan to demonstrate his ability and capability as well as to represent a peaceful competition with other foreign economic realities. In order to ensure a successful event, the establishment has striven to expose the modern and cosmopolitan face of Milan, inside and outside the “white city”

L’Italia alla periferia del Mediterraneo. Le relazioni italo-spagnole tra XIX e XX secolo : politica, economia e società

La nascita del Regno d’Italia contribuì a cambiare notevolmente le relazioni politicoeconomiche all’interno dell’Europa del XIX secolo. Paesi come Gran Bretagna, Francia o Germania dovettero considerare la presenza del modesto stato meridionale, soprattutto nell’ottica di future espansioni nell’arco del Mediterraneo. Da parte sua, la Spagna – coinvolta in una grave e secolare decadenza politica – non poté far a meno che dirigere la sua attenzione verso il vicino e storico “cugino” linguistico. Nonostante un inizio difficoltoso, le relazioni tra i due paesi si trasformarono in un continuo interscambio di accordi, trattati e proposte culturali. L’avvicinamento della Spagna durante la prima metà del XX secolo, fu consolidata anche dall’inarrestabile ascesa del fascismo italiano che contribuirà – durante il conflitto civile spagnolo – alla nascita non solo di un “fascismo spagnolo” ma di un vero e proprio stato dittatoriale governato dall’«amico» Francisco Franco