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Barrier layers against intermetallic diffusion are a fundamental part on engineering electroplated coatings as they improve the lifetime of goods reducing wastes and improving the sustainability of the production chain. This study aims to set a cost-effective methodology to characterize barrier systems by evaluating the effectiveness with a recent approach based on XRF and EDS and characterize the kinetic of diffusion processes with X-ray diffractometry. Several high fashion barrier systems were tested highlighting that anticorrosion systems are not automatically suited as barrier layers for intermetallic diffusion, as opposed to industrial practice. Investigations on gold coatings obtained varying the current density revealed a correlation between the activation energy of the diffusion process, roughness, and crystallite size.

Summary: In this high-risk/high-reward study, we prepared complexes of a high explosive anion (picrate) with potentially explosive s-tetrazine-based ligands with the sole purpose of advancing the understanding of one of the weakest supramolecular forces: the lone pair-π interaction. This is a proof-of-concept study showing how lone pair-π contacts can be effectively used in crystal engineering, even of high explosives, and how the supramolecular architecture of the resulting crystalline phases influences their experimental thermokinetic properties. Herein we present XRD structures of 4 novel detonating compounds, all showcasing lone pair-π interactions, their thermal characterization (DSC, TGA), including the correlation of experimental thermokinetic parameters with crystal packing, and in silico explosion properties. This last aspect is relevant for improving the safety of high-energy materials.

The study of marine Lagrangian transport holds significant importance from a scientific perspective as well as for practical applications such as environmental-pollution responses and prevention (e.g., oil spills, dispersion/accumulation of plastic debris, etc.). In this regard, this concept paper introduces the Smart Drifter Cluster: an innovative approach that leverages modern “consumer” IoT technologies and notions. This approach enables the remote acquisition of information on Lagrangian transport and important ocean variables, similar to standard drifters. However, it offers potential benefits such as reduced hardware costs, minimal maintenance expenses, and significantly lower power consumption compared to systems relying on independent drifters with satellite communication. By combining low power consumption with an optimized, compact integrated marine photovoltaic system, the drifters achieve unlimited operational autonomy. With the introduction of these new characteristics, the Smart Drifter Cluster goes beyond its primary function of mesoscale monitoring of marine currents. It becomes readily applicable to numerous civil applications, including recovering individuals and materials at sea, addressing pollutant spills, and tracking the dispersion of marine litter. An additional advantage of this remote monitoring and sensing system is its open-source hardware and software architecture. This fosters a citizen-science approach, enabling citizens to replicate, utilize, and contribute to the improvement of the system. Thus, within certain constraints of procedures and protocols, citizens can actively contribute to the generation of valuable data in this critical field.

Robotic devices are being employed in more and more sectors to enhance, streamline, and augment the outcomes of a wide variety of human activities. Wearable robots arise indeed as of-vital-importance tools for telerehabilitation or home assistance targeting people affected by motor disabilities. In particular, the field of “Robotics for Medicine and Healthcare” is attracting growing interest. The development of such devices is a primarily addressed topic since the increasing number of people in need of rehabilitation or assistive therapies (due to population aging) growingly weighs on the healthcare systems of the nation. Besides, the necessity to move to clinics represents an additional logistic burden for patients and their families. Among the various body parts, the hand is specially investigated since it most ensures the independence of an individual, and thus, the restoration of its dexterity is considered a high priority. In this study, the authors present the development of a fully wearable, portable, and tailor-made hand exoskeleton designed for both home assistance and telerehabilitation. Its purpose is either to assist patients during activities of daily living by running a real-time intention detection algorithm or to be used for remotely supervised or unsupervised rehabilitation sessions by performing exercises preset by therapists. Throughout the mechatronic design process, special attention has been paid to the complete wearability and comfort of the system to produce a user-friendly device capable of assisting people in their daily life or enabling recorded home rehabilitation sessions allowing the therapist to monitor the state evolution of the patient. Such a hand exoskeleton system has been designed, manufactured, and preliminarily tested on a subject affected by spinal muscular atrophy, and some results are reported at the end of the article.

Riders’ asymmetry may cause back pain in both human and equine athletes. This pilot study aimed at documenting in a simple and quick way asymmetry in riders during a simulation of three different riding positions on wooden horseback using load cells applied on the stirrup leathers and identifying possible associations between riders’ asymmetry and their gender, age, level of riding ability, years of riding experience, riding style, motivation of riding, primary discipline and handedness. After completing an interview to obtain the previously mentioned information, 147 riders performed a standardized test on a saddle fixed on a wooden horseback-shaped model. The riding simulation was split into three phases of 1 min each: (1) sit in the saddle, (2) standing in the stirrups and (3) rising trot. The directional force on the left and the right stirrup leathers was recorded every 0.2 s. A paired t-test was performed on the recorded data to test the difference (i.e., asymmetry) in each phase. In phases 1, 2 and 3, 99.3% (53.4% heavier on the right (R)), 98% (52.8% heavier on the left (L)) and 46.3% (51.5% heavier on the left (L)) of the riders were asymmetrical, respectively. Chi-square tests showed a significant association between riding ability and riding experience, but no significant association between reported handedness and calculated leg-sidedness (p > 0.05). Univariate logistic (1: asymmetry, 0: symmetry) regression analysis was performed only on the phase 3 data. One-hand riders were found twice more likely to be asymmetrical than two-hand riders (Odds Ratio (OR): 2.18, Confidence Interval (CI): 1.1–4.29; p = 0.024). This preliminary study confirmed that the majority of the riders are asymmetrical in load distribution on stirrups and suggested the riding style as a possible risk factor for asymmetry.

Since the development of the first autonomous underwater vehicles, the demanded tasks for subsea operations have become more and more challenging as, for instance, intervention, maintenance and repair of seabed installations, in addition to surveys. As a result, the development of autonomous underwater reconfigurable vehicles (AURVs) with the capability of interacting with the surrounding environment and autonomously changing the configuration, according to the task at hand, can represent a real breakthrough in underwater system technologies. Driven by these considerations, an innovative AURV has been designed by the Department of Industrial Engineering of the University of Florence (named as UNIFI DIEF AURV), capable of efficiently reconfiguring its shape according to the task at hand. In particular, the UNIFI DIEF AURV has been provided with two extreme configurations: a slender (“survey”) configuration for long navigation tasks, and a stocky (“hovering”) configuration designed for challenging goals as intervention operations. In order to observe the several dynamic features for the two different configurations, a novel formulation for the dynamic maneuverability analysis (DMA) of an AURV, adapting Yoshikawa’s well-known manipulability theory for robotic arms, is proposed in this work. More specifically, we introduce a novel analysis which relates the vehicle body-fixed accelerations with the rotational speed of each thruster, taking into account also the AURV dynamic model for each configuration and the propulsion system.

The knowledge of the adsorption geometry of an analyte on a metal substrate employed in surface enhanced Raman scattering (SERS) spectroscopy is important information for the correct interpretation of experimental data. The adsorption geometry of alizarin on silver nanoparticles was studied through ab initio calculations in the framework of density functional theory (DFT) by modeling alizarin taking into account all the different charged species present in solution as a function of pH. The calculations allowed a faithful reproduction of the measured SERS spectra and to elucidate the adsorption geometry of this dye on the silver substrate.

This paper describes design methods for the plastic hull of an Unmanned Underwater Vehicle (UUV), with a particular focus on its cylindrical body and nearly spherical domes at the ends. With the proposed approach, the methodologies reported in the literature were compared, and suitable modifications and improvements were investigated and implemented to extend the classical theories and data to this case study. The investigated underwater vehicle, named FeelHippo, was designed and assembled by the Department of Industrial Engineering of the University of Florence. Its main hull is composed of an extruded PMMA (PolyMethyl MethAcrylate) cylinder and two thermoformed PMMA domes. Breakage of the hull results in destructive phenomena, namely, yielding and buckling. An experimental campaign and FEM (Finite Element Method) analysis were carried out to complete the theoretical study, and the collapse pressures were compared with the derived design values. In conclusion, the proposed innovative method is a lean and effective technique for designing underwater hull domes and predicting the collapse pressures.

Di(oxymethylene)glycol forms in formaldehydeaqueous solutionsby polymerization of methanediol. The structure and hydrogen bondinteractions of di(oxymethylene)glycol with water were characterizedby performing Car–Parrinello molecular dynamics simulations.The anharmonic vibrational frequencies of di(oxymethylene)glycol insolution were determined with ab initio calculations considering explicitlythe hydrogen-bonded water molecules, while other interactions withsolvent were described within a polarizable continuum model approach.The calculations allow for a detailed interpretation of the experimentalRaman spectrum of formaldehyde aqueous solutions, leading to the assignmentof the band at 920 cm–1to the symmetric CO stretchingmode of di(oxymethylene)glycol. [ABSTRACT FROM AUTHOR]

Cuprizone (oxalic acid bis(cyclohexylidene hydrazide)) is a potent neurotoxin that is known to induce the destruction of the myelinic sheath which covers the cells of the central nervous system (CNS). The mechanism of action has not yet been elucidated due to lack of structural information. We have performed an ab initio prediction of the molecular structure by high-level quantum chemical methods, leading to two possible conformers of a nearly identical energy: A, for which an analysis of the electron density distribution shows more propensity for intermolecular bonding, and B, with stronger intramolecular liaison. Having obtained suitable single crystals, we report a detailed study of the crystal and molecular structure, which reveals that the molecular and crystal centers of symmetry coincide, and that the actual conformer is A, as expected, and in agreement with the ab initio prediction. Further information is gained by optimization of the crystal structure by Car-Parrinello molecular dynamics, yielding good agreement with observation. Infrared and Raman spectra show mutual exclusion, suggesting a centrosymmetric molecule with carbonylic bonds in trans configuration; moreover, vibrational frequencies calculated ab initio also show excellent agreement with observations. We thus present a multi-technique approach to the prediction and interpretation of various aspects of the complex interplay between intra- and intermolecular forces. [ABSTRACT FROM AUTHOR]

A Car−Parrinello molecular dynamics simulation has been performed on a solution of Br-in liquid methanol analyzing with particular attention charge transfer and polarization effects. The first solvation shell has been characterized in terms of H-bonds, and it has been found that the high polarization of the bromide gives rise to a stable solvent cage. The differences in the coordination number with the chloride can be ascribed to the ionic radius and to the stronger perturbations brought by the solvent to the bromide ion. [ABSTRACT FROM AUTHOR]

When the free energy surface of the lithium hydroxide monohydrate crystal was explored, the high-pressure solid-state phase transition was determined. The high-pressure phase has been obtained through ab initio Car−Parrinello molecular dynamics simulation in the isothermic−isobaric ensemble. The recent metadynamics method has been applied to overcome the high activation energy barriers typical of rare events, like solid-state phase transition at high pressures. In the LiOH·H2O system, there are two kinds of H bonds:  water−water and hydroxyl−water. The effect of the pressure has been investigated, to give further insight into the high-pressure phase. The strengthening of the H bonds of the system produces modifications in the water and the hydroxyl ion dipole electronic environment. The infrared spectra of both phases have been calculated and compared with experiments, and the assignment of the external modes has been discussed. [ABSTRACT FROM AUTHOR]