Design of a hydraulic servo-actuation fed by a regenerative braking system

Many conventional truck and working machines are equipped with additional hydraulic tooling or manipulation systems which are usually fed through a mechanical connection with the internal combustion engine, involving a poor efficiency. In particular, this is a common situation for industrial vehicles whose mission profiles involves a relevant consumption of energy by the on board hydraulic systems, respect to the one really needed for only traction purpose. In this work it is proposed an innovative solution based on the adoption of a system aimed to recover braking energy in order to feed an efficient on board hydraulic actuation system. The proposed system is then adopted to a real application, an Isuzu truck equipped with a hydraulic tooling for garbage collection. A prototype of the system has been designed, assembled and tested showing a relevant improvement of system efficiency and the feasibility of the proposed approach. In the paper the proposed solution is presented, showing the simulation models and preliminary validation results including experimental devices assembled to perform the tests

Computational Spectroscopy in Solution by Integration of Variational and Perturbative Approaches on Top of Clusterized Molecular Dynamics

Multiscale QM/MM approaches have become the most suitable and effective methods for the investigation of spectroscopic properties of medium-or large-size chromophores in condensed phases. On these grounds, we are developing a novel workflow aimed at improving the generality, reliability, and ease of use of the available tools. In the present paper, we report the latest developments of such an approach with specific reference to a general workplan starting with the addition of acetonitrile to the panel of solvents already available in the General Liquid Optimized Boundary (GLOB) model enforcing nonperiodic boundary conditions (NPBC). Next, the solvatochromic shifts induced by acetonitrile on both rigid (uracil and thymine) and flexible (thyrosine) chromophores have been studied introducing in our software a number of new features ranging from rigid-geometry NPBC molecular dynamics based on the quaternion formalism to a full integration of variational (ONIOM) and perturbative (perturbed matrix method (PMM)) approaches for describing different solute-solvent topologies and local fluctuations, respectively. Finally, thymine and uracil have been studied also in methanol to point out the generality of the computational strategy. While further developments are surely needed, the strengths of our integrated approach even in its present version are demonstrated by the accuracy of the results obtained by an unsupervised approach and coupled to a computational cost strongly reduced with respect to that of conventional QM/MM models without any appreciable accuracy deterioration

Enhancing the Accuracy of Ab Initio Molecular Dynamics by Fine Tuning of Effective Two-Body Interactions: Acetonitrile as a Test Case

Grimme’s dispersion-corrected density functional theory (DFT-D) methods have emerged among the most practical approaches to perform accurate quantum mechanical calculations on molecular systems ranging from small clusters to microscopic and mesoscopic samples, i.e., including hundreds or thousands of molecules. Moreover, DFT-D functionals can be easily integrated into popular ab initio molecular dynamics (MD) software packages to carry out first-principles condensed-phase simulations at an affordable computational cost. Here, starting from the well-established D3 version of the dispersion-correction term, we present a simple protocol to improve the accurate description of the intermolecular interactions of molecular clusters of growing size, considering acetonitrile as a test case. Optimization of the interaction energy was performed with reference to diffusion quantum Monte Carlo calculations, successfully reaching the same inherent accuracy of the latter (statistical error of ∼0.1 kcal/mol per molecule). The refined DFT-D3 model was then used to perform ab initio MD simulations of liquid acetonitrile, again showing significant improvements toward available experimental data with respect to the default correction

Development of an algorithm for assessing canopy volumes with terrestrial LiDAR to implement precision spraying in vineyards

Received: February 13th, 2021 ; Accepted: November 28th, 2021 ; Published: December 3rd, 2021 ; Correspondence: [email protected] spraying is one of the techniques for the reduction of pesticides use and it can help achieve the new European Green Deal standards. The aim of such technique is to apply the right amount of pesticides according to the target characteristics. The precision spraying implementation requires target volume assessment, which can be carried out by LiDAR sensors. Such technique requires complex and time-consuming procedures of canopy characteristics computing through post-processing points cloud reconstruction. The present work aimed to develop and test an algorithm through the use of a tractor-coupled with terrestrial LiDAR and GNSS technology in order to simplify the process. With the aim to evaluate the algorithm the LiDAR-based volume was correlated with two manual measurements of canopy volume (Tree Row Volume and Point Net Cloud). The results showed good correlations between manual and LiDAR measures both for total canopy volumes (R 2 = 0.67 and 0.56) and for partial canopy volume (R 2 = 0.74). In conclusion, although the LiDAR-based algorithm works in automatic mode, the canopy volumes approximation seems acceptable to estimate the canopy volumes, with the advantages of a swifter procedure and less laborious post-processing computations

Raman and Computational Study on the Adsorption of Xanthine on Silver Nanocolloids

Xanthine is a nucleobase, deriving from adenine and guanine by deamination and oxidation processes, which may deposit in the human body causing diseases, similar to uric acid. Here, we have investigated the adsorption of xanthine on silver colloidal nanoparticles by means of surface-enhanced Raman scattering (SERS) with an exciting radiation in the near-infrared spectral region, where interference due to fluorescence does not occur, along with density functional theory calculations of molecule/metal model systems. By adopting a combined experimental and computational approach, we have identified the "marker" SERS bands of xanthine and the tautomer that preferentially binds the silver particles, as well as the molecular group involved in the interaction with metal. This investigation allows using the FT-SERS spectroscopy for biosensory and diagnostic purposes in body fluids, detecting abnormal levels of xanthine, and preventing metabolic diseases