Repeated (4D) marine geophysical surveys as a tool for studying the coastal environment and ground-truthing remote-sensing observations and modeling

Sandy beaches and the nearshore environment are dynamic coastal systems characterized by sediment mobilization driven by alternating stormy and mild wave conditions. However, this natural behavior of beaches can be altered by coastal defense structures. Repeated surveys carried out with autonomous surface vehicles (ASVs) may represent an interesting tool for studying nearshore dynamics and testing the effects of mitigation strategies against erosion. We present a one-year experiment involving repeated stratigraphic and morpho-bathymetric surveys of a nearshore environment prone to coastal erosion along the Emilia-Romagna coast (NE Italy), the Lido di Dante beach, carried out between October 2020 and December 2021 using an ASV. Seafloor and subseafloor “snapshots” collected at different time intervals enabled us to delineate the seasonal variability and shed light on key controlling variables, which could be used to integrate and calibrate remote-sensing observations and modeling. The results demonstrated that repeated surveys could be successfully employed for monitoring coastal areas and represent a promising tool for studying coastal dynamics on a medium/short (years/months) timescale

Space and Time pattern of mid-velocity IMF emission in peripheral heavy-ion collisions at Fermi energies

The emission pattern in the V_perp - V_par plane of Intermediate Mass Fragments with Z=3-7 (IMF) has been studied in the collision 116Sn + 93Nb at 29.5 AMeV as a function of the Total Kinetic Energy Loss of the reaction. This pattern shows that for peripheral reactions most of IMF's are emitted at mid-velocity. Coulomb trajectory calculations demonstrate that these IMF's are produced in the early stages of the reaction and shed light on geometrical details of these emissions, suggesting that the IMF's originate both from the neck and the surface of the interacting nuclei.Comment: 4 pages, 3 figures, RevTex 3.1, submitted to Phys. Rev. Letter

Fiasco: a multidetector optimized for semiperipheral heavy ion collisions at Fermi energies

The Fiasco multidetector is a low-threshold apparatus, optimized for the investigation of peripheral to semi-central collisions in heavy ion reactions at Fermi energies. It consists of three types of detectors. The first detector layer is a shell of 24 position-sensitive Parallel Plate Avalanche Detectors (PPADs), covering about 70% of the forward hemisphere, which measure the velocity vectors of the heavy ðZ\10Þ reaction products. Below and around the grazing angle, behind the most forward PPADs, there are 96 DE–E silicon telescopes (with thickness of 200 and 500 mm; respectively); they are mainly used to measure the energy of the projectile-like fragment and to identify its charge and, via the time-of-flight of the PPADs, also its mass. Finally, behind most of the PPADs there are 158 (or 182, depending on the configuration) scintillation detectors, mostly of the phoswich type, which cover 25–30% of the forward hemisphere; they identify both light charged particles ðZ ¼ 1; 2Þ and intermediate mass fragments ð3pZt20Þ; measuring also their time-of-flight. r 2003 Elsevier B.V. All rights reserved

Batch pyrolysis of pellet made of biomass and crude glycerol: Mass and energy balances

Glycerol is a side-product of transesterification process, generated during the production of first generation biodiesel. From 10 t of vegetable oil about 10 t of biodiesel are obtained together with 1 ton of glycerol as co-product. Glycerol has an interesting energy content and can be used to provide heat and electricity to the same transesterification plant. Pyrolysis of raw glycerol on a rotary kiln reactor can present some difficulties in feeding it with a fluid product, for this reason, the glycerol was previously pelletized with sawdust to produce a solid fuel. Pellets with two concentrations of glycerol were studied: 20%w and 40%w. The results of the experimental campaign performed in the framework of the project TERVEG, partially funded by the Italian Ministry of Agriculture, Food and Forestry, are described in this paper. The results of pelletizing tests showed that the optimal percentage of glycerol is about 20%w, or lower. In fact, this pellet has good durability and good energetic performances, when pyrolysed. Pyrolysis tests performed at 600 °C showed that pellet with 40% glycerol has a reduced production of the liquid phase and a higher production of the gaseous phase. Nevertheless, the higher heating value of the gas obtained by pellet with 20%w glycerol and pellet with 40% glycerol is similar and it is about 14 MJ/kg

Stochastic power management approach for a hybrid solid oxide fuel cell/battery auxiliary power unit for heavy duty vehicle applications

The present paper aims to develop an innovative real-time power management strategy dedicated to the efficient operation of an auxiliary power unit (APU) in a heavy-duty vehicle. Specifically, the APU comprises a Solid Oxide Fuel Cell (SOFC) system and a Lead-Acid battery pack. The power management strategy envisages optimal power sharing between the APU elements and it is defined based on Simultaneous Perturbation Stochastic Approximation (SPSA) principle, pursuing SOFC power profile smoothing in real-time. The SPSA-based algorithm introduced here overcomes real-time operation issues remarked in other implementations (fuzzy logic, genetic algorithms), accounting for a robust and less complex formulation. The power management strategy is implemented in a dynamic model developed in Matlab/Simulink, simulating SOFC-based APU behavior. Simulation outcomes highlight that the proposed strategy allows a global energy saving over 6% if compared to a conventional power management, based on power split control. Moreover, comparing the power profiles corresponding to the battery and the SOFC, it is remarked as SOFC power oscillations evaluated over 1 s timeframe are halved, achieving values lower than 4.5 W/s for more than 80% of the operation time