Total cost of ownership of electric vehicles using energy from a renewable-based microgrid

This work aims at analyzing the integration between electric mobility and renewable energy sources studying the case of the grid-connected microgrid under construction at the University of Trieste, Italy. A general model able to estimate the charging price and the resulting total cost of ownership per kilometer considering the match between the demand and the production of a photovoltaic generator is presented. The result is that the electric vehicle is mainly charged with the produced renewable energy (72%) and that the 60% of it flows through the storage unit. The study also presents a sensitivity analysis to show how the battery size and cost, together with the travelled distance, influence the charging price and the total cost of ownership per kilometer. Considering the current Italian prices and subsidies, results show that the use of an electric car is today feasibl

Engineering of colloidal nanocrystal thin films and their optoelectronic properties: A simple and effective route

This work investigates the effect of heat treatments on CdSe/CdS core\u2013shell nanocrystals assemblies with different sizes and capping ligands. Nanostructured thin films, consisting of an array of CdSe quantum dots embedded in a continuous matrix of CdS, have been obtained by mild thermal treatments of CdSe/CdS core\u2013shell nanocrystals deposited on glass substrates from colloidal solution. These materials are regarded as promising photon upconverters, or absorbers for high-efficiency photovoltaic devices. The treatments were conducted in the range 300\u2013550 \ub0C for up to 150 min. The nanoscale evolution during the heat treatment was investigated by monitoring optical properties of the films. Initially, the well-defined photoluminescence band, corresponding to the first quantum dots exciton state, rapidly shifts towards lower energy, indicating delocalization of the exciton and suggesting that nanocrystal CdS shells are merging by sintering mechanisms, thus forming a continuous matrix. Control over this phase of the heat treatment leads to the desired nanoscale morphology and properties. The kinetics of sintering has been characterized, and the procedure has been systemically applied to CdSe/CdS nanocrystals of different sizes and ligand types. This research provides novel values for the activation energy of the sintering process and strongly support the general applicability of such process to control and optimize optoelectronic properties of nanostructured thin films for applications like light-emitting diodes, tunable emitters and photoconductors among others

Development of n-DoF Preloaded structures for impact mitigation in cobots

A core issue in collaborative robotics is that of impact mitigation, especially when collisions happen with operators. Passively compliant structures can be used as the frame of the cobot, although, usually, they are implemented by means of a single-degree-offreedom (DoF). However, n-DoF preloaded structures offer a number of advantages in terms of flexibility in designing their behavior. In this work, we propose a comprehensive framework for classifying n-DoF preloaded structures, including one-, two-, and threedimensional arrays. Furthermore, we investigate the implications of the peculiar behavior of these structures-which present sharp stiff-to-compliant transitions at designdetermined load thresholds-on impact mitigation. To this regard, an analytical n-DoF dynamic model was developed and numerically implemented. A prototype of a 10DoF structure was tested under static and impact loads, showing a very good agreement with the model. Future developments will see the application of n-DoF preloaded structures to impact-mitigation on cobots and in the field of mobile robots, as well as to the field of novel architected materials

Mapping land use impact of photovoltaic farms via crowdsourcing in the Province of Lecce (Southeastern Italy)

Photovoltaics (PV) is the fastest-growing renewable energy source at the global level and Italy has been one of the pioneers of such growth, now being one of the Countries with the largest installed PV capacity \u2013 absolute, per unit area, and per capita. In this paper we investigated the impact of PV on land use in the area with the highest density of PV farms in Italy, i.e. the Province of Lecce (Southeastern Italy): here, such impact is expected to be maximum and has been the subject of public debate. In order to map all PV farms in detail, we used participative cartography, specifically OpenStreetMap (OSM), as data source. This international project collects geographic information (often gathered by people \u2013 i.e. the so-called Volunteered Geographic Information, VGI \u2013 using widely available technologies, such as smartphone built-in GPS), in order to create freely available global topographic maps. In this paper, we used the OSM platform to create a Geographical Information System (GIS) of PV farms in the Province of Lecce. Using GIS-based techniques, we estimated land use at the municipality level and created a density map of PV farms within the study area. Using the official land cover map Corine Land Cover of 2012, we also evaluated the main changes in land use. The results highlight the correlation between spatial distribution of PV farms and geographic variables (geomorphology, demographics, tourism, etc). We also show that land take by PV farms is quite marginal even in a region such as the Province of Lecce, where the density of PV installed power is among the highest available at the global level

Recycling alginate composites for thermal insulation

We present a new method for the total functional recycling of alginate-based composite materials made via ionotropic gelation. The original material, an alginate/fiberglass foam with thermal insulation characteristics, was produced following a patented process in which fiberglass waste is embedded into the polyanionic gel matrix, and the resulting compound is then freeze-dried. The functional recycling is carried out by disassembling the ionic matrix \u2013 which is initially formed by the interaction between a cation (e.g. calcium) and the negatively charged alginate backbone \u2013 with the use of a chelator (Ethylenediaminetetraacetic acid disodium salt) with a high affinity for the cations, thus obtaining a homogeneous solution. An ionotropic gel can then be re-formed upon deactivation of the chelating activity under mild acid conditions. We managed to maintain or improve the thermal, mechanical and acoustic performances of the original material and we successfully tested the possibility of multiple recycling cycles

The effect of manufacturing mismatch on energy production for large-scale photovoltaic plants

In the literature, the effect of the mismatch due to manufacturing tolerances on PV plant productivity has been investigated under the hypothesis of plant operation in Standard Test Conditions (STC). In this paper, mismatch impacts are evaluated in more realistic terms taking into account various possible operating conditions. Results are illustrated through the study case of a 1 MWp solar park for which module datasheets as well as flash test data are available. The plant production is evaluated assuming operating conditions that comply with the European efficiency standards. It is shown how the effect of a given mismatch on the annual productivity estimation can significantly change depending on the operating conditions

Polished stone axes from Varna/Nössingbühel and Castelrotto/Grondlboden, South Tyrol (Italy)

A collection of polished stone axes from a late Neolithic site and an Early Bronze Age hill fort in South Tyrol (Italy) have been analysed through a multi-analytical approach, mainly based on non-destructive techniques (i.e. Raman spectroscopy, X-ray fluorescence and prompt gamma activation analysis) to identify the raw materials used in the same area during different periods and compare them with those in use in the surrounding territories. The analytical results suggest raw material exploitation strategies based on local or close sedimentary, metamorphic and magmatic rocks. Most of the artefacts are made from antigoritic serpentinite, whose origin is probably from Hohe Tauern (Austria) or related secondary deposits. These data confirm the importance of such raw material for the production of polished stone axes during recent prehistory and integrate the present knowledge about the distribution of antigoritic artefacts in north-eastern Italy and neighbouring countries

Energy Scheduling and Performance Evaluation of an e-Vehicle Charging Station

This paper proposes an energy management system (EMS) for a photovoltaic (PV) grid-connected charging station with a battery energy storage system (BESS). The main objective of this EMS is to manage the energy delivered to the electric vehicle (EV), considering the price and (Formula presented.) emissions due to the grid’s connection. Thus, we present a multi-objective two-stage optimization to reduce the impact of the charging station on the environment, as well as the costs. The first stage of the optimization provides an energy schedule, taking into account the PV forecast, the hourly grid’s (Formula presented.) emissions factor, the electricity price, and the initial state of charge of the BESS. The output from this first stage corresponds to the maximum power permitted to be delivered to the EV by the grid. Then, the second stage of the optimization is based on model predictive control that looks to manage the energy flow from the grid, the PV, and the BESS. The proposed EMS is validated using an actual PV/BESS charging station located at the University of Trieste, Italy. Then, this paper presents an analysis of the performance of the charging station under the new EMS considering three main aspects, economic, environmental, and energy, for one month of data. The results show that due to the proposed optimization, the new energy profile guarantees a reduction of 32% in emissions and 29% in energy costs

BRDF characterization of Al-coated thermoplastic polymer surfaces

In this paper, we present a combined morphological and optical characterization of aluminum-coated thermoplastic polymer surfaces. Flat plastic substrates, obtained by means of an injection molding process starting from plastic granules, were coated with ultra-thin aluminum films evaporated in vacuo, on top of which a silicon-based protective layer was plasma deposited in order to prevent oxidation of the metal reflective surface. Different sample treatments were studied to unravel the influence of substrate chemistry, substrate thickness, aluminum and protective layer thickness, and surface roughness on the actual optical reflectance properties. Bidirectional reflectance distribution function measurements, corroborated by surface morphological information obtained by means of atomic force microscopy, correlate reflectance characteristics with the root-mean-square surface roughness, providing evidence for\ua0the role of the substrate and the thin films\u2019 morphology. The results unravel information of interest within many applicative fields involving metal coating processes of plastic substrates as an example in the case of automotive lighting

Trace Elements in Chromian Spinels from Four Siberian Kimberlites

We analysed the major, minor and trace elements chemistry of forty-two Cr-spinels from four Siberian kimberlites. They showed a wide range in Mg# (Mg/(Mg + Fe2+); 0.42–0.78) and Cr# (Cr/(Cr + Al); 0.32–0.92) and a common trend of increasing Cr# with decreasing Mg#. The major element classification schemes suggested that there were spinels deriving from a peridotitic source (Xen) and spinels crystallised from kimberlitic melts (Chr). Laser-Ablation Inductively Coupled Plasma Mass Spectrometry on both groups showed that the trace elements with the highest abundance were Mn (985–3390 ppm), Ni (531–3162 ppm), V (694–2510 ppm) and Zn (475–2230 ppm). Testing the effectiveness of trace elements in determining the source for Cr-spinels, we found out that Cr-spinels crystallised directly from a kimberlitic melt usually showed higher Mn, Ni, Sc and V concentrations with respect to those of peridotitic origin. In addition, using the available partitioning models, we found that the correlations between major elements and Ni, Co, Sc and Ga in the Xen group could be explained by subsolidus equilibration between spinel, olivine and clinopyroxene at 800–1000 °C, thus supporting a peridotitic source for this group. Finally, we calculated the composition of the possible melts in equilibrium with the Cr-spinels of the Chr group, using a selected set of partition coefficients. Calculated abundances of Cu, Ga and Zr were comparable to those of the kimberlite, while V was never close to the kimberlite composition. This simulation highlighted the need for new data on the trace elements partition coefficients between kimberlitic melts and Cr-spinel