Conciliare sicurezza alimentare e impatti ambientali: Water Footprint di scenari di produzione agricola nella Striscia di Gaza

Il presente studio analizza gli impatti ambientali e, in particolare, l’impronta idrica della produzione agricola su piccola scala nella Striscia di Gaza, area in cui le risorse naturali sono scarse, la densità demografica è molto elevata e buona parte della popolazione soffre di insicurezza alimentare. L’analisi confronta in una prospettiva di ciclo di vita una serie di scenari di rotazione colturale in termini di Water Footprint e di impatto ambientale, valutato mediante il metodo ReCiPe. I risultati mostrano discordanze tra gli ordinamenti dei diversi scenari ottenuti mediante le due metodologie. Viene, inoltre, valutata l’opportunità di affiancare alla produzione agricola l’acquacoltura basata sull’utilizzo dei bacini di accumulo dell’acqua piovana allo scopo di migliorare l’approvvigionamento proteico della popolazione. Risultati preliminari suggeriscono che tale attività non sia una soluzione efficiente in termini di consumi idrici, a causa degli elevati tassi di evaporazione

End-of-Life Impact on the Cradle-to-Grave LCA of Light-Duty Commercial Vehicles in Europe

A cradle-to-grave life cycle assessment focused on end-of-life (EoL) was conducted in this study for three configurations of a light-duty commercial vehicle (LDCV): diesel, compressed natural gas (CNG), and battery electric vehicle (BEV). The aim is to investigate the impact of recycling under two EoL scenarios with different allocation methods. The first is based on the traditional avoided burden method, while the second is based on the circular footprint formula (CFF) developed by the European Commission. For each configuration, a detailed multilevel waste management scheme was developed in compliance with the 2000/53/CE directive and ISO22628 standard. The results showed that the global warming potential (GWP) impact under the CFF method is significantly greater when compared to the avoided burden method because of the A-parameter, which allocates the burdens and benefits between the two connected product systems. Furthermore, in all configurations and scenarios, the benefits due to the avoided production of virgin materials compensate for the recycling burdens within GWP impact. The main drivers of GWP reduction are steel recycling for all of the considered LDCVs, platinum, palladium, and rhodium recycling for the diesel and CNG configurations, and Li-ion battery recycling for the BEV configuration. Finally, the EoL stage significantly reduces the environmental impact of those categories other than GWP

Preparation and characterization of graphene oxide based membranes as possible Gas Diffusion Layers for PEM fuel cells with enhanced surface homogeneity

The aim of this work is to define and optimize a process to produce a membrane made of reduced graphene oxide, r-GO, aiming to use it as Gas Diffusion Layer, GDL, in a Polymer Electrolyte Membrane Fuel Cell, PEMFC. Some works have reported that r-GO could reach conductivity values of about 104S/m; by using the "self-assembling" properties of GO, it would be possible to obtain a GDL with enhanced homogeneity, which maintains a good electronic conductivity. A reduction process of GO in aqueous solution was developed in order to get the desired conductivity value of the final product. The membrane was characterized through several techniques to assess key parameters and to understand its properties. In this work it was possible to obtain a membrane which has a maximum contact angle of 86° and a conductivity of about 421 S/m

Life Cycle Assessment of an NMC battery for application to electric light-duty commercial vehicles and comparison with a sodium-nickel-chloride battery

This paper presents the results of an environmental assessment of a Nickel-Manganese-Cobalt (NMC) Lithium-ion traction battery for Battery Electric Light-Duty Commercial Vehicles (BEV-LDCV) used for urban and regional freight haulage. A cradle-to-grave Life Cycle Inventory (LCI) of NMC111 is provided, operation and end-of-life stages are included, and insight is also given into a Life Cycle Assessment of different NMC chemistries. The environmental impacts of the manufacturing stages of the NMC111 battery are then compared with those of a Sodium-Nickel-Chloride (ZEBRA) battery. In the second part of the work, two electric-battery LDCVs (powered with NMC111 and ZEBRA batteries, respectively) and a diesel urban LDCV are analysed, considering a wide set of environmental impact categories. The results show that the NMC111 battery has the highest impacts from production in most of the impact categories. Active cathode material, Aluminium, Copper, and energy use for battery production are the main contributors to the environmental impact. However, when vehicle application is investigated, NMC111-BEV shows lower environmental impacts, in all the impact categories, than ZEBRA-BEV. This is mainly due to the greater efficiency of the NMC111 battery during vehicle operation. Finally, when comparing BEVs to a diesel LDCV, the electric powertrains show advantages over the diesel one as far as global warming, abiotic depletion potential-fossil fuels, photochemical oxidation, and ozone layer depletion are concerned. However, the diesel LDCV performs better in almost all the other investigated impact categories

Low-Cost PEM Fuel Cell Diagnosis Based on Power Converter Ripple With Hysteresis Control

This paper deals with a low-cost diagnostic technique for polymer electrolyte membrane (PEM) fuel cells (FCs), which exploits the ripple produced by power converters to monitor the equivalent ohmic resistance. While the available literature on this topic is focused on constant-frequency control of the power converter (such as pulsewidth modulation), this paper discusses the measurement issues that arise when hysteresis current control is employed for a dc/dc boost converter, which represents the simplest solution from the implementation point of view, and therefore particularly suitable for low-cost applications. The classic frequency-domain analysis for ohmic resistance identification, based on the Fourier transform, is compared with a time-domain analysis based on a simple identification algorithm, and a real-time implementation of the latter is presented. The experimental results are obtained on a single PEM FC, but the extension to FC stacks for commercial applications is also discussed

Microstructural Study of the Intermetallic Bonding Between Al Foam and Low Carbon Steel

Bonding between a metal foam core and a metallic skin is a pre requisite for the technological application of aluminum foam as filling reinforcement material to improve energy absorption and vibration damping of hollow components. This work is a preliminary study for the microstructural characterization of the interface layer formed between a commercial powder metallurgy (PM) precursor and a steel mould during foaming. The microstructure of the intermetallic layer was characterized by scanning electron microscopy, electron probe microanalysis and nanohardness measurements on the cross section. X-ray diffraction measurements, performed on the foam/substrate surface after stepwise material removal, allow the identification of the intermetallic phases. Two intermetallic layers, identified as Fe2Al5 and FeAl3, characterize the low Si foam/substrate while the AlSi10 foam/substrate interface evidences the presence of three Fe(Si, Al) intermetallic layers with different composition. Two and three different phases of increasing hardness could be distinguished going from the foam to the steel substrate for AlMg1Si0.6 and AlSi10 precursors respectively. The results suggest the importance of elemental diffusion from steel substrate in the molten aluminum matrix (foam). The possibility to control and tailor the microstructural properties of the interface between foam and steel skin is of fundamental importance in the technological process of foam filled structures manufacturing

PEM Fuel Cell Drying and Flooding Diagnosis With Signals Injected by a Power Converter

In this paper, a low-cost approach for polymer electrolyte membrane fuel cell (FC) drying and flooding diagnosis based on power converter ripple is presented, suitable to be implemented in commercial applications. If proper signal processing algorithms are employed, the high-frequency ripple inherently produced by switch-mode converters allows one to monitor the FC ohmic resistance, which is a good indicator for membrane drying, while an ad hoc switching control of the converter allows one to monitor also the low-frequency impedance, which is an indicator for cell flooding. This technique is tested with a dc/dc boost converter directly connected to a single cell, discussing how different FC operation modes (such as constant current or constant voltage) may affect the sensitivity required to the diagnostic algorithm to correctly recognize drying and flooding occurrences

Concrete with Organic Waste Materials as Aggregate Replacement

The disposal of high volumes of organic waste is a global issue. Using organic waste instead of sand as an aggregate material for concrete could reduce the strain on waste treatment processes and on the extraction of finite resources. At the same time, it could be a climate change mitigation strategy, by storing the biogenic carbon contained in the organic waste. This project investigated the viability of replacing 10% of fine aggregate in concrete with various organic waste materials, namely rice husk ash, wood ash, corncob granules, and wheat straw. The fresh concrete’s properties were studied using the slump test, and the hardened concrete’s mechanical properties were measured using the compressive strength and flexural strength tests. In this study, 14 days of curing were considered for the mechanical tests, although the 28-day mechanical strength is more generally accepted. The mechanical performances along with a life cycle assessment (LCA) comparison between the concrete with organic waste and traditional concrete were conducted. The results suggested that rice husk ash and wood ash are the most-suitable organic waste products for use as aggregate replacers considering the mechanical properties. The concrete samples incorporating wheat straw and corncob granules exhibited relatively low strength; unless advanced treatment methods are applied to enhance the concrete’s performance, the utilization of these organic wastes in concrete may be limited. The environmental impact assessment of traditional concrete shows that the main contributor to almost every impact category is the production of Portland cement. Sand production contributes only marginally to the overall impact of the concrete. In terms of life-cycle greenhouse gas (GHG) emissions, traditional concrete exhibits the lowest GWP impact per cubic meter when mechanical properties are included in the functional unit used for the comparison. Nevertheless, concrete samples with wood ash and rice husk ash partially offset their lower compressive strength with higher carbon sequestration, showing a similar GWP impact to traditional concrete. This makes them promising alternatives, especially for cases where limited compressive strengths are needed. Further investigations to improve their mechanical properties and optimize their performance are warranted