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Pyrolysis of municipal sewage sludge: challenges, opportunities and new valorization routes for biochar, bio-oil, and pyrolysis gas
No full textThe efficient management of municipal sewage sludge (MSS) daily produced worldwide by biological wastewater treatment processes is nowadays of utmost importance. Classic treatment/disposal methods are affected by efficiency and/or safety issues. Innovative thermochemical treatments are gaining momentum as promising alternatives. Pyrolysis of MSS can result in the recovery of precious resources, such as nutrients and organic matter, and their conversion into three valuable fractions, i.e. biochar, bio-oil, and pyrolysis gas. These products are employable in innovative biorefinery pathways towards a wide range of value-added materials. In this review, an integrated biorefinery platform for MSS valorization is presented. After a brief introduction on MSS properties and issues related to its management, a deep focus on the influence that the feedstock and pyrolysis conditions have on the product yields and composition was conducted. Innovative valorization routes for biochar, bio-oil and pyrolysis gas were extensively discussed by highlighting challenges, opportunities, advantages and drawbacks. The characteristics required by these products to be efficiently valorized, as well as the main solution for their enhancement, were described. Additionally, economic considerations on MSS pyrolysis derived from full-scale applications conducted at the European and global level were elaborated. Finally, future perspectives about biochar, bio-oil and pyrolysis gas employment in cutting-edge upcycling routes have been reported
Nuclear safety Enhanced: A Deep dive into current and future RAVEN applications
Get PDFAs the horizon of nuclear energy expands with the advent of small modular reactors, Generation IV reactors, and fusion reactors, there is a growing perspective that the licensing process could benefit from a more comprehensive approach. Moving beyond traditional deterministic and probabilistic risk assessment analyses might pave the way for a novel safety analysis paradigm propelled by the increasing computational power at our disposal. This paper explores different methodologies that can improve the outcomes of nuclear safety analysis. These range from uncertainty quantification techniques, aimed at enhancing the precision of safety margins, to deploying dynamic event trees by driving system code simulations, capturing the potential evolutions of severe accidents. These methodologies offer a better understanding of the management and consequences of nuclear accident scenarios, significantly improving the accuracy and efficiency of safety predictions compared to traditional methods. Specific case studies illustrate the practical application of these advanced techniques, demonstrating substantial improvements in predicting and managing the dynamics of severe accidents. These findings underscore the effectiveness of these methodologies in enhancing risk assessment capabilities and informing decision-making processes for nuclear safety management. The paper also emphasizes the importance of adaptability and continuous evolution, a call for action to address emerging nuclear safety concerns and highlights the utility of advanced tools like RAVEN
Experimental insights on iron-based alloys corrosion in water cooled loops
Get PDFThis paper presents experimental findings on the behavior of iron-based alloys in environmental conditions typical of nuclear fusion technology, specifically focusing on material degradation, which is a critical aspect for the water cooling system of EU DEMO breeding blankets. The experimental campaign investigates potassium hydroxide's role as an alkalizing agent, testing various concentrations to assess its impact on corrosion resistance. Additionally, it examines how oxygen levels affect localized corrosion development, which is crucial for mitigating corrosion risks in fusion applications. Seven 1000-hour tests were conducted to determine optimal conditions for corrosion reduction. Findings include identifying an oxygen concentration threshold to prevent piping cracking on EUROFER97 specimens
Mortality from extreme meteorological and hydrogeological events in Italy: a rising health threat connected to climate change. Safety in Extreme Environments
No full textThe aim of the present work is to assess mortality associated to extreme meteorological and hydrological events (storms, floods, landslides, avalanches) for the period 2003–2020 in Italy. These extreme events are particularly worrying phenomena due to their increasing frequency and intensity connected to climate change. The considerable rise of extreme meteorological events in Italy has been having a dramatic impact on the environment and territories, particularly on intrinsically fragile ones, and on resident populations. More than 90% of Italian municipalities are at risk for extreme events, with more than 8 million inhabitants exposed. Number of deaths and SMRates due to such extreme events (X International Classification of Diseases: X36, X37 and X38) in Italy were calculated from regional to municipal level by ENEA mortality database (data source ISTAT). Geographic maps were elaborated by QGIS software (QGIS, RRID:SCR_018507) version 3.28. In the selected period, 378 overall deaths were detected: 321 deaths due to landslides and avalanches, 28 to cataclysmic storm, and 29 to floods. The regions with the highest mortality levels and/or number of municipalities involved and the municipalities at highest risk were identified. In consideration of the forecasted increase of such extreme events in Italy, the knowledge of Italian areas at highest risk can be used in the decision-making processes to assess priorities, allocate financial resources, define warning measures, and undertake preventive or mitigation actions. Moreover, the attributable mortality levels can be a useful basis for further risk assessment research aimed at estimating the cost in terms of human lives’ loss associated to such events in future climatic scenarios
Improved Compatibility of α-NaMnO2 Cathodes at the Interface with Ionic Liquid Electrolytes
No full textThe behaviour and compatibility of monoclinic sodium manganite, α-NaMnO2, cathodes at the interface with electrolytes based on the 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI) and N-trimethyl-N-butylammonium bis(fluorosulfonyl)imide (N1114FSI) ionic liquids is presented and discussed. The Na+ insertion process was analysed through cyclic voltammetry tests combined with impedance spectroscopy measurements and the cell performance was tested by charge-discharge cycles. XPS and FIB-SEM measurements allowed analysis of the surface composition and the morphology of post-mortem cathodes. Overall, the α-NaMnO2 cathode showed high reversibility in N1114FSI-based electrolyte, delivering 60 % of the initial capacity after 1200 cycles in conjunction with a Coulombic efficiency above 99 %. To our knowledge, these very promising results are the best result obtained till now for monolithic α-NaMnO2 cathodes, are ascribable to the formation of a stable passive layer onto the electrode surface, as confirmed by spectroscopic analysis
n-Dimensional non-commutative GUP quantization and application to the Bianchi I model
Get PDFWe analyse a n-dimensional Generalized Uncertainty Principle (GUP) quantization framework, characterized by a non-commutative nature of the configurational variables. First, we identify a set of states which are maximally localized only along a single direction, at the expense of being less localized in all the other ones. Subsequently, in order to recover information about localization on the whole configuration space, we use the only state of the theory which exhibits maximal localization simultaneously in every direction to construct a satisfactory quasi-position representation, by virtue of a suitable translational operator. The resultant quantum framework is then applied to model the dynamics of the Bianchi I cosmology. The corresponding Wheeler–DeWitt equation is reduced to Schrödinger dynamics for the two anisotropy degrees of freedom, using a WKB representation for the volume-like variable of the Universe, in accordance with the Vilenkin scenario. The main result of our cosmological implementation of the constructed quantum theory demonstrates how the dynamics of a wave packet peaked at some point in the configuration space represented in the quasi-position variables favours as the most probable configuration exactly the initial one for a relatively long time, if compared with the ordinary quantum theory. This preference arises from the different dynamical behavior exhibited by wave packets in the two quantum theories
Inhibitors derived from wheat straw hydrolysate can affect the production of succinic acid by Actinobacillus succinogenes
Get PDFLignocellulosic biomasses are promising source of fermentative sugars for the production of succinic acid. The lignocellulosic matrix must be pretreated to make the sugars available for the fermentation, but the most tested operative conditions can generate inhibitors as acetic acid, furans, phenolic compounds. Inhibitors remained an obstacle for the implementation of succinic acid production starting from recalcitrant biomasses as wheat straw. Batch tests were performed at two starting concentrations of strain, sugars (glucose, glucose and xylose) and inhibitors (acetic acid and furfural) by comparing the fermentation in standard broth medium and hydrolysate. Notwithstanding the presence of acetic acid (52.5 mg/L) and furfural (15 mg/L), succinic acid was obtained at 9*10−2 ± 7*10−3 g/L by starting from wheat straw hydrolysate that contained glucose (1.1 g/L), xylose (0.4 g/L) and without additional nitrogen source. Therefore, the study highlighted that a more concentrated inoculum was able to reduce the synergistic effect of inhibitors at their highest concentrations. The results obtained may contribute to improve succinic acid production from the biomasses that have been under-exploited but abundantly available, as wheat straw, for which solutions must be found to solve the problem of inhibitors production or to mitigate its effect on the fermentation process
Investigative photometry experiments on planar extended-light sources
Get PDFThe inverse-square decay law of the illuminance of a point light source with distance is a common notion of basic optics theory, which is readily demonstrated to be a direct consequence of the propagation of spherical wave fronts with the centre at the light source. It is far less common to address the experimental verification of this law and, even less, to study the illuminance decay with the distance of extended light sources, which somehow represent an unknown topic. We propose a scientific experiment where the light sensor of a smartphone is used to collect illuminance data as a function of the source-to-sensor distance and orientation. Through this procedure, students can realize the limit of validity of the inverse-square law and determine the luminance flux of the chosen point-like light source (e.g. the white LED flashlight of a smartphone). More interestingly, when dealing with extended sources (e.g. the LCD of a laptop displaying a white image) subtle characteristics of the decay trend emerge, particularly for distances lower that the source size. A detailed analysis of these characteristics is presented though a process allowing student engagement in a real scientific investigation, envisaging steps of data acquisition through experimental measurements, model construction on the basis of the observed patterns, and finally model testing. We provide a guided formulation for the general modelling of planar emitters, starting from the theoretical treatment of Lambertian sources. In this way, students are able to quantify the luminous emission also for extended sources and their deviation from a Lambertian behaviour
Electromagnetic Analysis of the Demo Magnet System: Electrical Behavior of a Toroidal Field Coil During an Electrical Transient
No full textThe toroidal magnet system of DEMO includes 16 toroidal field coils (TFCs) for vacuum vessel plasma confinement. Because all the coils are superconductive, during their operation, they could experience an unexpected quench (changing from a superconducting to a normal conducting state). Once the quench signals are validated, the quench protection system is activated to dump the magnetic energy into an external resistor to prevent potential damage. However, the electrical transient in the magnet system can lead to overvoltage or overcurrent across and inside each coil. To select the insulation coordination and the test voltage of the coils, the assessment of this electromagnetic load is necessary. Based on the international thermonuclear experimental reactor (ITER)-like topology and considering the winding pack geometry associated with the baseline scenario and the high-current scenario, a preliminary electromagnetic analysis is performed by the finite element method (FEM) model: the target is the knowledge of the inductance matrix of the TFC system in both the scenarios. Starting from this result, lumped networks have been implemented and used to investigate the transient behavior of the TFC system. In particular, the distribution of the voltage waveform, across and among adjacent layers of each TFC, during a fast discharge, has been estimated for different operative conditions: fast discharge unit synchronous and asynchronous activation. The simultaneous occurrence of a fault condition during the discharge has also been considered
Solanum pennellii (LA5240) backcross inbred lines (BILs) for high resolution mapping in tomato
Get PDFWild species are an invaluable source of new traits for crop improvement. Over the years, the tomato community bred cultivated lines that carry introgressions from different species of the tomato tribe to facilitate trait discovery and mapping. The next phase in such projects is to find the genes that drive the identified phenotypes. This can be achieved by genotyping a few thousand individuals resulting in fine mapping that can potentially identify the causative gene. To couple trait discovery and fine mapping, we are presenting large, recombination-rich, Backcross Inbred Line (BIL) populations involving an unexplored accession of the wild, green-fruited species Solanum pennellii (LA5240; the ‘Lost’ Accession) with two modern tomato inbreds: LEA, determinate, and TOP, indeterminate. The LEA and TOP BILs are in BC2F6–8 generation and include 1400 and 500 lines, respectively. The BILs were genotyped with 5000 SPET markers, showing that in the euchromatic regions there was one recombinant every 17–18 Kb while in the heterochromatin a recombinant every 600–700 Kb (TOP and LEA respectively). To gain perspective on the topography of recombination we compared five independent members of the Self-pruning gene family with their respective neighboring genes; based on PCR markers, in all cases we found recombinants. Further mapping analysis of two known morphological mutations that segregated in the BILs (self-pruning and hairless) showed that the maximal delimited intervals were 73 Kb and 210 Kb, respectively, and included the known causative genes. The ‘Lost’_BILs provide a solid framework to study traits derived from a drought-tolerant wild tomato