137262 research outputs found
Sort by
Componente della Commissione Scientifica preposta all’Edizione Nazionale delle opere di Costantino Mortati, istituita con Decreto del Ministro della Cultura del 27/2/2024, n. 75, e Segretario della medesima Edizione (v. nota MIC DG Eric_Serv IIII02/05/2024I0019463-P).
No full text
Linear Matrix Inequality‐based design of distributed proportional‐integral‐derivative for the output consensus tracking in heterogeneous high‐order multi‐agent systems
No full textThis article addresses the cooperative output consensus tracking problem for high-order heterogeneous multi-agent systems via a distributed proportional-integral-derivative (PID)-like control strategy and proposes two novel control methodologies for the tuning of the control gains, which do not require any assumption and/or limitation on agent system modeling. By extending the static output feedback (SOF) paradigm to distributed domain, the asymptotic stability problem for the overall MAS composed of (Formula presented.) agents is revisited into (Formula presented.) decoupled stabilization problems to be solved. Then, by exploiting the Lyapunov and matrix theory, the typical SOF bilinear matrix inequality (BMI)-based stability conditions are recast into (Formula presented.) feasible linear matrix inequality (LMI)-based ones, whose solutions allow finding the proper values of the PID control gains ensuring the achievement of the cooperative task. In doing so, the proposed procedures reduce the computational effort required for the control design, hence providing a greater attraction for a wider range of practical engineering applications. The scalability and the adaptability of the proposed control methodology in solving an alternative cooperative control problem in the presence of multiple leaders, that is, the output containment task, are also analytically investigated. Numerical simulations confirm the effectiveness of the theoretical derivations
Improvement of Functional and Technological Properties of Chickpea Aquafaba Through Lactic Fermentation
No full textBioconversion processes represent sustainable, environmentally friendly, and cost-effective tools to improve the nutritional quality, bioactivity, and technological properties of agri-food waste. The chickpea cooking wastewater aquafaba, commonly used as an egg-replacer ingredient in various food formulations, was investigated as a suitable substrate for Lacticaseibacillus paracasei NPB-01's growth, which reached a final bacterial load of 9 Log and lactic acid production of 2.16 g/L after 24 h of process. Despite total saponins and polyphenols showing nonsignificant differences before and after fermentation, a significant improvement in the antioxidant power of fermented aquafaba was found. The microbial proteolysis and the simultaneous approach of pH to the chickpea proteins' isoelectric value (approximately 4.5) conferred high surface hydrophobicity and flexibility to the protein units, emphasizing the technological characteristics of aquafaba. In particular, a tenfold-enhanced emulsifying capacity and a significant improvement in foam and emulsion stability (98% and 100%, respectively) were observed, confirming the potential of fermented aquafaba as an enhanced texture-modifying ingredient with probiotic and antioxidant properties
Hydrogen production by the water-gas shift reaction: A comprehensive review on catalysts, kinetics, and reaction mechanism
No full textThe global push towards a hydrogen economy fuels hydrogen production from various sources. A crucial step in enriching hydrogen and reducing CO in syngas derived from carbon-based hydrogen production is the water-gas shift reaction (WGSR). Given the equilibrium-limited nature of WGSR, low temperatures are necessary to reduce carbon monoxide concentrations to the desired level. Traditionally, iron‐chromium (Fe/Cr) and copper‐zinc (Cu/Zn) catalysts have been widely used at high and low temperatures, respectively. Numerous studies have focused on developing optimal WGS catalysts with the desired characteristics and efficiency. This review extensively discusses various catalysts for different stages of WGSR, including low, medium, high-temperature, and sour WGS catalysts. However, understanding the contrast between the redox and associative mechanisms and the nature of intermediates in the WGS pathway remains unclear. A detailed study of the WGSR pathway is imperative to develop highly active and stable catalysts. Various experimental kinetic values and models have also been reported to elucidate the WGSR mechanism at different temperatures. The primary deactivation sources of WGS catalysts have been discussed to highlight recent advances to improve catalyst performance. The contribution of computational methods such as Density Functional Theory (DFT) to developing WGS catalysts is also explored. Furthermore, the review addresses the challenges encountered in the WGSR, and recommendations and conclusions are drawn to guide future research efforts
Hydrodefluorination with Heterogeneous Ziegler-Natta Catalysts
No full textThis project aims to develop a hydrodefluorination (HDF) method exploiting immobilized TiIII-H species on heterogeneous Ziegler-Natta (ZN)
catalysts, employing high-throughput experimentation (HTE) and solid-state analysis techniques. Studies on the model substrate
perfluoropyridine (PFPy) highlight the ability of ZN systems to engage in HDF. H2 gas is used as a promoter in the reaction to speed up the regeneration of the active species. Activity and selectivity can be influenced by the makeup of catalytic formulation. Turnover numbers (TONs) in the order of >10E4 can be inferred under the assumption that only 1% of the Ti particles on the catalyst are active. ZN systems are cheap, tunable and a wealth of information from 70 years of research can be exploited. Selective HDF of per- and polyfluorinated substrates could yield novel building blocks for e.g. the pharmaceutical industr
A Benchmark Between Conventional and Custom Heat Treaments for Inconel 718 Alloy Processed Through Cold Metal Transfer Technology
No full textInconel 718, one of the most employed nickel-based superalloys, proved to be efficiently processable through Wire-Arc Additive Manufacturing (WAAM), including Cold Metal Transfer Technology (CMT). Nevertheless, a multi-step heat treatment is still necessary to control the microstructure and the mechanical properties of this complex alloy. This work aimed to compare the effects on microstructure, tensile properties, Vickers microhardness and chemical composition of two heat treatments performed on Inconel 718 parts produced through CMT, namely: i) the heat treatment used for conventionally processed Inconel 718 parts, defined by the AMS5662 and AMS5663 standards; ii) a custom heat treatment that reduces the number of steps included in the previous case. The experiments were performed on prismatic CMT-produced parts, subsequently machined to extract the test specimens, considering both the aforementioned heat treatment conditions as well as the as-deposited material. The results suggested that comparable results were achieved for the selected heat treatments, however, a complete recrystallization of the fine grains never occurred for all the investigated conditions, thus retaining the typical microstructural anisotropy deriving from the CMT process. Moreover, the heat-treated parts showed, in any case, comparable properties to those of the conventionally cast alloy, opening a new scenario in the context of industrial production of semi-finished parts with huge costs and time savings
Evaluation of the Multi-Year-on-Year method for degradation analysis in photovoltaic systems
No full textEnhancing Biomedicine: Proteomics and Metabolomics in Action
No full text: The rapid and substantial advancements in proteomic and metabolomic technologies have revolutionized our ability to investigate biological systems [...]
Sea Grape (Caulerpa racemosa) Kombucha: A Comprehensive Study of Metagenomic and Metabolomic Profiling, Its Molecular Mechanism of Action as an Antioxidative Agent, and the Impact of Fermentation Time
No full textSea grape kombucha has been known to exhibit high antioxidant activity due to its ele-vated total polyphenol content. This study aims to identify and characterize the active microbial community involved in the fermentation of kombucha using sea grapes (C. rac-emosa) as the primary substrate. Furthermore, it evaluates the effects of different Symbi-otic Culture of Bacteria and Yeast (SCOBY) starter concentrations on the physicochemical properties and antioxidant activity of sea grape kombucha. Our results showed that the pH of the kombucha was higher after 7 days of fermentation compared to later time points. The microbial community was composed of 97.08% bacteria and 2.92% eukaryotes, divided into 10 phyla and 69 genera. The dominant genus in all samples was Komaga-taeibacter. Functional profiling based on 16S rRNA data revealed that metabolic functions accounted for 77.04% of predicted microbial activities during fermentation. The most en-riched functional categories were carbohydrate metabolism (15.70%), cofactor and vita-min metabolism (15.54%), and amino acid metabolism (14.24%). At KEGG Level 3, amino acid-associated pathways, particularly alanine, aspartate, and glutamate metabolism (4.24%), were predominant. The fermentation process in sea grape kombucha is primarily driven by carbohydrate and amino acid metabolism, supported by energy-generating and cofactor biosynthesis pathways. Our findings indicate that different metabolic pathways lead to variations in kombucha components, and distinct fermentation stages result indifferent metabolic reactions. For instance, early fermentation stages (Day 7) are dominated by amino acid metabolism, whereas the late stages (Day 21) show increased activity
in carbohydrate and sulfur metabolism. Metabolomic analysis revealed that increasing the
SCOBY starter concentration significantly influenced pH, soluble solid content, vitamin
C, tannin, and flavonoid content. These variations suggest that fermentation duration and
microbial composition significantly influence the spectrum of bioactive metabolites,
which synergistically provide functional benefits such as antimicrobial, antioxidant, and
metabolic health-promoting activities. For example, sample K1 produced more fatty acids
and simple sugar alcohols, sample K2 enriched complex lipid compounds and phytosterols,
while sample K3 dominated the production of polyols and terpenoid compounds