A feasible feedstock for waste-to-energy applications is refuse-derived fuel (RDF), a diverse blend composed of plastic and waste from biomass. Nevertheless, there is still a lack of quantification regarding the combined impacts of short vapor residence durations and feedstock composition in fluidized-bed decompositions. In order to close this gap, this study compares two compositionally different RDFs in a standard laboratory-sized fluidized-bed reactor under fast thermal pyrolysis conditions (550-600 degrees C, 2-5 s). At 550 degrees C, plastic-rich RDF 1 yielded a maximum liquid yield of 58 wt%, which was made up of hydrocarbon-rich oil with a high thermal value (HHV(dry) = 37.8 MJ kg(-1)) and a significant aromatic content. On the other hand, biomass-rich RDF 2 produced 52 wt%, liquid at 570 degrees C, with somewhat lower HHVs (35.9-39.2 MJ kg(-1)) and a higher oxygen and water concentration. Detailed characterization of the feedstock, resulting bio-oils, gases, and chars was conducted using TGA, FT-IR, NMR, GC-MS, SEM, and XRD techniques to elucidate the influence of temperature, residence time, and feedstock composition on product yield and quality. For biomass-rich RDF 2, raising the temperature from 570 degrees C to 600 degrees C decreased liquid yield while boosting olefinic entities, gaseous hydrocarbons, and suggesting increased secondary fracturing processes. Hydrocarbon, phenolic substances, and oxygenate distributions are highly dependent on RDF composition, according to product composition studies, with biomass-rich RDF tends to produce more oxygenated compounds while plastic-rich RDF tends to produce more aromatic compounds. These findings show that while minor temperature spikes (30 degrees C) can reroute products from liquids to gases, feedstock composition can shift liquid yield by up to similar to 6 wt% and considerably impact fuel performance. In order to optimize RDF valorization in fluidized-bed systems, this work offers quantitative data that links RDF composition and fast pyrolysis parameters to product distribution.
The purpose of this study is to evaluate the feasibility and operational efficiency of retrofitting a Cessna 208B aircraft with a hydrogen-electric propulsion system for short-haul cargo operations. Unlike conventional studies relying on idealized flight profiles, this research leverages real-world Automatic Dependent Surveillance-- Broadcast (ADS-B) data sourced from Flightradar24 to simulate five actual flight missions. The methodology involved reconstructing second-by-second mission profiles through interpolation of non-uniform ADS-B time series, followed by high-resolution simulation of energy consumption and hydrogen fuel usage using a custom Python-based propulsion model. Key system components, including a proton-exchange membrane fuel cell, motor, inverter and mechanical transmission, were modeled using fixed efficiencies. The system excludes battery buffering, allowing for direct analysis of hydrogen fuel demand across all flight phases, including taxi, takeoff, climb, cruise, descent, and post-landing operations. The results demonstrate that total hydrogen consumption per mission ranged between 17.15 kg and 25.28 kg, well below the onboard storage capacity of 70 kg. Importantly, taxi phases accounted for up to 10% of total hydrogen use, highlighting an often neglected but significant contributor to overall energy demand. Comparative analysis across missions revealed that descent profile, cruise altitude and ground operation duration strongly influence energy efficiency. In conclusion, the study confirms the technical viability of hydrogen retrofits for regional cargo aircraft, offering low fuel consumption and mission-level feasibility. The findings also reinforce the value of integrating ground phases and real trajectory data in future hydrogen-electric aircraft performance evaluations.
This work investigates the effect of electroadhesion on the smooth soft contact mechanics between a silicone rubber ball and a glass slide, both functionalized to be electroactive and biocompatible. In particular, the influence of electroadhesion on the pull-off force, real contact area, and friction force is experimentally studied using a lab-made tribometer both in dry and wet contact conditions. The role of the applied voltage frequency, interface dielectric properties and crack viscoelasticity is also theoretically disclosed. The results show that the interface electric potential can be designed to precisely control the contact mechanics, including friction and adhesion, thanks to the additional Maxwell stresses applied to the contact, either in dry and lubricated conditions. This is of particular interest for tribotronics, soft robotics and biointerface technologies.
We collect several results related to the Symmetrized Fractional Variation model for signal and image denoising (shortly denoted SFV): a variational approach based on L1 fitting data term together with regularizing terms exploiting a distributional version of Riemann-Liouville fractional derivatives. We enhance the analysis of the one-dimensional case through the study of the space BV*s of admissible signals on a bounded interval, say the functions with bounded variation of both sides fractional derivatives for a prescribed real positive order s. We show that the embedding in BV*s of the Sobolev space of the same fractional order is strict. We exhibit some nontrivial borderline examples of admissible or non admissible functions in the space BV*s. We prove several relationships between related fractional calculus and the integral transforms. The SFV model is discretized based on a second-order consistent Grunwald Letnikov scheme and coupled with an automatic selection procedure of all model parameters relying on the whiteness principle: some numerical simulations are presented to show the efficacy of the proposed approach in denoising one-dimensional signals corrupted by impulsive noise modelled by the Laplace distribution.
Millets are receiving renewed attention due to their short growing cycles, resilience and role as fodder and summer cereals. As C4 plants adapted to arid and tropical environments, millets were domesticated in East Asia and Africa, with species such as broomcorn millet spreading into Europe during the Bronze Age. In European archaeology, millets are key indicators of crop diversification among human communities, including in northern Italy. Archaeological evidence of their use derives from charred grains, phytoliths and stable isotope and molecular biomarkers analyses. Among molecular biomarkers, miliacin (olean-18-en-3β-ol methyl ether) has been widely recognised as a biomarker for Panicum miliaceum (L.)/broomcorn millet detected in pottery, sediments and charred residues. Carbon enrichment typical of C4 plants in Middle Late Bronze Age human remains has often been linked to millet consumption, although wild panicoid grasses may also have contributed to these isotopic signals. Among wild panicoid grasses, generally more difficult to trace archaeologically, Echinochloa crus-galli (L.) P. Beauv./barnyard grass represents an exception since its charred grains have often been found. This study investigates crusgallin (taraxer-14-en-3β-ol methyl ether) as a potential biomarker for barnyard grass. Different anatomical parts of modern plants were chemically analysed to determine crusgallin distribution, and the data were used as reference for the study of sediments from the Middle Bronze Age site of Oppeano 4D, where byre-houses containing herbivore dung and plant bedding were identified. Archaeobotanical deposits yielded abundant barnyard grass seeds together with miliacin and crusgallin, suggesting that these biomarkers may derive from both plant remains and herbivore dung, additionally indicating millets as possible components of animal fodder.
