12064 research outputs found
Sort by
Effects of hydrogen blending and exhaust gas recirculation on NOx emissions in laminar and turbulent CH4/Air flames at 25 bar
No full textIn this work, the effect of Exhaust Gas Recirculation (EGR) on NOx emissions in a CH4/H2/air combustion at 25 bar, at an equivalence ratio Φ = 0.7, is analyzed in laminar and turbulent partially premixed flames. Numerical simulations of twenty premixed and partially premixed counterflow flames with H2 ranging from 0 to 100%, with and without EGR, are carried out. Analysis of NO formation mechanisms shows that the thermal path is the main responsible for the NOx production in each flame, with a contribution of nearly 80%. In laminar flames an increase of H2 leads to an increase in NOx emissions. The addition of the exhaust gas decreases the flame temperature and therefore NOx: each laminar flame shows a NOx reduction of about 60% with the presence of exhaust gas. Four turbulent slot jet flames with a CH4/H2/Air/EGR premixed central core and Air/EGR as coflow are studied in a two-dimensional framework using the Reynolds Averaged Navier–Stokes (RANS) approach and the Large Eddy Simulation (LES) methodology, to take into account some flame dynamics, despite the 2D context. Accurate molecular transport properties are considered and, a reduced specifically designed chemical mechanism for methane/hydrogen-air combustion at Φ=0.7, consisting of 48 transported species and 465 elementary reactions is adopted. The four turbulent flames were simulated with 0 and 50% hydrogen concentration, with and without EGR. The presence of hydrogen reduces CO2 emissions, but at the same time increases NO concentration, the thermal path being the main NO formation mechanism. The use of exhaust gas recirculation leads to NO reduction as in laminar flames. The results obtained in this work show that at high pressure, the hydrogen enrichment of natural gas in the EGR mode leads to lower NOx as well as CO2 emissions
Operational Insights and Future Potential of the Database for Positive Energy Districts
No full textThis paper presents the Positive Energy District Database (PED DB), a pivotal web tool developed collaboratively by the COST Action ‘PED-EU-NET’, in alignment with international initiatives such as JPI Urban Europe and IEA EBC Annex 83. The PED DB represents a crucial step towards sharing knowledge, promoting collaboration, reinforcing decision-making, and advancing the understanding of Positive Energy Districts (PEDs) in the pursuit of sustainable urban environments. The PED DB aims to comprehensively map and disseminate information on PEDs across Europe, serving as a dynamic resource for sustainable urban development according to the objective of making the EU climate-neutral by 2050. Indeed, PEDs imply an integrated approach for designing urban areas—the districts—where a cluster of interconnected buildings and energy communities produce net zero greenhouse gas emissions, managing an annual local/regional overflow production of renewable energy. The paper describes the collaborative step-by-step process leading to the PED DB implementation, the current results and potentials of the online platform, and introduces its future developments towards a more user-friendly and stakeholders-tailored tool. The interactive web map offers a customizable visualizations and filters on multiple information related to PED case studies, PED-relevant cases, and PED Labs. Users can access detailed information through a table view, facilitating comparisons across different PED projects and their implementation phase. The paper offers insights and detailed analysis from the initial dataset that includes 23 PED cases and 7 PED-related projects from 13 European countries, highlighting the key characteristics of surveyed PEDs
Final results of the first phase of the PROTO-SPHERA experiment: obtainment of the full current stable screw pinch and first evidences of the jet + torus combined plasma configuration
No full textIn astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 225], on the other hand, in laboratory plasma experiments the electromagnetic boundary conditions become a major problem in the set-up of the machine that produces the plasma, an issue that has to be investigated step by step and to be modified and adapted with great patience, in particular in the case of an innovative plasma confinement experiment. The PROTO-SPHERA machine [Alladio F et al 2006 Nucl. Fusion 46 S613] is a magnetic confinement experiment, that emulates in the laboratory the jet + torus plasma configurations often observed in astrophysics: an inner magnetized jet of plasma centered on the (approximate) axis of symmetry and surrounded by a magnetized plasma torus orthogonal to this jet. The PROTO-SPHERA plasma is simply connected, i.e., no metal current conducting rod is linked to the plasma torus, while instead it is the inner magnetized plasma jet (in the following always called the plasma centerpost) that is linked to the torus. It is mandatory that no spurious plasma current path modifies the optimal shape of the plasma centerpost. Moreover, as the plasma torus is produced and sustained, in absence of any applied inductive electric field, by the inner plasma centerpost through magnetic reconnections [Taylor J B and Turner M F 1989 Nucl. Fusion 29 219], it is required as well that spurious current paths do not surround the torus on its outboard, in order not to lower the efficiency of the magnetic reconnections that maintain the plasma torus at the expense of the plasma centerpost. Boundary conditions have been corrected, up to the point that the first sustainment in steady state has been achieved for the combined plasma
Culturomics- and metagenomics-based insights into the soil microbiome preservation and application for sustainable agriculture
No full textSoil health is crucial for global food production in the context of an ever-growing global population. Microbiomes, a combination of microorganisms and their activities, play a pivotal role by biodegrading contaminants, maintaining soil structure, controlling nutrients’ cycles, and regulating the plant responses to biotic and abiotic stresses. Microbiome-based solutions along the soil-plant continuum, and their scaling up from laboratory experiments to field applications, hold promise for enhancing agricultural sustainability by harnessing the power of microbial consortia. Synthetic microbial communities, i.e., selected microbial consortia, are designed to perform specific functions. In contrast, natural communities leverage indigenous microbial populations that are adapted to local soil conditions, promoting ecosystem resilience, and reducing reliance on external inputs. The identification of microbial indicators requires a holistic approach. It is fundamental for current understanding the soil health status and for providing a comprehensive assessment of sustainable land management practices and conservation efforts. Recent advancements in molecular technologies, such as high-throughput sequencing, revealed the incredible diversity of soil microbiomes. On one hand, metagenomic sequencing allows the characterization of the entire genetic composition of soil microbiomes, and the examination of their functional potential and ecological roles; on the other hand, culturomics-based approaches and metabolic fingerprinting offer complementary information by providing snapshots of microbial diversity and metabolic activities both in and ex-situ. Long-term storage and cryopreservation of mixed culture and whole microbiome are crucial to maintain the originality of the sample in microbiome biobanking and for the development and application of microbiome-based innovation. This review aims to elucidate the available approaches to characterize diversity, function, and resilience of soil microbial communities and to develop microbiome-based solutions that can pave the way for harnessing nature’s untapped resources to cultivate crops in healthy soils, to enhance plant resilience to abiotic and biotic stresses, and to shape thriving ecosystems unlocking the potential of soil microbiomes is key to sustainable agriculture. Improving management practices by incorporating beneficial microbial consortia, and promoting resilience to climate change by facilitating adaptive strategies with respect to environmental conditions are the global challenges of the future to address the issues of climate change, land degradation and food security
Kinetic modeling of the plasma-wall interaction in the DTT divertor region
No full textA precise estimate of the local energy fluxes and erosion profiles at the divertor monoblocks of a fusion reactor requires a kinetic modeling of the plasma-wall interaction. Here, a two-dimensional Particle-in-Cell code is used to quantify the particle and energy fluxes and ion impact distribution functions across the divertor monoblocks of the ‘Divertor Tokamak Test’ reactor, focusing on poloidal gaps with toroidal bevelling. The considered critical locations are close to the strike points at both Inner and Outer Vertical Targets. A worst-case scenario for particle fluxes corresponding to attached plasma conditions and featuring a single-null magnetic configuration is assumed. The separate and cumulative effects of including electron wall emission and ions/electrons collisions with a background neutral gas (recycled at the walls) are also assessed. It is found that a non-negligible energy flux affects the shadowed regions of the monoblocks, especially when accounting for collisions, and that the ion impact distribution functions are strongly influenced by the considered kinetic effects, with important implications on the induced sputtering yield
A systematic literature review exploring the nexus between circular economy and communities
No full textCircular Economy (CE) studies often focus primarily on technical and economic aspects of the transition process. Recently, some authors have started to enquire the social processes connected to of the CE, often referring to communities. This article provides a Systematic Literature Review on the nexus between CE and community to investigate its features according to the experiences reported in the collected documents. The retrieved corpus has been analyzed recurring to consolidated frameworks, as the R hierarchy, the societal areas challenges identified by the Strategic Research and Innovation Agenda developed by the EU project CICERONE, and to the spectrum of participation provided by the International Association for Public Participation. The participative dynamics found in the corpus are analyzed also considering the type of communities, tools, methodologies and goals reported in the retrieved documents. Besides descriptive statistics about the mentioned aspects, the article includes a discussion on some CE social aspects, problematizing and questioning the retrieved stakeholders engagement practices, recurring to a qualitatively selected literature. Conclusions address the main findings related to the most commonly found R strategy, community type, societal challenge areas and type of participative dynamics according to the analytical components chosen in the methodology. Research implications are illustrated, suggesting possible directions for future research to widen the analysis on the nexus between CE and communities
Design of a position monitoring system for the ITER radial neutron camera
Get PDFThe Radial Neutron Camera (RNC) is an ITER diagnostic system devoted to the radial measurement of the plasma neutron emissivity during ITER operation. In particular, plasma core measurements will be performed using 48 detectors located in the Ex-Port RNC subsystem and viewing the plasma through 16 lines-of-sight (LOS). Since discrepancies concerning the position of the LOS and the related optical path can occur during RNC installation and ITER operation, a Position Monitoring System (PMS) is foreseen to evaluate the misalignment and provide a correction tool for the neutrons count rate. During the design of the PMS for the RNC, optic fiber-based displacement sensors have been identified as the best solution to measure the displacements from reference positions along the radial, vertical and toroidal directions. Potential issues that could arise during the installation and operation of such sensors have been evaluated; MCNP calculations have been performed to determine the radiation level at the position of the PMS components. Finally, mechanical tests have been carried out at ENEA to evaluate the performance of the sensors: results indicate compliance with the specifications provided by the producer and the ITER RNC design requirements
Exploring the potential of laser photoacoustic spectroscopy (LPAS) for predicting amylose content in rice flour
Get PDFRice, one of the most widely consumed staple foods globally, relies on amylose content for its quality, impacting cooking, digestibility, and health properties. Conventional amylose determination methods are time-consuming and involve complex chemical treatments. Thus, there is growing interest in rapid, non-destructive techniques for food quality control. This study explores the potential of laser photoacoustic spectroscopy (LPAS) for predicting amylose content in rice flour
Analysis of glycoalkaloid distribution in the tissues of mealworm larvae (Tenebrio molitor)
Get PDFSolanine (SOL) and chaconine (CHA) are glycoalkaloids (GAs) produced mainly by Solanum plants. These plant secondary metabolites affect insect metabolism; thus, they have the potential to be applied as natural plant protection products. However, it is not known which GA concentration induces physiological changes in animals. Therefore, the aim of this study was to perform a quantitative analysis of SOL and CHA in the larvae of Tenebrio molitor using LC‒MS to assess how quickly they are eliminated or metabolised. In this experiment, the beetles were injected with 2 μL of 10−5 M SOL or CHA solution, which corresponds to a dosage range of 0.12–0.14 ng/mg body mass. Then, 0.5, 1.5, 8, and 24 h after GA application, the haemolymph (H), gut (G), and the remainder of the larval body (FB) were isolated. GAs were detected in all samples tested for 24 h, with the highest percentage of the amount applied in the FB, while the highest concentration was measured in the H sample. The SOL and CHA concentrations decreased in the haemolymph over time, while they did not change in other tissues. CHA had the highest elimination rate immediately after injection, while SOL slightly later. None of the GA hydrolysis products were detected in the tested samples. One possible mechanism of the detoxification of GAs may be oxidation and/or sequestration. They may be excreted by Malpighian tubules, with faeces or with cuticles during moulting. The results presented are significant because they facilitate the interpretation of studies related to the effects of toxic substances on insect metabolism
Recent progress of JT-60SA project toward plasma operation
Get PDFSuperconducting (SC) tokamak JT-60SA plays an essential role in fusion research and development by supporting and complementing the ITER project, providing directions to the DEMO design activity and fostering next generation scientists and engineers. Since the short circuit incident at the terminal joints of equilibrium field coil #1 during the integrated commissioning (IC) in March 2021, both EU and JA implementing agencies (IAs) have examined how to ensure safe operation of JT-60SA by mitigating the risk of possible discharge occurrence inside the cryostat. Based on the experience of the global Paschen tests, the IAs have established a strategy of risk mitigation measures, which is a combination of (i) reinforcement of insulation, (ii) avoiding unnecessary voltage application to the coil systems and (iii) immediate de-energization of the coils when deteriorated vacuum conditions are detected. Thanks to the considerable efforts of the Integrated Project Team members, the IC restarted in May 2023. After confirmation of the SC state of the coil systems (TF, EF and CS), the coil energization test and the plasma operation phase 1 (OP-1) started. The first plasma was successfully achieved on 23 October 2023 with a limited value of voltage and current applied to the coils. The plasma configuration control was also confirmed with low plasma current and low auxiliary heating power conditions. Based on the IO-F4E-QST collaboration, activities of JT-60SA have been shared with the IO and provided an important lesson for ITER assembly and commissioning, and will provide an outstanding contribution to fusion research at large. After OP-1, maintenance & enhancement phase 1 (M/E-1) starts from January 2024, in which in-vessel components are installed, and heating and diagnostic systems are extensively upgraded to allow a high power heating experiment planned in OP-2. In order to make the best use of JT-60SA, a newly organized JT-60SA experiment team will refine the research plan for the future high heating power operation phase