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Evaluation of RESRAD-BUILD and MicroShield codes for the simulation of small accident scenarios in nuclear medicine therapy patients’ rooms
No full textComputational methods in nuclear medicine therapy can be very useful for estimating the external dose in non-routine situations when conventional dosimeters may be inadequate or unavailable. Monte Carlo techniques provide the most accurate approach when it comes to model complex scenarios, but they are time and machine resource consuming. In this work we explore the alternative of using two fast and interactive deterministic codes, RESRAD-BUILD and MicroShield, primarily designed for radiation protection purposes, to calculate the dose in small, simple accidental scenarios, and benchmarked them with two Monte Carlo simulation tools, MCNP6 and Geant4. The absorbed dose rate in air computed by RESRAD-BUILD and compared to MicroShield showed a mean ratio of 1.01 ± 0.04 for Lu-177 and 0.99 ± 0.04 in the case of a point source and within 25% for an area source. When compared to MCNP6 and Geant4, the results revealed an overall agreement among the codes, showing a deviation below 30% in most cases, with a few exceptions that are discussed. We also propose a preliminary approach for easy modeling of patient's organs to calculate the external dose from routine therapies with deterministic methods. The suitability and limitation of these models are presented and discussed for some common applications
Scaling-up assessment of natural circulation phenomena in integral Small Modular Reactor by TRACE code
Get PDFSmall Modular Reactors (SMRs) adopting passive mitigation strategies are currently the most promising technology for the near term deployment of nuclear power generation. Different SMRs designs are currently under development and are, in general, characterized by some common features with the current reactors and by other features typical of their designs. Therefore, though numerous code validation study against natural circulation (NC) have been performed for large scale reactors, further analyses are necessary to characterize the capability of codes against available experimental data representative of SMR phenomenology. Though different scaling methodologies have been developed, considering the complex geometry and phenomena of a NPP, in the design of scaled-down experimental facilities it is not possible to avoid distortions, which should be limited to non-dominant phenomena. Even if dominant phenomena are preserved, due to the missing data at NPP scale, the code accuracy should be tested at different scales. Therefore, in a verification and validation process, the uncertainty related to the code scaling-up capability should be addressed, for example using counter-part tests. Since NC tests at different scales in integral test facilities devoted to SMR are currently not available, a numerical scaling methodology is here proposed. Based on previous activities, having as a reference the NC DOE tests developed in the OSU-MASLWR facility, the USNRC best estimate thermal hydraulic TRACE code has been validated for simulating NC in steady and transient conditions. Since the OSU-MASLWR is volume and height scaled, the target of this paper is to assess the scaling-up capability of the OSU-MASLWR Reactor Pressure Vessel nodalization in the prediction at different scales of NC and other phenomena typical of SMR, having as a base the OSU-MASLWR-002 single phase NC data. This, also, gives some first insights about the TRACE scaling-up capability against single-phase NC in integral type configurations
Comparative Analysis of Ground-Based Solar Irradiance Measurements and Copernicus Satellite Observations
Get PDFSolar irradiance data provided by the Copernicus program are crucial for several scientific, environmental, and energy management applications, but their validation by means of ground-based measurements may be necessary, especially if daily and hourly data resolutions are required. The validation process not only ensures that reliable information is available for solar energy resource planning, power plant performance assessment, and grid integration, but also contributes to the improvement of the Copernicus system itself. Ground-based stations offer site-specific data, allowing for comprehensive assessments of the system’s performance. This work presents a comparative statistical analysis of solar irradiance data provided by the Copernicus system and ground-based measurements on a seasonal basis at three specific Italian reference sites, showing a maximum average relative error of less than 7% for hourly horizontal global irradiance in the irradiance range defined by the IEC 61724-2
Validation and Application of Hysteresis Loss Model for HTS Stacks and Conductors for Fusion Applications
Get PDFNumerous conductor designs for pulsed magnets based on High Temperature Superconductors (HTS), featuring stacks of tapes are currently being proposed. A major contribution to the AC losses is expected to be given by hysteresis losses. Several numerical models have been developed for the computation of hysteresis losses, however the lack of experimental data in conditions relevant for the coil operation did not allow extensive validation of those models. Here, we present the AC loss tests performed on HTS conductor with transport current in conditions of partial or full field penetration. After the validation of a numerical model on those data, we analyze the losses expected during the operation of the EU DEMO CS coil, assessing possible analytical formulations for the calculation of hysteresis losses in DEMO-relevant conditions
Digitalizzazione nell'infrarosso ad alta risoluzione con sistema laser scanner prototipale IR-ITR degli affreschi altomedioevali conservati nella basilica paleocristiana di San Clemente, Roma
Get PDFUn esempio di applicazione delle nuove tecnologie, ed in particolare di quella laser scanner, nel campo dei beni culturali per la loro tutela, conservazione e fruizione viene descritto considerando il caso di studio delle pitture murali altomedioevali di particolare interesse storico-artistico conservate nella basilica paleocristiana di San Clemente (Roma). In particolare la digitalizzazione ad alta risoluzione nell’infrarosso di tali pitture effettuata con il sistema prototipale ENEA di laser scanner IR-ITR (Infrared Imaging Topological Radar) ed i risultati ottenuti vengono presentati e discussi come metodo innovativo e oggettivo d’indagine che può essere affiancato alle tecniche tradizionali per lo sviluppo di sistemi di analisi e di studio multidisciplinari. Questi ultimi consentono di rafforzare il sodalizio tra arte e tecnologia e di raggiungere un più alto livello di conoscenza, tutela, accessibilità e divulgazione delle opere d’arte di interesse. In tale contesto verrà descritta la campagna di misure svolta nell’ottobre 2023 con IR-ITR nella basilica paleocristiana di San Clemente con i relativi risultati ottenuti. Lo scopo di tali misure è stato quello di rilevare eventuali dettagli nascosti presenti nelle pitture murali altomedioevali non visibili ad occhio nudo o con tecniche operanti nel visibile, oltre che migliorare la leggibilità delle opere d’arte di interesse che presentano un cattivo stato di conservazione per favorirne il loro recupero parziale, almeno dal punto di vista digitale, e per consentire una loro corretta interpretazione storico-artistica laddove questa sia incertaAn example of application of new technologies, especially of the laser scanner one, in the field of cultural heritage for their safeguard, conservation and fruition is described considering the case study of early medieval wall paintings of special historical-artistic interest preserved in the early Christian basilica of San Clemente (Rome). Particularly, the high-resolution infrared digitalization of these paintings carried out by the ENEA prototype system of laser scanner named IR-ITR (Infrared Imaging Topological Radar) and the results obtained are presented and discussed as an innovative objective method of investigation that can be used along with traditional techniques for the development of multidisciplinary systems of analysis and study. These ones allow to strengthen the union between art and technology and to achieve a higher level of knowledge, safeguard, accessibility and dissemination of artworks under investigation. Within this framework, the field campaign carried out in October 2023 by means of the IR-ITR in the early Christian basilica of San Clemente will be described with the relative obtained results. The purpose of these measures was to detect hidden details eventually present in the early medieval wall paintings that are not visible to the naked eye or with techniques operating in the visible as well as to improve the legibility of the artworks of interest that are in a poor state of preservation in order to facilitate their partial recovery, at least from the digital point of view, and to allow their correct historical interpretation where this is uncertain
Thermal comfort monitoring in office buildings: A case study
Get PDFIn the framework of EPBD Directive revision, the EU is pushing Member States to pay more attention to IEQ conditions in buildings, by introducing specific requirements to be verified in the calculation methodology implemented in the national building codes. In this paper, the extensive field monitoring of an office building, carried out in the heating, cooling and intermediate seasons of 2022-2023, is described. Main thermo-hygrometric quantities have been measured in different rooms, considering the occupancy profile, users’ behaviour and appliances use. Results showed overheating conditions in offices exposed to the south façade, mainly due to solar radiation and internal heat gains. Surprisingly, north-facing offices with heating terminals running are colder than south-facing ones with HVAC systems turned off. Further differences were found in the temperature analysis of free-floating conditions, showing deviations up to 4 °C on average, between south and north facing rooms. For each room, thermal comfort issues were assessed in accordance with EN 16798-1, by calculating Fanger Indexes (PMV and PPD), and by adaptive method in the HVAC systems off-work periods. These findings represent the first results of an in-depth analysis of thermal comfort and IEQ conditions, aimed at assessing how the IEQ conditions can address the building energy audit, increasing, at the same time, energy performance and IEQ levels
Comparing the effects of irradiation with protons or photons on neonatal mouse brain: Apoptosis, oncogenesis and hippocampal alterations
No full textBackground and Purpose: Medulloblastoma (MB) is a common primary brain cancer in children. Proton therapy in pediatric MB is intensively studied and widely adopted. Compared to photon, proton radiations offer potential for reduced toxicity due to the characteristic Bragg Peak at the end of their path in tissue. The aim of this study was to compare the effects of irradiation with the same dose of protons or photons in Patched1 heterozygous knockout mice, a murine model predisposed to cancer and non-cancer radiogenic pathologies, including MB and lens opacity. Materials and Methods: TOP-IMPLART is a pulsed linear proton accelerator for proton therapy applications. We compared the long-term health effects of 3 Gy of protons or photons in neonatal mice exposed at postnatal day 2, during a peculiarly susceptible developmental phase of the cerebellum, lens, and hippocampus, to genotoxic stress. Results: Experimental testing of the 5 mm Spread-Out Bragg Peak (SOBP) proton beam, through evaluation of apoptotic response, confirmed that both cerebellum and hippocampus were within the SOBP irradiation field. While no differences in MB induction were observed after irradiation with protons or photons, lens opacity examination confirmed sparing of the lens after proton exposure. Marked differences in expression of neurogenesis-related genes and in neuroinflammation, but not in hippocampal neurogenesis, were observed after irradiation of wild-type mice with both radiation types. Conclusion. In-vivo experiments with radiosensitive mouse models improve our mechanistic understanding of the dependence of brain damage on radiation quality, thus having important implications in translational research
Corrosion on cultural heritage buildings in Jordan in current situation and in future climate scenarios
Get PDFThis study examines the impact of air pollution on Jordan’s cultural heritage sites, focusing on key pollutants (SO2, HNO3, O3, PM10) and climate conditions. Using 2019 data and future projections for 2040–2059 and 2080–2099, the research reveals significant material corrosion in urban areas like Amman and Irbid, driven by pollutants such as SO2 and PM10. Random Forest Analysis identifies these pollutants as primary contributors to material degradation. Future scenarios indicate corrosion rates exceeding safe limits across Jordan, underscoring the need for proactive conservation strategies. This work highlights the critical role of air quality management in protecting cultural heritage, especially under climate change pressures, and provides guidance for national policy development
Machine Learning and Weather Model Combination for PV Production Forecasting
Get PDFAccurate predictions of photovoltaic generation are essential for effectively managing power system resources, particularly in the face of high variability in solar radiation. This is especially crucial in microgrids and grids, where the proper operation of generation, load, and storage resources is necessary to avoid grid imbalance conditions. Therefore, the availability of reliable prediction models is of utmost importance. Authors address this issue investigating the potential benefits of a machine learning approach in combination with photovoltaic power forecasts generated using weather models. Several machine learning methods have been tested for the combined approach (linear model, Long Short-Term Memory, eXtreme Gradient Boosting, and the Light Gradient Boosting Machine). Among them, the linear models were demonstrated to be the most effective with at least an RMSE improvement of 3.7% in photovoltaic production forecasting, with respect to two numerical weather prediction based baseline methods. The conducted analysis shows how machine learning models can be used to refine the prediction of an already established PV generation forecast model and highlights the efficacy of linear models, even in a low-data regime as in the case of recently established plants
Joint effects of inter-specific and intra-specific diversity of tomato volatile profiles on antixenosis against Tuta absoluta
Get PDFSince volatile organic compounds (VOCs) shape plant defenses against pests, ecologists strive to understand their sources of variation. The worldwide distribution of tomato offers an ideal system to explore the ecological diversity of VOCs produced by plants supporting a large range of local adaptations. In this study, we analyzed the diversity of VOC profiles released by 29 accessions of tomato belonging to five species with different natural histories and including domesticated plants and wild relatives. In addition, olfactometer assays were performed on 10 accessions characterized by strong differences in VOC emissions to test the consequences on host-plant location by a major pest specialized on solanaceous plants, Tuta absoluta. Based on 77 VOCs detected, our results suggest that the large diversity of volatile profiles reflect different biogeographic areas. A phylogenetic tree was constructed to test phylogenetic drivers in VOC emissions. The richness of volatile profiles and sesquiterpenoid emissions were relatively high in ancestral branches and decreased exponentially with evolution according to early-burst patterns. In olfactometer assays, we identified four repellent accessions belonging to S. pennellii, S. habrochaites and S. cheesmaniae. This study points out the importance of inter-and intra-specific diversity of VOCs in antixenosis. Further, our results suggest that methyl salicylate, β-myrcene and sesquiterpenoids such as (3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene or α-curcumene could serve as repellents against T. absoluta. In a greenhouse, we confirmed the biological relevance of agroecological research interested in screening repellent plants. Bridging chemical ecology with phylogenetic approaches helps to better understand the evolution of mechanisms supporting anti-herbivore plant defenses