Search Results (668)

Orbital flybys have been extensively studied for spacecraft missions, resulting in effective mathematical and physical models. However, these models’ applicability to natural encounters involving asteroids has not been explored. This paper examines the applicability of two such theories, patched conics (PC) and the Keplerian map (KM), to asteroid encounters. A review of the two methods will be provided, highlighting their assumptions and range of applicability. Simulations of asteroid–asteroid encounters will then be performed to evaluate their effectiveness in these scenarios. The simulation parameters are set by collecting data on actual asteroid–asteroid encounters, hereby presented, generally characterised by high close approach distances and small masses of the perturbing bodies, if compared to those used to build the flyby theories. Results show that the PC theory’s effectiveness diminishes with increasing approach distances, aligning with its assumptions. Moreover, the prediction of the model is better in the geometric configurations where the flyby has major effects on the orbital energy change. The KM theory has shown good effectiveness for encounters occurring outside the sphere of influence of the perturbing body, even for very high distances. This research investigates flyby models’ strengths and weaknesses in asteroid encounters, offering practical insights and future directions. Full article

The Imaging X-ray Polarimetry Explorer (IXPE) has confirmed that X-ray polarimetry is a valuable tool in astronomy, providing critical insights into the emission processes and the geometry of compact objects. IXPE was designed to be sensitive in the 2–8 keV energy range for three primary reasons: (1) celestial X-ray sources are bright within this range, (2) the optics are effective, and (3) most sources across various classes were expected to exhibit some level of polarization. Indeed, IXPE is a great success, and its discoveries are necessitating the revision of many theoretical models for numerous sources. However, one of IXPE’s main limitations is its relatively narrow energy band, coupled with rapidly declining efficiency. In this paper, we will demonstrate the benefits of devising a mission focused on a broader energy band (0.1–79 keV). This approach leverages current technologies that align well with theoretical expectations and builds on the successes of IXPE. Full article

The location of Electric Vehicle Charging Stations (EVCSs) is gaining significant importance as part of the conversion to a full-electric vehicle fleet. Positive or negative impacts can be generated mainly based on the quality of service offered to customers and operational efficiency, also potentially involving the electrical grid to which the EVCSs are connected. The EVCS location problem requires an in-depth and comprehensive analysis of geographical, market, urban planning, and operational aspects that can lead to several potential alternatives to be evaluated with respect to a defined number of features. This paper discusses the possible use of a multi-criteria decision-making approach, considering the differences between multi-objective decision making (MODM) and multi-attribute decision-making (MADM), to address the EVCS location problem. The conceptual evaluation leads to the conclusion that the MADM approach is more suitable than MODM for the specific problem. The identification of suitable attributes and related features is then carried out based on a systematic literature review. For each attribute, the relative importance of the features is obtained by considering the occurrence and the dedicated weights. The results provide the identification of the most used attributes and the categorization of the selected features to shape the proposed MADM framework for the location of the electric vehicle charging infrastructure. Full article

The laser station (BORL) owned by the Space Research Centre of the Polish Academy of Sciences and situated at the Astrogeodynamic Observatory in Borowiec near Poznań regularly observes more than 100 different objects in low Earth orbit (LEO) and medium Earth orbit (MEO). The BORL sensor’s laser observation range is from 400 km to 24,500 km. The laser measurements taken by the BORL sensor are utilized to create various products, including the geocentric positions and movements of ground stations, satellite orbits, the components of the Earth’s gravitational field and their changes over time, Earth’s orientation parameters (EOPs), and the validation of the precise Galileo orbits derived using microwave measurements, among others. These products are essential for supporting local and global geodetic and geophysics research related to time. They are crucial for the International Terrestrial Reference Frame (ITRF), which is managed by the International Earth Rotation and Reference Systems Service (IERS). In 2023, the BORL laser station expanded its list of tracked objects to include all satellites of the European satellite navigation system GALILEO, totaling 28 satellites. During that year, the BORL laser station recorded 77 successful passes of GALILEO satellites, covering a total of 21 objects. The measurements taken allowed for the registration of 7419 returns, resulting in 342 normal points. The average RMS for all successful GALILEO observations in 2023 was 13.5 mm. Full article

This study aimed to introduce specific image feature analysis, focusing on pancreatic margins, and to provide a quantitative measure of edge irregularity, evidencing correlations with the presence/absence of pancreatic adenocarcinoma. We selected 50 patients (36 men, 14 women; mean age 63.7 years) who underwent Multi-detector computed tomography (MDCT) for the staging of pancreatic adenocarcinoma of the tail of the pancreas. Computer-assisted quantitative edge analysis was performed on the border fragments in MDCT images of neoplastic and healthy glandular parenchyma, from which we obtained the root mean square deviation SD of the actual border from the average boundary line. The SD values relative to healthy and neoplastic borders were compared using a paired t-test. A significant SD difference was observed between healthy and neoplastic borders. A threshold SD value was also found, enabling the differentiation of adenocarcinoma with 96% specificity and sensitivity. We introduced a quantitative measure of boundary irregularity, which correlates with the presence/absence of pancreatic adenocarcinoma. Quantitative edge analysis can be promptly performed on select border fragments in MDCT images, providing a useful supporting tool for diagnostics and a possible starting point for machine learning recognition based on lower-dimensional feature space. Full article

Fluorine is one of the most interesting elements in nuclear astrophysics. Its abundance can provide important hints to constrain the stellar models since fluorine production and destruction are strictly connected to the physical conditions inside the stars. The ${}^{19}\mathrm{F}$(p,α)¹⁶O reaction is one of the fluorine burning processes and the correction evaluation of its reaction rate is of pivotal importance to evaluate the fluorine abundance. Moreover, the ${}^{19}\mathrm{F}$(p,α)¹⁶O reaction rate can have an impact for the production of calcium in the first-generation of Population III stars. Here, we present the AsFiN collaboration efforts to the study of the ${}^{19}\mathrm{F}$(p,$\alpha$)¹⁶O reaction by means of direct and indirect measurements. On the direct measurements side, an experimental campaign aimed to the measurement of the ${}^{19}\mathrm{F}$(p,${\alpha }_{0,\pi }$)¹⁶O reaction is ongoing, taking advantage of the new versatile arrays of silicon strip detectors, LHASA and ELISSA. Moreover, the Trojan Horse Method (THM) was used to determine the ${}^{19}\mathrm{F}$(p,${\alpha }_0$)¹⁶O reaction S(E)-factor in the energy range of astrophysical interest (${\mathrm{E}}_{cm}$≈ 0–1 MeV), showing, for the first time, the presence of resonant structures within the astrophysical energy range. THM has been also applied for the study of the ${}^{19}\mathrm{F}$(p,${\alpha }_{\pi }$)¹⁶O reaction; data analysis is ongoing. Full article

At present, one of the main challenges that industry faces is its impact on global warming, linked to the greenhouse effect and ozone hole problems. These two environmental issues have not yet been solved completely and, concerning the industrial cold sector, countries are making various decisions on refrigerants. Magnetic refrigeration potentially represents a less impactful refrigeration technology. In this review, the physical basis of magnetic refrigeration is analysed, in order to propose this technology for industrial use. Full article

The impacts of climate change, excessive greenhouse gas emissions, and the current energy crisis have motivated the European Union to adopt mitigation and adaptation strategies. These strategies primarily focus on the building sector due to its crucial role in addressing these issues. Among the strategies, the implementation of resilient technologies for the building envelope, such as vertical greenery systems (VGSs) is gaining ground. The literature analysis shows that existing models are not sufficiently detailed in their description of the overall thermo-physical phenomena of VGSs. The aim of this work is to overcome the research gaps by selecting and improving two mathematical models for green façades and living walls. A dedicated calculation code to estimate the effect of VGSs on a building’s energy performance and indoor thermal comfort has been developed and implemented within the EnergyPlus calculation software (version 23.2). A BESTest Case from ASHRAE 140 was chosen to test the models and to assess benefits of VGSs. The results show that adopting green solutions for the building envelope can contribute to achieving the building’s energy efficiency goals and that the modelling of these technologies can be easily carried out within a dynamic energy simulation of the building. Full article

Here, we reconsider the historical data, assuming a gamma-ray burst (GRB) as its source. A Supernova correlated with the GRB explains well the fading time observed by the ancient Chinese astronomers in the daytime and the nighttime, while the GRB power law explains the present X-rays and GeV emission of the Crab. On the grounds of a recent understanding of the first episode of binary-driven hypernova GRB (BDHN GRB) in terms of the collapse of a ten solar masses core, we propose the possible identification of the real Supernova event at an earlier time than Chinese chronicles. This work allows a new understanding of the significance of historical astronomical observations, including a fireball due to gamma-ray air shower observation and a plague of acute radiation syndrome, documented with several thousands of victims in the Eurasian area (Egypt, Iraq, and Syria). Full article

The Renewable Energy Community (REC) in Europe promotes renewable energy sources (RESs), offering social, economic, and environmental benefits. This new entity could alter consumer energy relationships, requiring self-consumption, energy sharing, and full utilization of RESs. Modernizing energy systems within the REC requires addressing self-consumption, energy sharing, demand response, and energy management system initiatives. The paper discusses the role of decentralized energy systems, the scenarios of the REC concept and key aspects, and activities involving energy generation, energy consumption, energy storage systems, energy sharing, and EV technologies. Moreover, the present work highlights the research gap in the existing literature and the necessity of addressing the technological elements. It also highlights that there is no uniform architecture or model for the REC, like in the case of microgrids. Additionally, the present work emphasizes the role and importance of technological elements in RECs, suggesting future recommendations for EMS, DSM, data monitoring and analytics, communication systems, and the software or tools to ensure reliability, efficiency, economic, and environmental measures. The authors also highlight the crucial role of policymakers and relevant policies, which could help in implementing these technological elements and show the importance of the RECs for a sustainable energy shift and transition. Full article

With the modernization of global navigation satellite systems (GNSS), especially the rapid development of the BeiDou Navigation Satellite System (BDS), more observations of satellites and signals have become available. Using data of the globally distributed MGEX stations, a systematic and comprehensive evaluation of signal characteristics for BDS-3, BDS-2, GPS, and Galileo is conducted in terms of carrier-to-noise ratio (C/N0), code noise, and multipath in the contribution. First, a comprehensive signal quality assessment method for BDS/Galileo/GPS satellites and signals is proposed, including C/N0 modeling and MP modeling. For BDS, the BDS-3 satellites apparently have higher signal power than the BDS-2 satellites at the same frequency such as B1I and B3I, and the signal B2a of BDS-3 is superior to other signals in regard to signal power, which is comparable with the superior Galileo E5 signals and GPS L5. Among all the signals, the observation accuracy of E5 is the highest regardless of receiver types, and next highest are BDS-3 B2a and GPS L5. Due to not being affected by the systematic code errors of BDS-2, the observations of BDS-3 satellites contain smaller multipath errors than that of BDS-2 satellites. As for the multipath suppression performance, the BDS-3 signal B2a, GPS L5, and Galileo E5 and E5b perform better than the other signals, which may be related to their wide signal bandwidths. Full article

The Global Navigation Satellite System (GNSS) software-defined receivers offer greater flexibility, cost-effectiveness, customization, and integration capabilities compared to traditional hardware-based receivers, making them essential for a wide range of applications. The continuous evolution of GNSS research and the availability of new features require these software-defined receivers to upgrade continuously to facilitate the latest requirements. The Finnish Geospatial Research Institute (FGI) has been supporting the GNSS research community with its open-source implementations, such as a MATLAB-based GNSS software-defined receiver `FGI-GSRx’ and a Python-based implementation `FGI-OSNMA’ for utilizing Galileo’s Open Service Navigation Message Authentication (OSNMA). In this context, longer datasets are crucial for GNSS software-defined receivers to support adaptation, optimization, and facilitate testing to investigate and develop future-proof receiver capabilities. In this paper, we present an updated version of FGI-GSRx, namely, FGI-GSRx-v2.0.0, which is also available as an open-source resource for the research community. FGI-GSRx-v2.0.0 offers improved performance as compared to its previous version, especially for the execution of long datasets. This is carried out by optimizing the receiver’s functionality and offering a newly added parallel processing feature to ensure faster capabilities to process the raw GNSS data. This paper also presents an analysis of some key design aspects of previous and current versions of FGI-GSRx for a better insight into the receiver’s functionalities. The results show that FGI-GSRx-v2.0.0 offers about a 40% run time execution improvement over FGI-GSRx-v1.0.0 in the case of the sequential processing mode and about a 59% improvement in the case of the parallel processing mode, with 17 GNSS satellites from GPS and Galileo. In addition, an attempt is made to execute v2.0.0 with MATLAB’s own parallel computing toolbox. A detailed performance comparison reveals an improvement of about 43% in execution time over the v2.0.0 parallel processing mode for the same GNSS scenario. Full article

This paper presents a historical overview of conceptions about the Sun in Western astronomical and cosmological traditions before the advent of spectroscopy and astrophysics. Rather than studying general cultural ideas, we focus on the concepts developed by astronomers or by natural philosophers impacting astronomy. The ideas we investigate, from the works of Plato and Aristotle to William Herschel and his contemporaries, do not line up into a continuous and integrated narrative, since the nature of the Sun was not a genuine scientific topic before the nineteenth century. However, the question recurringly arose as embedded in cosmological and physical contexts. By outlining this heterogeneous story that spreads from transcendence to materiality, from metaphysics to physics, from divinity to solar inhabitants, we receive insight into some major themes and trends both in the general development of astronomical and cosmological thought and in the prehistory of modern solar science. Full article

The recent advances achieved in additive manufacturing (AM) technology demonstrate the potential to realize customized metal components, ensuring weight reduction opportunities. These benefits make AM attractive for high-cost aerospace applications, especially where high geometric complexity is required. In the context of an EU research scenario, the H2020 MANUELA (Additive Manufacturing Using Metal Pilot Line) project promotes the development of new technologies for design optimization by enabling the application of novel materials in AM. This paper illustrates recent advances in a new aluminum alloy (Al-HS1) with high strength emphasizing all of the characterization steps at the coupon level. This material has been employed in the re-engineering of a conventional hydraulic manifold using a powder bed fusion-laser beam (PBF-LB) process. Both the simulations and structural tests allowed for proving its compliance and technological maturity with industrial standards and applicable airworthiness requirements. Full article

Background and Objectives: Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. Accumulating evidence in animal models suggests that loss of interleukin-10 (IL-10) anti-inflammatory actions might contribute to lobular inflammation, considered one of the first steps toward NASH development. However, the role of IL-10 in lobular inflammation remains poorly explored in humans. We examined mRNA and protein levels of IL-10 in liver biopsies and serum samples from morbidly obese patients, investigating the relationship between IL-10 and lobular inflammation degree. Materials and Methods: We prospectively enrolled morbidly obese patients of both sexes, assessing the lobular inflammation grade by the Brunt scoring system to categorize participants into mild (n = 7), moderate (n = 19), or severe (n = 13) lobular inflammation groups. We quantified the hepatic mRNA expression of IL-10 by quantitative polymerase chain reaction and protein IL-10 levels in liver and serum samples by Luminex Assay. We estimated statistical differences by one-way analysis of variance (ANOVA) and Tukey’s multiple comparison test. Results: The hepatic expression of IL-10 significantly diminished in patients with severe lobular inflammation compared with the moderate lobular inflammation group (p = 0.01). The hepatic IL-10 protein levels decreased in patients with moderate or severe lobular inflammation compared with the mild lobular inflammation group (p = 0.008 and p = 0.0008, respectively). In circulation, IL-10 also significantly decreased in subjects with moderate or severe lobular inflammation compared with the mild lobular inflammation group (p = 0.005 and p < 0.0001, respectively). Conclusions: In liver biopsies and serum samples of morbidly obese patients, the protein levels of IL-10 progressively decrease as lobular inflammation increases, supporting the hypothesis that lobular inflammation develops because of the loss of the IL-10-mediated anti-inflammatory counterbalance. Full article