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Preliminary thermal and structural analyses on the parabolic mirror of the Multi-Beam Transmission Line of the DTT ECH system
Full text linkThe Italian tokamak DTT (Divertor Tokamak Test) is a facility for research on nuclear fusion with the aim of investigating alternative power exhaust solutions to be exploited in the future DEMO fusion power plant. DTT foresees three additional heating systems to provide the plasma with sufficient power: Electron Cyclotron Heating (ECH) is the main one, with up to 32 MW installed. It consists of 4 clusters, each one composed of eight radio-frequency sources (gyrotrons) with their single-beam transmission lines, one quasi-optical Multi-Beam Transmission Line (MBTL) and eight independent launchers. The power produced by the source is transmitted quasi-optically through multiple reflections on metallic mirrors, the basic component of the transmission line, and then injected into the plasma. In the MBTL the reflection of the eight microwave beams on the mirror surface leads to heating of its whole structure due to the absorbed fraction of the beam power (0.21–0.27 %) ascribed to the ohmic heating at the mirror surface. During the radio-frequency power pulse (100 s), the mirror temperature increases, generating deformations that could result in a loss of beam transmission efficiency. For this reason, these mirrors need to be carefully designed from thermal and structural points of view, to guarantee the required optical performances. In the present paper, a preliminary study concerning the design of the MBTL parabolic mirror, and its cooling is presented, resorting to a coupled thermal and structural finite element simulation. The preliminary analyses address a main objective: minimize the surface mirror temperatures and consequently the deformation associated with thermal expansion, to reduce the impact on beam transmission efficiency drop. Different design choices, namely materials, body thickness and cooling solutions, in terms of cooling channel shape and water flow, are discussed
Primary Quench Detection Analysis for the EU-DEMO Toroidal Field Coils
No full textTo protect the Toroidal Field Coils (TFC) of the EU DEMO tokamak, in case it will be realized with low temperature superconducting (LTS) materials, a reliable and fast quench detection system (QDS) is required. Although these TFC coils are operated in static mode, voltages across their winding pack (WP) will be generated during machine operation due to the presence of dynamic magnetic fields. Two sources of magnetic coupling, responsible for noisy signals on the quench detection circuitry in a Fast Plasma Disruption scenario, are here considered and analyzed. Due to the high electromagnetic noise environment, the co-wound (CW) technology must be adopted for the quench sensors and an aligned and twisted layout (CWA&T) is necessary due to the magnetic interaction with the superconductor (SC) strand helicity. The poloidal component of the plasma current is responsible for a noisy signal on the CW and a strategy for signal compensation will be suggested and the contribution evaluated numerically. The signal induced on a SC cable due to the helicity can be compensated adopting a CWA&T configuration. The twist pitch length (TP) of the CWA&T is a critical parameter for a proper noise compensation. Since it is challenging to obtain a reliable TP length from a numerical simulation, we here propose an experimental approach to assess the proper TP length. There is not a constraint on the TP length from the poloidal plasma current induced signal and we can conclude that a single TP, optimized for helicity compensation, will be sufficient
Green Anisole as Antisolvent in Planar Triple-Cation Perovskite Solar Cells with Varying Cesium Concentrations
No full textThe feasibility of replacing toxic chlorobenzene antisolvents with environmentally friendly anisole in the fabrication of planar triple-cation perovskite solar cells was explored here. The successful integration of anisole not only ensures comparable device performance but also contributes to the development of more sustainable and green fabrication processes for next-generation photovoltaic technologies. Nevertheless, to ensure the possibility of achieving well-functioning unencapsulated devices whose working operation depends on outdoor atmospheric conditions, we found that adjusting the cesium concentrations in the perovskite layers enabled the electrical characterization of efficient devices even under high relative humidity conditions (more than 40%). We found that 10% of CsI in the precursor solution will make devices with low hysteresis indexes and sustained performance stability over a 90-day period both with cholorobenzene and anisole antisolvent. These results further confirm that green anisole can replace chlorobenzene as an antisolvent
Detailed Microstructural Investigation of Oxidation Phenomena in 1144 FBS
No full textThe 1144 phase (Ae1A1Fe4As4) shows a strong advantage of engineering fabrication among Fe (Iron)-based superconductor (FBS) family due to the robustness of its superconducting properties with respect to chemical inhomogeneities, granted by its stoichiometric nature. This regularity is furthermore associated to defects capable of acting as efficient pinning centers with high critical currents achieved at high fields for these superconductors. Like other FBS phases, its lossless current-carrying capability can be remarkably degraded by distractions at grain boundaries (GBs). GB oxidation is an issue of upmost importance to the realization of the practical FBS application for high field (>20 T) magnet. In this study, we explore oxidized grain boundary and intrinsic grain structural properties of 1144 polycrystalline samples by applying analytical electron microscopy such as atomic resolution scanning transmission electron microscopy and atom probe tomography. These structural properties of 1144 samples are evaluated following the degradation of superconducting properties due to oxidation. We observe a strong correlation between the contamination at grain boundaries and the decrease of transport properties of the bulk sample, while the bulk crystalline structure is not affected by the oxidation. crystallin
The Hunga Tonga–Hunga Haʻapai volcanic barometric pressure pulse and meteotsunami travel recorded in several Antarctic stations
No full textThe Hunga Tonga–Hunga/Hunga-Haʻapai eruption on January 15, 2022 sent off a plume of ash material up to the stratosphere and triggered a meteotsunami and barometric pressure pulse that rippled through the atmosphere and oceans all around the world. The nature of the volcanic event and its global impacts on the oceans, atmosphere, lithosphere and the cryosphere are a matter of debate. Here we present a first overview of the time travel of the sound atmospheric pressure wave through the Antarctic continent based on in situ measurements, which represented a unique event observed through the polar ice sheet during the instrumental meteorological era. In addition, we estimated the tsunami travel time of the Hunga-Tonga event from a first order model to infer its impact over the Antarctic Sea ice and ice shelves. One outcome from our observations and modeling is the detection of the meteotsunami in the Antarctic Peninsula and the impact of the continental relief over the atmospheric pressure wave dispersion
High porosity-magnetic composite materials for magnetic induction swing adsorption (MISA): Improvement of performance properties
No full textA magnetic composite consisting of MOF HKUST-1 and magnetite nanoparticles was synthesized and successfully utilized for the separation of CO2 from N2/CO2 mixtures. The CO2 adsorbed by the porous material was successively desorbed by means of a recently proposed, high-efficiency technique so-called Magnetic Induction Swing Adsorption (MISA). The energy necessary to the desorption of carbon dioxide is transferred by electromagnetic induction to the magnetic nanoparticles that promptly dissipate it into heat. The composite material has been synthesized by growing the metal organic framework on functionalized magnetite nanoparticles by means of liquid assisted grinding (LAG) mechanochemical process. The composite material has been characterized in its morphological and functional properties. Thanks to improved magnetic properties, the optimized nanocomposite requires lower magnetic fields to desorb the CO2 and allows for reaching the same regeneration temperature in the sorbent bed at lower magnetic field amplitude, compared to previously synthesized composite materials. A regeneration energy Q of 4.4 MJ/kg CO2 has been calculated at 130 °C desorption temperature
A note on the magnetic multipole polynomials
No full textA family of two variable polynomials naturally emerges from the expansion in multipoles of a magnetic field. The order of the expansion fixes the polynomial degree and the multipolar content: dipole, quadrupole, sextupole and so on. The associated polynomials share analogies with Hermite-type families. The relevant properties are studied, within an umbral framework, which simplifies the derivation of the associated mathematical technicalities. We take advantage from this analogy to present a fairly general discussion about the properties of the “magnetic” polynomials. We touch on the possibility of embedding the results of the present study in a dedicated algorithm for the analysis of the transport of a charged beam in a magnetic structure
Role of Xenosialylation in Post-Infectious and Post-Vaccination Complications, Including Covid-19 and Anti-SARS-CoV-2 Vaccination
No full textThe host glycosylation mechanism, with sialic acids as a key component, is essential for synthesizing carbohydrate components in viral glycoproteins. We hypothesize a correlation between the presence of the Neu5Gc on the host tissue and the development of infectious complications, adverse vaccine reactions, and autoimmune diseases. In certain mammals, including humans, the loss of the Cytidine Monophospho-N-Acetylneuraminic Acid Hydroxylase gene (negative-CMAH) prevents the synthesis of Neu5Gc, which acts as a Mammalian-associated Carbohydrate Antigen (MCA), (XeSiAs-Neu5Gc). When negative-CMAH species consume products from positive-CMAH mammals or are exposed to non-human cell-derived medicines, Neu5Gc can be integrated into their glycocalyx through a process called xenosialylation, eliciting an inflammatory response (xenosialitis) and prompting the production of circulating anti-Neu5Gc antibodies aimed at eliminating Neu5Gc. We hypothesize that in the case of xenosialylation, neutralizing antiviral antibodies from infections or vaccinations—including those for SARS-CoV-2—may cross-react with the XeSiAs-Neu5Gc glycans, as these resemble viral envelope antigens produced by the host’s glycosylation. Additionally, circulating anti-Neu5Gc antibodies may also react with other circulating antibodies, including newly formed antiviral ones with a XeSiAs-Neu5Gc-contaminated Fc region. This can lead to the serum removal of the anti-inflammatory antibodies, leaving only hyperinflammatory IgG agalactosylated antibodies. Such conditions are also seen in various inflammatory and autoimmune diseases. We hypothesize that the combination of antibody cross-reaction and the removal of the XeSiAs-Neu5Gc-contaminated Fc region anti-inflammatory antibodies may intensify severe inflammatory responses like cytokine storms and coagulopathies in COVID-19 patients and those vaccinated. Assessing serum levels of total XeSiAs-Neu5Gc antibodies could be a valuable method for identifying patients at risk of severe complications from viral infections and vaccinations, including SARS-CoV-2. This strategy may also deepen our understanding of the pathogenesis of autoimmune diseases linked to post-infectious and post-vaccination complications, particularly for viruses utilizing the host glycosylation machinery, such as SARS-CoV-2, IAV, EBV, and others
Effect of Compost from Cardoon Biomass, as Partial Replacement of Peat, on the Production and Quality of Baby Leaf Lettuce
No full textThe use of peat, the standard substrate used for soilless cultivation of horticultural crops, is becoming of increasing concern as peat is a non-renewable resource and its extraction can degrade wetland ecosystems, creating a strong environmental impact. For this reason, the search for organic materials that can totally or partially replace peat has become increasingly important. In this research, three types of composts (C1, C2, C3), derived from cardoon biomass mixed in different volumes with woody and/or fruit wastes, were utilized as the constituents of growing media, at two dilution rates with peat (60:40 and 30:70 v:v), to assess their effect on the growth and quality of baby leaf lettuce in a greenhouse trial. The two cultivars Imperiale and Verde d’Inverno, belonging to the butterhead and romaine lettuce types, respectively, were employed. Plant performance and yield were unaffected or were positively affected by compost-containing growing medium compared to the control. The cultivars responded differently to the growing medium; the Imperiale showed the highest yield with C1 compost at a 60% rate while the Verde d’Inverno with the C2 was at 30%. The total chlorophyll, carotenoids, and ascorbic acid were found higher in the Verde d’Inverno than in the Imperiale variety while the total polyphenols, flavonoids, and antioxidant activity were lower. Also, the content of chlorophylls as well as of antioxidant compounds and antioxidant activity were differently affected by the growing medium, depending on the lettuce cultivar. The results obtained indicate that cultivated cardoon waste-based compost is a promising constituent of the growing media for baby leaf production. The specific varietal response observed should be considered to optimize both yield and product quality
Murine Skin Dosimetry Under Millimeter Wave Exposure
Full text linkThe upper part of the frequency spectrum (millimeter waves, MMW) applied by modern communications technologies (5G and beyond), makes skin the dominantly exposed tissue to electromagnetic fields. In this work, a methodology for murine skin dosimetry evaluation is presented, intended to contribute to animal studies with mice exposed to MMW radiation, in particular 27.5 GHz. A stratified skin model is proposed and the variations of the skin layers' thicknesses during a hair cycle are measured in mice. The variations of skin layers' dielectric properties due to age, based on the changes of total body water, are also evaluated. The impact of these variations in dosimetric metrics (i.e., mean absorbed power density, APD, and power loss) within each layer is assessed and found to be significant. Changes in the skin layers' thicknesses throughout a hair cycle considerably affect the APD, resulting in a two-fold increase, compared to changes in the dielectric properties due to aging or due to hair presence inside the skin