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Future Circular Collider Feasibility Study Report: Volume 3, Civil Engineering, Implementation and Sustainability: Volume 3 Civil Engineering, Implementation and Sustainability
No full textInternational audienceVolume 3 of the FCC Feasibility Report presents studies related to civil engineering, the development of a project implementation scenario, and environmental and sustainability aspects. The report details the iterative improvements made to the civil engineering concepts since 2018, taking into account subsurface conditions, accelerator and experiment requirements, and territorial considerations. It outlines a technically feasible and economically viable civil engineering configuration that serves as the baseline for detailed subsurface investigations, construction design, cost estimation, and project implementation planning. Additionally, the report highlights ongoing subsurface investigations in key areas to support the development of an improved 3D subsurface model of the region. The report describes development of the project scenario based on the 'avoid-reduce-compensate' iterative optimisation approach. The reference scenario balances optimal physics performance with territorial compatibility, implementation risks, and costs. Environmental field investigations covering almost 600 hectares of terrain - including numerous urban, economic, social, and technical aspects - confirmed the project's technical feasibility and contributed to the preparation of essential input documents for the formal project authorisation phase. The summary also highlights the initiation of public dialogue as part of the authorisation process. The results of a comprehensive socio-economic impact assessment, which included significant environmental effects, are presented. Even under the most conservative and stringent conditions, a positive benefit-cost ratio for the FCC-ee is obtained. Finally, the report provides a concise summary of the studies conducted to document the current state of the environment
Auroral Acceleration at the Northern Magnetic Pole During Sub‐Alfvénic Solar Wind Flow at Earth
No full textInternational audienceBetween 23 and 25 May 2002 the solar wind, due to very low plasma density, became sub-Alfvénic for enough time to promote the establishment of Alfvén wings that can limit typical solar windmagnetosphere coupling. During this interval, the interplanetary magnetic field (IMF) was oriented northward and duskward, with a slightly dominant B Y component; driving of the magnetosphere was expected to be low. Many signatures are used to assess solar wind-magnetosphere-ionosphere coupling, including ultraviolet (UV) observations of the auroral zone to infer monoenergetic electron precipitation and radio observations of auroral kilometric radiation (AKR) to infer the development of the auroral acceleration region. Observing these signatures with the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) and Wind spacecraft, we find evidence of auroral acceleration that allowed amplification of AKR to similar intensities as during super-Alfvénic coupling. This coincides with polar electron aurora around 8°square in latitude and at magnetic latitudes greater than 88°. The multipoint radio observations imply sources are generated along a constrained flux tube. Given the primary coincidence of AKR and the electron polar spot ∼3 hr following the incidence of minimally sub-Alfvénic (M A ∼ 0.4) solar wind at Earth, this acceleration occurs while the Alfvén wings are most complete. Given the IMF conditions, auroral morphology of the polar spot and the inference of an upward field-aligned current, the magnetospheric dynamics are most related to those of the high-latitude dayside aurora (HiLDA). These observations are the first to show AKR amplification from HiLDA and during a sub-Alfvénic magnetosphere, highlighting the possibility of strong localized coupling under quiet geomagnetic conditions.Plain Language Summary When the solar wind becomes sub-Alfvénic, the level of interaction with the terrestrial magnetosphere can be suppressed due to its structure becoming highly perturbed. Sub-Alfvénic solar wind is a rare occurrence, however; one of the longest duration sub-Alfvénic events occurred between 23 and 25 May 2002 and allowed enough time for the magnetosphere to change configuration. With observations of the aurora in ultraviolet (UV) and radio wavelengths (in the high latitude ionosphere and along co-located magnetic field lines, respectively) we find evidence of particle acceleration into the polar atmosphere during this event. This acceleration is highly constrained, producing localized electron aurora often centered on the magnetic pole. The solar wind conditions and the magnetospheric observations suggest the observed dynamics are related to known phenomena that occur during super-Alfvénic conditions, observed here for the first time during this abnormally quiet magnetospheric state and with associated radio emissions. These observations highlight the possibility of localized interactions that can be as intense as typical cases, even when conditions imply a quiet magnetosphere
Speciation of the Oxide Phase of Molybdenum‐Based HDS Catalysts Enhanced with Organic Additives Using an EXAFS/Raman Coupling Methodology
No full textInternational audienceThe ability to gain access to the speciation of hydrodesulfurization (HDS) catalysts used for removing sulfur and nitrogen from transportation fuels is becoming a key feature in the understanding and improvement of their catalytic activity with the aim of reducing greenhouse gas emissions of fossil fuels. A novel coupling methodology between Raman spectroscopy and X‐ray absorption spectroscopy (XAS) was developed, which allows for precise qualitative and quantitative analysis of the oxide phase of Mo‐based catalysts. This enabled the detailed study of various impregnation parameters and the characterization of HDS catalysts before sulfidation. To illustrate this methodology, the effects of two additives (triethylene glycol and citric acid) were studied. The results demonstrated that organic additives exert a profound influence on the speciation of oxide precursors of molybdenum‐based catalysts. The presence of these additives enhances the dispersion of Keggin or Dawson heteropolyanions (HPAs) on the support by maintaining a high phosphorus‐to‐molybdenum ratio in solution. This is achieved by two strategies: triethylene glycol (TEG) exhibits a pronounced affinity for alumina hydroxyls, while citric acid compensates for phosphate adsorption through the formation of a stable Mo‐citrate complex
Calculs de Le Verrier pour la découverte de Neptune analysés à partir de ses manuscrits
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Optimizing a cold plasma catheter for the local treatment of biliary tract cancer
No full textInternational audienceThis work consists in developing a cold atmospheric plasma (CAP) catheter designed to fit an endoscope and to demonstrate its safety to elicit local antitumor effects in cholangiocarcinoma, a cancer of the biliary tract. Such device relies on very constraining specifications to ensure electrical and thermal safety, both for patients and practitioners. In preclinical models mimicking human biliary tract, we demonstrate that our plasma catheter can safely operate in a confined environment (Ømax = 6 mm) in presence of a conductive liquid flow (bile). Exposure of a bile substitute to CAP leads to an increase in nitrite and hydrogen peroxide species (RONS). Presumably, these RONS induce an oxidative stress in cancer cells, leading to antitumor effects. These investigations constitute advances for endoscopic applications aimed at targeting cancer
Sensitivity of neutrino oscillations to the Earth's interior properties
No full textInternational audienceUnderstanding the Earth s internal structure remains a major challenge, as traditional geophysical methods face ambiguities in linking seismic observations to temperature, composition, or mass density variations. Atmospheric neutrinos offer a complementary probe: while traversing the Earth, they undergo flavor oscillations that depend on the local electron density, which reflects both mass density and composition
Decoding the molecular torus of NGC 1068: Insights into its structure and kinematics from high-resolution ALMA observations
No full textInternational audienceContext. Previous kinematic analysis of the pc-scale molecular torus in NGC 1068 have revealed a very complex and inhomogeneous system involving several physical components, such as non-circular motions, turbulence, high-velocity outflows, and possibly even counter-rotation. Aims. Our study aims to dissect the kinematics and morphology of the molecular gas within the near-nuclear region of NGC 1068 to understand the mechanisms in the central Active Galactic Nucleus (AGN) that might fuel it, and the impact of its energy output on the surrounding molecular gas. Methods. We present high angular and spectral resolution ALMA observations of the HCO + ( J = 4→3) and CO ( J = 3→2) molecular lines in the near-nuclear region of the prototype Seyfert 2 galaxy NGC 1068. The spatial resolution (1.1 pc) is almost two times better than that of previous studies examining the same molecular lines at the same transitions and is the highest resolution achievable with ALMA at these frequencies. Our analysis focuses on moment maps, position-velocity (PV) diagrams, and spectra obtained at the position of the nuclear continuum source, along with a simple kinematic model developed using the 3DBarolo software. Results. Our observations reveal significant asymmetry between the eastern and western sides of the nuclear disc in terms of morphology, velocity, and line intensity. The broad lines ( σ ∼90 km/s) seen in the inner 2 pc could be accounted for by either beam smearing or highly turbulent gas in this region. Outside this radius, the mean velocities drop to ±30 km/s, which cannot be explained by asymmetric drift. We find low velocity connections extending to 13 pc, suggesting interactions with larger scale structures. The CO/HCO + line ratio at the nucleus reported here are extremely low compared to values in the literature of the same galaxy at lower spatial resolutions. We find high-velocity redshifted clouds in absorption and emission at the nuclear position. Conclusions. The molecular environment near the nucleus of NGC 1068 is highly disturbed and asymmetric, marked by the presence of a high-velocity infalling cloud. High excitation temperatures, high molecular column densities, along with the unusually low CO/HCO + line ratio close to the nucleus seem to indicate intense interaction with AGN radiation. These findings underscore the complexity of AGN feeding mechanisms and the pivotal role of high-resolution studies in unravelling the physical processes at play near supermassive black holes
PHIBSS : Searching for Molecular Gas Outflows in Star-forming Galaxies at z = 0.5–2.6
No full textInternational audienceWe present an analysis of millimeter CO observations to search for and quantify signatures of molecular gas outflows. We exploit the large sample of 0.5 < z < 2.6 galaxies observed as part of the PHIBSS1/2 surveys with the IRAM Plateau de Bure interferometer, focusing on the 154 typical massive star-forming galaxies with CO detections (mainly CO(3–2), but including also CO(2–1) and CO(6–5)) at signal-to-noise ratio (SNR) > 1.5 and available properties (stellar mass, star formation rate or SFR, size) from ancillary data. None of the individual spectra exhibit a compelling signature of CO outflow emission, even at high SNR > 7. To search for fainter outflow signatures, we carry out an analysis of stacked spectra, including the full sample, as well as subsets, split in terms of stellar mass, redshift, inclination, offset in SFR from the main sequence, and active galactic nuclei activity. None of the physically motivated subsamples shows any outflow signature. We report a tentative detection in a subset statistically designed to maximize outflow signatures. We derive upper limits on molecular gas outflow rate and mass loading factors η based on our results and find η ≤ 2.2–35.4, depending on the subsample. Much deeper CO data and observations of alternative tracers are needed to decisively constrain the importance of the cold molecular gas component of outflows relative to other gas phases
A Compact Ion‐Electron Plasma Camera Spectrometer With an Instantaneous Hemispheric Field of View
No full textInternational audienceUsing additive manufacturing and a selective metalization technique, we have developed a compact ion/electron plasma camera based on the donut topology. With its instantaneous field of view of , it eliminates the need for electrostatic deflectors. This 17 cm diameter plasma camera has an energy range from a few eV to 22 keV, an energy resolution of and a geometric factor of per pixel, with 64 pixels corresponding to as many individual directions of observation. We have characterized its experimental response under an electron beam and compared it with numerical simulations. We have shown how carbon foils can be used as conversion layers to sequentially measure ions and electrons with a set of micro‐channel plates biased at a fixed voltage. This principle was tested under electron and ion beams