Letteratura scientifica selezionata sul tema "Gas stopping cell"

Single-cell tests and exhaust gas analyses were conducted to understand the reaction behavior of formic acid (HCOOH) and its effect on fuel cell performance, as specified in the hydrogen quality standard for fuel cell vehicles. HCOOH decreased the voltage with increasing concentration, but the effect was smaller than that of carbon monoxide and performance was recovered by stopping the HCOOH supply. Exhaust gas analysis during the fuel cell operation and electrochemical measurements with HCOOH adsorbed on the electrocatalyst showed that the HCOOH supplied to the anode should permeate the electrolyte membrane and be oxidized at the cathode to produce carbon dioxide. Verification tests in the hydrogen circulation system that is typically used in actual fuel cell vehicles confirmed that the effect of HCOOH did not appear at current densities up to 2.0 A cm−2 and concentrations up to 5 ppm.

Single-cell tests and exhaust gas analyses were conducted to understand the reaction behavior of formic acid (HCOOH) and its effect on fuel cell performance, as specified in the hydrogen quality standard for fuel cell vehicles. HCOOH decreased the voltage with increasing concentration, but the effect was smaller than that of carbon monoxide and performance was recovered by stopping the HCOOH supply. Exhaust gas analysis during the fuel cell operation and electrochemical measurements with HCOOH adsorbed on the electrocatalyst showed that the HCOOH supplied to the anode should permeate the electrolyte membrane and be oxidized at the cathode to produce carbon dioxide. Verification tests in the hydrogen circulation system that is typically used in actual fuel cell vehicles confirmed that the effect of HCOOH did not appear at current densities up to 2.0 A cm−2 and concentrations up to 5 ppm.

The inverse-kinematic thick-target method has been used in order to investigate 212Po alpha-structure by the elastic scattering of 208Pb on 4He target. A 208Pb beam, accelerated by the Superconducting Cyclotron (CS) of Laboratori Nazionali del Sud - INFN, at the incident energy of 10.1 A MeV was impinging onto a specifically designed 4He gas cell, two meter long. The gas cell wasacting both as target and as beam degrader, stopping the beam before reaching the alpha-particle detection system placed at 0° with respect to the beam axis. In order to disentangle the elastic contribution from other reaction channels (e.g. inelastic scattering) a microchannel plate was used to measure the Time of Flight(ToF) of both the 208Pb beam particles and the ejectiles along the gas cell. The 208Pbstopping power in the 4He gas target was also measured, as a key ingredient in order to establish theinteraction point inside the gas cell, in turn determining the solid angle covered by the detector. In the following, the experimental technique will be described, and the results of a preliminary data analysis will be shown.

Cette thèse présente une série de développements visant à réaliser la spectroscopie laser à ionisation résonante sur des isotopes à vie courte produits par le Spectromètre Super Séparateur (S³) et stoppés dans la cellule à gaz de sa branche basse énergie (S³-LEB). Cette recherche se concentre sur deux sujets. Tout d'abord, des mesures de spectroscopie laser hors ligne ont été réalisées sur des isotopes stables d'erbium, l'élément de choix pour la mise en service en ligne de S³-LEB. Ces mesures ont été réalisées en utilisant la configuration complète de S³-LEB ainsi que la gamme de systèmes laser Ti:sa disponibles, représentant une validation des principes de fonctionnement de l'ensemble de l'appareillage. Pour identifier le schéma optimal pour les prochaines expériences en ligne, différentes transitions atomiques ont été étudiées par spectroscopie laser dans la cellule à gaz et dans le jet de gaz. Les déplacements isotopiques ont été déterminés pour les étapes d'excitation et d'ionisation. Les facteurs de champ F et de masse M des étapes d'excitation ont été extraits du déplacement isotopique à l'aide d'une analyse King-plot, et les incertitudes expérimentales associées aux deux facteurs ont été discutées. Des mesures de la puissance de saturation ont été effectuées et les coefficients d'élargissement et de décalage des raies dus à la pression ont été déterminés dans l'environnement de la cellule à gaz. De plus, les coefficients hyperfins du premier état excité de la transition à 408,8 nm ont été extraits de la spectroscopie à jet gazeux à haute résolution avec une résolution spectrale d'environ 200 MHz. La transition à 408,8 nm de l'erbium est proposée comme une candidate appropriée pour les premières expériences sur S³. Deuxièmement, des simulations ont été réalisées afin de développer une future génération de cellule à gaz S³-LEB optimisée pour l'étude des isotopes à courte durée de vie, ceux-ci présentant un temps d'extraction réduit et utilisant un mécanisme de neutralisation universel. Dans cette cellule à gaz, l'extraction rapide des ions est obtenue grâce à une combinaison du champ électrique et du flux gazeux. Des simulations ont été réalisées avec des logiciels de pointe afin de souligner l'aspect pluri-disciplinaire, notamment l'écoulement du gaz, le champ électrostatique, le transport des ions sous haute pression et la dynamique des électrons générés par l'ionisation des gaz. Sur la base de ces simulations, un prototype optimisé de cellule à gaz a été conçu en prenant en compte le temps d'extraction, l'efficacité, ainsi que le temps de neutralisation
This thesis presents a series of developments aimed to perform resonance-ionization laser spectroscopy on short-lived isotopes produced by the Super Separator Spectrometer (S³) of SPIRAL2 at GANIL and stopped in the gas cell of its Low Energy Branch (S³-LEB). This research focuses on two topics. Firstly, off-line laser spectroscopy measurements were performed on stable isotopes of erbium, the element of choice for the on-line commissioning of S³-LEB. These measurements were performed using the full S³-LEB setup along with the range of available Ti:sa laser systems, representing a proof of principle of the entire apparatus. To identify the optimal scheme for the forthcoming on-line experiments, different atomic transitions were studied by laser spectroscopy in the gas cell and in the gas jet. Isotope shifts were determined for the excitation and ionization steps. Field and mass-shift factors for the excitation steps were extracted from the isotope-shift data using King-plot analysis, and the associated experimental uncertainties in the two factors were discussed. Saturation-power measurements were carried out and the pressure broadening and shift coefficients were determined in the gas-cell environment. Additionally, hyperfine coefficients for the first excited state of the 408.8 nm transition were extracted from the high-resolution gas-jet spectroscopy with a spectral resolution of around 200 MHz. The 408.8 nm transition of erbium is proposed as a suitable candidate for day-one experiments at S³. Secondly, simulations were performed to develop a future generation of the S³-LEB gas cell optimized for the study of short-lived isotopes, featuring a reduced extraction time and using a universal neutralization mechanism. In this gas cell, fast ion extraction is achieved through a combination of electrical field and gas flow. Simulations were performed with the state-of-the-art software for capturing the multiphysics aspect, including the gas flow, the electrostatic field, the ion transport in high pressure and the dynamics of electrons generated by the ionization of the gas. Based on these simulations, an optimized gas-cell prototype has been designed, taking into account the extraction time, the efficiency, as well as the time available for neutralization

Abstract Underground Hydrogen Storage (UHS) in aquifer reservoirs is pivotal for stabilizing the supply of renewable energy, addressing its inherent variability. As UHS technology evolves, the need for analyses that capture the complex interactions of hydrogen within subsurface environments becomes increasingly critical. To meet this requirement, we utilize the Eclipse 300 compositional simulator with the GASWAT option to generate high-fidelity datasets, which model the intricate gas-aqueous phase equilibria essential for understanding hydrogen behavior underground. These datasets, while fundamental, are supplemented by our Physics-regularized Fourier-Integrated Hybrid Deep Neural Framework (PR-F-IHDNF) to enhance predictive capabilities. This deep learning-based surrogate model integrates convolutional LSTM, convolutional neural networks, and Fourier neural operators, all regularized with the Hydrogen-Water Mass Balance Equation, to predict the evolution of pressure and hydrogen saturation over time during injection and production cycles. Our case study of the Fenton Creek field involved detailed reservoir modeling based on a grid of 97 × 18 × 35 cells, each measuring 121×136×2.8 ft. Although the entire grid was used to generate comprehensive simulation data, we concentrated on a sector grid of 44 × 11 × 11 cells for PR-F-IHDNF training to enhance computational efficiency. This sector, strategically centered around a key well, allowed us to accurately capture dynamic hydrogen behavior. Through Latin Hypercube sampling, we explored a range of reservoir properties and operational parameters, adapting our modeling techniques to the cyclical nature of hydrogen storage and retrieval. During the data generation phase, 76 simulations were completed within 48 hours. Each simulation or realization encompassed a 24-month cycle of hydrogen injection and production, initiating with 6 months of hydrogen cushion gas injection followed by alternating three-month cycles of production and injection. This sequence resulted in three complete cycles after the initial cushioning phase. PR-F-IHDNF was trained using 26 simulation realizations and validated with 15 realizations to monitor training performance and prevent overfitting. Additionally, 35 simulation realizations were used to test the trained PR-F-IHDNF, ensuring its generalization capabilities. Results from deploying the PR-F-IHDNF showed high precision, achieving an accuracy of 99.7% for pressure and 97% for hydrogen saturation across 35 test realizations—more than the 26 used in training—to robustly verify its generalization capabilities. This outcome underscores the efficacy of incorporating the Hydrogen-Water Mass Balance Equation for regularization. The mean absolute error was recorded at 10.54 psi for pressure and 0.0018 for hydrogen saturation, indicating good predictive reliability. Although training the PR-F-IHDNF required significant computational resources, with a training duration of 36 hours and early stopping implemented at 271 epochs of the planned 300, it efficiently predicts outcomes for any simulation case in less than 0.8 seconds, showcasing its practicality for real-time applications. The PR-F-IHDNF model can predict complex underground processes, making it useful for testing different scenarios and improving storage strategies. It helps identify important factors and refine operations, supporting better decisions for managing underground hydrogen storage.