Comparison of Pressure Driven Electrolytic Membranes (PDEM) and Solid Electrolyte Oxygen Pumps (SEOP) for Small Scale Oxygen Production

AbstractThis work evaluates the thermodynamic performances of two oxygen separation technologies, Pressure Driven Electrolytic Membranes (PDEM) and Solid Electrolyte Oxygen Pumps (SEOP), focusing on the application to small scale oxygen production. We show that PDEM systems operated with a specific flux of 5 liters of oxygen per minute per square meter of active membrane surface (5 LO2/min-m2) can reach an energy consumption as low as 0.39 kWh/kgO2. In the same conditions with a SEOP, the optimized energy consumptions are 0.52 and 0.49 kWh/kgO2 respectively for atmospheric and pressurized configurations

Digital quantum simulators in a scalable architecture of hybrid spin-photon qubits

Resolving quantum many-body problems represents one of the greatest challenges in physics and physical chemistry, due to the prohibitively large computational resources that would be required by using classical computers. A solution has been foreseen by directly simulating the time evolution through sequences of quantum gates applied to arrays of qubits, i.e. by implementing a digital quantum simulator. Superconducting circuits and resonators are emerging as an extremely-promising platform for quantum computation architectures, but a digital quantum simulator proposal that is straightforwardly scalable, universal, and realizable with state-of-the-art technology is presently lacking. Here we propose a viable scheme to implement a universal quantum simulator with hybrid spin-photon qubits in an array of superconducting resonators, which is intrinsically scalable and allows for local control. As representative examples we consider the transverse-field Ising model, a spin-1 Hamiltonian, and the two-dimensional Hubbard model; for these, we numerically simulate the scheme by including the main sources of decoherence. In addition, we show how to circumvent the potentially harmful effects of inhomogeneous broadening of the spin systems

Simulated Versus Monitored Building Behaviours: Sample Demo Applications of a Perfomance Gap Detection Tool in a Northern Italian Climate

Green building technologies and design-correlated choices may significantly contribute to supporting the transition toward net energy flows in the built environment. Nevertheless, large discrepancies are underlined between standard simulated and monitored building behaviours requiring approaches able to simply correlate real building behaviours and simulated ones to further support coherent certification and/or optimization. The paper focusses on the application of a semi-automatic methodology to compare and evaluate thermal behaviours of buildings considering monitored and simulated data. The approach is based on a new Python tool developed by the authors, able to manage EnergyPlus inputs and perform multi-source KPIs calculations. The mentioned tool is used here to support semi-automatic model verifications of real weather data by optimizing model parameters to fit monitored behaviours. The approach is applied in this chapter to two demo buildings, a municipality school and a residential unit, located in the Turin metropolitan area of Piedmont, in Northwest Italy

Thermal Comfort and Climatic Potential of Ventilative Cooling in Italian Climates

The chapter describes several climate-correlated variables and suitable key performance indicators (KPIs) to define the local ventilative cooling potential. Furthermore, a methodology is presented to verify potential correlations between climate KPIs and indoor comfort parameters. The latter values are calculated by adopting dynamic energy simulations (EnergyPlus) and comfort models – both Fanger (ISO 7730) and the recently updated EU adaptive comfort approach (EN 16798-1) – considering a sample building unit. Simulations are run by using a parametric-enabling tool developed by the research unit to check correlations and is part of work performed for the PRELUDE project, co-funded by the EU, Horizon 2020 research and innovation programme under grant agreement No 958345. The approach is applied to the whole Italian territory considering typical yearly (hourly defined) meteorological conditions for all municipalities (about 8000 data points). Strong connections between climate and building KPIs are underlined together with the high potential of ventilative cooling in reducing discomfort and energy needs in the Italian territory

W gamma production in hadronic collisions using the POWHEG+MiNLO method

We detail a calculation of W gamma production in hadronic collision, at Next-to-Leading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO program MCFM, which treats the fragmentation contribution in terms of photon fragmentation functions. We also perform comparisons to available LHC data at 7 TeV, for which we observe good agreement, and provide phenomenological results for physics studies of the W gamma production process at the Run II of the LHC. The new tool, which includes W leptonic decays and the contribution of anomalous gauge couplings, allows a fully exclusive, hadron-level description of the W gamma process, and is publicly available at the repository of the POWHEG BOX. Our approach can be easily adapted to deal with other relevant isolated photon production processes in hadronic collisions.Comment: 38 pages, 5 Tables, 9 Figures. Final version published in JHEP. Acknowledgments to Galileo Galilei Institute for Theoretical Physics and to INFN adde

Adoardo di Corbie e i lettori del de legibus in età carolingia

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Simulation of Oxygen Transport Membranes for CPO Reactors in Small-scale Hydrogen or Syngas Production Applications

The proposed work aims at presenting a 1D finite volume steady state simulation model of an Oxygen Transport Membrane for Catalytic Partial Oxidation (OTM-CPO) reactor developed at the Group of Energy COnversion Systems (GECOS) at Politecnico di Milano. The model is able to simulate supported and unsupported perovskite-based reactive membranes by means of a lumped mass and energy transport method; the active ceramic layer is modelled throughout a generalised O2permeation equation, which depends on the micro-structure characteristics and mixed-ion conduction properties of the material. The supporting porous structure is represented by a mass diffusion model dominated by gas-gas, porous and surface exchange transport processes. The model also includes a global chemical reaction kinetic mechanism of CPO on Rh-based catalysts. The model is applied to simulate the behaviour of a membrane reactor operated upstream the Hydrogen Transport Membrane for Methane Steam Reforming (HTM-MSR) installed at the Laboratory of Micro-Cogeneration (LMC) at Politecnico di Milano. The test bench is focused on testing fuel pre-processing systems for low temperature fuel cells (PEM) applications. The simulation object of this work would allow obtaining a feasibility assessment of the system and a preliminary design of the OTM-CPO reactor

Vapour - Liquid Equilibrium measurements of CO2 based mixtures: Experimental apparatus and testing procedures

At present, the accurate evaluation of the thermo-physical behaviour of multicomponent fluids represents a crucial element for studying and simulating low CO2 emission energy conversion technologies. In order to extend the range of application of the available thermodynamic models, an intense experimental research activity has been performed in recent years. The main purpose of this paper is to describe the experimental and modelling procedures applied by the authors to measure and to analyse data extracted from the Vapour-Liquid Equilibrium apparatus recently installed at LEAP laboratory. This test rig allows the characterization of mixture phase equilibrium properties on the basis of the static-analytical method, within the pressure and temperature ranges of 0-20 MPa and -60-200°C. Finally, the paper reports the most relevant features and the main guidelines for the instruments calibration procedures. © 2013 The Authors

Single Metal Atoms on Oxide Surfaces: Assessing the Chemical Bond through 17O Electron Paramagnetic Resonance

[Image: see text] Even in the gas phase single atoms possess catalytic properties, which can be crucially enhanced and modulated by the chemical interaction with a solid support. This effect, known as electronic metal–support interaction, encompasses charge transfer, orbital overlap, coordination structure, etc., in other words, all the crucial features of the chemical bond. These very features are the object of this Account, with specific reference to open-shell (paramagnetic) single metal atoms or ions on oxide supports. Such atomically dispersed species are part of the emerging class of heterogeneous catalysts known as single-atom catalysts (SACs). In these materials, atomic dispersion ensures maximum atom utilization and uniform active sites, whereby the nature of the chemical interaction between the metal and the oxide surface modulates the catalytic activity of the metal active site by tuning the energy of the frontier orbitals. A comprehensive set of examples includes fourth period metal atoms and ions in zeolites on insulating (e.g., MgO) or reducible (e.g., TiO(2)) oxides and are among the most relevant catalysts for a wealth of key processes of industrial and environmental relevance, from the abatement of NO(x) to the selective oxidation of hydrocarbons and the conversion of methane to methanol. There exist several spectroscopic techniques able to inform on the geometric and electronic structure of isolated single metal ion sites, but either they yield information averaged over the bulk or they lack description of the intimate features of chemical bonding, which include covalency, ionicity, electron and spin delocalization. All of these can be recovered at once by measuring the magnetic interactions between open-shell metals and the surrounding nuclei with Electron Paramagnetic Resonance (EPR) spectroscopy. In the case of oxides, this entails the synthesis of (17)O isotopically enriched materials. We have established (17)O EPR as a unique source of information about the local binding environment around oxygen of magnetic atoms or ions on different oxidic supports to rationalize structure–property relationships. Here, we will describe strategies for (17)O surface enrichments and approaches to monitor the state of charge and spin delocalization of atoms or ions from K to Zn dispersed on oxide surfaces characterized by different chemical properties (i.e., basicity or reducibility). Emphasis is placed on chemical insight at the atomic-scale level achieved by (17)O EPR, which is a crucial step in understanding the structure–property relationships of single metal atom catalysts and in enabling efficient design of future materials for a range of end uses

Integration of chemical looping combustion for cost-effective CO2 capture from state-of-the-art natural gas combined cycles

Chemical looping combustion (CLC) is a promising method for power production with integrated CO2 capture with almost no direct energy penalty. When integrated into a natural gas combined cycle (NGCC) plant, however, CLC imposes a large indirect energy penalty because the maximum achievable reactor temperature is far below the firing temperature of state-of-the-art gas turbines. This study presents a techno-economic assessment of a CLC plant that circumvents this limitation via an added combustor after the CLC reactors. Without the added combustor, the energy penalty amounts to 11.4%-points, causing a high CO2 avoidance cost of $117.3/ton, which is more expensive than a conventional NGCC plant with post-combustion capture ($93.8/ton) with an energy penalty of 8.1%-points. This conventional CLC plant would also require a custom gas turbine. With an added combustor fired by natural gas, a standard gas turbine can be deployed, and CO2 avoidance costs are reduced to $60.3/ton, mainly due to a reduction in the energy penalty to only 1.4$96.3/ton when a hydrogen cost of $15.5/GJ is assumed. Advanced heat integration could reduce the CO2 avoidance cost to$90.3/ton by lowering the energy penalty to only 0.6%-points. An attractive alternative is, therefore, to construct the plant for added firing with natural gas and retrofit the added combustor for hydrogen firing when CO2 prices reach very high levels