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Abstract Energy geostructures (EGs) represent an innovative technology in the sustainable energy agenda and are useful for satisfying the energy needs of the built environment. They are usually involving geostructures such as piles, walls, tunnels, shafts, and sewers. The application of such technology to infrastructure projects may have considerable thermal potential because of the large surfaces that can be thermally activated. This study focuses on thermo-active walls (energy walls, EWs), which are retaining structures used to sustain the sides of excavations. Key features related to their thermal design are examined, and a design methodology is proposed. The heat-exchange modes involving EWs and the surrounding materials (concrete, soil, air) are investigated via extensive three-dimensional hydrothermal finite-element simulations involving the non-isothermal flow in the heat exchangers (HEs), as well as all other heat-exchange modes. The results are first presented as charts related to the thermal behavior of the HEs under different hydrothermal environments. Finally, a methodology for early-stage thermal performance design is proposed, and a corresponding flowchart is presented. This study may be helpful for incorporating EGs into the engineering design.

Integrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering. JPhys Photonics, 4 (1) ISSN:2515-7647

International audience; A wide range of gas mixtures is used for the operation of different gaseous detectors for particle physics research. Among them are greenhouse gases like C$_2$H$_2$F$_4$ (R134a), CF$_4$ (R14), C$_4$F$_{10}$ (R610) and SF$_6$, which are used because they allow to achieve specific detector performance that are necessary for data taking at the LHC experiments (i.e. stability, long term performance, time resolution, rate capability, etc.). Such gases are currently subject to a phase down policy that started to affect the market with price increase and, in the long term, may cause a decrease in their availability. Four different strategies have been identified to optimize the gas usage. As immediate actions, during the LHC Long Shutdown 2 the gas systems will be upgraded to cope with new detector requirements and, in parallel, extensive campaigns for fixing leaks at detector level will be performed. The development of gas recuperation plants is going to be the next step. They aim in extracting greenhouse gases from the exhaust of gas recirculation systems allowing further re-use. Several plants of this type are already in use at the CERN LHC experiments. Recent developments are concerning systems for CF$_4$ and R134a recuperation. Recently two systems for CF$_4$ were developed allowing to reduce the consumption by about 50\%. The R134a recuperation plant is still in a R\&D phase; however, encouraging results have been obtained. For future long-term detector operation, R\&D studies are ongoing for finding $green$ alternatives to the currently used gases. The last strategy consists in using industrially developed plants for the disposal of greenhouse gases by decomposition in harmless compounds. This solution avoids the emission in the atmosphere but it is not optimizing the gas usage. Moreover, problems like gas availability and price are not addressed and they might become the challenge in the years to come due to the greenhouse phase down policy.

The propagation of uncertainties in reaction cross sections and rates of neutron-, proton-, and $\alpha$-induced reactions into the final isotopic abundances obtained in nucleosynthesis models is an important issue in studies of nucleosynthesis and Galactic Chemical Evolution. We developed a Monte Carlo method to allow large-scale postprocessing studies of the impact of nuclear uncertainties on nucleosynthesis. Temperature-dependent rate uncertainties combining realistic experimental and theoretical uncertainties are used. The importance of contributions of cross sections of reactions on excited states of the nuclear targets, which have weights different from from the thermal Boltzmann population factors, is explained. From detailed statistical analyses of the Monte Carlo data uncertainties in the final abundances are derived as probability density distributions. Furthermore, based on rate and abundance correlations an automated procedure identifies the most important reactions in complex flow patterns from superposition of many zones or tracers. The method already has been applied to a number of nucleosynthesis processes. Comment: 6 pages, 1 figure; Proceedings of the 27th International Nuclear Physics Conference, Glasgow, UK, 2019; to appear in J. Phys. Conf. Proc; v2: reference added, typos fixed

The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely unknown. Rotational-induced mixing in the stellar interior can impact the nucleosynthesis during the stellar life of massive stars and lead to stellar ejecta having various chemical compositions. We present low and zero-metallicity 20, 25 and 40 $M_{\odot}$ stellar models with various initial rotation rates and assumptions for the nuclear reactions rates. With increasing initial rotation, the yields of light (from $\sim$ C to Al) and trans-iron elements are boosted. The trans-iron elements (especially elements heavier than Ba) are significantly affected by the nuclear reaction uncertainties. The chemical composition of the observed CEMP (carbon-enhanced metal-poor) stars CS29528-028 and HE0336+0113 are consistent with the chemical composition of the material ejected by a fast rotating 40~$M_{\odot}$ model. Comment: Proceeding of the Nuclear Physics in Astrophysics IX conference, to appear in the Journal of Physics: Conference Series

Uranus and Neptune, and their diverse satellite and ring systems, represent the least explored environments of our Solar System, and yet may provide the archetype for the most common outcome of planetary formation throughout our galaxy. Ice Giants will be the last remaining class of Solar System planet to have a dedicated orbital explorer, and international efforts are under way to realise such an ambitious mission in the coming decades. In 2019, the European Space Agency released a call for scientific themes for its strategic science planning process for the 2030s and 2040s, known as Voyage 2050. We used this opportunity to review our present-day knowledge of the Uranus and Neptune systems, producing a revised and updated set of scientific questions and motivations for their exploration. This review article describes how such a mission could explore their origins, ice-rich interiors, dynamic atmospheres, unique magnetospheres, and myriad icy satellites, to address questions at the heart of modern planetary science. These two worlds are superb examples of how planets with shared origins can exhibit remarkably different evolutionary paths: Neptune as the archetype for Ice Giants, whereas Uranus may be atypical. Exploring Uranus' natural satellites and Neptune's captured moon Triton could reveal how Ocean Worlds form and remain active, redefining the extent of the habitable zone in our Solar System. For these reasons and more, we advocate that an Ice Giant System explorer should become a strategic cornerstone mission within ESA's Voyage 2050 programme, in partnership with international collaborators, and targeting launch opportunities in the early 2030s. Comment: 34 pages, 9 figures, accepted to Planetary and Space Science