Geometry Of System Research Articles

Electron Quantum Optics with Beam Splitters and Waveguides in Dirac Matter

AbstractAn electron is a quantum particle and behaves as both a particle and a probability wave. On account of this it can be controlled in a similar way to a photon and electronic devices can be designed in analogy to those based on light when there is minimal excitation of the underlying Fermi sea. Here, splitting of the electron wavefunction is explored for systems supporting Dirac type physics, with a focus on graphene but being equally applicable to electronic states in topological insulators, liquid helium, and other systems described relativistically. Electron beam‐splitters and superfocusers are analysed along with propagation through nanoribbons, demonstrating that the waveform, system geometry, and energies all need to balance to maximise the probability density and hence lifetime of the flying electron. These findings form the basis for novel quantum electron optics.

Object classification through unseen scatters with a physical model trained neural network

Deep learning (DL) has been extensively employed to imaging or classify objects through scattering media. However, the performance of a trained network degrades dramatically when it is tested at scattering conditions statistically differing from those in the training. Therefore, how to retain DL’s generalization capacity is still a challenging task, with imaging or classification through untrained (unseen) scatters is highly desired. Here, we introduce physical model approach for network training, which enables generalization capability via learning from sufficiently large amount of model-based synthetic speckles. By mimicking the point spread function (PSF) of an incoherent scattering system, and diversifying the scattering realizations with random phasers, a generalized neural network is obtained. Object classification through unseen scatters is experimentally demonstrated. The random phasers prohibit DL from converging to a specific training medium, which is crucial to the creation of a generalized neural network. Unlike traditional data-driven DL that has nearly zero predicting accuracy, our model-trained network is generalized and being able to classify objects through untrained scattering media with accuracy as high as 60%. Neither the experimental scenes nor system geometry is required in creating the synthetic speckles, our method represents a genuine approach in data generation for DL training, paving the way to a highly generalized neural network for inverse scattering problems.

Optimum Geometry of Steel Diagrid Structural System to Resist Progressive Collapse

Optimum Geometry of Steel Diagrid Structural System to Resist Progressive Collapse

Transmission of a position-dependent mass system through a soft Coulomb potential

This research delves into the fascinating transmission characteristics of a system with variable mass, confined by a Coulomb-like potential. By utilizing an analytic approach to transmission probability, we were able to unveil the intriguing features that are observed experimentally in a specially designed two-dimensional lattice. This lattice was engineered to manipulate itinerant electrons through entanglement, resulting in variable masses as they traverse the lattice. To build our model system, we utilized the displacement operator approach to the position-dependent effective mass theory. This allowed us to investigate the effects of different configurations of leads, system geometries and lattice deformations on the transmission characteristics of the system. The resulting data showed that the model system was highly sensitive to these parameters, which led to various interesting features. First, we observed Andreev-like reflections, which occur when a particle is reflected as a hole, resulting in the transfer of both energy and charge. Another feature was reflectionless transmission, in which the transmission probability of a particle is close to unity, and almost no reflection occurs. We also observed complete localization of charge carriers, where the transmission probability is effectively zero, indicating that the charge carriers are completely confined within the lattice. Our findings demonstrate the remarkable versatility of the effective mass approach in the modeling of physical systems. By unraveling the intricate relationships between system parameters and transmission probability, we have gained new insights into the behavior of itinerant charge carriers in lattice structures. These insights may guide the design and development of novel electronic devices with enhanced performance and functionality.

The effects of differential shortening and competent blocks on the structural development of Andean fold-and-thrust belts at 32°-34°S: Insights from analogue models

Andean fold-and-thrust belts (FTBs) in the western border of South America show important along-strike variations in their structural style (thin- or thick-skinned) and shortening magnitudes, among others. These variations can arise from multiple factors, such as depth-to-detachment, geometry, and thickness of underlying basins, structural highs, the competence of the units involved in deformation, pre-orogenic structure of the basement, the rheological state of the upper crust or latitudinal gradients in shortening, among others. We carry out a set of new analogue models to understand how two of these factors affect the development and the geometry of the thrust systems within the Andean Principal Cordillera and adjacent fold-and-thrust belts at 32°-34°S (La Ramada and Aconcagua FTBs). In this contribution, we present the results of analogue modeling of doubly-vergent thrust systems with a built-in heterogeneity that allow us to evaluate the influence of differential shortening and presence of competent blocks (of relatively higher cohesion) in the generation, evolution, and structural setting of Andean FTBs. We highlight that despite the similar pattern of differential shortening in the models, the presence of the competent block has a significant influence on the structural configuration and leads to greater topographic uplift. Differential shortening plays a role in accommodating deformation, but when a competent block is present, the faults bounding the block control the deformation, producing a notable curvature of the FTBs. Summarizing, the presence of a competent block significantly influences the structural configuration within a doubly-vergent thrust system, emphasizing the role of inherited architecture in the orogenic growth of the Southern Central Andes.

Characteristics and controls of an offshore freshened groundwater system in the Shengsi region, East China Sea

Offshore freshened groundwater (OFG) has been encountered in continental margins around the world and identified as a potential unconventional water resource. In China, coastal areas and islands face limited freshwater resources. The East China Sea, specifically the region north of Shengsi islands, may contain an OFG system hosted in buried paleochannels associated with the ancient Yangtze river. To assess the OFG potential, characteristics, and controls in this region, we employed an integrated modeling approach. We constructed a 2D geological model of Quaternary sediments based on data from two well sites. By considering sea-level fluctuations over the past 200,000 years, we conducted a paleo-reconstruction of groundwater flow and solute transport conditions on the 2D transect. We compared the simulated present-day distribution of OFG in the model with borehole observations. Our findings indicate that the region was mostly sub-aerially exposed during the simulated period, allowing for potential meteoric recharge. Numerical results demonstrate a high likelihood of a laterally extensive OFG system existing today. The mechanism responsible for its formation appears to be meteoric recharge and offshore directed groundwater flow caused by increased hydraulic gradients during sea-level lowstand. The model suggests that the OFG system forms an oceanward dipping wedge, with the top occurring approximately 50–100 m below the seafloor. Freshwater is likely present down to the basement at around 250 m. The geometry and volume of the OFG system are strongly influenced by the shelf stratigraphy. We estimate the volume of freshwater in the region to range from 0.5 to 1.6 km3 km-1, indicating a viable potential freshwater resource for the Shengsi region and coastal city of Shanghai. To gain further insights, we recommend conducting additional investigations using geophysical techniques.

Application of artificial neural networks for predicting the bearing capacity of the tip of a pile embedded in a rock mass

Addressing the problem of the bearing capacity of the tip of a pile in rock needs to consider a full-nonlinear behavior of the rock, as the Hoek and Brown failure criterion, and including the various geometric parameters defining the system geometry. It usually needs the use of complex numerical models. They require a high level of training and expertise and are commonly out of the reach of engineers on the day-to-day calculation procedures. Technical codes usually recommend simpler formulae based on one or two rock parameters, their accuracy relying on particular and local empirical testing. This research develops an artificial neural network (ANN) that solves the previous difficulties. The ANN is based on a group of 1440 calculations using the novel numerical procedure Discontinuity Layout Optimization (DLO). This numerical method can efficiently reproduce the non-linear behavior of the rock (including rock type, uniaxial compressive strength, and geological strength index) for every configuration of the model (foundation width, pile embedment, and height of the overlying soil). Once the ANN is trained and optimized, it can easily predict any result within its range of applicability. Furthermore, it can be reduced to a simple set of recursive equations to be implemented in a spreadsheet. The proposed ANN has only one hidden layer besides the input and output layers, with (6)-(8)-(1) neurons, respectively. It gives highly accurate results with minimum cost and can be a useful tool for engineers and scientists in the foundation field.

Determination of the electron temperature in a supersonic jet of a gas-discharge source from current measurements by an insulated probe system

The aim of this work is to substantiate the possibility of using the classical procedure for determining the electron temperature for diagnosing a supersonic jet of a collisionless plasma of a diatomic gas using the current-voltage characteristic of an insulated probe system. The probe system consists of a cylindrical probe and a reference electrode composed of several cylinders, all placed transversely in the plasma flow. The ratio of the current-collecting surface area of the reference electrode to the area of the probe is arbitrary and can be significantly less than required by the theory of a single probe. Based on a previously constructed mathematical model of current collection, which includes the calculation of the equilibrium potential of the reference electrode as a function of the probe bias voltage, a procedure is developed for determining the electron temperature by measuring the probe currents in a jet of a gas-discharge source of a laboratory dissociated plasma. An approximation of the floating potential of the insulated probe system in a strongly nonequilibrium plasma of a gas-discharge source jet is found, which allows one to determine the boundaries of the transition region of the current-voltage characteristic using a priori information on the plasma parameters. A formula is obtained for extrapolating the ion probe current vs. bias potential relationship into the transition region of the current-voltage characteristic. Within the framework of the adopted mathematical model of charged plasma particle collection, a numerical analysis of the method error of the electron temperature determination procedure is performed. Quantitative characteristics of the effect of the insulated probe system geometry on the method error are obtained. A numerical simulation of the effect of the probe current measurement errors showed that, within the framework of the adopted model, the accuracy of determining the electron temperature using the insulated probe system is comparable with the accuracy of measurements with a single cylindrical probe. The results obtained may be used in the diagnostics of a laboratory plasma of a gas-discharge source.

Outdoor experimental validation for ultra-high concentrator photovoltaic with serpentine-based cooling system

With demand for renewable energy growing, concentrator photovoltaic thermal hybrids have great potential. Maximising concentration ratios through the deployment of multi-stage optics can yield high power outputs from multi-junction solar cells. To prevent damaging thermal stress and to enable extraction of thermal energy, a capable cooling system is necessary.The primary objective of this study is to maximise the effective concentration ratio over a solar cell and calibrate the system to optimise the energetic and exergetic efficiencies. The capability of the serpentine-based cooling system is investigated for each concentrator optic configuration. Originality is found in the presentation of the 3-stage optic, and the use of outdoor real-world experimental data to validate a computational model. This model uses both ray tracing, heat and mass transfer simulations to enhance the understanding of system operation and enable accurate prediction of performance under various conditions. Results show focal spot shape is more important than raw optical efficiency for electrical output, making the 3-stage optic superior to the other configurations in most regards. An effective concentration of over 1200 × is achieved. Higher exergetic efficiencies are consistently found in the double serpentine configuration, though variation does not exceed ±0.3% when only changing cooling system geometry.

Double Reservoirs Imaged Below Great Sitkin Volcano, Alaska, Explain the Migration of Volcanic Seismicity

AbstractVolcanic seismicity provides essential insights into the behavior of an active volcano across multiple time scales. However, to understand how magma moves as the eruption cycle develops, better knowledge of the geometry and physical properties of the magma plumbing system is required. In this study, using full‐wave ambient noise tomography, we image the three‐dimensional (3‐D) crustal shear‐wave velocity structure below Great Sitkin Volcano in the central Aleutian Arc. The velocity model reveals two low‐velocity anomalies correlating with the migration of volcanic seismicity. With a bulk melt fraction of about 2.5%–9%, these low‐velocity anomalies are interpreted as mushy magma reservoirs. We propose a six‐stage eruption cycle to explain the migration of seismicity and the alternating eruption of the two reservoirs with different recharging histories. These findings have broad implications for the dynamics of magma plumbing systems and the structural control of eruption behaviors.

Prominence detection and chromosphere feature on the prototype RS CVn of active binary systems

ABSTRACT We present a study of high-resolution spectra of RS Canum Venaticorum (RS CVn), a prototype of active binary systems. Our data were obtained from 1998 to 2017 using different telescopes. We analyse the chromospheric activity indicators $\rm{Ca~{\small II}}$ IRT, Hα, $\rm{Na~{\small I}}$ D1, D2 doublet, $\rm{He~{\small I}}$ D3, and Hβ using a spectral subtraction technique. The chromospheric emission stems mainly from the K2 IV primary star, while the F5 V secondary star only shows weak emission features in a few of our spectra. We find excess absorption features in the subtracted Hα lines and other activity indicators from spectra taken near primary eclipse, which we ascribe to prominence-like material associated with the primary star. We estimate size limits of these tentative prominences based on the geometry of the binary system, and investigate the physical properties of the strongest prominence. An optical flare, characterized by $\rm{He~{\small I}}$ D3 line emission, together with stronger emission in other activity lines, was detected. The flare energy is roughly comparable to strong flares observed on other RS CVn-type stars. The chromospherically active longitudes of RS CVn most frequently appear near the two quadratures of the system and display changes between observing runs, which indicates an ongoing evolution of its active regions.

Cone-beam CT sampling incompleteness: analytical and empirical studies of emerging systems and source-detector orbits.

Motivated by emerging cone-beam computed tomography (CBCT) systems and scan orbits, we aim to quantitatively assess the completeness of data for 3D image reconstruction-in turn, related to "cone-beam artifacts." Fundamental principles of cone-beam sampling incompleteness are considered with respect to an analytical figure-of-merit [FOM, denoted ] and related to an empirical FOM (denoted ) for measurement of cone-beam artifact magnitude in a test phantom. A previously proposed analytical FOM [, defined as the minimum angle between a point in the 3D image reconstruction and the x-ray source over the scan orbit] was analyzed for a variety of CBCT geometries. A physical test phantom was configured with parallel disk pairs (perpendicular to the -axis) at various locations throughout the field of view, quantifying cone-beam artifact magnitude in terms of (the relative signal modulation between the disks). Two CBCT systems were considered: an interventional C-arm (Cios Spin 3D; Siemens Healthineers, Forcheim Germany) and a musculoskeletal extremity scanner; Onsight3D, Carestream Health, Rochester, United States)]. Simulations and physical experiments were conducted for various source-detector orbits: (a)a conventional 360deg circular orbit, (b)tilted and untilted semi-circular (196deg) orbits, (c)multi-source (three x-ray sources distributed along the axis) semi-circular orbits, and (d)a non-circular (sine-on-sphere, SoS) orbit. The incompleteness of sampling [] and magnitude of cone-beam artifacts () were evaluated for each system and orbit. The results show visually and quantitatively the effect of system geometry and scan orbit on cone-beam sampling effects, demonstrating the relationship between analytical and empirical . Advanced source-detector orbits (e.g., three-source and SoS orbits) exhibited superior sampling completeness as quantified by both the analytical and the empirical FOMs. The test phantom and metric were sensitive to variations in CBCT system geometry and scan orbit and provided a surrogate measure of underlying sampling completeness. For a given system geometry and source-detector orbit, cone-beam sampling completeness can be quantified analytically (in terms arising from Tuy's condition) and/or empirically (using a test phantom for quantification of cone-beam artifacts). Such analysis provides theoretical and practical insight on sampling effects and the completeness of data for emerging CBCT systems and scan trajectories.

Deep and shallow crustal structure control on the late-stage volcanism in Syria Planum (Mars)

Long-lasting widespread volcanism in Mars is testified by the Tharsis volcanic province, one of the largest volcanic provinces with the largest shield volcanoes of the Solar System. However, volcanism on Mars is characterized also by the occurrence of broad volcanic fields, either in the form of small lava shields or monogenic volcanic cones. The region of Syria Planum (SP) is located east of the Tharsis province and between Noctis Labyrinthus to the North and Claritas Fossae to the southwest. It is an example of diffuse volcanism, presenting hundreds of small edifices (namely Syria Colles) which occur on top of a large bulge roughly 300 km × 200 km in size. SP exhibits a complex magmatic and volcano-tectonic evolution spanning from the early-Noachian to the more recent Amazonian. In this work, we investigate the geometry of the plumbing system of the SP volcanic field as well as the geometries of the volcanic constructs (i.e., vent elongation and vent alignment) that may be linked to the structures that fed the magma presenting a possible tectonic and volcanic evolution of the distributed volcanism phase in this area. The spatial distribution of vents and the overall map view shape of the volcanic field were studied in terms of vent clustering and spatial distribution. We show that the widespread and diffuse volcanism in SP presents clear vent clusters that are related to a deep source magma reservoir located at ∼100 km depth. We also show that Syria Colles vent elongations and azimuth distributions suggest that the magma exploited the inherited regional structural framework, coherent with the Syria Colles late-stage Amazonian magmatic event, and highlighting the role of a shallow crustal tectonic framework in shaping the Martian volcanism.

Mathematical Geometry and Groups for Low-Symmetry Metal Complex Systems.

Since chemistry, materials science, and crystallography deal with three-dimensional structures, they use mathematics such as geometry and symmetry. In recent years, the application of topology and mathematics to material design has yielded remarkable results. It can also be seen that differential geometry has been applied to various fields of chemistry for a relatively long time. There is also the possibility of using new mathematics, such as the crystal structure database, which represents big data, for computational chemistry (Hirshfeld surface analysis). On the other hand, group theory (space group and point group) is useful for crystal structures, including determining their electronic properties and the symmetries of molecules with relatively high symmetry. However, these strengths are not exhibited in the low-symmetry molecules that are actually handled. A new use of mathematics for chemical research is required that is suitable for the age when computational chemistry and artificial intelligence can be used.

Hypocenter‐Based 3D Imaging of Active Faults: Method and Applications in the Southwestern Swiss Alps

AbstractDespite the fact that earthquake occurrence can be strongly influenced by the architecture of pre‐existing faults, it remains challenging to obtain information about the detailed subsurface geometries of active fault systems. Current geophysical methods for studying such systems often fail to resolve geometrical complexities at sufficiently high spatial resolutions. In this work, we present a novel method for imaging the detailed 3D architectures of seismically active faults based on high‐precision hypocenter catalogs, using nearest neighbor learning and principal component analysis. The proposed approach enables to assess variations in fault instabilities and kinematics. We apply the method to the relatively relocated St. Léonard (max.ML = 3.2) and Anzère (max.ML = 3.3) microearthquake sequences in the Southwestern Swiss Alps, revealing strike‐slip fault systems with interconnecting stepovers at depths of 3–7 km and lengths ranging from 0.5 to 2 km. In combination with additional information about fault instabilities and kinematics, we observe significantly reduced earthquake migration velocities and fault locking processes within the stepovers. Understanding such processes and their role in the propagation of strain across stepovers is of great relevance, as these structures can potentially limit earthquake ruptures but also represent possible locations for the nucleation of larger ruptures. Our proposed method is expected to be broadly useful for further applications such as monitoring hydraulic fracture stimulations or geothermal exploration of natural, fluid‐bearing faults. Conducting similar high‐resolution spatiotemporal analyses of microseismic sequences has the potential to greatly enhance our comprehension of how the 3D fault architecture impacts seismogenic fault reactivation.

Effect of cartilaginous rings in tracheal flow with stenosis

BackgroundIn respiratory fluid dynamics research, it is typically assumed that the wall of the trachea is smooth. However, the trachea is structurally supported by a series of cartilaginous rings that create undulations on the wall surface, which introduce perturbations into the flow. Even though many studies use realistic Computer Tomography (CT) scan data to capture the complex geometry of the respiratory system, its limited spatial resolution does not resolve small features, including those introduced by the cartilaginous rings.ResultsHere we present an experimental comparison of two simplified trachea models with Grade II stenosis (70% blockage), one with smooth walls and second with cartilaginous rings. The use a unique refractive index-matching method provides unprecedented optical access and allowed us to perform non-intrusive velocity field measurements close to the wall (e.g., Particle Image Velocimetry (PIV)). Measurements were performed in a flow regime comparable to a resting breathing state (Reynolds number ReD = 3350). The cartilaginous rings induce velocity fluctuations in the downstream flow, enhancing the near-wall transport of momentum flux and thus reducing flow separation in the downstream flow. The maximum upstream velocity in the recirculation region is reduced by 38%, resulting in a much weaker recirculation zone— a direct consequence of the cartilaginous rings.ConclusionsThese results highlight the importance of the cartilaginous rings in respiratory flow studies and the mechanism to reduce flow separation in trachea stenosis.

Dynamic Rupture Models, Fault Interaction and Ground Motion Simulations for the Segmented Húsavík‐Flatey Fault Zone, Northern Iceland

AbstractThe Húsavík‐Flatey Fault Zone (HFFZ) is the largest strike‐slip fault in Iceland and poses a high seismic risk to coastal communities. To investigate physics‐based constraints on earthquake hazards, we construct three fault system models of varying geometric complexity and model 79 3‐D multi‐fault dynamic rupture scenarios in the HFFZ. By assuming a simple regional prestress and varying hypocenter locations, we analyze the rupture dynamics, fault interactions, and the associated ground motions up to 2.5 Hz. All models account for regional seismotectonics, topo‐bathymetry, 3‐D subsurface velocity, viscoelastic attenuation, and off‐fault plasticity, and we explore the effect of fault roughness. The rupture scenarios obey earthquake scaling relations and predict magnitudes comparable to those of historical events. We show how fault system geometry and segmentation, hypocenter location, and prestress can affect the potential for rupture cascading, leading to varying slip distributions across different portions of the fault system. Our earthquake scenarios yield spatially heterogeneous near‐field ground motions modulated by geometric complexities, topography, and rupture directivity, particularly in the near‐field. The average ground motion attenuation characteristics of dynamic rupture scenarios of comparable magnitudes and mean stress drop are independent of variations in source complexity, magnitude‐consistent and in good agreement with the latest regional empirical ground motion models. However, physics‐based ground motion variability changes considerably with fault‐distance and increases for unilateral compared to bilateral ruptures. Systematic variations in physics‐based near‐fault ground motions provide important insights into the mechanics and potential earthquake hazard of large strike‐slip fault systems, such as the HFFZ.

Study of natural convection heat transfer for a cylindrical and semicylindrical heat transfer system geometry

The paper presents the experimental and numerical study of the heat transfer parameters for the heated tube bank and arc-shaped plate made up of four tubes and four arc protrusions arranged one above the other. To evaluate the local heat transfer coefficients, the holographic interferometry is used as the experimental method, while the numerical simulations are performed by the Ansys Fluent software. The tube bank supplemented by the fin of different thickness and the double arc-shaped plate is further considered to improve the heat transfer parameters and the numerical results are compared with the basic arrangements. Considering the natural convection, the Rayleigh numbers are specified in the range of 16,460 to 46,340. It is observed that the tube bank achieves a higher average Nusselt number in the range of 37%–82% compared with the other arrangements depending on the Rayleigh number. The tube bank with fins does not increase the heat transfer parameters; however, there is an increase in average heat flux compared to the tube bank without fins. The double arc-shaped plate arrangement slightly increases the heat transfer and markedly increases the average heat flux compared to the single one. The highest average heat flux is achieved for the double arc-shaped plate and tube bank with fins in the range of 27.430 Wm-2 to 126.139 Wm-2.

Seismic observation of an active detachment faulting system beneath the Longqi hydrothermal field at the ultraslow spreading southwest Indian ridge

Hydrothermal processes in detachment settings at slow and ultraslow spreading ridges differ greatly from those at melt-rich faster spreading ridges. Active detachment faulting provides the possibility for off-axis high-temperature hydrothermal vents located far away from the heat source beneath the axial volcanic ridge. Seismic data from the slow spreading Mid-Atlantic ridge revealed that hydrothermal fluids may exploit detachment faults to extract heat from a melt zone near the crust-mantle interface. However, knowledge of the subsurface structure and the kinematic processes of detachment faults, and their interaction with hydrothermal fields at the slowest spreading ridges is still insufficient. Here, we report new insights on the seismicity beneath the Longqi hydrothermal field at the ultraslow spreading southwest Indian ridge from three ocean bottom seismometer monitoring experiments. The seismicity outlines the subsurface geometry of a detachment faulting system (DF1 and DF2). The strongly flexed DF1 (45°) is a mature detachment fault with a domed-shaped OCC where ultramafic rocks are exposed on the seafloor. An active young DF2 with intense earthquake activity along the steep subsurface (67°) suggests the initiation phase of rotation. The diversity of hydrothermal activities in the Longqi detachment-hydrothermal systems is closely related to the evolution of detachment faults. Additionally, both the non-transform discontinuity on the western margin of the Longqi-1 field and local faults facilitate hydrothermal circulation. Our study provides baseline observations for a Longqi-type of hydrothermal circulation at the inside corner associated with detachment faulting and non-transform offsets.

Combining entropy weight and TOPSIS method for selection of tank geometry and filler material of a packed-bed thermal energy storage system

Thermocline thermal energy storage systems are promising alternatives for recovering waste heat lost by industry around the world. The aim of this work is to extend the methodology presented in previous work, by optimising an existing industrial packed-bed storage system on two geometric optimisation variables, considering exergy, environmental and economic aspects. Seven filler materials are compared for the same heat transfer fluid, to include discrete variables in the model. The multi-objective optimisation problem is solved using the NSGA-II multi-objective genetic algorithm. For each filler material, a Pareto set is obtained. The non-dominated solutions within the union of the different Pareto sets are then selected, which give a new single set of optimised solutions. A multi-criteria decision-making method (TOPSIS) is then applied to obtain the optimal solution. To avoid any subjective choice from the decision-maker by determining the objective weights of each of the optimisation criteria, the Shannon entropy is used. The combination of TOPSIS and Shannon entropy led to the selection of a recycled ceramic obtained from hard coal ashes as the best filler. This solution has a stocky tank shape (2.4 m diameter, 2.1 m height) and a small particle diameter (7 mm). The exergy and environmental performance is improved compared to the reference storage. They reach 98.0% (vs 95.6%) and 58 hab.year (vs 67 hab.year) respectively. The levelised cost of energy is close to that of the reference tank (3.35 vs 3.31 c€/kWhth).