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Development of Ca/K-1144 IBS Wires with Composite Cu/Ta Sheaths
No full textCa/K-1144 compounds constitute promising materials to be exploited for the fabrication of Iron Based Superconductors (IBSC) wires via the Powder in Tube (PIT) method thanks to the high critical currents observed in single crystals coupled to the simple and robust chemical composition. The production of Ca/K-1144 wires has been however hindered by the reactivity of Ca with Ag, the common choice for sheath materials in IBSC wires. In our recent work, we demonstrated the potentiality of composite Cu/Ta sheaths to be adopted for these kinds of applications. In this work, we show the effect of the variation of sintering temperature and mechanical processing on the morpho-structural and superconducting properties of wires processed through this combination of materials. While critical currents are still to be improved, compared to state of the art 122-Ag wires, with evident margins for what concerns both the synthesis step and the wire production process, the results show how sintering temperature can be raised up to 900 °C. The intrinsic fragility of pure Ta observed during the wire processing is proposed to be mitigated by tailoring the sheath dimensions or the Ta barrier chemical composition
A new method for rapidly capturing the strength and full nonlinear response of partially interacting steel–concrete composite beams
Get PDFA semi-analytical procedure is presented for predicting the complete flexural response of partially interacting steel–concrete composite beams up to failure. The governing equation of the Euler–Bernoulli beam theory is solved wherein concrete, steel and the shear connectors joining the concrete slab to the steel beam are assumed to have nonlinear stress-deformation relationships. The adopted constitutive relationship for the connectors allows for partial or full composite action. The solution is applicable to beams and one-way slabs subjected to concentrated or uniform load and/or their combination. The governing equation is numerically solved by satisfying the equilibrium and compatibility requirements along the member. For the reinforced concrete part of the composite beam, a nonlinear moment–curvature relationship is developed that accounts for concrete nonlinearity in compression and for cracking and tension-stiffening in tension as well as for steel reinforcement nonlinearity. The steel profile is assumed to have a bilinear elasto–plastic strain-hardening moment–curvature relationship. Comparison of the proposed model results with the corresponding experimental load–deflection curves and interfacial shear–slip curves of several beams tested by others shows good agreement. The relative simplicity, efficiency and easy application of the present solution make it possible to accurately predict the failure load, interfacial slip and full nonlinear response of partially interacting composite beams
Flexible Charging to Energy Saving—Strategies Assessment with Big Data Analysis for PHEVs Private Cars
Get PDFIn road transport, most vehicles today still rely on internal combustion engines. However, these engines have lower efficiency and generate higher pollution levels compared to electric motors. Consequently, there is a growing interest in the transition from conventional vehicles to electric ones. However, the transition to an electrified road transport system is not without challenges. Among these, the impact that electric vehicle charging will have on the electricity grid is of particular concern. This paper analyzes different charging scenarios for plug-in hybrid electric vehicles (PHEVs) and proposes charging strategies to minimize their impact on the electricity grid. The analysis is based on a large dataset of trips in urban areas in Italy. The study shows that smart charging of PHEVs can be implemented to minimize the impact on the electricity grid. The implementation of optimized charging strategies can contribute to making PHEVs a valid, eco-sustainable alternative to conventional vehicles while also promoting the stability and efficiency of the electricity grid. The study aims to verify the effectiveness and efficiency of the flexible charging strategy by comparing the common charging operation (first in–first out) with other, less impactful charging schemes
Influence of Rare-Earth Inclusion on Structure and Properties of Ca/K-1144 IBSC
Get PDFAmong Iron Based superconductors (IBSC), the compounds belonging to the 1144 family are characterized by the A1AE1Fe4As4 chemical composition (A = Alkaline, AE = Alkaline-Earth) and considered stoichiometric. In recent experiments, we obtained 1144 samples characterized by different levels of alkali and alkaline earth metals substitutions and demonstrated how the lattice distortion induced by such variation in the chemical composition plays a fundamental role on critical temperature values. In this work, we investigate the possibility to obtain Ca/K-1144 compounds substituted with Rare-Earth (RE) elements. We produced polycrystalline samples in which RE ions partially replace Ca ions in the 1144 phase. The lattice structure is consistently affected by the substituent element inducing a contraction of the c-axis. Multiple substitution of RE and A or AE elements was also attempted, showing that appropriate combinations allow simultaneous inclusion of different elements in the structure. For compounds that include RE elements, the critical temperature of the samples appears to follow to the same trend with respect to the distortion of the crystal lattice induced by A and AE substitutions
Innovative Nafion- and Lignin-Based Cation Exchange Materials Against Standard Resins for the Removal of Heavy Metals During Water Treatment
Get PDFThe contamination of water by heavy metals poses an escalating risk to human health and the environment, underscoring the critical need for efficient removal methods to secure safe water resources. This study evaluated the performance of four cationic exchange materials (labeled “PS—DVB”, “PA—DVB”, “TFSA”, and “OGL”) in removing or harvesting metals such as copper, silver, lead, cobalt, and nickel from aqueous solutions, several of which are precious and/or classified as Critical Raw Materials (CRMs) due to their economic importance and supply risk. The objective was to screen and benchmark the four ion exchange materials for water treatment applications by investigating their metal sequestration capacities. Experiments were conducted using synthetic solutions with controlled metal concentrations, analyzed through ICP-OES, and supported by kinetic modeling. The adsorption capacities (qe) obtained experimentally were compared with those predicted by pseudo-first-order and pseudo-second-order models. This methodology enables high precision and reproducibility, validating its applicability for assessing ion exchange performance. The results indicated that PS—DVB and PA—DVB resins proved to be of “wide range”, exhibiting high efficacy for most of the metals tested, including CRM-designated ones, and suggesting their suitability for water purification. Additionally, the second-life Nafion-based “TFSA” material demonstrated commendable performance, highlighting its potential as a viable and technologically advanced alternative in water treatment. Lastly, the lignin-based material, “OGL”, representing the most innovative and sustainability apt option, offered relevant performance only in selected cases. The significant differences in performance among the resins underscore the impact of structural and compositional factors on adsorption efficiency. This study offers valuable insights for investigating and selecting new sustainable materials for treating contaminated water, opening new pathways for targeted and optimized solutions in environmental remediation
Research and Development Status for an Innovative Crystal Calorimeter for the Future Muon Collider
No full textAccurate measurements of physical processes in high energy frontier experiments demand exceptional spatial, temporal, and energy precision to discern the physics behind high-energy particle jets. Calorimeters, like other detection systems, must be able to meet these increasingly challenging performance requirements. In the prospective TeV-scale Muon Collider, the primary hurdle in designing detectors and devising event reconstruction algorithms is the challenge posed by Beam-Induced Background (BIB). Nevertheless, it is conceivable to mitigate the impact of BIB on the Muon Collider's calorimeter by capitalizing on certain characteristics and ensuring key features such as high granularity, precise timing, longitudinal segmentation, and superior energy resolution. This is what the here described Research and Development is trying to achieve with an innovative semi-homogeneous electromagnetic calorimeter constructed from stackable and interchangeable modules composed of lead fluoride crystals (PbF2). These modules are equipped with surface-mount UV-extended Silicon Photomultipliers (SiPMs) and are collectively referred to as the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The challenge lies in making sure this calorimeter can operate effectively within an extremely harsh radiation environment, enduring an annual neutron flux of 1014 n1MeV/cm2 and a total ionizing dose (TID) of 10 kGy. In this article, the radiation tolerance measured in several irradiation campaigns is discussed, and the timing performances during a test beam at CERN-H2 with 120-GeV electrons. Additionally, a description of the latest prototype, Proto-1, is provided together with the results of the latest low-energy beam test at the LNF beam test facility (BTF) with 450 MeV electrons
Developing an alternative calorimeter solution for the future Muon Collider: The Crilin design
Get PDFThe Crilin calorimeter represents a novel approach in the development of electromagnetic calorimeters for future colliders, especially for a Muon Collider. This paper details the design and performance of the innovative semi-homogeneous Crilin calorimeter, highlighting its capabilities in mitigating beam-induced backgrounds (BIB) while maintaining excellent time resolution (less than 50 ps), longitudinal segmentation, and fine granularity. These performances are achieved throughout a series of stackable and interchangeable lead fluoride (PbF2) crystal matrices readout by surface-mount UV-extended Silicon Photo-multipliers. Simulated and experimental results demonstrate the Crilin design's potential to work as an efficient and cost-effective alternative to traditional electromagnetic calorimeters. Crilin radiation tolerance is discussed, as measured in several irradiation campaigns, as well as timing performances during a beam test at CERN-H2 with 120 GeV electrons for the latest prototype, Proto-1. Additionally, a description of the results from a recent beam test conducted at the LNF Beam Test Facility with 450 MeV electrons is provided, aiming to measure light yield losses due to irradiation
A novel numerical approach for analyzing experimental data on critical current degradation in Nb3Sn wires caused by transverse deformations preceding heat treatment
Get PDFIn the framework of studies on high-field magnets for future accelerators, a specific project called ASTRACT focuses on the effect of transverse strain on the critical current of Nb3Sn wires. The first phase of the project addresses the effects of strain imposed on Nb3Sn wires before heat treatment and the development of a procedure to directly compare critical current measurements with values extracted from magnetization cycles. A Nb3Sn RRP-Ti wire was deformed to different values of transverse strain (10%, 15%, 20%, and 25%), and long samples were collected for transport measurements at 4.2 K, in a background field ranging from 10 to 14 T. Short samples were used for magnetization measurements (VSM technique). Additionally, SEM images of the cross-section were collected at different longitudinal positions along the wire for each strain value. This paper proposes a method based on SEM image analysis and magnetization measurements analysis to study the effect of bundle deformation on transport properties. The procedure requires morphological information provided by SEM images after appropriate numerical processing. Verification through statistical comparison between the Ic transport and VSM data is also conducted. Direct critical current measurements showed no degradation due to deformation up to 25%. The method introduced, independent of transport data, can reach the same conclusions by considering the real shape of the bundles
Investigating the effects of the greenery increase on air temperature, ventilation and cooling energy demand in Melbourne with the Weather Research and Forecasting model and Local Climate Zones
Get PDFVegetation has a well-known potential for mitigating urban overheating. This work aims to explore the effects of enhancing urban greenery in Melbourne (Australia) through a configuration of the Weather Research and Forecasting (WRF) model including the Building Effect Parameterization and the Local Climate Zones and presents novelties in: i) covering two-months and ii) focusing on air circulation and buildings cooling energy demand through the ventilation coefficient (VC) and the cooling degree hours (CDHs). A control case and two “what-if” scenarios with a growing green coverage equal to 35 % (control case), 50 % (modest increase) and 60 % (robust increase) have been designed and then simulated for January and February 2019. Outcomes reveal a maximum drop in 2 m temperature of approximately 0.4 °C and 0.8 °C at 14:00 LT for the modest and robust green increase scenario, respectively. The urban-rural energy surplus for cooling buildings is reduced and even counterbalanced. Peak CDHs decrease from 143 °C·h of the control case to 135 °C·h (modest increase) and 126 °C·h (robust increase), while they measure 137 °C·h in the non-urban areas. Average wind speed increases by 0.8 m/s (equal to 22 % with respect to the control case). Furthermore, adding urban greenery has an unfavorable implication on VC (maximum reduction of 500 m2s−1) with a consequent deterioration of the transport and dispersion of pollutants. Middle- and high-density classes are touched more than low-density by the VC reduction. In addition, the benefits of enhancing urban greenery concern physiologically and psychologically the quality of life of the dwellers