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A Modeling Analysis of Wastewater Heat Recovery Effects on Wastewater Treatment Plant Nitrification
Full text linkA global shift towards renewable energy production, driven primarily by the challenges posed by climate change, is currently underway. In this context, the utilization of heat recovery from municipal wastewater emerges as a promising green technology. Notably, the advantage of implementing energy recovery in sewers, as opposed to wastewater treatment plants (WWTPs), lies in the higher temperature of the wastewater and its proximity to potential heat users. Despite these benefits, concerns arise regarding the potential adverse effects on biological wastewater treatment processes downstream of the heat recovery section, particularly during colder seasons. This paper seeks to assess the impact of a heat recovery system along the sewer network on the efficiency of biological wastewater treatment processes. The methodology involves a modeling analysis of a real sewage network in Italy. Under typical northern Italy climate conditions, the results demonstrate the feasibility of heat recovery in sewers for WWTPs designed with a sludge residence time under aerobic conditions (SRTaer) greater than 13 days. In such cases, the nitrification process remains relatively unaffected. However, for lower SRTaer values, a case-specific feasibility assessment is recommended to evaluate the overall process efficiency comprehensively
A Study of Accelerated Corrosion of Stainless Steels under Highly Oxidizing Conditions
Full text linkThe corrosion behavior of certain steels under extremely oxidative conditions, simulating the impact of water radiolysis on stainless steels, has been investigated. Radiolysis generates aggressive species, including radicals, solvated electrons, and hydrogen peroxide, potentially leading to corrosion over time in materials typically considered resistant. To expedite the kinetics of this phenomenon, drastic conditions were employed, involving high concentrations of peroxide in a strongly acidic environment. Under these conditions, corrosion can manifest rapidly. The varied responses of different steels are contingent upon their inherent nature and chemical composition, notably the chromium and nickel content. Steels with higher chromium and nickel concentrations exhibit increased resistance to corrosion, even in such severe environments. Microscopic corrosion mechanisms involve pitting and intergranular corrosion. Pitting results in the formation of craters on surfaces, while intergranular corrosion leads to the detachment of grains
Analysis of the Flattening on Bi-2212 Wires Due to the Cabling Process and Its Effect on Their Performances
No full textBi-2212 superconducting round wire is one of the candidates for the development of magnets with fields largely above 20 T. One of the most crucial aspects is the possible wire degradation occurring in the cabling process, a mandatory step to achieve a very high current and essential for high field magnets. Here we report a general study on the performance's behaviour of Bi-2212 round wires following a deformation similar to that arising during the cabling assembly. Furthermore, we propose a preliminary 2D Finite Element Model to simulate the mechanical deformation that can be valuable to gain useful information for the development of high-quality cables. In the end, Bi-2212 wires we made and test don't show degradation, consistently with the results of the proposed model which confirms the reliability of the adopted assumptions
Wolbachia Infection through Hybridization to Enhance an Incompatible Insect Technique-Based Suppression of Aedes albopictus in Eastern Spain
No full textThe emergence of insecticide resistance in arbovirus vectors is putting the focus on the development of new strategies for control. In this regard, the exploitation of Wolbachia endosymbionts is receiving increasing attention due to its demonstrated effectiveness in reducing the vectorial capacity of Aedes mosquitoes. Here, we describe the establishment of a naïve Wolbachia infection in a wild Aedes albopictus population of eastern Spain through a hybridization approach to obtain males capable of sterilizing wild females. The obtained lines were compared with the Wolbachia donor, Ae. albopictus ARwP, previously artificially infected with Wolbachia wPip, regarding immature and adult survival, female fecundity, egg fertility, and level of induced sterility. Our results did not show significant differences between lines in any of the biological parameters analyzed, indicating the full suitability of the hybrids to be used as a control tool against Ae. albopictus. In particular, hybrid males induced 99.9% sterility in the eggs of wild females without the need for any preliminary treatment. Being harmless to non-target organisms and the environment, the use of this bacterium for the control of Ae. albopictus deserves further exploration. This is especially relevant in areas such as eastern Spain, where this mosquito species has recently spread and may represent a serious threat due to its competence as a vector for dengue, chikungunya, and Zika viruses
A Resonant-Cavity Antenna with High-Gain and Wide Bandwidth with an All-Dielectric 3D-Printed Superstrate
No full textThe 3D-printing of dielectric superstrates of Resonant Cavity Antennas has advantages of fast prototyping and flexibility in the realization of customized layouts. In this work, the low dielectric permittivity of test filaments is experimentally measured for their use in superstrates of Resonant Cavity Antennas. A suitable combination of thickness, side extension and permittivity of the superstrate can enhance the antenna gain of the primary source over a broad frequency interval. With non-periodic and perforated layouts, instead, the radiative properties can be improved in terms of reductions of the Side-Lobe Level. The use of an all-dielectric superstrate in the design of an RCA is presented, demonstrating the possibility of obtaining a broadband gain enhancement with a single dielectric layer of low permittivity
Thermo-Hydraulic Design of the First Wall of the DTT Facility
No full textThe main mission of the divertor tokamak test (DTT) facility is to study advanced solutions for the power exhaust issue in view of a fusion power plant. In this respect, a significant amount of heat is expected to be absorbed by the first wall (FW) during operation. Therefore, the DTT FW is designed to be an actively water-cooled system. A proper hydraulic model is needed for the development of a cooling architecture of the system able to fulfill the requirements of operational safety under thermal loads and compliance with the DTT plant specifications. The present study aims to address this challenge, offering practical inputs for further optimization. Based on the existing conceptual design, the cooling circuits have been setup inside the plasma-facing components (PFCs). In this phase, empirical equations and hydraulic simulations have been adopted to investigate the hydraulic behavior of the modules that make up the FW and to evaluate the main design parameters, namely, velocity and pressure drops in the cooling channels. The outcome of such analysis demonstrated that the current design of the FW system complies with the imposed requirements. Moreover, operating flexibility has been demonstrated by identifying a proper range of the mass flow rate for each subsystem. Therefore, the models implemented in this study and the obtained findings prove to be suitable to support the next activities of engineering design of the FW
Lithiated Nafion membrane as a single-ion conducting polymer electrolyte in lithium batteries
Full text linkSingle lithium-ion conducting polymer electrolytes are promising candidates for next generation safer lithium batteries. In this work, Li+-conducting Nafion membranes have been synthesized by using a novel single-step procedure. The Li-Nafion membranes were characterized by means of small-wide angle X-ray scattering, infrared spectroscopy and thermal analysis, for validating the proposed lithiation method. The obtained membranes were swollen in different organic aprotic solvent mixtures and characterized in terms of ionic conductivity, electrochemical stability window, lithium stripping-deposition ability and their interface properties versus lithium metal. The membrane swollen in ethylene carbonate:propylene carbonate (EC:PC, 1:1 w/w) displays good temperature-activated ionic conductivities (σ ≈ 5.5 × 10–4 S cm−1 at 60 °C) and a more stable Li-electrolyte interface with respect to the other samples. This Li-Nafion membrane was tested in a lithium-metal cell adopting LiFePO4 as cathode material. A specific capacity of 140 mAhg−1, after 50 cycles, was achieved at 30 °C, demonstrating the feasibility of the proposed Li-Nafion membrane
Materials for a catalog of Italian earthquakes: update of AMGNDT95 (1821-1905) early studies and investigation of the 1981 Castelli Romani earthquake
No full textThe Parametric Catalogue of Italian Earthquakes (CPTI15), includes almost 5000 events; among them there are about two hundred earthquakes scarcely studied, belonging to the AMGNDT995 database, whose parametrization remains very uncertain. Five of these earthquakes are revised in this paper, with the aim of appraising their knowledge and enriching them with better information and data. In addition, we present here an event not listed in the Italian seismic catalogues that occurred in the Colli Albani volcanic district, near Rome, in 1981
Comparative Analysis of Vacuum Feedthroughs for the DTT ICRH System
No full textThis article reports a very preliminary analysis of five different feedthroughs for the ICRH system of the Divertor Tokamak Test (DTT) facility, designed by the Italian DTT Limited Liability Consortium (S.C. a r.l.). The analysis has been performed from the RF perspective using the ANSYS HFSS code with the aim of defining the most efficient feedthrough for the DTT ICRH system
Overview of tritium management in WCLL test blanket system of ITER
No full textA key aspect for the achievement of the fuel self-sufficiency of future fusion power plants is the management of tritium in the different stages of the reactor fuel cycle. In particular, one of the greatest challenges for the success of liquid metal breeder concepts such as the Water-Cooled Lithium-Lead (WCLL) is the extraction of tritium from the liquid LiPb eutectic alloy (15.7 at.%Li), which fulfils the main functions of tritium breeder, tritium carrier and neutron multiplier, and the processing in a form suitable for an accurate tritium accountancy. Within this frame, significant advancements have been carried out in the last years as regards the WCLL Test Blanket System (TBS) of ITER. Tritium is mainly produced inside the LiPb and extracted through the Tritium Extraction Unit (TEU). The reference technology for the TEU of the WCLL-TBS is the Gas-Liquid Contactor (GLC) in the packed-column configuration. Tritium is then concentrated in ZrCo getter beds before being sent to the accountancy system where different technologies for both static and dynamic accountancy are adopted in order to provide precise and reliable tritium measurements, which are an essential need in view of an application to the European DEMO reactor. In this paper, the present status and the design solutions foreseen for tritium management in WCLL-TBS are presented and discussed. The implementation and optimization of the conceptual design of the lithium-lead loop (LLP), the Tritium Extraction System (TES) and the Tritium Accountancy System (TAS) have been performed in order to manage tritium concentration in LiPb and in the ancillary systems