NUMERICAL AND LABORATORY STUDY OF SEISMIC WAVES PROPAGATION, TEMPERATURE EFFECTS AND FLUID FLOWS IN MULTILAYERED MEDIA

Steel production by continuous casting is nowadays the most efficient method and the one that yields the best quality semi-finished products. The types of steel that can be produced varies greatly depending on the composition of the mixtures, the casting powders used to prevent oxidation and reduce heat loss, the cooling rate, and many other factors. During continuous casting, heat from the molten steel must be removed in large quantities and quickly to allow the first layer of solid skin to be created, so the continuous casting moulds, i.e. large hollow tubes generally made of copper alloys, are immersed in a conveyor with a closed water circuit where water circulates at high speed and pressure. In addition to water, there are also other parameters that can be monitored to increase production quality, such as powder deposition on the casting bath and steel level control. It would be useful to have automatic systems capable of replacing manual human control, to avoid the hazardous situations obviously present in steel mills, but also to increase knowledge of the production process through the acquisition of reliable data. This research aims to experimentally explore the possibility of measuring the level of molten steel in the mould by making time-of-flight measurements in the wall of the ingot using ultrasonic transducers similar the ones used for non-destructive testing of materials. These time-of-flight measurements are then converted to temperature and determine a thermal profile along the mould wall, from which the steel level is derived using an ad-hoc constructed algorithm. The research activity was divided into the realization of a real-time hardware and software system that was eventually adopted in real production systems as well. To understand how to design an initial prototype and how to choose the key parameters of the measurement system, a numerical model was implemented to simulate Gaussian beams, which are used to approximate the propagation of ultrasonic beams in even heterogeneous media, as in this case. The results obtained, both from numerical simulations and laboratory tests, made it possible to implement a first measurement tool that adopted a technique already known in the literature but innovative in the sense of application to an industrial context such as continuous castingSteel production by continuous casting is nowadays the most efficient method and the one that yields the best quality semi-finished products. The types of steel that can be produced varies greatly depending on the composition of the mixtures, the casting powders used to prevent oxidation and reduce heat loss, the cooling rate, and many other factors. During continuous casting, heat from the molten steel must be removed in large quantities and quickly to allow the first layer of solid skin to be created, so the continuous casting moulds, i.e. large hollow tubes generally made of copper alloys, are immersed in a conveyor with a closed water circuit where water circulates at high speed and pressure. In addition to water, there are also other parameters that can be monitored to increase production quality, such as powder deposition on the casting bath and steel level control. It would be useful to have automatic systems capable of replacing manual human control, to avoid the hazardous situations obviously present in steel mills, but also to increase knowledge of the production process through the acquisition of reliable data. This research aims to experimentally explore the possibility of measuring the level of molten steel in the mould by making time-of-flight measurements in the wall of the ingot using ultrasonic transducers similar the ones used for non-destructive testing of materials. These time-of-flight measurements are then converted to temperature and determine a thermal profile along the mould wall, from which the steel level is derived using an ad-hoc constructed algorithm. The research activity was divided into the realization of a real-time hardware and software system that was eventually adopted in real production systems as well. To understand how to design an initial prototype and how to choose the key parameters of the measurement system, a numerical model was implemented to simulate Gaussian beams, which are used to approximate the propagation of ultrasonic beams in even heterogeneous media, as in this case. The results obtained, both from numerical simulations and laboratory tests, made it possible to implement a first measurement tool that adopted a technique already known in the literature but innovative in the sense of application to an industrial context such as continuous castin

Aquatic Angiosperm Transplantation: A Tool for Environmental Management and Restoring in Transitional Water Systems

Since the 1960s, the Venice Lagoon has suffered a sharp aquatic plant constriction due to eutrophication, pollution, and clam fishing. Those anthropogenic impacts began to decline during the 2010s, and since then the ecological status of the lagoon has improved, but in many choked areas no plant recolonization has been recorded due to the lack of seeds. The project funded by the European Union (LIFE12 NAT/IT/000331-SeResto) allowed to recolonize one of these areas, which is situated in the northern lagoon, by widespread transplantation of small sods and individual rhizomes. In-field activities were supported by fishermen, hunters, and sport associations; the interested surface measured approximately 36.6 km2. In the 35 stations of the chosen area, 24,261 rhizomes were transplanted during the first year, accounting for 693 rhizomes per station. About 37% of them took root in 31 stations forming several patches that joined together to form extensive meadows. Plant rooting was successful where the waters were clear and the trophic status low. But, near the outflows of freshwater rich in nutrients and suspended particulate matter, the action failed. Results demonstrate the effectiveness of small, widespread interventions and the importance of engaging the population in the recovery of the environment, which makes the action economically cheap and replicable in other similar environments

Efficient preconditioners for solving dynamical optimal transport via interior point methods

International audienceIn this paper we address the numerical solution of the quadratic optimal transport problem in its dynamical form, the so-called Benamou-Brenier formulation. When solved using interior point methods, the main computational bottleneck is the solution of large saddle point linear systems arising from the associated Newton-Raphson scheme.The main purpose of this paper is to design efficient preconditioners to solve these linear systems via iterative methods. Among the proposed preconditioners, we introduce one based on the partial commutation of the operators that compose the dual Schur complement of these saddle point linear systems, which we refer as $\boldsymbol{B}\boldsymbol{B}$-preconditioner.A series of numerical tests show that the $\boldsymbol{B}\boldsymbol{B}$-preconditioner is the most efficient among those presented, despite a performance deterioration in the last steps of the interior point method. It is in fact the only one having a CPU-time that scales only slightly worse than linearly with respect to the number of unknowns used to discretize the problem

Efficient preconditioners for solving dynamical optimal transport via interior point methods

In this paper we address the numerical solution of the quadratic optimal transport problem in its dynamical form, the so-called Benamou-Brenier formulation. When solved using interior point methods, the main computational bottleneck is the solution of large saddle point linear systems arising from the associated Newton-Raphson scheme. The main purpose of this paper is to design efficient preconditioners to solve these linear systems via iterative methods. Among the proposed preconditioners, we introduce one based on the partial commutation of the operators that compose the dual Schur complement of these saddle point linear systems, which we refer as BB-preconditioner. A series of numerical tests show that the BB-preconditioner is the most efficient among those presented, with a CPU-time scaling only slightly more than linearly with respect to the number of unknowns used to discretize the problem

Clinical and Cytometric Study of Immune Involvement in a Heterogeneous Cohort of Subjects With RASopathies and mTORopathies

RASopathies and mTORopathies are groups of genetic syndromes associated with increased activation of the RAS-MAPK or the PI3K-AKT-mTOR pathway, resulting in altered cell proliferation during embryonic and postnatal development. The RAS-MAPK and the PI3K-AKT-mTOR pathways are connected to each other and play a crucial role in adaptive immunity. However, with the exception of Activated PI3K delta syndrome (APDS), immune function has not been deeply studied in these disorders. We collected clinical and immunophenotypic data of a cohort of patients with RASopathies and mTORopathies. Overall, we enrolled 47 patients (22 females, 25 males, age 2\u201340 years): 33 with neurofibromatosis type 1, 11 Noonan syndrome and 3 Bannayan-Riley-Ruvalcaba syndrome. 8 patients reported a history of invasive infections requiring hospitalization and intravenous antibiotic therapy. Only 3 patients reported a history of unusual, difficult-to-treat or deep-seated infection. Adenotonsillectomy was performed in 11 patients (24%). However, in most cases (83%) patients\u2019 parents did not perceive their child as more prone to infections than their peers. Lymphocyte subpopulations were analyzed in 37 of the 47 patients (16 female, 21 males, age 1\u201340 years). Among the studied lymphocyte subsets, the only consistent alteration regarded an increased percentage of immature B cells (recent bone marrow emigrants) in 34 out of 37 (91,9%) patients, and an increased percentage of double negative T cells in 9 patients. In conclusion, although borderline immune abnormalities were present in a significant proportion of subjects and adenotonsillectomy was performed more frequently than expected for the general population, no major immune disturbance was found in this cohort of patients

Macrofite e stato ecologico dell'area individuata per il passaggio delle grandi navi nella laguna di Venezia

Macrophyte distribution and the main ecological parameters of the area between the historical centre of Venice and the industrial area of Porto Marghera were investigated. A map of macrophytes was carried out by sampling 150 sites in July 2015. Four sites were monitored from July to October 2015 by sampling both macrophytes and nutrient concentrations in the water column and surface sediments. The aim was to determine the trophic conditions and the ecological status of that area before the digging of a new canal to create a new access to the large ships that arrive in Venice