Comparison of viscoelastic models with a different number of parameters for transient simulations

AbstractThe numerical and analytical models used for transient simulations, and hence for the pressurized pipe system diagnosis, require the definition of a rheological component related to the pipe material. The introduction and the following widespread use of polymeric material pipes, characterized by a viscoelastic behavior, increased the complexity and the number of parameters involved in this component with respect to metallic materials. Furthermore, since tests on specimens are not reliable, a calibration procedure based on transient test is required to estimate the viscoelastic parameters. In this paper, the trade-off between viscoelastic component accuracy and simplicity is explored, based on the Akaike criterion. Several aspects of the calibration procedure are also examined, such as the use of a frequency domain numerical model and of different standard optimization algorithms. The procedure is tested on synthetic data and then it is applied to experimental data, acquired during transients on a high density polyethylene pipe. The results show that the best model among those used for the considered system implements the series of a spring with three Kelvin–Voigt elements

A New Pd-Based Catalytic System for the Reductive Carbonylation of Nitrobenzene to Form N-(4-hydroxyphenyl)acetamide Selectively in One Pot

N-(4-hydroxyphenyl)acetamide (commonly named paracetamol or acetaminophen) is a target molecule for many industries that produce chemicals for pharmaceutical applications. The industrial processes, however, use multistep procedures with low overall yield and/or severe drawbacks and problems in terms of sustainability. In the present paper, a one-pot synthesis is proposed based on the reductive carbonylation of nitrobenzene catalyzed by Pd(II)-complexes. Usually, such a reaction leads to a mixture of different products, including aniline, 4-aminophenol and 1,3-diphenylurea. However, the selectivity towards the possible products strongly depends by the ligands on the Pd(II)-catalyst, but also by the nature of the solvent. According to this, we have found that when the reaction was carried out in dilute acetic acid as a solvent, the [PdCl2(dppb)] catalyst precursor leads in one pot to N-(4-hydroxyphenyl)acetamide. Under optimized reaction conditions, it was possible to produce N-(4-hydroxyphenyl)acetamide with a 85 mol % of selectivity in ca. 5 h

Multi-domain analysis and prediction of the light emitted by an inductively coupled plasma jet

Inductively coupled plasma wind tunnels are crucial for replicating hypersonic flight conditions in ground testing. Achieving the desired conditions (e.g., stagnation-point heat fluxes and enthalpies during atmospheric reentry) requires a careful selection of operating inputs, such as mass flow, gas composition, nozzle geometry, torch power, chamber pressure, and probing location along the plasma jet. The study presented herein focuses on the influence of the torch power and chamber pressure on the plasma jet dynamics within the 350 kW Plasmatron X ICP facility at the University of Illinois at Urbana-Champaign. A multi-domain analysis of the jet behavior under selected power-pressure conditions is presented in terms of emitted light measurements collected using high-speed imaging. We then use Gaussian Process Regression to develop a data-informed learning framework for predicting Plasmatron X jet profiles at unseen pressure and power test conditions. Understanding the physics behind the dynamics of high-enthalpy flows, particularly plasma jets, is the key to properly design material testing, perform diagnostics, and develop accurate simulation modelsComment: 22 pages (including figures, appendix, and references); 13 figure

Characterizing the effects of water distribution system topology modifications on its dynamic behaviour through connectivity metrics

[EN] Water distribution networks (WDNs) are complex combinations of nodes and links and their structure has an impact on their behaviour, considering both quantitative (i.e. related to pipe flows and nodal pressures) and qualitative (i.e. related to water age and quality) aspects. The complexity of WDNs has been the basis of several studies that have resorted to the graph theory to relate connectivity properties to system behaviour (e.g. its reliability and water age/quality), evaluated under the assumption of steady-state conditions. Within this framework, in recent years the tendency toward reducing network interconnection through the closure of isolation valves has emerged, mainly to (i) facilitate its monitoring and management, and (ii) increase flow velocity and reduce water age. However, changes in the topology of a network can affect not only aspects evaluated under the assumption of steady-state conditions, but also its dynamic behaviour. Based on these considerations, the present study investigates whether some metrics derived from graph theory, already applied in the context of networks’ steady-state analyses, can also provide useful indications for assessing the effects of changes in the topological structure, which could be consequences of branching operations, on the dynamic response of a network subjected to users’ activity. The analyses highlight that connectivity metrics can reflect the pressure dynamic behaviour of the hydraulic systems and support in their macroscopic understanding during design and management operations. Thus, their application can be effectively extended from the steady-state to the dynamic framework.Marsili, V.; Alvisi, S.; Maietta, F.; Capponi, C.; Meniconi, S.; Brunone, B.; Franchini, M. (2024). Characterizing the effects of water distribution system topology modifications on its dynamic behaviour through connectivity metrics. Editorial Universitat Politècnica de València. https://doi.org/10.4995/WDSA-CCWI2022.2022.1401

Anomaly pre-localization in distribution–transmission mains by pump trip: preliminary field tests in the Milan pipe system

In this paper, the reliability of transients due to pump trip as a powerful tool for the pre-localization of anomalies in real pipe systems is tested. The examined pipe system is part of the one supplying the city of Milan, Italy and is managed by Metropolitana Milanese SpA (MM). The characteristics of such a system can be considered as intermediate between those of classical transmission mains and distribution systems because of its several branches. A Lagrangian model simulating pressure wave propagation is used to evaluate the pipe pressure wave speed – associated with a genetic algorithm – and to locate possible anomalies – associated with wavelet analysis. The results of the diagnosis of the pipe system are corroborated by repairs executed by MM in the area where possible anomalies have been pre-localized

IR.IDE Itinerari 2018-2022

La mostra IR.IDE Itinerari 2018—2022 ricompone in forma visuale gli studi sviluppati nell’ambito dell’Infrastruttura di Ricerca Integral Design Environment (IR.IDE). Nata nel 2018 con il Dipartimento di eccellenza di Culture del Progetto dell’Università Iuav di Venezia, IR.IDE dal 2021 è riconosciuta come infrastruttura di ricerca di interesse regionale. L’esposizione coinvolge i lavori di oltre trenta studiosi, tra assegnisti di ricerca e dottorandi, che hanno contribuito alla crescita dell’infrastruttura insieme alla direzione, ai responsabili scientifici dei laboratori e dei centri, al comitato scientifico, ai visiting professor, al personale di segreteria e al personale tecnico amministrativo. A partire dalla struttura relazionale definita dal progetto di un database delle ricerche (d.IDE), l’esposizione ricompone geografie e narrazioni integrali, visualizzando itinerari che si avvalgono di parole chiave e immagini evocative per richiamare premesse, relazioni, processi ed esiti delle ricerche. Video, pannelli grafici e modelli tracciano un percorso in cui è possibile riconoscere prospettive integrali, tra riflessioni sul concetto di Made in Italy e nuove possibili traiettorie progettuali

Impacto de la inoculación con micorrizas y el riego en la sobrevivencia de plántulas de Pinus radiata D. Don sometidas a sequía

In drought condition, plants increase survival chance by adjusting their functional traits and by biological associations. Mycorrhizae association and artificial watering have been shown to increase plant survival under drought, especially at early developmental stages when plants are more susceptible. In Chile, Pinus radiata is the most important forest species. It is grown mainly in Central Chile, where precipitations are predicted to drop in 40% and change in frequency in the future due to climate change. Rhizopogon luteolus is an ectomycorrhizae usually associated with Pinus species and has been found to increase drought tolerance. We addressed the effect of R. luteolus inoculation on survival and functional traits of P. radiata seedlings exposed to two watering treatments. These treatments simulated control (50 ml) and 40% reduced precipitations (20 ml). We also evaluated the combined effect of watering quantity (20 and 50 ml) and frequency (every 5, 10 and 30 days) on the same variables. R. luteolus inoculation increased seedling survival, but reduced plant size. Watering quantity affected plant survival only at intermediate watering frequencies, but not at the high and low frequencies. The lowest frequency, normal for the summer of Central Chile, resulted in ?80% seedling mortality. Most of the functional traits measured were not affected neither by watering frequency nor quantity, but they were affected by mycorrhization. Mycorrhizae inoculation, together with some sort of artificial watering could be a possible strategy to cope with prolonged drought events.En condiciones de sequía, las plantas aumentan la probabilidad de sobrevivir ajustando sus rasgos funcionales y por medio de asociaciones biológicas. Las asociaciones micorrícicas y el riego artificial aumentan la sobrevivencia en condiciones de sequía, especialmente en etapas tempranas del desarrollo, cuando las plantas son más sensibles. En Chile, Pinus radiataes la especie forestal más importante. Se planta principalmente en Chile central, donde se predice que las precipitaciones disminuirán en un 40% y cambiará su frecuencia en el futuro debido al cambio climático. Rhizopogon luteolus es una ectomicorriza usualmente asociada a especies de Pinus y se ha encontrado que aumenta la tolerancia a la sequía. Se analizó el efecto de la inoculación de R. luteolus en la sobrevivencia y rasgos funcionales de plántulas de P. radiata expuestas a dos tratamientos de riego. Estos tratamientos simulan precipitaciones control (50 ml) y reducidas a un 40% (20 ml). También se evaluó el efecto combinado de la cantidad (20 y 50 ml) y frecuencia (cada 5, 10 y 30 días) de riego en las mismas variables. La inoculación con R. luteolus aumentó la sobrevivencia pero redujo el tamaño de las plántulas. La cantidad de riego afectó la sobrevivencia de las plantas sólo en la frecuencia intermedia de riego, pero no en las frecuencias alta y baja. La frecuencia más baja, normal para el verano de Chile central, resultó en ?80% de mortalidad de plántulas. La mayoría de los rasgos funcionales no fueron afectados por la frecuencia o cantidad de riego, pero si por la micorrización. La inoculación con micorrizas, en conjunto con algún tipo de riego artificial, podría ser una posible estrategia para lidiar con eventos de sequía prolongada

Molecular Chaperones in the Pathogenesis of Amyotrophic Lateral Sclerosis: The Role of HSPB1

open15siGenetic discoveries in amyotrophic lateral sclerosis (ALS) have a significant impact on deciphering molecular mechanisms of motor neuron degeneration but, despite recent advances, the etiology of most sporadic cases remains elusive. Several cellular mechanisms contribute to the motor neuron degeneration in ALS, including RNA metabolism, cellular interactions between neurons and nonneuronal cells, and seeding of misfolded protein with prion-like propagation. In this scenario, the importance of protein turnover and degradation in motor neuron homeostasis gained increased recognition. In this study, we evaluated the role of the candidate gene HSPB1, a molecular chaperone involved in several proteome-maintenance functions. In a cohort of 247 unrelated Italian ALS patients, we identified two variants (c.570G>C, p.Gln190His and c.610dupG, p.Ala204Glyfs*6). Functional characterization of the p.Ala204Glyfs*6 demonstrated that the mutant protein alters HSPB1 dynamic equilibrium, sequestering the wild-type protein in a stable dimer and resulting in a loss of chaperone-like activity. Our results underline the relevance of identifying rare but pathogenic variations in sporadic neurodegenerative diseases, suggesting a possible correlation between specific pathomechanisms linked to HSPB1 mutations and the associated neurological phenotype. Our study provides additional lines of evidence to support the involvement of HSPB1 in the pathogenesis of sporadic ALS.openCapponi, Simona; Geuens, Thomas; Geroldi, Alessandro; Origone, Paola; Verdiani, Simonetta; Cichero, Elena; Adriaenssens, Elias; De Winter, Vicky; Bandettini di Poggio, Monica; Barberis, Marco; Chiò, Adriano; Fossa, Paola; Mandich, Paola; Bellone, Emilia; Timmerman, VincentCapponi, Simona; Geuens, Thomas; Geroldi, Alessandro; Origone, Paola; Verdiani, Simonetta; Cichero, Elena; Adriaenssens, Elias; De Winter, Vicky; BANDETTINI DI POGGIO, MONICA LAURA; Barberis, Marco; Chiò, Adriano; Fossa, Paola; Mandich, Paola; Bellone, Emilia; Timmerman, Vincen

Clinical outcome with different doses of low-molecular-weight heparin in patients hospitalized for COVID-19

A pro-thrombotic milieu and a higher risk of thrombotic events were observed in patients with CoronaVirus disease-19 (COVID-19). Accordingly, recent data suggested a beneficial role of low molecular weight heparin (LMWH), but the optimal dosage of this treatment is unknown. We evaluated the association between prophylactic vs. intermediate-to-fully anticoagulant doses of enoxaparin and in-hospital adverse events in patients with COVID-19. We retrospectively included 436 consecutive patients admitted in three Italian hospitals. Outcome according to the use of prophylactic (4000IU) vs. higher (>4000IU) daily dosage of enoxaparin was evaluated. The primary end-point was in-hospital death. Secondary outcome measures were in-hospital cardiovascular death, venous thromboembolism, new-onset acute respiratory distress syndrome (ARDS) and mechanical ventilation. A total of 287 patients (65.8%) were treated with the prophylactic enoxaparin regimen and 149 (34.2%) with a higher dosing regimen. The use of prophylactic enoxaparin dose was associated with a similar incidence of all-cause mortality (25.4% vs. 26.9% with the higher dose; OR at multivariable analysis, including the propensity score: 0.847, 95% CI 0.400-0.1.792; p=0.664). In the prophylactic dose group, a significantly lower incidence of cardiovascular death (OR 0.165), venous thromboembolism (OR 0.067), new-onset ARDS (OR 0.454) and mechanical intubation (OR 0.150) was observed. In patients hospitalized for COVID-19, the use of a prophylactic dosage of enoxaparin appears to be associated with similar in-hospital overall mortality compared to higher doses. These findings require confirmation in a randomized, controlled study