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The paper shows that a Finite Volume method with an HLL Riemann solver may incorrectly reproduce the depth-averaged velocity under uniform flow in a channel with non-rectangular cross section. A specific treatment for evaluating the fluxes at the sides has been proposed and tested.

In the present paper the mathematical character of the two-phase depth-averaged morphodynamical model proposed by Di Cristo et. al (2014) is discussed. In particular, in this model the bed-load concentration is dynamically evaluated provided that an algebraic expression for bed-load thickness is assumed. To this aim, some adaptations of empirical correlations proposed for uniform equilibrium flow conditions may be considered, modifying the differential structure of the problem. In this paper the model eigenstructure is studied considering thee different expressions of the bed-load thickness, showing that the mathematical character of the model is significantly affected by the adopted relationship. In particular, when relationships accounting for only the bed-load volume for unit bottom area or both the solid phase velocity and the bed-load volume for unit bottom surface are considered the model is hyperbolic. In contrast, a hyperbolicity loss is detected for the expression which accounts for only the liquid velocity. The domains of nonhyperbolicity are individuated in terms of the relevant dimensionless parameters and represented through shaded maps. The results of the analysis aim to guide the users to define the correct number of boundary conditions and to choose the most appropriate numerical solver in simulating fast geomorphic transients.

Il presente volume digitale ad accesso libero (licenza Creative Commons 4.0) raccoglie le memorie brevi pervenute al Comitato Scientifico di IDRA16 ed accettate per la presentazione al convegno a valle di un processo di revisione tra pari. Il volume articola dette memorie in sette macro-tematiche, che costituiscono i capitoli del volume stesso: I. meccanica dei fluidi; II. ambiente marittimo e costiero; III. criteri, metodi e modelli per l’analisi dei processi idrologici e la gestione delle acque; IV. gestione e tutela dei corpi idrici e degli ecosistemi; V. valutazione e mitigazione del rischio idrologico e idraulico; VI. dinamiche acqua-società: sviluppo sostenibile e gestione del territorio; VII. monitoraggio, open-data e software libero. Ciascuna macro-tematica raggruppa più sessioni specialistiche autonome sviluppatesi in parallelo durante le giornate del Convegno, i cui titoli vengono richiamati all’interno del presente volume. La vastità e la diversità delle tematiche affrontate, che ben rappresentano la complessità delle numerose sfide dell’Ingegneria delle Acque, appaiono evidenti dalla consultazione dell’insieme di memorie brevi presentate.

Disinfection of drinking water is usually achieved by means of chlorine compounds for their effectiveness and low cost. They ensure a residual concentration in the water supply system (WSS), which reduces the risk of pathogenic contamination and limits the proliferation of microbial species. However, chlorine reacts with the organic matter in the water producing disinfection byproducts (DBPs). Some DBPs, such as trihalomethanes (THMs) have carci nogenic effects on human health and then their concentration has to be monitored and maintained below fixed values. In this context, the objective of present paper is to show a procedure for performing a vulnerability analysis respect elevated THMs exposure in WSS. The introduction of specific index parameters allows to identify the more critical nodes of the system respect to different kind of exposure, high concentration exposure for a short period or chronic exposure to low THMs concentrations, which are both important for epidemiological studies. The analysis is applied to the real water distribution system of Cimitile, a town in South Italy, in which water is disinfected through sodium hypochlorite. The results show that the considered parameters identify different vulnerable nodes respect to the different kind of exposure. The presented procedure may be also useful for implementing methodologies for the optimization of the chlorination process in water supply systems.

For unsteady flow problems, such as propagation of flood waves in open channels, simplified models, know as kinematic, diffusion and quasi-steady, are widely used instead of solving the full dynamic model. In order to correctly use these models, it is mandatory to define the conditions in which they may be applied. The present paper investigate the applicability conditions of the kinematic, diffusion and quasi-steady dynamic shallow wave models for mud flows, modeled as a power law fluid. In the framework of a linear analysis, the applicability ranges are defined by comparing the propagation characteristics of a sinusoidal perturbation to the initial steady uniform flow predicted by the simplified models with those of the full dynamic one. The present results provide guidelines for selecting an appropriate approximation for modeling unsteady power law fluid flow problems and they may represent a useful tool for engineering predictions.

https://doi.org/10.1061/(ASCE)HY.1943-7900.0000538

Chlorination is the most widely used method for disinfection of drinking water, being very effective and relative inexpensive. However there are concerns about the formation of chlorination by-product, such as trihalomethanes (THMs), since the chronic exposure to them may pose risks to human health. For striking a balance between protection from microbiological risks and the risks connected to byproducts, it is necessary to maintain throughout the distribution system free chlorine residual above a minimum value and the THMs concentration below a maximum level. For these reasons it is very important to be able to correctly reproduce THMs formation in water distribution systems. In literature many models for predicting THMs formation, based on empirical relationships, have been proposed. In this work 18 literature empirical models have been selected for investigating their reliability in real situations through the application to a real water supply system in Southern Lazio (Italy). The comparison of the performances of such models furnishes interesting observations. The predictions of the empirical models are also compared with the results obtained using a simple first order kinetic model, calibrated using measured data.

La disinfezione delle acque comporta, di norma, la formazione di sottoprodotti che possono avere effetti negativi sulla salute. Per tale motivo la Normativa vigente in Italia impone per le acque potabili delle soglie massime di concentrazione di tali prodotti da rispettare alla consegna all’utenza. D’altro canto il trattamento di disinfezione deve assicurare la presenza di concentrazioni minime di disinfettante residuo. Il rispetto contemporaneo di tali limiti necessita della conoscenza delle cinetiche di decadimento del disinfettante e di formazione dei sottoprodotti. Lo scopo del presente lavoro è quello di fornire un contributo a tale conoscenza, presentando la costruzione di un modello idraulico e di qualità per il sistema acquedottistico degli Aurunci–Valcanneto in provincia di Frosinone. La calibrazione del modello di qualità, effettuata usando numerose misure di campo, consente considerazioni sul tipo di cinetica da utilizzare e sui valori da assegnare alle costanti.

We demonstrate that Oct-ER is localized in the vertical superior frontal system and binds Estradiol with high affinity.

Nel presente contributo si analizza l’effetto della variabilità del coefficiente di resistenza sulla crescita delle roll-waves nella fase iniziale della loro formazione. Lo sviluppo delle roll-waves viene analizzato schematizzando il fenomeno come l’evoluzione di un perturbazione sia istantanea sia pulsante nel tempo con frequenza assegnata. In entrambi i casi l’influenza della variabilità dell’indice di resistenza dalle variabili idrodinamiche risulta essere rilevante. I risultati ottenuti con i due schemi sono poi confrontati con quelli di un modello numerico 1D alle acque basse.

This arrangement provides a temporal filter for visual processing and enhances perception of moving vs stationary object.

We recently reported the molecular cloning of nitric oxide synthase (NOS) mRNA from Sepia officinalis (SoNOS) using a strategy that involves hybridization of degenerate PCR primers to highly conserved NOS regions, combined with a RACE procedure. Here, in situ hybridization study has been performed on serial sections of the cuttlefish central nervous system to reveal localized specific staining of cell bodies in several lobes of the brain. Staining was found in many lower motor centres, including cells of the inferior and superior buccal lobes (feeding centres); in some higher motor centres (anterior basal and peduncle lobes); in learning centres (vertical, subvertical and superior frontal lobes); and in the visual system [medulla and deep retina (optic lobe)]. Positive staining was also found in the olfactory lobe. NOS-expressing cells have been detected also in the interbasal lobe. Double labelling experiments, performed on consecutive sections, showed that neurons containing NOS immunoreactivity were also positive in in situ hybridization staining. All these data support the presence of NOS in several systems in the cuttlefish brain.

In the paper a linear stability analysis of a one–dimensional morphodynamical model is presented. The local equilibrium assumption on the solid discharge is removed and a dynamical description of the bed–load transport is employed. Both unsteady and quasi–steady flow models are analysed and discussed. The results reveal the existence, at moderate Froude number values, of perturbations related to bed elevation instability, migrating in the upstream direction both in quasi–steady and full unsteady models.

The quality of drinking water is a great concern in many countries and recently many researches have focused their attention to improve drinking water security threatened by deliberate or accidental injection in water distribution systems. A very important aspect is the identification of the point in which the pollutant goes into the network, but this problem has not yet been addressed extensively. The authors propose a methodology able to identify pollution source location in a water distribution network, if consumers or sensor stations detect that a contamination is in act. The methodology is based on a pathway analysis of the network and on the demand coverage concept.!n a first step, a subset of candidate nodes that may be potential source of pollution is individuated. Then, using concentration measurements the source is identified among all candidate nodes solving a linearized optimization problem, which incorporates a hydraulic network simulation model. The analysis is performed on the period during which water quality measurements are available and for which a demand pattern is assigned. Since demand patterns can be estimated only with a high level of uncertainty, only source identification procedures, robust respect to such uncertainty, could be applied to real networks.!n order to demonstrate the practical applicability of the proposed methodology to real situations a Montecarlo analysis is performed for considering nodal demand uncertainty. The uncertainty analysis is performed both in case of constant and time-varying pollutant input concentration. The results show that in both cases the proposed source identification procedure has a good reliability even at high water demand uncertainty levels.