Numerical and Physical Modeling of Ponte Liscione (Guardialfiera, Molise) Dam Spillways and Stilling Basin

Issues such as the design or reauditing of dams due to the occurrence of extreme events caused by climatic change are mandatory to address to ensure the safety of territories. These topics may be tackled numerically with Computational Fluid Dynamics and experimentally with physical models. This paper describes the 1:60 Froude-scaled numerical model of the Liscione (Guardialfiera, Molise, Italy) dam spillway and the downstream stilling basin. The k-omega SST turbulence model was chosen to close the Reynolds-averaged Navier-Stokes equations (RANS) implemented in the commercial software Ansys Fluent(R). The computation domain was discretized using a grid with hexagonal meshes. Experimental data for model validation were gathered from the 1:60 scale physical model of the Liscione dam spillways and the downstream riverbed of the Biferno river built at the Laboratory of Hydraulic and Maritime Constructions of the Sapienza University of Rome. The model was scaled according to the Froude number and fully developed turbulent flow conditions were reproduced at the model scale (Re > 10,000). From the analysis of the results of both the physical and the numerical models, it is clear that the stilling basin is undersized and therefore insufficient to manage the energy content of the fluid output to the river, with a significant impact on the erodible downstream river bottom in terms of scour depths. Furthermore, the numerical model showed that a less vigorous jet-like flow is obtained by removing one of the sills the dam is supplied with

Improvement in workability of terminals placed along the inner side of port vertical breakwaters by means of recurved parapet walls

The function of main port breakwaters is to protect harbour basins from incoming waves and currents. In the event that a maritime terminal is placed on the inner side of a main breakwater, it is extremely important to limit waves overtopping the structure, because the overtopping flows may be very dangerous for the safety of the operations taking place in the terminal. Very often during storms if the overtopping discharges are severe, the terminal is temporarily closed, reducing its average annual workability accordingly. Wave overtopping is normally limited by using high parapet walls (crownwalls) which are not well considered from an environmental point of view due to their visual impact. A good solution to reduce wave overtopping limiting the increasing of the crownwalls height, is to use recurved parapet walls. The paper presents a new formula for recurved walls which can be used to estimate the overtopping flow rates reduction compared to normal vertical parapets. The formula has been obtained for vertical breakwaters by using numerical computations. The recurved parapet has the shape of a circumference sector, characterized by a radius and an opening angle. The numerical computations were performed applying OpenFOAM® which solves the 3D RANS equations for multiphase flows (air and water). The results show the high hydraulic efficiency of recurved walls in reducing overtopping rates compared to traditional vertical parapets

Neuropsychiatric systemic lupus erythematosus: where are we now?

When dealing with neuropsychiatric Systemic Lupus Erythematosus (NPSLE) there are still many controversial topics. In 1999 the American College of Rheumatology gave classification criteria for 19 clinical syndromes. However major problems are still related to low specificity of some of them such as headache, cognitive impairment or mood disorders. Even though a frequency of CNS involvement from 14 to 75% has been described, depending on both the population studied and the methodology of assessment, a lower frequency ranging from 21 to 28 % derived by larger case series seems more realistic. The introduction of the concept of "borderline cases", proposed by Italian Study Group for NP-SLE, is based both on clinical and instrumental evaluation and could represent a useful tool when dealing with conditions which do not fulfil ACR classification. Also the relationship between SLE activity and NP involvement is a debated issue. Concerning pathogenesis, it seems reasonable to consider multifactorial mechanisms related to antibody-mediated damage, antiphospholipid pro-thrombotic effect, non-inflammatory vasculopathy and cytokines mediated cytotoxycity. However, direct and unequivocal evidence for the implication of any of the above-mentioned mechanisms is still lacking. Although a wide range of neuroimaging tools have been used to evaluate CNS involvement, no single technique has proven to be definitive and, when dealing with a patient with suspected NPSLE, it is important to combine different diagnostic techniques. Due to the lack of effective imaging along with limitation in knowledge of underlying pathogenetic mechanisms and paucity of histopathologic findings, therapeutic approach in NPSLE remains a difficult issue and is currently based on personal experience. Italian Study Group for NP-SLE proposes the creation of a national registry on NPSLE to validate ACR classification criteria. Furthermore, the possibility to collect large series and stratifying them for each of the included neuro-psychiatric syndromes seems a good strategy for planning multicentric controlled therapeutic trials in the near future

Lead-free piezoelectrics: V3+ to V5+ ion conversion promoting the performances of V-doped Zinc Oxide

Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as-grown thin films or after a post-deposition rapid thermal annealing (RTA) treatment performed at 600 °C for different lengths of time (1 and 5 min) in an oxygen atmosphere. Substitutional doping of Zn2+ with V3+ and V5+ ions strongly deteriorated the hexagonal wurtzite ZnO structure of the as-grown thin films due to lattice distortion. The resulting slight amorphization led to a poor piezoelectric response and higher resistivity. After the RTA treatment, strong c-axis oriented VZO thin films were obtained, together with a partial conversion of the starting V3+ ions into V5+. The improvement of the crystal structure and the stronger polarity of both V3+ – O and V5+ – O chemical bonds, together with the corresponding easier rotation under the application of an external electric field, positively affected the piezoelectric response and increased conductivity. This was confirmed by closed-loop butterfly piezoelectric curves, by a maximum d33 piezoelectric coefficient of 85 pm·V−1, and also by ferroelectric switching domains with a well-defined polarization hysteresis curve, featuring a residual polarization of 12.5 μC∙cm−2

Standardization of Cu2O nanocubes synthesis: Role of precipitation process parameters on physico-chemical and photo-electrocatalytic properties

A facile, reproducible, and scalable wet precipitation method was optimized to synthetise Cu2O nanocubes with tuneable morphology and photocatalytic properties. The synthesis process was standardized by controlling the flow rate of addition of the reducing agent. This allowed to control the Cu2O crystallites size, which decreased from 60 nm to 30 nm by increasing the L-ascorbic acid flow rate, while maintaining a high yield (ranging from 87% to 97%) and reproducibility, as confirmed by X-Ray diffraction, scanning electron microscopy, and X-Ray photoelectron spectroscopy analyses. Moreover, the role of the synthesis conditions on the Cu2O nanocubes specific surface area and electrochemical surface area (ECSA) were investigated and correlated to their photo-electrocatalytic activity for the reduction of water and CO2 under ambient conditions, on electrodes made by air brushing. Decreasing of the Cu2O crystallites size enhanced the photo-electrocatalytic activity most probably due to a superior surface area, ECSA and an optimum valence and conduction band positions, which improves the charge transfer properties of the photocatalyst. The here proposed methodology and outcomes are very promising for the scale-up of the precipitation synthesis, not only of Cu2O but also of other nanostructured metal oxides to be exploited as photo-catalysts for environmental and energy applications

Li+ Insertion in Nanostructured TiO2 for Energy Storage

Nanostructured materials possess unique physical-chemical characteristics and have attracted much attention, among others, in the field of energy conversion and storage devices, for the possibility to exploit both their bulk and surface properties, enabling enhanced electron and ion transport, fast diffusion of electrolytes, and consequently high efficiency in the electrochemical processes. In particular, titanium dioxide received great attention, both in the form of amorphous or crystalline material for these applications, due to the large variety of nanostructures in which it can be obtained. In this paper, a comparison of the performance of titanium dioxide prepared through the oxidation of Ti foils in hydrogen peroxide is reported. In particular, two thermal treatments have been compared. One, at 150 °C in Ar, which serves to remove the residual hydrogen peroxide, and the second, at 450 °C in air. The material, after the treatment at 150 °C, results to be not stoichiometric and amorphous, while the treatment at 450 °C provide TiO2 in the anatase form. It turns out that not-stoichiometric TiO2 results to be a highly stable material, being a promising candidate for applications as high power Li-ion batteries, while the anatase TiO2 shows lower cyclability, but it is still promising for energy-storage devices