Effects of floaters on the free surface profiles of river flows

The presence of floaters should be taken into account when dealing with hydraulic analyses, e.g. when boats are moored along the river banks or large wood is expected to be conveyed by the river flow during floods. Many approaches have been proposed so far in order to consider the effects of floaters upon the flow features. Usually, they rely on the numerical resolution of the governing equation for both the fluid and the solid phases. Hence, their computational cost can be inadequate at the early stage of hydraulic studies or when large scale analyses have to be performed. A simplified method to compute the value of the resistance coefficient able to reproduce the effects of floaters upon the flow levels is proposed herein. The method is intended to provide the hydraulic parameters to be used within standard hydraulic simulations for which the effects of floaters must be accounted for; this is obtained by means of a modified resistance coefficient

Effects of the CPAP Treatment on the NON-REM Sleep Microstructures in Patients with Severe Apnea-Hypoapnea Syndrome

Sleep quality is affected in patients with sleep apnea- hypopnea syndrome (SAHS) with nocturnal and diurnal consequences. Most of these patients who are treated with positive airway pressure (CPAP) return to normal sleep patterns. We could consider good sleepers those patients who present more sleep spindles in stage II, and slower wave sleep as a good sign of better sleep quality. The objective in this research study was to compare the microstructure of stage II using the number of spindles and the increase of slow wave sleep before and after CPAP night titration. We developed a wavelet filter using a spline cubic function from a wavelet mother, which was appropriate to be used over electroencephalographic signal. By means of this filter in a multi-resolution mode, the spindles were detected from the increase of the IV band power; the sampling rate of the device determined the filter characteristics. The staging of polysomnographic studies was made by an expert according AASM (American Academy of Sleep Medicine) and then processed by the filter to get the index of sleep spindles before-and-after CPAP during stage II as well as the relationship between fast and slow powers from the EEG signal. An increase in the power of the slow waves vs. fast activity was observed in all the cases as a feature of better sleep. The neuroprotective effect described in previous research works regarding the density of the sleep spindles seems to be detected in patients improving their sleep quality after the correction of the apnea-hypopnea syndrome using CPAP.Fil: Smurra, Marcela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos Dr. Enrique Tornú; ArgentinaFil: Blanco, Susana Alicia Ana. Universidad de Belgrano. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Eguiguren, Veronica. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos Dr. Enrique Tornú; ArgentinaFil: Di Risio, Cecilia Diana. Universidad de Belgrano. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Feasibility of Tsunami Early Warning Systems for small volcanic islands

Abstract. This paper investigates the feasibility of Tsunami Early Warning Systems for small volcanic islands focusing on warning of waves generated by landslides at the coast of the island itself. The critical concern is if there is enough time to spread the alarm once the system has recognized that a tsunami has been generated. We use the results of a large scale physical model experiment in order to estimate the time that tsunamis take to travel around the island inundating the coast. We discuss how and where it is convenient to place instruments for the measurement of the waves

Groundwater Levels in a Drained Beach in Long and Short Waves Conditions

none5noneFischione, Piera; Pasquali, Davide; Di Nucci, Carmine; Di Risio, Marcello; Saponieri, AlessandraFischione, Piera; Pasquali, Davide; Di Nucci, Carmine; Di Risio, Marcello; Saponieri, Alessandr

Algorithms for Automatic, Real-Time Tsunami Detection in Sea Level Measurements

Automatic, real-time tsunami detection in sea-level measurements is a main component of a tsunami early warning system (TEWS). Although a great effort has been recently undertaken by the scientific and engineering community in developing new technologies (e.g. satellite altimetry, detectors of low-frequency elastic oscillations associated to a tsunami) capable of increasing the awareness of potential tsunamis in the minimum amount of time, at present direct detection in sea level measurements is still the main mean to confirm their actual generation and propagation, i.e. to upgrade or cancel the rapid initial warning usually given on the sole basis of seismic data. The paper describes the best available algorithms and numerical techniques which can be used for automatic real-time tsunami detection by using sea level measurements. The paper takes into consideration all possible device and locations for the sea level detection

Estimation of layer coefficients of cubipod homogeneous low-crested structures using physical and numerical model placement tests

[EN] Homogeneous low-crested structures (HLCSs) on hard seabed are designed to protect beaches and regenerate coral reefs. The height of a HLCS depends on the placement grid which determines the crest freeboard, wave transmission and concrete consumption. In real seafloor conditions, it is not easy to define feasible placement grids for HLCSs on uneven sea bottoms. In this study, the parameters of the numerical model Bullet Physics Engine (BPE) are calibrated and validated using the results of small-scale physical model placement tests of fivelayer Cubipod HLCSs on horizontal rigid bottom. The BPE model showed a low sensitivity to variations in the calibrated parameters; the numerical model estimated the layer coefficients with global mean relative errors of 1.04% and 1.39% in the triangular and rectangular placements grids, respectively. Once the numerical model was calibrated, new numerical and physical model tests on a 4% rigid bottom slope were compared for validation. A five-layer Cubipod HLCS on a 4% bottom slope was simulated using the BPE numerical model showing a global mean relative error of 2.75% compared to the small-scale physical model tests. A good agreement was found between numerical and physical model tests of five-layer Cubipod HLCSs on both horizontal as well as 4% rigid bottom slope. The BPE numerical model was found a suitable tool to estimate the structure height of HLCSs and to optimize placement grids of HLCSs on real cases with hard sea bottom.The authors thank the two anonymous reviewers for their constructive comments and suggestions, the financial support of the Spanish Ministerio de Ciencia, Innovacion y Universidades (Grant RTI 2018-101073-B-I00) and also Karel De Keyser and Elias Jacobs for conducting the physical placement test.Molines, J.; Centi, R.; Di Risio, M.; Medina, JR. (2021). Estimation of layer coefficients of cubipod homogeneous low-crested structures using physical and numerical model placement tests. Coastal Engineering. 168:1-11. https://doi.org/10.1016/j.coastaleng.2021.103901S11116

Engineering Tools for the Estimation of Dredging-Induced Sediment Resuspension and Coastal Environmental Management

In recent years, increasing attention has been paid to environmental impacts that may result from resuspension, sedimentation and increase in concentration of chemicals during dredging activities. Dredging dislodges and resuspends bottom sediments that are not captured by dredge-head movements. Resuspended sediments are advected far from the dredging site as a dredging plume and the increase in the suspended solid concentration (SSC) can strongly differ, in time and space, depending on site and operational conditions. Well-established international guidelines often include numerical modelling applications to support environmental studies related to dredging activities. Despite the attention that has been focused on this issue, there is a lack of verified predictive techniques of plume dynamics at progressive distances from the different dredging sources, as a function of the employed dredging techniques and work programs, i.e., spatial and temporal variation of resuspension source. This chapter illustrates predictive techniques to estimate the SSC arising from dredges with different mechanisms of sediment release and to assess the spatial and temporal variability of the resulting plume in estuarine and coastal areas. Predictive tools are aimed to support technical choices during planning and operational phases and to better plan the location and frequency of environmental monitoring activities during dredging execution

YPF en la era nacional y popular: Nueva ley de Soberanía Hidrocarburífera y nacionalización parcial de YPF: Un buen puntapié para iniciar el debate

La aprobación de la ley de Soberanía Hidrocarburífera, a principios de mayo, marca un avance frente al núcleo duro de políticas neoliberales que rigieron el sector durante dos décadas. La tan esperada medida de avance efectivo del Estado sobre el petróleo y el gas es una realidad. La recuperación del control y la gestión global del petróleo y el gas por parte del Estado nacional es un objetivo político-histórico de numerosas organizaciones. Sin embargo, las reformas implementadas -al menos en términos normativos- deberían constituirse en un nuevo piso sobre el cual avanzar y no en un punto de llegada.Fil: di Risio, Diego. Universidad de Buenos Aires. Facultad de Ciencias Sociales; ArgentinaFil: Pérez Roig, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Centro de Estudios e Investigación; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Sociales; Argentin