Riviste Online SApienza - R.O.SA - 2 (Sapienza University of Rome)
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Physical model tests on spar buoy for offshore floating wind energy converion
Get PDFThe present paper describes the experiences gained from the design methodology and operation of a 3D physical model experiment aimed to investigate the dynamic behaviour of a spar buoy floating offshore wind turbine. The physical model consists in a Froude-scaled NREL 5MW reference wind turbine (RWT) supported on the OC3-Hywind floating platform. Experimental tests have been performed at Danish Hydraulic Institute (DHI) offshore wave basin within the European Union-Hydralab+ Initiative, in April 2019. The floating wind turbine model has been subjected to a combination of regular and irregular wave attacks and different wind loads. Measurements of displacements, rotations, accelerations, forces response of the floating model and at the mooring lines have been carried out. First, free decay tests have been analysed to obtain the natural frequency and the modal damping ratios of each degree of freedom governing the offshore. Then, the results concerning regular waves, with orthogonal incidence to the structure, are presented. The results show that most of longitudinal dynamic response occurs at the wave frequency and most of lateral dynamic response occurs at rigid-body frequencies
A synthetic air pollution index using a T2 approach
Get PDFIt is generally acknowledged that exceedance of the safe thresholds of air pollutants significantly affect human health. Hence, we can understand the importance of having a synthetic measure for overall air pollution, in a certain geographical area, computable using an index: to the values taken on by this index are then associated different health risks. In order to compute a reliable and comparable air quality index, in this paper we suggest an analytical procedure based on data reduction functions for summarizing three-way arrays, here consisting of the observations on a few major pollutants monitored over time at multiple sites. These functions reduce the dimensions of the array by applying a joint principal component analysis. Symmetrical three-way PCA has been successfully applied in environmental experimental studies, where the three dimensions of the data array are typically of similar length. Instead, a long time dimension usually characterizes environmental pollution data, where an asymmetrical twoway PCA is preferable: the aim of this paper is to indicate an approach that, by reducing two of the three dimensions, leads to the computation of an informative air quality index. Plaia et al. (2013) have applied an analogous approach, but reducing just one dimension of the array
Seismic hazard analysis of Zarand city using ahp-gis
Get PDFThis paper presents a detailed study about the seismic pattern of Zarand County in Kerman province that is an area with a high risk of earthquakes in Iran. The population of the Zarand County is about 120000. There are numerous active faults in the region and the area has been hit by several strong earthquakes, two of which were most deadly during the last half-century.In this research, the seismotectonics and seismic hazard was evaluated by probabilistic and analytical methods in 1:100000 scale geological map of the Zarand. Seismic risk analysis using the Gutenberg-Richter law predicted the probability for an earthquake with a magnitude of 6.5 on the Richter scale in the area within the next 40 years, 100 percent. Based on the results, Zarand City is considered as a medium and high earthquake risk area. The highest percentage of earthquake hazard is located in the central and north and northeastern regions of Zarand\u27s geological map. In this map, the area with a high risk and very high risk is 35.43% and 24.22% respectively
Coastal erosion mitigation through ejector devices application
Get PDFTo mitigate coastal erosion and harbors siltation, new strategies are required in the immediate term. In fact, even if many traditional solutions are available, their application is usually limited due to economic, environmental and social reasons. This situation is particularly evident in the case of small marinas or in those areas where the local economy is strongly affected by harbor operation such as in the case of the port of the municipality of Cervia (Italy). To solve the problem occurred in this specific case, an innovative device, called the “ejector”, is proposed and implemented in a dedicated experimental plant characterized by low operative costs and no environmental impact. Starting from the description of the technology, the paper aims to show the ejector’s potentials with respect to siltation and erosion problems. For the purpose the first results derived from the application in the case study at the municipality of Cervia are reported
A new cave dwelling Duvalius from the Aurunci Mountains (Lazio) (Coleoptera: Carabidae)
Get PDFA new anophthalmic carabid beetle belonging to the genus Duvalius Delarouzée, 1859, recently collected in a deep cave in the Southern Aurunci Mountains, Lazio, is described. The new species appears to be the most troglomorphic among all the thus far known Italian Duvalius
Xanthochroina Ganglbauer, 1881, a new genus of Oedemeridae for the Italian fauna (Coleoptera)
Get PDFIn this paper is reported for the first time with certainty the presence in Italy of the genus Xanthochroina, exhibiting a Holarctic discontinuous distribution. The Mediterranean species X. auberti is recorded from western Liguria and information on the range of the species is updated
Expanding the European distribution limits of Bruchidius raddianae. First record in Portugal from Vachellia karroo’s infested seeds (Coleoptera: Bruchidae; Fabales: Fabaceae)
Get PDFSeveral Australian and African Acacia shrubs and trees have been intentionally introduced into the Mediterranean basin for different purposes, but some species become invasive, such as Vachellia karroo (Hayne) Banfi and Galasso (syn. Acacia karroo) (Fabales: Fabaceae). The seed beetles, belonging to family Bruchidae, have a significant ecological and economic importance, either because they can be plant pests or, on the other hand, be used as biocontrol agents against invasive plant species. Bruchidius raddianae (Anton and Delobel, 2003) (Coleoptera: Bruchidae) is native to tropical and subtropical areas, but it has been recently reported from Cádiz and Málaga (southern Spain, 2007) and in the Lampedusa Island (Italy, 2015) from seeds of pods collected from V. karroo. This paper reports 104 specimens reared from seeds collected from V. karroo in Faro (southern Portugal) from August to October 2019, expanding the B. raddianae’ European distribution limits. This is also the first report of its presence in Portugal and the third in Europe
Four peculiar new Metallactus species from Argentina (Coleoptera: Chrysomelidae, Cryptocephalinae)
Get PDFMetallactus canescens sp. nov., Metallactus aemulus sp. nov., Metallactus diaguita sp. nov., Metallactus nugator sp. nov. are described from Northern and Central Argentina. The new species are very similar to one another regarding their external look but can be distinguished above all on the basis of internal characters, in particular the morphology of the aedeagal median lobe. Besides, some traits of their external features, i. e. the thick dorsal setosity and the weak metallic hue, look quite uncommon within the genus Metallactus Suffrian, 1866 and remind of some species of genus Coscinoptera Lacordaire, 1848 (in particular C. tibialis Harold, 1875) and other undescribed species belonging to the genus Griburius Haldeman, 1849. This might be due to some kind of adaptive convergent evolution
Coastal vulnerability assessment through complementary monitoring technologies: the case of Riccione
Get PDFMonitoring is known to be the basis for coastal planningand management studies, for verifying the interventions effects and for forecasting the future state of beaches. There are several proxies that must be considered in the definition of a monitoring plan, such as the spatial and temporal extension of the monitoring activities, the types of data and their required accuracy values, the acquisition frequency of the data and perhaps the available budget to invest are among the most important aspects. The present paper presents the first results of the monitoring activity with integrated and complementary techniques applied to a stretch of coast near the city of Riccione, North Italy, within the framework of the research project STIMARE, financed by the MATTM and of the project POR FESR TAO. The site is protected by non-traditional defense works, and the on-going activities aim to monitor the shoreline evolution by using videocameras, with a low-cost hardware system, based on Raspberry Pi components, and the development of on-site software for the survey, correction and georeferencing of data. The monitoring of the emergence and submerged beach is carried out by means of topographic and bathymetric surveys (terrestrial laser scanner, UAV photogrammetry, ASV multibeam), allowing a very high-resolution digital terrain model (DTM) to be obtained. The comparison between successive surveys acquired with different techniques provides information on the response of the coastal stretch to the local regime of waves and currents and on the effects of the defense structures on the seabed, both in the nearfield and in the farfield, with the possibility of quantifying the volumes of eroded or accumulated sand. Finally, the two monitoring approaches are shown to be complementary in terms of time and precision: direct surveys provide data with high spatial precision but not continuous acquisition due to budget and logistics reasons, while video monitoring provides only information on the shoreline, (used as a proxy for the description of coastal dynamics) but with data continuously acquired. The project aims to verify the complementarity and integration of the different techniques adopted in monitoring, and the possible feasibility in other coastal stretches with the purpose of assessing vulnerability
The praying mantises of the Maltese Islands: distribution and ecology (Mantodea)
Get PDFThis study presents a species account of the mantises of the Maltese Islands, including notes on the ecology and distribution of each species. A total of three species are known to exist locally; Ameles spallanzania (Rossi, 1792), Mantis religiosa (Linnaeus, 1758) and Rivetina baetica Rambur, 1839. The presence of Ameles decolor (Charpentier, 1825) cannot be confirmed by any recently collected material, but the species is not excluded from the Maltese entomofauna. Two doubtful records are also discussed. All species present in the archipelago are typically found in Southern Europe and the Mediterranean basin