2,214 research outputs found
Laboratory Experiments on Long Waves Interacting with Rigid Vertical Cylinders
The impact of waves caused by storm surges or floods could lead to significant damage to marine and fluvial structures. Hydraulic forces add significant hydrodynamic loads on bridges built in coastal and fluvial environments; therefore, the effect of the wave impact on bridge substructures must be properly considered for the safe and cost-effective design of the piers. The use of laboratory-scale models is a direct approach to investigate the effects of long waves on simple structures, mimicking bridge piers. The present study describes a laboratory-scale model, where the propagation of two different long waves in a flume, in the presence of two rigid cylinders, was investigated. The velocity measurements were acquired by the Particle Image Velocimetry (PIV) technique, providing instantaneous flow velocity vectors on 2D planes. For each experimental condition, the instantaneous velocity field close to the cylinders was analysed, in order i) to depict how it changes during the wave transit, and thus how the drag force acting on the cylinders could change, ii) to detect the spatial distributions of vorticity downstream. Some first interesting results have been obtained, showing a quite uniform distribution of the longitudinal velocity along the depth of the vertical plane upstream of the cylinders, with increasing values during the wave transit. No interactions in the central part of the flow downstream of the two cylinders was observed in the horizontal plane which are spaced approximately ten times their diameter. Finally, the vorticity has also been studied, displaying a phase-varying behaviour, which appears to lose symmetry during wave transit
coastline evolution based on statistical analysis and modeling
Abstract. Wind, waves, tides, sediment supply, changes in relative
sea level and human activities strongly affect shorelines, which constantly
move in response to these processes, over a variety of timescales. Thus,
the implementation of sound coastal zone management strategies needs
reliable information on erosion and/or deposition processes. To suggest a
feasible way to provide this information is the main reason for this work. A
chain approach is proposed here, tested on a vulnerable coastal site located
along southern Italy, and based on the joint analysis of field data,
statistical tools and numerical modeling. Firstly, the coastline morphology
has been examined through interannual field data, such as aerial
photographs, plane-bathymetric surveys and seabed characterization. After this,
rates of shoreline changes have been quantified with a specific GIS tool.
The correlations among the historical positions of the shoreline have been
detected by statistical analysis and have been satisfactorily confirmed by
numerical modeling, in terms of recurrent erosion–accretion area and beach
rotation trends. Finally, based on field topographic, sediment, wave and
wind data, the response of the beach through numerical simulation has been
investigated in a forecasting perspective. The purpose of this study is to
provide a feasible, general and replicable chain approach, which could help
to thoroughly understand the dynamics of a coastal system, identify typical
and recurrent erosion–accretion processes, and predict possible future
trends, useful for planning of coastal activities
The water safety plan approach: Application to small drinking-water systems—case studies in salento (south italy)
none6noBackground: The quality of water for human consumption is an objective of fundamental importance for the defense of public health. Since the management of networks involves many problems of control and efficiency of distribution, the Water Safety Plan (WSP) was introduced to address these growing problems. Methods: WSP was applied to three companies in which the water resource assumes central importance: five water kiosks, a third-range vegetable processing company, and a residence and care institution. In drafting the plan, the terms and procedures designed and tested for the management of urban distribution systems were applied to safeguard the resource over time. Results: The case studies demonstrated the reliability of the application of the model even to small drinking-water systems, even though it involved a greater effort in analyzing the incoming water, the local intended use, and the possibilities for managing the containment of the dangers to which it is exposed. This approach demonstrates concrete effectiveness in identifying and mitigating the dangers of altering the quality of water. Conclusions: Thanks to the WSP applied to small drinking-water systems, we can move from management that is focused mainly on verifying the conformity of the finished product to the creation of a global risk assessment and management system that covers the entire water supply chain.openSerio F.; Martella L.; Imbriani G.; Idolo A.; Bagordo F.; De Donno A.Serio, F.; Martella, L.; Imbriani, G.; Idolo, A.; Bagordo, F.; De Donno, A
Kalman filter physical retrieval of surface emissivity and temperature from geostationary infrared radiances
The high temporal resolution of data acquisition
by geostationary satellites and their capability to resolve the diurnal cycle allows for the retrieval of a valuable source of information about geophysical parameters.
In this paper, we implement a Kalman filter approach to applying tempo-ral constraints on the retrieval of surface emissivity and temperature from radiance measurements made from geostationary platforms. Although we consider a case study in which we apply a strictly temporal constraint alone, the methodology will be presented in its general four-dimensional, i.e., space-time, setting.
The case study we consider is the retrieval of emissivity and surface temperature from SEVIRI
(Spinning Enhanced Visible and Infrared Imager) observations over a target area encompassing the Iberian Peninsula and northwestern Africa.
The retrievals are then compared with in situ data and other similar satellite products. Our findings show that the Kalman filter strategy can simultaneously retrieve surface emissivity and temperature with an accuracy of ± 0.005 and ±0.2 K, respectively
GPS Monitoring at Vesuvio, Campi Flegrei Caldera and Ischia Island (Southern Italy)
The Neapolitan volcanic area is located in the southern part of the Campanian plain and includes three active volcanoes (Vesuvius, Campi Flegrei Caldera and Ischia Island). This area shows different dynamical behaviours. Campi Flegrei caldera represents one well known and peculiar example of ground deformations (bradyseism), with periods of intense uplift during the 1969-72 and 1982-84, followed by subsidence phase with some episodic mini-uplifts superimposed. Contrary, Vesuvius is a substantially stable volcano, with small and localized subsidence mainly in the crater zone. Ischia Island has been characterized by subsidence in the S and NW sectors of the island. The presence of these three volcanoes in a dense populated area, makes ground deformation detection a crucial point in the risk mitigation. Ground deformation is an important volcanic precursor, because linked to magma overpressure and migration, thus, continuous monitoring and modelling is one of the main instruments to attempt for a short time forecast of eruptive activity. Since several years, the INGV – Osservatorio Vesuviano installed a permanent GPS network (NeVoCGPS), constituted of 27 stations, in the Neapolitan volcanic area with a configuration that guarantees a continuous and fast 3D information about the dynamics of the area. All the GPS stations are managed by remote control, the data are daily downloaded automatically. After an automatic quality control procedure, the data processing is performed by the Bernese Processing Engine (BPE) of the Bernese GPS software v. 5.0. In this work, the entire chain of data acquisition and processing is described and some results obtained in last years are presented
Somma Vesuvius volcano: ground deformations from CGPS observations (2001-2012)
This paper is a contribution to the evaluation of ground deformations at Somma-Vesuvius volcano by means GPS measurements from 2001 to 2012. In this study we use a dataset from nine continuous GPS stations
of the Neapolitan Volcanoes Continuous GPS network (NeVoCGPS), which covers the Neapolitan volcanic area, and is operated by the Istituto Nazionale di Geofisica e Vulcanologia. The GPS data processing is performed by the Bernese software v. 5.0. The results of the data processing show that the dynamics of the Somma-Vesuvio volcano, between 2001 and 2012, is characterized by a general subsidence, with maximum values
on the Gran Cono at BKNO (−11.7 ± 0.65 mm/year) and BKE1 (−4.92 ± 0.36 mm/year) stations. The subsidence decrease from the
crater down to the coast and the horizontal displacements are concentrated in Gran Cono area, the youngest part of the volcano. The parameters of the principal strain components indicate that Somma-Vesuvius is affected by a predominant contraction phase, which is concentrated in the areas with the greatest altitudes
The IASI Water Deficit Index to Monitor Vegetation Stress and Early Drying in Summer Heatwaves: An Application to Southern Italy
The boreal hemisphere has been experiencing increasing extreme hot and dry conditions over the past few decades, consistent with anthropogenic climate change. The continental extension of this phenomenon calls for tools and techniques capable of monitoring the global to regional scales. In this context, satellite data can satisfy the need for global coverage. The main objective we have addressed in the present paper is the capability of infrared satellite observations to monitor the vegetation stress due to increasing drought and heatwaves in summer. We have designed and implemented a new water deficit index (wdi) that exploits satellite observations in the infrared to retrieve humidity, air temperature, and surface temperature simultaneously. These three parameters are combined to provide the water deficit index. The index has been developed based on the Infrared Atmospheric Sounder Interferometer or IASI, which covers the infrared spectral range 645 to 2760 cm−1 with a sampling of 0.25 cm−1. The index has been used to study the 2017 heatwave, which hit continental Europe from May to October. In particular, we have examined southern Italy, where Mediterranean forests suffer from climate change. We have computed the index’s time series and show that it can be used to indicate the atmospheric background conditions associated with meteorological drought. We have also found a good agreement with soil moisture, which suggests that the persistence of an anomalously high water deficit index was an essential driver of the rapid development and evolution of the exceptionally severe 2017 droughts
AREA VULCANICA NAPOLETANA: 10 ANNI DI OSSERVAZIONI GPS
L’area napoletana è una delle zone a più alto rischio vulcanico, per la presenza di tre strutture vulcaniche attive (il Somma-Vesuvio, la caldera dei Campi Flegrei e l’Isola d’Ischia) e per l’intensa urbanizzazione della zona. La concentrazione dei suddetti vulcani attivi in un’area molto urbanizzata rende fondamentale la presenza di un sistema di monitoraggio che registri i fenomeni connessi al processo vulcanico in atto e che dia informazioni utili per modellarne il comportamento. Tra i vari fenomeni che generalmente sono associati ai processi vulcanici, le deformazioni statiche giocano un ruolo importante per lo studio dei parametri delle sorgenti magmatiche e per la loro modellazione. Nell’area vulcanica napoletana è presente una estesa rete GPS (sia permanente che discreta) che negli ultimi 10 anni ha permesso di raccogliere una mole importante di dati e di avere informazioni circa la dinamica in atto.
I dati raccolti in tale periodo, a causa dei rapidi sviluppi della tecnologia GPS, della strumentazione, delle metodologie di processamento, presentavano alcune disomogeneità nella qualità, nell’archiviazione e nell’elaborazione. Pertanto è stato necessario un notevole lavoro di verifica, correzione ed omogeneizzazione dal punto di vista qualitativo di tutti i dati disponibili. Successivamente si è potuto procedere al riprocessamento dei dati, utilizzando il software GPS Bernese v. 5.0, secondo i più recenti standard IGS.
Questo lavoro ha permesso di creare un database accurato di tutti i dati GPS disponibili per l’intera area vulcanica napoletana e il conseguente miglioramento della qualità dei risultati ha fornito un utile contributo all’interpretazione dei movimenti del suolo avvenuti negli ultimi anni. In particolare, i nuovi dati ottenuti hanno permesso un’accurata descrizione dell’andamento temporale dei modesti fenomeni di sollevamento (mini-uplift) che hanno interessato la caldera flegrea negli ultimi anni
Genomic changes of chromosomes 8p23.1 and 1q21: Novel mutations in malignant mesothelioma
Introduction: Malignant mesothelioma is an aggressive malignancy of the thoracic cavity caused by prior asbestos exposure. In the peritoneum the mesothelioma is an extremely rare condition. In the present preliminary study, high-resolution array-comparative genomic hybridization (a-CGH) was performed to identify genetic imbalances in a series of malignant peritoneal mesothelioma cases. Materials and methods: Between 1990 and 2008, among the cases recorded in the Apulia Mesothelioma Register, we found 22 peritoneal mesothelioma cases. CGH-array was performed on samples from all patients. Results: The CGH-array analysis revealed multiple chromosomal imbalances. Interestingly, deletion at 8p23.1 was observed in 12 cases. Furthermore, another novel deletion at 1q21 was present in 11. Often, 1q21 and 8p23.1 losses were present in the same patient (7 cases). Losses of BAP1 and CDKN2A loci were not detected. Discussion: The region at 8p23.1 contains the beta-defensin gene cluster (DEF) and 1q21 contains ubiquitin conjugating enzyme E2 (UBE2Q1). We hypotesized that the loss of function of ubiquitination, as well as of the defensins, could play an important role in the initial development and subsequent progression of mesothelioma
Salmonella enterica Control in Stick Carrots Through Incorporation of Coriander Seeds Essential Oil in Sustainable Washing Treatments
Chemical disinfectants represent one of the commonly used practice in minimally processed vegetables food-chain. However, the scarce safety and sustainability of these agents force food industry to move toward more sustainable “green washing solutions.” Among the latter, while the application of plant derivates for the control of several pathogens is already well-known, the potential anti-Salmonella activity of Coriandrum sativum seeds derivates is still unexplored and was therefore investigated in this study. In detail, Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of different coriander seed derivates (i.e., essential oil, hydrosol, and ethanolic extract) were determined by broth dilution against six Salmonella enterica strains isolated from fresh and minimally processed fruits and vegetables. Only the essential oil (EO) was effective in vitro with strain-dependent results. In addition, when mixed in co-culture, the strains were more sensitive to the essential oil treatment. Chemical investigations allowed to define (s)-(+)-linalool as major compound in the essential oil, and to underline interesting phenolic content with correlated antioxidant capacity. A cocktail of three strains of different serovars was selected and employed for a preliminary in situ trial on stick carrots. The obtained results allowed to establish that the application of coriander seed EO at concentrations of 5 μL mL−1 was able to reduce and contain the growth of the Salmonella cocktail up to 24 h at 10°C. Good sensory evaluation results were obtained by applying this EO concentration as washing treatment, especially in terms of color parameter. Further studies should be undertaken to emphasize the upstream activity, improving the formulation or exploiting a combined effect with other sanitizers or treatments (e.g., physical treatments). The present study contributes to the knowledge on coriander derivates activity against Salmonella spp. and on the potential application as sustainable washing treatment in removing this pathogen from fresh cut carrots
- …