Search results for "ground"
showing 10 items of 2432 documents
Uso del nocciolino di oliva come materiale di riempimento di biotrincee per la denitrificazione biologica in situ di acque di falda
2016
Tra le varie possibilità di intervento per la rimozione dei nitrati dalle acque di falda, notevole interesse suscita il trattamento in situ dei plume contaminati mediante la realizzazione di biotrincee denitrificanti scavate in situ e naturalmente attraversate dalle acque di falda. Tra i materiali di origine organica che sono stati testati per tali applicazioni, il nocciolino di olive è risultato uno dei più idonei alle potenziali applicazioni di pieno campo. Tale tipo di materiale possiede un elevato contenuto di carbonio organico totale, prossimo al 50%, e una percentuale di lignina prossima al 45% in peso. Il lavoro proposto riporta i risultati di una campagna sperimentale eseguita media…
La denitrificazione biologica delle acque di falda: studio di tre differenti substrati organici
2015
L’uso massiccio di fertilizzanti contenenti azoto è causa dei fenomeni di inquinamento diffuso delle acque di falda. In tale ottica, notevole interesse hanno recentemente riscosso i trattamenti biologici in situ, in grado di promuovere la denitrificazione delle acque di falda mediante la realizzazione di interventi che coniugano efficacia di rimozione e costi relativamente contenuti. Nella nota si riportano i risultati di una ricerca sul processo di denitrificazione eterotrofa, condotta utilizzando come fonte di carbonio tre materiali convenzionalmente considerati di scarto: corteccia di pino, sughero e sansa di olive. Lo studio è stato suddiviso in due fasi: la prima condotta in modalità b…
Life cycle environmental assessment of retaining walls in unsaturated soils
2022
Abstract Retaining structures above groundwater level support soils that are usually in a state of partial saturation and subject to the actions of atmospheric agents. The current design approach considers the possible extremes of soil conditions – either totally dry or totally saturated – but it neglects matric suction’s contribution to soil shear strength. This work aims to describe how unsaturated-soil mechanics of can positively influence the sustainability of retaining structures through a holistic, multidisciplinary, geotechnical, and environmental analysis. The geotechnical analysis allows to estimate the lateral earth pressure of a geostructure in both unsaturated and extreme soil c…
The Effects of Structure on the One Dimensional Compression Behaviour of a Porous Calcarenite
2019
Human settlements built on weak rock deposits are often characterized by instabilities or collapse that may involve the underground cavities and consequently the above buildings. Underground calcarenite quarries in Marsala have been involved in a number of collapses that have seriously damaged numerous buildings. Unfortunately proper engineering solutions have not yet been identified according to the different and special cases and to the properties of this structured material. In order to investigate structure effects on the behaviour of the porous calcarenite of Marsala, this paper presents a comparison between the one dimensional compression behaviour of the intact rock and of the same w…
Nonlinear Response of RC Structures: Statistical Effects of Artificial Ground Motions
2020
The selection of seismic inputs for nonlinear dynamic analysis is widely debated, mainly focusing on the advantages and disadvantages provided by the choice of natural, simulated or artificial records. However, most of the available technical codes do not provide always the same suggestions and well-defined procedures for the generation of artificial ground motions. Considering that the strategy of the generation of accelerograms makes some doubts raise about the possible effect on the structural response, the work aims to investigate on the differences of the structural behavior by using accelerograms nominally equivalent but different in terms of stationarity. This paper presents a compar…
Proposal of a Selection Criterium of Natural Accelerograms for NLRHA
2014
A selection criterion to obtain different sets of accelerograms, all of them satisfying the spectrum compatibility criteria imposed by the codes, that enable a reliable assessment of the seismic demand for a given structure is proposed. The formulation is based on a preliminary evaluation of correlations among Intensity Measure parameters for ground motion and cinematic, energetic and damage parameters describing structure non linear responses. To this aim, a modified expression of the Effective Peak Acceleration EPA* is proposed, defined over the range of structure fundamental period referring to undamaged and damaged model. The analyses are carried out analyzing the response of a three pl…
Il sistema cava-concimaia nella Fossa della Garofala a Palermo
2020
During the 60s and 70s of the 20th century, the widespread construction of new buildings in the agricultural areas around the city centre of Palermo have changed the original landscape. A rare exception is represented by an area called Fossa della Garofala; in this place the topic of “stratification” creates a connection between the geological history and the most recent anthropogenic interventions. Here, one of the places of greatest interest where the signs of a very distant past and a very recent past gather and the epigeal and hypogeal dimensions are put in an immediate relationship is certainly the original system consisting of a quarry and a so called concimaia. If on one hand, the co…
ARCHITETTURE PER LE ACQUE SOTTERRANEE. CONSERVAZIONE E VALORIZZAZIONE DEL PATRIMONIO CAVO A PALERMO
2019
The valorisation policies and protection of “visible” architectural heritage are often promoted by the public opinion, that immediately perceives in the artefacts degradation the risk of an irreparable loss. Conversely, the safeguard of the underground built heritage is ever more difficult to achieve. It is the case of the "hollow architecture" functional to ensuring water provisioning in the Piana di Palermo: “horizontal wells” and “qanat”. These artefacts date back to the sixteenth century, though an older dating is not to be excluded. The need for studies on underground historical construction is more evident if we consider the scarcity of documentary material and specialised literature.…
Giuseppe Samonà e la “spina dorsale” di Gibellina Nuova
2020
Nel 1970 Giuseppe Samonà coordina il gruppo di progettazione formato da Vittorio Gregotti, Gianni Pirrone e Alberto Samonà per il Progetto del Centro civico, commerciale e culturale di Gibellina Nuova. Del piano è realizzato il municipio e poi, rielaborato e in altro luogo, il teatro. I monumenti, fondati su un asse pedonale in quota connesso a un suolo artificiale articolato, esprimono l’unità architettura – urbanistica e anticipano, per certi versi, una riflessione successiva del Direttore dello IUAV sulla dialettica fra urbano e rurale.
A NON CONVENTIONAL UAV IN GROUND EFFECT: ESTIMATION OF STATE AND TURBULENCE VIA EXTENDED KALMAN FILTER
2009
ABSTRACT This paper discusses the synthesis of an Extended Kalman Filter (EKF) to perform both wind velocities and state estimation for a non conventional UAV flying in ground effect. Since, in IGE flight, motions into the symmetry plane are of primary concern, the study focuses on the longitudinal aircraft dynamics. The proposed estimator requires measurement of few flight variables, easily obtainable by means of conventional sensors; besides, it does not use Inertial Measurement Unit (IMU). To simulate a low cost sensing equipment, the model outputs are corrupted by white noise of relatively high standard deviation. Furthermore, to cope with the low rate of the GPS with respect to the oth…