371 research outputs found
Tracking Results in Agriculture and Rural Development in Developed Countries: Methodological Issues on a National Accounts Prospective
Monitoring and Evaluation of policies is intrinsically challenging and requires a very high level of technical capacity. Appropriate statistical indicators have to be selected and calculated to satisfy the needs of final users, linking the date to statistical demand. Appropriate classifications and definitions are also essential, while different data-sources and highly disaggregated estimations are needed; for instance, for small areas estimations and rural areas. Furthermore, Evaluation of a policy is a specific purpose, different from monitoring a project or long run economic analysis. The paper try to address the argument from a National Account prospective, rely on the assumption that this is an appropriate macro-economic framework for statistics and to base scientific studies.National Accounts, Monitoring&Evaluation, Agriculture, Rural Development Statistics, Agricultural Households Income, Agricultural and Food Policy, E01,
Investigation of sloshing effects on flexible aircraft stability and response
The present paper provides an investigation of the effects of linear slosh dynamics on aeroelastic stability and response of flying wing configuration. The proposal of this work is to use reduced order model based on the theory of the equivalent mechanical models for the description of the sloshing dynamics. This model is then introduced into an integrated modeling that accounts for both rigid and elastic behavior of flexible aircraft. The formulation also provides for fully unsteady aerodynamics modeled in the frequency domain via doublet lattice method and recast in time-domain state-space form by means of a rational function approximation. The case study consists of the so-called body freedom flutter research model equipped with a single tank, partially filled with water, located underneath the center of mass of the aircraft. The results spotlight that neglecting such sloshing effects considering the liquid as a frozen mass may overshadow possible instabilities, especially for mainly rigid-body dynamics
Experimental data-driven reduced-order modeling of nonlinear vertical sloshing for aeroelastic analyses
This thesis focuses specifically on the study of nonlinear sloshing effects caused by large tank motions in a direction perpendicular to the free liquid surface with emphasis on aeronautical applications. Sloshing is a phenomenon that typically occurs in aircraft tanks as they are subjected to loads caused by gusts, turbulence and landing impacts.
This type of sloshing leads to a noticeable increase in overall structural damping, yet it is generally not modeled in the design phase of modern aircraft.
The identification and study of such dissipative effects may enable the development of less conservative aircraft configurations in the future, allowing for increasingly lighter structures and reduced environmental impact. The present thesis proposes a combined experimental and numerical approach aimed at obtaining reduced-order models for vertical sloshing, to be subsequently integrated into aeroelastic modeling and applications for the assessment of their effects on overall performance.
An experimental campaign is first carried out to characterise the nonlinear dissipative behaviour of vertical sloshing for different filling levels. Specifically, a controlled electrodynamic shaker is employed to provide vertical displacement by means of sine-sweep excitation. By exploiting vertical harmonic motion, it is shown how the frequency and amplitude of the imposed excitation significantly influence the dissipative capabilities of the sloshing liquid.
The same experiment is used to create a database - with an acquisition phase that considers vertical sloshing as an isolated system - to build a neural-network-based reduced-order model. The dynamics to be modeled is considered as a black box process, leading to the identification of a surrogate model driven only by input/output signals, regardless the knowledge of the internal dynamics. In order to assess the capability of the identified reduced order model for sloshing, the same tank used to generate the training data is mounted at the free end of a cantilever beam to create a new experimental setup in which a fluid-structure interaction scenario is expected.
Indeed, this experiment provides experimental data for the validation of the identified dynamic model by comparison with numerical data. The comparison is carried out using a dynamic virtual simulation model corresponding to the experiment, in which the numerical model of the beam interacts with the reduced-order model simulating the sloshing dynamics. Finally, the experimentally validated reduced-order model is used in two different aeroelastic applications - wing prototype and flying wing model - to finally predict the dissipative effects induced by vertical sloshing on the aeroelastic response. Aeroelastic response analyses under pre- and post-critical conditions showed how the vertical sloshing dynamics helps to alleviate the dynamic loads due to severe gusts while providing limit cycle oscillation beyond the flutter margin
Percezione e geometria. L'informatizzazione della geometria descrittiva per la creazione di nuovi modelli finalizzati alla percezione attiva degli spazi multimediali
Il MUNDI, Museo nazionale dell’italiano. Storia e sviluppo di un'idea
Come rappresentare la lingua italiana in un museo oggi? Basandosi sull’esperienza maturata in oltre vent’anni di riflessioni e confronti, il gruppo di lavoro istituito dal Mibact nel 2019 ha messo a punto un ambizioso progetto museale, che è attualmente in corso di realizzazione presso l’Oratorio di Santa Maria Novella a Firenze. Nel contributo sono condensati alcuni punti fermi di questo percorso
LA REVISIONE DEL TESTO TRADOTTO: DALLA PARTE DELL’ITALIANO
Da qualche tempo anche in Italia è aumentata l’attenzione per la procedura di revisione, in particolare del testo tradotto da altre lingue. Nell’articolo si prendono in esame le cause che rendono necessaria la revisione di un testo tradotto a distanza di tempo, soprattutto alla luce dei fenomeni di cambiamento che hanno interessato l’italiano recente. Sulla base di studi che sottolineano una certa conservatività linguistica nelle traduzioni letterarie e non letterarie, si insiste sulla necessità che i revisori acquisiscano grande consapevolezza della norma dell’italiano di oggi e dell’accettabilità di diverse varietà di lingua. Il revisore, invisibile responsabile finale della qualità del testo, può utilmente servirsi delle riflessioni presentate nel dibattito corrente sulla nozione di errore nel contesto dell’apprendimento e della complessa attrezzatura messa a punto per la descrizione dell’italiano contemporaneo e delle sue varietà . Revising translated texts: the italian point of viewFor some time, attention has been paid to the revision process in Italy, particularly texts translated from other languages. The article examines why it is necessary to review a translated text after some time has passed, especially in light of the changes that have affected recent Italian. Based on studies emphasizing a certain linguistic conservatism in literary and non-literary translations, there is a need for translators to gain great awareness of current standard Italian and accept the different varieties of language. The translator, responsible for the final quality of the text, can use the reflections presented in the current debate on the notion of error in the context of learning and the complex set-up for the description of contemporary Italian and its varieties
Experimental Validation of Neural-Network-Based Nonlinear Reduced-Order Model for Vertical Sloshing
In this paper, a nonlinear reduced order model based on neural networks is introduced in order to model vertical sloshing for use in fluid-structure interaction simulations. A box partially filled with water, representative of a wing tank, is first tested to identify a neural network model and then attached to a cantilever beam to test the effectiveness of the neural network in predicting the sloshing forces when coupled with the structure. The experimental set-up is equipped with accelerometers and load cells at the interface between the tank and an electrodynamic shaker, which provides vertical acceleration to the tank. Accelerations and interface forces measured during the experimental tests are employed to identify a recurrent network able to return the vertical sloshing forces when the tank is set on vertical motion. The identified model is then experimentally tested and assessed by its integration on the tip of a cantilever beam. The free response of the experimental setup are compared with those obtained by simulating an equivalent virtual model in which the identified reduced-order model is integrated to account for the effects of vertical sloshing
Percezione e geometria. L'informatizzazione della geometria descrittiva per la creazione di nuovi modelli finalizzati alla percezione attiva degli spazi multimediali
Per un dizionario degli italianismi nel mondo: rilancio di un progetto
Ten years have almost passed since the project of a collection of Italianisms edited by Luca Serianni
was stopped. Now a new research called oim (Osservatorio degli Italianismi nel Mondo:
Observatory of Italianisms in the world) is starting with the support of the Accademia della
Crusca. This paper deals with some considerations on the kind of work necessary for this challenge
(first phase: definition of Italianism; second phase: data collection; third phase: control).
Finally, it offers a reliable marking system that can make the degree of stabilization of the terms
easily recognizable and can show how they mixed to various host languages
Grand tour e piccoli tour
Nel ricordo dedicato a Luca Serianni, tragicamente scomparso nel luglio 2022, si ripercorrono le riflessioni sul viaggio (e la pratica personale) a partire dai suoi studi: dai commenti all’opera poetica di Paolo Rolli al contributo dedicato alla percezione dell’italiano e dell’Italia da parte dei viaggiatori stranieri. Si offrono così alcuni spunti per descrivere il senso del viaggio per Luca Serianni: un viaggio reale nei luoghi visitati all’estero e soprattutto in Italia, ma anche un viaggio figurato, nei tanti ambiti di esplorazione scientifica che hanno costituito il campo di ricerca dello studioso.
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