AN ANALYSIS OF REGIONAL LEXICAL VARIATION IN CALIFORNIA ENGLISH USING SITE-RESTRICTED WEB SEARCHES

Lo studio esamina la variazione lessicale regionale in forma scritta nell’inglese standard in California. Attraverso ricerche in rete limitate a 336 siti di giornali online con sede in 270 città in California, vengono raccolti i valori di 45 variabili continue di alternanze lessicali e quindi calcolati come proporzioni. Tecniche statistiche di autocorrelazione spaziale globale e locale analizzano i valori. I risultati delle analisi, riportati in 90 mappe, confermano la distribuzione regionale delle variabili in California. Le 45 variabili lessicali sono poi esaminate con tecniche statistiche multivariate per individuare le relazioni linguistiche tra le città della California esaminate. L’analisi fattoriale, che rappresenta il 50,5% della variazione nei dati, evidenzia tre aree nella distribuzione regionale lessicale: nord/sud, urbano/rurale, e aree centrali e basso meridionali/aree alto meridionali e del nord. L’analisi dei cluster gerarchica distingue inoltre sei regioni dialettali principali in California: quella del Nord, quella di Sacramento-Santa Cruz, quella della San Francisco Bay Area, quella centrale, quella alto meridionale, e quella basso meridionale. Cinque mappe multivariate sono fornite nella tesi. La spiegazione dei risultati si basa sia su modelli di insediamento storico che su una spiegazione socio-culturale, che si riflettono nel linguaggio in California.The study examines regional lexical variation in written Standard California English. The values​of 45 continuous lexical alternation variables are gathered through site-restricted web searches in 336 online newspaper websites based in 270 locations in California and then calculated as proportions. Statistical techniques analyze global and local spatial autocorrelation values. The results of the analysis, reported in 90 maps, confirm the regional distribution of the variables in California. The 45 lexical variables are then analyzed with multivariate techniques to identify the linguistic relations between the surveyed California cities. Factor analysis, which accounts for 50.5% of the variation in the data, highlights three areas in the regional lexical distribution: north/south, urban/rural, central and lower southern/upper southern and northern areas. The hierarchical cluster analysis also distinguishes six major dialect regions in California: the North dialect region, the Sacramento-Santa Cruz dialect region, the San Francisco Bay Area dialect region, the Central dialect region, the Upper Southerns dialect region, and the Lower Southern dialect region. Five multivariate maps are provided in the thesis. The explanation of the results is based both on historical settlement patterns and on a socio-cultural explanation, which are reflected in the language in California

Impact of Leading Edge Roughness in Cavitation Simulations around a Twisted Foil

The simulation of fully turbulent, three-dimensional, cavitating flow over Delft twisted foil is conducted by an implicit large eddy simulation (LES) approach in both smooth and tripped conditions, the latter by including leading-edge roughness. The analysis investigates the importance of representing the roughness elements on the flow structures in the cavitation prediction. The results include detailed comparisons of cavitation pattern, vorticity distribution, and force predictions with the experimental measurements. It is noted that the presence of roughness generates very small cavitating vortical structures which interact with the main sheet cavity developing over the foil to later form a cloud cavity. Very similar to the experimental observation, these interactions create a streaky sheet cavity interface which cannot be captured in the smooth condition, influencing both the richness of structures in the detached cloudy cavitation as well as the extent and transport of vapour. It is further found to have a direct impact on the pressure distribution, especially in the mid-chord region where the shed cloud cavity collapses

Il contratto a tutele crescenti nel prisma delle convenienze e dei costi d\u2019impresa

SOMMARIO: 1. Posizione del problema. \u2013 2. L\u2019esonero contributivo e la deducibilit\ue0 ai fini Irap nella legge n. 190/2014 (legge di stabilit\ue0 2015) per il contratto a tutele crescenti. \u2013 2.1. L\u2019esonero contributivo per gli assunti a tempo indeterminato. \u2013 2.2. La deducibilit\ue0 ai fini Irap del costo del lavoro. \u2013 3. Il sistema di incentivazione per assumere a tempo indeterminato. \u2013 3.1. Una esemplificazione per l\u2019industria metalmeccanica e per il commercio. \u2013 3.2. Una esemplificazione per il settore meccanico dell\u2019artigianato. \u2013 4. Il contratto a tutele crescenti a confronto con le altre tipologie contrattuali nella scelta gestionale. \u2013 4.1. Aziende non artigiane e di maggiori dimensioni. \u2013 4.2. Aziende artigiane e di minori dimensioni. \u2013 5. Limiti e vantaggi degli incentivi per il nuovo contratto a tutele crescenti. \u2013 6. L\u2019impatto del contratto a tutele crescenti su produttivit\ue0 e struttura della retribuzione

Comparative analysis of tip vortex flow using RANS and LES

The current study focuses on the numerical analysis of tip vortex flows, with the emphasis n the investigation of turbulence modelling effects on tip vortex prediction. The analysis includes comparison of RANS and LES methods at two different mesh resolutions. Implicit LES, ILES, modelling is employed here to mimic the turbulent viscosity. In RANS, the two equation k-ω SST model is adopted. In order to also address possible benefits of using streamline curvature variations in RANS, two curvature correction methods proposed for k-ω SST are tested, and compared. ILES results show very good agreement with the experimental observations. The predicted vortex in ILES is also stronger than RANS predictions. ILES has predicted accelerated vortex core axial velocity very well, while tested RANS models under predict the axial velocity. Adoption of curvature correction has not improved the tip vortex prediction, even though it has reduced the turbulent viscosity at the vortex core

BEBOP: Bidirectional dEep Brain cOnnectivity maPping

Functional connectivity mapping provides information about correlated brain areas, useful for many applications such as on mental disorders. This work aims to improve this mapping by using deep metric learning considering the directionality of information flow and time-domain features. To deal with the computational cost of a complete pairwise combination network, we trained a network able to recognize similar signals and, after training, feed it with all combinations of signals from each brain area. The labels of similarity or dissimilarity are determined by agglomerative clustering using the Jensen-Shannon Distance as a metric. To validate our approach we employed a resting-state eye-open functional MRI dataset from ADHD and healthy subjects. Once registered, the signals are filtered and averaged by area with a functional trimmed mean. After obtaining the connectivity maps from each subject, we perform a feature importance selection using logistic regression. The ten most promising areas were extracted, such as the frontal cortex and the limbic system. These results are in complete agreement with previous literature. It is well known those areas are mainly involved in attention and impulsivity

New Insights into Roughness Applications in Tip Vortex Cavitation Inception Mitigation

Tip vortex cavitation (TVC) is usually the first type of cavitation that appears on a propeller. Therefore, it is considered as the main cavitation characteristics to avoid in the design procedure of low-noise propellers, where their operating profiles demand very low radiated noise emissions. The current study includes both numerical and experimental analyses of blade surface roughness application in order to mitigate TVC inception. The investigation consists of applying roughness application on a classical benchmark, an elliptical foil, and on a propeller selected from a Kongs-berg research series of highly skewed propellers having a low effective tip load. The numerical simulations are performed on an appropriate grid resolution for tip vortex propagation, at least 32 cells per vortex diameter by using Implicit Large Eddy Simulation (ILES) for unsteady simulations, and RANS using the SST k − ω model with a curvature correction for steady simulations. Two approaches are considered to include roughness in the numerical simulations: using a rough wall function and resolving the flow around the roughness elements. To minimize the negative effects of the roughness on the propeller performance, the roughness area is optimized by simultaneous consideration of the tip vortex mitigation and performance degradation. Experimental measurements of the elliptical foil are conducted to support the CFD study at different operating conditions and with different roughness patterns while LDV and high-speed video recordings are used to collect the data. The tested conditions include both cavitating and inception of TV flows on the smooth and roughened foil to provide further insights on the usage of roughness. For the elliptical foil, it is found that the application of roughness can reduce the cavitation number for cavitation inception, σ i , by 35 % while keeping the performance degradation less than 1% compared to the smooth foil condition. The average reduction of the TVC inception number achieved by using roughness on the propeller is around 21% with a performance degradation of around 1.5% compared to the smooth propeller condition

Propeller tip vortex cavitation mitigation using roughness

This paper presents an investigation of roughness application on marine propellers in order to alter their tip vortex properties, and consequently mitigate tip vortex cavitation. SST kOmega model along with a curvature correction is employed to simulate the flow on an appropriate grid resolution for tip vortex propagation, at least 32 cells per vortex diameter. The roughness is modelled by using a rough wall function to increase the turbulent properties in roughed areas. In one case, roughness geometry is included as a part of the blade geometry, and the flow around them are resolved. To minimize the negative effects of the roughness on the propeller performance, the roughness area is optimized by simultaneous consideration of the tip vortex mitigation and performance degradation. For the considered operating condition, it is found that having roughness on the tip region of suction side can reduce the cavitation inception by 18 % while keeping the performance degradation in a reasonable range, less than 2%

Investigations of Tip Vortex Mitigation By Using Roughness

The application of artificial roughness to mitigate tip vortex cavitation inception is analyzed through numerical and experimental investigations carried out on an elliptical foil. Different roughness configurations and sizes are tested and effects on cavitation inception, drag, and lift, are studied. Implicit Large Eddy Simulation (ILES) is employed to conduct the simulation on a proper grid resolution having the tip vortex spatial resolution as fine as 0.062 mm. Two different approaches including using a rough wall function and resolving the flow around roughness elements are evaluated. New experiments, performed in the cavitation tunnel at Kongsberg Hydrodynamic Research Centre, for the rough foil are presented.The vortical structures and vorticity magnitude distributions are employed to demonstrate how different roughness patterns and configurations contribute to the vortex roll-up and consequently on the tip vortex strength. It is found that the application of roughness on the leading edge, tip region and trailing edge of the suction side are acceptable to mitigate the tip vortex and also to limit the performance degradation. This is regarded to be in close relation with the way that the tip vortex forms in the studied operating condition. The analysis of boundary layer characteristics shows a separation line caused by roughness is the reason for a more even distribution of vorticity over the tip compared to the smooth foil condition leading to a reduction in vortexstrength. For the optimum roughness pattern, both the numerical results and experimental measurements show a decrease in the tip vortex cavitation inception as large as 33 % compared to the smooth foil condition with a drag force increase observed to be less than 2 %

Propeller tip vortex mitigation by roughness application

In this study, the application of surface roughness on model and full scale marine propellers in order to mitigate tip vortex cavitation is evaluated. To model the turbulence, SST k−ω model along with a curvature correction is employed to simulate the flow on an appropriate grid resolution for tip vortex propagation, at least 32 cells per vortex diameter according to our previous guidelines. The effect of roughness is modelled by modified wall functions. The analysis focuses on two types of vortices appearing on marine propellers: tip vortices developing in lower advance ratio numbers and leading edge tip vortices developing in higher advance ratio numbers. It is shown that as the origin and formation of these two types of vortices differ, different roughness patterns are needed to mitigate them with respect to performance degradation of propeller performance. Our findings clarify that the combination of having roughness on the blade tip and a limited area on the leading edge is the optimum roughness pattern where a reasonable balance between tip vortex cavitation mitigation and performance degradation can be achieved. This pattern in model scale condition leads to an average TVC mitigation of 37% with an average performance degradation of 1.8% while in full scale condition an average TVC mitigation of 22% and performance degradation of 1.4% are obtained