Simulation of vorticity wind turbines : a coupled discret element method and finite volume method for the simulation of elastic bodies

Several devices and man-made structures interact dynamically with fluids such as water and air, behaving essentially as flexible elastic systems that undergo large deformations and complex dynamics. The design and analysis of the variable degrees of effciency that these devices may have under different flow conditions can be carried out using numerical modeling tools. Devising ways of simulating the behavior of fluids with ever increasing accuracy is essential to save time and resources while testing the potential of new technologies. One of the fields of engineering that has shown most significant growth in recent years is the generation of energy from renewable sources. The present research adapts mathematical methods, still new to the field, to represent ways of dealing with flows of fluid in bidirectional interactions with those new technologies, and particularly applies them to the exploration of a new kind of vertical blade-less turbine that gathers energy from the vortex induced vibrations (VIV) of a relatively short and scalable mast. This device is very promising for several logistic and cost related reasons, especially when considering the difficulties of implementing new approaches in developing countries, but until now it has not been tested under rigorous theoretical models or with simulation methods that can have true predictive value. This research a) presents a framework for such modeling by coupling the discrete element method (DEM) with the finite volume method (FVM), b) compares the theoretical method with previous tests that had both computational and physical experiments to be contrasted, and c) suggests ways to make the technology more efficient and adaptable to changing conditions.Diversas estructuras y dispositivos creados por el hombre deben interactuar mecánicamente con fluidos, en particular agua y aire. Cuando estas estructuras constituyen además sistemas elásticos y flexibles, la interacción con fluidos involucra una dinámica doblemente compleja, pues los flujos generan deformaciones en las estructuras, que a su vez determinan y modulan las respuestas del fluido. Durante los procesos de diseño, el análisis de los respectivos grados de eficiencia que estos dispositivos alcanzarán bajo la acción de diversas condiciones de flujo, puede llevarse a cabo mediante herramientas de modelación numérica. Idear formas de simular la interacción de fluidos y estructuras con precisión resulta esencial para evitar inútiles pérdidas de tiempo y recursos a la hora de evaluar el potencial de nuevas tecnologías. Una de las ramas de la ingeniería que ha crecido de un modo más significativo en las últimas décadas es la generación de energía a partir de fuentes renovables. La presente investigación adapta métodos matemáticos de representación, todavía nuevos en el área, para simular la interacción fluido-estructura en esas nuevas tecnologías, y en particular los aplica a un nuevo tipo de turbina eólica sin aspas, que extrae energía a través de la vibracion inducida por el desprendimiento de vórtices (VIV) de un mástil vertical flexible. Esta tecnología se presenta como muy prometedora, tanto por razones de logística como de costo, especialmente si se consideran las dificultades para implementar nuevos recursos técnicos en países en desarrollo, pero hasta ahora no han sido evaluadas bajo modelos teóricos rigurosos o con métodos de simulación con verdadero valor predictivo. Esta tesis a) presenta un marco de referencia para este tipo de simulaciones acoplando el Método de Elementos Discretos (DEM) con el Método de Volúmenes Finitos (FVM), b) compara modelos teóricos de pruebas anteriores que contiene tanto experimentación física como computacional, lo que permite contrastar resultados, y c) sugiere formas de hacer esta tecnología más eficiente y adaptable a condiciones variables

"De la pirotechnia" di Vannoccio Biringuccio Senese: versione elettronica multilingua full-text.

Textual archive of Biringuccio\u27s work "De la pirotechnia".Archivio testuale con interfaccia DBT-Web dell\u27opera di Biringuccio Senese "De la pirotechnia", maestro di metallurgia e fusione dei metalli

Experimental Analysis of Gas–Liquid–Solid Three-Phase Flows in Horizontal Pipelines

The dynamics of three-phase flows involves phenomena of high complexity whose characterization is of great interest for different sectors of the worldwide industry. In order to move forward in the fundamental knowledge of the behavior of three-phase flows, new experimental data has been obtained in a facility specially designed for flow visualization and for measuring key parameters. These are (1) the flow regime, (2) the superficial velocities or rates of the individual phases; and (3) the frictional pressure loss. Flow visualization and pressure measurements are performed for two and three-phase flows in horizontal 30 mm inner diameter and 4.5 m long transparent acrylic pipes. A total of 134 flow conditions are analyzed and presented, including plug and slug flows in air–water two-phase flows and air–water-polypropylene (pellets) three-phase flows. For two-phase flows the transition from plug to slug flow agrees with the flow regime maps available in the literature. However, for three phase flows, a progressive displacement towards higher gas superficial velocities is found as the solid concentration is increased. The performance of a modified Lockhart–Martinelli correlation is tested for predicting frictional pressure gradient of three-phase flows with solid particles less dense than the liquid

The dipole formalism for massive initial-state particles and its application to dark matter calculations

The dark matter abundance plays a crucial role in the determination of the valid parameter space of models both in case of a discovery of dark matter and in the context of exclusion limits. Reliable theoretical predictions of the dark matter relic density require technically demanding precision calculations, which were so far limited in their automation due to challenges in the treatment of infrared divergences appearing in higher order calculations. In particular, massive initial states need to be considered in early Universe computations, so that the known dipole subtraction methods could not be directly exploited. We therefore provide a full generalization of the dipole subtraction method by Catani and Seymour to (SUSY)-QCD with massive initial states. All dipole splitting functions and their integrated counterparts are given explicitly for four different dimensional schemes. To showcase their application, we apply our results to dark matter (co)-annihilation processes in the context of the Minimal Supersymmetric (SUSY) Standard Model (MSSM). We also demonstrate the accuracy of the dipole method by comparing our numerical results with those obtained with the space space slicing method. Our analytical results will facilitate future automation of dark matter abundance calculations at next-to-leading order for both SUSY and non-SUSY models.Comment: 42 pages, 8 figures, 3 table

Valorizzazione del patrimonio letterario della lingua italiana.Il corpus italiano e la legge 488.

The aim of the project is build linguistic resources (data, knowledge and softwares).It aims to make possible,effective and prompt the answer of the Industry,of the Research, italian services at the Society of Information,in a european and global context.Mira a valorizzare le risorse linguistiche dell\u27italiano, il suo corpus e la legge 488

Efficient conversion of chemical energy into mechanical work by Hsp70 chaperones

Hsp70 molecular chaperones are abundant ATP-dependent nanomachines that actively reshape non-native, misfolded proteins and assist a wide variety of essential cellular processes. Here we combine complementary computational/theoretical approaches to elucidate the structural and thermodynamic details of the chaperone-induced expansion of a substrate protein, with a particular emphasis on the critical role played by ATP hydrolysis. We first determine the conformational free-energy cost of the substrate expansion due to the binding of multiple chaperones using coarse-grained molecular simulations. We then exploit this result to implement a non-equilibrium rate model which estimates the degree of expansion as a function of the free energy provided by ATP hydrolysis. Our results are in quantitative agreement with recent single-molecule FRET experiments and highlight the stark non-equilibrium nature of the process, showing that Hsp70s are optimized to convert effectively chemical energy into mechanical work close to physiological conditions

The Shape of a Stretched Polymer

The shape of a polymer plays an important role in determining its interactions with other molecules and with the environment, and is in turn affected by both of them. As a consequence, in the literature the shape properties of a chain in many different conditions have been investigated. Here, we characterize the shape and orientational properties of a polymer chain under tension, a physical condition typically realized both in single-molecule experiments and in vivo. By means of analytical calculations and Monte Carlo simulations, we develop a theoretical framework which quantitatively describes these properties, highlighting the interplay between external force and chain size in determining the spatial distribution of a stretched chain

Tankyrase inhibition impairs directional migration and invasion of lung cancer cells by affecting microtubule dynamics and polarity signals

Raw data for Fig. S2. (XLSX 48 kb

Cytotoxicity of a mitochondriotropic quercetin derivative: Mechanisms

AbstractThe mitochondriotropic compound 7-O-(4-triphenylphosphoniumbutyl)quercetin iodide (Q-7BTPI) in the μM concentration range caused necrotic death of cultured cells by acting as a prooxidant, with generation of superoxide anion in the mitochondria. Externally added membrane-permeating superoxide dismutase or catalase largely prevented death. Rescue by permeant catalase indicates that the toxicant is H2O2, or reactive species derived from it. Rescue by permeant dismutase suggests the possibility of a chain mechanism of H2O2 production, in which dismutation of superoxide constitutes a termination step. Oxidative stress was due to the presence of free phenolic hydroxyls and to accumulation in mitochondria, since the analogous mitochondriotropic per-O-methylated compound -3,3′,4′,5-tetra-O-methyl,7-O-(4-triphenylphosphoniumbutyl) quercetin iodide (QTM-7BTPI)—or Quercetin itself induced no or little superoxide production and cell death. Q-7BTPI did not cause a significant perturbation of the mitochondrial transmembrane potential or of respiration in cells. On the other hand its presence led to inhibition of glutathione peroxidase, an effect expected to accentuate oxidative stress by interfering with the elimination of H2O2. An exogenous permeable glutathione precursor determined a strong increase of cellular glutathione levels but did not rescue the cells. Death induction was selective for fast-growing C-26 tumoral cells and mouse embryonic fibroblasts (MEFs) while sparing slow-growing MEFs. This suggests a possible use of Q-7BTPI as a chemotherapeutic agent