Search results for "FD"

Numerical simulation of transcatheter mitral valve replacement: The dynamic implication of LVOT obstruction in the valve-in-ring case.

2022

Transcatheter mitral valve replacement (TMVR) has been used for “off-label” treatment when annuloplasty band ring for mitral repair fails. However, the complex anatomy and function of the mitral valve may lead to fatal complications as a result of the left ventricular outflow tract (LVOT) obstruction in TMVR. We report the structural and hemodynamic response of LVOT obstruction resulting from TMVR with the Edwards SAPIEN 3 Ultra (S3) device. We modified the original Living Heart Human Model (LHHM) to account for a failed mitral valve with an annuloplasty band ring and simulated the cardiac beating condition in the setting of S3 device implantation. Findings demonstrated a high dynamic behav…

Tunnel fire active protection: improving ventilation system

2019

Abstract The main aim of this work is to evaluate how the use of an active protection method, consisting in an improved forced longitudinal ventilation system, can determine a positive impact on heat extraction and people evacuation time in a tunnel fire scenario, by considering a case study which simulations are based on a real gallery.

Unsteadiness and transition to turbulence in woven spacer filled channels for Membrane Distillation

2017

To characterize the performance of Membrane Distillation (MD) modules, channels filled with woven spacers were investigated by Computational Fluid Dynamics (including Direct Numerical Simulations and the use of the SST k-ω turbulence model) and by parallel experiments with Thermochromic Liquid Crystals. The cases considered here regard mutually orthogonal filaments with a spacer pitch to channel height ratio P/H=2, two spacer orientations θ with respect to the main flow (0° and 45°), and bulk Reynolds numbers Re from ∼200 to ∼2000, an interval of great interest in practical MD applications. For both values of θ, CFD predicted steady-state flow for Re up to ∼300, and chaotic flow …

STATE BUILDING, RURAL DEVELOPMENT, AND THE MAKING OF A FRONTIER REGIME IN NORTHEASTERN ETHIOPIA, c. 1944–75

2016

AbstractCombining a set of grey literature and primary sources, this article analyses the rise and fall of the sultanate of Awsa, northeastern Ethiopia, between 1944 and 1975. Ali Mirah exploited the typical repertoires of a frontier regime to consolidate a semi-independent Muslim chiefdom at the fringes of the Christian empire of Ethiopia. Foreign investors in commercial agriculture provided the sultanate and its counterparts within the Ethiopian state with tangible and intangible resources that shaped the quest for statecraft in the Lower Awash Valley.

New relations between professional and work’s organizations introduced by computer applications, special vessel case study

2019

At present time the project of a naval vehicle, where with the word project we refer to all the process of design and manufacturing, especially when the vehicle offers special formal and performance characteristics, involves a number of operators that has been increasing considerably in recent decades, and this increased complexity can be correlated with dimensional and typological growth of many categories of ships. Simultaneously we are witnessing a complete new project approach, where the possibility given by the computer contribution to represent processes and results becomes crucial. The paper aims to investigate the consequences of this progress in the organization of the project and …

Large-Eddy Simulation e tecnica LS-PIV: lo studio della turbolenza superficiale

2021

Gli avanzamenti tecnologici degli ultimi decenni hanno fatto registrare la rapida diffusione di tecnologie innovative con cui condurre un monitoraggio ambientale più efficiente ed efficace. Nel campo del monitoraggio fluviale sono sempre più utilizzate le tecniche basate sull’elaborazione di immagini, fornendo una valida alternativa alle metodologie tradizionalmente adottate. Le tecniche ottiche restituiscono infatti misure non intrusive, assicurando migliori condizioni di sicurezza per gli operatori. I metodi ottici più utilizzati sono la Large-Scale Particle Image Velocimetry (LS-PIV) [1] e la Large-Scale Particle Tracking Velocimetry (LS-PTV) [2]. Le tecniche LS-PIV e LS-PTV si basano su…

Regional flow duration curves for ungauged sites in Sicily

2011

Abstract. Flow duration curves are simple and powerful tools to deal with many hydrological and environmental problems related to water quality assessment, water-use assessment and water allocation. Unfortunately the scarcity of streamflow data enables the use of these instruments only for gauged basins. A regional model is developed here for estimating flow duration curves at ungauged basins in Sicily, Italy. Due to the complex ephemeral behaviour of the examined region, this study distinguishes dry periods, when flows are zero, from wet periods using a three parameters power law to describe the frequency distribution of flows. A large dataset of streamflows has been analysed and the param…

Oral CorticoSteroid sparing with biologics in severe asthma: A remark of the Severe Asthma Network in Italy (SANI)

2020

According to the data derived from several national and international registries, including SANI (Severe Asthma Network Italy), and considering the strong impact that frequent or regular use of oral corticosteroid has on quality of life (QoL) of severe asthmatics, as well as on the costs for managing corticosteroid-related diseases, oral corticosteroid sparing up to withdrawal should be considered a primary outcome in the management of severe asthma. New biologics have clearly demonstrated that this effect is possible, with concomitant reduction in the rate of exacerbations and in symptom control. Then, there is no reason for using so frequently oral corticosteroid before having explored al…

Numerical assessment of the thermal-hydraulic performances of the ITER Blanket cooling system

This thesis has covered the main research activities carried out during the candidate Ph.D. course of the XXXI Cycle on “Energia e Tecnologie dell’Informazione - curriculum Fisica Tecnica e Ingegneria Nucleare” (Energy and Information Technologies - Applied Physics and Nuclear Engineering curriculum), held at the University of Palermo, in the time frame that goes from the end of 2015 to the end of 2018. In particular, it focusses on the activities carried out at the DEIM in cooperation with the ITER Organisation on the “Hydraulic Analysis of Blanket Cooling System” and it has aimed to investigate the thermal-hydraulic behaviour of the ITER blanket cooling system under nominal steady-state c…

ASSESSMENT OF CORRUPTION EFFECT ON FOREIGN INVESTMENT FLOWS

2011

The purpose of the present paper is to investigate the impact of corruption on foreign direct investment (FDI) flows. Using data from the International Monetary Fund, Transparency International and United Nations conference about commerce and development data bases a cross-section econometric model was estimated to evaluate in which way and how strong corruption influence FDI inflows. Econometric modelling covers the period from year 2000 to 2007 and the data about 82 world countries that constitute more than 500 records. The main conclusion of the paper is that corruption has a negative and significant impact on the foreign direct investment inflows. Thus, changes in the level of corruptio…