On the development of an efficient regenerative compressor

AbstractRegenerative compressors are attractive machines used in several industrial processes. Their main characteristic is the highly three-dimensional development of the flow. Consequently, usual approach for axial or centrifugal compressors design are not an affordable strategy. The analysis of the rotor/stator coupling is the main issue in the design of regenerative compressors because of the vane-less nature of the stator and the characteristic trajectory of the flow. This paper describes the design of an efficient regenerative compressor based on a highly detailed Reynolds Averaged Navier-Stokes (RANS) analysis. The targets of the activity are defined in terms of expected mass-flow, pressure rise and compressor efficiency, and then a preliminary design is performed using an in-house mono-dimensional tool based on simplified assumptions for the nominal operating conditions. Once the model provided the most promising geometrical characteristics for the target operating point, three-dimensional steady RANS analyses are performed to evaluate the actual performance of the compressor for a wide range of mass-flow values. Special attention has been paid to the generation of the computational mesh and a specific solution for the rotor row has been developed. Compressibility effects are non-negligible since the flow Mach number is higher than 0.5 in several compressor sections, including the leakage zone regions where the losses are higher. The rotor and the full compressor efficiencies are evaluated and discussed to underline the importance of the rotor/volute coupling. The flow behaviour inside of the volute as well as the distribution of losses is also discussed and some guidelines for the efficient design of regenerative compressors are presented

Particle identification using current maximum obtained from charge

Particle identification plays a crucial role in the study of isospin dynamics, and several identification techniques have been developed in the last decades. Amongst them, the pulse shape analysis methods allow to identify those fragments that are fully stopped in a single detector layer by studying the shape of the signal induced by the impinging fragment. The correlation of the maximum of the induced current signal with the energy of the fragment is known to give a good isotopic identification, but requires to acquire the current signal. However, when the current signal isn’t available, it can be reconstructed from the digitized charge signal. The algorithms used for the reconstruction are presented briefly along with the first results obtained during the DIGIGARF experiment at LNL

LABEC, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage

The LABEC laboratory, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage, located in the Scientific and Technological Campus of the University of Florence in Sesto Fiorentino, started its operational activities in 2004, after INFN decided in 2001 to provide our applied nuclear physics group with a large laboratory dedicated to applications of accelerator-related analytical techniques, based on a new 3 MV Tandetron accelerator. The new accelerator greatly improved the performance of existing Ion Beam Analysis (IBA) applications (for which we were using since the 1980s an old single-ended Van de Graaff accelerator) and in addition allowed to start a novel activity of Accelerator Mass Spectrometry (AMS), in particular for 14C dating. Switching between IBA and AMS operation became very easy and fast, which allowed us high flexibility in programming the activities, mainly focused on studies of cultural heritage and atmospheric aerosol composition, but including also applications to biology, geology, material science and forensics, ion implantation, tests of radiation damage to components, detector performance tests and low-energy nuclear physics. This paper describes the facilities presently available in the LABEC laboratory, their technical features and some success stories of recent applications

g-factor measurements of isomeric states in 174W

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.ISBN: 978-88-7438-101-2; International audience; The experimental setup GAMIPE used for gyromagnetic factormeasurements at Laboratori Nazionali di Legnaro and a recent experimentalwork regarding K-isomers in 174W are described. Aim ofthe experiment is to study the detailed structure of the isomeric stateswave functions, by the measurement of the magnetic dipole moments.This piece of information can provide interesting hints for theoreticalmodels. Preliminary results concerning the population of the isomersof interest and half-lives are presented

Visiones y propuestas hacia un urbanismo emergente: un viaje por la ciudad viva 2006-2016.

1. Introducción – El Proyecto La ciudad viva surge en Andalucía (entre los años 2006 y 2008) como búsqueda de soluciones y herramienta de participación ante las numerosas problemáticas de la ciudad contemporánea, logrando ser el canal de reflexión y comunicación institución-ciudadanía del ámbito urbanístico más utilizado en nuestro país durante años. Su contenido, artículos, revistas y post generados desde su nacimiento hasta 2016 por más de 50 corresponsales repartidos por el todo el mundo, será la fuente documental de esta investigación, que defiende que sus múltiples voces y perspectivas -ordenadas, identificadas y relacionadas- descubren nuevas visiones y propuestas hacia un urbanismo emergente. Su reciente cierre (a principios de 2017) por la Institución que la creó y mi implicación con el proyecto como su Coordinadora, me obligan a rescatar de alguna forma el conocimiento contenido en la plataforma, verdadera inteligencia efectiva y colectiva, y transferirla al conjunto de actores que participamos en la vida y construcción de la ciudad. 2. Métodología – Tras organizar todo el contenido de la plataforma en regiones o ZONAS según temática, elaboro una serie de RELATOS literarios que las recorren referenciando sus numerosas fuentes multidisciplinares. El relato a través de la Zona 1 (Z1), Generación rotonda, la crisis de la habitabilidad contemporánea, son las memorias de una generación cuyo imaginario urbano ha asumido la homogenización que han sufrido las ciudades, las consecuencias de una transformación del paisaje social y cultural a causa de la burbuja inmobiliaria, los efectos de la “zonificación” y las nuevas tecnologías. Zona 2 (Z2), Flânerie es femenino, caminar con perspectiva de género, narra en primera persona cómo se usa y vive la calle y los espacios públicos de la ciudad desde la perspectiva de género y la experiencia de la maternidad. Zona 3 (Z3), Periferias, la intervención pública en barrios europeos de vivienda social 50-80, son diarios de viaje a los barrios analizados en La ciudad viva que incluyen reflexiones de sus corresponsales en estas ciudades y sus políticas públicas de rehabilitación urbana. Zona 4 (Z4), Derecho a techo, alternativas habitacionales; revisa las alternativas habitacionales citadas en La ciudad viva (principalmente latinoamericanas) e incluye varias conversaciones que giran en torno a ellas (Vanesa Valiño, Directora del Observatori Desc; Raúl Robert Oleas, miembro de la Cooperativa de viviendas Sostrecivic; Josefa Domínguez, arquitecta municipal Marinaleda o Raúl Valdés, miembro de la Cooperativa de Ayuda Mutua en Uruguay, entre otros). 3. Conclusiones – Del diagnóstico a la propuesta: Los relatos comienzan centrándose en referencias con carácter más analítico, y terminan en el ámbito propositivo. Las propuestas, identificadas, conectadas y relacionadas, concluyen en ITINERARIOS que, apoyados en una serie de diagramas, permiten identificar nuevos instrumentos “hacia un urbanismo emergente”. Finalmente, mostraré cómo aplico estos nuevos instrumentos derivados de La Ciudad Viva a la praxis, en el ámbito de Sevilla, lugar donde trabajo en planeamiento actualmente en el Plan Reaviva, 2015-2019, Premio Andalucía de Urbanismo) como laboratorio de ensayo urbano

Dyspnea assessment and adverse events during sputum induction in COPD

BACKGROUND: The inhalation of normal or hypertonic saline during sputum induction (SI) may act as an indirect bronchoconstrictive stimulus leading to dyspnea and lung function deterioration. Our aim was to assess dyspnea and adverse events in COPD patients who undergo SI following a safety protocol. METHODS: Sputum was induced by normal and hypertonic (4.5%) saline solution in 65 patients with COPD of varying severity. In order to minimize saline-induced bronchoconstriction a protocol based on the European Respiratory Society sputum induction Task group report was followed. Dyspnea change was scored using the Borg scale and lung function was assessed by spirometry and oximetry. RESULTS: Borg score changes [median(IQR) 1.5(0–2)] were observed during SI in 40 subjects; 16 patients required temporary discontinuation of the procedure due to dyspnea-general discomfort and 2 did not complete the session due to dyspnea-wheezing. The change in Borg dyspnea score was significantly correlated with oxygen saturation and heart rate changes and with discontinuation of the procedure due to undesired symptoms. 19 subjects presented an hyperresponsive reaction (decline>20% from baseline FEV(1)). No significant correlation between Borg changes and FEV(1)decline was found. Patients with advanced COPD presented significantly greater Borg and oxygen saturation changes than patients with less severe disease (p = 0.02 and p = 0.001, respectively). Baseline FEV(1), oxygen saturation and 6MWT demonstrated significant diagnostic values in distinguishing subjects who develop an adverse physiologic reaction during the procedure. CONCLUSION: COPD patients undergoing SI following a safety protocol do not experience major adverse events. Dyspnea and oxygen desaturation is more likely to occur in patients with disease in advanced stages, leading to short discontinuation or less frequently to termination of the procedure. Baseline FEV(1), oxygen saturation and 6MWT may have a prognostic value for the development of these adverse events and might be useful to be evaluated in advance