Contributo per una conoscenza analitica delle Mura Bolognesi: Il rilievo critico

Per la prima volta viene affrontato in modo critico e definito il rilievo diretto delle mura e delle porte della terza cerchia di Bologna. La restituzione grafica del testo architettonico è fondamentale non solo per gli studi sui materiali e sulle tecniche che compongono i vari manufatti afferenti al sistema fortificato, ma anche per una lettura cronologica delle stratificazioni che si sono sedimentate nel corso dei secoli. In particolare vengono analizzate direttamente sul testo architettonico le fasi costruttive di Porta Mascarella e Porta San Donato e vengono comparate fra loro cartografie inedite relative alla struttura geometrica delle mura con i relativi elementi accessori, quali cancella, fossato, terrapieni, ecc.

a numerical investigation on the potentials of water injection to increase knock resistance and reduce fuel consumption in highly downsized gdi engines

Abstract 3D CFD analyses are used to analyse the effects of port-injection of water in a high performance turbocharged GDI engine. Particularly, water injection is adopted to replace mixture enrichment while preserving, if not improving, indicated mean effective pressure and knock resistance. A full-load / maximum power engine operation of a currently made turbocharged GDI engine is investigated comparing the actual adopted fuel-only rich mixture to stoichiometric-to-lean mixtures, for which water is added in the intake port under constant charge cooling in the combustion chamber. In order to find the optimum fuel/water balance, preliminary analyses are carried out using a chemical reactor to evaluate the effects of charge dilution and mixture modification on both autoignition delays and laminar flame speeds. Thanks to the lower chemical reactivity of the diluted end gases, the water-injected engine allows the spark advance (SA) to be increased; as a consequence, engine power target is met, or even crossed, with a simultaneous relevant reduction of fuel consumption

Numerical investigation on the effects of bore reduction in a high performance turbocharged GDI engine. 3D investigation of knock tendency

Abstract Downsizing is a must for current high performance turbocharged SI engines. This is often achieved through the reduction of cylinder number, while keeping constant unit displacement and increasing boost pressure. However, the ensuing higher loads strongly increases the risk of abnormal combustion and thermo-mechanical failures. An alternative path to downsizing is the reduction of cylinder bore: this approach is more expensive, requiring a brand new design of the combustion system, but it also provides some advantages. The goal of the present paper is to explore the potential of bore reduction for achieving a challenging downsizing target, while preserving the engine knock safety margins. A current V8 GDI turbocharged sporting engine is taken as a reference, and a preliminary CFD-3D analysis is carried out in order to define the most suitable bore-to-stroke ratio. On this basis, bore is reduced by 11% at constant stroke, thus obtaining a reduction of about 20% on the engine displacement. In order to achieve the same peak power target, both engine boost and spark advance are adjusted until the knock safety margin of the original engine is met. 3D CFD tools, accurately calibrated on the reference engine, are used to address engine design and the calibration of the operating parameters

Many-body effects on excitons properties in GaN/AlGaN quantum wells

The many-body effects on excitons properties in GaN/AlGaN quantum wells are theoretically investigated by using a Green's function model and the electron and hole wave functions calculated either in the envelope function approximation or in the frame of a self-consistent tight-binding model. We show that the built-in field induced by the piezoelectric and spontaneous polarization charge causes a reduction of the exciton binding energy and of the absorption coefficient well below the values expected for the quantum well with flat band. At high carrier concentrations, the many-body screening prevails over the screening of the built-in electric field, causing complete exciton bleaching at typical densities of the order of 1012 cm−2

AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric 14C content at the time of construction of a building. For this reason, the 14C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of 14C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the 14C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples and to infer about the lack of accuracy (when verified) of the applied mortar 14C dating procedure

Mitochondrial DNA Variation among Dogs of Mongolian, Tuvinian and Altaic Nomads

Dogs originated from the domestication of Eurasian grey wolves. From a genetic viewpoint, they can be grouped into two main clusters: the first is represented by several breeds obtained by artificial selection, whereas the second is of dogs that adapted to a human commensal lifestyle. Here we have provided a molecular survey aimed to infer on the genetic variability of dogs from nomadic camps in Mongolia, and the Republics of Tuva and Altai belonging to the Russian Federation. The results provided evidence of typical marks of expanding populations with multiple origins. Such a scenario could be the result of genetic exchanges among dogs from different camps, that were likely mediated by nomads

Protocollo per il campionamento di fitoplancton in ambiente lacustre

No abstract availabl

Clinical Study Respiratory Muscle Training in Patients Recovering Recent Open Cardiothoracic Surgery: A Randomized-Controlled Trial

Objectives. To evaluate the clinical efficacy and feasibility of an expiratory muscle training (EMT) device (Respilift) applied to patients recovering from recent open cardiothoracic surgery (CTS). Design. Prospective, double-blind, 14-day randomisedcontrolled trial. Participants and Setting. A total of 60 inpatients recovering from recent CTS and early admitted to a pulmonary rehabilitation program. Interventions. Chest physiotherapy plus EMT with a resistive load of 30 cm H 2 O for active group and chest physiotherapy plus EMT with a sham load for control group. Measures. Changes in maximal expiratory pressure (MEP) were considered as primary outcome, while maximal inspiratory pressures (MIP), dynamic and static lung volumes, oxygenation, perceived symptoms of dyspnoea, thoracic pain, and well being (evaluated by visual analogic scale-VAS) and general health status were considered secondary outcomes. Results. All outcomes recorded showed significant improvements in both groups; however, the change of MEP (+34.2 mmHg, < 0.001 and +26.1%, < 0.001 for absolute and % of predicted, resp.) was significantly higher in active group. Also VAS dyspnoea improved faster and more significantly ( < 0.05) at day 12, and 14 in active group when compared with control. The drop-out rate was 6%, without differences between groups. Conclusions. In patients recovering from recent CTS, specific EMT by Respilift is feasible and effective. This trial is registered with ClinicalTrials.gov NCT01510275

Effects of macroscopic polarization in III-V nitride multi-quantum-wells

Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we discuss the background theory, the role of spontaneous polarization in this context, and the practical implications of built-in polarization fields in nitride nanostructures. To support our arguments, we present detailed self-consistent tight-binding simulations of typical nitride QW structures in which polarization effects are dominant.Comment: 11 pages, 9 figures, uses revtex/epsf. submitted to PR

Protocollo per il campionamento dei parametri chimico-fisici a sostegno degli elementi biologici in ambiente lacustre

Abstract not availableIl protocollo sul campionamento delle acque lacustri integra completandole le metodologie di campionamento ed analisi del fitoplancton, delle macrofite acquatiche e della fauna a macroinvertebrati in ambiente lacustre riportati nei capitoli successivi di questo Manuale. Anche questo protocollo come i precedenti segue le indicazioni della Direttiva 60/2000/CE (Water Framework Directive, WFD) e del Regolamento per la progettazione del programma di monitoraggio emanato dal Ministero dell?Ambiente e della Tutela del Territorio e del Mare