Agostino Oglialoro Todaro, allievo di Paternò e mentore di Marussia Bakunin

L'attività di ricercatore e di docente di Agostino Oglialoro Todaro è discussa e messa in relazione con il contesto storico nella Napoli di fine ottocento e inizio novecento

C+O detonations in thermonuclear supernovae: Interaction with previously burned material

In the context of explosion models for Type Ia Supernovae, we present one- and two-dimensional simulations of fully resolved detonation fronts in degenerate C+O White Dwarf matter including clumps of previously burned material. The ability of detonations to survive the passage through sheets of nuclear ashes is tested as a function of the width and composition of the ash region. We show that detonation fronts are quenched by microscopically thin obstacles with little sensitivity to the exact ash composition. Front-tracking models for detonations in macroscopic explosion simulations need to include this effect in order to predict the amount of unburned material in delayed detonation scenarios.Comment: 6 pages, 9 figures, uses isotope.sty, accepted for publication in A&

An Unsplit, Cell-Centered Godunov Method for Ideal MHD

We present a second-order Godunov algorithm for multidimensional, ideal MHD. Our algorithm is based on the unsplit formulation of Colella (J. Comput. Phys. vol. 87, 1990), with all of the primary dependent variables centered at the same location. To properly represent the divergence-free condition of the magnetic fields, we apply a discrete projection to the intermediate values of the field at cell faces, and apply a filter to the primary dependent variables at the end of each time step. We test the method against a suite of linear and nonlinear tests to ascertain accuracy and stability of the scheme under a variety of conditions. The test suite includes rotated planar linear waves, MHD shock tube problems, low-beta flux tubes, and a magnetized rotor problem. For all of these cases, we observe that the algorithm is second-order accurate for smooth solutions, converges to the correct weak solution for problems involving shocks, and exhibits no evidence of instability or loss of accuracy due to the possible presence of non-solenoidal fields.Comment: 37 Pages, 9 Figures, submitted to Journal of Computational Physic

analysis of thermal damage in frp drilling

Abstract Among machining operations applied to polymeric composite materials, drilling is the more important one due to the need to implement mechanical couplings, which in most cases are not yet possible using structural adhesives. Such process is very critical because not only it causes the interruption of the fibers continuity, but also it can generate localized thermal shock in the resin, due to the presence of extremely hard and abrasive fibers and to the low thermal conductivity of the resin itself, that limits the heat dissipation. These phenomena are more severe in dry machining process, that are used in aeronautic industry. The poor FRP machinability is manifested in the induced phenomena of delamination, fragmentation and matrix thermal damage that cause negative outcomes, such as the reduction of the material fatigue strength and the consequent decay of long-term performance. The evaluation of such critical issues is possible through indirect analysis, that is through the analysis of some control parameters, such as the process forces and temperatures that assume different values depending on the combination of cutting parameters. Therefore, to acquire useful information for machining optimization is possible through process monitoring: the input data can be analyzed, processed and made available to optimize the process parameters in order to reduce critical issues such as the delamination, the fragmentation and the thermal damage. The present work deals with the problem of damage due to the high temperatures reached during the FRP dry drilling process. The temperature was measured by K type thermocouples positioned in the workpiece, near the hole surface, and it was evaluated as a function of the main process parameters in order to estimate the critical cutting conditions that lead to critical temperature overcoming

Validation and Testing of an Analytical Formulation to Compute the Reduction Factor in MV Grids

Global Earthing Systems (GESs) are defined by International Standards IEC 61936-1 and EN 50522 as an equivalent Earthing System (ES) created by the interconnection of local ESs. Thanks to this interconnection, just a percentage of the total fault current is injected to ground in a single ES, reducing the risk of electrocution. However, even if several experiments and models proved this effect, the identification and official certification is still a difficult task. Dangerous scenarios caused by a single-line-to-ground fault can be easily evaluated for a specific MV feeder by measurement or analytic models (quite cumbersome to use), but operative procedures valid for all the scenarios are still not available. In this work, a simplified formula to compute the reduction factor is presented, as well as its rationale. The proposed formula is easy to use and the results provided are sufficiently accurate, taking into account a desired safety margin. For this reason, it could be a valid tool for Distributor System Operators (DSO) and Certification Bodies and a step forward for the GES identification. The proposed formula is finally tested on three study cases

Una gerarchia delle magistrature civiche in Egitto? Tipologie di fonti e criteri di analisi

The present paper deals with the long discussed question of the hierarchy of municipal offices in Roman Egypt (2nd–3rd century A.D.). It focuses on methodological issues. Firstly, in dealing with honorary magistracies one should distinguish prestige (axioma) from the financial burden and the actual administrative role. Secondly, honorific titulatures, epistolary prescripts and municipal accounts should be examined according to different analysis criteria. In this way one can shed some light on the problem of preminence of the gymnasiarch or of the exegetes among municipal archai

Along strike preorogenic thickness variation and onlapping geometries control on thrust wedge evolution: insight from sandbox analogue modelling

Abstract: Thickness variation of sedimentary sequences is largely viewed as a controlling factor on the evolution of orogenic wedges; among the different structural and stratigraphic features generating thickness variation, we focused our analysis on the onlapping geometries, using laboratory sandbox experiments. The aim was trying to describe how a common sedimentary configuration could influence thrusts geometry and mode of accretion. Model results showed that onlapping geometries in pretectonic sediments cause a great complexity, dominated by curvilinear thrusts, back thrust and out-ofsequence thrusts. They also influence mode of accretion, generating diachronous thrusting along strike, reactivation and under-thrusting alternating to simple piggy-back sequence. Our modeling results are compared with natural examples from the Apennines, the southern Pyrenees, the Pindos (Greece) and the West Spitsbergen (Greenland) fold and thrust belts, among many others, where strain localization and diachronic thrusting affecting thrust propagation in correspondence to complex geometries both in the pre-orogenic stratigraphy and in the upper crust

Challenges and opportunities for more efficient water use and circular wastewater management. The case of Campania Region, Italy

By 2050, global demand for water is expected to increase by some 55% due to population growth and urbanization. The utilization of large amounts of freshwater in the world, generate huge volumes of wastewater of which, globally, more than 80% is discharged without treatment, thus causing impacts on aquatic ecosystems, human health and economic productivity. More sustainable practices of wastewater management are expected as a way towards circular bioeconomy (CBE) processes, whose goal is to implement closed systems promoting the systematic use of recycling, reuse and recovery of bioproducts and by-products and the reduction of waste generation. This approach, if adopted in the water and wastewater sector, can ensure environmental, economic and social benefits. The reuse of wastewater, on the one hand, reduces the volume of wastewater and the pressure on water bodies; on the other hand, the recovery of nutrients (P or N) and/or other high value bioproducts (biogas, cellulose, biopolymers) from wastewater offers numerous advantages in terms of supplying new raw bio-based materials that can be refed back to supply chains (thus substituting fossil resources) and, at the same time, producing cleaner water to be reused. Nevertheless, while in Europe many industries have demonstrated the ability to recycle and reuse water, in many regions of Italy the sustainable management of water and wastewater is not yet consolidated. In this study we explore the available technological, economic and environmental options concerning water use and wastewater treatment and we apply them to design appropriate scenarios for improved use efficiency and circular management. A comprehensive literature review of the most promising wastewater treatment processes for resources and energy valorization was conducted. The recovery of PHAs, struvite, nitrogen and algal biomass, as potential substitutes for conventional PET, phosphate and nitrogen chemical fertilizers and electricity, respectively, in addition to reusable treated water, were hypothesized and carefully discussed. Resulting scenarios are tested against the present situation of Campania Region (situated in Southern Italy) based on population and demand statistics, in order to develop strategies and policies potentially applicable locally and elsewhere

On the origin of X-shaped radio-sources: new insights from the properties of their host galaxies

A significant fraction of extended radio sources presents a peculiar X-shaped radio morphology: in addition to the classical double lobed structure, radio emission is also observed along a second axis of symmetry in the form of diffuse wings or tails. We re-examine the origin of these extensions relating the radio morphology to the properties of their host galaxies. The orientation of the wings shows a striking connection with the structure of the host galaxy as they are preferentially aligned with its minor axis. Furthermore, wings are only observed in galaxies of high projected ellipticity. Hydrodynamical simulations of the radio-source evolution show that X-shaped radio-sources naturally form in this geometrical situation: as a jet propagates in a non-spherical gas distribution, the cocoon surrounding the radio-jets expands laterally at a high rate producing wings of radio emission, in a way that is reminiscent of the twin-exhaust model for radio-sources.Comment: 7 pages, 6 figures, 1 table, accepted for publication in A&

Imaging and monitoring in minimally invasive valve surgery using an intra-aortic occlusion device: A single center experience

Background: Minimally invasive approach through a right mini-thoracotomy is a world-wide used procedure for mitral valve surgery. We performed a retrospective analysis based on our center experience in order to propose an effective, safe and reproducible method using an intra-aortic occlusion device.Methods: This is a retrospective analysis on 48 consecutive patients undergoing mitral valve surgery through a right anterolateral mini-thoracotomy in our center. An intra-aortic occlusion device was used for aortic clamping and cardioplegia delivery. Simultaneous multi-plane three-dimensional echocardiography imaging was acquired to detect the venous cannulas position, the intra-aortic device location in the ascending aorta, the balloon inflation, the complete occlusion of the aorta, the cardioplegia delivery, the origin and the blood flow in the right coronary artery. Aortic root pressure was measured by the tip of the intra-aortic occlusion device. A bilateral upper extremity invasive arterial pressure monitoring was detected. Neuromonitoring was performed through bilateral cerebral oximetry.Results: The analysis has shown no aortic dissection, neurological damage type 1 and myocardial ischemia in the study population. In 3 cases a distal displacement of the intra-aortic occlusion device was promptly detected by the combined use of echocardiographic imaging and by a drop of the right cerebral oximetry saturation and of the right radial artery pressure.Conclusions: The combined use of transesophageal simultaneous multi- plane three- dimensional echocardiography imaging, bilateral upper extremity invasive arterial pressure monitoring, aortic root pressure and cerebral oximetry is an effective, safe and reproducible method in patients undergoing minimally invasive valve surgery using an intra-aortic occlusion device