On the reliability of electrical drives for safety-critical applications

The aim of this work is to present some issues related to fault tolerant electric drives,which are able to overcome different types of faults occurring in the sensors, in thepower converter and in the electrical machine, without compromising the overallfunctionality of the system. These features are of utmost importance in safety-criticalapplications. In this paper, the reliability of both commercial and innovative driveconfigurations, which use redundant hardware and suitable control algorithms, will beinvestigated for the most common types of fault: besides standard three phase motordrives, also multiphase topologies, open-end winding solutions, multi-machineconfigurations will be analyzed, applied to various electric motor technologies. Thecomplexity of hardware and control strategies will also be compared in this paper, sincethis has a tremendous impact on the investment costs

Antioxidant Supplementation in the Treatment of Aging-Associated Diseases

Oxidative stress is generally considered as the consequence of an imbalance between pro- and antioxidants species, which often results into indiscriminate and global damage at the organismal level. Elderly people are more susceptible to oxidative stress and this depends, almost in part, from a decreased performance of their endogenous antioxidant system. As many studies reported an inverse correlation between systemic levels of antioxidants and several diseases, primarily cardiovascular diseases, but also diabetes and neurological disorders, antioxidant supplementation has been foreseen as an effective preventive and therapeutic intervention for aging-associated pathologies. However, the expectations of this therapeutic approach have often been partially disappointed by clinical trials. The interplay of both endogenous and exogenous antioxidants with the systemic redox system is very complex and represents an issue that is still under debate. In this review a selection of recent clinical studies concerning antioxidants supplementation and the evaluation of their influence in aging-related diseases is analyzed. The controversial outcomes of antioxidants supplementation therapies, which might partially depend from an underestimation of the patient specific metabolic demand and genetic background, are presented

Proposed improvement of coastal habitat resilience: The case study of Pantano forest of Policoro in southern Italy

In the last decades, climate change and the rapid urbanization due to the development of the coastal economy have led to biodiversity loss and the fragmentation of habitat in many coastal zones. The presence of protected areas cannot prevent the progress of land degradation. However, these areas are very important because they provide significant ecosystem services and affect local tourism. With regard to increasing adaptation strategies to human pressures and climate change, the present study proposes a detailed monitoring activity and an ecological restoration plan which could improve the resilience of a protected coastal zone in the Pantano forest of Policoro, located on the Ionian coast (southern Italy). In this area, continuous phenomena of intensive deforestation, hydraulic reclamation actions, and fires have reduced the native species of particular naturalistic value, favouring the advancement of desertification, coastal erosion, and saltwater intrusion. The proposed actions are derived from a preliminary analysis on maps, UAV-images, climate data and from meetings with the local community. The operative process detailed in this article could be applied to other protected areas which are subjected to the same phenomena and problems

Bulk viscosity in 2SC and CFL quark matter

The bulk viscosities of two color-superconducting phases, the color-flavor locked (CFL) phase and the 2SC phase, are computed and compared to the result for unpaired quark matter. In the case of the CFL phase, processes involving kaons and the superfluid mode give the largest contribution to the bulk viscosity since all fermionic modes are gapped. In the case of the 2SC phase, ungapped fermionic modes are present and the process u+d u+s provides the dominant contribution. In both cases, the bulk viscosity can become larger than that of the unpaired phase for sufficiently large temperatures (T >~ 1 MeV for CFL, T >~ 0.1 MeV for 2SC). Bulk viscosity (as well as shear viscosity) is important for the damping of r-modes in compact stars and thus can potentially be used as an indirect signal for the presence or absence of color-superconducting quark matter.Comment: 8 pages, 3 figures, contribution to the proceedings of QCD@Work 2007, Martina Franca (Italy

Early Experience with the New Ovation Alto Stent Graft in Endovascular Abdominal Aortic Aneurysm Repair

Introduction: Since 2010, the Ovation Abdominal Stent Graft System has offered a new sealing concept, achieved by a sealing ring filled with polymer 13 mm from the renal arteries. In the latest version, called Ovation Alto, the sealing ring is relocated 6 mm closer to the top of the fabric. This study describes the early clinical outcomes, after CE Mark approval in August 2020, of endovascular aneurysm repair with the Alto endograft. Report: Eleven patients underwent endovascular aneurysm repair with implantation of Ovation Alto endografts. All patients were male, and the median age was 75 (IQR 5.5) years. Hostile proximal aortic neck (<10 mm) was identified in six cases (54.5%). All procedures were performed using bilateral percutaneous approaches with no groin complications. The median procedure time was 58 (IQR 7.2) minutes, the median contrast volume used was 65 (IQR 4.2) mL, and the median blood loss 40 (IQR 12.4) mL. Technical success was achieved in all cases. The median stent graft landing distance between the top of the fabric and the lowest renal artery was 1.4 (IQR 0.8) mm. No intra-operative high flow endoleaks were registered. At one and six month follow up, there was 100% clinical success (no type I/III endoleak, sac enlargement, stent graft migration, polymer leakage, abdominal aortic aneurysm related mortality, or secondary intervention). Discussion: Initial experience confirms the early technical and clinical success of the new Ovation Alto stent graft. Technical modifications to the endograft could allow for accommodation of a more comprehensive range of anatomies on label. Further studies are needed to evaluate long term durability outcomes

Analysis, modeling, and control of half-bridge current-source converter for energy management of supercapacitor modules in traction applications

In this work, an in-depth investigation was performed on the properties of the half-bridge current-source (HBCS) bidirectional direct current (DC)-to-DC converter, used to interface two DC-link voltage sources with a high-voltage-rating mismatch. The intended implementation is particularly suitable for the interfacing of a supercapacitor (SC) module and a battery stack in a hybrid storage system(HSS) for automotive applications. It is demonstrated that the use of a synchronous rectification (SR) modulation scheme benefits both the power-stage performance (in terms of efficiency and reliability) and the control-stage performance (in terms of simplicity and versatility). Furthermore, an average model of the converter, valid for every operating condition, is derived and utilized as a tool for the design of the control system. This model includes the effects of parasitic elements (mainly the leakage inductance of the transformer) and of the converter snubbers. A 3 kW prototype of the converter was used for experimental validation of the converter modeling, design, and performance. Finally, a discussion on the control strategy of the converter operation is included

Secondary Baryon Asymmetry in pi(+-)p Collisions

The process of secondary baryon production in pi(+-)p collisions at high energies in the central and forward fragmentation regions is considered in the framework of the Quark-Gluon String Model. The contribution of the string-junction mechanism to the baryon production is analysed. The results of numerical calculations are in reasonable agreement with the experimental data on the Lambda/bar(Lambda) and p/bar(p)$ asymmetries.Comment: Contribution to the Proceedings of QCD@Work 2007, International Workshop on Quantum Chromodynamics, Theory and Experiment, Martina Franca-Valle d'Itria, Italy, June 16-20, 2007 (6 pages and 4 figures

Optical Coherence Tomography after Carotid Stenting: Rate of Stent Malapposition, Plaque Prolapse and Fibrous Cap Rupture According to Stent Design

ObjectivesThis study aims to evaluate the rate of stent malapposition, plaque prolapse and fibrous cap rupture detected by optical coherence tomography (OCT) imaging according to carotid stent design.DesignIt was a prospective single-centre study.Materials and methodsForty consecutive patients undergoing protected carotid artery stenting (CAS) and high-definition OCT image acquisition were enrolled in the study. OCT frames were analysed off-line, in a dedicated core laboratory by two independent physicians. Cross-sectional OCT images within the stented segment of the internal carotid artery were evaluated at 1-mm intervals for the presence of strut malapposition, plaque prolapse and fibrous cap rupture according to stent design.ResultsClosed-cell design stents (CC) were used in 17 patients (42.5%), open-cell design stents (OC) in 13 (32.5%) and hybrid design stents (Hyb) in 10 (25%). No procedural or post-procedural neurological complications occurred (stroke/death 0% at 30 days). On OCT analysis the frequencies of malapposed struts were higher with CC compared to OC and Hyb (34.5% vs 15% and 16.3%, respectively; p < 0.01). Plaque prolapse was more frequent with OC vs CC (68.6% vs 23.3%; p < 0.01) and vs Hyb stents (30.8%; p < 0.01). Significant differences were also noted in the rates of fibrous cap rupture between CC and OC (24.2% vs 43.8%; p < 0.01), and between CC and Hyb (24.2% vs 39.6%; p < 0.01), but not between OC and Hyb stents (p = 0.4).ConclusionIntravascular OCT after CAS revealed that micro-defects after stent deployment are frequent and are related to the design of implanted stents. Stent malapposition is more frequent with CC stents, while plaque prolapse is more common with OC stents.It remains, however, unknown whether these figures now detected with OCT are of any clinical and prognostic significance