Search results for " Transient"

Frequency dynamics of power systems with temporally distributed disturbances

2021

Abstract The frequency dynamics and stability of power systems is essentially affected by nature and characteristics of the disturbances occurring in the system. Conventionally, frequency transients are examined assuming a single disturbance applied at a given time. However, actual incidents in the power systems can be generally composed of a temporal sequence of events, and thus characterized by multiple power imbalances of different magnitudes and time offsets. The consideration of the effects of the temporal distribution of power imbalances is important for two main reasons: the impact on the frequency dynamics of the system in terms of frequency metrics such as minimum instantaneous fre…

Long-term performance of the bovine pericardium patch in conventional carotid endarterectomy.

2014

Objective The aim of the study was to analyze long-term results of carotid endarterectomy (CEA) using bovine pericardium patch. Patients and Methods This study is a retrospective analysis of 274 consecutive cases (173 in CEA group and 101 patients in an internal control group of eversion endarterectomy [EEA]) operated between January 2005 and May 2007. Operations were performed according to standard surgical technique. Primary endpoints of the study were 30-day mortality, ipsilateral neurologic event rate, and high-grade restenosis in the long-term follow-up. Results No statistically significance between both groups was found in terms of gender, age, risk factors, medication (statine, plate…

Application of latent class analysis in assessing the awareness, attitude, practice and satisfaction of paediatricians on sleep disorder management i…

2020

Aim To identify subgroups regarding paediatricians’ awareness, attitude, practice and satisfaction about management of Sleep-Disordered Breathing (SDB) in Italy using Latent Class Analysis (LCA). Methods A cross-sectional study was conducted on a large sample of Italian paediatricians. Using a self-administered questionnaire, the study collected information on 420 Paediatric Hospital Paediatricians (PHPs) and 594 Family Care Paediatricians (FCPs). LCA was used to discover underlying response patterns, thus allowing identification of respondent groups with similar awareness, attitude, practice and satisfaction. A logistic regression model was used to investigate which independent variables i…

Incidence and prognostic factors related to major adverse cerebrovascular events in patients with complex aortic diseases treated by the chimney tech…

2018

Abstract Objective Endovascular aneurysm repair (EVAR) with the chimney technique (ch-EVAR) has been used for the treatment of aortic aneurysms as an alternative approach to fenestrated endografting or open repair. Nonetheless, the need for an upper extremity arterial access may contribute to a higher risk for periprocedural cerebrovascular events. This study reports on the perioperative cerebral and major adverse cardiac and cerebrovascular events (MACCE) after ch-EVAR. Methods The PERICLES registry (PERformance of the chImney technique for the treatment of Complex aortic pathoLogiES) is an international, retrospective multicenter study evaluating the performance of ch-EVAR for the treatme…

3D Data Acquisition and Numerical Analysis of a Footwear in Walking

2004

The aim of the paper is to set a procedure to study the load history of a footwear during a step with non-linear FE analysis. The geometric model tested was reconstructed from a real shoe by means of Reverse Engineering process, starting from dense point clouds acquired by non-contact scanning system. For each phase of the walk, the pressure values are obtained by a pressure distribution platform when tester is walking along the platform. The Finite Element model is easily generated by Hypermesh software using the CAD model. Ansys software is used to perform non-linear analyses. The procedure can be employed for improving the product performance in terms of durability, flexibility and comfo…

On the transient response of actively repaired damaged structures by the boundary element method

2010

The transient fracture mechanics behavior of damaged structures repaired through active piezoelectric patches is presented in this paper. The analyses have been performed through a boundary element code implemented in the framework of piezoelectricity to take account of the coupling between the elastic and the electric fields, which represents the peculiar feature of piezoelectric media. The multi-domain technique has been also involved to assemble the host structures and the active patches and to model the cracks. Moreover, the patches have been considered elastically bonded to the damaged structure by means of a zero thickness adhesive layer. This has been achieved through the implementat…

A combined CWT-DWT method using model-based design simulator for partial discharges online detection

2009

The suppression of noises is fundamental in onsite Partial Discharge (PD) measurements. For this purpose, the wavelet transform analysis method has been developed and it is a powerful tool for processing the transient and suddenly changing signals. As the wavelet transform possesses the properties of multi-scale analysis and time-frequency domain localization, it is also particularly suitable to process the suddenly changing signals of the partial discharge pulse (PD). In this paper, an improved Wavelet denoising method developed by a model-based design software is presented. Simulations are provided as well as some results obtained during laboratory experiment and on-line PD measurements. …

Differential diagnosis of vascular necrosis of the femoral head (AVN) and transient hip osteoporosis (THO): role of MRI

2014

Chemosensory Receptors in the Larval Maxilla of Papilio hospiton

2022

Among the butterflies of the genus Papilio (Lepidoptera: Papilionidae), Papilio hospiton (Géné) has a geographical distribution limited to the Mediterranean islands of Sardinia (Italy) and Corsica (France). This is mainly due to the host range that includes only a few plant species of Apiaceae and Rutaceae growing on these islands. In a previous electrophysiological investigation conducted on the maxillary gustatory system of larvae of P. hospiton and its closely phylogenetically related species Papilio machaon, a significantly higher spike activity was shown for the gustatory neurons of lateral and medial styloconic sensilla in P. hospiton when bitter compounds were tested. This effect was…

On the thermomechanical behavior of the European target assembly design of IFMIF-EVEDA lithium test loop under start-up transient scenarios

2013

Uncoupled thermomechanical transient analyses have been carried out to investigate the behavior of IFMIF-EVEDA lithium test loop bayonet backplate target assembly under two selected start-up transient operational scenarios. The first transient scenario considered foresees that the target assembly, starting from the initial uniform temperature of 50 C, is heated up uniquely by convective heat transfer with lithium, flowing from inlet to outlet nozzle at its reference nominal temperature and pressure, until its nominal steady state thermal field distribution is reached. The second transient scenario foresees, more realistically, that the target assembly, starting from the uniform temperature …