Search results for "Transient"
showing 10 items of 623 documents
Steady state and transient thermal–hydraulic analyses on ITER divertor module
2005
Abstract One of the most challenging components of ITER is the divertor devoted at controlling the characteristics of the plasma boundary, exhausting the α particles and reducing the impurities in the plasma. The thermal–hydraulic design of the divertor is particularly, demanding because of the high heat loads and the cooling flow margin in the plasma-facing components (PFCs). The pressure drop is limited by the pumping power and also avoiding the risk of reaching critical heat flux (CHF). Furthermore, for maintenance operation foreseen, each single divertor cassette should be drained and dried before withdrawing it out from the vacuum vessel. To address these requirements, European Fusion …
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…
Fast Photochemistry of Prototypical Phytochromes—A Species vs. Subunit Specific Comparison
2015
Phytochromes are multi-domain red light photosensor proteins, which convert red light photons to biological activity utilizing the multitude of structural and chemical reactions. The steady increase in structural information obtained from various bacteriophytochromes has increased understanding about the functional mechanism of the photochemical processes of the phytochromes. Furthermore, a number of spectroscopic studies have revealed kinetic information about the light-induced reactions. The spectroscopic changes are, however, challenging to connect with the structural changes of the chromophore and the protein environment, as the excited state properties of the chromophores are very sens…
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…
Transient color centers in complex oxide crystals
2005
The present work is devoted to investigation of induced by a pulsed electron beam (E = 0.25 MeV, τ = 10 ns) transient color centers in pure Gd3Ga5O12, YAlO3 and LiNbO3 single crystals. The relaxation of induced absorption of the crystals was studied within 0-5000 ns range. The origin and nature of transient color centers responsible for induced absorption was discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
SPICE model for resistive gas and odour sensors
1999
A generalised PSPICE model of resistive gas/odour sensors is presented. The model simulates the response of both polymeric and metal oxide devices, as well as an integrated resistive heater that is used to set the operating temperature. In both cases there was good agreement between the observed responses and the PSPICE simulated responses to rectangular pulses of gases. The PSPICE model is not only simpler and faster to use than analytical solutions, but also should permit the rapid prototyping of associated drive circuitry.
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…
A Constrained Optimal Model Predictive Control for Mono Inverter Dual Parallel PMSM Drives
2018
The actual trends in the design of AC drives are directed to the reduction of the total weight, volume and cost. Usually, this implies the necessity to adopt new motor topologies and converter architectures. An important role is played by the mono-inverter dual parallel motor (MIDP), which gives the possibility to reduce the total weight and costs of power converters. This paper proposes a novel model predictive control algorithm in order to improve the transient performances of a MIDP used for an overhead carrier. The effectiveness of the proposal control is verified through some numerical simulations.
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…