1,721,134 research outputs found
Hybridization of training aircraft with real world flight profiles
No full textPurpose The purpose of this paper is to analyze real-world flight data of a piston engine training aircraft collected from an internet-based radar service, along with wind data provided by a weather forecast model, and to use such data to design a hybrid electric power system. Design/methodology/approach The modeling strategy starts from the power demand imposed by a real-world wind-corrected flight profile, where speed and altitude are provided as functions of time, and goes through the calculation of the efficiency of the powertrain components when they meet such demand. Each component of the power system and, in particular, the engine and the propeller, is simulated as a black box with an efficiency depending on the actual working conditions. In the case of hybrid electric power system, the battery charging and discharging processes are simulated with the Shepherd model. Findings The variability of power demand and fuel consumption for a training aircraft is analyzed by applying the proposed methodology to the Piper PA-28-180 Cherokee, a very popular aircraft used for flight training, air taxi and personal use. The potentiality of hybridization is assessed by analyzing the usage of the engine over more than 90 flights. A tentative sizing of a hybrid electric power system is also proposed. It guarantees a fuel saving of about 5%. Originality/value The scientific contribution and the novelty of the investigation are related to the modeling methodology, which takes into account real-world flight conditions, and the application of hybridization to a training aircraft
Premessa
No full textIl contributo offre un profilo, umano e intellettuale, di Carlo Ferdinando Russo, docente di Letteratura greca nell'Università dei Bari e direttore di Belfagor
Fisiopatologia del circolo cerebrale
No full textAutoregulation of the cerebral circulation is the key mechanism that
keeps CBF constant within wide limits of arterial pressure. The
mechanism for autoregulation and the influence of arterial hypertension
and extracranial carotid stenosis are discussed. Brain function and
metabolism are critically dependent on sufficient CBF and oxygen supply.
Cerebral ischemia occurs when flow drops below about 10-15 ml/100 g/min.
Metabolic and therapeutic aspects of acute cerebral ischemia are
discussed
Tumefactive demyelinating lesions in patients with relapsing remitting multiple sclerosis treated with fingolimod
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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