2,584 research outputs found
Isogeometric Analysis in advection-diffusion problems: tension splines approximation
We present a novel approach, within the new paradigm of isogeometric analysis
introduced by Hughes et al., to deal with advection dominated
advection-diffusion problems. The key ingredient is the use of Galerkin approximating
spaces of functions with high smoothness, as in IgA based on
classical B-splines, but particularly well suited to describe sharp layers involving
very strong gradients
Construction of planar quintic Pythagorean-hodograph curves by control-polygon constraints
In the construction and analysis of a planar Pythagorean–hodograph (PH) quintic curve r(t), t∈[0,1] using the complex representation, it is convenient to invoke a translation/rotation/scaling transformation so r(t) is in canonical form with r(0)=0, r(1)=1 and possesses just two complex degrees of freedom. By choosing two of the five control–polygon legs of a quintic PH curve as these free complex parameters, the remaining three control–polygon legs can be expressed in terms of them and the roots of a quadratic or quartic equation. Consequently, depending on the chosen two control–polygon legs, there exist either two or four distinct quintic PH curves that are consistent with them. A comprehensive analysis of all possible pairs of chosen control polygon legs is developed, and examples are provided to illustrate this control–polygon paradigm for the construction of planar quintic PH curves
Phase Centre Optimization in Profiled Corrugated Circular Horns with Parallel Genetic Algorithms
Experimental Investigation of Fast−Charging Effect on Aging of Electric Vehicle Li−Ion Batteries
A huge increase in fast−charging stations will be necessary for the transition to EVs. Nevertheless, charging a battery pack at a higher C−rate impacts its state of health, accelerating its degradation. The present paper proposes a different and innovative approach that considers the daily routine of an EV Li−ion battery based on a standard driving cycle, including charging phases when the depth of discharge is 90%. Through dynamic modeling of the EV battery system, the state of charge evolution is determined for different charging C−rates, considering both real discharging and charging current profiles. Finally, by applying a suitable post−processing procedure, aging test features are defined, each being related to a specific EV battery working mode, including charging at a particular C−rate, considering the global battery operation during its lifespan. It is demonstrated that, according to the implemented procedure, fast−charging cycles at 50 kW reduce battery lifespan by about 17% with respect to charge in a 22 kW three−phase AC column, in parity with the discharge rate. Thus, this work can provide a deep insight into the expected massive penetration of electric vehicles, providing an estimate of battery useful life based on charging conditions
High Gain Compact Strip and Slot UWB Sinuous Antennas
Three ground-backed compact strip-and slot-sinuous antennas are analyzed. Proposed configuration allows for a single lobe, polarization-versatile, high efficiency, and ultrawide band antenna not needing a cumbersome lossy back cavity typical of conventional single-lobe sinuous antennas. Simulations show attained performances as well as tuning possibilities
Health Care Resource Utilization Costs Related to Anaemia Management in Chronic Kidney Disease Non-Dialysed Patients: A Retrospective Clinical and Administrative Database Analysis
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Effects of artificial changes in chest wall compliance on respiratory mechanics and gas exchange in patients with acute lung injury (ALI)
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