6 research outputs found

    Analyzing transients on multiconductor lines with corona

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    This paper describes a line model which is intended for analyzing transients on multi-conductor lines with corona. This model is based on the method of characteristics from the theory of partial differential equations. It accounts for the facts that line modes depend on the conductor voltages and that the modes do not superpose linearly. The proposed model is applied in the simulation of a field experiment Comparisons are made between simulated and measured waveforms. Also a comparison is made against a simulation with a single-phase line model. The results attained with the model proposed here are very encouraging. Zapotitlán2004 IEEE

    A conservation law consistent updated Lagrangian material point method for dynamic analysis

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    The Material Point Method (MPM) is well suited to modelling dynamic solid mechanics problems undergoing large deformations with non-linear, history dependent material behaviour. However, the vast majority of existing material point method implementations do not inherit conservation properties (momenta and energy) from their continuum formulations. This paper provides, for the first time, a dynamic updated Lagrangian material point method for elasto-plastic materials undergoing large deformation that guarantees momenta and energy conservation. Sources of energy dissipation during point-to-grid and grid-to-point mappings for FLuid Implicit Particle (FLIP) and Particle In Cell (PIC) approaches are clarified and a novel time-stepping approach is proposed based on an efficient approximation of the Courant-Friedrich-Lewy (CFL) condition. The formulation provided in this paper provides a platform for understanding the energy conservation nature of future/existing features of material point methods, such as contact approaches

    Do Spatial Designs Outperform Classic Experimental Designs?.

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    Controlling spatial variation in agricultural field trials is the most important step to compare treatments efficiently and accurately. Spatial variability can be controlled at the experimental design level with the assignment of treatments to experimental units and at the modeling level with the use of spatial corrections and other modeling strategies. The goal of this study was to compare the efficiency of methods used to control spatial variation in a wide range of scenarios using a simulation approach based on real wheat data. Specifically, classic and spatial experimental designs with and without a twodimensional autoregressive spatial correction were evaluated in scenarios that include differing experimental unit sizes, experiment sizes, relationships among genotypes, genotype by environment interaction levels, and trait heritabilities. Fully replicated designs outperformed partially and unreplicated designs in terms of accuracy; the alpha-lattice incomplete block design was best in all scenarios of the medium-sized experiments.However, in terms of response to selection, partially replicated experiments that evaluate large population sizes were superior in most scenarios. The AR1×AR1 spatial correction had little benefit in most scenarios except for the medium-sized experiments with the largest experimental unit size and low GE. Overall, the results from this study provide a guide to researchers designing and analyzing large field experiments. Supplementary materials accompanying this paper appear online

    Position Paper on Global Extracorporeal Membrane Oxygenation Education and Educational Agenda for the Future: A Statement From the Extracorporeal Life Support Organization ECMOed Taskforce*

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    Objectives:The purpose of this position paper is two-fold: first, to describe the state of extracorporeal membrane oxygenation education worldwide, noting current limitations and challenges; and second, to put forth an educational agenda regarding opportunities for an international collaborative approach toward standardization.Design:Relevant medical literature was reviewed through literature search, and materials from national organizations were accessed through the Internet. Taskforce members generated a consensus statement using an iterative consensus process through teleconferences and electronic communication.Setting:In 2018, the Extracorporeal Life Support Organization convened the ECMOed Taskforce at two structured, face-to-face meetings of 40 healthcare practitioners and educators with expertise in caring for the extracorporeal membrane oxygenation patient and in extracorporeal membrane oxygenation education.Patients:None.Interventions:None.Measurements and Main Results:The ECMOed Taskforce identified seven educational domains that would benefit from international collaborative efforts. Of primary importance, the Taskforce outlined actionable items regarding 1) the creation of a standardized extracorporeal membrane oxygenation curriculum; 2) defining criteria for an extracorporeal membrane oxygenation course as a vehicle for delivering the curriculum; 3) outlining a mechanism for evaluating the quality of educational offerings; 4) utilizing validated assessment tools in the development of extracorporeal membrane oxygenation practitioner certification; and 5) promoting high-quality educational research to guide ongoing educational and competency assessment development.Conclusions:Significant variability and limitations in global extracorporeal membrane oxygenation education exist. In this position paper, we outline a road map for standardizing international extracorporeal membrane oxygenation education and practitioner certification. Ongoing high-quality educational research is needed to evaluate the impact of these initiatives.Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care
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