Alleviating a form of electric vehicle range anxiety through On-Demand vehicle access

On-demand vehicle access is a method that can be used to reduce types of range anxiety problems related to planned travel for electric vehicle owners. Using ideas from elementary queueing theory, basic QoS metrics are defined to dimension a shared fleet to ensure high levels of vehicle access. Using mobility data from Ireland, it is argued that the potential cost of such a system is very low

Brain homeostasis : VEGF receptor 1 and 2 ; two unequal brothers in mind

Vascular endothelial growth factors (VEGFs), initially thought to act specifically on the vascular system, exert trophic effects on neural cells during development and adulthood. Therefore, the VEGF system serves as a promising therapeutic target for brain pathologies, but its simultaneous action on vascular cells paves the way for harmful side effects. To circumvent these deleterious effects, many studies have aimed to clarify whether VEGFs directly affect neural cells or if the effects are mediated secondarily via other cell types, like vascular cells. A great number of reports have shown the expression and function of VEGF receptors (VEGFRs), mainly VEGFR-1 and -2, in neural cells, where VEGFR-2 has been described as the major mediator of VEGF-A signals. This review aims to summarize and compare the divergent roles of VEGFR-1 and -2 during CNS development and homeostasis

Graphical statistics to explore the natural and anthropogenic processes influencing the inorganic quality of drinking water, ground water and surface water

Plots of cumulative distribution functions (CDF) are a simple but powerful exploratory data analysis (EDA) tool to evaluate and compare statistical data distributions. Here, empirical CDF plots are used to compare results of four large (476 to 884 samples) national- to continental-scale inorganic water chemistry data sets: (1) European surface water, (2) European tap water, (3) European bottled waters as a proxy for groundwater and (4) Norwegian crystalline bedrock rock groundwater, all analysed at the same laboratory, albeit at different times. For many parameters (e.g., Ba, Cl-, K, SO4 2-) median values and ranges are, given the differing origins and, in some cases, treatment processes of the waters, surprisingly comparable. Unusually high concentrations of some other elements (e.g., B, Be, Br, Cs, F-, Ge, Li, Rb, Te and Zr) appear to be characteristic of deeper-seated, mature groundwaters. Other influences that can be inferred include contamination from well construction or plumbing materials (Cu, Pb, Zn – in tap waters, bottled waters and Norwegian groundwaters), water treatment (Fe, Mn – in tap- and Norwegian groundwater), bottle materials (Sb - bottled waters). The empirical CDF plots also reveal analytical issues for some elements (excessive rounding, element interferences). The best reference for natural and uncontaminated ’water’ is probably provided by the mineral water samples, representing ’deep groundwater’ at the European scale

Energy barriers in three-dimensional micromagnetic models and the physics of thermoviscous magnetization

This article has been accepted for publication in Geophysical Journal International © 2018. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Source at https://doi.org/10.1093/gji/ggy285.A first-principle micromagnetic and statistical calculation of viscous remanent magnetization (VRM) in an ensemble of cubic magnetite pseudo-single domain (PSD) particles is presented. The theoretical methods developed apply to all magnetic particle sizes, from single domain to multidomain. The numerical implementation is based on a fast relaxation algorithm for finding optimal transition paths between micromagnetic local energy minima. The algorithm combines a nudged-elastic-band technique with action minimization. Initial paths are obtained by repetitive minimizations of modified energy functions. For a cubic PSD particle, 60 different local energy minima are identified, and all optimal energy barriers between them are numerically calculated for the case of zero external field. These results are used to estimate the energy barriers in weak external fields. Based on these, time-dependent transition matrices are constructed, which fully describe the continuous homogeneous Markov processes of VRM acquisition and decay. By spherical averaging, the acquisition of remanent magnetization in an isotropic PSD ensemble is calculated from laboratory to geological timescales. The modelled particle ensemble shows a physically meaningful overshooting of magnetization during VRM acquisition. The results also clarify why VRM acquisition in PSD particles can occur much faster than VRM decay, and therefore explain occurrence of extremely stable VRM as found in some palaeomagnetic studies

Design and regulation of balancing power auctions: an integrated market model approach

We present an integrated market model which considers the dependencies between the wholesale market and the highly regulated balancing power markets. This fosters the understanding of the mechanisms of these markets and, thus, allows the evaluation of the designs of these markets and their interplay. In contrast to existing literature, in our model the prices on the different markets are interdependent and endogenously determined, which also applies to the switch from inframarginal suppliers to extramarginal suppliers. Linked to this, the implementation of a specific assignment of the suppliers to the different markets is according to their production costs and their ability to provide balancing power. We prove the existence of a market equilibrium, analyze its outcome and contrast this with German market data. Based on this model, we assess design changes, partly stipulated by recent European regulation. This includes uniform pricing as a common settlement rule (effect: no truthful bidding in general), standardized prequalification criteria (promising measure for cost reduction), market flexibilization via “free energy bids” (no increased competition) and the alternative score “mixed-price rule” (no effect on the equilibrium)