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Quantitative characterisation of the trajectories of moving animals is an important component of many behavioural and ecological studies, however methods are complicated and varied, and sometimes require well‐developed programming skills to implement. Here, we introduce trajr, an R package that serves to analyse animal paths, from unicellular organisms, through insects to whales. It makes a variety...
Magnetic field wireless power transfer (WPT) systems for vehicular applications are rapidly becoming standardized in order to facilitate interoperability. One somewhat unconventional coupler (winding assembly) design, the DD topology, has been shown to provide good performance in terms of efficiency, maximum separation, and tolerance to misalignment. However, the extraneous electromagnetic field of...
The minimum phase property is of interest in broadband antennas, particularly pulse-forming antennas, because it determines whether it is feasible to perform broadband equalization of the antenna transfer function. We show that directional aperture antennas lose the minimum phase property at angles significantly off boresight, and give some simple analytical expressions for the angles within which...
Because efficiency is paramount, magnetic field wireless power transfer (MF-WPT) systems are tuned in a manner similar to some tuned linear transformers, such as IF transformers, in which the primary and secondary circuits are each tuned to the same resonant frequency (synchronous tuning) and then the load resistance adjusted for critical coupling. This causes the primary and secondary currents to...
The treatment of patients with metastatic colorectal cancer (mCRC) has evolved during the past 2 decades, and patient survival has increased. Consequently, patients are exposed to more chemotherapeutic agents and regimens. Little is known about therapeutic drug sequencing and the factors influencing these choices.An observational, retrospective medical record review was conducted of patients with...
Magnetic Field Wireless Power Transfer (MF-WPT) systems typically employ ferrite cores in order to improve magnetic coupling and minimize the extraneous field. The size of the couplers and hence the ferrite cores for an MF-WPT system are determined to a large part by the separation. The shape of the core is important in minimizing the extraneous magnetic flux. However, large, custom ferrite parts...
The extra element theorem is applied to the optimal design of impedance loaded electrically-small antennas. The applicability of the extra element theorem includes active and non-Foster loading. A key component of the framework of the extra element theorem termed null-double injection is shown to provide a direct and quantitative determination of the efficacy of a particular loading point.
The Van Veen loop is intrinsically well adapted to time-domain measurements of net magnetic dipole moment. That is, the system comes very close to preserving the shape of the time-domain waveform of the net or residual magnetic dipole moment produced by the DUT. This property makes the Van Veen Loop very useful in the characterization of magnetic field wireless power transfer systems in which short-time-scale...
Magnetic field wireless power transfer (MF-WPT) systems for the charging of hybrid and electric vehicle batteries constitute an emerging technology and one which is being rapidly standardized by several international organizations such as IEC, JARI and SAE. Recent global harmonization efforts tend to favor a fundamental charging operation centered at frequencies around 85 kHz, which lies in the LF...
Magnetic Field Wireless Power Transfer (MF-WPT) is appropriate for high-power applications such as the charging of electric vehicle batteries. Most systems operate essentially as resonant converters with the couplers (primary and secondary windings) and matching networks absorbed into the tank circuit of a resonant converter topology. As in a well-designed resonant converter, the currents in the couplers...
A generalized, linear atlgorith m is used for unbiasrd quantification of the orientation of corneal collagen fibers. Its application to SHG microscopy for determining macro structure urthe collagen extracellular matrix is demonstrated.
Omni-directional, log-periodic antennas are relatively uncommon, but nevertheless some implementations have previously been described. Also, so-called clamped-mode, log-periodic structures which provide greater bore-sight gain by employing linear elements substantially longer than one-half wavelength have been described in the patent literature. Here we show how an omni-directional, clamped-mode log-periodic...
Practical implementations of the Van Veen Loop, or Large Loop Antenna (LLA), necessarily contain imperfections, especially those due to finite mechanical tolerances. We examine the effects on performance of non-commensurate constituent transmission lines and unequal terminating resistors in the internal network of an LLA. It is shown that the electric field rejection of the LLA is somewhat insensitive...
The secondary side of an inductive power transfer (IPT) system is typically galvanically isolated. In IPT systems for vehicular applications, the vehicle is isolated from earth ground by the tires. The primary side is necessarily and in accordance to regulations grounded. The electric field of an IPT system is intense and IPT systems usually employ an electrostatic shield between the secondary coupler...
The region immediately behind the active region of a log-periodic dipole antenna (LPDA), the stop region, is investigated. In compressed LPDAs, in which one or both of the LPDA parameters are reduced, the attenuation coefficient of the stop region is strongly dependent on the unloaded characteristic impedance of the feed transmission line, and the stop region can fail to confine the incident power...
We investigate the balancing efficacy of the "infinite" balun using a numerical simulation of a log periodic dipole antenna fed from a coaxial source via an infinite balun. The simulation enables the accurate representation of the coaxial source and the computation of the current on the two conductors of the feed transmission line. We show that the infinite balun feed arrangement results...
The Van Veen Loop, Large Loop Antenna (LLA), or Loop Antenna System (LAS), provides rapid determination of the net magnetic dipole moment of compact devices, especially in the frequency range of 9 kHz to 30 MHz, with minimal post processing of measured data. The symmetric shielded loop structure inherently rejects electric field excitation to a large extent if the action of the current transformer...
A comparison is made between the mixed lumped and distributed equivalent two-port networks for spherical modes, as derived by Thal, and the mixed lumped and distributed equivalent networks for certain classes of nonuniform transmission lines, as derived by Kobayashi. The extended Kuroda transform is used to derive a model for dipolar (radial index of 2) spherical mode propagation consisting of a nonuniform...
The q uasi-static near magnetic field of an inductive power transfer system would be expected to be intense. However, the quasi-static near electric field is also quite intense and merits investigation. As for any vector field, the near electric field can be decomposed into conservative and solenoidal components. The solenoidal component is the one that would be anticipated from Faraday's law. However,...
Inductive power transfer (IPT) is a subset of contactless power transfer appropriate for high-power applications such as the charging of electric vehicle batteries. Previous work has considered primarily the magnetostatic far field, that is, the region well away from the couplers in terms of coupler dimensions, but still close to the couplers in terms of the wavelength of the radiated field. The nature...
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