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Article Type: Research Article

Abstract: Background: Driving constitutes a very important aspect of daily life and is dependent on cognitive functions such as attention, visuo-spatial skills and memory, which are often compromised in dementia. Therefore, the driving fitness of patients with dementia needs to be addressed by physicians and those that are deemed unfit should not be allowed to continue driving. Objective: We aimed at investigating to what extent physicians assess driving fitness in dementia patients and determinant factors for revoking of their licenses. Methods: This study includes 15113 patients with newly diagnosed dementia and driver’s license registered in the Swedish Dementia Registry (SveDem). The …main outcomes were reporting to the licensing authority and making an agreement about driving eligibility with the patients. Results: Physicians had not taken any action in 16% of dementia patients, whereas 9% were reported to the authority to have their licenses revoked. Males (OR = 3.04), those with an MMSE score between 20–24 (OR = 1.35) and 10–19 (OR = 1.50), patients with frontotemporal (OR = 3.09) and vascular dementia (OR = 1.26) were more likely to be reported to the authority. Conclusion: For the majority of patients with dementia, driving fitness was assessed. Nevertheless, physicians did not address the issue in a sizeable proportion of dementia patients. Type of dementia, cognitive status, age, sex and burden of comorbidities are independent factors associated with the assessment of driving fitness in patients with dementia. Increased knowledge on how these factors relate to road safety may pave the way for more specific guidelines addressing the issue of driving in patients with dementia. Show more

Keywords: Dementia, Alzheimer’s disease, frontotemporal dementia, driving license, cognitive status, agreement

DOI: 10.3233/JAD-160254

Citation: Journal of Alzheimer's Disease, vol. 53, no. 2, pp. 631-638, 2016

Article Type: Research Article

Abstract: A novel compact microstrip patch circularly polarised antenna for mobile wireless application is presented in this paper. The proposed antenna is incorporated with quadrilateral shape radiator, inverted S-shape partial ground plane and 50 Ω microstrip feed line. A wide impedance bandwidth of 109.13% (1.69-5.75 GHz with measured 3 dB axial ratio (AR) bandwidth of 22.22% (2-2.5 GHz) is realized with overall electrical size of 0.26 λ × 0.21 λ × 0.01 λ at lower-end frequency. The antenna also exhibits good performance of circular polarization (CP) radiation with lower 3d B AR beamwidth of ± 60°. In addition, the specific absorption …rate of the presented antenna is analysed. Show more

Keywords: Antenna, circular polarization, wideband, wireless communication

DOI: 10.3233/JAE-150043

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 45-49, 2016

Article Type: Research Article

Abstract: Magnetrons are widely applied to the rapidly developing microwave industries as high power microwave sources. However, the free-running magnetron produces unstable frequency and wideband spectrum, which limits the magnetron's further applications for coherent power-combining and scientific fields. In this paper, by introducing a feedback loop with a high Q filter into the magnetron system, the output frequency can be qusai locked around the center frequency of the filter if the loop phase is between (2k-1 2 ) π and (2k+1 2 )π. Moreover, the output frequency bandwidth of the self-injection magnetron is narrowed and the phase noise is also reduced. …In order to find out the requirements for the qusai locked magnetron and the effects of the parameters on the qusai locked results, a theoretical model based on the combination of the equivalent circuit of the magnetron and the transfer function of the filter has been developed. Furthermore, numerical analyses illustrate the effect of the loop phase, Q value and the injection ratio on the output results. The experiments validate the conclusions obtained in the theoretical analyses. Show more

Keywords: Magnetron, self-injection, qusai locking, noise reduction, high Q filter

DOI: 10.3233/JAE-150172

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. 1, pp. 71-81, 2016

Authors: Park, Eui-Jong | Suzuki, Kenji | Kim, Yong-Jae

Article Type: Research Article

Abstract: Along with the increased interest in high-load transport system, the linear motor has evolved from the conventional single-sided model to a double-sided model with armatures on both sides of the mover. However, the linear motor generally has armatures installed on the full length of the transport path, resulting in the increase in material costs and manufacturing time and thus limiting the application of this double-sided linear motor to long-distance transport systems. As a means to solve this problem, in this study, we propose a stationary discontinuous armature system and solve its problem which increasing the cogging force by ends between …armatures. Show more

Keywords: Double-sided PMLSM, discontinuous armature, armature offset, end cogging force, ripple, winding method

DOI: 10.3233/JAE-150152

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 637-645, 2016

Authors: Zygiridis, Theodoros T. | Kantartzis, Nikolaos V. | Tsiboukis, Theodoros D.

Article Type: Research Article

Abstract: The subject of this paper pertains to the construction of finite-difference expressions with minimized, as well as controllable discretization errors, suitable for 3D FDTD simulations in large-scale setups. The proposed spatial approximations are designed to mimic the behavior of the exact operators, when applied to plane-wave trial functions. To eliminate undesirable directional dependencies, the expansion of proper error formulae in terms of spherical harmonic functions is performed, which facilitates accuracy improvement and produces optimized operator coefficients in closed-form expressions. The combination of the new operators with low- as well as high-order time integrators yields efficient space-time discrete models, whose reliability …renders them desirable substitutes for other traditional solutions. Show more

Keywords: Finite-difference time-domain (FDTD) method, numerical dispersion, optimized algorithms, spherical harmonics

DOI: 10.3233/JAE-2010

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 51, no. s1, pp. S57-S66, 2016

Authors: Zheng, Shijie | Tong, Liyong | Luo, Quantian

Article Type: Research Article

Abstract: The present paper derives a 3-D finite element formulation and an iterative algorithm for multiphysics analysis of coupled anomalous photovoltaic, photo-thermal and pyroelectric effects in PbLaZrTi (PLZT) ceramics. The distinction in the computation aspects of electrical potential, electrical field strength and electrical charge for 0-1 and 0-3 polarized PLZT wafers are discussed thoroughly. The element performance is improved by using an assumed natural strain approach and an enhanced assumed strain method. The transverse displacements of a bimorph 0-1 polarized PLZT actuator were predicted using the present finite element formulation and then verified with the existing analytical solution and experimental results. …The static analysis of a cantilevered beam bonded with a 0-1 or 0-3 polarized PLZT actuators was also presented and compared with the theoretical solutions. The numerical simulations demonstrate that the present formulations and algorithm possess superior performance. Show more

Keywords: Finite element, 0-3 polarized PLZT, multiphysics analysis, solid-shell element, iterative algorithm

DOI: 10.3233/JAE-150058

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 513-530, 2015

Authors: He, Wei | He, Zhonghua

Article Type: Research Article

Abstract: A combination of passive shimming procedures is employed in the design of a unilateral Nuclear Magnetic Resonance magnet. The first shimming procedure used movable permanent magnets to correct the inhomogeneity of the B0 field to a relatively low level. In the second shimming procedure, the small iron pieces were used as shimming units, and their sizes and locations were predicted by using an integer programming method. Finally, the distribution of the shimming pieces was optimized and a special mathematic model was established. This hybrid technique provides a computational algorithm for optimizing the B0 homogeneity and for minimizing the number of …iron shimming pieces. A prototype unilateral NMR magnet has been built with this method. The B0 field measurement results were compared before and after the shimming. Employing this hybrid shimming method improved the uniformity of the B0 field from 4200 ppm to 796 ppm with only one iteration. Show more

Keywords: Passive shimming method, integer programming, unilateral nuclear magnetic resonance (UNMR)

DOI: 10.3233/JAE-150092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 4, pp. 597-606, 2015

Authors: Zhang, Yang | Lin, Heyun | Fang, Shuhua | Huang, Yunkai

Article Type: Research Article

Abstract: Permanent magnet vernier machine (PMVM) based on flux modulation principle has attracted increasing attention in low-speed direct-drive applications due to its high torque capability. A dual-stator PMVM topology with sandwiched spoke-array PM rotor is presented to produce higher air-gap flux density and larger torque in this paper, and the space utilization and the energy conversion efficiency are improved significantly. Two representative dual-stator PMVMs (DS-PMVMs) are designed with this topology, the pole/slot combinations and gear ratios of which are 18 slots/30 poles and 18 slots/28 poles, 5 and 3.5, respectively. In order to reveal the advantages of the proposed topology and …assess the torque characteristics of the proposed machines with different pole/slot combinations, the electromagnetic characteristics of these two machines are quantitatively compared and analyzed by using finite element method (FEM). The results demonstrate that the 18 slots/28 poles DS-PMVM can offer higher output torque, lower torque ripples, lower cogging torque and higher power factor owing to its optimal pole/slot combination. In addition, the unbalanced magnetic pulls (UMPs) of the two machines are also investigated, and the UMP of the 18 slots/30 poles DS-PMVM is smaller than that of its counterpart due to its symmetrical winding. Show more

Keywords: Direct-drive, dual stator, flux modulation, permanent magnet machine, vernier machine

DOI: 10.3233/JAE-150148

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 4, pp. 617-626, 2016

Authors: Mahmoud, Imed | Rehaoulia, Habib

Article Type: Research Article

Abstract: The present paper deals with design, modelling and characteristics of a biomedical system. The involved biomedical system is a syringe pump generally used for continuous drug infusion. The syringe pump consists of a linear switched reluctance motor (LSRM) coupled to a syringe plunger. In order to determine the axial force to control the syringe plunger, it was necessary to begin by evaluating the thrust force. For that purpose, an analytical approach is developed to evaluate the different forces and pressures involved. In addition, an experimental bench was conceived to determine the thrust force and validate the analytical model of the …syringe. Consequent results constituted the key element for designing and modelling the LSRM with the help of finite element methods (FEM). The final step is reserved to predict the dynamic performances of all the biomedical system with and without saturation. Show more

Keywords: Linear switched reluctance motor, syringe pump, modeling, finite-element methods and dynamic performances

DOI: 10.3233/JAE-150085

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 127-143, 2016

Authors: Boumaiza, Mostefa | Labed, Djamel

Article Type: Research Article

Abstract: In this work we study the coupling of a lightning wave with an overhead power distribution lines. The study is led directly in the time domain with hold in account of the effect of a finite conductivity of the soil. By the classic method poses a problem of digital heaviness linked to the spatial discretization and taking into account the electrical conditions at the ends of nodes and connections. The formalism that we propose overcomes the spatial discretization taking into account the electromagnetic aggression along each conductor and the electrical conditions at the ends allowing us to deduce the currents …and voltages induced in every node of the line directly. After discretization by the method so-called FDTD (Finite Difference Time Domain) of the lines equations excited by a lightning wave and the application in every node of the network of the Kirchhoff's laws in current and voltage, we deduct a equations system linear or no, of which the resolution permits us to deduct the induced electric quantities in every node of the network. In this study we propose a concept for the coupling analysis of a lightning wave with an overhead line without use of the least FFT. In order to confirm our theoretical work, we present a set of applications that allows validating this study. Show more

Keywords: Power distribution lines, lightning, electromagnetic field, ground transient resistance, induced voltage

DOI: 10.3233/JAE-140144

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 4, pp. 1093-1106, 2015