bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurocompensatory Effects of the Default Network in Older Adults
Authors: Duda Bryant M. , Sweet Lawrence , Hallowell Emily S. , Owens Max
Published: December 2018

The hemispheric asymmetry reduction in older adults (HAROLD) is a neurocompensatory process that has been observed across several cognitive functions but has not yet been examined in relation to task-induced relative deactivations of the default mode network. The present study investigated the presence of HAROLD effects specific to neural activations and deactivations using a functional magnetic resonance imaging (fMRI) n-back paradigm. It was hypothesized that HAROLD effects would be identified in relative activations and deactivations during the paradigm, and that they would be associated with better 2-back performance. Forty-five older adults (M age = 63.8; range = 53–83) were administered a verbal n-back paradigm during fMRI. For each participant, the volume of brain response was summarized by left and right frontal regions of interest, and laterality indices (LI; i.e., left/right) were calculated to assess HAROLD effects. Group level results indicated that age was significantly and negatively correlated with LI (i.e., reduced left lateralization) for deactivations, but positively correlated with LI (i.e., increased left lateralization) for activations. The relationship between age and LI for deactivation was significantly moderated by performance level, revealing a stronger relationship between age and LI at higher levels of 2-back performance. Findings suggest that older adults may employ neurocompensatory processes specific to deactivations, and task-independent processes may be particularly sensitive to age-related neurocompensation.
Physiological Amputation of Limb (Limb Gangrene) after Tourniquet Application for 12 days following Snake Bite
Authors: Yadav Ashok Kumar , Bhandari R. , Agrahari A.K. , Gupta R. , Shah M.K.
Published: December 2018

Background: Application of tourniquet and herbs has been practiced since a long time in patients with different reptiles’ and arthropods’ bite at rural areas of the country, despite various cases of cellulitis and gangrene.

Objective: To report a case of limb gangrene following tourniquet and herb application for snake bite.

Case: A 20-years old farmer, who was bitten by a snake, presented to the Emergency department with complaints of blackish discoloration of his left forearm and hand. After clinical evaluation and investigations, patient underwent surgical intervention.

Twelve days following snake bite, patient felt pain, noticed bleeding from bite site, swelling over his left hand, palpitation, shortness of breath and inability to speak. For which, he sought help from a traditional healer who applied a tourniquet over his left elbow and some herbs over the bite site. He noticed blackening of his fingers, which rapidly progressed to involve his left hand and forearm up to the site of tourniquet. He underwent surgery for the gangrenous limb.

Conclusion: Development of gangrene following tourniquet is an unusual finding in modern day medicine. This case report shows the danger related to tourniquet application and need for measures to prevent such incidents in future.
The hydraulics of constitutional claims: Multiplicity of actors in constitutional interpretation
Authors: Psygkas Athanasios
Published: December 2018

Who makes constitutional claims? This article argues that on both sides of the Atlantic a multiplicity of constitutional actors outside the courts participate in the elaboration of constitutional principles. I map out these constitutional actors by using as a case study the legal recognition of same-sex marriage in the United States, Spain, the United Kingdom, and Ireland. In all four country cases, there are common functional demands for democratic involvement in shaping constitutional meaning. Even though these demands may take various institutional and procedural forms owing to diverse political, institutional, and cultural contexts, I argue that the same overarching hydraulics effect is at play across jurisdictions. When social movements are shut out of one forum, they channel their constitutional claims through different institutional avenues. The four systems represent distinctive models of formal recognition of same-sex marriage, with different actors taking the lead and appearing to have the final say on this contested issue. However, I explain that in all four cases we can detect the voices of multiple actors, including, notably, the people themselves, in a process of legal contestation around the interpretation of fundamental constitutional principles. These voices can take different forms, and the article proposes institutional, historical, political, and cultural factors that may account for this. Thus, the article tells a story of legal development arising from inclusive interpretive communities in the context of a democratic constitutional theory. This framework facilitates dynamic constitutional interpretation that reflects evolving political and social demands instead of top-down delivery of constitutional meaning.
Potencijal entomopatogenih gljiva Metarhizium spp. u suzbijanju štetnih kukaca
Authors: Farić Nikolina , Sarajlić Ankica , Vrandečić Karolina , Majić Ivana
Published: December 2018

Radi otpornosti kukaca prema pojedinim kemijskim pesticidima, i sa svrhom proizvodnje hrane bez ostataka pesticida biološka zaštita biljaka od štetnih kukaca sve više je od značaja. Biološke metode se zasnivaju na primjeni prirodnih sredstava kao što su patogeni, paraziti i grabežljivci štetnih kukaca. Cilj ovog rada je prikazati prednosti i nedostatke pri upotrebi mikoinsekticida na bazi Metarhizium spp., uzimajući u obzir biologiju ovih gljiva, njihovu interakaciju s biljkom, okolišem, drugim organizmima i agrokemikalijama, te dostupnost mikoinsekticida na tržištu. Opisani su uspješni primjeri primjene ovih entomopatogenih gljiva u suzbijanju žičnjaka (Elateridae) i maslinove muhe (Bactrocera oleae), običnog crvenog pauka (Tetranychus urticae) i kruškine buhe (Cacopsylla pyri). Učinkovitost Metarhizium spp. u suzbijanju nekih vrsta kukaca je usporediva s metodom primjene kemijskih insekticida. Osim kao biopesticid, smatraju se i biostimulatorima, odnosno biofertilizatorima jer su endofiti. Dostupnost, visoka cijena mikoinsekticida te mali broj istraživanja u polju razlozi su slabe primjene u praksi.
Medical Plants and Nutraceuticals for Amyloid-β Fibrillation Inhibition
Authors: Witter Steffi , Witter Raiker , Vilu Raivo , Samoson Ago
Published: December 2018

Plaque formation due to amyloid-β oligomerization and fibrillation is a key issue for its deposition in the brains of dementia and Alzheimer’s disease patients. Related drugs preventing this peptide fibril accumulation bear the potential of considerable medical and social value. In this study, we performed in vitro fibrillation inhibition tests with eight different medical plant extracts and nutraceuticals using fluorescence spectroscopy. Successful inhibition of the following plant extracts and nutraceuticals were obtained: Withania somnifera, Centella asiatica, Bacopa monnieri, and Convolvulus pluricaulis, providing new drug candidates for the prevention and treatment of Alzheimer’s disease.
Lipopolysaccharide Induced Opening of the Blood Brain Barrier on Aging 5XFAD Mouse Model
Authors: Barton Shawn M. , Janve Vaibhav A. , McClure Richard , Anderson Adam , Matsubara Joanne A. , Gore John C. , Pham Wellington
Published: December 2018

The development of neurotherapeutics for many neurodegenerative diseases has largely been hindered by limited pharmacologic penetration across the blood-brain barrier (BBB). Previous attempts to target and clear amyloid-β (Aβ) plaques, a key mediator of neurodegenerative changes in Alzheimer’s disease (AD), have had limited clinical success due to low bioavailability in the brain because of the BBB. Here, we test the effects of inducing an inflammatory response to disrupt the BBB in the 5XFAD transgenic mouse model of AD. Lipopolysaccharide (LPS), a bacterial endotoxin recognized by the innate immune system, was injected at varying doses. 24 hours later, mice were injected with either thioflavin S, a fluorescent Aβ-binding small molecule or 30 nm superparamagnetic iron oxide (SPIO) nanoparticles, both of which are unable to penetrate the BBB under normal physiologic conditions. Our results showed that when pretreated with 3.0 mg/kg LPS, thioflavin S can be found in the brain bound to Aβ plaques in aged 5XFAD transgenic mice. Following the same LPS pretreatment, SPIO nanoparticles could also be found in the brain. However, when done on wild type or young 5XFAD mice, limited SPIO was detected. Our results suggest that the BBB in aged 5XFAD mouse model is susceptible to increased permeability mediated by LPS, allowing for improved delivery of the small molecule thioflavin S to target Aβ plaques and SPIO nanoparticles, which are significantly larger than antibodies used in clinical trials for immunotherapy of AD. Although this approach demonstrated efficacy for improved delivery to the brain, LPS treatment resulted in significant weight loss even at low doses, resulting from the induced inflammatory response. These findings suggest inducing inflammation can improve delivery of small and large materials to the brain for improved therapeutic or diagnostic efficacy. However, this approach must be balanced with the risks of systemic inflammation.
Analysis of dynamic response of plasma polymer film-coated quartz crystal resonator sensor
Authors: Takahashi Kazuhiko , Iwamuro Yusuke , Sugimoto Iwao
Published: December 2018

This paper proposes a mathematical model of a mass-sensitive chemical sensor with a plasma polymer film (PPF)-coated quartz crystal resonator (QCR) that can be used to process signals from gas sensing systems that are operated under ambient conditions. To approximate the responses of the PPF-coated QCR sensor to the sample gas, a mathematical model based on the diffusion equation (assuming the one-dimensional Fickian diffusion of the sample gas molecules into the sensor film) is investigated based on the assumption that the sorption/desorption phenomena occur in the vicinity of the PPF surface. Computational experiments show the feasibility of the proposed mathematical model for estimating the response of the PPF-coated QCR sensor.
Large and symmetric deflection of Acryl plate-CFRP plate laminate actuator
Authors: Lin Wenyi , Sasaki Minoru , Tamagawa Hirohisa
Published: December 2018

Unlike well-investigated polymer-based soft actuators such as gel, Ionic Polymer-Metal Composite, conducting polymer, a CFRP-based polymeric laminate possesses quite distinguished properties. It was previously reported that a CFRP-PVC laminate exhibited two-way deflection in accordance with environmental temperature, but it could not exhibit symmetric deflection because of its asymmetric structure. It must broaden the potential usefulness of the CFRP-based polymeric laminate as a soft actuator by achieving its symmetric deflection. In this study, we attempted to fabricate a new CFRP-based polymeric laminate which could exhibit symmetric deflection by electrical laminate temperature control. Despite such a successful outcome, still there was a room to improve the performance of the new CFRP-based polymeric laminate especially about the degree of its deflection. Its deflection was not so large for the actuator use. Hence, we further attempted to fabricate another CFRP-based polymeric laminate which could exhibit large and symmetric deflection under electrical control of laminate temperature. In fact, this another CFRP-based laminate exhibited symmetric deflection in accordance with temperature and the deflection was indeed enhanced.
Analytical modelling for edge effects and impedance characteristics of the transverse eddy current displacement sensors with rectangular coils
Authors: Lv Chunfeng , Liu Weiwen , Jiang Yingying , Zhao Hui
Published: December 2018

Analytical method for eddy current evaluation is an attractive field of learning the concept of electromagnetic phenomena. This paper proposes an analytical approach to a transverse eddy current displacement sensor with a rectangular testing coil. Solving domain in the Cartesian coordinate system is limited to finite extents through imposing artificial boundaries at x and y axis, and solutions to the electromagnetic field are expressed as double series. Complete closed-form expressions based on second order vector potential for the electromagnetic field in each region can be obtained from the continuity conditions at the interfaces by mode matching. Closed-form expressions of the eddy current density as well as coil impedance related to the transverse displacement can thus be derived, and the calculated results show good agreement with the experimental results.
Modeling and comparison of the Halbach array with different segments per pole
Authors: Zhou Yunfei , Liu Guangdou , Zhou Rougang , Huo Ligang , Ming Wuyi
Published: December 2018

In this paper the Halbach array with different segments per pole are modeled and compared. The unified harmonic model for the magnetic flux density distribution of the Halbach array with different segments per pole is derived by using Fourier series and magnetic scalar potential. The coil power dissipation and higher harmonics are compared with the Halbach arrays, respectively. The dimension parameter of magnet array is optimized on the basis of minimum coil power dissipation by taking the magnetically levitated planar motor with moving magnets for example. The genetic algorithm is used to minimize the higher harmonics in z-component of the magnetic flux density distribution. Then the dimension parameters of magnet arrays are obtained, according to that the arrays are compared on the ratio between the higher harmonics and analytical model of z-component of the magnetic flux density distribution and the peak value of z- and x-component of the magnetic flux density distribution. The Halbach array with 3 segments per pole is chosen on the basis of the above comparison.
A hybrid model of Prandtl-Ishlinskii operator and neural network for hysteresis compensation in piezoelectric actuators
Authors: Chen Yuansheng , Qiu Jinhao , Sun Hongjun
Published: December 2018

A hybrid model is proposed with the Prandtl-Ishlinskii operator and feedforward neural network. The hybrid model consists of three layers, where play operator is the transfer function of first layer. The training algorithm for model identification is derived from the backpropagation algorithm. With the measured data of piezoelectric actuator, a simulation is performed and shows that the hybrid model can precisely describe the asymmetric hysteresis loops. Incorporating the hybrid model into a feedforward controller, experiments indicate that the hybrid model exhibits a good performance for real-time control and the maximal tracking error is reduced by 76.75% with feedforawrd and PID controller.
Generator with levitated magnet for vibration energy harvesting
Authors: Olaru R. , Gherca R.
Published: December 2018

In this paper is presented an extensive theoretical study and some experimental results regarding an electromagnetic generator based on levitated magnet, designated to harvest energy from ambient vibrations. Generator optimization for achieving the maximum values of transmissibility and electrical power was performed by considering a resonance frequency different from the natural frequency that is usually used in literature. The step response of the system, described analytically, is useful in the analysis of generators subject to sudden variations of the random vibration amplitude. The obtained experimental results indicate the possibilities of optimization and increase of the device power depending on the frequency and amplitude of external vibrations. The generator with levitated magnet studied in this paper, provided a maximum power of 27 mW when working as a quasi-linear oscillator and of 64 mW, respectively, when working as a non-linear oscillator.
Active electromagnetic suspension system design using hybrid neural-swarm optimization
Authors: Adly A.A. , Abd-El-Hafiz S.K.
Published: December 2018

Recently, utilization of electromagnetic suspension systems has been on the rise as a result of novel space and automotive-related industrial applications. This paper presents an efficient iterative hybrid neural-swarm optimization methodology for electromagnetic suspension system design involving nonlinear magnetic media. Within this approach, 2D field computations are carried out using the integral equation approach in an automated mechanism through continuous Hopfield neural network (HNN) implementation. Optimal dimensions of the system are identified through the minimization of an error function of some target performance using the particle swarm optimization (PSO) evolutionary approach. Details of the approach and sample design examples are given in the paper.
Reliability-based design optimization using local sensitivity with application to magnetic nano switch
Authors: Pham-Quang Phuong , Delinchant Benoit , Coulomb Jean-Louis
Published: December 2018

This paper presents a method and a tool for solving the reliability-based design optimization (RBDO). The RBDO aims to minimize a cost function by changing the value of design parameters while ensuring a level of reliability. Uncertainties propagation is a key concept in reliable studies and it can be associated with a sensitivity analysis in order to sort parameter influences. Global and local sensitivities are compared in this study in order to keep a reasonable cost versus accuracy ratio. A software tool has been also developed to automate reliable studies. It is applied to the reliable optimization of a magnetic nano switch with SQP algorithm using Jacobian calculated by composition of automatic and symbolic differentiation.
Improved processing and performance of GDI injector based on metal injection molding technology
Authors: Cheng Qiang , Zhang Zhendong , Guo Hui , Xie Nailiu
Published: December 2018

A new near-net-shape technology (MIM Technology) has been first introduced to GDI injector processing expected to solve the problems of inefficiency, low machining accuracy, low material utilization rate and unstable performance that exist in traditional processes. In order to improve the comprehensive performance of GDI injector Fe-based Nano-crystalline, soft magnetic alloy material has been used, and some structures of the magnetic circuit parts have been optimized. The excellent machinability, physicochemical properties, materials applicable of the MIM technology has been analyzed by tracking test. The comprehensive performances of different GDI injector samples have been analyzed by simulation analysis and experimental validation. As a result, the samples which were processed by the MIM technology reduce the skin effect and eddy current loss by 9.8%, accelerate the starting current rise rate by 2.5% and shorten the dynamic response time by 14.2%. The dynamic injection quantity increases by about 2.5%, and the linear range of dynamic fuel injection quantity is expanded about 9.6%.
Electro-elastic fields around an elliptical hole in an electrostrictive plate: Isotropic and uncoupled cases
Authors: Meng Licheng , Gao Cun-Fa
Published: December 2018

This work studies on the classical electro-mechanical problem of an electrostrictive plate with an elliptical hole. In the present work, the isotropic case for the electrostrictive plate is considered based on the small strain assumption. The solutions are then provided by the complex variable method for an infinite plate with an elliptic hole or a crack. Moreover, FEM analyses where a 3D electrostrictive element is defined in ABAQUS user subroutine UEL are presented for a finite plate. Numerical results are given to discuss the effects of plate geometries, applied electric fields, material properties, the electric body force and Maxwell stress tensor on the stress fields around the elliptical hole. It is found that the traditional uncoupled treatment may cause an unpredictable inaccuracy and a coupled analysis is needed in general.
Broadband complex permittivity determination using a two-port U-shaped coplanar waveguide with artificial neutral network algorithm
Authors: Yang Yang , Zhu Huacheng , Fan Lei , Luo Yan , Zhang Fuhao , Huang Kama
Published: December 2018

A two-port U-shaped Coplanar Waveguide (U-CPW) used for broadband complex permittivity measurement of high loss solutions is presented. Compared with the one-port measurement device, this two-port U-CPW coupled with artificial neural networks algorithm has the ability of reducing the multiple-solutions. Also, the measured T/R (transmission/reflection) coefficients were used instead of simulated reflection coefficients for training the neural networks that enhanced the accuracy of measurement results. Two real-valued neural networks associated with the U-CPW are used to reconstruct the two parts of the complex permittivity separately from the measured T/R coefficients. First, a large number of measured T/R coefficients of broadband frequency points of ethanol-water mixtures along with their theoretical complex permittivity are used to train two separate neural networks. Second, the trained networks are employed to reconstruct the complex permittivity of other solutions using the measured T/R coefficients. Compared with the results of Cole-Cole equation, the reconstructed results of methanol-water mixtures and ethanol-methanol mixtures at different volume fractions have been obtained with sufficient degree of accuracy in the frequency range 1–3 GHz at 20°C. For predicted values using the developed artificial neural network (ANN) architecture and those obtained from literature, the average relative errors of real and imaginary parts of complex permittivity are 2.27% and 2.12%, respectively.
Design of piezoelectric transformer-based DC/DC converter to improve power by using heat transfer equipment
Authors: Su Y.H. , Liu Y.P. , Vasic D. , Costa F. , Wu W.J. , Lee C.K.
Published: December 2018

In this paper, we propose a new design of a piezoelectric transformer (PT) for low-profile DC/DC converter applications, which increases the output power by using heat transfer equipment. We examined several parameters, which allow us to produce a piezoelectric transformer with optimal efficiency. Instead of looking at the typically optimal loading condition of the PT, we consider the influence of the temperature rise on losses. When the vibration velocity is too large, the piezoelectric transformer generates heat unstably until it cracks. By maintaining the vibration mode and limiting the heat produced by the PT, this design can enhance the power capacities of the PT and thus increase the output power of the DC/DC converter. A finite element analysis (FEA) approach with COMSOL Multiphysics was made to predict PT's working temperature. A theoretical-phenomenological model was also developed to explain the relationship between the equivalent losses resistances and the input voltage at different temperatures. It will be shown that the vibration velocity as well as the heat generation increases the losses. A large vibration velocity and generated heat may cause the temperature feedback loop to enter into an unstable state. We began by modeling a piezoelectric transformer in a DC/DC converter configuration in order to determine the design constraints and variables such as the maximum mechanical current, the temperature distribution, the PT geometrical configuration and the energy balance. In our design, the PT power capacity increases 3 times (i.e. from 4.54 W to 13.29 W) at specific temperature and the effects of the different cooling methods of the system were verified. The study comprises of a theoretical part and experimental proof-of-concept demonstration of the proposed design method.
Modelling and experiments of PLZT/PVDF hybrid drive method for non-contact shape adjustment
Authors: Yue H.H. , Jiang Jing , Long Y.F. , Song Y.J.
Published: December 2018

In order to improve the technical specifications of space reflectors, antennas and other payloads on Earth observation, space communication, deep space exploration and other fields of space applications, people urgently need to enhance the surface shape control accuracy of these large complex curvature flexible structures. Based on the photovoltaic effect and converse piezoelectric effect, this paper presents a non-contact shape-adjusting method which adopts a new space energy conversion: using the PLZT photovoltage, which is controlled by the ultraviolet, to activate the PVDF attached on the flexible structure surface, and adjust and control the structure's shape. This paper firstly built up the electric model of the PLZT/PVDF hybrid drive, derived the constitutive relation of light-electric-mechanical energy field conversion, and determined the key parameters in mathematical model by principle experiments. Then, taking a flexible cantilever beam as the control object, actuation equation of the PVDF bonded structure was built, and actuation properties and influence factors of the cantilever beam actuated by the PLZT/PVDF hybrid drive were simulated and analyzed. After that, the hybrid drive experiment system was built up, and deflecting effect of using ultraviolet illuminated PLZT to actuate PVDF bonded cantilever beam was tested, whose result verified the validity of theoretical modeling and simulation analysis. Lastly, characteristics of the hybrid drive method and conventional PVDF driving were compared, and space application direction of this method was pointed out.
Subwavelength negative index planar terahertz metamaterial arrays using spiral split ring resonators for near field sensing
Authors: Naeem Nadeem , Ismail Alyani , Alhawari Adam Reda Hassan , Mahdi Mohd Adzir
Published: December 2018

This study reports new shape of meta-material array structures having electric and magnetic resonances designed for terahertz (THz) frequency band. The proposed structures exhibit left handed meta-material propertiesin THz frequency band. The introduced meta-material split ring resonators in this paper are constructed using a single loop of conducting wire strip printed over a very thin low permittivity polyimide dielectric substrate. The effective parameters like permeability and negative index are extracted from the simulated complex scattering parameters using direct retrieval method. Unloaded Q-factor is calculated for proposed terahertz metamaterial resonators. The proposed arrays are tested by loading different dielectric samples in order to confirm the testing capability. Significant shift in the transmission is observed. The reported array structures are novel in terms of their left handed behavior in THz frequencies. High values of Q-factor reported here, are suitable for near field sensing applications.
Approach for a fast computation of induced magnetic field created by naval vessels
Authors: Zhou Guohua , Liu Shengdao , Xiao Changhan , Liu Daming
Published: December 2018

Integral equation method is widely used in magnetic field modeling of ships, but its nonsymmetric and dense coefficient matrix results in low computation efficiency and large memory, which limits its application in large scale problems. An approach for a fast computation of induced magnetic field created by ships was presented based on multiple layers fast multipole method and vector integral equation method. The numerical implementation of the proposed approach was described in detail. It is shown by an analytical sphere example and a simplified mock-up experiment that the proposed approach can reduce computation time and memory cost in induced magnetic field modeling of ferromagnetic objects.
Analysis of multi-direction low-frequency vibration energy harvester using diamagnetic levitation
Authors: Ye Zhitong , Duan Zhiyong , Su Liushuai , Takahata Kenichi , Su Yufeng
Published: December 2018

This paper presents theoretical analysis and verification of a micro vibration energy harvester based on magnetic levitation using diamagnetic structures. The analysis verifies that diamagnetic material experiences anti-magnetic force in magnetic field and that it can be used for stable magnetic levitation. This study proposes a novel design that is comprised of a lifting permanent magnet, an upper pyrolytic graphite sheet, a floating permanent magnet, and a lower pyrolytic graphite sheet, with copper spiral coils formed on the two pyrolytic graphite sheets. The gravity of the floating permanent magnet is balanced by the attractive force between the lifting and floating magnets. The diamagnetic force exerted on the levitated magnet by the two pyrolytic graphite sheets serves as a restoring force, forcing the floating permanent magnet return to the equilibrium position. Through finite element analysis, the maximum movable range of the floating magnet is defined to be 1.3 mm. Comparative analysis of the attractive magnetic force and the anti-magnetic force is performed to determine the key parameters of the structure. The characteristics of vertical and horizontal motion of the magnet are also studied in detail. The results validate the effectiveness of the proposed design for harvesting multi-dimensional, low-frequency vibration energy. The diamagnetic levitation mechanism without conventional mechanical suspensions eliminates loss of vibration energy and resultant thermal issues. The system is potentially promising, through further miniaturization, in providing sustainable power for micro-electro-mechanical systems.
Magnetic coupler design procedure for IPT system and its application to EVs' wireless charging
Authors: Hu Chao , Sun Yue , Lv Xiao , Wang Zhihui , Xiong Qingyu
Published: December 2018

Magnetic coupler is the most critical part to achieve high power transmitting capability in an inductive power transfer (IPT) system. This paper introduces a design procedure of magnetic coupler. Based on the design procedure, the main parameters that affect the output power and power loss of the magnetic coupler have been found. In order to stable the operating frequency, equations which calculate the receiver self-inductance and the magnetic coupler mutual inductance are developed and analyzed. Moreover, the parameters of Double-Layer-Double-D (DLDD) coil which is designed for electric vehicles' (EVs') wireless charging are derived according to the magnetic coupler design procedure. The experimental results show that the power transfer efficiency (PTE) of an IPT system with DLDD coil can be as high as 85.1% with a transmitting distance of 15 cm, while the output power is 10 kW.
Analysis and design of high-efficiency resonant inverters for domestic induction heating applications
Authors: Sarnago H. , Lucía O. , Mediano A. , Burdío J. M.
Published: December 2018

Nowadays, the induction heating market is continuously growing due to its benefits including precise output power control, reduced heating times, and cleanness. The domestic induction heating application, based on the same principle, includes some extra features such as the controlled temperature profiles or over-temperature detection for an outstanding cooking process. Because of the high power density and the reduced cooling capabilities, efficiency becomes critical in this application. This paper introduces some techniques to improve the efficiency of the induction heating power converters. The proposed converters are analyzed, including the main losses sources, proving that the proposed solution improves the overall efficiency while the component count and cost are keep to reasonable values.
Induction heating using a two-phase travelling wave setup
Authors: Frogner Kenneth , Cedell Tord , Andersson Mats
Published: December 2018

A laboratory implementation of a two-phase travelling wave induction heating setup is described. The focus is the development of a versatile power control system for multi-coil experiments and parameter studies. The drive system features high temporal accuracy, full real-time controllability, and integrated measurement technology, analyzed step wise. The performance was tested using a full pitch travelling wave inductor based on litz wire with a flux concentrator from a powder material. Thermographic images from the experiments are presented and the results are compared with simulations. The challenges related to multi-coil configurations are explained, many of which are difficult to predict from simulations.
Neural network based model for incorporating the thermal effect on the magnetic hysteresis of the 3F3 material
Authors: Nouicer Abdelmadjid
Published: December 2018

This paper presents a new approach for incorporating the thermal effect on the magnetic hysteresis of the 3F3 material. The proposed algorithm is based on the knowledge of the magnetic flux density spectrum for some temperatures. So, a feed-forward neural network is trained to learn the relation between the rank of harmonics, the temperature and the amplitude of each harmonic. To construct the hysteresis loop for a new value of the temperature, the neural network predicts the spectrum of the magnetic flux density B which is transformed back to the time domain.
Loss analysis of electromagnetic linear actuator
Authors: Dai Jianguo , Chang Siqin
Published: December 2018

This paper presents the research on loss analysis of the electromagnetic linear actuator (ELA) with the purpose of performance improvement of ELA applied to the engine electromagnetic driven valve train(EDVT). To define ELA's loss distribution and variation, quantitative analysis has been carried out against ELA's loss composition and variation at different engine conditions through simulation of three-dimensional (3D) finite element. Meanwhile, in order to verify reliability of simulation model, locked-mover test has been completed creatively. Then it analyzes the impact of flux density and excitation period on ELA's loss and thus some regular understandings are obtained. In the end, the result shows that the test data and simulating calculation agree well, and the error is less than 3.9%.
Concept for more correct magnetic power loss measurements considering path length dynamics
Authors: Pfützner Helmut , Shilyashki Georgi , Palkovits Martin , Galabov Viktor
Published: December 2018

In principle, single sheet testers (SSTs) or Epstein testers (ETs) determine iron losses p through the time integral over the field H and the time derivative of the induction B. Both quantities should be determined in equivalent ways, i.e. considering an identical quasi-homogeneously magnetized sample section. Partly, this condition is fulfilled by H-coil methods. However, the so far used very small coils do not meet the demand of equivalence. At least outside of Japan, most labs prefer apparatuses where H is assumed to be proportional to the magnetization current i. But exact proportionality does not exist due to the periphery – the yoke of SST and the corners of ET, respectively. Usually, the periphery is considered through a constant effective magnetic path length l_M based on the peak induction B_p . But in fact, l_M varies during the period, i.e. it is a function of B(t) and thus also of time. Our novel "PLC method" is characterized by path length consideration. We consider dynamics of length through a "path length function" Λ (B) which is determined for each grade of material in a calibration process by means of a large, rigid H-coil. Considering Λ [B(t)] by software, routine measurements on similar materials can be based on the "corrected" current i(t)/Λ (t). First results are presented for HGO SiFe investigated in an ET. Here, Λ proves to be above 1 for low B and below 1 for very high B. As a final target, application of the method for both ETs and SSTs should yield almost identical loss values that are close to "true" ones.
Surface field measurements in vector characterization of Si-Fe magnetic steel samples
Authors: Cardelli Ermanno , Faba Antonio , Tissi Francesco
Published: December 2018

In this work we discuss some procedures to increase the accuracy in the measurement of the magnetic field strength using Round Rotational Single Sheet Tester RRSST frames. The procedures are discussed jointly with the use of different magnetic field probes, such as flat coils and Hall sensors, and with a suitable shielding geometry. Experimental comparison between different methods and a discussion about the results is presented.
Deformation of a ferromagnetic plate in an oblique field considering saturation
Authors: Leiss-Holzinger Elisabeth
Published: December 2018

The magnetic field distribution in and around thin ferromagnetic structures has been explored. Extrapolation and mathematical air flux compensation were used to obtain magnetic quantities on the sample surface and inside the sample, minimizing systematic errors for flux-metric and Gauss-metric measurements. A magneto elastic model was applied describing large deformations of thin ferromagnetic structures in a static magnetic field. The model based on global balance equations obeys the conservation of energy and momentum. Exemplified by the deformation of a soft-magnetic elastic plate in a uniform transverse magnetic field, the numerical evaluation of the model was compared to experimental results. Field distribution and deformation of the plate in a stepwise increased external field showed good agreement from small magnetization up to saturation.
The dynamic behaviour of a micro liquid bridge of magnetic fluid in static and alternating magnetic fields
Authors: Sudo Seiichi , Takamatsu Hiroki , Yano Tetsuya , Takana Hidemasa , Nishiyama Hideya
Published: December 2018

Experimental study on the dynamic behaviour of magnetic fluid micro bridges under the effect of static and alternating magnetic fields was conducted using a high-speed video camera system. Two needle-shaped NdFeB permanent magnets were used to generate the static magnetic field, and Helmholtz coil was used to generate alternating field. Harmonic motion of magnetic fluid bridge was observed. It was found that the amplitude in the vibration of magnetic fluid bridge depends on the strength of alternating magnetic field at the constant frequency. Phenomena of filament thinning and breakup in a capillary bridge of magnetic fluid under the alternating magnetic fields were revealed.
Experiment of receiving ultrasonic wave by using adhesion and a contact type PVDF sensor
Authors: Tone Ryota , Tanaka Yoshikazu , Fujimoto Yukio
Published: December 2018

A nondestructive method that evaluates the distribution of plastic strain using an ultrasonic wave would be useful for estimating a structure's state prior to crack development. The authors have proposed an ultrasonic wave measurement method by combining an EMAT and PVDF, in which the couplant is not needed if a contact-type PVDF sensor is used.

This paper reports on the comparison and examination of adhesion-type and contact-type PVDF sensors combined with an EMAT for ultrasonic wave transmission.
Enhanced image processing and archiving capabilities of magneto-optical imaging for non-destructive evaluation
Authors: Genest Marc , Mandache Catalin
Published: December 2018

In its current state, the wide acceptance of the Magneto-Optical Imaging (MOI) technique is hindered due to noise, lack of recordable results, and impossibility of data post-processing. This paper presents some add-ons made to a commercial MOI system to ease the image interpretation, archiving and reporting of the results. In addition, a few image processing techniques are also employed in an attempt to perform automatic flaw detection. The recording capability of the MOI instrument output images was addressed by digitizing the video signal in video or image files. To help with the identification of the damage location and distance between images, a rotary quadrature encoder was mounted onto the MOI scan head. The use of the encoder allowed the identification of the inspection location with respect to a reference position, such as the beginning of the scan. Moreover, it allowed saving images at fixed intervals, which were then stitched into a single image, thus simplifying the post inspection analysis process. Both live and post-inspection image processing capabilities were made available. Implemented image processing included background subtraction, de-noising, contrast adjustment and morphological operation, among others. Contrast stretching transform and background subtractions were found to be among the most powerful techniques that could be used in simplifying the image interpretation.
The investigation on a thrust force 8,000 N class transverse flux linear motor
Authors: Hong Do-Kwan , Joo Daesuk , Woo Byung-Chul , Han Pil-Wan
Published: December 2018

The objective of the present study is to handle the optimum design of PMs excited TFLMs to transfer for high speed and heavy-load robots which transfer LCD glass panels to maximize thrust force and to minimize attraction force, thrust force ripple ratio, and attraction force ripple ratio. The predicted performance of the optimized TFLM is in accord with the 3-D FEM results. The static thrust force by test is performed to compare simulation results. The estimated error is within 4.1%, and the developed prototype is operated for 3 m/s by synchronous control driver to control both 4,000 N class TFLMs. Experimental validation is successfully performed to verify the design and analysis by optimum design.
A design method of a single-phase LSPM using ferrite magnet
Authors: Choi Myoung-Hyun , Kim Byung-Taek
Published: December 2018

This paper proposes a design method considering an irreversible demagnetization, the largest problem of the single-phase LSPM using ferrite on start-up. A parameter satisfying maximum output is extracted from the equivalent circuit in steady state, which is used to determine number of turns and shape. Here, back electromotive force and maximum output are selected as design variables for minimizing the effect of demagnetization and size, and the optimal design point is determined with consideration on the efficiency and maximum output of the single-phase motor.
Identification of impact load using transient statistical energy analysis method
Authors: Mao Boyong , Xie Shilin , Zhang Xinong
Published: December 2018

A new identification method for impact loads is proposed based on the transient statistical energy analysis theory. The load identification problems of structure subjected to single excitation are classified into three cases according to the completeness of load location information and subsystem response set. The input energy of impact load and the load location is firstly identified from the averaged vibration energy responses of subsystems according to energy balance equation for three cases. The load amplitude spectrum is thereafter derived under the assumption of constant value of itself from the identified input energy within each analytical frequency band. Finally, the time history of impact load is further determined for the given load time domain waveform using a developed fitting method. The experimental studies of impact load identification are conducted on a plate-shell assembled structural system. The results show that the location and input energy of impact load can be identified with fairly accuracy using the presented identification method. Besides, both the load spectrum and time history of impact load have good agreements with the measured ones.
Magnetic gear scaling analysis using magnetomechanical deflection analysis
Authors: Uppalapati Kiran , Bird Jonathan Z.
Published: December 2018

In this paper the mechanical deflection of steel bars, of different length, in a flux focusing magnetic gear is studied. The mechanical deflection is caused by the magnetic attraction between the steel bars and the inner and outer rotor magnets of the magnetic gear. An iterative magnetomechanical approach using commercial finite element analysis software has been adopted. Two different diameter magnetic gear models with different axial lengths have been modeled and the deflection has been calculated for each model. Experimental verification for one model is also shown. The paper shows that when operating with a small air-gap and long axial length the mechanical deflection can become significant.
Effect of power frequency on the stress state of disc actuator
Authors: Jankowski Piotr , Mindykowski Janusz , Woloszyn Miroslaw
Published: December 2018

This paper presents the concept of determining the optimum frequency of coil supply in inductive-dynamic drive. As a criterion to obtain the sought frequency, the smallest value of reduced stress in the disc was assumed while maintaining the desired dynamics. The disc stress is determined on the basis of solution of vibrating thin plate equation. Magnetic pressure acting on the disc is obtained from a hybrid circumferentially-field model (CI-FI).
Damping characteristics of a magnetic fluid tuned liquid column damper under static magnetic fields
Authors: Oyamada Toshiyuki , Masuda Hideaki , Ikari Kazuki , Sawada Tatsuo
Published: December 2018

Magnetic fluid tuned liquid column damper (MF-TLCD) is a new semiactive damper. This device can exhibit high damping effect by tuning its natural frequency to the excitation frequency. In this study, the vibration characteristics of a magnetic fluid under a static magnetic field were investigated by linear analysis and experiment with single-degree-of-freedom oscillation. Moreover, MF-TLCD was installed within a structure and oscillated in double-degrees-of-freedom. It was confirmed that MF-TLCD could achieve high performance compared with the conventional TLCD by controlling the magnetic field.
Effect of chamfered orifice inlet on magnetorheological fluid subjected to shock loading
Authors: Isnikurniawan Ahmad , Ohba Hiromichi , Kaneko Hiro , Yoshizawa Ryo , Sawada Tatsuo
Published: December 2018

This study is an investigation on the effect of a chamfered orifice inlet on magnetorheological (MR) fluid subjected to shock loading. Three different orifices (without chamfer, chamfered at 60°, and chamfered at 120° on the inlet area) are used. MR fluid is subjected to shock loading, and a magnetic field is generated on the orifice area. Experiments are conducted by measuring piston displacement and damping force. Piston velocity is calculated from the piston displacement data. The results indicate that a chamfered orifice inlet affects the piston stroke, piston velocity, and damping force. The characteristics of piston velocity between the orifice without chamfer and the chamfered orifices are different. The post-peak decrease in piston velocity in the chamfered orifices is more refined than that in the orifice without chamfer. However, the chamfered shape in the orifice inlet reduces the shock loading performance of MR fluid.
Study on a roller scanning type palpation sensor
Authors: Tanaka Mami , Tamura Makoto , Okuyama Takeshi
Published: December 2018

Palpation is a simple diagnosis method that doctors examine body and organs of patients by feeling with their hand. However, palpation is not objective because the palpation sensitivity depends on skill and experience of doctors. Therefore, an objective method for measuring tactile information is required. In this study, a palpation sensor system for detecting a lump is proposed and fabricated. Fundamental characteristics of the sensor are examined by using measuring objects made of polyurethane resin and aluminium rods as a lump. A peak waveform appears in the sensor output when the sensor is above the lump. In addition, the measuring objects using the silicone cylinder are made in place of aluminium rod. Also, the experiment is done, and the features of peaks are investigated. From the results, it is confirmed that the sensor is available to detect the lump.