scholarly journals Expression for hysteresis loss of immobilized magnetic nanoparticles in a wide range of particle parameters and excitation conditions: Parameter optimization for hyperthermia application

AIP Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 125123
Author(s):  
Keiji Enpuku ◽  
Takashi Yoshida
2021 ◽  
Author(s):  
Mohamed Hamdalla ◽  
Benjamin Bissen ◽  
James D. Hunter ◽  
Liu Yuanzhuo ◽  
Victor Khilkevich ◽  
...  

<p>In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to the incident excitation properties such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions, the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems. </p>


2021 ◽  
Author(s):  
Mohamed Hamdalla ◽  
Benjamin Bissen ◽  
James D. Hunter ◽  
Liu Yuanzhuo ◽  
Victor Khilkevich ◽  
...  

<p>In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to the incident excitation properties such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions, the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems. </p>


2021 ◽  
Author(s):  
Leila Zahedi ◽  
Farid Ghareh Mohammadi ◽  
M. Hadi Amini

Machine learning techniques lend themselves as promising decision-making and analytic tools in a wide range of applications. Different ML algorithms have various hyper-parameters. In order to tailor an ML model towards a specific application, a large number of hyper-parameters should be tuned. Tuning the hyper-parameters directly affects the performance (accuracy and run-time). However, for large-scale search spaces, efficiently exploring the ample number of combinations of hyper-parameters is computationally challenging. Existing automated hyper-parameter tuning techniques suffer from high time complexity. In this paper, we propose HyP-ABC, an automatic innovative hybrid hyper-parameter optimization algorithm using the modified artificial bee colony approach, to measure the classification accuracy of three ML algorithms, namely random forest, extreme gradient boosting, and support vector machine. Compared to the state-of-the-art techniques, HyP-ABC is more efficient and has a limited number of parameters to be tuned, making it worthwhile for real-world hyper-parameter optimization problems. We further compare our proposed HyP-ABC algorithm with state-of-the-art techniques. In order to ensure the robustness of the proposed method, the algorithm takes a wide range of feasible hyper-parameter values, and is tested using a real-world educational dataset.


Author(s):  
En Rong Wang ◽  
Xiao Qing Ma ◽  
S Rakhela ◽  
C Y Su

A generalized model is proposed to characterize the biviscous hysteretic force characteristics of a magnetorheological (MR) fluid damper using symmetric and asymmetric sigmoid functions on the basis of a fundamental force generation mechanism, observed qualitative trends and measured data under a wide range of control and excitation conditions. Extensive laboratory measurements were performed to characterize the hysteretic force properties of an MR damper under a wide range of magnitudes of control current and excitation conditions (frequency and stroke). The global model is realized upon formulation and integration of component functions describing the preyield hysteresis, saturated hysteresis loop, linear rise and current-induced rise. The validity of the proposed model is demonstrated by comparing the simulation results with measured data in terms of hysteretic forcedisplacement and force-velocity characteristics under a wide range of test conditions. The results revealed reasonably good agreement between the measured data and model results, irrespective of the test conditions considered. The results of the study suggest that the proposed model could be effectively applied for characterizing the damper hysteresis and for development of an optimal controller for implementation in vehicular suspension applications.


A framework to perform video examination is proposed utilizing a powerfully tuned convolutional arrange. Recordings are gotten from distributed storage, preprocessed, and a model for supporting order is created on these video streams utilizing cloud-based framework. A key spotlight in this paper is on tuning hyper-parameters related with the profound learning calculation used to build the model. We further propose a programmed video object order pipeline to approve the framework. The scientific model used to help hyper-parameter tuning improves execution of the proposed pipeline, and results of different parameters on framework's presentation is analyzed. Along these lines, the parameters that contribute toward the most ideal presentation are chosen for the video object order pipeline. Our examination based approval uncovers an exactness and accuracy of 97% and 96%, separately. The framework demonstrated to be adaptable, strong, and adjustable for a wide range of utilizations.


2021 ◽  
Vol 1 (1) ◽  
pp. 32-47
Author(s):  
Anuj Kumar ◽  
Ankur Sood ◽  
Sung Soo Han

Biopolymers have attracted considerable attention in various biomedical applications. Among them, cellulose as sustainable and renewable biomass has shown potential efficacy. With the advancement in nanotechnology, a wide range of nanostructured materials have surfaced with the potential to offer substantial biomedical applications. . The progress of cellulose at the nanoscale regime (nanocelluloses) with diverse forms like cellulose nanocrystals, nanofibres and bacterial nanocellulose) has imparted remarkable properties like high aspect-ratio and high mechanical strength, and biocompatibility. The amalgamation of nanocellulose together with magnetic nanoparticles (MNC) could be explored for a synergistic effect. In this review, a brief introduction of nano cellulose , magnetic nanoparticles and the synergistic effect of MNC is described. Further, the review sheds light on the recent studies based on MNCs with their potential in the biomedical area. Finally, the review is concluded by citing the remarkable value of MNC with their futuristic applications in other fields like friction layers for triboelectric nanogenerator (TENG), energy production, hydrogen splitting, and wearable electronics.


1987 ◽  
Vol 31 ◽  
pp. 449-454
Author(s):  
James R. Bogert

One of the strongest analytical qualities of energy-dispersive x-ray fluorescence (EDXRF) is the wide range of analyte elements that can be detected and analyzed. Historically, the technique has covered all the elements from sodium (Z=11) and above. A useful measure of specific spectrometer performance is analyte sensitivity. X-ray spectrometric sensitivity is usually expressed in terms of minimum detectable amount of analyte or rate of change of analyte line intensity with change in amount of analyte. Many factors affect analyte sensitivity in EDXRF. These include excitation conditions, specimen conditions, system geometry, atmosphere, detector and readout conditions, and of course the specific analyte line. Typically, EDXRF sensitivity is very good, and low ppm concentrations of analytes are routinely analyzed–until one encounters the light elements.


1978 ◽  
Vol 22 ◽  
pp. 433-451
Author(s):  
Wolfhard Wegscheider ◽  
Bruce B. Jablonski ◽  
Donald E. Leyden

The determination of optimal excitation conditions for energy dispersive x-ray fluorescence is particularly critical for multielement analysis covering a wide range (viz. 10 or 20 keV) of the spectrum. Functions that quantitatively describe the spectral quality are used as objective functions in pattern search algorithms. It is shown that the filters can be arranged in a definite order, at least with respect to the energy of the K-absorption edge of the tube and can therefore be employed as a dimension in the optimization process. Of the algorithms that were compared, the Nelder-Mead and Routh-Swartz-Denton versions of the sequential simplex search gave the best results if the excitation voltage and the current could be controlled in small increments. If the optimization includes dimensions with a few discrete stages (e.g. filters) the fixed size simplex proved to be of greatest value. The functions can be weighted to reflect special interest in one or more elements. Conditions for increasing the counting time and terminating the search are discussed.


2016 ◽  
Vol 66 (4) ◽  
pp. 291 ◽  
Author(s):  
D. Mukherji

<p>Core-shell type magnetic nanoparticles are finding attractive applications in biomedicine, from diagnostic to cancer therapy. Both for targeted drug delivery and hyperthermia, as well as a contrast agent used for external biomedical imaging systems, small (&lt; 20 nm) superparamagnetic nanoparticles are desired. Some iron oxide nanoparticle formulations are already approved for human administration as contrast agent for magnetic resonance imaging. However, search continues for nanoparticles with higher saturation magnetisation. Metallic, bi-metallic and intermetallic magnetic nanoparticles are finding attention. Biocompatibility and optimal clearance are important criteria for the medical applications and therefore core-shell type particles are favored, where a biocompatible shell (e.g. polymer, Silica) can prevent inadvertent host reaction with the magnetic core. A recently developed novel synthesis method (electrochemical selective phase dissolution - ESPD), which can produce core-shell magnetic nanoparticles, is reviewed in this paper. ESPD, as the name suggests, uses electro-chemical separation of a phase from metallic alloys to synthesize nanoparticles. It is a versatile method and can be adopted to produce a wide range of nanostructures in addition to the core-shell magnetic nanoparticles.</p>


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