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Journal articles on the topic 'External coil'
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1
Yazid, Izyan Iryani Mohd, Saiful Amri Mazlan, Takehito Kikuchi, and Hairi Zamzuri. "Experimental Investigation of Multiple Coils Magnetorheological Damper under Dynamic Loadings." Applied Mechanics and Materials 660 (October 2014): 863–67. http://dx.doi.org/10.4028/www.scientific.net/amm.660.863.
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This paper presents performance comparison of Magnetorheological (MR) damper with two different coil arrangements. Two coils at different location have been introduced that could enhance the activation areas in the MR damper. The experimental tests were conducted in three different conditions of coil; internal coils, external coils and the combination of coils. For each trial, the effect of the applied current and the condition of coils were analyzed and investigated. The results showed that the internal coil could produce higher damping force than the external coil, and the combination of internal and external coils could increase the damping force up to 125 N for the same experimental parameters.
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Rajput, Shailendra, Efim Lockshin, Aryeh Schochet, and Moshe Averbukh. "Reactance Regulation Using Coils with Perpendicular Magnetic Field in the Tubular Core design." Applied Sciences 10, no. 21 (2020): 7645. http://dx.doi.org/10.3390/app10217645.
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This article presents an efficient method for prosumer connection to the distribution line. The prosumers can be connected to the distribution line using specially designed controllable reactive impedance. The reactive impedance is controlled using specially designed coils and magnetic core. The internal coil is wound in the toroidal direction (across the z-axis) and creates a toroidal shape. A thin ferromagnetic strip is coiled on this toroidal shape in the poloidal direction to form the ferromagnetic core. Then, an external coil is wound on this ferromagnetic core in the poloidal direction. The internal coil is controlled by the inductive impedance of the external coil, which is related to the anisotropic properties of ferromagnetic strips. The internal coil is connected between the power supply line and a prosumer. This arrangement confirms the magnetic independence of coils and the symmetry of the current in the internal coil. The magnetic coupling between both coils is very low (~0.015–0.017) and appropriate for engineering applications. It is approved that the impedance of the internal coil is changed due to the anisotropic magnetic properties of the core material.
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Ohya, M., S. Imagawa, Y. Shirai, and H. Kobayashi. "Energization test apparatus of HTS coils cooled by liquid hydrogen and manufacture of split-type REBCO external field coil." Journal of Physics: Conference Series 2776, no. 1 (2024): 012010. http://dx.doi.org/10.1088/1742-6596/2776/1/012010.
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Abstract Liquid hydrogen (LH2) is a potential coolant of high-temperature superconducting (HTS) devices. However, owing to the high flammability of hydrogen and the risk of hydrogen embrittlement in materials, studies on LH2-cooled superconducting devices are rare. We developed an LH2 test apparatus to analyze the basic characteristics of LH2 as a coolant and evaluate the energizing characteristics of LH2-cooled superconducting wires. A REBCO external field coil was designed and manufactured for conducting cooling stability tests on various HTS coils cooled by LH2. The field coil, comprising eight single pancake coils of 4 mm wide REBCO wires, with inner diameter 106 mm and outer diameter 250 mm was divided into upper and lower sections. The test coil was placed in the central space. A magnetic field perpendicular to the test coil’s wire surface was generated by running currents in opposite directions through the upper and lower sections. Each double pancake coil was securely placed in a stainless-steel housing to withstand repulsive electromagnetic forces. The manufactured field coil was cooled using LH2, energized to 150 A, and successfully generated the intended magnetic field of 1.75 T. No increase in voltage was observed in any of the double pancake coils, and there was no mechanical degradation due to electromagnetic forces. Subsequently, we initiated thermal runaway tests on various HTS coils using the manufactured field coil to assess the cooling stability of LH2-cooled HTS coils. The study will facilitate the development of explosion-proof designs and safety technologies for LH2-cooled superconducting devices and cooling systems.
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Kwahk, Imjong, Kwang-Yeun Park, Ji-Young Choi, Hungjoo Kwon, and Changbin Joh. "Non-Destructive Evaluation for Sectional Loss of External Tendon of Prestressed Concrete Structures Using Total Flux Leakage." Applied Sciences 10, no. 21 (2020): 7398. http://dx.doi.org/10.3390/app10217398.
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A non-destructive evaluation method is proposed to identify the sectional loss of the external tendon of prestressed concrete structures by detecting the change of the magnetic flux in the external tendon exposed to a magnetic field. The method uses a solenoid-shaped device with two coils: a primary coil for producing magnetic field and secondary coil for damage detection, wrapping the external tendon. A current applied to the primary coil in the device causes the magnetic field. Then, the change in the magnetic flux by the damage in the external tendon is detected by the variation of the voltage in the secondary coil in the device as the device moves along the tendon. An alternating current is applied to the primary coil to minimize the effect of the moving speed of the device. As a result, the damaged area can be detected with a low-level energy current. In addition, a wrapping solenoid-shaped device that is easy to disassemble and assemble was developed for in situ inspection. The measured signal from the secondary coil has a sinusoidal form with the same frequency as the applied current to the primary coil, and the peak curve of the measured signal provides enough information to detect the damage. It is shown that the proposed method can quantitatively identify one or multiple damaged-tendon locations as well as damages of at least 2 cm.
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Chen, Wei, Rong Jin, Shuxin Wang, et al. "Influence of Fault Current and Different Oscillating Magnetic Fields on Electromagnetic–Thermal Characteristics of the REBCO Coil." Crystals 12, no. 12 (2022): 1688. http://dx.doi.org/10.3390/cryst12121688.
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When the high-temperature superconducting (HTS) REBCO (rare-earth barium copper oxide) coil is applied in a power system, a large amount of heat may be generated due to the short-circuiting of the system, resulting in the thermal instability of the coil. Moreover, under complex working conditions, the oscillating external magnetic field will further aggravate the coil quench. In this paper, the electromagnetic–thermal coupling model is used to analyze the loss, current distribution and temperature distribution of the REBCO coil under short-circuit fault conditions and oscillating external magnetic fields. In order to get closer to the actual situation, the modeling of the superconducting tape adopts the real tape structure, and the resistivity of the superconductor is described by the modified E-J relationship. Four cases are considered for the oscillating external magnetic field, i.e., sine, triangle, sawtooth and square cases. This model has certain significance as a reference for understanding the thermal stability of coils in extreme cases.
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Tan, Qinghua, Wenbin Zhang, Xiangyu Tan, Le Yang, Yanan Ren, and Yang Hu. "Design of Open-Ended Structure Wideband PCB Rogowski Coil Based on New Winding Method." Electronics 11, no. 3 (2022): 381. http://dx.doi.org/10.3390/electronics11030381.
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Compared with the traditional Rogowski coil, printed circuit board (PCB) Rogowski coil has the advantages of high measurement accuracy, simple manufacturing process and low cost. It has become an important device in current measurement. However, the existing PCB Rogowski coils are mostly closed, and the open-ended structure PCB Rogowski coils are susceptible to external magnetic field interference. This paper proposes an open-ended structure PCB Rogowski coil based on a new winding method, so that the two open-ended PCB Rogowski coils are evenly distributed when closed, while improving the coil’s immunity to external magnetic fields based on the winding method of equal area of the de-wired and loop. In addition, this paper uses the hybrid integration circuit and the back-end matching method to achieve the broadband measurement performance of the sensor. Finally, the experimental results show that the mutual inductance difference between the closed and open-ended structure PCB Rogowski coil is less than 0.5% under the same wiring mode. Under the equivalent current interference at 50 mm from the measured current, the maximum interference coefficient of the open-ended structure coil is 1.45%; in sine sweep and pulse current test conditions, the frequency band is 34 Hz–3.5 MHz.
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Sun, Danmei, Meixuan Chen, Symon Podilchak, et al. "Investigating flexible textile-based coils for wireless charging wearable electronics." Journal of Industrial Textiles 50, no. 3 (2019): 333–45. http://dx.doi.org/10.1177/1528083719831086.
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Smart and interactive textiles have been attracted great attention in recent years. This research explored three different techniques and processes in developing textile-based conductive coils that are able to embed in a garment layer. Coils made through embroidery and screen printing have good dimensional stability, although the resistance of screen printed coil is too high due to the low conductivity of the print ink. Laser cut coil provided the best electrical conductivity; however, the disadvantage of this method is that it is very difficult to keep the completed coil to the predetermined shape and dimension. The tested results show that an electromagnetic field has been generated between the textile-based conductive coil and an external coil that is directly powered by electricity. The magnetic field and electric field worked simultaneously to complete the wireless charging process.
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Silverio, Vania, Miguel Amaral, João Gaspar, Susana Cardoso, and Paulo P. Freitas. "Manipulation of Magnetic Beads with Thin Film Microelectromagnet Traps." Micromachines 10, no. 9 (2019): 607. http://dx.doi.org/10.3390/mi10090607.
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Integration of point-of-care assays can be facilitated with the use of actuated magnetic beads (MB) to perform testing in less expensive settings to enable the delivery of cost-effective care. In this paper we present six different designs of planar microelectromagnets traps (MEMT) with four external coils in series and one central coil connected for an opposite direction of manipulation of MB in microfluidic flows. The development of a simulation tool facilitated the rapid and efficient optimization of designs by presenting the influence of system variables on real time concentrations of MB. Real time experiments are in good agreement with the simulations and showed that the design enabled synchronous concentration and dispersion of MB on the same MEMT. The yield of local concentration is seen to be highly dependent on coil design. Additional coil turns between the central and external coils (inter-windings) doubled magnetic concentration and repulsion with no significant electrical resistance increase. The assemblage of a copper microchannel closed loop cooling system to the coils successfully eliminated the thermal drift promoted by joule heating generated by applied current.
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Annino, G., H. Moons, M. Fittipaldi, S. Van Doorslaer, and E. Goovaerts. "High-Field Pulsed ENDOR with Intra-cavity Radiofrequency Coil." Applied Magnetic Resonance 51, no. 11 (2020): 1433–49. http://dx.doi.org/10.1007/s00723-020-01269-z.
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AbstractThis study compares the performance of two coil configurations for W-band pulsed ENDOR using a setup with both a radiofrequency ‘hairpin’ coil internal to a microwave non-radiative resonator and Helmholtz-like coils external to the resonator. Evaluation of the different coil performances is achieved via the ENDOR study of two model systems. The efficiencies of the coil configurations are first investigated numerically, showing that a higher radiofrequency current-to-magnetic field conversion factor can be achieved with the intra-cavity coil, with a similar radiofrequency magnetic field uniformity. This result is then confirmed by the broadband ENDOR spectra acquired with the two coil arrangements. A gain in the signal-to-noise ratio enabled by the internal coil of about a factor 10 was observed. In some cases, the high conversion factor of the intra-cavity coil led to a saturation of the ENDOR transitions. The possibility to implement a similar intra-cavity radiofrequency coil configuration in higher field spectrometers is finally discussed.
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Dan Li and Haifeng Liu. "Magnetic configurations of Chinese First Quasi-axisymmetric Stellarator influenced by coil perturbations." Acta Physica Sinica 74, no. 5 (2025): 0. https://doi.org/10.7498/aps.74.20241606.
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Deviations of stellarator coils during fabrication and assembly are inevitable, which result in error fields. The magnetic configurations in stellarators are dominantly generated by external coils, sensitive to these error fields. Therefore, it is essential to estimate impacts of coil deformations on a stellarator magnetic topology. This paper is dedicated to studying the influence of deformations of nonplanar modular coils (MC) on the magnetic topology in Chinese First Quasi-axisymmetric Stellarator (CFQS). In this work, by changing the Fourier coefficients that represent the CCS and the coil, we obtain two types of deformation coils, i.e., "in-surface" and "out-surface" perturbations on each MC. Subsequently, we utilize three kinds of magnetic islands with rotational transformsι= 2/4, 2/5, and 2/6 to identify coil deviations that have a significant impact on the CFQS magnetic configuration. Serval important results are achieved: (ⅰ) the same deformation of a coil gives rise to various resonant error fields, and the amplitudes of these error fields are different. (ⅱ) The sensitivity of a resonant error field to the deformation of each coil is different. Local deviations of the most complex coil may lead to indistinctive impacts on the magnetic topology. (ⅲ) Resonant error fields are more sensitive to broad perturbations of a coil than local perturbations. These results address that the relaxation of specific coil tolerances is expected to decrease engineering constraints of coil design and fabrication. In addition, this work also helps develop a precise computational model for the forthcoming mapping experiments of magnetic configurations in CFQS.
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Salar Elahi, A., and M. Ghoranneviss. "Application of multipole moments and magnetic techniques for determination of tokamak plasma shift." Journal of Plasma Physics 80, no. 1 (2013): 9–25. http://dx.doi.org/10.1017/s0022377813000834.
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AbstractIn this contribution, we presented approaches for the determination of tokamak plasma column shift based on multipole moments and magnetic techniques. First, we presented analytical details for using this technique. Then, the principle of different models based on this technique for the design and fabrication of six coils will be presented: four modified Rogowski coils (two cosine coils and two sine coils) and two saddle coils (saddle sine coil and saddle cosine coil). Also, to compare the results, the flux loops technique is used. Because of continuous measurements of magnetic field distribution around the tokamak plasma using multipole coils, this technique gives us more reliable information about the plasma current displacement. Moreover, we deduced the plasma current and plasma boundary centers shift using the two semi-empirical techniques in the IR-T1 tokamak. First, the plasma current center is calculated from the vertical field coil characteristics. The calculation is made focusing on the vertical field coil current and voltage changes due to a horizontal displacement of the plasma column. Also, the plasma boundary center shift was measured from the external magnetic coils. The results from these two techniques are compared and discussed.
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Sano, Hiroki, Mitsuaki Toda, Takahiro Sugihara, Naoyuki Uchiyama, Jun-ichiro Hamada, and Hiroo Iwata. "Coils Coated With the Cyclic Peptide SEK-1005 Accelerate Intra-aneurysmal Organization." Neurosurgery 67, no. 4 (2010): 984–92. http://dx.doi.org/10.1227/neu.0b013e3181eb95da.
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Abstract BACKGROUND: Although the treatment of intracranial aneurysms with detachable coils is now widely accepted, the problem of coil compaction and recanalization remains to be solved. OBJECTIVE: To prevent recanalization by inducing intra-aneurysmal organization through prepared platinum coils coated with a novel cyclic peptide, SEK-1005, which can accelerate wound healing. METHODS: Using a rat aneurysm model, we examined the tissue response to these coils. An SEK-1005–coated coil (SC) or unmodified coil was inserted into the ligated external carotid artery (ECA) sac of rats. The sacs were removed on day 14 or 42 after coil insertion and subjected to conventional and immunohistochemical examination. We evaluated the tissue response in the ECA sacs and compared the percentage of organized areas in the ECA sacs of rats with SCs and unmodified coils. RESULTS: In SC rats, tissue organization was accelerated and the proliferation of α-smooth muscle actin- and vimentin-positive cells was promoted. On days 14 and 42, tissue organization was significantly greater in the ECA sacs of rats with SCs. CONCLUSION: SCs accelerated intra-aneurysmal organization in our rat aneurysm model suggesting that platinum coils coated with the novel cyclic peptide SEK-1005 may prevent recanalization and improve the clinical outcome in patients treated by coil embolization.
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Ding, W. J., H. Y. Li, and H. Y. Zhang. "Research on the influence of each interference factor on the testing accuracy of pulse current sensor and improvement method." Journal of Physics: Conference Series 2891, no. 9 (2024): 092013. https://doi.org/10.1088/1742-6596/2891/9/092013.
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Abstract The excellent performance of rogowski coils is often used as current sensors during transient pulse high current testing. In order to ensure the accuracy of the measurements, it is necessary to consider the influence that various factors may have on the results in practical applications. Rogowski coil structure, external magnetic field interference, current-carrying conductor installation position, the size of the current-carrying conductor and other interfering factors are quantitatively analyzed, and measures are proposed to improve the accuracy of Rogowski coil measurement. The analyses show that each of the interfering factors affects the accuracy of the rogowski coil to some extent. Among them, the interfering magnetic field perpendicular to the plane of the rogowski coil has the greatest effect.
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Alghrairi, Mokhalad, Nasri Sulaiman, Wan Zuha Wan Hasan, Haslina Jaafar, and Saad Mutashar. "Efficient wireless power transmission to remote the sensor in restenosis coronary artery." Indonesian Journal of Electrical Engineering and Computer Science 25, no. 2 (2022): 771. http://dx.doi.org/10.11591/ijeecs.v25.i2.pp771-779.
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In this study, the researchers have proposed an alternative technique for designing an asymmetric 4 coil-resonance coupling module based on the series-to-parallel topology at 27 MHz industrial scientific medical (ISM) band to avoid the tissue damage, for the constant monitoring of the in-stent restenosis coronary artery. This design consisted of 2 components, i.e., the external part that included 3 planar coils that were placed outside the body and an internal helical coil (stent) that was implanted into the coronary artery in the human tissue. This technique considered the output power and the transfer efficiency of the overall system, coil geometry like the number of coils per turn, and coil size. The results indicated that this design showed an 82% efficiency in the air if the transmission distance was maintained as 20 mm, which allowed the wireless power supply system to monitor the pressure within the coronary artery when the implanted load resistance was 400 Ω.
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Mokhalad, Alghrairi1 3., Sulaiman1 Nasri, Zuha Wan Hasan1 Wan, Jaafar1 Haslina, and Mutashar2 Saad. "Efficient wireless power transmission to remote the sensor in restenosis coronary artery." Indonesian Journal of Electrical Engineering and Computer Science 25, no. 2 (2022): 771–79. https://doi.org/10.11591/ijeecs.v25.i2.pp771-779.
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In this study, the researchers have proposed an alternative technique for designing an asymmetric 4 coil-resonance coupling module based on the series-to-parallel topology at 27 MHz industrial scientific medical (ISM) band to avoid the tissue damage, for the constant monitoring of the in-stent restenosis coronary artery. This design consisted of 2 components, i.e., the external part that included 3 planar coils that were placed outside the body and an internal helical coil (stent) that was implanted into the coronary artery in the human tissue. This technique considered the output power and the transfer efficiency of the overall system, coil geometry like the number of coils per turn, and coil size. The results indicated that this design showed an 82% efficiency in the air if the transmission distance was maintained as 20 mm, which allowed the wireless power supply system to monitor the pressure within the coronary artery when the implanted load resistance was 400 Ω.
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Nagarajan, Rajakumar, Daniel JA Margolis, Steven S. Raman, et al. "Mr Spectroscopic Imaging of Peripheral Zone in Prostate Cancer Using a 3t Mri Scanner: Endorectal versus External Phased Array Coils." Magnetic Resonance Insights 6 (January 2013): MRI.S10861. http://dx.doi.org/10.4137/mri.s10861.
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Magnetic resonance spectroscopic imaging (MRSI) detects alterations in major prostate metabolites, such as citrate (Cit), creatine (Cr), and choline (Ch). We evaluated the sensitivity and accuracy of three-dimensional MRSI of prostate using an endorectal compared to an external phased array “receive” coil on a 3T MRI scanner. Eighteen patients with prostate cancer (PCa) who underwent endorectal MR imaging and proton (1H) MRSI were included in this study. Immediately after the endorectal MRSI scan, the PCa patients were scanned with the external phased array coil. The endorectal coil-detected metabolite ratio [(Ch+Cr)/Cit] was significantly higher in cancer locations (1.667 ± 0.663) compared to non-cancer locations (0.978 ± 0.420) ( P < 0.001). Similarly, for the external phased array, the ratio was significantly higher in cancer locations (1.070 ± 0.525) compared to non-cancer locations (0.521 ± 0.310) ( P < 0.001). The sensitivity and accuracy of cancer detection were 81% and 78% using the endorectal ‘receive’ coil, and 69% and 75%, respectively using the external phased array ‘receive’ coil.
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Qu, Mei Ling, Xin Zhi Shi, Chang Qi, and Gao Feng Wang. "Analysis and Simulation of Wireless Power Transfer System Based on Magnetic Resonances." Advanced Materials Research 516-517 (May 2012): 1737–41. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1737.
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Wireless power transfer brings the possibility of connector-free for electric devices. Because there is no electric connection between power source and load, the system employs wireless power transfer based on magnetic resonance becomes safer, more convenient and more reliable. The wireless power transfer system of four-coils based on magnetic resonances is analyzed, including phenomenon of frequency splitting, effect of the angle between the source coil and the device coil, and effect of external objects. Simulation results are presented in this paper.
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Pahlavan, Saeideh, Mostafa Shooshtari, Mohammadreza Maleki, and Shahin Jafarabadi Ashtiani. "Using Overlapped Resonators in Wireless Power Transfer for Uniform Electromagnetic Field and Removing Blank Spots in Free Moving Applications." Electronics 11, no. 8 (2022): 1204. http://dx.doi.org/10.3390/electronics11081204.
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We propose an induction link based on overlapping arrays to eliminate blank spots on the electromagnetic field for moving object applications. We use two arrays of four aligned coils that have a 50% overlap between the two plates. This mechanism compensates for the internal coil power drop at positions in the boundaries between two adjacent external coils. We showed that if these plates are excited, a uniform electromagnetic field is created in the movement direction of the moving object. This uniform electromagnetic field distribution will result in a constant receiving power at all points in the path of the moving internal coil with the same power consumption of one coil excitation. Power delivery to the moving object tolerance reaches 10% at most, while, in non-overlapped scenarios, it is approximately 50%. In addition, according to the theoretical calculations, printed circuit coils (PCB) for the array are designed for maximum efficiency. We found that the change in distance and dimensions of the receiver coil has a linear effect on power and efficiency. Moreover, a Specific Absorption Rate (SAR) simulation was performed for biocompatibility. In this paper, we investigate and record a 68% electrical power efficiency for the fabricated system. The array consists of eight transmitters coils of the same size and shape and a receiver coil at a distance of 4 cm. Furthermore, the fabricated coil has shown improved efficiency compared to similar studies in the literature and introduces a promising structure for bio-test applications.
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Mohanarangam, Krithikaa, Yellappa Palagani, and Jun Choi. "Evaluation of Specific Absorption Rate in Three-Layered Tissue Model at 13.56 MHz and 40.68 MHz for Inductively Powered Biomedical Implants." Applied Sciences 9, no. 6 (2019): 1125. http://dx.doi.org/10.3390/app9061125.
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This paper presents an optimized 3-coil inductive wireless power transfer (WPT) system at 13.56 MHz and 40.68 MHz to show and compare the specific absorption rate (SAR) effects on human tissue. This work also substantiates the effects of perfect alignment, lateral and/or angular misalignments on the power transfer efficiency (PTE) of the proposed WPT system. Additionally, the impacts of different tissue composition, input power and coil shape on the SAR are analyzed. The distance between the external and implantable coils is 10 mm. The results have been verified through simulations and measurements. The simulated results show that the SAR of the system at 40.68 MHz had crossed the limit designated by the Federal Communications Commission and hence, it is unsafe and causes tissue damage. Measurement results of the system in air medium show that the optimized printed circuit board coils at 13.56 MHz achieved a PTE of 41.7% whereas PTE waned to 18.2% and 15.4% at 10 mm of lateral misalignment and 60° of angular misalignment respectively. The PTE of a combination of 10 mm lateral misalignment and 60° angular misalignment is 21%. To analyze in a real-environment, a boneless pork sample with 10 mm of thickness is placed as a medium between the external and implantable coils. At perfect alignment, the PTE through pork sample is 30.8%. A RF power generator operating at 13.56 MHz provides 1 W input power to the external coil and the power delivered to load through the air and tissue mediums are 347 mW and 266 mW respectively.
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Wilseck, Zachary, Luis Savastano, Neeraj Chaudhary, et al. "Republished: Delayed extrusion of embolic coils into the airway after embolization of an external carotid artery pseudoaneurysm." Journal of NeuroInterventional Surgery 10, no. 7 (2018): e18-e18. http://dx.doi.org/10.1136/neurintsurg-2017-013178.rep.
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Carotid blowout syndrome (CBS) is a known devastating complication of head and neck surgery. The risk of developing CBS increases in the setting of radiation therapy, wound breakdown, or tumor recurrence. Traditionally, the treatment of choice for CBS is surgical ligation of the bleeding artery; however, recently, endovascular occlusion has become a more common option. If a pseudoaneurysm is present, treatment consists of trapping with endovascular coils or occlusion with a liquid embolic agent. Delayed migration of embolization coils into the airway causing acute respiratory distress is a rare occurrence. This report presents a case of a 57-year-old woman who presented to her otolaryngologist after experiencing an episode of acute respiratory distress which resolved when she expectorated embolization coil material from her tracheostomy tube. Three months prior to the episode she underwent coil embolization of an external carotid artery pseudoaneurysm for life-threatening hemorrhage.
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Kováč, P., L. Kopera, T. Melišek, et al. "Water ice-cooled MgB2 coil made by wind and react process." Superconductor Science and Technology 35, no. 5 (2022): 055001. http://dx.doi.org/10.1088/1361-6668/ac521c.
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Abstract A wind and react (W&R) coil of inner diameter 53 mm has been made from multi-core MgB2/Nb/CuNi wire manufactured by the internal magnesium diffusion (IMD) process. The W&R coil is wound from non-insulated rectangular wire of 1 mm2 with only 5 µm thick stainless steel foil used for interlayer insulation. The transport current performance of the coil and short wire samples was measured in a liquid He bath at external magnetic fields of 4.5–8.5 T and also in self-field conditions in sub-cooled water ice at temperatures between 33 K and 38 K. The presented MgB2 coil exhibits stable behavior at water ice cooling, and its high space factor allows a high current density of winding in comparison to the data from the already published MgB2 coils. The presented results demonstrate that MgB2 windings can be used safely in He-free conditions inside sub-cooled water ice, and this technique can be further optimized and used for future MgB2 coils.
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Takahashi, Ryo, Wakako Yukita, Takuya Sasatani, Tomoyuki Yokota, Takao Someya, and Yoshihiro Kawahara. "Twin Meander Coil." Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 5, no. 4 (2021): 1–21. http://dx.doi.org/10.1145/3494996.
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Energy-efficient and unconstrained wearable sensing platforms are essential for ubiquitous healthcare and activity monitoring applications. This paper presents Twin Meander Coil for wirelessly connecting battery-free on-body sensors to a textile-based reader knitted into clothing. This connection is based on passive inductive telemetry (PIT), wherein an external reader coil collects data from passive sensor coils via the magnetic field. In contrast to standard active sensing techniques, PIT does not require the reader to power up the sensors. Thus, the reader can be fabricated using a lossy conductive thread and industrial knitting machines. Furthermore, the sensors can superimpose information such as ID, touch, rotation, and pressure on its frequency response. However, conventional PIT technology needs a strong coupling between the reader and the sensor, requiring the reader to be small to the same extent as the sensors' size. Thus, applying this technology to body-scale sensing systems is challenging. To enable body-scale readout, Twin Meander Coil enhances the sensitivity of PIT technology by dividing the body-scale meander-shaped reader coils into two parts and integrating them so that they support the readout of each other. To demonstrate its feasibility, we built a prototype with a knitting machine, evaluated its sensing ability, and demonstrated several applications.
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Ben Fadhel, Yosra, Ghada Bouattour, Douha Bouchaala, Nabil Derbel, and Olfa Kanoun. "Model-Based Optimization of Spiral Coils for Improving Wireless Power Transfer." Energies 16, no. 19 (2023): 6886. http://dx.doi.org/10.3390/en16196886.
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Inductive wireless power transfer is a promising technology for powering smart wearable devices. The spiral coil shape is widely used in wireless power transfer applications. Nevertheless, during the coil design process, there are many challenges to overcome considering all the design constraints. The most important is to determine the optimal coil parameters (internal radius, external radius, spacing, wire width, and conductive wire) with the aim of obtaining the highest coil quality factor. Coil modeling is very important for the wireless power transfer system’s efficiency. Indeed, it is challenging because it requires a high computational effort and has convergence problems. In this paper, we propose a new approach for the approximation of spiral coils through concentric circular turns to reduce the computational effort. The mathematical model determines the optimal coil parameters to obtain the highest coil quality factor. We have chosen the smart textile as an application. The system operates at a frequency of 100 Khz considering the Qi guidelines. To validate this approach, we compared the approximated circular coil model with the spiral coil model through a finite element method simulation using the COMSOL software. The obtained results show that the proposed approximation reduces the complexity of the coil design process and performs well compared to the model corresponding to the spiral shape, without significantly modifying the coil inductance. For a wire width smaller than 1 mm, the total deviation is around 4% in terms of the coil quality factor in a predetermined domain of its parameters.
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Luo, Jie, Ruifeng Xue, Jiahao Cheong, Xuan Zhang, and Lei Yao. "Design and Optimization of Planar Spiral Coils for Powering Implantable Neural Recording Microsystem." Micromachines 14, no. 6 (2023): 1221. http://dx.doi.org/10.3390/mi14061221.
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This paper presents a design and optimization method utilizing inductive coupling coils for wireless power transfer in implantable neural recording microsystems, aiming at maximizing power transfer efficiency, which is essential for reducing externally transmitted power and ensuring biological tissue safety. The modeling of inductive coupling is simplified by combining semi-empirical formulations with theoretical models. By introducing the optimal resonant load transformation, the coil optimization is decoupled from an actual load impedance. The complete design optimization process of the coil parameters is given, which takes the maximum theoretical power transfer efficiency as the objective function. When the actual load changes, only the load transformation network needs to be updated instead of rerunning the entire optimization process. Planar spiral coils are designed to power neural recording implants given the challenges of limited implantable space, stringent low-profile restrictions, high-power transmission requirements and biocompatibility. The modeling calculation, electromagnetic simulation and measurement results are compared. The operating frequency of the designed inductive coupling is 13.56 MHz, the outer diameter of the implanted coil is 10 mm and the working distance between the external coil and the implanted coil is 10 mm. The measured power transfer efficiency is 70%, which is close to the maximum theoretical transfer efficiency of 71.9%, confirming the effectiveness of this method.
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Keysan, Ozan, and Bülent Ertan. "Determination of rotor slot number of an induction motor using an external search coil." Facta universitatis - series: Electronics and Energetics 22, no. 2 (2009): 227–34. http://dx.doi.org/10.2298/fuee0902227k.
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This paper describes determination of the number rotor slots of an induction motor from the induced emf in an external search coil. This information is needed in prediction of motor speed from the external search coil induced voltage. The approach is based on identifying saliency harmonics and rotor slot harmonics, via FFT analysis of the external search coil emf. The proposed approach is tested on an induction motor driven by the mains supply. The experiments are repeated with a PWM supply. It is shown that the method works well in both cases and the number of rotor slots of the test machine is accurately predicted. .
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Ma, Rong Hua, and Jian Hao Zhong. "Design and Fabrication of a Micro-Actuator Based on Electromagnetic Membrane Device." Advanced Materials Research 488-489 (March 2012): 1451–56. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.1451.
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The purpose of this study is to develop a micro electro-magnetic actuator manufactured by MEMS-based fabrication and electroplating techniques. This actuator presented a novel technique in the electromagnetic fabrication and smaller physical size than the traditional counterparts for micro actuators and provides a faster response time and lower cost. A micro coil structure is released from FeCl3 etchant and bonded on a thin film (Parafilm”M”, Pechiney Plastic Packaging Inc.) to achieve an actuator-membrane structure. When an external AC power is applied to a micro coil, a magnetic field is created to attract and repel through an NdFeB permanent magnet, and the displacement of the membrane is increased as a current of AC power. The results show the measured magnetic field intensity weakens as the distance between the coil and the Gauss meter probe increases. However, it is observed that the magnetic field intensity does not increase linearly with the number of series coils, which is due to the distance between series coils.
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Lee, Jaejoon, and Jaewook Lee. "Magnetic Force Enhancement Using Air-Gap Magnetic Field Manipulation by Optimized Coil Currents." Applied Sciences 10, no. 1 (2019): 104. http://dx.doi.org/10.3390/app10010104.
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This paper presents an air-gap magnetic field manipulation by optimized coil currents for a magnetic force enhancement in electromechanical devices. The external coil is designed near the device air-gap for manipulating the magnetic field distribution. The distribution of external coil currents is then optimized for maximizing the magnetic force in the tangential direction to the air-gap line. For the optimization, the design domain near air-gap is divided into small areas, and design variables are assigned at each small design area. The design variables determines not only the strength of coil current density (i.e., number of coil turns) but also whether the material state is coil or iron. In a benchmark actuator example, it is shown that 11.12% force enhancement is available by manipulating the air-gap magnetic field distribution using the optimized coil current. By investigating the magnetic field distribution, it is confirmed that the optimized coil current manipulated the magnetic field, forwarding a focused and inclined distribution that is an ideal distribution for maximizing the magnetic force.
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Kim, Chan, Jiyun Nan, Kim Tien Nguyen, Jong-Oh Park, Eunpyo Choi, and Jayoung Kim. "Non-FFP-Based Magnetic Particle Imaging (NFMPI) with an Open-Type RF Coil System: A Feasibility Study." Sensors 25, no. 3 (2025): 665. https://doi.org/10.3390/s25030665.
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Active drug delivery systems for cancer therapy are gaining attention for their biocompatibility and enhanced efficacy compared to conventional chemotherapy and surgery. To improve precision in targeted drug delivery (TDD), actuating devices using external magnetic fields are employed. However, a key challenge is the inability to visually track magnetic drug carriers in blood vessels, complicating navigation to the target. Magnetic particle imaging (MPI) systems can localize magnetic carriers (MCs) but rely on bulky electromagnetic coils to generate a static magnetic field gradient, creating a field-free point (FFP) within the field of view (FOV). Also, additional coils are required to move the FFP across the FOV, limiting flexibility and increasing the system size. To address these issues, we propose a non-FFP-based, open-type RF coil system with a simplified structure composed of a Tx/Rx coil and a permanent magnet at the coil center, eliminating the need for an FFP. Furthermore, integrating a robotic arm for coil assembly enables easy adjustment of the FOV size and location. Finally, imaging tests with magnetic nanoparticles (MNPs) confirmed the system’s ability to detect and localize a minimum mass of 0.3 mg (Fe) in 80 × 80 mm2.
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Inoue, Nagisa, Yoshihiko Koya, Norihisa Miki, and Hiroaki Onoe. "Graphene-Based Wireless Tube-Shaped Pressure Sensor for In Vivo Blood Pressure Monitoring." Micromachines 10, no. 2 (2019): 139. http://dx.doi.org/10.3390/mi10020139.
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We propose a wireless pressure sensor composed of a graphene sheet and a transmitter coil integrated with a polydimethylsiloxane (PDMS) tube. The pressure inside the tube was monitored wirelessly using an external receiver coil. We then monitored the typical blood pressure range, 12–20 kPa, using this fabricated sensor by changing the turn number of the receiver coil and the overlapping length of the coils. Furthermore, we demonstrated wireless blood pressure measurement by connecting our sensor to the blood vessel of a rat. Our results suggested that this sensor can be easily inserted between an implantable medical device and blood vessels for in vivo blood pressure monitoring. The proposed wireless pressure sensor could also be suitable for monitoring in vivo implanted medical systems, such as artificial organs and pump systems.
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Arbustini, Johan, Johanna Muñoz, Huxi Wang, et al. "MEMS Magnetic Field Source for Frequency Conversion Approaches for ME Sensors." Current Directions in Biomedical Engineering 8, no. 2 (2022): 309–12. http://dx.doi.org/10.1515/cdbme-2022-1079.
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Abstract Some magnetoelectric sensors require predefined external magnetic fields to satisfy optimal operation depending on their resonance frequency. While coils commonly generate this external magnetic field, a microelectromechanical systems (MEMS) resonator integrated with permanent magnets could be a possible replacement. In this proof-of-concept study, the interaction of a MEMS resonator and the ME sensor is investigated and compared with the standard approach to achieve the best possible sensor operation in terms of sensitivity. The achievable sensor sensitivity was evaluated experimentally by generating the magnetic excitation signal by a coil or a small-sized MEMS resonator. Moreover, the possibility of using both approaches simultaneously was also analysed. The MEMS resonator operated with 20Vppat 1.377 kHz has achieved a sensor sensitivity of 221.21mV/T. This sensitivity is comparable with the standard approach, where only a coil for sensor excitation is used. The enhanced sensitivity of 277.0mV/T could be identified by generating the excitation signal simultaneously by a coil and the MEMS resonator in parallel. In conclusion, these MEMS resonator methods can potentially increase the sensitivity of the ME sensor even further. The unequal excitation frequency of the MEMS resonator and the resonance frequency of the ME sensor currently limit the performance. Furthermore, the MEMS resonator as a coil replacement also enables the complete sensor system to be scaled down. Therefore, optimizations to match both frequencies even better are under investigation.
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Seungyong Hahn, Youngjae Kim, Jiayin Ling, et al. "No-Insulation Coil Under Time-Varying Condition: Magnetic Coupling With External Coil." IEEE Transactions on Applied Superconductivity 23, no. 3 (2013): 4601705. http://dx.doi.org/10.1109/tasc.2013.2240756.
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Ueno, J., and N. Tohma. "Endovascular Treatment of Cerebral Aneurysm with Coils and Onyx." Interventional Neuroradiology 10, no. 1_suppl (2004): 51–56. http://dx.doi.org/10.1177/15910199040100s106.
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We investigated endovascular treatment of cerebral aneurysm by coil and Onyx in vivo experiment in order to promote the advantages of coil embolization,. The aim of this study was to clarify the advantages and problems of coil and Onyx embolization and to evaluate its potentials for application in clinical medicine. We set experimental aneurysms made of external jugular vein to bilateral carotid arteries of 10 Beagle dogs and embolized aneurysm with coils and Onyx. Two months later, the dogs were sacrificed and took out the experimental aneurysms and examined them histologically. We have experienced Onyx migration into the vessel at the beginning of our experiment. Technical problems were as follows; Onyx was not easily visible on DSA monitor particularly in tight coil packing. Catheter tip was often stuck to the Onyx in the aneurysm. Protect balloon could not completely protect the Onyx leakage into the vessel. Microscopic examinations were as follows; The aneurysm was filled with Onyx, coils, and inflammatory reactants. The orifice of the aneurysm was packed with augmented fibrous tissue. This method increased contact between the aneurysm wall and coils. Onyx filled the intra-aneurismal space more tightly. Coils prevented Onyx from flowing out into the vessel. In Onyx, intimal layer was more rapidly formed at the neck of the aneurysm than coils only. The most important problems during Onyx embolization is how to prevent Onyx migration into the vessel. We should like to propose the guideline for Onyx embolization.
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Simonazzi, Mattia, Leonardo Sandrolini, and Andrea Mariscotti. "Resonator Arrays for Linear Position Sensors." Journal of Low Power Electronics and Applications 13, no. 2 (2023): 41. http://dx.doi.org/10.3390/jlpea13020041.
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A contactless position sensor based on an array of magnetically coupled resonators and an external single coil cell is discussed for both stationary and dynamic applications. The simple structure allows the sensor to be adapted to the system in which it is installed and can be used to detect the positions of objects in motion that bear an external resonator coil that does not necessitate a supply. By exploiting the unique behaviour of the array input impedance, it is possible to identify the position of the external resonator by exciting the first array cell with an external voltage source and measuring the resulting input current. The system is robust and suitable for application in harsh environments. The sensitivity of the measured input impedance to the space variation is adjustable with the definition of the array geometry and is analysed. Different configurations of the array and external resonator are considered, and the effects of various termination conditions and the resulting factor of merit after changing the coil resistance are discussed. The proposed procedure is numerically validated for an array of ten identical magnetically coupled resonators with 15 cm side lengths. Simulations carried out for a distance of up to 20 cm show that, with a quality factor lower than 100 and optimal terminations of both the array and external coil, it is possible to detect the position of the latter.
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Berikov, D., G. Ahmadov, Yu Kopatch, and V. Novitsky. "Magnetic system for controlling the spin of polarized neutrons." Journal of Instrumentation 17, no. 08 (2022): P08030. http://dx.doi.org/10.1088/1748-0221/17/08/p08030.
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Abstract A spin control magnetic system was developed and assembled at the JINR Laboratory of Neutron Physics (Dubna, Russia) and was tested with a beam of polarized neutrons at the POLI instrument of the FRM II reactor in Garching (Germany). This paper presents the principle of operation and a method for compensating the influence of external magnetic fields on polarization using this device. The system consists of three precession coils in a magnetic screen. The first coil allows, by changing the current in it, to ensure the rotation of the neutron spin by an arbitrary angle relative to the magnetic field inside the coil. The remaining two coils are designed to compensate for the effect of scattered magnetic fields on the beam polarization, and to preserve the polarization vector direction.
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Bai, Hongyu, W. Markiewicz, Jun Lu, and Hubertus Weijers. "Thermal Conductivity Test of YBCO Coated Conductor Tape Stacks Interleaved With Insulated Stainless Steel Tapes." Applied Superconductivity, IEEE Transactions on 23, no. 3 (2012): 4600204. http://dx.doi.org/10.1109/tasc.2012.2229774.
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A 32 Tesla, all-superconducting user magnet, which consists of two high temperature superconductor YBCO inner coils producing a field of 17 T in an low temperature superconductor Nb3Sn and NbTi outer magnet producing a background field of 15 T, is being developed at the National High Magnetic Field Laboratory. The YBCO inner coils are pancake-wound with YBCO coated conductor tapes with an interleaved insulation of sol-gel coated stainless steel tapes. The coils are to be cooled directly in liquid helium bath. Heat losses in the windings, such as ac losses during ramping and heat loss in the internal joints, are supposed to be transferred to the coil external surfaces through heat conduction. Thus, thermal conductivity of the coil structure is critical for the internal cooling of the coil and also quench propagation if any. Thermal conductivity measurements were carried out in the radial direction on stacks of alternating YBCO tapes and stainless steel tapes. This paper presents the test results that showed a very low thermal conductivity in the radial direction. For comparison purposes, calculated thermal conductivities in the axial and azimuthal direction are also presented.
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Fassnacht, W., F. Hammer, Q. Gardiner, and G. Desuter. "Delayed endovascular coil extrusion after embolisation for post-tonsillectomy haemorrhage: case report and literature review." Journal of Laryngology & Otology 127, no. 1 (2012): 88–91. http://dx.doi.org/10.1017/s0022215112002599.
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AbstractObjective:To report a rare case of delayed endovascular coil extrusion following embolisation of a lingual artery pseudoaneurysm.Case report:A 23-year-old woman presented with dysphagia and odynophagia 11 months after having experienced massive post-tonsillectomy haemorrhage. At that time, the bleeding had been stopped by embolisation of a lingual artery pseudoaneurysm and the external carotid artery. Clinical examination at admission showed extrusion of the embolisation coils in the lateral lower pharyngeal wall. The coils were removed under general anaesthesia in the presence of an interventional radiologist. The procedure and post-operative period were without complication and no bleeding was observed. The dysphagia and pain disappeared and the subsequent seven-month follow-up period was uneventful.Conclusion:Although selective embolisation is a safe and effective treatment for severe post-tonsillectomy haemorrhage, the possibility of delayed coil extrusion should be kept in mind.
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Farooq, Muhammad, Bilal Amin, Marcin J. Kraśny, et al. "An Ex Vivo Study of Wireless Linkage Distance between Implantable LC Resonance Sensor and External Readout Coil." Sensors 22, no. 21 (2022): 8402. http://dx.doi.org/10.3390/s22218402.
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The wireless monitoring of key physiological parameters such as heart rate, respiratory rate, temperature, and pressure can aid in preventive healthcare, early diagnosis, and patient-tailored treatment. In wireless implantable sensors, the distance between the sensor and the reader device is prone to be influenced by the operating frequency, as well as by the medium between the sensor and the reader. This manuscript presents an ex vivo investigation of the wireless linkage between an implantable sensor and an external reader for medical applications. The sensor was designed and fabricated using a cost-effective and accessible fabrication process. The sensor is composed of a circular planar inductor (L) and a circular planar capacitor (C) to form an inductor–capacitor (LC) resonance tank circuit. The reader system comprises a readout coil and data acquisition instrumentation. To investigate the effect of biological medium on wireless linkage, the readout distance between the sensor and the readout coil was examined independently for porcine and ovine tissues. In the bench model, to mimic the bio-environment for the investigation, skin, muscle, and fat tissues were used. The relative magnitude of the reflection coefficient (S11) at the readout coil was used as a metric to benchmark wireless linkage. A readable linkage signal was observed on the readout coil when the sensor was held up to 2.5 cm under layers of skin, muscle, and fat tissue. To increase the remote readout distance of the LC sensor, the effect of the repeater coil was also investigated. The experimental results showed that the magnitude of the reflection coefficient signal was increased 3–3.5 times in the presence of the repeater coil, thereby increasing the signal-to-noise ratio of the detected signal. Therefore, the repeater coil between the sensor and the readout coil allows a larger sensing range for a variety of applications in implanted or sealed fields.
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Elshawesh, F., H. Mahfud, A. Abdurrahim, and F. Elhaddad. "Role of Surface Finish in Fatigue Failure of Type 316L Stainless Steel Coil Tube." Materials Performance 47, no. 8 (2008): 70–73. https://doi.org/10.5006/mp2008_47_8-70.
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A Type 316L stainless steel (UNS S31603) coil tube used for dehydration of wet gas with tri-ethylene glycol cracked and failed after less than one year of service in a platform gas processing facility. The investigation revealed multiple fatigue cracks at a plastically deformed area on the coil external surface. Vibration of the coil tube during service caused the cracking.
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Mechefske, Chris K., G. Yao, and Fenglin Wang. "Vibration and Acoustic Noise Characterization of a Gradient Coil Insert in a 4 T MRI." Journal of Vibration and Control 10, no. 6 (2004): 861–80. http://dx.doi.org/10.1177/1077546304040948.
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High magnetic field strength and high-speed gradient coil current switching are becoming ever more commonplace in magnetic resonance imaging scanners. These and other factors are combining to yield high acoustic sound pressure levels (SPLs) in and around magnetic resonance imagers. Studies have already been conducted which partially characterize this sound field, and various methods have been investigated to attenuate the noise generated. In order to predict the vibration and acoustic response of a gradient coil inside a scanner, finite element analysis (FEA) was carried out. The model was based on specific internal and external structural dimensions and the material physical properties of a gradient coil. The FEA results were verified through experimental modal testing of the same gradient coil. It was found that the experimental modal analysis results were in good agreement with the FEA results. The Lorentz force distribution on the gradient coil caused by the time varying current in the coil windings was then applied to the FEA model to obtain the velocity distribution of the coil surface as a function of time. A vibro-acoustic computational model was then developed based on the verified FEA model. The surface velocity distribution was then used to predict the sound field inside the gradient coil. The vibro-acoustic model was verified using experimental noise measurements with swept sinusoidal waveform inputs to the gradient coil conductors. The numerical methods developed in this study could provide a guide and virtual testing platform for the designer of gradient coils to predict the vibration and acoustic behavior of new designs and thereby offer the opportunity to redesign and/or optimize the design to reduce SPLs.
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Yamamoto, Takahiko, and Kohji Koshiji. "Magnetic-Field Immunity Examination and Evaluation of Transcutaneous Energy-Transmission System for a Totally Implantable Artificial Heart." Advances in Power Electronics 2012 (January 9, 2012): 1–5. http://dx.doi.org/10.1155/2012/421639.
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Transcutaneous energy transmission (TET) is the most promising noninvasive method for supplying driving energy to a totally implantable artificial heart. Induction-heating (IH) cookers generate a magnetic flux, and if a cooker is operated near a transcutaneous transformer, the magnetic flux generated will link with its external and internal coils. This will affect the performance of the TET and the artificial heart system. In this paper, we present the design and development of a coil to be used for a magnetic immunity test, and we detail the investigation of the magnetic immunity of a transcutaneous transformer. The experimental coil, with five turns like a solenoid, was able to generate a uniform magnetic field in the necessary bandwidth. A magnetic-field immunity examination of the TET system was performed using this coil, and the system was confirmed to have sufficient immunity to the magnetic field generated as a result of the conventional operation of induction-heating cooker.
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Sun, Susan Y., Danny A. Mammo, Dara D. Koozekanani, and Sandra R. Montezuma. "Hemifacial Spasm in an Argus II Retinal Prosthesis Patient." Journal of VitreoRetinal Diseases 4, no. 4 (2019): 325–26. http://dx.doi.org/10.1177/2474126419890497.
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Purpose: A 59-year-old man with retinitis pigmentosa, who received an Argus II retinal prosthesis in the left eye 3 years prior, presented with left-sided involuntary facial contractions that occurred only after turning on the Argus II device. Methods: A case report. Results: Given that this patient's reported and visualized lower eyelid twitching corresponds to the location of the external region of the implanted coil, we hypothesize that heat or wirelessly transmitted electrical signals from the external coil to the implanted coil may induce spasm of the facial nerve and thus play a role in hemifacial spasm onset. Conclusions: To our knowledge, this is the first report of hemifacial spasm associated with Argus II use.
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Tang, Fei, Zi Lin Yan, and Xiao Hao Wang. "Experimental Research on Lift up and Drag Reduction Effect of Streamwise Travelling Wave Wall." Key Engineering Materials 483 (June 2011): 721–26. http://dx.doi.org/10.4028/www.scientific.net/kem.483.721.
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Travelling wave wall used for Micro Air Vehicle flow control is studied to find out its drag reduction effect. Aerodynamic characteristics of the airfoil with and without a streamwise travelling wave on its surface are calculated. The interrelationship is also analyzed among lift, drag and ratio of motion phase speed to the external flow velocity. The flexible airfoil that can generate streamwise travelling waves is realized via electromagnetic coil actuation. Thirty-six coils are placed streamwisely under heat shrink film and magnets producing magnetic field are placed under coils. Every single coil is controlled by current to move vertically in harmonic motion with 30 degrees phase difference between adjacent ones. So heat shrink film is actuated, and streamwise travelling wave is generated. Meanwhile, a prototype is designed and tested in wind tunnel. The experimental aerodynamic data proves that streamwise traveling wave airfoil can increase lift and reduce air drag.
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Kulik, Marcin, Mariusz Jagieła, and Bernard Baron. "Optimisation of additional coils of a vibration energy harvester using interior point algorithm." ITM Web of Conferences 19 (2018): 01003. http://dx.doi.org/10.1051/itmconf/20181901003.
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The paper aims at applying the interior point algorithm in optimisation of additional coils of a small resonant electromagnetic vibration energy harvester. The system, which consists of a coreless microgenerator is driven by external vibration through a cantilever-beam spring element. Originally, the system contains only one coil mounted centrally between the moving magnets. It was found that the very low induced voltage can be significantly increased by exploitation of leakage flux outside the magnets using additional coils, whose are optimised for maximum voltage.
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Kim, Young Cheol, Hyun Deok Kim, Byoung-Ju Yun, and Sheikh Faisal Ahmad. "A Simple Analytical Solution for the Designing of the Birdcage RF Coil Used in NMR Imaging Applications." Applied Sciences 10, no. 7 (2020): 2242. http://dx.doi.org/10.3390/app10072242.
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A novel analytical solution for the designing of the birdcage RF coil has been demonstrated in this paper. A new concept of dominant resonance path has been introduced in this paper which is used to identify the specific closed current loop in the birdcage RF coil which is responsible for the dominant resonance frequency mode. This concept is used to determine the precise numerical values of the lumped capacitance deployed in the legs and/or end-rings of the birdcage RF coil for its proper operation at the desired resonance frequency. The analytical solution presented in this paper has been established by performing the two-port network based equivalent circuit modeling of the birdcage RF coil. The proposed analytical solution uses T-matrix theory and develops a relationship between the input impedance of the birdcage coil and the impedances of its leg and end-ring segments. The proposed analytical solution provides the information about the resonance frequency spectrum of the birdcage RF coil and solves the issue of its interfacing with external circuits without affecting its resonance characteristics. Based upon the proposed analysis and designing strategy presented in this paper, the low pass, high pass and band pass configurations of the birdcage RF coil were successfully implemented with FPCB (Flexible Printed Circuit board) technique for small volume NMR imaging applications at 1.5 T and 3.0 T MRI system. The results obtained for the implemented birdcage coils using the proposed analysis and designing technique are in closed agreement with already established methods.
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Franek, Jaroslav. "On Induction Heating - Conductor Excited by External Field." Journal of Electrical Engineering 64, no. 4 (2013): 261–64. http://dx.doi.org/10.2478/jee-2013-0038.
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Electromagnetic field in a banded strip conductor excited by external AC voltage driven coil is analyzed. Inhomogeneous wave equation describing this axis-symmetrical configuration is deduced and solved to find the induced current density and the directional energy flux density (Poynting vector) in the conductor.
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Ahmedov, Haci, Beste Korutlu, Lev Dorosinskiy, Recep Orhan, and Ozlen Tuncel. "External Magnetic Field Measurements in UME Kibble Balance." ACTA IMEKO 9, no. 3 (2020): 33. http://dx.doi.org/10.21014/acta_imeko.v9i3.780.
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The new definition of kilogram in terms of the fixed value of Planck constant ensures the long-term stability of SI mass unit and enables traceability from more than one source. Kibble balance experiments offer an effective primary realization method for the new definition of kilogram. Kibble Balance apparatus operating at National Metrology Institute of Turkey is designed with a stationary coil and an oscillating magnet. In contradistinction to traditional moving coil Kibble balance experiments, external magnetic field brings an asymmetry between the Ampere’s law of force and the Faraday’s law of induction in moving magnet experiments. In this paper, we develop a method based on the external magnetic flux density difference measurements in vertical direction to take into account the effect of the external magnetic field on the realization of kilogram. The proposed model in this approach fits well with the data such that the kilogram realization requirement is met within the accuracy of the measuring instrument.
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Novak, Dmytro, and Sergey Osaulenko. "Development and analysis of filament holder for fused filament fabrication 3D printer using Python programming language." Technologies and Engineering 26, no. 1 (2025): 11–22. https://doi.org/10.30857/2786-5371.2025.1.1.
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The work aimed to analyse and develop a 3D printer coil holder using the Python programming language. The methodology included a coil holder designed using computer-aided design (CAD) software, namely Autodesk Fusion 360. External libraries and plug-ins such as Stress Analysis and Generative Design were used for optimisation. The suitability of the developed design for improving the feeding of strings and reducing their tangling when printing on a 3D printer was determined. The operation of the coil holder with different types and coil sizes was analysed. The developed spool holder successfully passed 97% of the tests for printing models using PLA, ABS and PETG. Testing the measurements of the coil holder with a PROTESTER WDF-30 digital dynamometer revealed several essential observations: Teflon tubing added additional friction, increasing both the minimum and maximum forces by approximately 0.2 N, and slightly reducing the range between the minimum and maximum values; plastic coils showed lower minimum forces, ~ 0.4 N, due to reduced friction, but a more extensive range, ~ 0.5 N, due to their greater mass, and cardboard coils had higher minimum forces, ~ 0.5 N, but a smaller range, ~ 0.3 N; no tension significantly reduced both minimum, ~ 0.2 N, and maximum, ~ 0.3 N, forces, as well as the range between them, ~ 0.1 N, and this condition increased the risk of coil entanglement; the effect of the Teflon tube was more pronounced under proper tension conditions, approximately 0.2-0.3 N; the high-tension setup showed significantly higher minimum, ~ 0.8 N, and maximum, ~ 1.1 N, forces compared to the developed holder (minimum ~ 0.5 N, maximum ~ 0.8 N), but the range of acceptable values was similar, the increased minimum force in the high-tension setup could potentially lead to insufficient extrusion and increased extruder wear. The developed coil holder reduces the printer’s extruder mechanism load by maintaining an optimal tension in the range of 0.5 to 0.8 N. This can significantly extend the life of critical components, reducing the cost of maintaining the 3D printer
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McGee, Kiaran P., Norbert G. Campeau, Robert J. Witte, et al. "Evaluation of a New, Highly Flexible Radiofrequency Coil for MR Simulation of Patients Undergoing External Beam Radiation Therapy." Journal of Clinical Medicine 11, no. 20 (2022): 5984. http://dx.doi.org/10.3390/jcm11205984.
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Purpose: To evaluate the performance of a new, highly flexible radiofrequency (RF) coil system for imaging patients undergoing MR simulation. Methods: Volumetric phantom and in vivo images were acquired with a commercially available and prototype RF coil set. Phantom evaluation was performed using a silicone-filled humanoid phantom of the head and shoulders. In vivo assessment was performed in five healthy and six patient subjects. Phantom data included T1-weighted volumetric imaging, while in vivo acquisitions included both T1- and T2-weighted volumetric imaging. Signal to noise ratio (SNR) and uniformity metrics were calculated in the phantom data, while SNR values were calculated in vivo. Statistical significance was tested by means of a non-parametric analysis of variance test. Results: At a threshold of p = 0.05, differences in measured SNR distributions within the entire phantom volume were statistically different in two of the three paired coil set comparisons. Differences in per slice average SNR between the two coil sets were all statistically significant, as well as differences in per slice image uniformity. For patients, SNRs within the entire imaging volume were statistically significantly different in four of the nine comparisons and seven of the nine comparisons performed on the per slice average SNR values. For healthy subjects, SNRs within the entire imaging volume were statistically significantly different in seven of the nine comparisons and eight of the nine comparisons when per slice average SNR was tested. Conclusions: Phantom and in vivo results demonstrate that image quality obtained from the novel flexible RF coil set was similar or improved over the conventional coil system. The results also demonstrate that image quality is impacted by the specific coil configurations used for imaging and should be matched appropriately to the anatomic site imaged to ensure optimal and reproducible image quality.
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Wang, Yue, Jin Xie, Fengtian Zhang, Fenggang Tao, Zhuang Xiong, and Chao Zhi. "A bi-stable mechanism actuated by patterned permanent magnet and Cu-Ni integrated micro-coil." Journal of Micromechanics and Microengineering 32, no. 3 (2022): 035005. http://dx.doi.org/10.1088/1361-6439/ac5170.
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Abstract This paper presents a bi-stable mechanism, which mainly consists of a suspended mass, a spacer and a bottom plate. Electromagnetic actuation is used for switching between two states (i.e. ‘On/Off’ state). The actuation is achieved via permanent magnet (PM) on the suspended mass and micro-coils embedded in the bottom plate. Different from spiral coil and central core in conventional design, micro-coils in this paper integrate Cu and Ni together as a whole, acting as both coil and ferromagnetic core. This integration simplifies the fabrication into one-mask process. Furthermore, chessboard patterned PM is utilized with Cu-Ni integrated micro-coils to generate enhanced force density. The bi-stable mechanism is designed, fabricated and experimentally characterized. Total size of this mechanism is 16 × 14 × 2 mm3. No power is needed for holding either of the state. Switching processes (both ‘On’ to ‘Off’ and ‘Off’ to ‘On’) can be realized with external acceleration of 24 G (gravity) and 37 G, respectively. Furthermore, resetting (i.e. ‘On’ to ‘Off’) can also be accomplished with 1.5 A current input.
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Wang, Zhenpo, Lantian Li, Junjun Deng, Baokun Zhang, and Shuo Wang. "Magnetic Coupler Robust Optimization Design for Electric Vehicle Wireless Charger Based on Improved Simulated Annealing Algorithm." Automotive Innovation 5, no. 1 (2022): 29–42. http://dx.doi.org/10.1007/s42154-021-00167-9.
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AbstractFleets of autonomous vehicles including shuttle buses, freight trucks, and road sweepers will be deployed in the Olympic Village during Beijing 2022 Winter Olympics. This requires intelligent charging infrastructure based on wireless power transfer technology to be equipped. To increase the misalignment tolerance of a high-power wireless charger, the robustness of the magnetic coupler should be optimized. This paper presents a new type of unipolar coupler, which is composed of three connected coils in series. The dimensional configuration of the coils is analyzed by the finite element method. The characteristic parameters of the coil are identified with their influence on the self-inductance and coupling coefficient. An expert model is built, whose feasibility can be verified in the aimed design domain. Combined with the expert model, an improved simulated annealing algorithm with a backtracking mechanism is proposed. The primary coil can reach the expected characteristics from any starting parameter combination through the proposed optimization algorithm. Under the same conditions in terms of external circuit parameters, ferrite usage, and aluminum shielding, the offset sensitivity of the magnetic coupler can be reduced from 58.79% to 18.89%. A prototype is established, validating the feasibility of the proposed coil structure with the optimized parameter algorithm.