Coil Device Research Articles

A low‐complexity scheme for enlarging the dynamic range of the open‐loop I‐FOG

ABSTRACTBoth the dynamic range and the sensitivity are very important parameters of the interferometric fiber‐optic gyroscopes (I‐FOGs), and generally the large dynamic range and the high sensitivity are contradictory in the open‐loop I‐FOGs. In this article, an efficient and easy to be implemented signal processing scheme is proposed for enlarging the dynamic range of the open‐loop I‐FOGs without reducing the sensitivity. A prototype was developed to verify the feasibility of the new scheme and compare its performance with the conventional open‐loop I‐FOGs. Experimental results show that, compared with the conventional open‐loop I‐FOG with the same fiber coil and optical devices, the dynamic range of the open‐loop I‐FOG with the aid of the new signal processing scheme is enlarged to ±360 (°/s) exceeding the single value area ±63 (°/s) of the conventional open‐loop I‐FOG obviously and the bias drift reduces from 0.068°/h to 0.046°/h. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:498–502, 2016

Defect-Free Carbon Nanotube Coils.

Carbon nanotubes are promising building blocks for various nanoelectronic components. A highly desirable geometry for such applications is a coil. However, coiled nanotube structures reported so far were inherently defective or had no free ends accessible for contacting. Here we demonstrate the spontaneous self-coiling of single-wall carbon nanotubes into defect-free coils of up to more than 70 turns with identical diameter and chirality, and free ends. We characterize the structure, formation mechanism, and electrical properties of these coils by different microscopies, molecular dynamics simulations, Raman spectroscopy, and electrical and magnetic measurements. The coils are highly conductive, as expected for defect-free carbon nanotubes, but adjacent nanotube segments in the coil are more highly coupled than in regular bundles of single-wall carbon nanotubes, owing to their perfect crystal momentum matching, which enables tunneling between the turns. Although this behavior does not yet enable the performance of these nanotube coils as inductive devices, it does point a clear path for their realization. Hence, this study represents a major step toward the production of many different nanotube coil devices, including inductors, electromagnets, transformers, and dynamos.

Faster, more accurate, parallelized inversion for shape optimization in electroheat problems on a graphics processing unit (GPU) with the real-coded genetic algorithm

Purpose – Inverting electroheat problems involves synthesizing the electromagnetic arrangement of coils and geometries to realize a desired heat distribution. To this end two finite element problems need to be solved, first for the magnetic fields and the joule heat that the associated eddy currents generate and then, based on these heat sources, the second problem for heat distribution. This two-part problem needs to be iterated on to obtain the desired thermal distribution by optimization. Being a time consuming process, the purpose of this paper is to parallelize the process using the graphics processing unit (GPU) and the real-coded genetic algorithm, each for both speed and accuracy. Design/methodology/approach – This coupled problem represents a heavy computational load with long wait-times for results. The GPU has recently been demonstrated to enhance the efficiency and accuracy of the finite element computations and cut down solution times. It has also been used to speedup the naturally parallel genetic algorithm. The authors use the GPU to perform coupled electroheat finite element optimization by the genetic algorithm to achieve computational efficiencies far better than those reported for a single finite element problem. In the genetic algorithm, coding objective functions in real numbers rather than binary arithmetic gives added speed and accuracy. Findings – The feasibility of the method proposed to reduce computational time and increase accuracy is established through the simple problem of shaping a current carrying conductor so as to yield a constant temperature along a line. The authors obtained a speedup (CPU time to GPU time ratio) saturating to about 28 at a population size of 500 because of increasing communications between threads. But this far better than what is possible on a workstation. Research limitations/implications – By using the intrinsically parallel genetic algorithm on a GPU, large complex coupled problems may be solved very quickly. The method demonstrated here without accounting for radiation and convection, may be trivially extended to more completely modeled electroheat systems. Since the primary purpose here is to establish methodology and feasibility, the thermal problem is simplified by neglecting convection and radiation. While that introduces some error, the computational procedure is still validated. Practical implications – The methodology established has direct applications in electrical machine design, metallurgical mixing processes, and hyperthermia treatment in oncology. In these three practical application areas, the authors need to compute the exciting coil (or antenna) arrangement (current magnitude and phase) and device geometry that would accomplish a desired heat distribution to achieve mixing, reduce machine heat or burn cancerous tissue. This process presented does it more accurately and speedily. Social implications – Particularly the above-mentioned application in oncology will alleviate human suffering through use in hyperthermia treatment planning in cancer treatment. The method presented provides scope for new commercial software development and employment. Originality/value – Previous finite element shape optimization of coupled electroheat problems by this group used gradient methods whose difficulties are explained. Others have used analytical and circuit models in place of finite elements. This paper applies the massive parallelization possible with GPUs to the inherently parallel genetic algorithm, and extends it from single field system problems to coupled problems, and thereby realizes practicable solution times for such a computationally complex problem. Further, by using GPU computations rather than CPU, accuracy is enhanced. And then by using real number rather than binary coding for object functions, further accuracy and speed gains are realized.

Controllable deposition of ZnO-doped SnO2 nanowires on Au/graphene and their application in cataluminescence sensing for alcohols and ketones

In the present work, we developed a miniaturized tungsten coil device, a cataluminescence gas detector for alcohols and ketones using zinc oxide-doped tin dioxide (SnO2:ZnO) nanowires as the sensing materials. SnO2:ZnO nanowires were controllably deposited on tungsten coil which was coated with Au/reduced graphene oxide composites via an atmospheric pressure chemical vapor deposition process. This SnO2:ZnO nanowires-based gas sensor has fast and sensitive response to alcohols and ketones with a wide range. The response time and recovery time of the present sensor for ethanol were 7s and 40s, respectively. The linear range of ethanol was 11.7–204.7μgmL−1 with a detection limit of 11.0μgmL−1 (S/N=3). In addition, it has relatively good reproducibility, and its linear response to alcohols and ketones makes it to be promising in practical application.

Design of a Magnetic Gradient Coil with High Uniformity

Maxwell coil cannot meet the magnetic sensor calibration when the high uniformity of magnetic gradient is required and the space size is strictly limited. To solve this problem, a magnetic gradient coil with high uniformity was designed as magnetic sensor calibration device. Application of internal series method analyzed the magnetic field that a single axial symmetric coil generated, and then got the general characteristics of the magnetic gradient field distribution. On this basis, the structural parameters and the uniformity of magnetic gradient coil with high uniformity were calculated. Simulation analyses were carried out on the coil model and complete the design and production of magnetic gradient coil device. Finally, the data obtained from actual measurement and simulation proves the correctness of the design.

Transcatheter Closure of Perimembranous Ventricular Septal Defects using Nit-Occlud® Lê VSD Coil: Early and Mid-Term Results

Our objective was to investigate the short- and mid-term results of transcatheter ventricular septal defect (VSD) closure with the Nit-Occlud(®) Lê VSD coil. Retrospective data collection study. Data were collected from 20 patients who underwent transcatheter VSD closure with the Nit-Occlud(®) Lê VSD coil device between October 2011 and June 2013. The mean age of the study subjects was 7.3 ± 4.0 years, and the mean weight was 25.7 ± 11.8 kg. The distance between the defect and the aortic valve, measured using angiography, was an average of 5.1 ± 2.0 mm, and the left ventricular opening averaged 8.2 ± 2.1 mm. The mean value of the Q p/Q s ratio was 1.7 ± 0.4. Intravascular hemolysis developed in the first few hours after the procedure in three patients. In one of these cases, despite medical treatment and the implantation of a detachable coil placed into the Nit-Occlud(®) device transcatheterly, hemolysis persisted. This device was removed and the VSD was closed surgically. In the other two cases, although the residual shunt persisted on echocardiography, the hemolysis regressed spontaneously. There were no rhythm problems or other complications during the follow-up period of 12.3 ± 6.6 months. In the selected cases, for the transcatheter treatment of VSD, the Nit-Occlud(®) Lê VSD coil device can be used. When compared with other VSD closure devices, there was no development of a permanent atrioventricular block, which is an important advantage. However, patients with a residual shunt should be monitored closely for the development of hemolysis during the first few hours.

All-digital signal-processing open-loop fiber-optic gyroscope with enlarged dynamic range

We propose and realize a new open-loop fiber-optic gyroscope (FOG) with an all-digital signal-processing (DSP) system where an all-digital phase-locked loop is employed for digital demodulation to eliminate the variation of the source intensity and suppress the bias drift. A Sagnac phase-shift tracking method is proposed to enlarge the dynamic range, and, with its aid, a new open-loop FOG, which can achieve a large dynamic range and high sensitivity at the same time, is realized. The experimental results show that compared with the conventional open-loop FOG with the same fiber coil and optical devices, the proposed FOG reduces the bias instability from 0.259 to 0.018 deg/h, and the angle random walk from 0.031 to 0.006 deg/h(1/2), moreover, enlarges the dynamic range to ±360 deg/s, exceeding the maximum dynamic range ±63 deg/s of the conventional open-loop FOG.

Assessing the stability of rolling

By plotting histograms and calculating the variation coefficient of the primary drive’s torque in the cells of a continuous rolling mill, the stability of the process may be assessed. The elastic torques and motor torques in cells 5–7 of the 1680 mill in strip rolling were measured simultaneously at OAO Zaporozhstal’, and the results were statistically analyzed. The motor’s electromagnetic torque reflects the frequency properties of the transient process in the mechanical system of the drive and the reaction to technological perturbations, such as variation in strip temperature. By superposition of the motor’s torque histograms and calculation of the torque’s variation coefficient, the stability of rolling in the cells of a continuous mill may be qualitatively and quantitatively estimated. Numerical estimates of the rolling stability are presented for strip batches with and without intermediate coiling devices.

O-017 Preliminary Experience with a New Barrel Shaped Bifurcation Aneurysm Bridging Device

PurposeTo test the feasibility of a novel fully retrievable barrel-shaped vascular reconstruction device for stent assisted endovascular treatment of wide-necked bifurcation aneurysms.Methods16 Canine were utilised to assess the acute technical...

Long-Term Bilayer Encapsulation Performance of Atomic Layer Deposited Al<formula formulatype="inline"> <tex Notation="TeX">$_{\bf 2}$</tex></formula>O<formula formulatype="inline"><tex Notation="TeX">$_{\bf 3}$</tex></formula> and Parylene C for Biomedical Implantable Devices

We present an encapsulation scheme that combines atomic layer deposited (ALD) Al₂O₃ and Parylene C for the encapsulation of implantable devices. The encapsulation performances of combining alumina and Parylene C was compared to individual layers of Parylene C or alumina and the bilayer coating had superior encapsulation properties. The alumina-Parylene coated interdigitated electrodes (IDEs) soaked in PBS for up to nine months at temperatures from 37 to 80 °C for accelerated lifetime testing. For 52-nm alumina and 6-μm Parylene C, leakage current was ∼20 pA at 5 VDC, and the impedance was about 3.5 MΩ at 1 kHz with a phase near -87° from electrochemical impedance spectroscopy for samples soaked at 67 °C for equivalent lifetime of 72 months at 37 °C. The change of impedance during the whole soaking period (up to 70 months of equivalent soaking time at 37 °C) over 1 to 10⁶ Hz was within 5%. The stability of impedance indicated almost no degradation of the encapsulation. Bias voltage effect was studied by continuously applying 5 VDC, and it reduced the lifetime of Parylene coating by ∼75% while it showed no measurable effect on the bilayer coating. Lifetime of encapsulation of IDEs with topography generated by attaching a coil and surface mount device (SMD) capacitor was about half of that of planer IDEs. The stable long-term insulation impedance, low leakage current, and better lifetime under bias voltage and topography made this double-layer encapsulation very promising for chronic implantable devices.

Le modafinil améliore les performances de conduite simulée des malades souffrant d’hypersomnie : étude randomisée placebo-verum

To report a novel technique for temporary and permanent vessel occlusion with a single microcatheter and investigate its efficacy in endovascular management of cerebral aneurysms and invasive head and neck tumors.A 58-year-old woman with a history of T3N0 squamous cell carcinoma of the tongue with extensive surgical resections and radiotherapy presented to the emergency department with further wound dehiscence and exposure of the left cervical internal carotid artery (ICA). Digital subtraction angiography (DSA) was performed with the patient under conscious sedation. An Ascent balloon, 4 mm × 15 mm, was prepared and introduced into the proximal ICA. While the patient was fully awake, temporary balloon occlusion (TBO) was performed for 30 minutes. The Ascent balloon was kept inflated. Through the inflated Ascent balloon, coil embolization of the proximal ICA was initiated. The interstices of the coils were filled with Onyx 18 and Onyx 34 liquid embolic agents (ev3 Neurovascular, Inc, Irvine, California, USA).The Ascent balloon can be used as a temporary balloon device and as a coil or Onyx embolization device. As a result, fewer catheters, guidewires, and balloon inflations and deflations are required for the procedure, which is both cost-effective and time-efficient. The combination of initial coiling to create a framework for the deconstruction with a liquid embolic agent (Onyx) is a safe and efficient technique for vessel deconstruction. Flow arrest with proximal balloon occlusion minimizes the risks of distal thromboembolic events during embolization.This novel technique for temporary and permanent vessel occlusion with a single microcatheter is both cost-effective and time-efficient.

The Relevance of Microsurgical Management of Non-Basilar Posterior Circulation Aneurysm in the Current Era of Endovascular Management

Introduction: Non-basilar posterior circulation aneurysms are a small subset of aneurysms that still pose a considerable challenge to the neuro-interventionist for endovascular management. They are often wide neck, and in most cases the vessels take their origin from the neck of the aneurysm. The better results of stent-assisted coiling and pipeline embolization devices (PEDs) could not be translated to this subset of aneurysms, because the parent vessel’s size is less than 2 mm and even the latest stents require a larger diameter. The endovascular options in this subset of aneurysms are limited, especially in wide-neck configuration or where the main branch incorporates into the neck of the aneurysm. We report on our experience with consecutively operated-on non-basilar posterior circulation aneurysms, to present the role of microneurosurgery as a realistic management option for these difficult aneurysms.

脳動脈瘤コイル塞栓術後CT Angiographyにおける単色X線等価画像を用いたエネルギーサブトラクション処理の基礎的検討

Coil-embolized cerebral aneurysms are difficult to evaluate using computed tomography (CT) angiography (CTA) due to artifacts caused by the coil devices. This study was conducted to assess the practicality of energy subtraction processing using monochromatic images obtained using CTA after coil embolization of a cerebral aneurysm. In this study, the changes in the CT value of the contrast agent and the coil were analyzed not only at varying monochromatic energy levels but also by energy subtraction processing. Our analyses revealed an exponential change in the CT value of the contrast agent at any desired energy. We also found that the CT value of the coil was unchanged at the upper threshold of the grayscale limit. Based on these results, we were able to create images of changes in material-specific CT values and thus eliminate the material. Energy subtraction processing enabled us to distinguish between the contrast agent, the coil, and the artifacts from coil devices. We suggest that energy subtraction processing using monochromatic images can resolve the limitations of CTA after coil embolization of cerebral aneurysms.

Research on Capacitance Current Treatment Methods in Mine High-Voltage Power Grid

In view of the coal mine neutral point ungrounded system when single-phase ground fault occurs, the grounding capacitance current is too big affect the security of coal mine powe supply.The paper analyzed testing data of capacitance current of coal mine network, established a treating scheme of capacitance current according to evaluating results, namely automatic tracking compensation arc suppression coil devices. The running results show that the scheme limits the size of the ground current and decreases rate of accidents of arc grounding over-voltage, which is good for improving the power supply safety.

Cost-Effectiveness of Anti-Retropulsion Devices for Ureteroscopic Lithotripsy

We evaluated the cost-effectiveness of anti-retropulsion devices used during ureteroscopic lithotripsy. A decision analysis model was constructed to compare the cost-effectiveness of ureteroscopic lithotripsy with vs without an anti-retropulsion device. The risk of stone retropulsion was determined from published data in the English language literature. Expected value calculations were used to determine whether the additional cost of a device would be cost-effective to prevent secondary procedures used to treat retropulsed stones. Device cost was determined using the average cost of all commercially available devices. It became cost-effective to use an anti-retropulsion device at or above a 6.3% retropulsion rate. The weighted probability of retropulsion with vs without an anti-retropulsion device was 98.1% vs 83.7%. The estimated costs of secondary procedures needed to treat retropulsed stones were $5,290 for shock wave lithotripsy and $6,390 for ureteroscopy. Average device cost was $278. Thus, the average additional cost of ureteroscopic lithotripsy with vs without an anti-migration device would be $384 vs $952. It is cost-effective to use an anti-retropulsion device at a retropulsion rate of greater than 6.3%.

Radiofrequency Coil for the Creation of Large Ablations: Ex Vivo and In Vivo Testing

PurposeVarious radiofrequency (RF) ablation electrode designs have been developed to increase ablation volume. Multiple heating cycles and electrode positions are often required, thereby increasing treatment time. The objective of this study was to evaluate the performance of a high-frequency monopolar induction coil designed to produce large thermal lesions (>3cm) with a single electrode insertion in a treatment time of less than 10minutes. Materials and MethodsA monopolar nitinol interstitial coil operated at 27.12MHz and 200W was evaluated. Ex vivo performance was tested in excised bovine liver (n=22). In vivo testing (n=10) was conducted in livers of seven Yorkshire pigs. Visual inspection, contrast-enhanced computed tomography (CT), and pathologic evaluation of ablation zones were performed. ResultsAverage ablation volumes in ex vivo and in vivo tests were 60.5cm3±14.1 (5.9×4.4×4.4cm) and 57.1cm3±13.8 (6.1×4.5×4.1cm), with average treatment times of 9.0minutes±3.0 and 8.4minutes±2.7, respectively. Contrast-enhanced CT ablation volume measurements corresponded with findings of gross inspection. Pathologic analysis showed morphologic and enzymatic changes suggestive of tissue death within the ablation zones. ConclusionsThe RF ablation coil device successfully produced large, uniform ablation volumes in ex vivo and in vivo settings in treatment times of less than 10minutes. Ex vivo and in vivo lesion sizes were not significantly different (P=.53), suggesting that the heating efficiency of this higher-frequency coil device may help to minimize the heat-sink effect of perfusion.

Fusion Nuclear Science Facility-AT: A Material and Component Testing Device

A fusion nuclear science facility (FNSF) is a necessary complement to ITER, especially in the area of material and component testing needed for DEMO design development. FNSF-AT, which takes advantage of advanced tokamak (AT) physics, should have neutron wall loading of 1-2 MW/m2, continuous operation for periods of up to 2 weeks, a duty factor goal of 0.3 per year, and an accumulated fluence of 3-6 MW-yr/m2 (~30-60 dpa) in 10 years to enable the qualification of structural, blanket, and functional materials, components, and corresponding ancillary equipment necessary for the design and licensing of a DEMO. Base blankets with a ferritic steel structure and selected tritium blanket materials will be tested and used for the demonstration of tritium sufficiency. Additional test ports at the outboard midplane will be reserved for test blankets with advanced designs or exotic materials and electricity production for integrated high-fluence testing in a DT fusion spectrum. FNSF-AT will be designed using conservative implementations of all elements of AT physics to produce 150-300 MW of fusion power with modest energy gain (Q < 7) in a modest-sized normal conducting coil device. It will demonstrate and help to select the DEMO plasma-facing, structural, tritium-breeding, and functional materials and ancillary equipment including diagnostics. It will also demonstrate the necessary tritium fuel cycle, design and cooling of the first wall chamber, and divertor components. It will contribute to the knowledge on material qualification, licensing, operational safety, and remote maintenance necessary for DEMO design.

Low-profile visible intraluminal support device: immediate outcome of the first three US cases

IntroductionDissecting and wide-necked aneurysms that incorporate a large portion of the parent artery can be challenging to treat with currently available devices. This study reports three cases treated with a...

무선 전력 전송용 고효율 공진기 설계

본 논문에서는 자기 공명 방식의 무선 전력 전송 시스템에서 효율 향상 방안을 제시하였다. 공진 코일은 헬리컬과 스파이럴 형태가 결합된 구조를 제안하였으며, 소스와 디바이스 코일은 단일 원형 루프 형태로 설계하였다. 측정 결과, 송수전 코일이 120 mm의 거리로 이격되어 있을 때 헬리컬과 스파이럴 구조를 결합한 공진기는 기존의 헬리컬 구조의 공진기보다 효율이 13 % 향상되는 결과를 보였다. 뿐만 아니라, 크기도 기존 공진기에 비해 33 % 소형화할 수 있었다. In this paper, an efficiency improvement method in the wireless power transfer system based on magnetic resonance is proposed. A combined helical-spiral structure is adopted for self-resonant coil and source and device coils are designed using circular loop structure. The proposed resonator utilizing combined helical-spiral structure yields 13 % efficiency improvement over that of an existing helical type resonator when the transmitting and receiving coils are separated by 120 mm. In addition, the size can be reduced by 33 % comparing to the previous resonator.

Fusion Nuclear Science Facility - Advanced Tokamak Option

A Fusion Nuclear Science Facility (FNSF) is necessary to make possible a DEMO of the Advanced Tokamak (AT) type after ITER. One candidate, Fusion Nuclear Science Facility-AT (FNSF-AT), should have neutron wall loading of 1-2 MW/m2, continuous operation for periods of up to two weeks, a duty factor goal of 0.3 on a year and neutron fluence of 3-6 MW-yr/m2 in ten years to enable development of blankets suitable for tritium and electricity production while demonstrating nearly all the critical elements necessary for the qualification and design of a DEMO. FNSF-AT, also called FDF, will be designed using conservative implementations of all elements of AT physics to produce 150-300MW fusion power with modest energy gain (Q<7) in a modest sized normal conducting coil device. It will demonstrate and its results will help in the selection of the DEMO tritium breeding blanket concept. It will demonstrate the tritium fuel cycle, the behavior of candidate plasma facing materials, and the design and cooling of the first wall chamber and divertor components. It will also provide experience in safe operation and remote maintenance necessary for the DEMO design.