Pulsed Induction Research Articles

Study on temperature field in the process of induction heat treatment with current assisted weld double side method

At present, in the process of weld induction heat treatment, the common method is to carry out centralized induction heating in the weld area, which will lead to large radial temperature difference of the weld, poor controllability of temperature distribution and easy to cause the defects of residual stress concentration in the weld area. To solve the above problems, this paper adopts the two-sided method to conduct induction heating on both sides of the weld, and at the same time, the auxiliary pulse current is passed into the weld to improve the quality of the weld. ANSYS finite element software is used to establish a multi-field coupling prediction model of electric-magnetic-thermal structure, and explore the distribution law of the auxiliary pulse current and the temperature field of the weld. Finally, an experimental study of pulsed current assisted two-sided induction heating is carried out. Temperature test and metallographic test were carried out respectively to verify the effectiveness of pulsed current assisted induction heating technology.

Machine learning classification of metallic objects using pulse induction electromagnetic data

This paper presents the classification of metallic objects using total and scattered pulse induction electromagnetic data, with a classification accuracy greater than 90%. Machine learning classification is applied to raw electromagnetic induction (EMI) data without the use of a physics-based model. The EMI method is applied to 8 metallic objects placed at increasing distances from 10–55 mm to the EMI sensing system. The EMI sensing system consists of two RL circuits placed in close proximity. Metallic objects are classified using linear algorithms including a perceptron and multiclass logistic regression, and nonlinear algorithms including a neural network, a 1D and 2D convolutional neural network (CNN). EMI data was collected using an experiment in an electromagnetically shielded laboratory. Feature maps are presented that explain the salient components of the EMI data used by the 1D and 2D CNN.

Overview of the Lost Meteorites of Antarctica field campaigns

AbstractThe Lost Meteorites of Antarctica project was the first UK‐led Antarctic meteorite recovery expedition. The project has successfully confirmed two new high‐density meteorite stranding zones in the Hutichison Icefield and Outer Recovery Icefields areas and investigated the geology of three previously unvisited Antarctic nunataks (Turner Nunatak, Pillinger Nunatak, Halliday Nunatak). The project undertook meteorite searching on the ice surface via skidoo reconnaissance and systematic searching and developed a novel pulse induction metal detection system to search for englacial iron‐rich meteorites trapped within the upper one meter of ice. In total, 121 meteorites have been recovered from the ice surface searching activities, which are now curated in the United Kingdom at the Natural History Museum London and are available for scientific analysis.

Feasibility of an inductive pedicle screw loosening detection concept using a pulse induction metal detector

Feasibility of an inductive pedicle screw loosening detection concept using a pulse induction metal detector

High thermal conductivity composite h-BN/EP obtained by pulsed square-wave electric field induction

Electric fields are effective in inducing the orientation of highly thermally conductive fillers in polymers to improve the thermal conductivity of composites. However, the study of the effect of pulsed square wave electric field on thermal conductivity of composites is relatively rare. In this paper, the effect of electric field strength, frequency, and application time of pulsed square-wave electric field on the thermal conductivity of composites is investigated by utilizing the pulsed square-wave electric field to induce the orientation arrangement of h-BN in epoxy resin (EP). The results show that the thermal conductivity of the composites increases with the increase of the electric field strength and the decrease of the frequency, and does not change significantly with the application time. The highest thermal conductivity of 0.453 W/(m·K), which is 3.24 times higher than that of the epoxy resin, was obtained for the composites by applying a pulsed square-wave electric field of 200 V/mm at 0.001 Hz for 1 h with 10 wt% load. It is 1.94 times higher than that of the sample without electric field induction at the same load. This paper also establishes a mathematical relationship between the degree of orientation of h-BN and the thermal conductivity of the composite material, which expands the scope of application of the thermal conductivity model and increases the accuracy of the model calculation. The method is simple in process and suitable for a wide range of high thermal conductivity composite applications with great potential for development.

Electromechanical and thermophysical processes in the pulse induction accelerator of plasma formation

Introduction. Work on the creation and throwing of plasma formations is carried out in the world's leading scientific centers in various ways. The creation of a plasma formation with duration of several milliseconds and its acceleration in an open atmospheric environment to a distance of 0.5-0.6 m was achieved. To create plasma, the energy of the primary discharge circuit is used, followed by the acceleration of the gas-plasma formation with the help of the energy of the secondary circuit. Plasma formation is also obtained due to the electric explosion of a conductor in a rapidly decreasing strong magnetic field, etc. The purpose of the article is a theoretical and experimental study of electromechanical and thermophysical processes in a pulsed induction accelerator, which ensures the creation of plasma formation due to thermal ionization as a result of the electric explosion of the conductor and its throwing in the atmospheric environment relative to the inductor. Method. For the analysis of electromechanical and thermophysical processes in the pulse induction accelerator of plasma formation (IIPP), a mathematical model of the accelerator was developed and implemented in the Сomsol Multiphysics software package, in which the anchor does not change its shape and aggregate state during operation and takes into account the parameters of the accelerator distributed in space. Results. Calculated electromechanical and thermal characteristics of the accelerator. It is shown that the temperature rise in the aluminum foil anchor is significantly uneven. The maximum temperature value occurs in the middle part of the foil closer to the outer edge, and this temperature is significantly higher than the boiling point of aluminum. Scientific novelty. Experimental studies of the IIPP were carried out, in which the armature is made of aluminum and copper foil, and the inductor connected to the high-voltage capacitive energy storage device is made in the form of a flat disk spiral. It was established that during the operation of the IIPP, the armature goes into a plasma state and moves vertically upwards, turning into a three-dimensional lump or a pile of small particles that rose to a considerable height relative to the inductor. Experimentally, the characteristic circular circuit of thermal heating of the copper foil of the anchor, which is fixed on a glass-textolite sheet, is shown, which indicates a similar nature of plasma formation. Practical value. The results of experimental studies with an accuracy of up to 15 % coincide with the calculated ones and show the validity of the IIPP concept, in which, due to the high density of the induced current in the armature, thermal ionization occurs as a result of an electric explosion of the conductor with its transition to the plasma state. And the interaction of the plasma formation with the magnetic field of the inductor leads to the appearance of an electrodynamic force that ensures its movement in the open atmospheric environment.

Rapid Object Depth Estimation From Position-Referenced EMI Data Using Machine Learning

State-of-the-art methods for localization and detection of small metallic objects using electromagnetic induction (EMI) sensing usually struggle due to the strong correlation between the intrinsic parameters of the object and the object’s depth. In this article, we present a machine-learning-based approach for rapid estimation of metallic object depth from line-scan EMI data. The 1-D-convolutional neural network (1D-CNN), trained on a simulated dataset, takes advantage of metal detector (MD) spatial response to extract features from which depth is inferred. Experimental evaluation using a mono-coil pulse induction MD and an electromagnetic (EM) tracking system was performed under laboratory conditions on a large dataset containing arbitrarily oriented objects of different sizes, shapes, and materials. The nonlinear least-squares (NLSs) inversion was employed as the benchmark method for comparison. The proposed solution shows superior performance over NLS at depths >10 cm. From two passes of MD over the object at depths within the range of 2.5–15 cm, our method yields a median absolute error (MedAE) on the order of millimeters.

Therapeutic Plasma Exchange in Certain Immune-Mediated Neurological Disorders: Focus on a Novel Nanomembrane-Based Technology.

Therapeutic plasma exchange (TPE) is an efficient extracorporeal blood purification technique to remove circulating autoantibodies and other pathogenic substances. Its mechanism of action in immune-mediated neurological disorders includes immediate intravascular reduction of autoantibody concentration, pulsed induction of antibody redistribution, and subsequent immunomodulatory changes. Conventional TPE with 1 to 1.5 total plasma volume (TPV) exchange is a well-established treatment in Guillain-Barre Syndrome, Chronic Inflammatory Demyelinating Polyradiculoneuropathy, Neuromyelitis Optica Spectrum Disorder, Myasthenia Gravis and Multiple Sclerosis. There is insufficient evidence for the efficacy of so-called low volume plasma exchange (LVPE) (<1 TPV exchange) implemented either by the conventional or by a novel nanomembrane-based TPE in these neurological conditions, including their impact on conductivity and neuroregenerative recovery. In this narrative review, we focus on the role of nanomembrane-based technology as an alternative LVPE treatment option in these neurological conditions. Nanomembrane-based technology is a promising type of TPE, which seems to share the basic advantages of the conventional one, but probably with fewer adverse effects. It could play a valuable role in patient management by ameliorating neurological symptoms, improving disability, and reducing oxidative stress in a cost-effective way. Further research is needed to identify which patients benefit most from this novel TPE technology.

Metal detecting robotic vehicle

Today’s need for workers in mines is to detect the metals in the path. The previously used metal detector uses BFO (Beat Frequency Oscillation) and RFO (Resonant Frequency Oscillation) techniques which has a drawback of frequency instability. The depth further can be increased by Pulse Induction Method. It uses a single coil as both transmitter and receiver. When current is sent through the coil each pulse generates a magnetic field. When the pulse ends it reflects and it is called the reflected pulse. An electrical spark is generated when both the pulses collapse. Now when a metal comes in the range of the magnetic field, there is a change in the amplitude and phase of the pulse in the received coil. Planar square spiral coil is the geometry best suited for increasing depth sensitivity. It depends on the parameters such as fill ratio and spacing to width ratio. A coil with a higher fill ratio is shown to have higher size sensitivity and a coil with a smaller wire spacing-to-width ratio is shown to have higher depth sensitivity. Using this Pulse Induction Metal Detector we build a robotic vehicle.

МЕТОДИ НЕРУЙНІВНОЇ ДІАГНОСТИКИ РОЗТАШУВАННЯ МЕТАЛЕВОЇ АРМАТУРИ ШТИРОВИХ З’ЄДНАНЬ У ШВАХ ЖОРСТКИХ ДОРОЖНІХ ОДЯГІВ

Introduction. In the world-wide practice on construction of rigid road pavements significant attention has been given to jointed plain concrete pavements (JPCP) with transverse joints strengthened by dowel bars. Performance of JPCP is sufficiently affected by right alignment and location of dowel bars thereby the methods of non-destructive testing of dowel bar positioning have been gain in great importance. This paper represents analytical review of methods of non-destructive testing of dowel bar alignment and location emphasizing an attention on standard method using magnetic pulse induction which is applicable to testing of metallic bar position in concrete pavements. General Part. In the general part of this paper, several main aspects of reviewed test method were analyzed: the classification of dowel bars misalignment and their impact on pavement performance; the comparison of implemented methods of non-destructive testing of dowel bar positioning; possibilities of method of magnetic impulse induction and an approach to analytical evaluation of transverse joints dowel bar misalignment using magnetic image tomography; the usage of results of testing of transverse joints dowel bar position to eliminate dowel bars misalignment; examples of predictive estimation of results of testing of transverse joints dowel bar position and their impact on performance of JPCP. The reviewed method of testing and test results estimation concerns practice on application of two levels of performance (e.g. acceptable level and rejectable level) to evaluate the performance of each individual dowel bar or each doweled transverse joint and also a section of rigid road pavement with several consecutive transverse joints with restricted performance. Conclusions. 1. World-wide implemented standard method of non-destructive testing of dowel bar alignment and location allows to detect and to eliminate dowel bars misalignment thus ensuring required load transfer efficiency and international roughness index of rigid road pavements. The estimation of road pavement sections with several consecutive joints considering each joint performance allows to ensure the designed service life of road pavement. 2. Standard method of non-destructive testing of dowel bar alignment and location for transverse joints of rigid road pavement using magnetic pulse induction developed by American Society for Testing and Materials assures high precision of measurement of metallic bar position in doweled bar of concrete pavement joints and enables to detect five types of dowel bar misalignment. 3. In connection with the intensification of issues on construction of rigid road pavements in Ukraine as well as the high importance of the considering test method, an important task should be the development and implementation of an appropriate national standard.

Design, Fabrication, and Experimental Results of a Pulsed Power-Based Four-Stage Induction Coilgun for Launching a Heavy Projectile

Since 2016, Hanwha Defense Corporation has been working on applying electromagnetic launch technologies such as induction coilguns to cold-launch systems that can launch guided missiles. First, a design procedure of a multistage coilgun system based on the pulsed power driven by capacitor banks was developed using the Taguchi method, and a laboratory-scale three-stage coilgun capable of launching a 21.68-kg projectile at a maximum speed of 27.5 m/s was built and the results of the experiment were announced in 2018. In this article, we design, fabricate, and present the experimental results of a pulsed power-based four-stage induction coilgun using the proposed procedure to prove the validity of the electromagnetic launch technology for heavy missile launch. In this experiment, a 100-kg projectile was fired under 4-kV charging conditions, the maximum speed of the projectile was 25 m/s or more, and an efficiency of 15% was achieved without considering the mass of the armature. In this study, by accelerating a 100-kg projectile to 27 m/s, the feasibility of an electromagnetic launcher developed for heavy missile launch was verified.

Claus Colani’s Pulsed Electromagnetic Induction Principle: Documents and Data of the First Archaeo-Geophysical Prospecting in Bavaria

– Historical retrospective highlighting and honoring the pioneering work in archaeological prospecting made by development engineer Claus Colani. – Colani’s principle of pulsed electromagnetic induction, his publications and biography. – The high efficiency of Colani’s devices and his visionary approach are demonstrated by the unpublished data from the first Bavarian archaeo-geophysical survey carried out at Manching.

A Detection System with Spider Web Coil-Based Wireless Charging and an Active Battery Management System

The article presents a detection system with spider web coil-based wireless charging. Commonly available metal detectors are sold as handheld systems, which enable only progressive, lengthy, time-consuming search. Importantly, a part of the investigated area can thus be easily missed, and the probability that a metal object will not be found increases substantially. This problem, however, is eliminable via the automatic position tracking mode embedded in the solution obtained through our research. The proposed system facilitates using the spider web coil simultaneously for wireless charging and metal detection by pulse induction. The topology of the detector can emit variable pulse lengths, thus allowing the device to detect more types of metal and to adapt itself to the permeability of the soil. The coil has a branch in a relevant part of the winding to reduce undesirable electromagnetic interference during the charging. On the transmitting side of the topology, impedance matching is included to maintain the maximum spatial gap variability. By changing the position of the receiving side, the output voltage changes; therefore, a high efficiency DC/DC converter is employed. The individual battery cells demonstrate different internal resistances, requiring us to apply a new method to balance the cells voltage. The system can be utilized on self-guided vehicles or drones; advantageously, a GPS resending the coordinates to a mesh radio allows for accurate positioning. With the mesh topology, potential cooperation between the multiple systems is possible. The setup utilizes the same coil for wireless power transfer and detection.

Comparative analysis of electromechanical processes in induction-dynamic converter with mobile inductor and two disks

General description of the research topic. The article presents a comprehensive study of traditional induction-dynamic mechanisms (with one disk and a fixed coil) and multi-core induction-dynamic mechanisms (linear pulse induction converters) with a movable coil and two disks. Actuality of the topic. Such induction-dynamic mechanisms are widely used in various fields, in particular, in electrical apparatus industry, where speed is one of the most important characteristics. The purpose of the article is a comparative analysis and refinement of the characteristics of the traditional induction-dynamic system with one disk and a fixed coil and multi-core one with a movable coil and two disks. Research method, scientific novelty. The calculations are based on the solution of the equations of the electromagnetic field and the equations for the electric circuit of the coil. Practical significance and main conclusions. During the calculations, the values of electromagnetic force and force impulse acting on the moving disk, energy losses in the system and electromagnetic energy of the system are determined. The results of the study are presented in the form of graphs, namely, the coil current and total magnetic energy for a traditional induction-dynamic mechanism with one disk and for multi-core one with two disks, Joule losses in a fixed coil and disk (in a traditional system) and in a moving coil and two disks (in a multi-core system), force impulse and electromagnetic force of a moving coil (in a multi-core system) and a moving disk (in a traditional and a multi-core system) total impulse of the moving parts of the induction-dynamic mechanism with a multi-core system, as well as the electromagnetic force and the total force acting on the moving parts of the induction-dynamic mechanism with a multi-core system. It is shown that the induction-dynamic mechanism with two disks is less effective in terms of electromagnetic force, impulse and electromagnetic energy than the induction-dynamic mechanism of the traditional layout.

Arterial stiffness as a risk factor for hypotension during induction of general anesthesia

IntroductionHypotension after induction of general anaesthesia is identified as an independent factor in predicting adverse clinical outcomes. Preoperative evaluation of arterial stiffness could identify patients with an impaired vascular function and an altered haemodynamic response to induction of general anaesthesia. The purpose of this study is to investigate the relationship between arterial stiffness and blood pressure variation during induction of general anaesthesia.Material and methodsThis was an observational study that included patients who underwent surgical procedures under general anaesthesia. We used several systolic arterial pressure and mean arterial pressure thresholds for defining hypotension. Both absolute thresholds and thresholds relative to a baseline blood pressure were chosen based on the most frequently used definitions. Patient carotid-femoral pulse wave velocity determination, preoperative preparation, and induction of general anaesthesia were standardized.ResultsOur study included 115 patients. Both univariate and multivariate analysis showed that carotid-femoral pulse wave velocity was significantly associated with post-induction hypotension when defined as a systolic arterial pressure decrease of &gt; 30% or &gt; 40% from baseline or as a mean arterial pressure decrease of &gt; 40% from baseline. Also, carotid-femoral pulse wave velocity was positively associated with duration of post-induction hypotension.ConclusionsPreoperative assessment of arterial stiffness identifies patients at risk of a pronounced decrease in blood pressure during induction of general anaesthesia.

High-power mid-infrared difference-frequency generation based on synchronous pulse induction (Invited)

High-power mid-infrared difference-frequency generation based on synchronous pulse induction (Invited)

Close-Range Electromagnetic Tracking of Pulse Induction Search Coils for Subsurface Sensing

In this article, we investigate a specific search coil tracking problem arising from the use of electromagnetic induction (EMI) sensors to classify buried low metal objects. In the proposed approach, a moving search coil is used as a magnetic field beacon, two triaxial tunnel magnetoresistance (TMR) sensors are used as anchors, and the extended Kalman filter (EKF) is used to estimate five degrees of freedom information on coil’s relative pose. A specific feature of the analyzed application is the pulsed beacon field and the coil’s size comparable to the tracking distance. To address the resulting near-field effects and improve the tracking accuracy, we include a rigorous analytical multiloop model of the search coil into the EKF estimation algorithm and introduce a novel sensor calibration scheme. The system is experimentally validated in realistic dynamic conditions using a handheld pulse induction metal detector as a beacon, and a laboratory-grade optical tracking system with declared sub-millimeter accuracy as a source of ground truth data. For a near-horizontal zigzag scan pattern within a volume of $\sim \,\,40\times 50\times 5$ cm, our system yields mean absolute errors x- and $y$ -coordinates, $z$ -coordinates, and <0.5° for the pitch and roll angles, making it a viable solution for pose-referenced EMI sensing.

An IR Inductive Xe Laser Pumped by Pulsed Longitudinal Induction Discharges

IR laser radiation of XeI atoms in the range of 1700–2050 nm is obtained for the first time upon the pumping of xenon and mixtures of it with helium and argon by a pulsed longitudinal induction discharge. The spectrum of generation consists of two lines with wavelengths of 1733 nm and 2026 nm. The half-amplitude duration of the optical radiation is 60 ± 2 ns (FWHM).

A UV Inductive Nitrogen Laser with a Peak Pulse Power of 600 kW

A 4.5 mJ energy of generation at a half-amplitude duration of 7 ± 1 ns (FWHM) with a pulse peak power of more than 600 kW is obtained for the first time with nitrogen pumped by a pulsed induction discharge. Laser generation is achieved in the form of a ring with a diameter of around 20 mm and a width of around 2 mm at wavelengths of 337.1 and 357.7 nm.

Combined method of conservative treatment of trophic venous ulcers

This article provides information about the combined method of conservative treatment of venous trophic ulcers, using phototherapy with polychromatic polarized radiation and pulsed induction magnetotherapy in addition to the standard treatment. The article presents a clinical study of the effectiveness of this method in a group of 14 patients with venous trophic ulcers.