Electromagnetic Induction Field Research Articles

Revolutionizing Airborne Virus Defense: Electromagnetic MXene-Coated Air Filtration for Superior Aerosol Viral Removal.

The COVID-19 pandemic sparked public health concerns about the transmission of airborne viruses. Current methods mainly capture pathogens without inactivation, leading to potential secondary pollution. Herein, we evaluated the inactivation performance of a model viral species (MS2) in simulated bioaerosol by an electromagnetically enhanced air filtration system under a 300 kHz electromagnetic induction field. A nonwoven fabric filter was coated with a 2D catalyst, MXene (Ti3C2Tx), at a coating density of 4.56 mg·cm-2 to absorb electromagnetic irradiation and produce local heating and electromagnetic field for microbial inactivation. The results showed that the MXene-coated air filter significantly enhanced the viral removal efficiency by achieving a log removal of 3.4 ± 0.15 under an electromagnetic power density of 369 W·cm-2. By contrast, the pristine filter without catalyst coating only garnered a log removal of 0.3 ± 0.04. Though the primary antimicrobial mechanism is the local heating as indicated by the elevated surface temperature of 72.2 ± 4 °C under the electromagnetic field, additional nonthermal effects (e.g., dielectrophoresis) on enhanced viral capture during electromagnetically enhanced filtration were investigated by COMSOL simulation to delineate the potential transmission trajectories of bioaerosol. The results provide unique insights into the mechanisms of pathogen control and thus promote alternative solutions for preventing the transmission of airborne pathogens.

The Metabolic Process After Lubrication of Human Joint and Skin Surfaces

Purpose The topic of the presented paper concerns the human body and joint cartilage run-walk treatment implemented by the Electro-Magnetic (EM) and Acoustic Emission (AE) field. The thesis is proved here i.e. running in presence of a EM and AE field, increases dynamic viscosity of bio-lubricant liquids, thus increases energy burn, metabolism and finally it leads to the decrements of the body weight and hence it accelerates the slimming process. Material and Methods The research methods used in this paper include the following: EM field produced by a new Polish Apparatus MF-24, MT-3, Germany Magcell Arthro magneto electronic devices for the human body and joint cartilage treatment, Bone Dias Apparatus applied in AE therapy produced in Germany, ( Univ. Applied Science Giessen), Segmental Body Composition Analyzer Tanita MC 780MA, pedometer Garmin Ltd.2015.The author gained experience in Germany research institutes, and practical results were obtained after measurements and information from students and patients. Results The EM-therapy and AE results presented in this paper concern betterments during typical human cartilage diseases and causes of the effects of the slimming process gained before and after run-walk training. The run-walk training results presented in this paper concern the effects of the slimming process gained without and after electro-magnetic field therapy. Conclusions The main conclusions obtained in this paper are as follows: The run-walk training implemented by the electro-magnetic induction field and AE leads to the increments of the dynamic viscosity of synovial fluid and human sweat, changes the internal energy contained in the human body, muscle and cartilage, hence it accelerates the slimming process connected with the body weight decrements as well the betterments effects during the therapy.

Soliton-Like Spherical Symmetric Solutions to the Electromagnetic and Scalar Nonlinear Induction Field Equations in the General Relativity Theory

In this paper, we have used the static spherical symmetric metric. The parameter of the nonlinearity fields is included in the arbitrary function characterizing the interaction between the electromagnetic and scalar fields. Taking into account the own gravitational field of elementary particles, we have obtained exact static spherical symmetric solutions to the electromagnetic and scalar field equations of nonlinear induction. Considering all forms of the solution of Liouville equation, we proved that the metric functions are regular with localized energy density. Moreover, the total energy of the nonlinear induction fields is bounded and the total charge of the elementary particles has a finite value (soliton-like). In the flat space-time, soliton-like solutions exist.

Exact static spherical symmetric soliton-like solutions to the scalar and electromagnetic nonlinear induction field equations in general relativity

In this paper, we have obtained exact static spherical symmetric soliton-like solutions to the electromagnetic and scalar nonlinear induction field equations taking into account the own gravitational field of the elementary. The results show that the metric tensor functions are regular with localized energy density. Moreover, the total energy of the nonlinear induction fields is bounded and the total charge of elementary particles has a finite value. The importance of the own gravitational field of elementary particles and the role of the nonlinearity of fields in the determination of these solutions have been proved.

Combining bi-functional Pt/USY and electromagnetic induction for rapid in-situ adsorption-combustion cycling of gaseous organic pollutant

By exploiting the superior adsorption capacity of ultra-stable Y-type zeolite (USY) and accurate input of energy by electromagnetic induction field (EMIF) technique, we successfully designed a highly energy-efficient system to eliminate gaseous toluene a common air pollutant. Pristine USY as adsorbent enriches gaseous toluene by a factor of fifteen, via room-temperature adsorption and then EMIF-driven thermal desorption. This operation model involving intermittent heating and mass transfer saves a lot of energy. Especially during temperature rising, 98.9% electric energy can be saved by the EMIF heating in comparison with conventional furnace approaches. In the bi-functional “adsorption-catalytic oxidation” 1Pt/USY, the concentrated toluene undergoes direct oxidation into CO2 rather than desorption when the EMIF heating starts, so one-step enrichment and mineralization are realized. In addition, the developed bi-functional system operates between adsorption and catalytic decomposition flexibly, which makes it ideal for cleaning VOCs emitted from intermittent sources.

Abundant Firing Patterns in a Memristive Morris–Lecar Neuron Model

Improving the neuron model and studying its electrical activities according to the real biophysical environment are significant in human cognitive brain activity and neural behavior. The complex transmembrane motion of ions on the neuronal cell membrane can establish time-varying electromagnetic fields and affect the transition firing patterns of neurons. In this paper, a threshold memristor is used to describe the electromagnetic induction and magnetic field effects of neuron cell membrane ion exchange to improve the neuron model, and a memristive Morris–Lecar (mM–L) neuron model is proposed. Numerical simulation confirms that different intensities of electromagnetic fields can produce distinct pattern transitions in electrical activities of the neuron, such as periodic bursting, periodic spiking, chaotic bursting. From the perspective of neuron’s interspike interval (ISI), the ISIs bifurcation in the multiparameter planes, ISIs firing periods, the variance of ISIs and other methods are used to find the trend of the mM–L neuron firing pattern transition. Finally, based on the 4D nonlinear differential equation of the mM–L neuron model, the complete electronic implementation of the model is designed. The output of the designed circuit is consistent with the theoretical prediction, which is extremely useful for studying the dynamics of a single neuron.

Small atoll fresh groundwater lenses respond to a combination of natural climatic cycles and human modified geology

Freshwater lenses underlying small ocean islands exhibit spatial variability and temporal fluctuations in volume, influencing ecologic management. For example, The Palmyra Atoll National Wildlife Refuge harbors one of the few surviving native stands of Pisonia grandis in the central Pacific Ocean, yet these trees face pressure from groundwater salinization, with little basic groundwater data to guide decision making. Adding to natural complexity, the geology of Palmyra was heavily altered by dredge and fill activities. Our study based at this atoll combines geophysical and hydrological field measurements from 2008 to 2019 with groundwater modeling to study the drivers of observed freshwater lens dynamics. Electromagnetic induction (EMI) field data were collected on the main atoll islands over repeat transects in 2008 following ‘strong’ La Niña conditions (wet) and in 2016 during ‘very strong’ El Niño conditions (dry). Shallow monitoring wells were installed adjacent to the geophysical transects in 2013 and screened within the fresh/saline groundwater transition zone. Temporal EMI and monitoring well data showed a strong contraction of the freshwater lens in response to El Niño conditions, and indicated a thicker lens toward the ocean side, an opposite spatial pattern to that observed for many other Pacific islands. On an outer islet where a stand of mature Pisonia trees exist, EMI surveys revealed only a thin (<3 m from land surface) layer of brackish groundwater during El Niño. Numerical groundwater simulations were performed for a range of permeability distributions and climate conditions at Palmyra. Results revealed that the observed atypical lens asymmetry is likely due to more efficient submarine groundwater discharge on the lagoon side as a result of lagoon dredging and filling with high-permeability material. Simulations also predict large decreases (40%) in freshwater lens volume during dry cycles and highlight threats to the Pisonia trees, yielding insight for atoll ecosystem management worldwide.

Physical and mechanical properties of a reversible adhesive for automotive applications

In this work, a hot-melt adhesive used by automotive industries for bonding plastic components has been modified with three different percentages of nanofiller (iron oxide) in order to make the adhesive electromagnetically sensitive and to perform adhesive joint separations. Fe3O4 particles with a weight concentration of 3%, 5% and 10% were embedded in the adhesive matrix. Single Lap Joint (SLJ) tests showed that a slight increase of the maximum load and a more ductile behaviour are obtained. The sensitivity of these modified adhesive performance to the induction heating process was studied with respect to some relevant parameters: the current (or power), the frequency of the electromagnetic induction field and the shape of the coil. Furthermore, the diameter of the hollow copper coil was modified in order to understand whether the coil temperature has an effect on the separation time. The separation time, that is an index of the time needed to reach the melt of the adhesive and the consequent SLJ separation, together with the temperature profile of the adhesives have been used to evaluate the sensitivity of these adhesives to the process parameters. The analysis on the temperature and separation time showed that the most influencing parameter is the frequency of the electromagnetic induction field. As expected, also the shape of the coil influences the separation time, in particular, the adhesive joint separated with the pancake coil showed lower values of the separation time compared to the solenoidal coils. Scanning Electron Microscope (SEM) showed that iron oxide particles tend to form small agglomerate that resulted well dispersed in the adhesive matrix. Thermogravimetric analysis (TGA) was used to verify that the separation procedure do not degrades these modified adhesives.

A new evaluation approach of World War One's devastated front zone: A shell hole density map based on historical aerial photographs and validated by electromagnetic induction field measurements to link the metal shrapnel phenomenon

Since the end of World War One, only few research is performed to understand the extent of the destruction of the first meters of soil archive at the former Belgian front zone. The only existing sources identifying the by artillery destroyed landscape are maps indicating destruction at the level of administrative communities, based on war damage inventories. Even a century after the war, there is a need to gain more detail in the historical destruction at a landscape or parcel scale. Unlike in neighboring country France, the Belgian authorities allowed a complete repopulation of the front zone, which results in an ongoing confrontation between ground workers (farmers, construction workers, archaeologists, etc.), the war's heritage (trenches, bunkers, graves, etc.) and its dangers (unexploded ordnances, UXO). Metal shrapnel and the high rate of unexploded shells (up to 30% of the fired projectiles) are typical remnants of this trench warfare. The localization of these phenomena is also useful to simulate the extent of the war's environmental impact and the intensity of possible UXO-finds. To inventorize destruction and the related metal shrapnel pollution (MSP), we propose a new mapping method based on a sampling strategy to digitize shelling densities, derived from historical aerial photographs. This data source allows us to characterize almost every single parcel in this mainly agricultural area. By classifying the derived shelling densities, destruction classes can be distinguished to describe the impact on landscape and soil archive. The translation of the destruction map into a map indicating the level of buried metal shrapnel, was possible due to the direct relation between shells, metal shrapnel and shell holes. A validation with the buried metal objects was performed with metal parameters derived from electromagnetic induction field surveys. These scan results indicated a strong relation between shelling densities and the buried metal clutter. Based on the findings in this research, we offer tools to create an accurate destruction map that can be directly related to the occurrence of WW1 relicts within the soil archive.

Identifying Ground-water Resources and Intrabasinal Faults in the Hueco Bolson, West Texas, using Airborne Electromagnetic Induction and Magnetic-field Data

We conducted a high-resolution airborne geophysical survey at the eastern margin of the basin-and-range province of the southwestern U.S. to examine the hydrostratigraphy of the Hueco Bolson and identify possible ground-water resources in this arid area. The survey, flown in 2001 over a 372-km2 area east of El Paso, Texas, acquired time-domain electromagnetic induction (TDEM) and magnetic field data. These data were used to map conductivity trends to depths of at least 200 m that are related to lateral and vertical changes in lithology, water content, water chemistry (EM data), basin geometry, and the location of intrabasinal faults (magnetic data). Pre-survey, ground-based TDEM soundings established the achievable exploration depths and demonstrated that the relatively deep groundwater (80 to 120 m) significantly influenced the transient signal and was within the exploration depth of the airborne system. Airborne EM and magnetic field data identified intrabasinal faults that influence basin-fill deposition. Conductivity-depth slices constructed from airborne TDEM data allowed lateral variations in water quality and lithology to be mapped that helped predict ground-water resource quality within these fault-bounded basins filled with alluvial, lacustrine, and eolian sediments.

Full-physics 3-D heterogeneous simulations of electromagnetic induction fields on level and deformed sea ice

AbstractIn this paper we explore simulated responses of electromagnetic (EM) signals relative to in situ field surveys and quantify the effects that different values of conductivity in sea ice have on the EM fields. We compute EM responses of ice types with a three-dimensional (3-D) finite-volume discretization of Maxwell’s equations and present 2-D sliced visualizations of their associated EM fields at discrete frequencies. Several interesting observations result: First, since the simulator computes the fields everywhere, each gridcell acts as a receiver within the model volume, and captures the complete, coupled interactions between air, snow, sea ice and sea water as a function of their conductivity; second, visualizations demonstrate how 1-D approximations near deformed ice features are violated. But the most important new finding is that changes in conductivity affect EM field response by modifying the magnitude and spatial patterns (i.e. footprint size and shape) of current density and magnetic fields. These effects are demonstrated through a visual feature we define as ‘null lines’. Null line shape is affected by changes in conductivity near material boundaries as well as transmitter location. Our results encourage the use of null lines as a planning tool for better ground-truth field measurements near deformed ice types.

Study on Three Dimensional Direct Coupling Simulation of Induction Heating for Hot Stamping

As to the conventional hot stamping furnance’s shortcomings of long heating time, easy oxidized, high energy consumption, the application of induction heating for hot stamping were studied. By using COMSOL Multiphysics software, we calculated the electromagnetic induction field and temperature field by use of the direct coupling (Direct Coupling Method) in the heating process of hot forming sheet and studied the influence of inductor device parameters (such as induction length, distance between inductor and sheet etc.) and various process parameters (such as the power supply frequency, current density, sheet thickness etc.) on heating rate and temperature distribution. That will have a good guidance on the application of induction heating to hot stamping field.

Research on the Influence of Excitation Frequency on the Sensitivity in Metal Debris Detection with Inductor Sensor

The nonferromagnetic debris is easier to be detected as the excitation frequency increases; however, the sensitivity of ferromagnetic metal debris decreases as the excitation frequency increases. This paper is aimed at finding a range of excitation frequency that fit both ferromagnetic metal debris detection and nonferromagnetic metal debris detection. The equivalent circuit of the metal debris detection system with microinductor sensor is analyzed in this paper. The formulae of relationship between the sensitivity and excitation frequency are achieved according to the equivalent circuit. The simulation model of metal debris detection with the microsensor coil is built with the Ansoft software. The equivalent inductance and the electromagnetic induction field of the microinductor sensor are simulated as the excitation frequency changed. The experimental test is carried out with the prototype of microinductor sensor. The simulation results and the test results are compared. The studies indicate that the relationship between the excitation frequency and the changing rate of sensor inductance can be described by the fitting formulae. A higher sensitivity can be obtained if a suitable excitation frequency is selected. These researches have reference value for the design of inductor sensor and the parameters setting in the experimental test.

Integration of Ge nanowire arrays in glass micro-fibers

We report on a technological route for the integration of large arrays of Ge nanowires (NWs) in a human-hair-like glass micro-fiber, the length of the micro-fiber reaching one meter. The route comprises (a) the formation of semiconductor microwire in glass insulation by capillary drawing from the bottom of a glass tube softened by a conducting Ge melt drop levitating in the high-frequency electromagnetic induction field; (b) mechanical assembly of a bundle from equal-length cut microwires which are distributed in a two-dimensional quasi-hexagonal densely packed lattice encircled by a joint glass envelope; (c) stretching of the obtained preform under proper heating conditions to reduce the diameters of the stacked together microwires; (d) repeating the cut-assembly-stretching processes for the purpose of further decreasing in transverse dimensions of constituents down to 150 nm. The fascinating incorporation of huge amounts of Ge nanowires in glass micro-fibers opens new possibilities for the development of highly integrated photonic and quantumelectronic systems.

Fabrication of high chromium cast iron and medium carbon steel bimetal by liquid–solid casting in electromagnetic induction field

The high chromium cast iron and medium carbon steel bimetal was fabricated by liquid–solid casting in electromagnetic induction field. The interfacial structure and mechanical properties were investigated. The results show that the microstructure is refined obviously and mechanical properties are improved significantly. The electromagnetic stirring can refine effectively the microstructure, and profit the diffusion of elements and obtaining of the desirable microhardness transition. The electromagnetic induction heating is beneficial to achieving metallurgical interface bonding and improving the mechanical property. Furthermore, the electromagnetic stirring compels the molten metal to scour continuously the surface of medium carbon steel, resulting in the oxides and impurities being melted or broken away from the surface.

A physical pattern recognition approach for 2D electromagnetic induction studies

We present a new tomographic procedure for the analysis of natural source electromagnetic (EM) induction field data collected over any complex 2D buried structure beneath a flat air-earth boundary. The tomography is developed in a pure physical context and the primary goal is the depiction of the space distribution of two occurrence probability functions for the induced electrical charge accumulations on resistivity discontinuities and current channelling inside conductive bodies, respectively. The procedure to obtain tomographic image consists of a scanning operation governed analytically by a set of multiple interference cross-correlations between the observed EM components and the corresponding synthetic components of a pair of elementary charge and dipole. To show the potentiality of the proposed physical tomography, we discuss the results from three 2D synthetic examples.

Models of Solar Wind Structures and Their Interaction with the Earth’s Space Environment

The discipline of “Space Weather” is built on the scientific foundation of solar-terrestrial physics but with a strong orientation toward applied research. Models describing the solar-terrestrial environment are therefore at the heart of this discipline, for both physical understanding of the processes involved and establishing predictive capabilities of the consequences of these processes. Depending on the requirements, purely physical models, semi-empirical or empirical models are considered to be the most appropriate. This review focuses on the interaction of solar wind disturbances with geospace. We cover interplanetary space, the Earth’s magnetosphere (with the exception of radiation belt physics), the ionosphere (with the exception of radio science), the neutral atmosphere and the ground (via electromagnetic induction fields). Space weather relevant state-of-the-art physical and semi-empirical models of the various regions are reviewed. They include models for interplanetary space, its quiet state and the evolution of recurrent and transient solar perturbations (corotating interaction regions, coronal mass ejections, their interplanetary remnants, and solar energetic particle fluxes). Models of coupled large-scale solar wind–magnetosphere–ionosphere processes (global magnetohydrodynamic descriptions) and of inner magnetosphere processes (ring current dynamics) are discussed. Achievements in modeling the coupling between magnetospheric processes and the neutral and ionized upper and middle atmospheres are described. Finally we mention efforts to compile comprehensive and flexible models from selections of existing modules applicable to particular regions and conditions in interplanetary space and geospace.

Accounting for the effects of widespread discrete clutter in subsurface EMI remote sensing of metallic objects

In practice, most signal processing strategies for discrimination of buried objects are clutter limited. This applies even to discrimination of shallow sizable metallic objects, such as unexploded ordnance (UXO), which are to be found predominantly in the top meter of soil. The environment typically features widespread metallic clutter from detonated ordnance or other sources. Such fragments can be numerous and are often shallower than the objects of interest. Currently, the preeminent remote sensing mode for buried UXO is ultrawideband electromagnetic induction (EMI), operating over part or all of the band from some tens of hertz up to perhaps hundreds of kilohertz. Particularly because EMI fields fall off sharply with range, signals from shallow clutter may be relatively strong and can easily obscure essential scatterer signatures. To treat this, a rational theory of EMI scattering from widespread metallic clutter is formulated and tested. For dense, well-distributed clutter, analytical rules are derived for dependence of signal strength on sensor elevation, under various fundamental excitation types. For more erratic, sparse clutter distributions, signal statistics from Monte Carlo simulations show patterns like those from the analytical rules. The dependence of clutter signal magnitude on antenna elevation is determined for both thin surface layers and for volume layers of widespread small items, and for both dense and sparse clutter distributions. These are contrasted with the patterns expected from single, larger, discrete objects of interest, and the contrast is exploited in discrimination exercises for the screening problem. For sparse clutter distributions, results from inversion processing formulations that account for the patterns of clutter statistics are compared to simple least squares treatments.

Fast and accurate calculation of physically complete EMI response by a heterogeneous metallic object

In this paper, the coupling and close-proximity effects arising between highly conducting and permeable metallic objects are exposed and analyzed, for the electromagnetic induction (EMI) frequency range (from tens of hertz up to several hundreds of kilohertz). To understand the physics of the interaction phenomena, a numerical technique is applied, consisting of the full method of auxiliary sources (MAS) at low frequencies and a combination of the MAS with thin-skin approximation (TSA) at high frequencies. Both numerical MAS-MAS/TSA and experimental studies have shown that the scattered field from a heterogeneous target generated as a simple superposition of independent responses from each part can be very different from the field determined from whole object with full internal interaction. A new numerical technique for fast and accurate representation of EMI responses for heterogeneous objects is pursued here, applicable to any three-dimensional heterogeneous object placed in an arbitrary time-varying EMI field. First, any primary magnetic field input is decomposed into the spheroidal modes over a fictitious surface surrounding the object. Then, for each input spheroidal mode, the full EMI problem including all interaction is solved using the MAS-MAS/TSA technique, and each modal response is reproduced using a compact reduced set of sources (RSS). Finally, the total response from the given target for any other excitation can be synthesized simply by calculating that primary field's constituent spheroidal modes and combining their stored responses. Several numerical examples are designed to show how an object's electromagnetic parameters, geometry, distance between objects, antenna positions, and orientations relative to the object affect the coupling. Comparisons between numerical and measured data for a machined composite object and for an actual unexploded ordnance demonstrate the superior accuracy and applicability of the MAS-MAS/TSA RSS model over simple dipole approximations, for certain classes of heterogeneous objects.

The general relativistic magnetohydrodynamic dynamo equation

The magnetohydrodynamic dynamo equation is derived within general relativity, using the covariant 1 + 3 approach, for a plasma with finite electrical conductivity. This formalism allows for a clear division and interpretation of plasma and gravitational effects, and we are not restricted to a particular space‐time geometry. The results should be of interest in astrophysics and cosmology, and the formulation is well suited to gauge-invariant perturbation theory. Moreover, the dynamo equation is presented in some specific limits. In particular, we consider the interaction of gravitational waves with magnetic fields, and present results for the evolution of the linearly growing electromagnetic induction field, as well as the diffusive damping of these fields. Ke yw ords: gravitation ‐ gravitational waves ‐ MHD.