Electromagnetic Pressure Research Articles

Accessing the Characteristics of Nuclear Reactions: A Radioactive Decay and Half-Life Measurement Study

This study investigates the impact of external environmental factors, specifically electromagnetic fields and pressure variations, on the decay constants and half-lives of three radioactive isotopes: 60Co, 137Cs, and 226Ra. By conducting controlled laboratory experiments, the research aimed to quantify the extent to which these factors influence decay rates, challenging the traditional assumption of invariant half-lives. The isotopes were exposed to varying levels of electromagnetic fields (0-100 Gauss) and pressure (1-10 atm), with decay rates measured using high-resolution gamma-ray spectrometers. The results revealed that while 137Cs exhibited the most significant sensitivity, with a 13.04% increase in decay constant under extreme conditions, 60Co and 226Ra showed moderate and minimal changes, respectively. These findings have important implications for fields such as nuclear medicine, radiometric dating, and nuclear waste management, where precise knowledge of decay rates is crucial. The study contributes to a deeper understanding of nuclear decay processes and highlights the need for further research on the effects of other environmental factors, such as temperature and chemical composition, on radioactive decay.

Polyvinyl alcohol /chitosan biomimetic hydrogel enhanced by MXene for excellent electromagnetic shielding and pressure sensing

Traditional electromagnetic shielding materials are difficult to realize practical applications due to excessive fillers, poor mechanical properties, and difficulty in preservation, etc. Hydrogel is a biomaterial with good biocompatibility and sustainability, which not only can overcome the aforementioned issues, but its biomimetic hierarchical porous structure also enables multifunctional applications. In this paper, a honeycomb-like unidirectional porous wall structured hydrogel is prepared by a simple freeze-thaw cycle and salting out method. Polyvinyl alcohol (PVA) and chitosan (CS) form a double cross-linked network (DN) enhanced by MXene, resulting in excellent mechanical and flexibility. Due to the synergistic effects of MXene, water, Fe3O4, abundant interfaces and micrometer porous wall structure, the electromagnetic shielding performance is enhanced. EMI SE increases by 30.7 dB as the MXene concentration increases from 0 to 1.5 wt%, and EMI SE increases from 7.9 to 66.7 dB as the water content increases from 0 to 76 %. Besides this, we encapsulate the hydrogel into a simple sensor, the signal response is rapid, the response /recovery time is 50/100 ms respectively, and it exhibits good sensitivity (0.0187 kPa−1). Different signals are generated based on variations in pressure, which holds significant importance for the development of wearable flexible sensors and information encoding.

Multifunctional MXene/rGO aerogels loaded with Co/MnO nanocomposites for enhanced electromagnetic wave absorption, thermal insulation and pressure sensing

Multifunctional MXene/rGO aerogels loaded with Co/MnO nanocomposites for enhanced electromagnetic wave absorption, thermal insulation and pressure sensing

Plasma propagation velocity dependence on driving and restricting forces

According to the time-averaged expression for an alternating electric field, the normalized electromagnetic pressure is proportional to the square of the voltage intensity and inversely proportional to the square of the voltage repetition frequency. Moreover, the plasma propagation velocity is either directly proportional, inversely proportional, or nonproportional to the normalized electromagnetic pressure at all neutral gas flow rates. Because the plasma current is only directly proportional to the normalized electromagnetic pressure at all neutral gas flow rates, the dependence of the plasma density on the electromagnetic pressure changes to obtain a balance of dependence. In the momentum transfer equation, plasma density does not originally depend on electromagnetic pressure, but the dynamic pressure associated with the neutral gas flow also exerts a force on the plasma through collisions. Therefore, when the ionization generation of plasma by collisions between the plasma and neutral particles is dominant over recombination by collisions, the plasma density is square proportional or directly proportional to the electromagnetic pressure.

Role of material properties on metal transfer dynamics in gas metal arc welding

In the gas metal arc welding (GMAW) process, metal transfer dynamics, influenced by wire material properties such as electrical conductivity and surface tension, serve as key sources of mass and heat for metal deposition on substrates. To elucidate the role of these material properties on metal transfer dynamics from a driving force perspective, this study examined molten droplet elongation across five distinct wires: Al, Cu, Fe, Ni, and Ti. Additionally, a unique non-transferred arc welding setup equipped with a consumable wire anode and two tungsten cathodes was introduced, allowing for observations at minimized arc lengths and preventing current concentration in molten droplets. For Al and Cu wires, while only projected-spray transfer was observed under sufficient arc length conditions, a shift to minimized arc length resulted in significant droplet elongation and a transition to streaming-spray transfer. This contrast emphasized the impact of high electrical conductivity in reducing the internal gradient of electromagnetic pressure and inhibiting the occurrence of streaming-spray transfer. Further substantiating this mechanism, Fe, Ni, and Ti wires revealed that higher electrical conductivity corresponded to an increased transition current to streaming-spray transfer. Additionally, surface tension played a crucial role in the formation of molten droplets and ensured transfer stability, with its influence varying at different current levels. These insights contribute to our comprehensive understanding of arc plasma and molten metal interactions. Our study proposes material-specific strategies to optimize metal transfer dynamics, leading to enhanced control over weld bead formation and overall mechanical properties of welded joints in the GMAW.

An Analytical-Based Lightning-Induced Damage Model for an Aircraft Wing Exposed to Pressure Loading of Lightning

Lightning is one of the natural hazards that any aircraft may encounter while navigating. If adequate precautions are not taken against lightning, structural damage, operational disruptions, and loss of life and property can occur. Thus, studying the mechanism of damage caused by lightning strikes in an aircraft’s structural material is necessary to optimize the structure, minimize the damage, and reduce the cost caused by lightning. In the present article, the lightning-induced damage behavior of an aircraft structural material was investigated from an analytical perspective. For this purpose, two analytical-based models were developed: an improved electromagnetic pressure impact model (IEPIM) and the damage model in an aircraft wing. For the IEPIM, the findings of the article showed that the proposed pressure model is in good agreement with the experimental studies, borrowed from the open literature, for 100 and 200 kA lightning current. For the damage model, the findings of the article indicated that (i) even though lightning strikes to the regions with the same characteristics on an aircraft wing in terms of the lightning strike zone, the amount of deflection in the wing increases as the impact point approaches the wing tip and decreases as it approaches the wing root, (ii) without changing the lightning strike point (x0), when the damping coefficient (ξ) is increased in the range of 0,2ξ, the amount of deflection decreases as the amount of damping coefficient increases, and (iii) when lightning with a current of 100 kA hits to the wing root of an aircraft, the pressure impact of the lightning causes more torsion deflection than bending deflection at the wing root; however, when it hits to the mid-wing or wing tip of an aircraft, the pressure impact of the lightning causes more bending deflection than torsion deflection at the mid-wing or wing tip.

Characterizing the flexural/damage behavior of Aluminosilicate glass at low/high loading rates: Application of SHPB for mode-1 loading of laminated glass

Understanding the flexural response of monolithic and laminated glass is essential for making informed choices while selecting glass for varying applications. That is because the behavior of monolithic and laminated glass may not necessarily be the same under certain loading conditions and assessing their performance differences helps in determining their suitability for specific applications. The presented work is aimed at quantifying the flexural/damage behavior of monolithic and laminated glass. Quasi-static and dynamic flexural tests were conducted on monolithic and laminated glass in mode-1 loading while maintaining identical loading and support interfaces. In the first phase, quasi-static flexural tests were performed, and results were quantitatively compared by two approaches: Effective Thickness Approximation (ETA) and the theory of Thick Sandwiched Beams (TSB). Experimentally observed deflection corroborated with both the analytical methods; the absolute error remained less than 2.5% and 0.5% for ETA and TSB, respectively. Importantly, failure of the laminate was witnessed at approximately 50% lower force compared to its monolithic counterpart, which was attributed to the span length of the specimen and the interlayer’s shear stiffness. Fractography was performed to elicit Aluminosilicate glass’s mirror constant and fracture surface energy, as 1.86 MN/m3/2 and 3.95 J/m2, respectively. In Phase-2, Dynamic flexural tests were conducted on a novel Electromagnetic Split Hopkinson Pressure Bar (ESHPB), and an experimental-numerical coupled approach was introduced to analyze the results. The results established that the adverse effects of shorter span length on the flexural strength of laminated glass are mitigated, primarily due to the viscoelastic response of the interlayer. The reprographic images attributed the fracture of monolithic and laminated glass specimens solely to the bending-induced stresses.

The microscopic Ampère formulation for the electromagnetic force density in linear dielectrics

We present a detailed derivation of the electromagnetic force density and pressure in linear dielectric media according to the so-called microscopic Ampère formulation, which considers the classical dipolar sources in matter along with the hidden momentum contribution. It is seen that, among the other formulations existing in the literature, our proposal is the only one universally compatible with the experimental works reported to date. A new radiation pressure equation for non-magnetic dielectrics under oblique illumination from p-polarized beams is also derived.

Electrically-driven textiles using hierarchical aramid fiber

High strength and flexible electronic textiles show promise in aerospace, robotics, and extreme environment applications, while it is indispensable to develop functionally integrated fiber building blocks with durable materials performance. Here we report multifunctional sensory e-textiles driven by using copper-grafted polyaramid (Kevlar®) fiber networks for the integrated electromagnetic interference shielding, thermal and pressure sensing. The hierarchical structural design and synthesis of flexible conductive networks is accomplished via the synergistic coordination between molecular copper complex and Kevlar® fibers, which facilitate long-term cyclability, stability, and washability. Superior Joule heating capabilities with a rapid thermal response under a low driving voltage (with a heating rate of 6 ºC/s and a cooling-down rate of 5.8 ºC/s), together with a high level of EMI shielding (71 dB from 8 to 13 GHz), resulting from its multilayered, vertically-aligned structure with continuous percolation of conductive coating. This work presents a new and feasible grafting approach for the large-scale fabrication of multifunctional wearable e-textiles.

Factors Influencing the Expansion of Arch-Shaped Electromagnetic Railguns with Pre-Stressed Composite Barrels.

Rail expansion significantly impacts the launch precision of a railgun system. Higher precision can be achieved when the extent of expansion is low. This paper investigates three main factors that influence the extent of rail expansion using the finite element method, including pre-stress, electromagnetic load, and stiffness of the insulators. The mean squared error between experiment results and simulating results is less than 0.06, validating the finite element model. The simulated results reveal that the extent of rail expansion increases with a decrease in pre-stress and an increase in electromagnetic pressure and the stiffness of the insulator is the most significant influencing factor, as the use of a stiff insulator not only results in a small extent of rail expansion but also delays the separation between the rails and insulators. The mechanism of how pre-stress influences the railgun system has been proposed. It has been expressed that the pre-stress maintains the integrity of the railgun system by hindering the process of a decrease in the contact surface area between rails and insulators during launch. The study provides a platform to improve the design of the railgun system.

Comparative study on the dynamic compressive, tensile and flexural properties of soda-lime silicate glass

The mechanical behavior of brittle solids are influenced by many factors such as specimen sizes, surface conditions and loading conditions. This work focused on the mechanical properties of a soda-lime silicate glass under three kinds of loading, i.e. compression, tension and flexure. In addition, quasi-static, dynamic uniaxial-unidirectional (UU) and uniaxial-bidirectional (UB) tests were performed. Electromagnetic split Hopkinson pressure bar (ESHPB), a newly developed system, was adopted in the dynamic tests. A high-speed camera was employed to capture the dynamic failure process. Effects of loading rates, specimen sizes, stress waves and loading modes on the mechanical behavior of this glass were comparatively investigated. Testing results illustrated that specimen size and strain rate had significant influence on the strengths. Different from the tensile and flexural strengths, the compressive strength was sensitive to the loading stress waves. The flexural strength was generally higher than the tensile one and they could be mutually converted through the non-local failure theory. Fracture surface of glass fragment after tensile loading was observed by a scanning electron microscope (SEM) to reveal the microscopic features.

Rayleigh-Taylor instability in an adiabatic-radiative rare plasma

Considering the particle nature of photons, the impact of electromagnetic radiation pressure is examined on the Rayleigh-Taylor instability (RTI) in a non-uniform rare magnetoplasma. For low-density and high-temperature rare plasma, the RTI with radiation pressure is revisited in the adiabatic limit. The growth rate conditions and propagating modes are derived using the framework of a developed fluid model. For specific values of ion temperature, the cut-off values of propagation of the fringing instability is found to be temperature dependent. A numerical comparison of the present results with previous work Maryam N, Rozina C and Ali S (2021, IEEE Transactions on Plasma Science 49 1072–1078) is displayed in table 1. It is found that the radiative acoustic speed is increased due to electromagnetic radiation pressure in rare plasmas as compared to radiative acoustic speed in dense plasmas. However, the growth rate of RTI increases comparatively as function of radiation pressure in rare plasmas. The present findings reveals that the consequences of RTI are remarkably concerned with the choice of electromagnetic radiation pressure either in dense (astrophysical) or rare (laboratory) plasmas. These findings are relevant to the observations of long-lived irregularities for explaining the gravitational instability in laboratory plasmas, e.g. in fusion devices like tokamaks.

Study on Load-Bearing Characteristics of Converter Trunnion Bearing

In order to improve the load-bearing performance of converter trunnion bearing, this paper proposes magnetic-hydraulic bearing which is a new coupled support technology that combines electromagnetic support and hydrostatic support. It can be realized the active control of electromagnetic and hydraulic pressure, and is conducive to extending the bearing replacement period. Based on the magnetic-hydraulic coupling, a mathematical model of the initial state of the radial support system is established, the calculation formula of bearing capacity of radial magnetic fluid bearing is deduced, and Matlab software is used to analyze the variation trend of bearing capacity and stiffness with rotor displacement. The optimization of structural parameters was carried out according to analysis of bearing characteristics, and it was concluded that the bearing performance was the best when the diameter of the bearing cavity was 10 mm, and the bearing capacity increased significantly when the thickness of the oil film was 70 μm. It provides a theoretical basis for the innovative design of converter trunnion support system.

PLC Modification of Lubrication System for Mining Dump Trucks

The automatic lubrication system of the mining dump truck is provided with pressure by a hydraulic gear pump. The pressure sensor provides real-time working pressure feedback for the lubrication system, serving as a basis for the electromagnetic pressure relief valve control system. The lubrication condition of the articulated bearings in the mining dump truck has a significant impact on the truck's utilization rate. Proper lubrication is directly related to extending equipment lifespan and reducing equipment maintenance costs. By researching and analyzing the principles of the automatic lubrication control system for mining dump trucks, and considering the characteristics, types, and maintenance difficulties of lubrication system failures, we propose a PLC modification to the original control system. This modification aims to enhance system operational stability and reduce maintenance costs.

Structural optimisation of the DEMO alternative divertor configurations based on FE and RBF mesh morphing

The DEMO tokamak exhibits extraordinary complexity due to the constraints and requirements pertaining to different fields of physics and engineering. The multidisciplinary nature of the DEMO system makes its design phase extremely challenging since different and often opposite requirements need to be accounted for. Toroidal field (TF) coils generate the toroidal magnetic field required to magnetically confine the plasma particles and support at the same time the poloidal field coils. They must bear tremendous loads deriving from electromagnetic interactions between the coil currents and the generated magnetic field. An efficient tokamak design aims at minimizing the energy stored in its magnetic field and hence at reducing the toroidal volume within the TF coils whose shape would hence ideally mimic co-centrically the shape of the plasma. In order to bear the enormous forces a D-shape is most suitable for the TF coils as it allows them to resist the very large compression on the inner side and to carry the electro-magnetic (EM) pressure mainly by membrane stresses preventing large bending to occur on the outer side. At the same time the divertor structures must fit within the TF coils and this requires adaptations of the TF coil shape in the case of so-called advanced divertor configurations (ADCs), which require larger divertor structures. This article shows the TF coils adapted to ADCs using a structural optimisation procedure applied to the reference shape. The introduced strategy takes as structural optimum the iso-stress profile associated to each coil. A continuous transformation, based on radial basis functions mesh morphing, turns the baseline finite element (FE) model into its iso-stress counterpart, with a series of intermediate configurations available for electromagnetic and structural investigations as output. The adopted strategy allowed to determine, for each of the ADC cases, a candidate shape. Static membrane stress levels during magnetization could be reduced significantly from more than 700 MPa to below 450 MPa.

On charged photons in unmagnetized dusty plasma instabilities

Motivated by the expanding interest in complex plasmas, we discuss the equivalent photon charge in dusty electron-ion plasmas. Particularly, we investigate the dusty plasma response in terms of the electron density perturbation driven by electromagnetic waves. The resulting polarization of this plasma medium caused by the photon ponderomotive force of the electromagnetic radiation pressure gives rise to an effective photon electric charge. We determine the acquired photon charge in terms of the involved characteristic parameters. More precisely, here we derive an explicit expression of the photon charge which is found to depend strongly on the free electron density and the photon frequency. Such a photonic charge is relevant for dealing with the photon–plasma couplings in most plasma mediums, namely of the early Universe.

Development of a process for thin metal plates with electromagnetic pressure and surface tension

In this study, a new method of producing silicon crystal substrates is proposed as an alternative to conventional methods. The proposed method is characterised by the continuous production of plates from molten materials by surface tension and a reduction in the plate thickness by the compression effect of electromagnetic pressure. Low-melting point alloys were used in the experiments instead of silicon. In previous studies, the inefficient application of electromagnetic pressure to the molten metal and a reduction in the width of the produced substrate have been issues. Therefore, this study improved the coil shape used to apply electromagnetic pressure and to reduce the Laplace pressure acting on the liquid surface at the side edges of the molten metal, which is considered the cause of the plate width reduction. By reducing the number of coil turns, electromagnetic pressure was effectively applied to the molten metal part, the magnetic field frequency was increased and heat generation was reduced. The increased frequency was expected to enable the effective application of larger electromagnetic pressure. In addition, there was an increase in the local thickness at the side edges of substrates by installing grooves in the exit stage of the crucible, which reduced the Laplace pressure and facilitated the production of substrates with the prescribed width. Substrate production experiments were conducted with a reshaped coil and a crucible with grooves in the exit stage section, and substrates with thicknesses of less than 100 μm in several locations were successfully produced.

On force generation in electro-fluidic linear actuators with ferrofluid

In ferrofluid actuation systems, forces are generated by actively controlling pressure and flow within the fluid using an applied magnetic field. There are multiple contributing factors in force generation involving complex non-linear couplings between electromagnetic and fluid pressure fields. This brings significant challenges in theory-based design and optimization. In this paper, a theoretical model of pressure transmission between a ferrofluid and solid is derived starting from Maxwell’s stress tensor and accounting for magnetic saturation within the fluid. This model shows that linear actuator designs based on orthogonal mode operation, where the field direction through the fluid is perpendicular to the motion direction, can provide the highest force capacity for a given field strength from the actuator coil. This is verified by theoretical analysis of some basic linear actuator topologies. The results are applied in the design and analysis of a novel piston-type linear actuator with sealed chamber and two internal electrical coils for bidirectional operation. Experimental measurements of both static and dynamic behaviour are shown to validate the described principles. The actuator produces smooth and precise flow-regulated motion, has zero intrinsic stiffness, and exhibits very low friction due to the suspension effect from ferrofluid layers within the actuator.

Pressure of Electromagnetic Radiation on a Thin Linear Vibrator in a Waveguide

The problem of electromagnetic wave pressure on a thin conductive vibrator located in a rectangular waveguide is solved. Wave H10 falls on the vibrator. The vibrator is located perpendicular to the wide wall of the waveguide. The current in the vibrator arising under the action of the electric field of the wave is calculated. The current distribution along the vibrator is almost uniform. The current in the microwave range depends little on the vibrator conductivity. Two components of the magnetic field - longitudinal and transverse exist in the H10 wave. When these components interact with the current in the vibrator, forces arise, acting on the vibrator across the waveguide and along it. The magnitude of the longitudinal force is greatest when the vibrator is located in the middle of a wide wall. It is almost 2 times greater than the force acting on the vibrator in free space at the same average radiation intensity, When the vibrator length is close to half the radiation wavelength, the force is maximum. The transverse force is determined by the interaction of the current in the vibrator with the longitudinal component of the magnetic field in the waveguide. It is maximum when the vibrator is located at the distance of ¼ of the length of the wide wall from its middle. If the length of the vibrator is less than half the wavelength of the radiation, the force is directed towards the axis of the waveguide, otherwise - in the opposite direction. The possibility of using microwave radiation pressure to create micromachines and to control the position of the vibrator in space has been evaluated. This requires a radiation power of several watts.

Evaluation of mode II fracture toughness under high loading rate conditions for composite bonded joints

Composite bonded joints are widely used in the aircraft components, which are frequently subjected to impact loading. The present paper intends to evaluate the mode II fracture behavior of composite bonded joints under high loading rate conditions. Dynamic loading was applied on the end-notched flexure (ENF) specimen at 10 m/s and 15 m/s via an electromagnetic split Hopkinson pressure bar system. Then the dynamic fracture toughness was evaluated using an experimental-numerical hybrid method according to the virtual crack-closure technique and compared to the fracture toughness under quasi-static loading rate (2 × 10−5 m/s and 2 × 10−4 m/s). Results indicate that the mode II fracture toughness of adhesively bonded composite joints shows a positive rate-dependent trend. The mode II fracture toughness can increase about 31.5% when the loading rate increases to 15 m/s. At last, fracture surface inspections using scanning electron microscopy (SEM) were conducted to reveal the physical mark of such an effect.