Field Intensity Research Articles

Beryllium ten production and relative paleointensity for the past 1.2 million years

Composite curves of relative paleointensity document the evolution of the geomagnetic field intensity during the past 1.2 Million years. Several records of production of 10Be cosmogenic isotope from the 10Be/9Be ratio (referred to as Be-ratio) covering this period have also been acquired. We add here new 10Be records to the database and produce a first composite curve of beryllium production (Be-1200) for the past 1.2 Myr. We compare Be-1200 with Sint-2000 (Valet et al., 2005) and PISO-1500 (Channell et al., 2009) paleointensity curves. The three curves show similar patterns, but frequently different amplitudes. The variations in dipole moment values derived from the Sint-2000 and PISO-1500 relative paleointensity composite curves were then confronted with the geomagnetic dipole moment record derived from the Be-1200 record. The predicted amplitudes of dipole moment loss during geomagnetic excursions reconstructed from the measured in the Be-1200 record are generally compatible with those deduced from SINT-2000 and PISO-1500. More specifically, the three datasets indicate very low field intensities during the Laschamp, that are consistent with the existence of reverse directions, and to a lesser extent during other events (Iceland basin, Calabrian Ridge/West Eifel events). The two paleointensity curves show a decrease in field intensity of at least 80–90% during the reversals. The Be- derived dipole moment decreases meet the predictions for the Brunhes/Matuyama transition, but are significantly smaller than expected for the two Jaramillo transitions. Such limited variability may result from the impact of environmental factors on the Be ratios, as suggested in a previous study of the last reversal (Savranskaia et al., 2021). This comparative study of 10Be records and relative paleointensity records reveals that, in particular cases, Be ratio records can underestimate the amplitude of virtual geomagnetic dipole variation. With their respective strengths and weakness, these two approaches provide similar first-order patterns relevant to the common control by the geomagnetic moment variation.

Electro-capacitive cancer therapy using wearable electric field detector: a review

Electro-capacitive cancer therapy (ECCT), a less invasive and more targeted approach using wearable electric field detectors, is revolutionizing cancer therapy, a complex process involving traditional methods like surgery, chemotherapy, and radiation. The review aims to investigate the safety and efficacy of electric field exposure in vital organs, particularly in cancer therapy, to improve medical advancements. It will investigate the impact on cytokines and insulation integrity, as well as contribute to improving diagnostic techniques and safety measures in medical and engineering fields. Wearable electric field detectors have revolutionized cancer therapy by offering a non-invasive and personalized approach to treatment. These devices, such as smart caps or patches, measure changes in electric fields by detecting capacitance alterations. Their lightweight, comfortable, and easy to-wear nature allows for real-time monitoring, providing valuable data for personalized treatment plans. The portability of wearable detectors allows for long-term surveillance outside clinical settings, increasing therapy efficacy. The ability to collect data over extended periods provides a comprehensive view of electric field dynamics, aiding researchers in understanding tumor growth and progression. Technology advancements in electro-capacitive therapy, including wearable devices, have revolutionized cancer treatment by adjusting electric field intensity in real-time, enhancing personalized medicine, and improving treatment outcomes and patient quality of life.

Quantification of hemolysis rates from pulsed field ablation

Abstract Introduction Pulsed electric fields induce hemolysis of red blood cells as a dose-dependent effect of the electric field. Voltage pulsations induce a transmembrane potential across the cell membrane and either open up or create pores in the red cells. In isotonic conditions, the pores allow passage of potassium and sodium ions but not sucrose or hemoglobin, and leakage of ions leads to an osmotic imbalance which in turn causes a colloidal hemolysis of the red cells. Objective To quantify hemolysis rates during pulsed field ablation (PFA). Methods We created a computational model of PFA to determine the total volume of blood hemolyzed from each pulse during catheter ablation using pulsed field energy. The percentage hemolysis was calculated as a function of electric field intensity utilizing existing published experimental data. A single electrode delivering a single pulse of 100 microseconds duration was modeled at voltages of 1 kV, 1.5 kV, and 2 kV. Results The total volume of hemolyzed blood per pulse increased with increasing applied voltage (Figure). For 2 electrodes in direct tissue contact, the electrode surface exposed to the blood pool generated 19 microliters of hemolyzed red blood cells with a single pulse of a 2 kV field strength. In the case of a single pulse train consisting of 50 pulses, using a catheter configuration with 20 electrodes, an estimate of total volume per pulse train is approximately 9.5 mL of hemolyzed blood. In the case of electrodes not in direct contact with endocardial tissue, and exposed to the blood pool, up to double this volume could be anticipated per pulse train. Hemolyzed volume can be reduced with better tissue contact (reducing exposure to blood), or potentially with the use of irrigation to dilute the local red blood cell concentration. Increased tonicity of the irrigant fluid may also reduce the osmotic pressure increases that result in hemolysis. Conclusions Typical voltages utilized in pulsed field ablation can cause significant hemolysis, which is exacerbated by inadequate tissue contact. A greater number of electrodes and number of pulses delivered increases the risk, whereas better tissue contact, and the use of irrigation, may reduce it.

STUDYING THE EFFECT OF MAGNETIC FLUX ON DIESEL FUEL LINE ON SOME PERFORMANCE AND EMISSION OF DIESEL ENGINE

This study aimed to investigation was carried out to evaluate the performance and product emission of four cylinder 4- stroke water cooled direct injection (DI) diesel engine fueled by permanent magnet exposed diesel fuel compared with diesel fuel (DF). Three levels of magnet field intensity were used including Diesel fuel exposer to 3000 Gauss (DG3), Diesel fuel exposer to 5000 Gauss (DG5) and Diesel fuel exposer to 9000 Gauss (DG9) fuel respectively. Permanent magnetic device was employed and installed on fuel line before interring high pressure fuel injection pump . The engine run at constant speed 1500rpm(revolution per minute) and loaded by two levels 4.5 kW and 9 kW represented as L1and L2 respectively. Results obtained showed that fuel DG5 registered an increased in thermal efficiency(TE) about 20.09% at load L1 compared with DF. Maximum reduction in brake specific fuel consumption (bsfc) about 12.12%, when using DG5 fuel at load 1 compared to DF fuel. All exhaust emission Unburned Hydrocarbon (UHC), Carbon Monoxide (CO), Carbon Dioxide (CO2),Particular Maters (PM), and Nitrogen Oxides (NOx) are decreased when diesel fuel treated with different magnetic intensities 3000,5000 and 9000 Gauss. Compared with conventional diesel fuel. Maximum reduction in PM,HC,NOx,CO2,and CO about 16.56-27.08%, 3.89–64.26%, 4.79–7.91%, 4.05-5.71and 11.46-53.48% respectively. CO2 emission was increased by 1.65-4.28 at DG5 with L1 and L2 respectively due to the operating conditions.

Superposition of standing waves induced ultra high-resolution atom localization

Abstract In this study, we have theoretically demonstrated ultra-high resolution two-dimensional atom localization within a three-level $\lambda$-type atomic medium via superposition of asymmetric and symmetric standing wave fields. Our analysis provides understanding into the precise spatial localization of atomic positions at the atomic level, utilizing advanced theoretical approaches and principles of quantum mechanics. The dynamical behavior of a three-level atomic system is thoroughly analyzed using the density matrix formalism within the realm of quantum mechanics. A theoretical approach is constructed to describe the interaction between the system and external fields, specifically a control field and a probe field. The absorption spectrum of the probe field is thoroughly examined to clarify the spatial
localization of the atom within the proposed configuration. We have theoretically investigated that symmetric and asymmetric superposition phenomena significantly influence the localized peaks within a two-dimensional spatial domain. Specifically, the emergence of one and two sharp localized peaks has been observed within a region of one wavelength domain. We observed notable influences of the intensity of the control field, probe field detuning, and decay rates on atom localization. Ultimately, we have achieved an unprecedented level of ultra-high resolution and precision in localizing an atom within an area smaller than λ/35×λ/35. These findings hold promise for potential applications in domains such as Bose-Einstein condensation, nanolithography, laser cooling, trapping of neutral atoms, and the measurement of center-of-mass wave-functions.

Resonance scattering generated by rotating bodies

Abstract The scattering of rotating bodies to a polarized plane wave, including the dielectric cylinder and sphere, is studied. The resonance caused by rotation is emphasized. Numerical results prove that the resonance scattering caused by rotation can be realized in the optical range. It is sensitive to the rotation dimensionless parameter γ. The internal Mie mode corresponding to the electromagnetic field intensity changes with γ, and the resonant mode appears when the particle rotates at a specific speed. Moreover, the resonant mode changes with γ. It causes resonance scattering to appear in the same particle at different speeds. Inside particles, resonant rings are composed of a series of array points and are determined by γ. Under resonance conditions, the energy near the rotating cylinder is consistent with its rotation direction. In contrast, the direction of energy flow in the rotating sphere model is opposite to the direction of particle rotation. This work provides a novel idea for the design of ultra-sensitive sensors and resonators. It has promising applications in optical communication, optical microscopy, and optical signal processing.

Study on the influence of high permeability magnetic iron on energy consumption reduction in high gradient magnetic separator

The green processing of weakly magnetic iron ore is inseparable from high-intensity and high-gradient magnetic separator (HGMS), which is one of the most energy-intensive magnetic separation equipment. Iron (Fe) armor serves as the key primary structure for enhancing magnetic field conduction efficiency within the magnetic system. The order of magnetic properties of commonly used magnetic yoke materials is: ordinary carbon structural steel < Q235 steel < DT4 electrical pure iron. But the utilization cost of DT4 electrical pure iron is the highest, especially the magnetic properties of DT4C super electrical pure iron are unstable and the yield is low. On the basis of ordinary pure iron materials, this article has developed a new type of 411 pure iron (411) upon controlling the levels of harmful elements, while increasing the concentration of beneficial elements.intensity Furthermore, through the utilization of magnetic field simulation software, the impact of 411 on the background magnetic field intensity of HGMS was analyzed. The results indicated that the newly developed 411 pure Fe exhibited a coercivity of 24.07 A/m, a saturation magnetization intensity of ∼ 1.69 T, a maximum relative magnetic permeability of 24.38 × 10-3H/m, demonstrating superior magnetic properties in comparison with Q235 and DT4C. When using 411 pure iron as the magnetic yoke material, the background magnetic field intensity of the HGMS can be increased by 6.85 % − 14.64 % compared with using DT4C super pure iron under the same excitation current conditions. The magnetic yoke with better magnetic conductivity will enhance the magnetic field utilization efficiency of the magnetic system, a reduce the excitation energy consumption, and improve the sorting performance of HGMS.

Beam quality measurement and image analysis of RF optical emission system

With the development of radio-over-fiber (ROF), beam quality is also an important parameter in evaluating ROF systems. Therefore, this paper selects the low-frequency to very high frequency (VHF) direct modulated optical emission system to verify its feasibility and excellent performance. It then analyzes the beam quality and image processing. In this paper, MATLAB is selected for the theoretical simulation, then CMOS is used to collect light spots, RayCiV2.5 is used to Gaussian fit the light field intensity distribution, and finally the ideal and actual light spot parameters are compared. Due to the influence of noise, this paper also preprocessed the image by brightness adjustment, filtering, edge fitting, etc. It proposed a fast two-sided filtering algorithm, which obtained a high peak signal-to-noise ratio (PSNR) and strong applicability. The results show that the edge-mode rejection ratio is as high as 33.6 dB, the beam quality is good, and it can be well applied in ROF. The M2 factor is 2.75, the optical field intensity Gaussian fit is 99.8 %, and the signal-to-noise ratio (SNR) is as high as 54.7 dB. Moreover, the image is robust after fast bilateral filtering.

The Assessment of the Influence of Low-Frequency Electromagnetic Fields Originated from the Power Infrastructure on Humans’ Health

The objective of this study is to assess the impact of low-frequency electromagnetic fields (LF EMFs) generated by power infrastructure on the nearby environment. Measurements of electric (E) and magnetic (H) field intensities were conducted around high-voltage power lines, transformer stations and facilities related to them. Numerical simulations were also performed to model the distribution of the field values around real buildings in close proximity to power delivery systems. Given the ongoing scientific debate regarding the effects of EMFs on living organisms, the current analysis was based on the existing standards—particularly ICNIRP 2010 guidelines, which set the maximum allowable E and magnetic induction (B) values at 5 kV/m and 200 μT, respectively. Stricter national regulations were also examined, such as Poland’s 1 kV/m E limit in residential areas and Belgium’s 10 μT limit for B. The results showed that while most cases complied with ICNIRP 2010 standards, certain stricter local regulations were exceeded. Specifically, 9 of 14 cases exceeded Poland’s E limits, and 8 failed to meet Belgium’s B requirements. Only in one place—a warehouse near 110 kV power lines (in a critical case)—the ICNIRP limit B was exceeded. These findings underscore the variability in regulatory standards and highlight the need for localized assessments of EMF exposure.

Open-loop narrowband magnetic particle imaging based on mixed-frequency harmonic magnetization response

IntroductionMagnetic particle imaging (MPI), a radiation-free, dynamic, and targeted imaging technique, has gained significant traction in both research and clinical settings worldwide. Signal-to-noise ratio (SNR) is a crucial factor influencing MPI image quality and detection sensitivity, and it is affected by ambient noise, system thermal noise, and the magnetization response of superparamagnetic nanoparticles. Therefore to address the high amplitude system and inherent thermal noise present in conventional MPI systems is essential to improve detection sensitivity and imaging resolution.MethodThis study introduces a novel open-loop, narrow-band MPI signal acquisition system based on mixed-frequency harmonic magnetization response. Allowing superparamagnetic nanoparticles to be excited by low frequency, high amplitude magnetic fields and high frequency, low amplitude magnetic fields, the excitation coil generates a mixed excitation magnetic field at a mixed frequency of 8.664 kHz (fH + 2fL), and the tracer of superparamagnetic nanoparticles can generate a locatable superparamagnetic magnetization signal with rich harmonic components in the mixed excitation magnetic field and positioning magnetic field. The third harmonic signal is detected by a Gradiometer coil with high signal-to-noise ratio, and the voltage cloud image is formed.ResultThe experimental results show that the external noise caused by the excitation coil can be effectively reduced from 12 to about 1.5 μV in the imaging area of 30 mm × 30 mm, which improves the stability of the detection signal of the Gradiometer coil, realizes the detection of high SNR, and makes the detection sensitivity reach 10 μg Fe. By mixing excitation, the total intensity of the excitation field is reduced, resulting in a slight improvement of the resolution under the same gradient field, and the spatial resolution of the image reconstruction is increased from 2 mm under the single frequency excitation (20.7 kHz) in the previous experiment to 1.5 mm under the mixed excitation (8.664 kHz).ConclusionsThese experimental results highlight the effectiveness of the proposed open-loop narrowband MPI technique in improving signal detection sensitivity, achieving high signal-to-noise ratio detection and improving the quality of reconstructed images by changing the excitation magnetic field frequency of the excitation coil, providing novel design ideas and technical pathways for future MPI systems.

Probing the magnetic fields of starspots with transit mapping

Starspots, regions of strong magnetic fields, serve as indicators of stellar activity and the dynamo mechanism at play in the interior of stars. The magnetic fields of main-sequence stars play a crucial role in driving stellar activity. An effective approach to better understanding stellar magnetic fields and activity lies in the detailed characterisation of starspot properties. We propose a new method for estimating the magnetic fields of starspots that employs modelling techniques of planetary transit mapping, which provides estimates of the size, intensity, and location of spots on the stellar photosphere. A starspot's maximum magnetic field was calculated using the linear relationship with the spot flux deficit, $ spot $ (the spot's brightness times its area) and the well-characterised relation for sunspots determined in this work, $B_ spot (G). Applying this relationship to previously mapped spots on the photospheres of 14 FGK and M stars yields spot maximum magnetic fields ranging from 2700 G to 4600 G, with an overall average of $3900 400$ G. We looked for correlations between starspot magnetic fields and stellar properties.\ We did not find any correlation between a spot's mean extreme magnetic field and effective temperature, nor the differential shear. However, a weak anti-correlation is seen between the spots' magnetic field and stellar age as well as between the magnetic field and the rotation period. When compared with previous results of small-scale magnetic field measurements, the B values obtained here are basically constant and near the saturation limit found for rapid rotators. This implies that it is not the intensity of the magnetic field of starspots that decreases with age but rather the filling factor. This result offers a unique window into the magnetic dynamo of stars.

Three-dimensional computer holography with phase space tailoring

Computer holography is a prominent technique for reconstructing customized three-dimensional (3D) diffraction fields. However, the quality of optical reconstruction remains a fundamental challenge in 3D computer holography, especially for the 3D diffraction fields with physically continuous and extensive depth range. Here, we propose a 3D computer-generated hologram (CGH) optimization framework with phase space tailoring. Based on phase space analysis of the space and frequency properties in both lateral and axial directions, the intensity of the 3D diffraction field is adequately sampled across a large depth range. This sampling ensures the reconstructed intensity distribution to be comprehensively constrained with physical consistency. A physics-informed loss function is constructed based on the phase space tailoring to optimize the CGH with suppression of vortex stagnation. Numerical and optical experiments demonstrate the proposed method significantly enhances the 3D optical reconstructions with suppressed speckle noise across a continuous and extensive depth range.

Frequency Shift Caused by Magnetic Field and Light Intensity Inhomogeneity in Optically Detected Clock

Frequency Shift Caused by Magnetic Field and Light Intensity Inhomogeneity in Optically Detected Clock

Application of the FDTD Method for Multivariate Analysis of the Influence of Conductivity and the Arrangement of Hollows Inside Bricks on the Values of Electric Field Intensity

The article contains a numerical analysis of the effects of electromagnetic wave propagation in an area containing a non-ideal, non-uniform, and absorbing dielectric. The analysis concerned the influence of the structure of the building material and its electrical parameters on the electric field intensity. The analysis took into account the variability of the number of hollows in the brick, the width of hollows, as well as the arrangement of these hollows relative to each other using the example of two types of bricks. The article also provides the most commonly used values of electrical parameters for building materials (brick, plaster). For this reason, the article includes results for different values of conductivity (0–0.2 S/m). The FDTD (Finite Difference Time Domain) method was used for multivariate analysis. The aim was to verify the correctness of the numerical assumptions adopted. Using the example of the most commonly used wall structure in construction, the results obtained using the FDTD method were compared with values obtained using another numerical method, the finite element method (FEM). The influence of an additional layer of plaster on the considered wall on the electric field was also checked. The analysis showed that a symmetrical arrangement of bricks results in higher values of the electric field by an average of 20%. Of course, this depends on the length of the hollows and the number of holes. The highest field values occur at low conductivities (0–0.04 S/m). A brick wall with a larger number of hollows and a symmetrical brick arrangement shows the highest electric field intensity, especially for hollow sizes (0.009–0.015 m).

Research on influence of stress concentration on metal magnetic memory signal for stress evaluation

Abstract Based on the magneto-mechanical effect and stress concentration effect, this paper takes the failure of ferromagnetic components caused by stress concentration as the research background, artificially creates stress concentration by prefabricating U-shaped defects, and discusses the Hp(y) signal distribution law of prefabricated U-shaped defect samples and the difference in Hp(y) signal between specimens with different tip SCFs. Results show that the Hp(y) signal has an apparent mutation in the stress concentration area, and when the stress concentration factor was the same, the magnetic field intensity gradient K becomes higher as tensile load increasing. As stress concentration factor increasing, the K value of the stress concentration area also increases gradually. Based on theoretical model of Hp(y) signal, it can be known that the K value can be used to judge the sample stress concentration degree with the results in this study.

Strain-induced modulations in nonlinear optical rectification of core/shell quantum dots within an MEH-PPV polymer matrix under electric field: a 3D finite-element modeling study

This research aims to explore how the MEH-PPV polymer matrix and the strength of the applied field (EF) affect an electron confined within strained CdSe/ZnSe spherical core/shell quantum dots (CSQDs). By solving the Schrödinger equation using the element method (FEM) and effective mass approximation we calculated eigenenergy values and their corresponding wavefunctions. Through a compact density matrix approach, we examined how the MEH-PPV polymer matrix, QDs size and electric field intensity impact nonlinear rectification (NOR), in both unstrained systems. By considering factors such as the surrounding polymer matrix and size confinement we analysed computed coefficients related to EF intensity, peak locations and shifts. Our key findings suggest that understanding NOR in relation to parameters and surrounding materials can provide insights, for improving future optoelectronic and photonic devices.

Dot-array porous medium model for windscreen and its simulation accuracy analysis

Porous medium models have long been prevalent numerical computation tools. Although they exhibit swift computational speed, their accuracy in simulating windscreen perforation structures is challenged. This paper introduces the innovative dot-array porous medium (DAPM) model, which accurately portrays the perforation structure and material characteristics of a windscreen by establishing virtual holes on the porous medium. Not only does it simplify modeling by eliminating complex perforation processes, but it also adeptly simulates the flow behavior of the windscreen. The comprehensive comparison between the DAPM model and the physical mesh model, traditional porous medium model, as well as wind tunnel test results, demonstrates that the DAPM model not only possesses rapid computational speed but also delivers outstanding precision in results. In terms of velocity distribution, vortex distribution, and flow intensity in the flow field, the model indicates a high level of accuracy, clearly exceeding that of the porous medium model. Moreover, the DAPM model showcases high versatility and adjustability in practical applications. By adjusting dimension parameters, it demonstrates the capability to precisely simulate any windscreen with holes arranged in a matrix pattern. This research provides an efficient and reliable tool for the numerical simulation of windscreens, with broad application prospects.

The High Cycle Bending Fatigue Property of Quenched Crankshaft Based on the Stress Field Intensity Method and the Multi-physic Field Coupling Numerical Simulation Approach

The High Cycle Bending Fatigue Property of Quenched Crankshaft Based on the Stress Field Intensity Method and the Multi-physic Field Coupling Numerical Simulation Approach

Analytical relations for fields and currents in magnetic-pulsed «expansion» of tubular conductors of small diameter

Introduction. This work was initiated by the problems of cardiovascular diseases, which are one of the main causes of mortality of the population of our planet. More than ten years ago, in 2012, approximately 3.7 million people died of acute coronary syndrome worldwide. The fight against such pathologies is carried out with the help of so-called stents, the manufacture of which can be carried out by the method of magnetic pulse «expansion» from hollow metal cylinders. The limited production possibilities of magnetic pulse «expansion» were caused by the minimum cross-sectional size of the inductor-instrument, which can be practically manufactured. Other tools are required to perform this operation. Novelty. A system of magnetic-pulse expansion of thin-walled pipes of small diameter with an inductor that excites an azimuthal electromagnetic field in the case of direct current passing through the processing object and in the absence of its connection in an electric circuit with an inductor is proposed. Purpose. The main analytical dependencies for the characteristics of the electromagnetic processes taking place in the inductor systems for the expansion of cylindrical conductive pipes of small diameter when direct passage of current through the processed object and when it is not connected to an electric circuit with an inductor (insulated billet) is derived. Methods. The solution of the boundary value problem with given boundary conditions was carried out by applying Laplace transforms and integrating Maxwell’s equations. Results. Analytical expressions were obtained for the main characteristics of the processes: the intensities of the excited electromagnetic fields and currents in the system depending on the parameters of the studied systems. The analysis of possible technical schemes for solving the given problem indicated the choice of the optimal variant of an effective system of magnetic-pulse «stretching» of thin-walled cylindrical conductors of small diameter. Practical value. Based on the qualitative analysis of the obtained results, recommendations for the practical implementation of the proposed system were formulated. The obtained dependences allow us to give numerical estimates of the effectiveness of excitation of magnetic pressure forces on the object of processing and to choose directions for further improvement of the magnetic pulse technology for solving such problems. References 23, figures 2.

CFD Investigation on Air-Staged Combustion Characteristics of Deep Peak Shaving Wall-Fired Burner Boilers

ABSTRACT In alignment with China’s ambitious goals of reaching peak carbon emissions and achieving carbon neutrality, stringent load peak regulations are being enforced for coal-fired power generation. This underlines the significance of deploying deep load peaking strategies in coal-fired units. The current research focus is on wall-fired boilers operating under ultra-low loads of 600 MWe. It delves into the flow dynamics, combustion characteristics, component concentration field, and NOx emission characteristics under varying air coefficients in the primary combustion zones (α). The findings suggest the formation of a consistently high-temperature region in the primary combustion zone, where temperatures surpass 1500 K. The middle burner exhibits superior combustion stability compared to the bottom burner. As α diminishes, several changes occur. The flow field intensity in the primary combustion zone lessens, the ignition distance contracts, and the O2 concentration in this area drops. This engenders a reducing atmosphere characterized by low O2 and high CO levels, which hampers the formation of NOx. At α = 0.95, the NO concentration peaks, with the primary generation mechanism being temperature-driven. At this juncture, the NO concentration at the furnace flue gas outlet is 287.36 mg/m3.