Magnetic Values Research Articles

Revisiting the safety limit in magnetic nanoparticle hyperthermia: insights from eddy current induced heating.


Magnetic nanoparticle hyperthermia (MNH) emerges as a promising therapeutic strategy for cancer treatment, leveraging alternating magnetic fields (AMFs) to induce localized heating through magnetic nanoparticles (MNPs). However, the interaction of AMFs with biological tissues leads to non-specific heating caused by eddy currents, triggering thermoregulatory responses and complex thermal gradients throughout the body of the patient. While previous studies have implemented the Atkinson-Brezovich limit to mitigate potential harm, recent research underscores discrepancies between this threshold and clinical outcomes, necessitating a re-evaluation of this safety limit. Therefore, in this study, through electromagnetic (EM) simulations, the complex interaction between AMFs and anatomical models was investigated. 
Approach. 
In particular, we considered a circular coil configuration placed at different positions along the craniocaudal axis of various anatomical human models. The excitation current was normalized, at different frequencies, to meet the basic restriction of local 10g-averaged specific energy absorption rate (SAR) in the human models, as defined by the exposure guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP 2020) and the standard IEC 60601-2-33 of the International Electrotechnical Commission (IEC 2022). 
Main Results. 
The resulting permissible magnetic field strength values for the reference levels set by ICNIRP (2020) for occupational and general public exposure, emerged to be up to approximately 1.4 and 3 times less than that defined in the Atkinson-Brezovich limit. The widely used limit was found to align more closely with the first level of controlled operating mode defined in IEC 60601-2-33 (IEC 2022). 
Significance. 
The results indicate that the permissible magnetic field amplitude during MNH treatment should be much lower than that in the Atkinson-Brezovich limit. This study offers valuable insights into the role of computational simulations in advancing the potential to establish a reliable metric for safety evaluation and monitoring within the clinical framework of MNH.

Relationship between cognitive impairment and hippocampal iron overload: A quantitative susceptibility mapping study of a rat model.

The aim of this study was to establish an iron overload rat model to simulate the elevated iron levels in patients with thalassemia and to investigate the potential association between hippocampal iron deposition and cognition. Two groups of iron overloaded rats and one group of control rats were used for this study. The Morris water maze (MWM) was used to test spatial reference memory indicated by escape latency time and number of MWM platform crossings. The magnetic susceptibility value of the hippocampal tissue, a measure of iron deposition, was assessed by quantitative susceptibility mapping (QSM) and was correlated with spatial reference memory performance. The iron content in hippocampal tissue sections of the rats were assessed using diaminobenzidine (DAB)-enhanced Perl's Prussian blue (PPB) staining. The rat groups with iron overload including the Group H and Group L had higher hippocampal magnetic susceptibility values than the control rat group, i.e., Group D. In addition, the iron overloaded groups had longer MWM escape latency than the control group, and reduced number of MWM platform crossings. There was a positive correlation between the mean escape latency and the mean hippocampal magnetic susceptibility value, a negative correlation between the number of platform crossings and the mean hippocampal magnetic susceptibility value, and a negative correlation between the number of platform crossings and the latent escape time in Group H and Group L. This rat model simulating iron overload in thalassemia showed hippocampal iron overload being associated with impairment of spatial reference memory. QSM could be used to quantify brain iron overload in vivo, highlighting its potential clinical application for assessing cognitive impairment in patients with thalassemia.

Robustness of machine learning predictions for Fe-Co-Ni alloys prepared by various synthesis methods.

Developing high-performance alloys is essential for applications in advanced electromagnetic energy conversion devices. In this study, we assess Fe-Co-Ni alloy compositions identified in our previous work through a machine learning (ML) framework, which used both multi-property ML models and multi-objective Bayesian optimization to design compositions with predicted high values of saturation magnetization, Curie temperature, and Vickers hardness. Experimental validation was conducted on two promising compositions synthesized using three different methods: arc melting, ball milling followed by spark plasma sintering (SPS), and chemical synthesis followed by SPS. The results show that the experimental property values of arc melted samples deviated less than 14% from predicted values. This work further explains how structural variations across synthesis methods impact property behavior, validating the robustness of ML-predicted compositions and highlighting a pathway for integrating processing conditions into alloy development.

Below the Schwinger critical magnetic field value, quantum vacuum and gamma-ray bursts delay

Below the Schwinger critical magnetic field value, quantum vacuum and gamma-ray bursts delay

Dual-mode Low Noise Large Range Magnetic Sensor based on Giant Magnetoimpedance Effect

Magnetic sensors are widely used in the fields of navigation, transportation, robotics, automation, and medical equipment, and the performance requirements of sensors are getting higher and higher. In this article, a bimodal magnetic sensor with two advantages of a large number of processes and low noise is proposed. The sensor consists of a 640μH core-wound inductor in series with a 100pF capacitor. When the external magnetic field changes, the magnetization state of the core in the inductor changes, the inductance value also changes, while the resonant frequency and impedance value of the sensor change with the magnetic field.<br>In this paper, the giant magnetic impedance characteristics of the RLC series circuit were analyzed, and the relationship between magnetic permeability, inductance value, and external magnetic field was established, and the series resonant frequency of the circuit was simulated to calculate the characteristics of the circuit with respect to the inductance variation.Then, two test systems were set up to test the resonance frequency versus magnetic field and the noise characteristics of the sensor.<br>In impedance mode, the effects of capacitance, drive signal frequency, and static bias magnetic field on the sensor noise floor were first analyzed to determine the optimal parameters of the sensor. When the series capacitance of the sensor is 100pF, the drive signal frequency is 1MHz, and the static bias magnetic field is 7.66Oe, the sensor has the optimal performance with an equivalent noise floor of about $200 p T / \sqrt{H z} @ 1 H z$,an impedance rate of change sensitivity of 160.6%/Oe, and a linear range of about 2Oe.In the frequency mode, the sensor operates linearly up to 25Oe, and using a logistic regression model to fit the resonant frequency to the magnetic field variation, the fit reaches 0.9974, and when the static bias magnetic field is about 7.66Oe, the sensor sensitivity is about 47kHz/Oe.<br>Not only that, with commercial components costing only ¥10 and excellent performance, the sensor has great market potential compared with other common different kinds of magnetic sensors on the market.

Synthesis, characterization, crystallization kinetics of amorphous Fe74.5Zr8.5B17 magnetic nanoparticles, and magnetoelectric properties of Fe74.5Zr8.5B17/BaTiO3 composite

This work reports the facile synthesis of amorphous Fe74.5 Zr8.5 B17 magnetic nanoparticles (MNPs) through a simple NaBH4-assisted chemical reduction method. The obtained MNPs were characterized in terms of amorphous/crystal structure, morphology, magnetic properties, composition, and crystallization kinetics. The saturation magnetization value was determined as 57.83 emu/g. The crystallization peak temperatures (Tp) and activation energy were determined to be 467.18 °C and 294 kJ/mol, respectively. Additionally, the FeZrB MNPs were combined with the BaTiO3 NPs via ball milling at low speed, using a mass ratio of 30/70%, respectively and the magnetoelectric coefficient value for FeZrB/BaTiO3 composite measured at a 1 kHz AC magnetic field is approximately 8.9 mV/Oe/cm. The study outcomes may provide a platform of nanotechnology for the preparation of MNPs with adjustable properties, which will be promising for practical applications.

Synergetic effect of edge states and point defects to tune ferromagnetism in CVD-grown vertical nanostructured MoS2: A correlation between electronic structure and theoretical study

Room-temperature ferromagnetism (RTFM) exhibited by nanostructured two-dimensional semiconductors for spintronics applications is a fascinating area of research. The present work reports on the correlation between the electronic structure and magnetic properties of defect-engineered nanostructured MoS2 thin films. Low-energy light and heavy-mass ion irradiation have been performed to create defects and tune the magnetic properties of MoS2. Vertical nanosheets with edge termination in the pristine sample have been examined by field emission scanning electron microscopy (FESEM). Deterioration of vertical nanosheets is observed in low-energy Ar+ and Xe+ irradiated samples. High-resolution transmission electron microscopy (HR-TEM) analysis confirmed the sample’s crystallinity and the (002) plane formation. An appreciably high magnetization value of 1.7emu/g was observed for edge-oriented nanostructured pristine MoS2 thin films, and it decreased after ion irradiation. From X-ray photoelectron spectroscopy (XPS) data, it is evident that, due to oxygen incorporation in the sulfur vacancy sites, Mo 5+ and 6+ states increase after ion irradiation. The density functional theory (DFT) calculations suggest that the edge-oriented spins of the prismatic edges of the vertical nanosheets are primarily responsible for the high magnetic moment in the pristine film, and the edge degradation and reduction in sulfur vacancies by the incorporation of oxygen upon irradiation result in a decrease in the magnetic moment.

Microwave catalytic treatment using magnetically separable CoFe2O4 spinel catalyst for high-rate degradation of malachite green dye.

The release of toxic chemical dyes from the industrial effluent poses huge challenges for the environmental engineers to treat it. Azo dyes encompass the huge part of textile discharges which are difficult to degrade due to their complex chemical aromatic structures and due to the presence of strong bonds (-N=N-). Thus, the removal of a carcinogenic azo dye (i.e., malachite green (MG)), via microwave (MW) - assisted technology in the presence of spinel cobalt ferrite (CoFe2O4) catalyst was investigated. The synthesized CoFe2O4 nanoparticles were characterized via XRD, FTIR, TGA, VSM, and SEM-EDAX analytical techniques. The nanoparticles were found to be spherical (17.42nm), and crystalline in nature. The impact of MW power (300-700W), MW temperature (60°- 90°C), CoFe2O4 dosage (0-1.2g/L), and initial MG dye concentrations (15-100mg/L) on MG removal were studied. The maximum MG decolorization (>90%) was observed within 2min, and the remaining decolorization was completed within next 3min under the optimized condition. The reaction rates were significantly boosted by MW irradiation, resulting in faster MG degradation with pseudo second-order kinetics rate (R2 ∼ 0.99). The MW irradiation would induce the localised hotspot zones over the catalytic surface, thus promoting the reactive radical species generation, which targeted the organic pollutant achieving the higher degree of mineralization (TOC∼90%). The toxicity reduction after the MW treatment suggests that the bulky toxic aromatic chains of the dye compound might have fragmented into simpler, smaller, and less toxic compounds. The ⦁OH played a major role in the degradation of MG dye through demethylation, elimination of benzene rings, and subsequent mineralization to CO2, and H2O. No detectable leaching of cobalt (Co) metal was observed from the catalyst, which ensured the stability of Co in the catalyst. Moreover, CoFe2O4 was recovered easily after the MW treatment via external magnetic separation, due to its high saturation magnetization value (i.e., 59.5 emu/g). Additionally, cost incurred for dye removal via MW irradiation was compared ($ 308 per kg of the dye pollutant removed) with several other processes, and found on economic side in comparison. According to the findings, the microwave irradiation process assisted by CoFe2O4 treatment offers a practical, and potential approach for treating dye laden wastewater, along with the easier catalyst retrieval mechanism using magnetism.

Influence of magnetic field on phase transitions in the antiferromagnetic Potts model

Based on the replica exchange algorithm of the Monte Carlo method, the influence of an external magnetic field on phase transitions and thermodynamic properties of the two-dimensional antiferromagnetic Potts model with the number of spin states q = 4 on a hexagonal lattice was studied. The studies were conducted in the range of external magnetic field values of 0.0 ≤ h ≤ 10.0. The magnetic field is measured in relative units of exchange interaction between nearest neighbors |J1|. The magnetic structures of the ground state were obtained, and the nature of phase transitions in the considered field range was analyzed. It has been established that in the intervals 0.0 ≤ h ≤ 3.0 and 6.0 ≤ h ≤ 6.5 a first-order phase transition is observed. It is shown that at the external magnetic field values h = 3.5 and 5.5, the system is frustrated, and in the magnetic field intervals 4.0 ≤ h ≤ 5.0 and 7.0 ≤ h ≤ 8.5, the system approaches the frustration regime. It was found that strong magnetic fields (h ≥ 9.0) suppress the phase transition in the system.

Assessment of Stress-Strain State of Pipelines Based on the Measurements of Magnetic Characteristics in Field Conditions

A series of measurements on two pipeline sections made of 17G1S (17Г1С) steel using two measuring devices: magnetic multitester MMT-3 and magnetic analyser of structure KRM-C-K2M (КРМ-Ц-К2М) has been carried out. Maps of coercive force, residual magnetic induction and maximum magnetic induction on the pipes were obtained. The coefficient of loading for different cross-sections of the pipeline was calculated. Dependence of magnetic characteristics averaged over the cross-section on the coefficient of loading is plotted. It is revealed that the most dangerous for destruction cross-sections, in which the coefficient of loading exceeded the critical value of 1,2, correspond to the reduced values of coercive force and residual magnetic induction, obtained in the direction of measurement along the pipeline axis. It is shown that measurement along the axis at the top of the pipeline shows a similar relationship as for the cross-sectional averaged values, which means that in pipeline aerial crossings, measurement only at the top of the pipeline may be sufficient.

Influence of road surface type on the magnetic susceptibility and elemental composition of road dust

The aim of the study was to determine the effect of the type of road surface (asphalt and concrete) and the presence of noise barriers (acoustic screens) on the magnetic susceptibility and chemical composition of road dust collected from national roads and motorways in central and southern Poland. Four roads with asphalt surfaces and four with concrete surfaces were selected for the study. Samples were taken at three control points: in the space between noise barriers, in the space without barriers and at road exits. Magnetic susceptibility measurements and elemental composition analysis (using an energy dispersive X-ray fluorescence spectrometer) were carried out. The results showed high variability with no clear differences between samples taken from asphalt and concrete roads. Magnetic susceptibility values were higher for road dust taken from asphalt pavements near noise barriers and motorway exits, while for open space samples the susceptibility values were about 1.3 times higher for dust from concrete pavements. A similar relationship was observed for the elemental composition. The results showed no clear differences between samples taken from asphalt and concrete roads. The location of the sampling point had a greater influence on the results: the surface of noise barriers, open spaces or motorway exits. Calculated enrichment factors indicated an extremely high enrichment of dust in elements such as Cr, Cu and Zn, a very high enrichment in Pb only for dust collected at motorway exits, and a significant and moderate enrichment in other elements.

Identifikasi Cekungan Sumatera Tengah Berdasarkan Data Anomali Geomagnetik Reduce to The Pole dan Metode Half-Slope

The Central Sumatra Basin is a back arc basin which is one of the largest oil-producing basins in Indonesia. This study aims to analyze the magnetic anomaly in the Central Sumatra Basin using the Reduce to Pole and Half-Slope methods. The methods in this study include filtering magnetic data from Sumatran geological data, making a map of the total magnetic field anomaly, and carrying out a reduction transformation to the poles in the form of a monopole, followed by 3 slices of RTP data slices, then calculating Half-Slope using RTP data slices. using Matlab software. The total magnetic field value before Reduce to Pole (RTP) was in the range of -90 to 60 nT. The value after Reduce to Pole (RTP) is in the range of -140 to 190 nT. In the results of slice 1, the average depth value is 59.2 km. Slice 2 results obtained an average depth value of 35.2 km. The average depth value on slice 3 is 42.8 km. Determine the basin boundary and slice the data in the basin boundary area for analysis using the half-slope method. Obtained an average value of depth at the boundary of the Central Sumatra basin of 19.6 km.

Green Sol-Gel Synthesis of Iron Oxide Nanoparticles for Magnetic Hyperthermia Applications.

The unique properties of iron oxide nanoparticles have attracted significant interest within the biomedical community, particularly for magnetic hyperthermia applications. Various synthesis methods have been developed to optimize these nanoparticles. In this study, we employed a powdered coconut water (PCW)-assisted sol-gel method to produce magnetite nanoparticles for the first time. A comprehensive analysis of the thermal (differential thermal analysis and thermogravimetry), structural (X-ray diffraction), morphological (scanning electron microscopy with energy dispersive spectroscopy), magnetic (vibrating sample magnetometer and hyperthermia), and biological (cytotoxicity essays) properties was conducted to assess their potential for magnetic hyperthermia. Samples heat-treated at 700 °C and 400 °C (washed powder) for 4 h under argon presented only magnetite in their composition. The micrometer-sized particles exhibited ferrimagnetic behavior, with saturation magnetization values of 37, 76, and 10 emu/g and specific absorption rates (SAR) of 27.1, 19.9, and 14.1 W/g, respectively, for treatments at 350 °C (48 h), 700 °C (4 h), and 400 °C (washed powder, 4 h) under an argon atmosphere. Biological tests showed no cytotoxicity below 10 mg/mL. The findings highlight the potential of PCW-assisted synthesis as a sustainable and efficient strategy for producing pure magnetite, with powder washing preceding the heat treatment enabling the attainment of this phase at lower temperatures. Nevertheless, the micrometer-scale dimensions is observed in the morphological analysis limit their suitability for biomedical applications.

Effects of Hall Current and Thermal Radiation on the Time-Dependent Swirling Flow of Hybrid Nanofluids over a Disk Surface: A Bayesian Regularization Artificial Neural Network Approach

For automobile and aerospace engineers, implementing Hall currents and thermal radiation in cooling systems helps increase the performance and durability of an engine. In the case of solar energy systems, the effectiveness of heat exchangers and solar collectors can be enhanced by the best use of hybrid nanofluids and the implementation of a Hall current, thermophoresis, Brownian motion, a heat source/sink, and thermal radiation in a time-dependent hybrid nanofluid flow over a disk for a Bayesian regularization ANN backpropagation algorithm. In the current physical model of Cobalt ferrite CoFe2O4 and aluminum oxide Al2O3 mixed with water, a new category of the nanofluid is called the hybrid nanofluid. The study uses MATLAB bvp4c to unravel such intricate relations, transforming PDEs into ODEs. This analysis enables the numerical solution of several BVPs that govern the system of the given problem. Hall currents resulting from the interaction between magnetic fields and the electrically conducting nanofluid, and thermal radiation as an energy transfer mechanism operating through absorption and emission, are central factors for controlling these fluids for use in various fields. The graphical interpretation assists in demonstrating the character of new parameters. The heat source/sink parameter is advantageous to thermal layering, but using a high Schmidt number limits the mass transfer. Additionally, a backpropagation technique with Bayesian regularization is intended for solving ordinary differential equations. Training state, performance, error histograms, and regression demonstration are used to analyze the output of the neural network. In addition to this, there is a decrease in the fluid velocity as magnetic parameter values decrease and a rise in the fluid temperature while the disk is spinning. Thermal radiation adds another level to the thermal behavior by altering how the hybrid nanofluid receives, emits, and allows heat to pass through it.

Renewable Water Filtration Innovation From Palm Oil Mill Effluent Waste

Indonesia is the largest palm oil producing country in the world. According to data from the North Sumatra BPS in 2021, Palm Oil production was 5,311,884 tons. Every palm oil factory disposes of its liquid waste which results in waste pollution becoming a very crucial issue to be addressed immediately because it has many negative impacts. POME is rich in minerals and carbon, but POME waste is currently not fully utilized optimally. The purpose of this research is to produce the latest innovation in water filtration to realize SDGs 2045 on clean water and sanitation and to study the effectiveness of magnetic which will be applied as clean water filtration by utilizing POME waste and natural sand containing ?-Fe2O3, alumina (Al2O3) and magnetic minerals with well water as samples in this study. The combination of POME waste and natural sand with chemical synthesis and calcination methods at a temperature of 500oC as activation of activated carbon and magnetic metals. The results of the synthesis of POME and natural iron sand obtained solids in the form of black powder. In the VSM test, the magnetization versus magnetic field data of Fe3O4/activated carbon POME obtained a magnetic saturation value of 10.13 emu/g. In the XRD test results of activated carbon materials, composites of activated carbon iron oxide and iron oxide and the synthesis results have diffraction patterns similar to the XRD database from JCPDS and in the COD and BOD tests, it proves a decrease in COD and BOD levels in well water before and after filtration with a large range, this indicates the success of the filtration process. In the AAS test as an identification of Fe metal in well water samples, Fe metal becomes <0.00206 (mg/L) starting from 0.01 (mg/L).

Engineering Zn/Fe Mixed Metal Oxides with Tunable Structural and Magnetic Properties for Magnetic Particle Imaging.

Engineering magnetic nanoparticles with tunable structural properties and magnetism is critical to develop desirable magnetic particle imaging (MPI) tracers for biomedical applications. Here we present a new superparamagnetic metal oxide nanoparticle with a controllable chemical composition and magnetism for imaging tumor xenografts in living mice. Superparamagnetic Zn/Fe mixed metal oxide (ZnFe-MMO) nanoparticles are fabricated via a facile one-pot co-precipitation method in water followed by thermal decomposition with tunable Zn/Fe ratios and at various calcination temperatures. This work, for the first time, presented LDH-derived metal oxides for an MPI application. The metal composition is tunable to present an optimized MPI performance. The analytical results demonstrate that ZnFe-MMO nanoparticles at the designed molar ratio of Zn/Fe = 2:1 after 650 °C calcination demonstrate a higher saturation magnetization (MS) value and optimal MPI signal than the samples presented with other conditions. The excellent biocompatibility of ZnFe-MMO is demonstrated in both breast cancer cells and fibroblast cell cultures. In vivo imaging of 4T1 tumor xenografts in mice using ZnFe-MMO as a tracer showed that the mean signal intensity is 1.27-fold higher than the commercial tracer VivoTrax at 72 h post-injection, indicating ZnFe-MMO's promise for prolonged MPI imaging applications.

Features of Formation of Electromagnetic Fields of Industrial and Radio-Frequency Ranges in the Conditions of the Modern Residential Development of High Number of Storeys

The tool research of electromagnetic fields of industrial frequency and radio-frequency range in by Murino of the Leningrad Region is executed. Steady excesses of admissible level of tension on borders of a sanitary rupture of the high-voltage line of 330 kV are revealed. Excesses of admissible levels of magnetic induction and in the radio-frequency range – energy stream density are not revealed. It is established that the difference of values of electric field strength in 1.8 m from a surface and at the height of 72 m reaches 1–2 orders that can be explained only with the grounding Earth’s surface role. Considerable divergences of the settlement and measured values of tension and magnetic induction are revealed that means insufficiently correct account when calculating electrophysical properties of air. The detailed cards of density of a stream of energy showing a difficult, but steady picture of distribution of values are created. Some elements of territorial structure of electromagnetic fields of radio-frequency range – fragments of rings around base stations of cellular communication, and the auras dated for certain houses are revealed.

Exploring the structural, optical, magnetic, and antibacterial characteristics of hydrothermally synthesized α-Fe2O3/rGO nanocomposites

Abstract Hematite (α-Fe2O3) and its composites have garnered significant interest due to their outstanding features, making them promising candidates for a wide range of applications in photocatalysis, water splitting, gas sensing, and antibacterial fields. This study describes the synthesis of hematite and reduced graphene oxide (rGO) nanocomposites via a facile hydrothermal method, producing three samples using 0.018 g (FG1), 0.036 g (FG2), and 0.072 g (FG3) of graphene oxide (GO). The prepared nanopowders were subjected to versatile characterizations for studying their morphological, structural, optical, and magnetic characteristics. The growth of the rhombohedral structure of hematite was confirmed by analyzing x-ray diffraction patterns, and the production of nanocomposites was verified by Raman and infrared spectroscopy. According to electron microscope images, increasing the content of GO in the precursor solution caused the change of the morphology from large rhombus and cubic shapes with sizes of about 180 nm to worm-like nanoparticles with a length of about 90 nm and a mean diameter of 25 nm. The magnetic hysteresis loops of the composite samples reflect their ferromagnetic characteristics, with saturation magnetization (Ms) values of 0.02235, 0.14990, and 0.0608 emu g−1 for FG1, FG2, and FG3 samples, respectively. Lastly, the antibacterial activity of the nanocomposites was screened against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria, and the results indicated that the growth of both bacterial strains was inhibited by all synthesized nanoparticles.

Structural, Magnetic, and Mössbauer Study on Nb and Heat Treatment of Fe-Si-B-P-Cu-Nb Ribbons

This study aims to enhance the amorphous formation ability and magnetic properties that are crucial for the production of high-quality nanocrystalline alloys. The structural, thermal, and magnetic characteristics of the alloy ribbons were analyzed through a systematic adjustment of Nb content, and, including Nb, significantly improved the amorphous formation ability and thermal stability of the alloy, which is vital for nanocrystalline production. By varying the Nb content within Fe85-xSi2B8P4Cu1Nbx (x = 0.0, 0.5, 1.0, and 1.5), we explored finer adjustments to achieve homogeneous amorphousness during the melt spinning process. Careful control over the Nb content facilitated the production of amorphous ribbons with consistent homogeneity, which was critical for the subsequent fabrication of nanocrystalline structures through heat treatment. As a result, the amorphous ribbon of Fe85.5Si2B8P4Cu1Nb0.5 showed a low coercivity of 7 A/m. The heat treatment showed a remarkably high saturation magnetic flux density of 1.94 T. Additionally, the grain size (D) decreased as the Nb content increased, with D values ranging from 25.09 nm to 24.29 nm, as calculated by the Scherrer formula. Mössbauer spectroscopy confirmed the formation of nanocrystalline and residual amorphous phases. The hyperfine magnetic field values (Beff) decreased from 25.7 T to 24.7 T in the amorphous samples and reached 33.0 T in the nanocrystalline phases. This study highlights Nb’s positive impact on thermal stability and amorphous formation capacity in Fe-Si-B-P-Cu alloys, culminating in the successful fabrication of nanocrystalline ribbons with superior structural and magnetic properties.

Analysis of the impact of magnetic and electric fields on the environment within the free space of SUTT segment Ulee Kareng - Banda Aceh

Abstract Public concerns exist regarding the potential negative impacts of magnetic and electric fields generated from SUTT lines on the environment and health. This study investigates the validity of this public concern by measuring and analyzing the magnitude of the magnetic and electric fields to determine if they remain within safe limits according to SNI, IRPA, and WHO standards. The study aims to mitigate the negative impact of SUTT on research locations including highway areas, plantations, rice fields, and brick houses, chosen using purposive sampling. This study found that the highest electric field value was measured in the plantation area at point A2 (2.1367 kV/m) and the lowest in the brick house area at point A5 (0.1795 kV/m). The highest magnetic field value was measured in the rice field area at point A5 (1.6363 μT) and the lowest in the road area at point B2 (1.5517 μT). SUTT operators monitor the magnetic and electric fields around the transmission area to ensure that the values remain within safe limits. Therefore, it is recommended to manage the vegetation around the transmission area to prevent interference with SUTT performance and to ensure that vegetation does not become an unwanted electrical conduction path.