Magnetization Process Research Articles

Side-by-Side Economic Process Model for the Comparison and Evaluation of Magnetic Bead-Based Processes and Legacy Process for the Manufacturing of Monoclonal Antibodies

This study models two alternative downstream processes based on magnetic separation with the objective of understanding the economic feasibility of these processes compared to the traditional mAb process. The key focus lies in the economic understanding of the cell harvest and capture steps in the models. Here, the models revealed that integrating cell removal and product capture in a single operation is the main factor driving the unified productivity between USP and the magnetic bead-based processes. This results in significant economic benefits, such as savings in both the cost of goods per gram of mAb and fixed costs, as well as increasing annual facility output. The predicted savings potential approaches 38% for COGs, 17% for capital investment, and 40% for annual facility output. For mammalian cell-based manufacturing, the magnetic separation-based DSP provides a highly valuable option due to its integration of several individual unit operations compared to the traditional process both in reducing process time and cost and accommodating higher demands.

A Review of Direct Reduction–Magnetic Separation Process for Ferronickel Production from Nickel Laterite

A Review of Direct Reduction–Magnetic Separation Process for Ferronickel Production from Nickel Laterite

Fe-loaded two-dimensional nitrogen-doped carbon for electromagnetic wave absorption

Abstract Electromagnetic wave absorbing materials are particularly important in modern electronics, especially in the fields of stealth and communications. Carbon-based materials show great promise in the production and application of efficient wave-absorbing materials due to their rich structure, ultra-light weight, good corrosion resistance, and low cost. Among them, nitrogen-doped carbon-based two-dimensional materials have a stronger depletion effect on electromagnetic waves due to their higher specific surface area and abundant polarization states. In this article, nitrogen-doped carbon 2D flakes (NC) were successfully synthesized by a hydrothermal method. Furthermore, Fe single atoms were successfully loaded onto their surfaces, creating Fe@NC. The wave-absorbing properties of Fe@NC samples were significantly enhanced, with the minimum reflection loss (RLmin) reaching -69.22 dB at 11.48 GHz and the effective absorption bandwidth (EAB) extending to 5.79 GHz. The enhancement of electromagnetic wave absorption is attributed to the synergistic effects of magnetic loss, relaxation processes, dipole polarization, and electrical conduction loss. The successful preparation of Fe@NC offers new possibilities for the development of atomically dispersed wave-absorbing materials.

Medical Image, Analysis and Visualization using Image Processing

This project presents an automated approach for detecting brain tumor using Magnetic Resonance Imaging (MRI) and image processing techniques. Traditional methods rely on human inspection, which can be error-prone and time consuming. Our framework consists of several modules: acquiring MRI images, preprocessing to enhance image quality (including noise reduction and edge detection), and segmenting the tumor using the Watershed algorithm. We extract texture features from the segmented images using the Gray Level Co-occurrence Matrix (GLCM), focusing on metrics like energy, contrast, correlation, and homogeneity. Finally, we classify the MRI images as normal or abnormal using a Multilayer Perceptron (MLP) model. This automated detection process improves the efficiency of tumor identification, providing insights into the size, shape, and position of the tumor while alleviating the workload of radiologists.

Tracking a Homeopathic Complex Formulation in the Watercourses of a Fire-Damaged State Park in Brazil.

In 2020, a 26,849-ha state park in Mato Grosso do Sul state, Brazil, had 30% of its area damaged by fire. A homeopathic complex formulation was applied at strategic point locations in the park's springs or watercourses, aiming to mitigate the fire damage to the flora and fauna as quickly as possible. The duration of the homeopathic signal at each point was assessed using an established solvatochromic dye technique. To evaluate the timing and the nature of the signal at each of nine point locations. We could thus identify the presence of any signal variations due to specified environmental features within the park. Water samples were harvested from each intervention point at different times, filtered, frozen, and sent to the laboratory, where they were prepared to 1cH using filtered 30% ethanol. Methylene violet was chosen among six dyes since it was found in preliminary tests that it could trace the homeopathic complex used. In addition to simple sample testing, samples were submitted to a static and unidirectional magnetic field of 2400 Gauss (240 mT) for 15 minutes immediately before reading, which enhanced the method's sensitivity. One-way analysis of variance/Tukey test was used to identify dye absorbance changes following the analysis of water samples from the watercourse system. A correlation matrix and the Spearman r test were employed to evaluate any correlation between tracking and the pre-existing anthropic interventions at harvesting points. In all cases, α = 0.05. Four tracking patterns using the sample magnetization process were observed in relation to water samples and their effect on methylene violet solutions: no response (P2, P4), early transitory response (P5, P6, P8), late response (P1, P9), and constant response (P3, P7). P2 and P4, which could not be tracked, were correlated with permanent local anthropic disturbance. Methylene violet was the best dye to track the homeopathic complex prepared specifically for this case. Tracking was facilitated by prior magnetic treatment of samples, but anthropic disturbances to the environment seem to interfere with it.

Precise Methylation Detection of Tumor Suppressor Gene Promoters by Magnetic Enrichment and Nano Silver Adduct-Promoted Surface-Enhanced Raman Scattering.

Noninvasive liquid biopsies can be used for early tumor diagnosis by identifying the methylation level of the tumor suppressor genes (TSGs)-a reliable index for cancer evaluation. However, identifying trace circulating genes from specimens remains challenging. This work introduces a novel method that combines magnetic isolation and surface-enhanced Raman scattering (SERS) to concentrate and detect the methylated TSG promotors. A superparamagnetic iron oxide nanoparticle modified with streptavidin is prepared as a universal magnetic bead. Biotin-terminated probe single-strand DNA (ssDNA) is immobilized on the magnetic beads through biotin-streptavidin bioconjugation. Artificial target ssDNA fragments with various methylation levels are applied as a promoter gene model. Concentrated double-strand DNA (dsDNA) is produced by a hybridizing probe and target ssDNA on magnetic nanobeads, as well as an additional magnetic isolation process. The well-prepared DNA adduct, which consists of 3nm cisplatin-modified Ag nanoclusters, can specifically bind with guanine-cytosine base pairs of dsDNA. Ag-nanoparticle-induced localized SERS amplified signals of 5-methylcytosine (5-mC) from the dsDNA in Raman spectra, enabling accurate methylation level measurement in mixtures of 0-1µm methylated DNA, with a detection limit of 0.05µm. This method shows promise for enabling the methylation level evaluation of various TSGs and promoters in early cancer liquid biopsies.

Phase-selective fabrication of Cu-based films by magnetic field-assisted sparking process for improved photocatalytic dye degradation and CO2 reduction

Copper-based films (Cu2(OH)3NO3, Cu2O, and CuO) were successfully synthesized using a sparking process under an external magnetic field, without requiring an annealing process. We thoroughly investigate the impact of magnetic field orientation on the structural, morphological, and optical properties of the films, along with their performance in photocatalytic degradation of methylene blue (MB) and carbon dioxide (CO2) reduction. Field-emission scanning electron microscopy (FE-SEM) images reveal that the CuEB(S) sample displays secondary particles forming spherical, dense clusters, whereas the CuEB(N) sample exhibits larger, loosely packed clusters. In contrast, the cluster-like structures disperse in the CuEB(P) sample, resulting in a smoother film surface aligned with the parallel magnetic flux direction. Upon close observation, rice-shaped particles of varying sizes (26.3–60.3 nm) were found stacked together. This study presents a facile method to selectively fabricate films comprising single-phase Cu2(OH)3NO3, a CuO/Cu2O composite, or a combination of all phases by manipulating the external magnetic field orientation during the sparking process. All synthesized materials exhibit photocatalytic activity, with the heterojunction composed of CuO, Cu2O, and Cu2(OH)3NO3 demonstrating superior performance. This heterostructure achieved up to a 180 % enhancement in MB degradation and approximately doubled the CO2-to-CO conversion rate to 16.09 μmol g–¹ h–¹ compared to the sample prepared without a magnetic field.

Modeling of partially oriented spring-exchange magnetic composites

PurposeThe presentation refers to simulations of magnetization processes of the spring-exchange magnetic composites containing magnetically soft and ultra-high coercive phases. In particular, the aim of this study is to investigate the possibility of reducing expensive rare earth (RE) in the so-called neodymium magnets and improving their efficiency.Design/methodology/approachIn order to model hysteresis loops, a special disorder-based Monte Carlo procedure, suitable for irregular geometry of the composites, was applied. The chosen system parameters were defined in order to model Nd2Fe14B/Fe composites.FindingsThe results suggest potential for optimizing hard magnetic composites. Magnetization curve parameters are sensitive to grain coupling and easy magnetization axis ordering. Strong coupling for a single-phase hysteresis loop is unachievable for grains above a certain size, i.e. found to be a few hundred nanometers. Considering these factors and their interdependencies, it’s possible to enhance the |BH|max parameter or reduce the RE content.Research limitations/implicationsThe research was carried out using computer simulations, which by their nature are only approximations of physical processes. The next stage of research is to produce the described composites and test their actual properties.Practical implicationsThe research enhances permanent magnets, boosting efficiency in technologies like wind turbines and electric motors, indirectly benefiting the environment. It also reduces RE elements in magnets for environmental, economic and political gains.Originality/valueThe unique approach is to consider the random orientation of the magnetic anisotropy of the hard magnetic grains, which is close to real powder composites. The results provide valuable guidance for the production process of permanent magnets.

Optimization of Magnetic Biochar Preparation Process, Based on Methylene Blue Adsorption.

The search for low-cost and effective adsorbents for the removal of organic dyes from contaminated water is urgently needed. The substantial amount of waste mushroom cultivation substrates generated in practical production can serve as an ideal material for the preparation of adsorbents. In this study, we investigated the main control parameters affecting the performance of magnetic mushroom substrate biochar and optimized the process of preparing biochar by using the Plackett-Burman and central composite design methods. Various analytical techniques including SEM, EDX, BET, and VSM were used to characterize the biochar. The results indicate that the carbonization temperature had the most significant impact on the yield and adsorption performance of biochar. Under the conditions of a carbonization temperature of 600 °C, a carbonization retention time of 1 h, and an impregnation ratio of 0.1, the yield and methylene blue adsorption value of magnetic biochar were 42.54% and 2297.04 μg/g, respectively, with a specific surface area of 37.17 m2/g. This biochar effectively removed methylene blue from the solution, demonstrating a high economic efficiency for wastewater treatment and pollution control. Furthermore, the adsorption-desorption cycle studies revealed its excellent stability and reusability. Additionally, based on the response surface methodology, a three-dimensional surface model of the adsorption performance of magnetic biochar under different carbonization conditions was established, providing a theoretical basis for the preparation of magnetic biochar from agricultural wastes.

Chain-arranged Ni1-xCox micro/nano particles prepared via a magnetic field-assisted reduction for enhanced electromagnetic wave absorption

Transition metal magnetic alloys have garnered extensive interests in electromagnetic wave absorption due to the remarkable magnetic loss capacity and unique magnetism-frequency characteristics. Herein, we report a novel magnetic absorbent of Ni1-xCox micro chains that synthesized through a magnetic field-assisted reduction method. The precipitated Ni1-xCox particles could be connected and aligned during the magnetic reduction process. Due to the modified electronic structure of the Co active site by Ni, the particle size in the Ni1-xCox micro chains noticeably increases with increased x. Meanwhile, the complex dielectric constants exhibit a decreasing trend, which contributes to the improved impedance matching and higher resonance frequencies. The connected Ni1-xCox micro/nano particles not only benefit to the conductive loss, but also strengthened the polarization loss on the contacted interfaces among the particles. As a result, significantly enhanced electromagnetic wave absorption performance was obtained with the minimum reflection loss of −21.0 dB and the effective absorption bandwidth of 3.92 GHz at a thickness of only 1.35 mm. Overall, this work has demonstrated the strategy of designing aligned bimetallic absorbent, possessing great potentials in improving their microwave absorption properties.

The Identification of Faults using Magnetic Method in Kulonprogo, Yogyakarta, Indonesia

The aims of this study to identify faults and identify subsurface lithology using magnetic anomaly data in the Kulonprogo. In the acquisition was carried out using a Proton Procession Magnetometer (PPM) Geotron G5 with 62 measurement points and a distance of ±1 km between point. Measurements were made on Kebobutak (Tmok), Aluvium (Qa), Andesit (a), and Sentolo (Tmps) formations. The total magnetic field data processing is done with several correction, namely diurnal correction, IGRF, reduce to equator, upward continuation at an altitude of 2000 m, and reduce to pole, and 2D modelling using the forward modelling method. The result of the analysis obtained magnetic field anomaly values in the range of values -400 to 950 nT. The 2D modelling shows that the research area is composed of 4 dominating rock types, namely andesite rock with a susceptibility value of 94 x 10-3, andesite breccia rock with a susceptibility value of 29 x 10-3, clay rock with a susceptibility value of 0,013 x 10-3, and sandstone with a susceptibility value of 5 x 10-3. The identification result show the existence of faults line on Mount Watuaglik, Mount Kamal, and Mount Bodag.

Efficient Quantum of Mechanical Simulation of Diffusion-Weighted MRI

Modern magnetic resonance imaging (MRI) experiments require simultaneous spin and spatial dynamics treatment. This paper aims to demonstrate the possibility of simulating a large spin system for diffusion-weighted MRI experiments. The numerical simulation of diffusion MRI depends on Bloch-Torrey equations. The latter describe the behavior of spin systems under the influence of magnetic fields and diffusion processes. They are particularly relevant in magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) studies. The equations deal with uncoupled (-1/2) spins associated with three-dimensional spatial dynamics represented by diffusion and flow. The proposed method recommends using an unopened Kronecker product for evolution generators to minimize the simulation time and reduce the occupied computer memory. Two and three-dimensional diffusion-weighted magnetic resonance imaging associated with four pairs of coupled spin systems were utilized to achieve the study’s goals. Utilizing four pairs of coupled spin systems in MRI simulation enhances accuracy and realism in modeling interactions between spins, leading to improved tissue characterization and diagnostic capabilities. The obtained results were impossible using previous simulation packages. The results of the study demonstrate that the Spinach library can simulate complex spin systems with significant spatial dynamics.

Multiobjective optimization of magnetic abrasive finishing process with periodic re-distribution of magnetic abrasive particles on 17-4PH stainless steel

Magnetic abrasive finishing (MAF) exhibits considerable potential as a promising process for enhancing surface finish quality for softer as well as harder materials. This work proposes a novel approach to harness the potential of MAF for obtaining superior surface quality of precipitation-hardening martensitic steel (17-4PH steel) while performing periodic re-distribution of magnetic abrasive particles. The experiments were conducted using the Box-Behnken design of experiments and response surface methodology (RSM). RSM-based desirability function approach and genetic algorithms were used for multiobjective optimization. The set of pareto-optimal solutions obtained through multiobjective optimization were ranked using the Technique for Order of Preference by Similarity to an Ideal Solution (TOPSIS) by assigning equal importance to the selected performance parameters (percentage change in surface roughness (PCSR) and material removal rate (MRR)). The optimized values of PCSR and MRR obtained through the desirability function of RSM and genetic algorithm were validated experimentally and compared with the predicted values obtained through the regression model. Results showed that the desirability function of RSM provided better results than the genetic algorithm for the selected conditions and confirmed the effectiveness of the proposed approach.

Review on high-temperature superconducting REBCO trapped field magnets

Abstract Superconducting (SC) magnets can generate exceptionally high magnetic fields and can be employed in various applications to enhance system power density. In contrast to conventional coil-based SC magnets, high-temperature superconducting (HTS) trapped field magnets (TFMs), namely HTS trapped field bulks (TFBs) and trapped field stacks (TFSs), can eliminate the need for continuous power supply or current leads during operation and thus can function as super permanent magnets. TFMs can potentially trap very high magnetic fields, with the highest recorded trapped field reaching 17.89 T, achieved by TFSs. TFMs find application across diverse fields, including rotating machinery, magnetic bearings, energy storage flywheels, and magnetic resonance imaging (MRI). However, a systematic review of the advancement of TFMs over the last decade remains lacking, which is urgently needed by industry, especially in response to the global net zero target. This paper provides a comprehensive overview of various aspects of TFMs, including simulation methods, experimental studies, fabrication techniques, magnetisation processes, applications, and demagnetisation issues. Several respects have been elucidated in detail to enhance the understanding of TFMs, encompassing the formation of HTS bulk composites and TFSs, trapped field patterns, enhancement of trapped field strength through pulsed field magnetisation (PFM), as well as their applications such as SC rotating machines, levitation, and Halbach arrays. Challenges such as demagnetisation, mechanical failure, and thermal instability have been illuminated, along with proposed mitigation measures. The different roles of ferromagnetic materials in improving the trapped field during magnetisation and in reducing demagnetisation have also been summarised. It is believed that this review article can provide a useful reference for the theoretical analysis, manufacturing, and applications of TFMs within various domains such as materials science, power engineering, and clean energy conversion.

Effect of Na<sub>2</sub>CO<sub>3</sub> and CaCO<sub>3</sub> on deep dephosphorization by the direct reduction of high-phosphorus oolitic hematite

The direct reduction–magnetic separation process based on coal is considered to be one of the most important methods that can effectively utilize high-phosphorus oolitic hematite. In this study, the mechanism of the effects of CaCO<sub>3</sub> and Na<sub>2</sub>CO<sub>3</sub> on the dephosphorization of high-phosphorus oolitic hematite during the direct reduction process was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that Na2CO3 and CaCO3 reacted with Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> during the direct reduction process, inhibited the generation of hercunite (FeAl<sub>2</sub>O<sub>4</sub>) and fayalite (Fe<sub>2</sub>SiO<sub>4</sub>), and promoted the reduction of metallic iron (Fe). Furthermore, the reaction inhibited the reduction of apatite and prevented the generation of FeP<sub>2</sub>. Na<sub>2</sub>CO<sub>3</sub> could change the form of phosphorus in the gangue from Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> to Na<sub>2</sub>Ca<sub>4</sub>(PO<sub>4</sub>)<sub>2</sub>SiO<sub>4</sub>. Increasing the dosages of Na2CO3 and CaCO3 in the dephosphorization agent and increasing the content of Na<sub>2</sub>CO<sub>3</sub> in the dephosphorization agent were beneficial to the growth of metallic iron particles, and increasing the dosage of Na<sub>2</sub>CO<sub>3</sub>, CaCO<sub>3</sub> in the dephosphorization agent had more significant effects on metallic iron particles than increasing the content of Na<sub>2</sub>CO<sub>3</sub> in the dephosphorization agent. The research conducted in this study is expected to provide a basis for the effective exploitation of complex and refractory iron ores.

Beyond traditional magnetic resonance processing with artificial intelligence

Smart signal processing approaches using Artificial Intelligence are gaining momentum in NMR applications. In this study, we demonstrate that AI offers new opportunities beyond tasks addressed by traditional techniques. We developed and trained artificial neural networks to solve three problems that until now were deemed “impossible”: quadrature detection using only Echo (or Anti-Echo) modulation from the traditional Echo/Anti-Echo scheme; accessing uncertainty of signal intensity at each point in a spectrum processed by any given method; and defining a reference-free score for quantitative access of NMR spectrum quality. Our findings highlight the potential of AI techniques to revolutionize NMR processing and analysis.

Neural Network Architectures and Magnetic Hysteresis: Overview and Comparisons

The development of innovative materials, based on the modern technologies and processes, is the key factor to improve the energetic sustainability and reduce the environmental impact of electrical equipment. In particular, the modeling of magnetic hysteresis is crucial for the design and construction of electrical and electronic devices. In recent years, additive manufacturing techniques are playing a decisive role in the project and production of magnetic elements and circuits for applications in various engineering fields. To this aim, the use of the deep learning paradigm, integrated with the most common models of the magnetic hysteresis process, has become increasingly present in recent years. The intent of this paper is to provide the features of a wide range of deep learning tools to be applied to magnetic hysteresis context and beyond. The possibilities of building neural networks in hybrid form are innumerable, so it is not plausible to illustrate them in a single paper, but in the present context, several neural networks used in the scientific literature, integrated with various hysteretic mathematical models, including the well-known Preisach model, are compared. It is shown that this hybrid approach not only improves the modeling of hysteresis by significantly reducing computational time and efforts, but also offers new perspectives for the analysis and prediction of the behavior of magnetic materials, with significant implications for the production of advanced devices.

Current-Induced Field-Free Switching of Co/Pt Multilayer via Modulation of Interlayer Exchange Coupling and Magnetic Anisotropy.

Current-induced field-free magnetic switching using spin-orbit torque has been an important topic for decades due to both academic and industrial interest. Most research has focused on introducing symmetry breakers, such as geometrical and compositional variation, pinned layers, and symmetry-broken crystal structures, which add complexity to the magnetic structure and fabrication process. We designed a relatively simple magnetic structure, composed of a [Co/Pt] multilayer and a Co layer with perpendicular and in-plane magnetic anisotropy, respectively, with a Cu layer between them. Current-induced deterministic magnetic switching was observed in this magnetic system. The system is advantageous due to its easy control of the parameters to achieve the optimal condition for magnetic switching. The balance between magnetic anisotropic strength and interlayer coupling strength is found to provide the optimal condition. This simple design and easy adjustability open various possibilities for magnetic structures in spin-based electronics applications using spin-orbit torque.

Novel magnetic adsorbents based on oyster and clam shells for the removal of cadmium in soil

Magnetic adsorbents can effectively remove heavy metals from soil. However, the magnetization process may reduce availability of adsorption sites, making it challenging to balance magnetic and adsorption properties. In this study, oyster shell (OS) and clam shell (CS) material was magnetized by an improved chemical co-precipitation method. The organic matter in the shells was destroyed by calcination modification to expose new active sites, and calcinated ferro-magnetic adsorbent was produced with either ferrosodium EDTA (giving CEOS and CECS) or with iron citrate (for CCOS and CCCS). All four modified adsorbents reached adsorption equilibrium for Cd2+ in solution within 120 min, with maximum adsorption capacities ranging from 115.5 to 266.5 mg/g, giving high removal efficiencies for Cd2+. Adsorption by precipitation and cation exchange mechanisms was dominant, together contributing >60 % of all adsorption capacity, followed by complexation. When used for remediation of Cd-contaminated soil, CEOS demonstrated the best Cd removal efficiency, achieving removal rates of 46 % and 58 % for total and available Cd, respectively. This was mainly because CEOS had the highest magnetic recovery rate, of 98 %. CEOS maintained removal rates of 34 % for total Cd after regeneration and reuse three cycles, with recovery rates remaining above 90 %. Contaminated soil was treated with the novel adsorbents and in pot experiments with water spinach cultivation it was shown that both CEOS and CECS treatment significantly reduced Cd content (by up to 56 %). The magnetic adsorbents presented here demonstrate excellent performance to remove Cd from water and soil, and have promising application prospects.

A Bio-Inspired Magnetic Soft Robotic Fish for Efficient Solar-Energy Driven Water Purification.

Solar-driven water evaporation is a promising solution for global water scarcity but is still facing challenges due to its substantial energy requirements. Here, a magnetic soft robotic bionic fish is developed by combining magnetic nanoparticles (Fe3O4), poly(N-isopropylacrylamide), and carboxymethyl chitosan. This bionic fish can release liquid water through hydrophilic/hydrophobic phase transition and dramatically reduce energy consumption. The introduced Fe3O4 nanoparticles endow the bionic fish with magnetic actuation capability, allowing for remote operation and recovery. Additionally, the magnetic actuation process accelerates the water absorption rate of the bionic fish as confirmed by the finite element simulations. The results demonstrate that bionic fish can effectively remove not only organic molecular dyes dissolved in water but also harmful microbes and insoluble microparticles from natural lakes. Moreover, the bionic fish maintains a good purification efficiency even after five recycling cycles. Furthermore, the bionic fish possesses other functions, such as salt purification and salt rejection. Finally, the mechanism of water purification is explained in conjunction with molecular dynamics calculations. This work provides a new approach for efficient solar-energy water purification by phase transition behavior in soft robotics.