Magnetic Parameters Research Articles

Static magnetic fields in regenerative medicine.

All organisms on Earth live in the weak but ubiquitous geomagnetic field. Human beings are also exposed to magnetic fields generated by multiple sources, ranging from permanent magnets to magnetic resonance imaging (MRI) in hospitals. It has been shown that different magnetic fields can generate various effects on different tissues and cells. Among them, stem cells appear to be one of the most sensitive cell types to magnetic fields, which are the fundamental units of regenerative therapies. In this review, we focus on the bioeffects of static magnetic fields (SMFs), which are related to regenerative medicine. Most reports in the literature focus on the influence of SMF on bone regeneration, wound healing, and stem cell production. Multiple aspects of the cellular events, including gene expression, cell signaling pathways, reactive oxygen species, inflammation, and cytoskeleton, have been shown to be affected by SMFs. Although no consensus yet, current evidence indicates that moderate and high SMFs could serve as a promising physical tool to promote bone regeneration, wound healing, neural differentiation, and dental regeneration. All in vivo studies of SMFs on bone regeneration and wound healing have shown beneficial effects, which unravel the great potential of SMFs in these aspects. More mechanistic studies, magnetic field parameter optimization, and clinical investigations on human bodies will be imperative for the successful clinical applications of SMFs in regenerative medicine.

La3+ substitution-adjusted magnetic and optical properties with enhanced photocatalytic activity and stability of copper zinc nickel ferrites for wastewater treatment applications

Copper-zinc-nickel (Cu–Zn–Ni) ferrite nanoparticles are used for wastewater treatment technology. However, low degradation efficiency and stability are two main issues that make them unsuitable for actual production needs. In this paper, the citrate-nitrate auto-combustion method was applied for the formation of Cu0.5Zn0.25Ni0.25LaxFe2–xO4; (0≤x≤0.1; step 0.02) (CZNL) nanoferrites. Although the substitution process entails the replacement of a small ion with a larger one, the lattice constant and crystallite size does not exhibit a consistent incremental pattern. This behavior is justified and discussed. The size of all the CZNL ferrite nanoparticles is in the range of 8–12 nm, and the lattice constant is in the range of 8.6230 to 8.4865 nm. The morphological analysis conducted using field emission-scanning electron microscopy (FE-SEM) reveals that the CZNL exhibits agglomerated spherical morphology. The energy dispersive X-ray spectrameter (EDAX) analysis was employed to confirm the elemental composition of CZNL nanoferrites. Since the process entails the substitution of Fe3+ magnetic ions with non-magnetic ions La3+, the magnetic parameters of CZNL nanoferrites show a general decreasing trend as predicted. At 20 K, saturation magnetization Ms shows an overall drop in its values from 59.302 emu/g at x = 0.0–41.295 emu/g at x = 0.1, the smallest value of 37.87 emu/g is recorded at x = 0.06. the highest coercivity (Hc = 125.9 Oe) and remanence (Mr = 13.32 emu/g) are recorded for x = 0.08 and x = 0.04 nanoferrite, respectvely. The band gap of all the CZNL nanoferrites was determined using the Kubelka–Munk function and Tauc plot for direct permitted transitions. La doping modifies the band gap (within 1.86–1.75 eV), increases light absorption, induces efficient e/h separation and charge migration to Cu0.5Zn0.25Ni0.25LaxFe2–xO4 surfaces. The nanoferrite Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 achieves a degradation efficiency of 97.3% for methylene blue (MB) dye removal after just 60 min. After five recycling processes, the nanocatalyst Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 is degraded by 95.83%, resulting in a negligible 1.51% decrease in photocatalytic activity efficiency. The new Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 has exceptional photocatalytic activity and remarkable stability, making it a promising candidate for applications in wastewater treatment.

Influence of Soret–Dufour on a magneto‐micropolar fluid over a porous stretching surface with a nonuniform heat source/sink

AbstractThe goal of the current investigation is to ascertain the influence of Soret and Dufour on a magneto‐micropolar fluid past a permeable stretching surface with a nonuniform heat source/sink. Moreover, the investigation considers the influence of melting heat transfer, as well as the implications of velocity, thermal, and solutal slips. Numerical solutions to the basic governing equations are achieved using the Runge–Kutta–Fehlberg technique. The analysis of our results reveals several important findings. Enhancing the material parameter leads to an upsurge in the velocity profile, whereas the opposite trend exists for the boosting estimations of the magnetic parameter. Enhancing the Soret parameter leads to an improvement in the concentration profile while improving the Dufour factor results in an enhancement in the temperature distribution. These findings are critical for understanding the heat transfer over a stretching sheet, subject to different models and they encompass aspects such as temperature distribution, heat transfer rates, boundary layer characteristics, velocity profiles, and the potential for implementing heat transfer enhancement techniques. The findings of this current investigation are consistent with those that have been previously reported. Fluid dynamics, materials processing, cooling systems, and thermal systems are just a few of the real‐life domains that can benefit from understanding magneto‐micropolar fluid flow over a porous stretching surface with a nonuniform heat source–sink and incorporating Soret and Dufour effects.

Unsteady dynamical analysis of convective hydromagnetic thermal migration of chemically reacting tiny species with dissipation and radiation in an inclined porous plate

The essence of the current examination is to carry out thermofluid parametric sensitivity with time-varying thermal migration of chemically reactive tiny species across an oscillating infinite plate surface. The impact of thermal motile tiny particles under the influence of many other oscillating flow parameters has yet to be investigated; hence the results obtained in this research are novel. Using a suitable non-dimensional variable, the leading PDEs (partial differential equations) are transmuted into dimensionless PDEs, ensuring equations are numerically solved using the MAPLE built-in approach. The numerical values produced in a limited scenario are linked with the outcomes found in the literature to validate the precision of the numerical approach utilized. The fluctuations in the profiles of the velocity, temperature, and concentration, in addition to the wall friction and rate of thermal and solutal transport, are illustrated via graphs and tables due to the modification of the critical parameters. The endmost results of the study concede that increasing permeability quantity and thermal and solutal buoyancy impellers intensify the fluid velocity. In contrast, a converse tendency is perceived with magnetic parameter and also, wall friction acts opposite to the velocity. The fluid temperature attenuated with dilation of the Prandtl number and radiation parameter, whilst a contrary trend was perceived with Eckert number. The increasing thermo-diffusion helps to develop fluid concentration whilst the Schmidt number and chemical reaction displayed opposite trend. Further, we achieved a tremendous conformity between the current findings and genuine results in the literature.

Electrospun Cu-Co ferrite nanofibers: synthesis, structure, optical and magnetic properties, and anti-cancer activity.

In this study, we investigated Cu-Co ferrite nanofibers (NFs) that were synthesized for the first time employing the electrospinning technique. The structure, phase purity and crystallite size of all the prepared NFs were revealed by powder X-ray diffraction (PXRD) analysis. The NFs crystallized in the Fd3̄m (no. 227) space group and the cation distribution arrangement over distinct sites in their structure was analyzed. Scanning electron microscopy (SEM) together with energy-dispersive X-ray (EDX) spectroscopy analysis showed the microstructure of the NFs and verified their expected chemical compositions. High-resolution transmission electron microscopy (TEM) images confirmed the fibrous nature and the construction of the NFs. The band gap energies derived from the UV-vis reflectance spectra showed a blue shift with an increase in the amount of Cu in the sample from 1.42 eV to 1.86 eV. Magnetization (M) as a function of magnetic field (H) measurements performed at ambient and low temperatures showed the ferrimagnetic behavior of all the NFs. The magnetic parameters including coercivity (Hc), saturation magnetization (Ms), remanent magnetization (Mr), and squareness ratio were determined from the recorded magnetization curves. At 300 K, Ms was reduced from 78.8 to 42.4 emu g-1, Mr reduced from 22.8 to 7.6 emu g-1 and the Bohr magneton reduced from 3.3 to 1.8μB with an increase in the content of Cu in the samples. The same trend was observed at 10 K, where Ms was reduced from 93.7 to 50.9 emu g-1, Mr reduced from 60.9 to 35.9 emu g-1 and the Bohr magneton reduced from 3.94 to 2.16μB. Alternatively, Hc has the highest values for x = 0 (850 Oe at 300 K and 5220 Oe at 10 K) and x = 0.6 (800 Oe at 300 K and 5400 Oe at 10 K). The anti-cancer activity of the NFs was evaluated using the MTT cell viability assay, showing a reduction in the viability of both HCT-116 and HeLa cancer cells compared to non-cancerous HEK-293 cells after treatment with the NFs. Apoptotic activity was examined by DAPI staining, where treatment with the NFs induced chromatin condensation and nuclear disintegration in HCT-116 cells.

Evaluation of the Embrittlement in Reactor Pressure-Vessel Steels Using a Hybrid Nondestructive Electromagnetic Testing and Evaluation Approach.

The nondestructive determination of the neutron-irradiation-induced embrittlement of nuclear reactor pressure-vessel steel is a very important and recent problem. Within the scope of the so-called NOMAD project funded by the Euratom research and training program, novel nondestructive electromagnetic testing and evaluation (NDE) methods were applied to the inspection of irradiated reactor pressure-vessel steel. In this review, the most important results of this project are summarized. Different methods were used and compared with each other. The measurement results were compared with the destructively determined ductile-to-brittle transition temperature (DBTT) values. Three magnetic methods, 3MA (micromagnetic, multiparameter, microstructure and stress analysis), MAT (magnetic adaptive testing), and Barkhausen noise technique (MBN), were found to be the most promising techniques. The results of these methods were in good agreement with each other. A good correlation was found between the magnetic parameters and the DBTT values. The basic idea of the NOMAD project is to use a multi-method/multi-parameter approach and to focus on the synergies that allow us to recognize the side effects, therefore suppressing them at the same time. Different types of machine-learning (ML) algorithms were tested in a competitive manner, and their performances were evaluated. The important outcome of the ML technique is that not only one but several different ML techniques could reach the required precision and reliability, i.e., keeping the DBTT prediction error lower than a ±25 °C threshold, which was previously not possible for any of the NDE methods as single entities. A calibration/training procedure was carried out on the merged outcome of the testing methods with excellent results to predict the transition temperature, yield strength, and mechanical hardness for all investigated materials. Our results, achieved within the NOMAD project, can be useful for the future potential introduction of this (and, in general, any) nondestructive evolution method.

Significance of hafnium nanoparticles in hydromagnetic non-Newtonian fluid-particle suspension model through divergent channel with uniform heat source: thermal analysis

Abstract This theoretical analysis provided the exact solution of a steady flow of Casson rheological fluid in fluid-particle suspension models through a divergent channel with consideration of porous medium, electric, and magnetic fields, and slip boundary conditions. The thermal transport analysis is also observed with the consideration of viscous dissipation and uniform heat source. The suitable transformation is used to reduce the partial differential equation into ordinary differential equations and obtain the exact solution by adopting the mathematical software MATHEMATICA 12.0. The momentum and thermal profiles are decreasing functions of the magnetic field parameter. The number of streamlines is increased and covers more parts of the channel for increasing the Darcy force and velocity slip parameters. The computational results of this study will help to understand the momentum and thermal analysis in the fluid-particle suspension model. The results of the current study are useful to increase the oil recovery system, in thermal transport energy, energy production, cooling and heating systems, etc. The current model can be useful in renewable energy to store thermal energy by using the hafnium nanoparticles. The present analysis is original and has not been submitted nor published before.

Morphological and Quantitative Parametric MRI Follow-up of Cartilage Changes Before and After Intra-articular Injection Therapy in Patients With Mild to Moderate Knee Osteoarthritis: A Randomized, Placebo-Controlled Trial.

Intra-articular injections are routinely used for conservative treatment of knee osteoarthritis (OA). The detailed comparative therapeutic effects of these injections on cartilage tissue are still unclear. The aim of this study was to detect and compare knee cartilage changes after intra-articular injection of glucocorticoid, hyaluronic acid, or platelet-rich plasma (PRP) to placebo using quantitative (T2 and T2* mapping) and morphological magnetic resonance imaging parameters in patients with mild or moderate osteoarthritis. In a double-blinded, placebo-controlled, single-center trial, knees with mild or moderate osteoarthritis (Kellgren-Lawrence grade 1-3) were randomly assigned to an intra-articular injection with 1 of these substances: glucocorticoid, hyaluronic acid, PRP, or placebo. Cartilage degeneration on baseline and follow-up magnetic resonance imaging scans (after 3 and 12 months) was assessed by 2 readers using quantitative T2 and T2* times (milliseconds) and morphological parameters (modified Outerbridge grading, subchondral bone marrow edema, subchondral cysts, osteophytes). One hundred twenty knees (30 knees per treatment group) were analyzed with a median patient age of 60 years (interquartile range, 54.0-68.0 years). Interreader reliability was good for T2 (ICC, 0.76; IQR, 0.68-0.83) and T2* (ICC, 0.83; IQR, 0.76-0.88) measurements. Morphological parameters showed no significant changes between all groups after 3 and 12 months. T2 mapping after 12 months showed the following significant ( P = 0.001-0.03) changes between groups in 6 of 14 compartments: values after PRP injection decreased compared with glucocorticoid in 4 compartments (complete medial femoral condyle and central part of lateral condyle) and compared with placebo in 2 compartments (anterior and central part of medial tibial plateau); values after glucocorticoid injection decreased compared with placebo in 1 compartment (central part of medial tibial plateau). No significant changes were seen for T2 and T2* times after 3 months and T2* times after 12 months. No correlation was found between T2/T2* times and Kellgren-Lawrence grade, age, body mass index, or pain (Spearman ρ, -0.23 to 0.18). Platelet-rich plasma injection has a positive long-term effect on cartilage quality in the medial femoral compartment compared to glucocorticoid, resulting in significantly improved T2 values after 12 months. For morphological cartilage parameters, injections with glucocorticoid, PRP, or hyaluronic acid showed no better effect in the short or long term compared with placebo.

Mixed Ba-hexaferrite: An experimental investigation of thermal, structural, morphological, and magnetic properties of hexa-phasic magnetocomposite and its constituting phases

Magnetocomposite materials have expanded their attention in recent years due to the focused and continuously growing applicability of these nanostructured materials. The successful outcomes of blending several magnetic phases may offer the development of a surprisingly new magnetic phenomenon or superior magnetic performance than conventional magnetic materials. This research work involves the synthesis of six types of barium hexaferrite (BaHF) phases, i.e., Y, M, W, X, U, Z-type, along with mixed Ba-hexaferrite (blending all six phases) and its thorough investigation of magnetic characteristics with a wide range of temperatures (2 K–900 K). The insightful and comparative understanding of the thermal reactions during phase formation within all six phases is explained by determining kinetic parameters. The magnetic parameters concerning each barium hexaferrite phase are explained by the structural and morphological constraints. The sintered mixed Ba-hexaferrite consists of a room temperature ferrimagnetic behavior (Ms = 74.85 emu/g, Hc = 45.35 Oe) and exhibits a deviation from its theoretical values (using Vegard's law), revealing the presence of interphasic interaction within it. The low-temperature spin dynamics confirm the existence of a spin-glass state at 110 K, including a broader magnetic susceptibility response starting at 185 K, associated with the evolution of a reentrant spin-glass state.

Numerical thermal investigation of radiative magnetohydrodynamics axisymmetric Cu-Al2O3/H2O hybrid nanofluid flow over an unsteady radially stretched surface

The current work focuses on conducting a numerical thermal investigation of nanofluid and hybrid nanofluid flow over unsteady radial stretching surfaces. To perform a comprehensive analysis, lamina and hexahedron-shaped Aluminum Oxide (Al2O3) and Copper (Cu) nanomaterial are immersed in water-based fluid. Furthermore, we take into account the impact of magnetohydrodynamics (MHD) and thermal radiation. The cylindrical coordinate system is utilised for mathematical modeling. The governing system of nonlinear PDEs is converted to a system of ODEs by utilising appropriate similarity transformation and then solved numerically in MATLAB. By using graphs and bar charts, we visually depict the impact of significant physical attributes on velocity, temperature, skin friction, and Nusselt numbers. As per the findings, The nanofluid and hybrid nanofluid flow experienced a notable deceleration due to the influence of the suction parameter (S), unsteadiness parameter (A), and magnetic parameter (M). Furthermore, hybrid nanofluid exhibits the lowest temperature and the slowest velocity. In the case of nanofluid composed of Aluminum Oxide (Al2O3) and water (H2O), the highest Nusselt number is observed along with the lowest skin friction. These recent findings hold the potential to offer advantages to academic research, lubrication processes, and the polymer industry. Abbreviations: PDE’s Partial Differential Equation; ODE’s Ordinary Differential Equation; MHD Magnetohydrodynamic

Emergence of the isotropic Kitaev honeycomb lattice α− RuCl3 and its magnetic properties

We present a comprehensive investigation of the crystal and magnetic structures of the van der Waals antiferromagnet α− RuCl3 using single crystal x-ray and neutron diffraction. The crystal structure at room temperature is a monoclinic ( C2/m ). However, with decreasing temperature, a remarkable first-order structural phase transition is observed, leading to the emergence of a rhombohedral ( R3ˉ ) structure characterized by three-fold rotational symmetry forming an isotropic honeycomb lattice. On further cooling, a zigzag-type antiferromagnetic order develops below TN=6∼6.6 K. The critical exponent of the magnetic order parameter was determined to be β=0.11(1) , which is close to the two-dimensional Ising model. Additionally, the angular dependence of the magnetic critical field of the zigzag antiferromagnetic order for the polarized ferromagnetic phase reveals a six-fold rotational symmetry within the ab− plane. These findingsreflect the symmetry associated with the Ising-like bond-dependent Kitaev spin interactions and underscore the universality of the Kitaev interaction-dominated antiferromagnetic system.

Influence of inclined magnetic field and heat transfer on the peristaltic flow of Rabinowitsch fluid model in an inclined channel

The recent study is focused on discussion of heat transfer and magnetic field results of peristaltic flow of Rabinowitsch fluid model in an Inclined Channel. In this piece of research, peristalsis’s fundamental problem with heat transfer in the presence of a magnetic field is checked. An incompressible Rabinowitsch fluid is present in an inclined channel, which is considered as the reference for this research. The solutions are devised with the assumptions of long wavelength and low Reynolds number approximations. The resulting equations are then solved exactly by implementing various command of MATHEMATICA subject to relevant boundary conditions. Results are discussed for various flow quantities like temperature, velocity, tangential stress, pressure gradient and rise, and friction force. Computational simulations are performed to determine the flow quantities. This investigation goes beyond mere calculations and examines particle motion to gain deeper insights into flow quantities. Furthermore, this investigates how magnetic field and heat transfer parameters influence these peristaltic flow phenomena. The outcomes of important parameters were plotted and scrutinized. There is amultitude of medical implementations derived from the current consideration, such as the depiction of the gastric juice motion in the small intestine when an endoscope is inserted through it.

Numerical simulation of magneto-hydrodynamic fluid flow with heat sink, chemical diffusion and Powell Eyring fluid behavior using Cattaneo–Christov source term

The aim of this study is to investigate the impact of magneto hydrodynamic Powell–Eyring fluid on double-diffusive phenomena, with a specific focus on employing the Cattaneo–Christov model. The purpose is to enhance the study's scope by incorporating a heat sink and chemical reactions, thereby analyzing the intricate interplay between heat transfer and chemical processes within the MHD fluid system. To achieve this aim, the study utilizes similarity variables to convert PDEs into ODEs. The primary objective is to gain insights into mass and heat transmission dynamics, placing a particular emphasis on understanding the influence of chemical reactions in the system. For numerical solutions during the analysis, MATLAB's BVP4C solver and the shooting technique are employed. The research further aims to explore various physical constraints, including the fluid Nusselt number and skin friction coefficient. By doing so, the study provides a comprehensive understanding of how the MHD fluid system responds to different conditions. The notable outcomes, presented through graphical representations and tables, include a discernible decrease in fluid velocity with a higher magnetic field parameter and an observable increase in fluid temperature with greater heat source constraints. In summary, this exploration subsidizes significantly to our considerate of complex fluid behavior and holds practical applicability in various scientific and engineering contexts. The novel and physical insights from the study offer valuable understanding into the impact of magneto hydrodynamic Powell–Eyring fluid, particularly concerning double-diffusive phenomena and the intricate interplay between heat transfer and chemical processes.

Ab Initio Investigation of the Structural, Elastic, Dynamic, Electronic, and Magnetic Properties of Cubic Perovskite CeCrO3.

We presented the results of various aspects related to structural, elastic, electronic, dynamic, and magnetic parameters of cubic perovskite CeCrO3 by means of the full-potential linearized augmented plane wave (FP-LAPW) approach. The calculation of the unit cell volume against the total energy curve confirms that CeCrO3 exhibits higher energetic stability in the ferromagnetic (FM) order. Calculated structural aspects at equilibrium demonstrate excellent similarity to present information, lending credibility to our results. Moreover, monocrystalline elastic constants have been analyzed numerically. These constants provide insights into several related properties, including elastic anisotropy, mechanical stability, and several polycrystalline elastic aspects. Furthermore, the phonon dispersion curves obtained from our calculations reveal the existence of soft modes, which suggests the potential metastability of CeCrO3. Through an analysis of the energy band dispersions, the half-metallic nature of this material is confirmed, such as Eg = 3.00 and 3.13 eV for the HM state within generalized gradient approximations Perdew-Burke-Ernzerhof (GGA-PBE) and Tran-Blaha modified Becke-Johnson (TB-mBJ) calculations, respectively, as well as the FM total magnetic moment of 4.000 μB. Partial density of states (PDOS) aided in identifying the electronic states that contribute to the energy bands. Finally, the computed total magnetic moment aligns fit the theoretical findings available in the literature.

The effects of magnetic field and thermal radiation on the mixed convection of Al2O3-Cu/water hybrid nanofluid over a permeable vertical flat plate

This study comprehensively investigates the effect of magnetic fields and thermal radiation on mixed convection in a hybrid alumina–copper/water nanofluid flowing over a permeable vertical flat plate. The study aims to model conventional nanofluid behavior accurately by considering the hybridization of two types of nanoparticles. Conventional similarity transformations and Akbari–Ganji’s method are employed to simplify the governing equations, resulting in ordinary differential equations. Among the dual solutions obtained, only one stable solution is identified. The key findings reveal that boundary layer separation can be avoided by reducing the copper concentration volume and increasing the magnetic and radiation parameters. The mixed convection parameters induce counter-flow, enhancing heat transfer when the magnetic and radiation parameters increase and the copper concentration volume decreases. Conversely, increasing the concentration volume of copper leads to accelerated boundary layer separation and reduced measured physical quantities. Overall, the mixed convection parameter enhances skin friction and heat transfer rates, particularly in the achievable solution. The accuracy of the proposed method is validated through a comparison with the finite element method (FEM). The graphical presentation of the results facilitates a clearer interpretation of the study’s findings.

Gathering Evidence to Leverage Musculoskeletal Magnetic Stimulation Towards Clinical Applicability

Musculoskeletal disorders are among the main causes of disease‐associated disability. Moreover, the incidence and prevalence of osteoporosis and osteoarthritis, as well as the risk of bone fractures and the need for joint replacements, are expected to increase with longer life expectancy. New approaches based on electromagnetic stimulation have been developed, aiming to shorten bone healing time, attenuate osteoporosis and osteoarthritis, and increase implants' osseointegration. Inductive coupling (IC), a non‐invasive methodology to deliver magnetic stimuli, has reached clinical trials and some clinical practices but is not yet considered a standard procedure. Indeed, its feasibility in clinical use is still under discussion, and optimal stimulation parameters are fairly undefined. This comprehensive review describes the research trends and applicability of IC‐based therapeutics for musculoskeletal disorders, and starts identifying top‐performing magnetic stimulation parameters. Insights into the magnetic stimuli setups that promote osteogenesis are provided, based on pre‐clinical and clinical evidence from 117 in vivo studies in animal models and human patients. Potential cellular and molecular biomechanisms mediating IC‐induced effects on osteoblasts and osteoclasts are also explored. The transversal knowledge herein delivered will hopefully support innovative designs and medical devices that will implement IC stimulation as a clinical standard and effective therapeutic for musculoskeletal disorders.

Dual solutions of Darcy-Forchheimer radiative-convective magneto-nanofluid flow over an exponentially stretching/shrinking surface: Stability and entropy generation analysis

A numerical investigation was conducted to examine the existence of dual solutions over exponentially stretching or shrinking permeable surfaces. The study aimed to analyze the impact of thermal and second-order velocity slip on magnetohydrodynamic (MHD) mixed convective radiative nanofluid flow within a Darcy-Forchheimer porous medium while considering heat generation. Two distinct types of nanofluids, namely Cu-water and TiO 2/water, were employed in the investigation. To address the nonlinear partial differential equations (PDEs), similarity transformations were utilized to transform them into a system of ordinary differential equations (ODEs). The resulting coupled higher-order nonlinear ODEs were then solved using a MATLAB-based boundary value algorithm known as bvp4c. Two distinct solutions are observed within a restricted range of the stretching/shrinking parameter ξ ( ξ > ξ c ) and suction parameter S ( S > S c ), terminating respectively at ξ = ξ c or S = S c . The critical values are identified as ξ c = − 1.1952 ( Cu − water ) , − 0.9304 ( Ti O 2 − water ) and S c = 1.6437 ( Cu − water ) , 1.8900 ( Ti O 2 − water ) , maintaining the fixed values of the remaining physical parameters. Notably, the critical value for Cu-water is lower than that of TiO 2-water. Moreover, in both solution branches, the range of skin-friction coefficient and local Nusselt number for Cu-water surpasses that of TiO 2-water. An evaluation of the temporal stability of these solutions reveals that only the first solution remains stable. This is supported by the positivity of the smallest eigenvalues ( γ 1 > 0 ), indicating stability. Conversely, for the second solution, the smallest eigenvalues ( γ 1 < 0 ) are negative, signifying its instability. Also, Cu-water nanofluid exhibits higher fluid velocity and lower fluid temperature than TiO 2-water nanofluid for stable solutions and the opposite behavior for unstable solution branches. Significantly, within the initial solution branch, there is an escalation in velocity profiles attributed to the magnetic parameter, Grashof number, porous parameter, and first- and second-order velocity slip parameter. Conversely, a decrease is observed for the Forchheimer number, while the opposite holds true for the second solution branch. For both solution branches, the temperature profiles experience a reduction due to thermal slip and stretching/shrinking parameters, whereas enhancements are noted for thermal radiation and heat generation parameters. Furthermore, an increase in the suction parameter leads to elevated skin friction coefficient and local Nusselt number in the first stable solution, thereby promptly improving heat transfer efficiency. Moreover, improvements in entropy generation arise from factors such as thermal radiation, magnetic field, and nanoparticle solid volume fraction, presenting opportunities to optimize heat transmission in cooling and heating systems.

Magnetic micro-archaeology: a method for conducting rock magnetic microfacies analysis on archaeological soil micromorphology samples, with a case study from El Salt, Alcoy, Spain

For geoarchaeologists the use of multiproxy and multimethod integrative approaches has become common for studying the sedimentary context of archaeological materials. In this paper, we introduce a novel approach that combines rock magnetic analysis with micromorphological analysis. We first conduct a brief examination of the magnetic properties of organic resins used in micromorphology to understand the potential impact of the resin and manufacturing process on the magnetic signature. It is crucial to understand the original production of the samples to ensure that endothermic reactions do not compromise the magnetic data. We illustrate the advantages of this approach through a case study of a pit hearth from the Neanderthal archaeological site of El Salt in Alcoi, Spain. This study utilises archived micromorphological samples of a pit hearth (combustion structure H77) initially described by Leierer et al. (J Archaeol Sci 123:105237, 2020). Rock magnetic analysis of multiple magnetic parameters—including magnetic susceptibility, natural remanent magnetization, and progressive isothermal remanent magnetization—reveals that each microfacies type exhibits a unique magnetic pattern, even if there is overlapping in signatures across some magnetic parameters. The interpretation of the magnetic data aligns with the results and microfacies descriptions previously provided by Leierer et al. (J Archaeol Sci 123:105237, 2020), further supporting the interpretation of the combustion feature as being in situ with a history of repeated use. The approach presented here offers an enhanced tool for micromorphologists to better understand the magnetic characteristics of microfacies units in higher resolution and establish direct connections to the micromorphological results.

Simultaneous effects of the position dependent mass and magnetic field on quantum well with the improved Tietz potential

In this study, we explored the synergistic impact of position-dependent mass and magnetic field on the electronic and optical properties of quantum wells, featuring an enhanced Tietz potential confinement incorporating both standard Morse and improved Rosen–Morse potentials, as influenced by variations in the structural parameter. Calculations were conducted within the framework of effective mass and parabolic band approximations. The diagonalization method was employed, selecting a wave function basis of trigonometric orthonormal functions to determine the eigenvalues and eigenfunctions of the confined electron potential. Our findings reveal that alterations in the sizes and shapes of the quantum wells, magnetic field strength, geometric asymmetry, and confinement parameters lead to significant variations in electron energies, transition between electron states, and the absorption spectrum. These outcomes offer valuable insights for investigating the electronic and structural properties of materials and devising novel materials with tailored optical characteristics.

Heat transfer analysis of MHD oscillatory SWCNT/MWCNT‐H2O hybrid nanofluid flow in a channel

AbstractRegulating the thermal conductivity of the fluid in various heat exchange systems plays an important role. In this regard, the carbon nanotubes (CNTs), with their higher thermal conductivity, can enhance the heat transfer potential. The main objective of the present study is to explore the impact of suction and injection on the oscillatory flow of CNT‐based hybrid nanofluid through a channel under the influence of the magnetic field for analysing heat transfer perspectives. While developing a mathematical model of the problem, we also considered other relevant elements, such as thermal radiation for optically thin fluids and porous mediums. The behaviour of a water‐SWCNT + MWCNT hybrid nanofluid is studied concerning the volume fraction of CNTs. The governing flow equations have been solved to obtain the correct solutions for the distribution of velocities and temperatures. Graphs and tables are used to assess the impact of relevant parameters on the flow and derived quantities. Adding CNTs to a fluid reduces its temperature and velocity, making it ideal for cooling systems. However, plates exhibit a maximum heat transfer of 35.35% and 25.35%, respectively, for and . The magnetic and constant pressure parameters greatly diminish the fluid's velocity, while the thermal buoyancy forces strengthen the flow. The effectiveness of the current study is confirmed by comparing its results to those from previous investigations.