Search Results (16,182)

This research analyzes the wavy, axisymmetric flow of a Ree–Eyring non-Newtonian nanofluid, infused with motile microorganisms, within a porous, tapered cylindrical channel under a transverse magnetic field. This investigation presents a theoretical framework that may inform the improvement of energy efficiency and thermal management in biomedical engineering applications, such as drug delivery systems and microfluidic biosensors. The work provides an extended insight by a contribution to the evaluation of entropy generation, explicitly considering the influence of motile microorganisms, thereby bridging a gap in the existing literature. The comprehensive physical model further incorporates the combined effects of Joule heating, viscous dissipation, nonlinear thermal radiation, and chemical reactions. Methodologically, the governing nonlinear equations of the system were rendered tractable under long-wavelength and low-Reynolds-number assumptions and subsequently solved using the numerical Runge–Kutta–Fehlberg technique. The key conclusion is that, based on the present numerical model, careful selection of magnetic field strength and microorganism motility parameters may reduce irreversible energy losses, potentially improving the net usable work in advanced nanofluid transport systems for biomedical applications, subject to experimental validation. The most significant finding reveals that the magnetic field serves as a dual-purpose control parameter: increasing its strength boosts total entropy generation by 20–30% while simultaneously raising the Bejan number, confirming heat transfer as the dominant irreversibility mechanism in the system. Additionally, nanoparticle concentration diminishes substantially with elevated chemical reaction rates and Schmidt numbers, while microorganism density is highly sensitive to the Péclet number, which causes flow disruptions. Full article

This study investigated the covalent grafting of ferulic acid (FA) onto high-amylose corn starch (HACS) through controlled moist heat treatment as a strategy to regulate starch structure and digestibility. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR) analyses confirmed the formation of ester linkages between HACS and FA. Scanning electron microscopy (SEM) revealed that FA grafting induced a rougher granule surface and increased porosity, while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated altered gelatinization behavior and thermal stability. In vitro digestion analysis showed that the rapidly digestible starch content decreased from 23% to 15%, whereas the resistant starch (RS) content increased to 48% after FA grafting. Molecular docking suggested that FA could interact with α-amylase and that covalent modification may reduce enzyme accessibility to starch chains, thereby limiting starch hydrolysis. These findings demonstrate that FA grafting effectively reshapes the structural and digestive properties of HACS and provides a promising approach for developing resistant starch-rich functional food ingredients. Full article

Melancholia remains a severe and complex form of depression. One possible avenue to a better understanding of melancholia and potentially improved methods of treating it, is via examination of the profiles of brain electrical activity of patients suffering from melancholia. However, apart from work using fMRI, relatively little is known about the electrophysiological basis of melancholia despite the potential for this to inform targeted effective treatments such as Transcranial Magnetic Stimulation. To better understand the state of research regarding EEG variables and melancholia, a systematic review was undertaken. Results indicated that there was a large degree of complexity in the association between melancholia and various EEG parameters, and that many specific aspects of brain electrical activity remain under-studied. Suggestions are made for future research. Full article

Calcium leaching increases the hydraulic concrete material’s porosity and the diffusion coefficient, thereby jeopardizing engineering safety. Fly ash and silica fume are commonly used mineral admixtures in hydraulic concrete, and their effects on the material’s leaching characteristics, especially its microstructural and transport properties, require further investigation. In this study, calcium leaching tests were conducted on cement paste (CP), silica fume–cement paste (SF), and fly ash–cement paste (FA) using a 6 mol/L ammonium chloride solution to accelerate the leaching process. Subsequently, a series of quantitative and qualitative analyses was performed on the deteriorated specimens, including phenolphthalein indicator spraying, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). Additionally, the diffusion coefficients of the material at different locations were calculated and analyzed. The results show that partially replacing cement with silica fume or fly ash increases the initial porosity, gel pore content, and initial diffusion coefficients. After 28 days of leaching, compared to the initial values, the porosity increases in the 0–4 mm layer from the leached surface were 83.6% for CP, 11.0% for SF, and 39.0% for FA. The diffusion coefficients increased by factors of 14.3 (CP), 6.1 (SF), and 13.6 (FA), indicating enhanced resistance to leaching. The primary reason for this is that the reactive silica in the admixtures undergoes a pozzolanic reaction with the calcium hydroxide generated by cement hydration, producing additional calcium silicate hydrate (C-S-H) gel, which reduces the capillary pores that would otherwise result from calcium hydroxide decomposition. Full article

Melittin (Mel) is a membrane-active peptide with potential anticancer activity, but its direct therapeutic application may be limited by nonspecific toxicity and delivery-related challenges. The study aimed to assess melittin-functionalized magnetic nanoparticles (MNPs-Mel) as a strategy to enhance antitumor activity in Caco-2 cells, with/without magnetic hyperthermia (MH) association. BJ fibroblasts were used as a normal human in vitro cellular model. The effects of free Mel (2.5 µg/mL), MNPs, and MNPs-Mel (50 µg/mL both) + MH (30 min at 355 kHz and 25 kA/m) were assessed using colorimetry (for viability), luminescence (ATP), and spectrophotometry (lactate) following different exposure conditions. The mechanism of apoptosis induction was evaluated by ELISA (caspase 8 and 9 levels). Transmission electron microscopy (TEM) was also used to evaluate nanoparticle morphology and treatment-associated cellular ultrastructural changes. Free Mel reduced viability in both cell lines, with Caco-2 cells showing greater sensitivity at lower concentrations. MNPs (with/without MH) produced limited and less consistent effects, whereas MNPs-Mel significantly reduced Caco-2 viability and ATP levels and increased LDH and caspase 9. MH further enhanced the effects of MNPs-Mel: reduced viability (57–58% of the control at 24 h and 72 h), decreased ATP levels (67% of the control at 24 h and 53% at 72 h), increased LDH levels (206% of the control at 24 h and 301% at 72 h), and induced the mitochondrial apoptotic pathway (caspase 9 increased with 2164% of the control at 72 h). TEM proved the internalization of both MNPs and MNPs-Mel and revealed extensive ultrastructural alterations concerning mitochondria and lysosomes produced by MNPs-Mel, particularly in the Caco-2 cells. These modifications were heavily increased by MNPs-Mel + MH exposure. Overall, these findings demonstrate that Mel functionalization increases the antitumor activity of Mel at lower doses and that MH further potentiates this effect in Caco-2 cells. Full article

Ultrasonic thickness resonance can be effectively used to detect and quantify the level of corrosion in steel nuclear storage containers as well as other corrosion-prone thin-walled structures, such as pipes and storage tanks. Electro-Magnetic Acoustic Transducers (EMATs) have several advantages over more traditional piezoelectric-based transducers; namely, they can be used in a non-contact fashion on robotic platforms, allowing for measurements regardless of surface conditions or temperature. The major challenge of EMAT application is the power required to counteract the low actuation efficiency, which is achieved with a high-power ultrasonic pulse generator and a transformer circuit. Resonance techniques, in which most of the energy is concentrated near structural resonance frequencies, are preferable to improve efficiency of electro-magnetic acoustic measurements. This methodology was applied to 316L stainless steel thin plates subjected to uniform corrosion as well as pitting corrosion imitating different damage scenarios in a nuclear waste container. The resonant peak frequency shift was found to be proportional to the severity of corrosion for minimally corroded samples. However, the complete disappearance of the resonance peak was observed in the samples with severe corrosion damage. The EMAT liftoff distance was studied to quantify its effect on the amplitude, spread, and frequency of resonant peaks. Recommendations for use of EMATs for assessing corrosion damage are presented. The study demonstrates the success of frequency-based detection of corrosion damage in 316L stainless steel used in fabrication of nuclear waste storage containers. Full article

This study investigates an IPS-type Metglas/PMN-PT laminated magnetoelectric composite and its feasibility as a reciprocal mechanical magnetoelectric antenna for low-frequency transmission and reception. Finite-element simulations under quasi-static and frequency-domain conditions reveal strong magnetoelectric coupling under an optimal DC bias field, with both the direct magnetoelectric effect (DME) and converse magnetoelectric effect (CME) exhibiting pronounced resonance near 14.5 kHz, governed by the same longitudinal extensional vibration mode. Five IPS samples were fabricated and experimentally characterized. All devices showed resonant frequencies within 14.1–14.5 kHz, peak DME coefficients of 3.0 × 10⁶ to 3.9 × 10⁶ pC/Oe, and peak CME coefficients of 12.0~15.8 Oe·cm/V, confirming good fabrication consistency, transmit–receive reciprocity, and array-integration potential. The parallel IPS antenna generated a magnetic flux density of 37 nT at 1 m, and exhibited an equivalent magnetic noise of 63 fT/Hz^1/2 at 14.45 kHz. These results demonstrate that the proposed IPS structure combines high-sensitivity reception with efficient low-frequency transmission, showing strong potential for miniaturized, low-power, and long-range magnetic communication and underwater communication applications. Full article

Reservoir effectiveness in marine shales is controlled not only by pore volume but also by pore-fluid occurrence, pore–throat connectivity, and mineral–organic matter coupling. In this study, the Permian Gufeng Formation shales from the Enshi area, western Hubei, South China, were investigated through an integrated analysis of total organic carbon (TOC), X-ray diffraction (XRD)-based mineral composition and lithofacies, low-field nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), micro-computed tomography (Micro-CT), and entropy-weighted technique for order preference by similarity to an ideal solution (TOPSIS) evaluation. The TOC content ranges from 1.60% to 21.38% and shows clear vertical differentiation, with moderate but variable enrichment in the lower interval, reduced organic matter abundance in the middle interval, and pronounced organic enrichment in the upper interval. Mineral compositions demonstrate an upward transition from a mixed siliceous–carbonate system to a dominantly siliceous shale system. NMR results reveal strong heterogeneity in porosity, NMR-derived permeability, T2cutoff, bound-fluid saturation, and free-fluid saturation. Based on saturated and centrifuged T2 spectra, four descriptive reservoir response types were identified: short-T2-dominated micropore-bound response, intermediate-T2-dominated movable-fluid response, long-T2-enriched but low-efficiency response, and NMR-inferred enhanced mobility composite response. SEM observations show diverse pore types, including organic-matter-related pores, dissolution pores, interparticle pores, mineral-edge pores, pyrite intercrystalline pores, and local microfracture-like pores. Micro-CT results indicate that micrometer-scale pore bodies are commonly isolated, demonstrating that pore abundance or pore size alone cannot determine reservoir effectiveness. TOC mainly controls pore generation potential, whereas siliceous minerals, pore–throat connectivity, movable fluid proportion, and local fractures exert stronger controls on effective reservoir development. The most favorable reservoir responses are concentrated in the upper high-organic siliceous shale interval from A33 to A42, with local enhanced responses in A16 and A21. These results provide an integrated framework for evaluating reservoir heterogeneity and favorable intervals in complex marine shale systems. Full article

Magnetic flux leakage (MFL) testing is a vital non-destructive testing method used to identify defects in oil and gas pipelines and critical components. However, variations in defect geometry and testing conditions can lead to inaccurate data and imbalanced feature distributions, which compromise detection outcomes. To address these challenges, this paper presents a defect classification approach for MFL testing based on generating expansion and the Dual-Channel Vision Transformer (DC-ViT). First, COMSOL finite element software (version 6.1) was used to simulate magnetic flux leakage for different types of pipeline defects. Axial and radial dual-channel signals were extracted to create the initial dataset. Next, a Conditional Variational Autoencoder (CVAE) was used for Generate Expansion to effectively mitigate sample scarcity and defect category imbalance. Finally, the DC-ViT model was constructed and trained using the Generate Expansion dataset as input to achieve multidimensional feature fusion and classification prediction for defects. Experimental results demonstrate 97.97% detection accuracy. The DC-ViT model outperforms traditional convolutional neural networks and single-channel models in terms of accuracy, precision, recall, and F1-score. These results validate the method’s effectiveness and robustness in complex defect scenarios and offer a novel approach to magnetic leakage signal detection. Full article

This study investigated the effect of MoS₂/graphite lubricant composition on the high-temperature compaction behavior, local mechanical uniformity, and microstructural characteristics of Fe–5.0 wt.%Si SMCs. Nine lubricant compositions were prepared by varying MoS₂ and graphite contents, and their friction behavior, Vickers hardness, and compaction behavior were evaluated experimentally and by FEA. One-way ANOVA confirmed that lubricant composition significantly affected the Vickers hardness response (F = 4.245, p = 0.000273). The measured friction coefficients were applied as interface friction conditions in FEA, and the relative density, effective strain, and absolute hydrostatic stress distributions were compared. Among the investigated compositions, C3, containing 1.0 wt.% MoS₂ and 0.3 wt.% graphite, showed the lowest friction coefficient and Vickers hardness standard deviation. In FEA, C3 also showed balanced relative density, effective strain, and hydrostatic stress distributions. XRD confirmed the α-Fe-based bcc Fe–Si matrix, while SEM-EDS indicated locally distributed lubricant-derived residual regions. Therefore, C3 was selected as the most balanced lubricant composition within the investigated range. Future studies will evaluate electromagnetic properties, including core loss and magnetic permeability. Full article

We demonstrate an efficient machine learning (ML) model for the prediction of magnetic property changes in ${\mathrm{Nd}}_2$${\mathrm{Fe}}_{14}$B-based permanent magnets given a large range of different impurity elements. We show that relatively simple models can be sufficient to capture complex changes in the saturation magnetization ${\mathrm{M}}_s$ and the magnetocrystalline anisotropy constant ${\mathrm{K}}_1$. As the necessity for recycling the raw material of permanent magnets increases, the variety of impure chemicals and their concentrations increase as well. Some chemical elements with antiferromagnetic or complex magnetic ground states like Cr, Mn and Sm pose difficulties in the training of an ML model that can be effectively mitigated by feature engineering. This enables us to create a single model capable of describing more than twenty substitutional elements in a wide range of concentrations. Full article

The magnetic properties of Dy₆MnBi₂ and Dy₆FeBi₂ intermetallic compounds have been investigated within the framework of density functional theory. These materials are attracting considerable attention due to their potential in magnetic refrigeration applications, as they exhibit a pronounced magnetocaloric effect. In the present work, we compute the equation of state, electronic density of states, and magnetic moments, and compare the results with available experimental data. The calculated quantities are found to be in good agreement with the experimental findings, thereby supporting once again the reliability of DFT as a theoretical framework for exploring the magnetic behavior of ternary intermetallic compounds. Full article

Wireless power transfer (WPT) systems for electric vehicles (EVs) are increasingly being studied in the MHz range to increase power density and reduce the size of passive components. However, operation at higher frequencies significantly changes electromagnetic interference (EMI) behaavior. Fast switching in SiC- and GaN-based inverters, high-Q resonant operation, and frequency-dependent parasitic capacitances create conductive, capacitive, and magnetic interference mechanisms that are less significant in conventional kHz-range systems. Although many existing studies focus on power-transfer efficiency and converter optimization, EMI mechanisms in MHz-range EV WPT systems remain insufficiently systematized from a system-level electromagnetic perspective. This paper presents a state-of-the-art review of EMI generation mechanisms and system-level effects in high-frequency WPT systems for electric vehicles. The review considers the main interference sources and coupling paths, including switching-induced common-mode currents, resonant amplification of current and voltage stress, capacitive coupling between the coupler and nearby conductive structures, and magnetic-field redistribution caused by coil misalignment. Special attention is given to the transition from lumped-element assumptions to more distributed electromagnetic behavior at higher frequencies. The review also discusses the possible impact of these mechanisms on vehicle electronic subsystems and highlights the need for frequency-aware electromagnetic design, integrated modeling, and more rigorous EMC assessment for reliable MHz-range wireless EV charging systems. Full article

Axial–radial flux permanent magnet synchronous machines (ARFPMSMs) are an emerging family of electrical machines that combine radial flux and axial flux topologies within a single electromagnetic structure. By using multiple radial and axial air gaps, they increase the effective torque-producing surface without enlarging the machine envelope, which enables higher torque density and better utilization of active materials than in conventional single-flux topologies. This makes them attractive for traction, aerospace, wind, elevator and other compact high-torque applications. This paper reviews the state of the art of ARFPMSMs and provides four main contributions. First, it proposes a unified topology-oriented classification of classical PM-only, hybrid-excitation and vernier/flux-modulated ARFPMSMs, while clarifying their conceptual boundary with transverse-flux machines. Second, it consolidates published designs and compares key parameters across the three families. Third, it summarizes experimentally validated prototypes, including rated power, torque density, materials and cooling methods. Finally, it identifies open research challenges and outlines future directions, including surrogate models, Bayesian optimization and active cooling strategies. Full article

Background: Myocardial scar segmentation from late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) images plays an important role in cardiac disease assessment and prognosis evaluation. However, accurate scar annotation is labor-intensive and requires substantial clinical expertise because scar regions are typically small, irregularly shaped, and characterized by ambiguous boundaries. Although scribble supervision provides a more practical alternative to dense annotation by substantially reducing labeling costs, the extreme sparsity of scribbles and the high similarity between scar tissue and surrounding myocardium make accurate weakly supervised segmentation challenging. Methods: To address these challenges, we propose SSMSNet, a novel scribble-supervised framework for myocardial scar segmentation. Specifically, a weakly supervised anatomical segmentation network is first employed to provide reliable myocardial structural priors and suppress irrelevant background interference. Subsequently, a local distance prior map is dynamically generated from scribble annotations, and a corresponding loss is introduced to enhance structural awareness and improve training stability. Meanwhile, by leveraging the spatial correlation between the myocardium and scar regions, teacher–student consistency supervision progressively recovers more complete scar structures from sparse annotations. Furthermore, a detail-aware feature enhancement module strengthens low-level representations through contextual interactions and attention mechanisms, improving the perception of scars with ambiguous boundaries. Results: Extensive experiments conducted on two public cardiac pathology datasets demonstrate that the proposed framework consistently outperforms state-of-the-art scribble-supervised methods and achieves competitive performance compared with fully supervised methods. Conclusions: The proposed SSMSNet effectively alleviates the limitations imposed by scribble annotations by integrating anatomical guidance, local distance priors, and consistency learning. These findings suggest that the framework provides an effective and annotation-efficient solution for myocardial scar segmentation in LGE CMR images. Full article