Search Results (288)

This work explores the mechanical responses of 3D-printed periodic arch-inspired structures (PASs) and PASs doped with NdFeB powder to advance their application in lightweight structural load-bearing and future structure–function integration. Three PAS configurations were fabricated via digital light processing (DLP), and magnetic PASs (MPASs) were produced by dispersing NdFeB powder (1–3 g/200 mL) into photosensitive resin. Under quasi-static compression, key mechanical properties—Young’s modulus (E), yield strength (σ_y), and compressive strength (σ_c)—of non-magnetic PASs increase linearly with relative density (ρ* = 0.18–0.48): for PAS22, E rises from 68.1 to 200.3 MPa (+194%), σ_y from 2.18 to 6.75 MPa (+210%), and σ_c from 2.98 to 9.07 MPa (+204%). Under dynamic impact (~100 s⁻¹), mechanical enhancement is even more pronounced: E of PAS22 surges to 814.8 MPa (3.2× higher than quasi-static), and σ_c reaches 11.54 MPa. Finite element simulations reveal that the Ideal Plastic Model best predicts quasi-static brittle fracture, whereas the Hardening Function Model captures dynamic behavior most accurately. Stress and plastic strain concentrate at the straight–arc junctions—identified as critical weak points. MPASs exhibit higher stiffness and yield strength (e.g., E of MPAS22 up to 896.5 MPa under impact) but lower compressive strength (e.g., 11.01 MPa vs. 11.54 MPa for NMPAS22), attributed to NdFeB-induced brittleness that shifts the failure mode from “local damage accumulation” to “rapid overall failure”. This study establishes quantitative doping–structure–property correlations, providing design guidelines for next-generation functional arch-inspired metamaterials toward magnetically responsive, load-bearing applications. Full article

This paper provides a systematic review of the progress in encoded microsphere suspension array technology and its application in the multiplex detection of mycotoxins. Mycotoxins are diverse and frequently coexist in food matrices, leading to synergistic toxic effects. This poses significant challenges to existing risk assessment systems. Current multiplex detection methods still face technical bottlenecks such as target loss, matrix interference, and reliance on large-scale instruments. Suspension array technology based on encoded microspheres, combined with efficient signal amplification strategies, offers an ideal platform for achieving highly sensitive and high-throughput analysis of mycotoxins. This paper systematically reviews the core aspects of this technology, including encoding strategies such as physical, optical, and multi-dimensional approaches, along with new encoding materials like aggregation-induced emission materials and fluorescent proteins. It further covers matrix materials and preparation methods with an emphasis on green, biocompatible options and integrated fabrication techniques, as well as signal amplification mechanisms based on nucleic acid amplification, enzyme catalysis, and nanomaterials. The integration of magnetic separation techniques and the combination with portable, smartphone-based platforms for intelligent on-site detection are also highlighted. Finally, this review outlines future development trends such as the incorporation of artificial intelligence, 3D printing, and smart algorithms, aiming to provide theoretical references and technical support for research and applications in related fields. Full article

Magnetic filaments for fused deposition modeling, 3D printing, were produced by depositing polyamide 11 (PA11), by liquid–liquid phase separation and precipitation, onto exchange-coupled nanocomposite magnetic powders, SmCo₅ + 20 wt% Fe produced by mechanical milling and subsequent annealing. The produced filaments have good mechanical properties, a tensile strength of 32 MPa and a maximum elongation of slightly over 40%. The filaments also present good magnetic properties: a high coercive field of 1 T at 300 K and nearly double the saturation magnetization and remanence, compared to filaments made by depositing PA11 on commercial SmCo₅ and recycled SmCo₅ powders and four times the energy product. This work shows that magnetic filaments made by encapsulating exchange-coupled magnetic nanocomposite powders in PA11 may be a viable option for the production of 3D-printed isotropic bonded magnets, as the high energy product and remanence especially can lead to a reduction in both magnetic powder quantity and rare earth elements required for high performance magnetic filaments. This in turn may reduce costs and improve sustainability. Full article

Bioprinting of Advanced Therapy Medicinal Products offers promising new strategies for personalized medicine, but it requires comprehensive, non-destructive characterization and quality monitoring. To support patients with tailor-made constructs composed of hydrogels and cells derived from allogeneic donors or autologous samples, several challenges must be addressed—such as on-demand production, robust manufacturing, appropriate storage and logistics, and destruction-free quality control—before successful translation into clinical applications or pharmacy is possible. Although experience in cryo-preservation, blood banking, and organ donation helps to identify critical process parameters, detecting variations in manufacturing and ensuring product stability remain essential. Quality monitoring of 3D-printed objects before and after storage by magnetic resonance imaging (MRI) is complemented here by measurements of total mass and volume. These established methods provide rapid, non-destructive feedback and have well-characterized statistical limitations. Total mass can be assessed quickly; however, such integral measurements do not reveal information about internal structures. MRI, in contrast, offers detailed, spatially resolved insights. By combining these analytical modalities, we quantitatively analyzed the storage stability of 3D-printed hydrogels—without living cells in this study—in order to demonstrate and validate the analytical approach. We describe a workflow for measuring mass and geometry of 3D-printed hydrogel lattices before and after storage under varying process parameters. Critical quality attributes (cQAs), including overall and internal structural fidelity as well as mass conservation, were monitored. The presented workflow supports the development of cryopreservation protocols and has potential applications in biomaterial development for bioprinting and in quality assessment of tailor-made artificial tissues. Full article

Superparamagnetic iron oxide nanoparticles (SPIONs) have shown promise across a wide range of biomedical applications, including targeted drug delivery, magnetic hyperthermia, magnetic resonance imaging, and regenerative medicine. In the context of local tumor therapy (Magnetic Drug Targeting, MDT) SPIONs can be functionalized with chemotherapeutic agents and accumulated at tumor sites using an externally applied magnetic field. To achieve effective drug accumulation and therapeutic efficacy, precise positioning of the accumulation magnet relative to the tumor is essential. To address this need, we propose a dual-modality ultrasound imaging approach combining magnetomotive ultrasound (MMUS) and passive cavitation mapping (PCM). MMUS detects magnetically induced displacements to localize SPIONs embedded in elastic tissue, while PCM monitors cavitation emissions from circulating SPIONs under focused ultrasound exposure. In addition to detection, PCM has the potential to enable feedback-based control of cavitation exposure, allowing cavitation parameters to be kept within a safe regime. The dual imaging modality approach was validated using standard phantoms and a complex carotid bifurcation tumor flow phantom fabricated via 3D printing. Experimental results demonstrate the first coordinated spatiotemporal imaging of MMUS and PCM within the same anatomical model, resolving the key bottleneck of SPIONs monitoring in blood vessels/tissue. This demonstrates the strong potential of complementary MMUS and PCM imaging for monitoring in preclinical and clinical MDT settings. Full article

In the last decade, interactive tabletops have emerged as a hardware solution for collaborative interactions, providing shared workspaces that support group learning and work. However, despite a variety of studies highlighting their benefits, adoption in educational and professional environments remains limited due to high cost, weight, and spatial constraints. This paper presents an alternative hybrid approach of augmenting static surfaces (e.g., printed images or plans) with off-the-shelf mobile devices through a dynamic peephole interaction. The system uses a rotating, asymmetric static magnet and magnetometers commonly found in all mobile devices, requiring solely software on the device to calculate its relative position based on field strength and relative angle. This first prototype is affordable (∼€10), easy to build with a minimal set of components (e.g., LEGO or 3D-printed parts), device-independent, and offers an accuracy of 1.4 cm, with potential for improvements both to accuracy and the currently limited operating range of 30 cm. Full article

Optically detected magnetic resonance (ODMR) of nitrogen-vacancy centers in diamonds, in addition to optical excitation with green light, requires microwave excitation and thus a microwave structure. While many different microwave structures including microwave resonators have been presented in the past, none of them fulfilled the need to fit inside the miniaturized quantum magnetometer with limited space used in this work. This is why a novel microwave resonator design using commercially available printed circuit board technology is proposed. It is demonstrated that this design is of small form factor, highly power efficient and low-cost, with very good reproducibility, and in addition, it can be fabricated as a flexible printed circuit board to be bent and thus fit into the miniaturized sensor used in this work. The design choices made for the resonator and the way in which it was trimmed and optimized geometrically are presented and ODMR spectra made with a miniaturized quantum sensor in combination with such a resonator, which was fed by a microwave generator set to different microwave powers, are shown. These measurements revealed that a microwave power of −4 dBm is sufficient to excite the m_s = ±1 states of the nitrogen-vacancy centers, while exceeding −1 dBm already introduces sidebands in the ODMR spectrum. This underlines the efficiency of the resonator in exciting the nitrogen-vacancies of the diamond in the sensor platform used and can lead to development of low-power quantum sensors in the future. Full article

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique extensively utilized in neuroscience and clinical medicine; however, its underlying mechanisms require further elucidation. Due to ethical safety considerations, low cost, and physiological similarities to humans, rodent models have become the primary subjects for TMS animal studies. Nevertheless, existing TMS coils designed for rodents face several limitations, including size constraints that complicate coil fabrication, insufficient stimulation intensity, suboptimal focality, and difficulty in adapting coils to practical experimental scenarios. Currently, many studies have attempted to address these issues through various methods, such as adding magnetic nanoparticles, constraining current distribution, and incorporating electric field shielding devices. Integrating the above methods, this study designs a small arc-shaped TMS coil for the frontoparietal region of rats using the inverse boundary element method, which reduces the coil’s interference with experimental observations. Compared with traditional geometrically scaled-down human coil circular and figure-of-eight coils, this coil achieves a 79.78% and 57.14% reduction in half-value volume, respectively, thus significantly improving the focusing of stimulation. Meanwhile, by adding current density constraints while minimizing the impact on the stimulation effect, the minimum wire spacing was increased from 0.39 mm to 1.02 mm, ensuring the feasibility of the coil winding. Finally, coil winding was completed using 0.05 mm × 120 Litz wire with a 3D-printed housing, which proves the practicality of the proposed design method. Full article

Reed sensors play an important role in improving the safety, reliability, and efficiency of modern electric vehicles. Our study evaluates their performance by measuring the switching distance under five different configurations of a cylindrical magnet using a 3D-printed test fixture. Statistical analysis revealed that the right-shift-upward configuration yielded the best performance, significantly reducing the release distance. Building on this, a prototype housing was developed using Selective Laser Sintering with polybutylene terephthalate, and a stainless-steel spring was incorporated to enhance sensitivity and reliability. The spring integration reduced the activation distance to 2.3 mm, which is an improvement of up to 60%, and it also significantly improved the consistency of the results. These outcomes demonstrate a practical method for manufacturing more reliable reed sensors for automotive sensing technology. Full article

Additive manufacturing technologies are characterised by the capability to produce components with complex geometries that are difficult to achieve using conventional methods. Despite the wide range of available materials and additive manufacturing processes, fulfilling design requirements related to surface structure parameters remains a considerable challenge. This paper presents the findings of an investigation into the influence of abrasive treatment of a ferromagnetic fluid on the surface roughness of MEX-printed samples. The samples were fabricated using TPU 95A material. The abrasive medium employed in the study comprised carbonyl iron and silicon carbide. A dedicated tool was designed for the experiments, incorporating neodymium magnets arranged in four asymmetrically distributed slots. The proposed tool represents an unconventional approach in comparison with existing practices. Tests were conducted in three measurement series—B, C, and D—while series A served as the control group. Analysis of the experimental results revealed that, for the parameters Sp (height of the highest apex) and Sz (maximum height, defined as the sum of Sp and Sv, representing the height of the highest apex and the maximum pit depth, respectively), the most significant reduction in parameter values was observed for series D. Full article

Digital light processing (DLP) 3D printing is a powerful additive manufacturing technique but is limited by the relatively low mechanical strength of cured neat resin parts. In this study, a renewable bio-adhesive lignin was introduced as a reinforcing filler into a bisphenol A-type epoxy acrylate (EA) photocurable resin to enhance the mechanical performance of DLP-printed components. Lignin was incorporated at low concentrations (0–0.5 wt%), and three dispersion methods—magnetic stirring, planetary mixing, and ultrasonication—were compared to optimize the filler distribution. Cure depth tests and optical microscopy confirmed that ultrasonication (40 kHz, 5 h) achieved the most homogeneous dispersion, yielding a cure depth nearly matching that of the neat resin. DLP printing of tensile specimens demonstrated that as little as 0.025 wt% lignin increased tensile strength by ~39% (from 44.9 MPa to 62.2 MPa) compared to the neat resin, while maintaining similar elongation at break. Surface hardness also improved by over 40% at this optimal lignin content. However, higher lignin loadings (≥0.05 wt%) led to particle agglomeration, resulting in diminished mechanical gains and impaired printability (e.g., distortion and incomplete curing at 1 wt%). Fractographic analysis of broken specimens revealed that well-dispersed lignin particles act to deflect and hinder crack propagation, thereby enhancing fracture resistance. Overall, this work demonstrates a simple and sustainable approach to reinforce DLP 3D-printed polymers using biopolymer lignin, achieving significant improvements in mechanical properties while highlighting the value of bio-derived additives for advanced photopolymer 3D printing applications. Full article

Yield stress and thixotropy are critical rheological properties for enabling successful 3D printing of magnetic colloidal systems. However, conventional magnetic colloids, typically composed of a single dispersed phase, exhibit insufficient rheological tunability for reliable 3D printing. In this study, we developed a novel magnetic colloidal system comprising a carrier liquid, magnetic nanoparticles, and organic modified bentonite. A direct-ink-writing 3D-printing platform was specifically designed and optimized for thixotropic materials, incorporating three distinct extruder head configurations. Through an in-depth rheological investigation and printing trials, quantitative analysis revealed that the printability of magnetic colloids is significantly affected by multiple factors, including magnetic field strength, pre-shear conditions, and printing speed. Furthermore, we successfully fabricated 3D architectures through the precise coordination of deposition paths and magnetic field modulation. This work offers initial support for the material’s future applications in soft robotics, in vivo therapeutic systems, and targeted drug delivery platforms. Full article

This paper presents the design and experimental validation of a 3D-printed BLDC motor featuring a hollow-shaft rotor and nickel-reinforced stator. The rotor employs neodymium magnets to reduce inertia while maintaining torque density, and the stator integrates thin nickel laminations to improve flux density. A custom controller with Hall sensors, BiSS-C encoder, and CAN interface enables closed-loop position control. Experiments demonstrate stable tracking with short settling time and negligible steady-state error, confirming feasibility for robotic and precision applications. Full article

Considering that soft airbag sensors made from soft materials are limited to detecting only normal forces, a novel PEBA–silicone composite magneto-sensitive airbag sensor is proposed for simultaneously detecting normal contact force and horizontal motion during human–robot interaction. In terms of structural design, the PEBA–silicone composite airbag is manufactured using fused deposition modeling, 3D printing, and silicone casting, achieving a balance between high airtightness and adjustable stiffness. Beneath the airbag, a magneto-sensitive substrate with several NdFeB magnets is embedded, while a fixed Hall sensor detects spatially varying magnetic fields to determine horizontal displacements without contact. The results of contact-force and motion experiments show that the proposed sensor achieves a force resolution of 20 g, a force range of 0 to 1100 g, a fitting sensitivity of 7.54 N/Pa, an average static stiffness of 4.82 N/mm, and a horizontal motion detection range of 0.125 to 1 cm/s. In addition, the prototype of the sensor is lightweight (with the complete assembly weighing 81.25 g and the sensing part weighing 56.13 g) and low-cost, giving it potential application value in exoskeletons and industrial grippers. Full article

In this study, we examined how printing temperature affects the microstructure and mechanical properties of polylactic acid (PLA) composite reinforced with iron oxide i.e., magnetite manufactured using a material extrusion technique. The composite was printed at temperatures from 185 °C to 215 °C. Microstructure analysis via synchrotron radiation X-ray microtomography revealed changes in both iron oxide and porosity contents within the printed structures. Mechanical testing results demonstrated a limited effect of the printing temperature on tensile performance. Finite element computation is considered to predict the elasticity behavior of the printed composite by converting 3D images into 3D structural meshes. When implementing a two-phase model, the predictions show a leading role of the iron oxide content, and an overestimation of the stiffness of the composite. A three-phase model demonstrates a better matching of the experimental results suggesting a limited load transfer across the PLA-iron oxide interface with Young’s moduli in the interphase zone as small as 10% of PLA Young’s modulus. Magnetic actuation demonstrates that experiments on PLA-iron oxide plates reveal a pronounced thickness-dependent limitation, with the maximum deflection observed in thin strips of 0.4 mm. Full article