Search Results (15)

Local temperature measurement is crucial for understanding nanoscale thermal transport and developing nanodevices for biomedical, photonic, and optoelectronic applications. The rise of photothermal therapy for cancer treatment has increased the demand for high-resolution nanothermometric techniques capable of non-contact intracellular temperature measurement and modification. Raman spectroscopy meets this need: the ratio of anti-Stokes to Stokes Raman intensities for a specific vibrational mode correlates with local temperature through the Boltzmann distribution. The present study proposes a novel photothermal therapy agent designed to advance the current state of the art while adhering to green chemistry principles, thereby favoring low-temperature synthesis involving limited energy consumption. A key challenge in this field is to achieve close contact between plasmonic nanosystems, which act as nanoheaters, and local temperature sensors. This is achieved by employing silver nanoparticles as a heat release agent, coated with anatase-phase titanium dioxide, as a local temperature sensor. The proposed synthesis, which combines refluxing and subcritical solvothermal treatments, enables direct anatase formation, despite its metastability under standard conditions, thus eliminating the need for a calcination step. Structural characterization through SAED-HRTEM and Raman spectroscopy confirms the successful crystallization of the desired phase. Moreover, the nanothermometry measurements conducted at various wavelengths ultimately demonstrate both the effectiveness of these nanomaterials as thermometric probes, with a relative sensitivity of about 0.24 K⁻¹%, and their capability as local heaters, with a release of a few tens of degrees. This work demonstrates a new synthetic strategy for these nanocomposites, which offers a promising pathway for the optimization of nanosystems in therapeutic applications. Full article

Flexible wearable electronics face critical challenges in achieving reliable physiological monitoring, particularly due to the trade-off between sensitivity and durability in flexible electrodes, compounded by mechanical modulus mismatch with biological tissues. To address these limitations, we develop an anti-freezing ionic hydrogel through a chitosan/acrylamide/LiCl system engineered via the solution post-treatment strategy. The optimized hydrogel exhibits exceptional ionic conductivity (24.1 mS/cm at 25 °C) and excellent cryogenic tolerance. Leveraging these attributes, we construct a gel-based triboelectric nanogenerator (G-TENG) that demonstrates ultrahigh sensitivity (1.56 V/kPa) under low pressure. The device enables the precise capture of subtle vibrations at a frequency of 1088 Hz with a signal-to-noise ratio of 16.27 dB and demonstrates operational stability (>16,000 cycles), successfully differentiating complex physiological activities including swallowing, coughing, and phonation. Through machine learning-assisted analysis, the system achieves 96.56% recognition accuracy for five words and demonstrates good signal recognition ability in different ambient sound scenarios. This work provides a paradigm for designing environmentally adaptive wearable sensors through interfacial modulus engineering and ion transport optimization. Full article

Raman spectroscopy is a type of inelastic scattering that provides rich information about a substance based on the coupling of the energy levels of their vibrational and rotational modes with an incident light. It has been applied extensively in many fields. As there is an increasing need for the remote detection of chemicals in planetary exploration and anti-terrorism, it is urgent to develop a compact, easily transportable, and fully automated remote Raman detection system for trace detection and identification of information, with high-level confidence about the target’s composition and conformation in real-time and for real field scenarios. Here, we present an unmanned vehicle-based remote Raman system, which includes a 266 nm air-cooling passive Q-switched nanosecond pulsed laser of high-repetition frequency, a gated ICMOS, and an unmanned vehicle. This system provides good spectral signals from remote distances ranging from 3 m to 10 m for simulating realistic scenarios, such as aluminum plate, woodblock, paperboard, black cloth, and leaves, and even for detected amounts as low as 0.1 mg. Furthermore, a convolutional neural network (CNN)-based algorithm is implemented and packaged into the recognition software to achieve faster and more accurate detection and identification. This prototype offers a proof-of-concept for an unmanned vehicle with accurate remote substance detection in real-time, which can be helpful for remote detection and identification of hazardous gas, explosives, their precursors, and so forth. Full article

This study presents the synthesis of glucosamine-modified mesoporous silica-coated magnetic nanoparticles (MNPs) as a therapeutic platform for the delivery of an anticancer drug, methotrexate (MTX). The MNPs were coated with mesoporous silica in a templated sol–gel process to form MNP@MSN, and then chloropropyl groups were added to the structure in a post-modification reaction. Glucosamine was then reacted with the chloro-modified structure, and methotrexate was conjugated to the hydroxyl group of the glucose. The prepared structure was characterized using techniques such as Fourier transform infrared (FT-IR) spectroscopy, elemental analysis (CHN), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), a vibrating sample magnetometer (VSM), and X-ray diffraction (XRD). Good formation of nano-sized MNPs and MNP@MSN was observed via particle size monitoring. The modified glucosamine structure showed a controlled release profile of methotrexate in simulated tumor fluid. In vitro evaluation using the 4T1 breast cancer cell line showed the cytotoxicity, apoptosis, and cell cycle effects of methotrexate. The MTT assay showed comparable toxicity between MTX-loaded nanoparticles and free MTX. The structure could act as a glucose transporter-targeting agent and showed increased uptake in cancer cells. An in vivo breast cancer model was established in BALB/C mice, and the distribution of MTX-conjugated MNP@MSN particles was visualized using MRI. The MTX-conjugated particles showed significant anti-tumor potential together with MRI contrast enhancement. Full article

In the process of landscaping or afforestation in challenging terrain, in order to improve the survival rate of transplanted seedlings, it is necessary to transplant seedlings with a mother soil ball attached. During transportation, the soil ball at the root of the seedlings is very susceptible to breakage due to compression, bumps, and collisions. In order to ensure the integrity of the soil ball of the transplanted seedlings and improve the survival rate of seedlings, a method of chemically enhancing the soil surface strength was employed. Specifically, a polymer-based soil consolidating agent was used to solidify the root balls of the seedlings. To examine the abrasion resistance performance of the soil balls formed by consolidating the surface with polymer adhesive during the transportation process, we utilized a polymer-based consolidating agent to prepare test soil columns and developed a method to simulate the damage resistance performance of seedling root balls during transportation using these soil columns. The method primarily encompasses two aspects of testing: compressive strength testing of the consolidated soil columns and resistance to transportation vibration testing. The first method for testing the resistance to transportation vibration of the consolidated soil columns is a combination test that includes three sets of tests: highway truck transportation vibration testing, combined wheel vehicle transportation vibration testing, and impact testing. Although the method is cumbersome, testing is more accurate. The second method for testing the resistance to transportation vibration of the consolidated soil columns involves simultaneously testing multiple consolidated soil columns using a simulated transportation vibration test platform. The testing method is concise and efficient, and the test results are more intuitive. The combined assessment of the resistance to transportation vibration and compressive strength testing of the consolidated soil columns allows for a comprehensive evaluation of the soil columns’ resistance to damage during transportation. This study mainly provides a quick and effective method for detecting the damage resistance of consolidated soil columns/balls during transportation, providing technical support for the application of polymer-based consolidation agents in the field of seedling transplantation. Full article

Underground coal mines belong to the GNSS-denied environment, and the Strapdown Inertial Navigation System (SINS) has a significant advantage in the precise positioning of equipment in this environment because of its operation without requiring interaction with external information and strong anti-interference capabilities. Nonetheless, the vibrations of the installation platform adversely affect the positioning accuracy of SINS. This article focuses on the monorail crane in coal mines as the subject of research, developing a dynamic model for the motion unit consisting of the “track + drive unit + driver’s cab”, while analyzing the relationship between track roughness conditions and the vibration excitation of this unit. Subsequently, utilizing the dynamic model, the study calculated the angular and linear vibration characteristics and formulated models to address coning error and sculling error specific to the SINS in this vibration condition. Lastly, by employing a multi-sample compensation algorithm, this article compensated for positioning errors in the SINS caused by track roughness-induced vibrations during uniform straight-line motion of the motion unit, thus achieving optimal positioning information for the monorail crane. The simulation results demonstrated that employing a four-sample compensation algorithm reduces the coning error in SINS positioning calculations by a minimum of 50% and decreases the sculling error by at least 31%, satisfying the positioning accuracy requirements for precise parking of the monorail crane during the transportation phase, while establishing the foundation for autonomous precise positioning and integrated navigation of underground track transport equipment in coal mines. Full article

Spin-pumping-induced damping and interfacial Dzyaloshinskii–Moriya interaction (iDMI) have been studied in Pt/Co₂FeAl/MgO systems grown on Si or MgO substrates as a function of Pt and Co₂FeAl (CFA) thicknesses. For this, we combined vibrating sample magnetometry (VSM), microstrip ferromagnetic resonance (MS-FMR), and Brillouin light scattering (BLS). VSM measurements of the magnetic moment at saturation per unit area revealed the absence of a magnetic dead layer in both systems, with a higher magnetization at saturation obtained for CFA grown on MgO. The key parameters governing the spin-dependent transport through the Pt/CFA interface, including the spin mixing conductance and the spin diffusion length, have been determined from the CFA and the Pt thickness dependence of the damping. BLS has been used to measure the spin wave non-reciprocity via the frequency mismatch between the Stokes and anti-Stokes lines. iDMI has been separated from the contribution of the interface perpendicular anisotropy difference between Pt/CFA and CFA/MgO. Our investigation revealed that both iDMI strength and spin pumping efficiency are higher for CFA-based systems grown on MgO due to its epitaxial growth confirmed by MS-FMR measurements of the in-plane magnetic anisotropy. This suggests that CFA grown on MgO could be a promising material candidate as a spin injection source via spin pumping and for other spintronic applications. Full article

A friction-driven forestry electric monorail car based on a wheel hub motor is designed with the aim of solving the problems of the low transportation capacity, low running speed, large turning radius, and poor stability of low-slope mountain forestry monorails. The relationships between the minimum turning radius and the steering spring elasticity coefficient, between the body tilt and the anti-tip spring elasticity coefficient, and between the minimum turning radius of the monorail car and the distance between the two chassis and the two steering wheels was provided by the theoretical calculation and analysis of the key parameters of a dual-chassis structure, steering device, and anti-tip device. The dimensional parameters of the key components were determined. The three-dimensional design of the overall car was carried out, and the feasibility of the design was verified in kinematic simulation experiments. A performance test of the monorail car was conducted with the minimum turning radius, maximum load capacity, maximum full load speed, climbing degree, and center of gravity offset as indicators. The test results show that the monorail car has a minimum turning radius of 3.3 m, a maximum load capacity of 300 kg, a maximum speed of 20 km·h⁻¹ fully loaded, a maximum gradient of 21°, and a unilateral vibration amplitude of 8 mm or less. The double-chassis structure and anti-tip device met the design requirements. The good transportation performance of the designed monorail car effectively solves the problems of a large turning radius and unstable driving of current forestry monorails. Additionally, the designed monorail car is environmentally friendly and efficient, meeting the requirements of monorail transporters for low-slope mountain forests and laying the foundation for the intelligent harvesting and transportation of mountain forest fruits. Full article

The energy-conversion stability of hydropower is critical to satisfy the growing demand for electricity. In low-head hydropower plants, a gravitational surface vortex is easily generated, which causes irregular shock vibrations that damage turbine performance and input-flow stability. The gravitational surface vortex is a complex fluid dynamic problem with high nonlinear features. Here, we thoroughly investigate its essential hydrodynamic properties, such as Ekman layer transport, heat/mass transfer, pressure pulsation, and vortex-induced vibration, and we note some significant scientific issues as well as future research directions and opportunities. Our findings show that the turbulent Ekman layer analytical solution and vortex multi-scale modeling technology, the working condition of the vortex across the scale heat/mass transfer mechanism, the high-precision measurement technology for high-speed turbulent vortexes, and the gas–liquid–solid three-phase vortex dynamics model are the main research directions. The vortex-induced vibration transition mechanism of particle flow in complex restricted pipelines, as well as the improvement of signal processing algorithms and a better design of anti-spin/vortex elimination devices, continue to draw attention. The relevant result can offer a helpful reference for fluid-induced vibration detection and provide a technical solution for hydropower energy conversion. Full article

(1) Background: with the development of intelligent transportation, effectively collecting and identifying the working state of vehicles is conducive to the analysis and processing of vehicle information by internet of vehicles, so as to reduce the occurrence of traffic accidents. Aiming at the problem of low identification accuracy of the mechanical vibration fault signal, a signal identification method based on time-frequency detection is introduced; (2) Methods: this paper constructs a parameter model of the synchroextracting S transform on the basis of the poor time-frequency concentration of the original S transform; (3) Results: in the case of SNR = −5~+30 dB, compared with other transformations, the Rényi entropy value of SEST is the smallest, and the Rényi entropy value is 0.5246 when SNR = +22 dB; (4) Conclusions: through simulation comparison and analysis, the excellent time-frequency concentration and anti-noise characteristics of the SEST are highlighted, and the rotor vibration fault signals such as rotor misalignment, unbalance and bearing wear are identified by SEST. Full article

Vibrations are a major cause of human health disorders, circuit boards and machinery damage. Vibration dampers are considered to be the best option to counter these issues. Three-dimensional printing techniques play an increasingly important role in manufacturing small polymer parts with tailored properties. Thermoplastic elastomers (TPE) constitute a perfect material for manufacturing small-scale series absorber prototypes due to their thermoplastic nature, good elasticity and damping properties. This paper proposes a novel multi-level approach to the design and manufacturing process, e.g., the first level—selection of material; second level—decision about the geometry of a damper; third—selection of technological printing parameters; fourth—post-printing treatment. This work primarily aims to overview the design and manufacturing process levels. The impact of each step on the damping capacity of small absorbers is assessed. It was found that thermoplastic elastomers and fused deposition modeling (FDM) have huge potential in shaping the physical properties of small, elastomeric absorbers. It was assessed that at every step of the multilevel design and manufacturing process (MDMP), the designer could tailor the damping to meet the desired criteria of a final product: a cylinder-shaped hollow damper that can be made from TPE polymer without post-printing treatment and is characterized by good damping. Full article

A common challenge faced by engineers in the hydraulic industry is the formation of free surface vortices at pump and power intakes. This undesirable phenomenon which sometimes entrains air could result in several operational problems: noise, vibration, cavitation, surging, structural damage to turbines and pumps, energy losses, efficiency losses, etc. This paper investigates the numerical simulation of an experimentally observed air-core vortex at an intake using the LTSInterFoam solver in OpenFOAM. The solver uses local time-stepping integration. In simulating the air-core vortex, the standard k − ε, realizable k − ε, renormalization group (RNG) k − ε and the shear stress transport (SST) k − ω models were used. The free surface was modelled using the volume of fluid (VOF) model. The simulation was validated using a set of analytical models and experimental data. The SST k − ω model provided the best results compared to the other turbulence models. The study was extended to simulate the effect of installing an anti-vortex device on the formation of a free surface vortex. The LTSInterFoam solver proved to be a reliable solver for the steady state simulation of a free surface vortex in OpenFOAM. Full article

The droplet response to vibrations has been well characterized on open substrates, but microfluidic applications for droplets on open systems are limited by rapid evaporation rates and prone to environmental contamination. However, the response of enclosed droplets to vibration is less understood. Here, we investigate the effects of a dual-plate enclosure on droplet transport for the anisotropic ratchet conveyor system. This system uses an asymmetric pattern of hydrophilic rungs to transport droplets with an applied vibration. Through this work, we discovered that the addition of a substrate on top of the droplet, held in place with a 3D printed fixture, extends the functional frequency range for droplet transport and normalizes the device performance for droplets of different volumes. Furthermore, we found that the edge movements are anti-phasic between top and bottom substrates, providing a velocity profile that is correlated to vibration frequency, unlike the resonance-dependent profiles observed on open systems. These results expand the capabilities of this system, providing avenues for new applications and innovation, but also new insights for droplet mechanics in response to applied vibration. Full article

Significant increase in the demand for freight and passenger transports by trains pushes the railway authorities and train companies to increase the speed, the axle load and the number of train carriages/wagons. All of these actions increase ground-borne noise and vibrations that negatively affect people who work, stay, or reside nearby the railway lines. In order to mitigate these phenomena, many techniques have been developed and studied but there is a serious lack of life-cycle information regarding such the methods in order to make a well-informed and sustainable decision. The aim of this study is to evaluate the life-cycle performance of mitigation methods that can enhance sustainability and efficacy in the railway industry. The emphasis of this study is placed on new methods for ground-borne noise and vibration mitigation including metamaterials, geosynthetics, and ground improvement. To benchmark all of these methods, identical baseline assumptions and the life-cycle analysis over 50 years have been adopted where relevant. This study also evaluates and highlights the impact of extreme climate conditions on the life-cycle cost of each method. It is found that the anti-resonator method is the most expensive methods compared with the others whilst the use of geogrids (for subgrade stiffening) is relatively reliable when used in combination with ground improvements. The adverse climate has also played a significant role in all of the methods. However, it was found that sustainable methods, which are less sensitive to extreme climate, are associated with the applications of geosynthetic materials such as geogrids, composites, etc. Full article

Continuous energy supply, a necessary condition for life, excites a state far from thermodynamic equilibrium, in particular coherent electric polar vibrations depending on water ordering in the cell. Disturbances in oxidative metabolism and coherence are a central issue in cancer development. Oxidative metabolism may be impaired by decreased pyruvate transfer to the mitochondrial matrix, either by parasitic consumption and/or mitochondrial dysfunction. This can in turn lead to disturbance in water molecules’ ordering, diminished power, and coherence of the electromagnetic field. In tumors with the Warburg (reverse Warburg) effect, mitochondrial dysfunction affects cancer cells (fibroblasts associated with cancer cells), and the electromagnetic field generated by microtubules in cancer cells has low power (high power due to transport of energy-rich metabolites from fibroblasts), disturbed coherence, and a shifted frequency spectrum according to changed power. Therapeutic strategies restoring mitochondrial function may trigger apoptosis in treated cells; yet, before this step is performed, induction (inhibition) of pyruvate dehydrogenase kinases (phosphatases) may restore the cancer state. In tumor tissues with the reverse Warburg effect, Caveolin-1 levels should be restored and the transport of energy-rich metabolites interrupted to cancer cells. In both cancer phenotypes, achieving permanently reversed mitochondrial dysfunction with metabolic-modulating drugs may be an effective, specific anti-cancer strategy. Full article