Field Sensor Research Articles

Dispersion and dissipation of shear horizontal wave in magneto-electro-elastic material loaded with complex magnetic viscous fluid

Abstract The present study outlines the theoretical analysis of Shear horizontal (SH) wave propagation on magneto-electro-elastic (MEE) material lying on an elastic half-space and subjected to magnetic fluid loading. Using an exact analytical approach, complex dispersion relations for SH waves are derived under both electric short and electric open boundary conditions. To validate these derived relations, specific cases are considered where the MEE material behaves as piezoelectric and piezomagnetic. The complex dispersion relations are separated into real and imaginary components, revealing nonlinear relationships between phase velocity and attenuation of SH waves in relation to geometric parameters, frequency, and the physical properties of the magnetic fluid. Five different magnetic fluids are examined to illustrate the phase velocity and attenuation characteristics graphically. The effects of geometric and physical parameters of the magnetic fluids, the thickness of the MEE material, and the frequency and density of the elastic half-space on the phase velocity and attenuation of SH waves are discussed. Additionally, the finite element method (FEM) is employed to validate the results, ensuring the accuracy of the analytical findings. The results of this study are fundamental and can be used to design and development of surface acoustic wave (SAW) liquid sensors as well as magnetic field sensors.

Dual-tapered fiber Mach–Zehnder interferometric magnetic field sensor based on magnetic fluid

Dual-tapered fiber Mach–Zehnder interferometric magnetic field sensor based on magnetic fluid

Magnetic field sensing with in-fiber cascaded Fabry-Perot interferometers (FPIs) using femtosecond laser direct writing

A magnetic field sensor made with femtosecond laser direct writing was built and characterized. The sensor makes use of the Vernier effect (VE) via a cascade of two Fabry-Perot interferometers (FPIs) with similar free spectra ranges (FSRs). The sensor cavity FPI 1 and the reference cavity FPI 2 are made by writing reflective surfaces directly onto the core of a single-mode fiber (SMF) with a femtosecond laser. FPI 1 is secured to a magnetostrictive material. A single FPI 1 has a sensitivity of 6 pm/mT in the 10–50 mT range, but two cascaded FPIs have a sensitivity of −117.1 pm/mT and an amplification of 19.5. The sensor’s temperature properties are studied, and cross-sensitivity to temperature is eliminated. This sensor is easy to fabricate, compact, simple, and structurally stable, making it highly promising for magnetic field sensing applications.

Frequency Tunable Film Bulk Acoustic Resonator Integrating PMN‐PT/FSMA Multiferroic Heterostructure for Flexible MEMS

AbstractFrequency tunable flexible piezo resonators exhibit significant potential for technological advances in wearable magnetic field sensing, futuristic wireless telecommunication devices, and flexible micro‐electromechanical systems. This study presents a multifunctional and flexible 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3(PMN‐PT)/Ni50Mn35In15 (Ni‐Mn‐In) multiferroic heterostructure‐based bulk acoustic wave (BAW) resonator fabricated over Kapton substrate. The fundamental resonance frequency (fR = 5.31 GHz) of the resonator is tunable with magnetic and electric fields. A significant change in resonance frequency (ΔfR) of 405 MHz has been achieved with 3.37 Hz nT−1 sensitivity using a direct current (DC) magnetic field of 1200 Oe, attributed to the delta‐E effect. The resonator displays a significant magnetic field tunability of 8.83%. Additionally, a substantial ΔfR of 360 MHz, 36 Hz µV−1 sensitivity and 6.78% tunability is attained with 10 V of DC bias voltage. The impact of magnetic field and DC bias voltage on the acoustic characteristics have been studied by fitting the resonance frequency curves with an equivalent modified Butterworth‐Van Dyke model. The fabricated BAW resonator exhibits outstanding flexibility with no discernible change in fR up to 2000 bending cycles. Such PMN‐PT/Ni‐Mn‐In‐based multiferroic BAW resonators displaying magnetic and electric field tunability are propitious for next‐generation flexible electronics and magnetic field sensors.

Fabrication of PVTF Films with High Piezoelectric Properties Through Directional Heat Treatment

Piezoelectric materials can realize the mutual conversion of mechanical energy and electric energy, so they have excellent application prospects in the fields of sensors, energy collectors and biological materials. The poly(vinylidene fluoride) (PVDF)-based polymers have the best piezoelectric properties in the piezoelectric polymer, but they still have a large room for improvement compared with the piezoelectric ceramics. Improving their content of the polar β phase has become a consensus to polish up the piezoelectric performance. Most available studies construct hydrogen bonds or coulomb interactions between the surface of the dopant and molecular chains by doping, which promotes the molecular chains arrangement and thus facilitates the formation of the polar β phase. Recent studies show that the ordered arrangement of molecular chains is also important for piezoelectric properties. At present, the main way to improve the piezoelectric performance of PVDF is through doping or complex heat treatment process. Here, the poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) film was treated by directional heat treatment which used a heating table. Compared with uniform heat treatment like muffle furnace heat treatment, this simple vertical temperature gradient has many advantages for the content of the β phase and the crystallinity of P(VDF-TrFE). The results of the experiment showed that the content of the β phase of films remained at about 88%. When the film thickness was limited to 100 μm and the heat treatment temperature was limited to 200 °C, its crystallinity could reach 75% and the highest piezoelectric coefficient could reach 33.5 ± 0.7 pC/N. P(VDF-TrFE) films based on the experimental methods described above that show great potential for future applications in electronic devices and biomedical applications.

Magnetic field induced anomalous shift of plasmon resonance peak in Al-based plasmon-polariton photodetectors

The influence of magnetic field on Ψ(λ) and Δ(λ) dependences of Al-based plasmon-polariton photodetectors (PPPD) at different magnetic flux densities (100 and 300 mT) and magnetic field directions was investigated. It was obtained that the action of the magnetic field results in the shift of the surface plasmon resonance peak (SPR) position and a change in its intensity. Particularly, in the configuration ( and are collinear) the noted effects were the most pronounced. Additionally, it was found that the magnetic-induced effects are sensitive to the angle of incidence, particularly they enhance with decreasing the angle of incidence. Therefore, they were the most pronounced at the smallest angle in our experiment (20°). The possible physical mechanisms of observed phenomena are discussed. The obtained results can open up new opportunities in the design of optoelectronic sensors of the magnetic field or high-speed optical modulators.

A Low-Cost Ultrasonic Sensor for Online Monitoring of Water Levels in Rivers and Channels

The measurement of flow parameters in rivers and channels is essential for anticipating floods, hydraulic modeling, and conducting water resource management studies. However, the high cost of existing equipment has resulted in a shortage of monitoring stations compared to actual requirements. This research focused on developing and validating a low-cost, highly accurate ultrasonic device that minimizes malfunctions for online monitoring of water levels in channels and streams. Considering the availability of components, cost, and the reported resolution of the product, the GY-Us42 sensor was selected for constructing the level gauge. The sensor operates within a range of 20 cm to 720 cm with a measurement accuracy of approximately 1 mm. The device integrates several error reduction mechanisms to enhance accuracy, including averaging multiple readings and temperature correction techniques. Laboratory data and field data gathered by both staff and shaft encoder were used for device validation. After constructing the main prototype and conducting various tests, multiple devices were installed in different locations within the Tehran rivers, and water depth data were collected over a specific period. Subsequently, data from other field sensors were also collected and used for device validation and accuracy assessment. The results indicate that the device's average error is below 3%, with a Root Mean Squared Error (RMSE) of 5.00 cm during field tests, demonstrates that the constructed device is an efficient tool for measuring water levels in streams, particularly during flood events.

A highly stretchable, self-healing, self-adhesive polyacrylic acid/chitosan multifunctional composite hydrogel for flexible strain sensors

Conductive hydrogels have emerged as excellent candidates for the design and construction of flexible wearable sensors and have attracted great attention in the field of wearable sensors. However, there are still serious challenges to integrating high stretchability, self-healing, self-adhesion, excellent sensing properties, and good biocompatibility into hydrogel wearable devices through easy and green strategies. In this paper, multifunctional conductive hydrogels (PCGB) with good biocompatibility, high tensile (1694 % strain), self-adhesive, and self-healing properties were fabricated by incorporating boric acid (BA) and glucose (Glu) simultaneously into polyacrylic acid (PAA) and chitosan (CS) polymer networks using a simple one-pot polymerization method. Furthermore, the hydrogel strain sensor constructed from the PCGB assembly had great sensing property including high sensitivity (GF = 5.7), durability and stability (5000 cycles). The hydrogel strain sensor was applied to the detection of human motion, which exhibited accurate detection behavior for both large-scale motions and small activities. A strategy to design and fabricate multifunctional conductive hydrogels integrating high stretchability, self-healing, self-adhesion and good biocompatibility was provided, and the multifunctional conductive hydrogels broadened the application of hydrogel-based wearable sensor.

Ultrafast self-healing zwitterionic hydrogels reinforced by carboxymethyl chitosan-oxidized hyaluronic acid and graphene oxide toward high-performance strain sensors

Inspired by the inherent recuperative ability of organisms in nature, researchers have dedicated significant efforts towards developing self-healing hydrogel sensors. Although the works on self-healing hydrogels have made great progress, achieving hydrogel sensors combining with rapid and efficient healing capability, excellent mechanical properties and high sensing sensitivity remains a challenging task. In this study, we proposed a novel approach for fabricating a self-healing conductive zwitterionic hydrogel sensor by adding carboxymethyl chitosan (CMCs) and oxidized hyaluronic acid (OHA) to induce dynamic Schiff base reaction, and nano-reinforced by adding with graphene oxide (GO) nanosheets. This zwitterionic hydrogel exhibited a high tensile strength of 133 kPa and elongation at break of 878 %. By leveraging various dynamic interactions within the system, the hydrogel exhibited ultra-fast and efficient healing property, achieving a self-healing efficiency of 98.9 % within just 15 min. The hydrogel demonstrated exceptional adhesion to diverse substrates especially to glass with a maximum adhesion strength reaching up to 53.7 kPa. The hydrogel exhibited a high gauge factor (GF) value of 23.2, which showed clear and stable monitoring and sensing capabilities across various human movements ranging from swallowing to bending knees. Notably, the hydrogel could also be employed as a Morse code transmitter and flexible tablet. The zwitterionic hydrogel demonstrates its great potential applications in the field of high-performance flexible sensors as well as human-computer interaction.

Lignin-coated liquid metals-induced synthesis of deep eutectic solvent-based hydrogels with environmentally tolerant for strain sensors

In the work, alkali lignin (AL) was used as a coating layer for dispersing liquid metals (LM) in a ternary DES (choline chloride/ethylene glycol/water) system and generating free radical-catalyzed acrylic acid (AA) polymerization. The preparation of flexible sensors had high electrical conductivity (0.33 S·m-1), excellent self-healing and mechanical properties (84.7 KPa). The presence of AL facilitated the dispersion of LM in the DES system and the formation of a flexible hydrogel without the addition of an initiator. Moreover, DES was used as the liquid component of the PAA-AL2@LM2 hydrogel made it more environmentally tolerant and had better water retention. Even at -20 °C, the hydrogel exhibited low electrical resistance (131.4 Ω). The moisture loss of the prepared hydrogel was only 9% after 7 days at room temperature. This work exploited the significant advantages of DES and lignin-based materials in dispersing LM to provide a new technique for the preparation of metal-polymer composite hydrogels, which has great potential in the field of flexible sensors.

Mixed matrix membrane formation with porous metal–organic nanomaterials for CO2 capture and separation: A critical review

Due to the increasingly severe global warming trend, the reduction of CO2 emission and carbon capture have attracted growing interest. The separation of CO2 from gas mixtures, especially from point source and the atmosphere, is considered as one of the most important strategies for mitigating climate change. Porous metal–organic nanomaterials (PNMs), including metal-organic frameworks (MOFs) and metal-organic polyhedra (MOPs) have been extensively investigated in the fields of carbon capture, catalysts, sensors, biomedical imaging and gas storage. Their inherent pores, diverse surface function groups and potential modification possiblities make them competitive carbon capture materials. This review will introduce detailed scientific and technological advancements in PNMs and explain their fitness for carbon capture and separation, followed by the fabrication and application of mixed matrix membranes (MMMs) with PNMs. The current challenges appreared and solutions to improve the MMMs’ CO2 separation performance will also be stressed.

Probe-type optical fiber sensors for electric field distribution measurement

This paper reports a compact fiber optical electric field (E-field) sensor aiming for the precise detection of transient E-field distributions. Here, a reflective polarization-reciprocal optical path is proposed, which inherently mitigates the temperature-induced birefringence interference of the electro-optical crystal without the need for additional optical elements, thereby facilitating a reduced-size sensing probe. Furthermore, an adaptive particle swarm optimization (A-PSO) algorithm has been utilized for the first time to optimize the insulation structure of the optical E-field sensor, which significantly suppresses field distortion within the sensing region by 50%. This method addresses the technical gap in optical E-field sensor structure optimization, providing an effective means to improve its spatial resolution. The experimental results demonstrate that the proposed sensor exhibits a broad response frequency range from 50 Hz to 15 MHz, with a sensitivity of 0.675 V/kV cm−1. The proposed sensor successfully monitors the spatial distribution of electric fields in the lightning interception region of a lightning rod, thereby validating its effectiveness.

Flexible ceramic composites for Magnetic field sensor Applications

Flexible ceramic composites for Magnetic field sensor Applications

Lorentz Force Based Magnetic Field Sensor by Using Heterogeneous Integrated Optical Fiber With Side Nickel Core

Lorentz Force Based Magnetic Field Sensor by Using Heterogeneous Integrated Optical Fiber With Side Nickel Core

Non-contact power system fault diagnosis: a machine learning approach with electromagnetic current sensing

Modern power system protection schemes incorporate artificial intelligence (AI) techniques. However, in a conventional way, most of these schemes rely on the data of current and voltage collected from current transformer (CT) and potential transformer (PT) respectively. CTs suffer from the drawback of core saturation and impact the accuracy and effectiveness of intelligent methods. Also, it has the constraints of size, safety, and economy. The research here explores the effectiveness of magnetic sensors in advanced power system protection schemes as an alternative to traditional current sensing. In the presented work, a novel dataset is prepared by transforming transmission line currents into magnetic field components. Several supervised as well as unsupervised machine learning algorithms have been applied to this data instead of traditional currents and voltage for fault prediction. The paper discusses the comparative evaluation of these algorithms based on various performance metrices which reveals that Gaussian Naïve Bayes (GNB), K-nearest neighbor (KNN), random forest (RF), and extreme gradient boost (XGB) algorithms excel in fault detection, while multilayer perceptron (MLP) and KNN performs better fault classification. The findings promise the potential for developing compact, safe, and cost-effective protection schemes utilizing magnetic field sensors.

Novel Energy-efficient Modified LEACH Routing Protocol for Wireless Sensor Networks

Introduction: In wireless sensor networks (WSNs), hierarchical clustered routing protocols play a crucial role in minimizing energy consumption. The Low Energy Adaptive Clustering Hierarchy (LEACH) architecture is commonly employed for application-specific protocols in WSNs. However, the LEACH protocol may lead to increased energy consumption within the network if the rotational distribution of cluster heads (CHs) is not considered. Methods: A novel average energy, residual energy-based modified LEACH (aerem-LEACH) routing protocol for improving the WSN’s energy efficiency is proposed. This approach simultaneously considers the average energy of the networks and the residual node energy for routing, thereby reducing overall power consumption. Results: The suggested approach in aerem-LEACH accounts for optimal CHs numbers, and nodes in close proximity to the sink are forbidden from participating in cluster formation in order to achieve sufficient performance in the form of reduced sensor node energy consumption. Furthermore, a new threshold is employed in the proposed approach for selecting CHs for the network, and the aerem-LEACH uses free space, multiple hopping, and a hybrid communicating model for an energy-efficient network. Conclusion: The simulation result demonstrates that there is a substantial reduction in the consumption of energy in WSNs with the proposed aerem-LEACH routing protocol compared with existing routing protocols, namely Stable Energy Efficient Network (SEEN), Energy Efficient LEACH (EE LEACH), Optical LEACH (O-LEACH), LEACH-Mobile (LEACH-M), LEACHCentralized (LEACH-C), and LEACH for small-scale as well as large-scale sensor field.

Metamaterials for high-performance smart sensors

In recent years, metamaterials have shown great potential in various fields such as optics, acoustics, and electromagnetics. Sensors based on metamaterials have been gradually applied in daily production, life, and military. Metamaterials are artificial materials with unique properties that ordinary materials do not possess. Through clever microstructure design, they can achieve different properties and have demonstrated significant potential in areas like holographic projection, absorbing materials, and super-resolution microscopy. Sensors are devices that convert external environmental changes into recognizable signals, playing a crucial role in various fields such as healthcare, industry, and military. Therefore, the development of sensors with high sensitivity, low detection limit, wide detection range, and easy integration is of great significance. Sensors based on metamaterials can not only achieve these improvements but also offer advantages like anti-interference and stealth sensing, which traditional sensors lack. These enhancements and new features are significant for the sensor field's development. This article summarizes the benefits of metamaterial sensors in terms of increased sensitivity, expanded detection range, and ease of system integration. It also systematically discusses their applications in various fields such as biomedical and gas sensing. The focus is on the potential applications and development trends of metamaterial-based sensors in the future of human life, providing systematic guidance for the field's advancement.

Gold-coated silver nanorods on side-polished singlemode optical fibers for remote sensing at optical telecommunication wavelengths

The lower refractive index sensitivity (RIS) of plasmonic nanoparticles (NP) in comparison to their plasmonic thin films counterparts hindered their wide adoption for wavelength-based sensor designs, wasting the NP characteristic field locality. In this context, high aspect-ratio colloidal core-shell Ag@Au nanorods (NRs) are demonstrated to operate effectively at telecommunication wavelengths, showing RIS of 1720 nm/RIU at 1350 nm (O-band) and 2325 nm/RIU at 1550 nm (L-band), representing a five-fold improvement compared to similar Au NRs operating at equivalent wavelengths. Also, these NRs combine the superior optical performance of Ag with the Au chemical stability and biocompatibility. Next, using a side-polished optical fiber, we detected glyphosate, achieving a detection limit improvement from 724 to 85 mg/L by shifting from the O to the C/L optical bands. This work combines the significant scalability and cost-effective advantages of colloidal NPs with enhanced RIS, showing a promising approach suitable for both point-of-care and long-range sensing applications at superior performance than comparable thin film-based sensors in either environmental monitoring and other fields.

Quantum theory of a potential biological magnetic field sensor: Radical pair mechanism in flavin adenine dinucleotide biradicals

Recent studies in vitro and in vivo suggest that flavin adenine dinucleotide (FAD) on its own might be able to act as a biological magnetic field sensor. Motivated by these observations, in this study, we develop a detailed quantum theoretical model for the radical pair mechanism (RPM) for the flavin adenine biradical within the FAD molecule. We use the results of existing molecular dynamics simulations to determine the time-varying distance between the radicals on FAD, which we then feed into a quantum master equation treatment of the RPM. In contrast to previous semi-classical models, which are limited to the low-field and high-field cases, our quantum model can predict the full magnetic field dependence of the transient absorption signal. Our model's predictions are consistent with experiments at physiological pH values.

Magnetoelectric effects in a heterostructure of magnetostrictive fiber composite and piezopolymer film

Abstract Magnetoelectric (ME) effects in composite heterostructures comprising ferromagnetic (FM) and piezoelectric (PE) layers realize mutual transformation of magnetic and electric fields and form the basis for the development of highly sensitive magnetic field sensors, electrically tuned electronic components, and energy harvesting devices. ME effects result from a combination of magnetostriction of the FM layer and piezoelectricity in the PE layer due to mechanical coupling between the layers. In this work ME effects are studied in a flexible heterostructure containing a magnetostrictive fiber composite (MFC) and a piezopolymer layer. MFC is a set of microwires made of amorphous FeCoSiB alloy with high magnetostriction and arranged in a plane parallel to each other in a polymer matrix. MFC exhibits strong in-plane anisotropy of magnetization and magnetostriction resulting from demagnetization effects in microwires. Anisotropy leads to the dependence of the linear and nonlinear ME effects characteristics on the orientation of dc magnetic field in the plane of the heterostructure. For the fabricated heterostructure at the resonance frequency of bending vibrations, a linear magnetoelectric coefficient of 24 V/(Oe∙cm) was obtained, and the efficiency of nonlinear generation of the second voltage harmonic reached 1.6 V/(Oe2∙cm). ME effects in MFC heterostructures can be used to create magnetic field sensors and electronics devices that are sensitive to the field orientation.electronics devices that are sensitive to the field orientation.