Multi-parameter Sensor Research Articles

Simultaneous measurement of hydrogen and methane concentrations with temperature self-calibration based on a SPR sensor with an anchor-shaped photonic crystal fiber

Hydrogen and methane are flammable and explosive gases, and their simultaneous measurement holds significant importance in applications of industrial safety and energy transmission. A high-sensitivity multi-parameter sensor based on the surface plasmon resonance (SPR) within an anchor-shaped photonic crystal fiber (AS-PCF) have been proposed and analyzed in detail, which can simultaneously measure hydrogen and methane concentrations while providing temperature self-compensation. To achieve simultaneous detection of hydrogen and methane, an open ring channel is introduced in both the x and y directions of the PCF. Each of these channels is coated with a layer of gold film and gas-sensitive films for hydrogen and methane, respectively. The designed AS-PCF structure is optimized to increase the reactive surface area between the gas and the gas-sensitive films, simultaneously enhancing the energy leakage of core modes to improve sensor performance. In addition, temperature sensitivity is augmented by filling PCF air holes with ethanol and enhancing the asymmetry of the fiber structure. The changes of gas concentration and environmental temperature are derived by demodulating the peak wavelength shifts in the loss and interference spectra. Simulation analysis demonstrates that the sensor can achieve average sensitivities of −0.23 nm/% for hydrogen and −4.84 nm/% for methane within the gas concentration range of 0.5 % to 3 %. Meanwhile, the temperature sensitivity can reach 0.58 nm/°C within the temperature range of 10 °C to 30 °C. This sensor demonstrates excellent linearity and high sensitivity, making it a promising tool for multi-gas measurements in various applications.

Dual-parameter stretchable, transferable mesh piezoresistive sensor for electronic skin detection of strain and temperature changes

Abstract Wearable sensors integrating multiple functions have great potential in artificial intelligence and flexible electronics at this stage and can perceive various external stimuli with high sensitivity and accuracy, such as strain, stress, and temperature. However, because multiple parameters do affect each other and reduce the sensing performance, making a single device that can detect multiple functions simultaneously is a huge challenge. In this paper, a strain-temperature dual-parameter sensor is developed with a planar structure design and used poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) and multi-walled carbon nanotubes polymerization materials to prepare a micron-sized film. The influence of two-dimensional structures on sensing performance is explored through simulation, and a structure with large deformation is selected to improve the strain detection range. The sensor can detect static and dynamic strain signals, and can maintain good linearity and response speed below 100 ms within a large strain range of 20%. In addition, the sensor also exhibits good temperature detection capability, with a temperature sensitivity of 18.2 μV K−1 and the ability to detect static and dynamic temperature changes with long-term stability. Finally, the sensor is tested in some actual scenarios, reflecting that the sensor manufactured has the dual-detection ability, showing sensitive strain monitoring and temperature perception decoupled between the dual signals. The sensor is realized with circuit board acquisition and wireless communication, combining multi-channel applications. Our research provides a feasible method for constructing multi-parameter human-computer interaction sensors.

Multiparameter Sensor Based on Cascaded Micro-Tapered Long-Period Fiber Gratings

Multiparameter Sensor Based on Cascaded Micro-Tapered Long-Period Fiber Gratings

Probe-Type Multi-Core Fiber Optic Sensor for Simultaneous Measurement of Seawater Salinity, Pressure, and Temperature.

In this article, we propose and demonstrate a probe-type multi-core fiber (MCF) sensor for the multi-parameter measurement of seawater. The sensor comprises an MCF and two capillary optical fibers (COFs) with distinct inner diameters, in which a 45° symmetric core reflection (SCR) structure and a step-like inner diameter capillary (SIDC) structure filled with polydimethylsiloxane (PDMS) are fabricated at the fiber end. The sensor is equipped with three channels for different measurements. The surface plasmon resonance (SPR) channel (CHSPR) based on the side-polished MCF is utilized for salinity measurement. The fiber end air cavity, forming the Fabry-Pérot interference (FPI) channel (CHFPI), is utilized for pressure and temperature measurement. Additionally, the fiber Bragg grating (FBG) channel (CHFBG), which is inscribed in the central core, serves as temperature compensation for the measurement results. By combining three sensing principles with space division multiplexing (SDM) technology, the sensor overcomes the common challenges faced by multi-parameter sensors, such as channel crosstalk and signal demodulation difficulties. The experimental results indicate that the sensor has sensitivities of 0.36 nm/‱, -10.62 nm/MPa, and -0.19 nm/°C for salinity, pressure, and temperature, respectively. As a highly integrated and easily demodulated probe-type optical fiber sensor, it can serve as a valuable reference for the development of multi-parameter fiber optic sensors.

A customized drone for ocean and atmospheric measurements and its performances

Drones- Unmanned Aerial vehicles (UAVs)- have become more significant across the world for a wide range of commercial and terrestrial defense applications in recent years. The National Institute of Ocean Technology (NIOT)- Ministry of Earth Sciences (MOES)- is exploring UAVs with a specific focus on maritime applications. NIOT has customized a heavy lift category drone, operable in marine environments and capable of withstanding coastal wind conditions of up to 40 kmph. It can lift and carry an instrumentation payload of 10 kg, conduct ocean data collection, and even take seawater samplings. The 10 kg payload of the UAV might hold a Conductivity Temperature Depth (CTD) sensor, a programmable sea water sampler, and a multi-parameter sensor (MPS) for ocean data collections, and a Light Detection and Ranging (LiDAR) device integrated with a high frame rate camera system for coastal mapping and digital elevation model (DEM) developmental applications. The customized hexacopter UAV is capable of withstanding winds of up to 10 m/s and features a waterproof IPX7 thruster with a maximum thrust of 153 N per axis. The UAV system is also interfaced with a Global Positioning System (GPS), a barometric pressure sensor, a compass, a highly accurate gyroscope, a 15 MP surveillance camera, and an accelerometer sensor connected to a reliable cube orange flight controller module with a redundant 32-bit controller through a serial peripheral interface (SPI). The drone structure and frame is composed of carbon fiber composites to provide an excellent weight-to-strength ratio. This paper presents the outcomes of an initial field test, carried out to ensure the drone’s suitability for various marine applications with intended payloads ranging from 5 - 10 kg weight, including coastal demonstrations and ocean data collections performed at Nellore (Andra Pradesh) and Chennai (Tamil Nadu) coastal waters. Highlights A drone is customised to with stand elevated wind conditions of coastal regions Design is fully flexible meeting the ease of transport from one location to other Highly stable mechanical design to sustain winds of up to 45 KMPH Redundant flight control mechanism is evolved to assure fail safe operations of drone Drone built in with redundant GPS module to avoid scenario like NO Geo-reference at any time Design is type certified and UIN registered with DGCA - India

Addressing data gaps in environmental sensors: a case study on temporal patterns and restoration strategies in East Kazakhstan region

Nowadays, the monitoring systems embedded with diverse sensors within the Internet of Things play an important role in how we collect data and provide in-depth insights into human behavior, environmental trends, and different industrial processes. These sensors can gather data in real-time and due to their ability to connect through various communication interfaces, it is possible to integrate such devices into existing networks ensuring that data can be transmitted in real-time to central systems or mobile devices. However, many factors such as connectivity issues, severe weather, and sensor faults, might cause missing data, thus leading to poor decision-making. In this study, an in-depth analysis was performed on environmental meteorological data collected from May 2022 to March 2023 in the East Kazakhstan region using Vaisala WXT536 multi-parameter weather sensor. The data restoration strategy that is based on the duration of data gaps is evaluated. For short-term gaps under 30 minutes in duration, the mean and median imputation achieved higher results with a root mean squared error of 0.25 for temperature than training Random Forest algorithm which achieved 3.59, while for the extended periods of missing values, the Long Short-Term Memory model was utilized with 2.47 for the temperature. The main goal of the research is to analyze the temporal patterns of missing data and potential reasons for these failures as well as to evaluate the data restoration strategies.

Design of a Multi-Parameter Fusion Sensor and System for Respiratory Monitoring of Mechanically Ventilated Patients in the ICU.

In order to achieve precise respiratory therapy for mechanically ventilated patients, real-time monitoring of the state parameters of inhaled and exhaled gases is required. These parameters are primarily measured by ventilators, with limitations such as insufficient monitoring parameters, circuit leaks, and constraints imposed by distance and obstacles. This paper designs a low-power wireless sensor for multi-parameter monitoring near the patient, which can be used continuously for approximately 60 days. Based on this sensor, an intelligent respiratory monitoring system with a distributed architecture is proposed to achieve intelligent patient-ventilator asynchrony (PVA) perception. Experimental results show that the system can stably and accurately collect and transmit data, with measurement errors for pressure, flow, temperature, humidity, and CO 2 concentration being ±1.3%, ±2.1%, ±0.6° C, ±1% RH, ±0.3 mmHg respectively. The proposed sensor and system have the potential to enhance the efficiency and intelligence of medical care significantly.

Exploring the tuning mechanism of multipolar quasi-continuous domain bound states in tetramer metasurface

High-quality factor (high-<i>Q</i>) resonance has broad prospects in applications such as in narrow-band filtering, slow-light devices, and nonlinear optics interaction enhanced to highly sensitive sensing. Previous methods of designing high-<i>Q</i> resonance suffered intrinsic drawbacks such as high-volume cavities or large-scale bending radii. However, recently, a new approach to designing high-<i>Q</i> resonances has begun to attract public attention on the basis of asymmetric metasurfaces that are related to the bound states in the continuum (BIC) phenomenon. Constructing BIC resonance in electromagnetic metasurface can generate sharp resonant transmission peak. Therefore, there is growing interest in utilizing BIC to achieve metasurface with high-<i>Q</i>. However, most of existing studies are based on single BIC, and few studies focusing on multiband BICs and multiple forms of symmetry breaking. In this work, we propose an all-dielectric metasurface composed of tetrameric cuboids. By etching two elliptical cylinders in each cuboid, the metasurface can simultaneously support in-plane symmetry breaking, displacement perturbations and periodic perturbations. We first use multipole calculations to analyze the physical mechanism by which the metasurface generates quasi-BIC under these three conditions. It is confirmed that the <i>Q</i> factor and resonant peak position of quasi-BIC can be controlled by adjusting the asymmetry parameters. Subsequently, we introduce the in-plane symmetry breaking, displacement perturbations and periodic perturbations into the metasurface simultaneously and generate five quasi-BIC modes, whose numbers and positions can be flexibly adjusted, and the largest <i>Q</i> factor is 58039. In summary, this work provides a new practical design concept for realizing high-<i>Q</i> all-dielectric metasurfaces, which can be used to improve the sensitivity of multi-parameter sensors.

Potential multiparameter sensor based on thin-cladding fiber helical long-period fiber gratings

Potential multiparameter sensor based on thin-cladding fiber helical long-period fiber gratings

Research on multi-parametric sensors based on multi-mode microfiber

Research on multi-parametric sensors based on multi-mode microfiber

Multi-parameter sensor based on dumbbell stepped fiber core structure with the composite interferometric effect

Based on the composite interference structure, fiber optic multiparameter sensors can be constructed, however, this type of sensor has two bottlenecks, which are difficult to fabricate and the parameters interfere with each other. This paper proposes to simultaneously measure force, temperature, and salinity using a compact sensor with minimal signal crosstalk. The sensor structure consists of three cascaded Mach-Zehnder interferometers (MZI). The use of different diameter fiber cores fused together creates a dumbbell Stepped taper-like structure, which ensures that more higher order modes are excited while maintaining the mechanical integrity of the sensor. By creating detecting regions of various sizes, signal interference between parameters is reduced. Theoretical and experimental findings demonstrate that sensors with the dumbbell structure provide a good foundation for three-parameter sensing. and its force, temperature, and salinity sensitivity can reach −2593 dB/N, 53 pm/°C and −145.4nm/RIU. The two bottlenecks mentioned above are effectively resolved by the proposed dumbbell stepped sensor, which may also be applied to multi-parameter measurements for structural health monitoring.

Distributed multi-parameter sensor based on Brillouin scattering in an etched few-mode multi-core fiber

We theoretically propose a unique distributed multi-parameter sensor based on an etched few-mode multi-core fiber (FM-MCF) for simultaneous sensing of temperature, strain, and sample refractive index (SRI). These three parameters can be sensed simultaneously by combining space division multiplexing (SDM) and stimulated Brillouin scattering (SBS). FM-MCF naturally contains an inner core and an outer core, and it is etched until the outer core is exposed. Therefore, the inner core can be employed to calculate the Brillouin gain spectrum (BGS) of LP01 and LP11 through distributed temperature and strain, and the outer core can be used to sense SRI through the BGS of LP01. Note that due to the high corrosion of the outer core, the higher order mode is cut off, so only the LP01 mode can be observed in the outer core. By demodulating the Brillouin frequency shift (BFS) of the BGS in the outer core and the inner core, the proposed sensor has a maximum temperature sensitivity of 1.7220 MHz/°C, a maximum strain sensitivity of 0.0783 MHz/με, and an SRI sensitivity of 274.3245 MHz/RIU around 1.440 RI unit (RIU). Therefore, we show a new perspective for discriminative sensing of multi-parameter in Brillouin distributed sensors based on SDM. The developed multifunctional fiber sensor could find application in the field of environmental sensing, materials science, biomedical applications, and structural health monitoring.

Analyzing the Effectiveness of IOT-Enabled Water Quality Management Systems with Fish Disease Index Parameters – A Critical Review

This research review article examines the effectiveness of Internet of Things (IoT)-enabled water quality management systems in controlling fish diseases. The research conducted a critical review of the literature to analyze the effectiveness of such systems. Through a systematic review of the literature, the authors identified various fish diseases and their associated parameters that are monitored by IoT-enabled water quality management systems. The article then discussed the impacts of various parameters on fish health, and the importance of monitoring these parameters. The authors also highlighted the benefits of using such systems, such as cost-effectiveness, accuracy, and improved data collection and analysis. Finally, the authors proposed various strategies to improve the effectiveness of IoT-enabled water quality management systems, such as the use of multi-parameter sensors, real-time monitoring, and the integration of different sensors to capture a broader range of parameters. In conclusion, the authors argued that IoT-enabled water quality management systems are a cost-effective and accurate way to monitor and manage fish diseases. However, more research is needed to improve the efficiency and accuracy of such systems.

Characterisation of Multi Parameter Sensor for Aero Engine

A multi parameter sensor (Pressure and Temperature) has been developed for use in the harsh environment during aero engine testing. The sensor will be subjected to extreme environmental changes from room temperature and pressure to negative temperature and pressure within a small span of time. It is also very difficult to choose a category of micro behaviors to be characterized among the so many associated with its performance. The multi parameter sensor presented in this paper has been characterized for accuracy, linearity, drift, hysteresis, repeatability, offset and time response. The sensor is intended for applications in the developmental aero engine testing. The evaluation of the performance characteristics carried out in this work is chosen with reference to aero engine testing requirements.

Porous silicon opto-acoustic detector for ternary gas mixture

The use of porous phoxonic crystals with coupled optical and acoustic response has been proposed as a sensing device. Due to the porous nature of the crystal, each layer of the structure can be connected to the environment. As the optical and acoustic performances of the phoxonic crystal change when a gas permeates the pores due to modifications of the effective refractive index and density of the system, it results that these structures are suitable platforms for the detection of gases. The sensor designed following these premises can detect the composition of ternary gas mixtures through optical measurements, while an acoustic wave induces a structural oscillation. The amplified acoustic wave produces a mechanical deformation of the crystal layers that is maximized in the center a resonant microcavity. Therefore, under such experimental conditions, the sensitivity of the optical response is not only due to the optical property changes caused by the gas mixture in contact with the porous structure but also to changes in the mechanical deformations due to modifications of the acoustic properties. In this work, we discuss the device theoretical behavior as a multiparameter sensor that distinguishes the components and concentrations of a ternary gas mixture through the transfer matrix method. For a prototype combination of CO2−Air−CH4 mixture, the estimated resolution of the proposed device fabricated in porous silicon can be has high as 0.05% (500 ppm) in the concentration of each individual species.

Novel Multi-Parametric Sensor System for Comprehensive Multi-Wavelength Photoplethysmography Characterization.

Photoplethysmography (PPG) is widely used to assess cardiovascular health. However, its usage and standardization are limited by the impact of variable contact force and temperature, which influence the accuracy and reliability of the measurements. Although some studies have evaluated the impact of these phenomena on signal amplitude, there is still a lack of knowledge about how these perturbations can distort the signal morphology, especially for multi-wavelength PPG (MW-PPG) measurements. This work presents a modular multi-parametric sensor system that integrates continuous and real-time acquisition of MW-PPG, contact force, and temperature signals. The implemented design solution allows for a comprehensive characterization of the effects of the variations in these phenomena on the contour of the MW-PPG signal. Furthermore, a dynamic DC cancellation circuitry was implemented to improve measurement resolution and obtain high-quality raw multi-parametric data. The accuracy of the MW-PPG signal acquisition was assessed using a synthesized reference PPG optical signal. The performance of the contact force and temperature sensors was evaluated as well. To determine the overall quality of the multi-parametric measurement, an in vivo measurement on the index finger of a volunteer was performed. The results indicate a high precision and accuracy in the measurements, wherein the capacity of the system to obtain high-resolution and low-distortion MW-PPG signals is highlighted. These findings will contribute to developing new signal-processing approaches, advancing the accuracy and robustness of PPG-based systems, and bridging existing gaps in the literature.

Potential of a Miniature Spectral Analyzer for District-Scale Monitoring of Multiple Gaseous Air Pollutants.

Gas sensors that can measure multiple pollutants simultaneously are highly desirable for on-site air pollution monitoring at various scales, both indoor and outdoor. Herein, we introduce a low-cost multi-parameter gas analyzer capable of monitoring multiple gaseous pollutants simultaneously, thus allowing for true analytical measurement. It is a spectral sensor consisting of a Fourier-transform infrared (FTIR) gas analyzer based on a mid-infrared (MIR) spectrometer. The sensor is as small as 7 × 5 × 2.5 cm3. It was deployed in an open-path configuration within a district-scale climatic chamber (Sense City, Marne-la-Vallée, France) with a volume of 20 × 20 × 8 m3. The setup included a transmitter and a receiver separated by 38 m to enable representative measurements of the entire district domain. We used a car inside the climatic chamber, turning the engine on and off to create time sequences of a pollution source. The results showed that carbon dioxide (CO2) and water vapor (H2O) were accurately monitored using the spectral sensor, with agreement with the reference analyzers used to record the pollution levels near the car exhaust. Furthermore, the lower detection limits of CO, NO2 and NO were assessed, demonstrating the capability of the sensor to detect these pollutants. Additionally, a preliminary evaluation of the potential of the spectral sensor to screen multiple volatile organic compounds (VOCs) was conducted at the laboratory scale. Overall, the results demonstrated the potential of the proposed multi-parameter spectral gas sensor in on-site gaseous pollution monitoring.

Multi-parameter sensing of transverse stress for haptic perception based on side-polished chirped fiber Bragg grating with mutual correlation demodulation

The detection of milli-newton level stress, such as its magnitude and location, are the most important for haptic perception. Here, a multi-parameter stress sensor based on a side-polished chirped fiber Bragg grating (SCFBG) with mutual correlation demodulation is proposed, which can be used to measure the magnitude, the location of the point stress and the width of the plane stress. The stress on the SCFBG produces a longitudinal strain across the whole length of the SCFBG, which results in a wavelength shift in the SCFBG's spectrum. A mutual correlation demodulation is proposed to accurately calculate the wavelength shift of different wavelengths in the reflection spectrum of the SCFBG. According to the wavelength shift, the magnitude of the stress is obtained. At the same time, the effective refractive index at the stress point will change, resulting in an attenuation dip and an enhancement dip at the corresponding wavelength. The location of the stress point can be calculated through the attenuation dip. Additionally, under the action of plane stress, the geometrical width of the contacting surface can be calculated through the wavelength difference of the two attenuation dips. Experimental results show that under the stress range of 0 to 100 mN, for the length of 44 mm SCFBG, the stress sensitivity of 0.01 nm/mN, spatial resolution of 0.1 mm and location sensitivity of 0.88 nm/mm are obtained. The relative errors of the stress magnitude, location and geometrical width are 0.82%, 0.90% and 0.20%, respectively.

Simultaneous measurement three parameters of temperature, strain, and curvature by thin-core fiber based-Mach-Zehnder interferometer

A Mach-Zehnder interferometer (MZI) sensor for simultaneous measurement of three parameters is developed. The sensor structure is spliced by single-mode fiber, no-core fiber, thin-core fiber (TCF) and single-mode fiber in turn, where the sensing element is TCF. Due to the different core diameters of three types of optical fibers, the light in the transmission process excites a number of higher-order modes and interacts to form a mode interferometer. The interference spectrum produces many resonance peaks that are sensitive to different parameters. We select three resonant peaks sensitive to temperature, strain and bending for measuring temperature, strain and curvature. The experimental results display that the resonant wavelength of the sensor transmission spectrum drifts linearly as a function of the environmental parameters, with a maximum sensitivity of 248.7 pm/℃ for temperature, −2 pm/με for strain and −24.784 nm/m−1 for curvature. Selecting three resonance peaks to construct a measurement matrix realizes three-parameters simultaneous measurement and eliminates the cross-sensitivity among the three physical quantities. In addition, the proposed sensor possesses appealing characteristics of facile manufacturing process, compact size, high sensitivity, good linear fitting, robustness and low cost, and the sensor has a broad application prospect in the field of multi-parameter simultaneous measurement. In short, only one MZI in the optical fiber can realize the simultaneous monitoring of temperature, strain and bending, which provides a new solution for creating a compact multi-parameter sensor for structural health monitoring.

Directional Bending Sensor and Multiparameter Sensor Based on D-Core Multimode Fiber

For the sensor with interference between fiber core mode and cladding mode, the directional bending sensor can be realized by processing asymmetric structure on the cladding or using eccentric fiber, but the temperature and strain crosstalk of the sensor with interference between fiber core mode and cladding mode is large. In this article, a kind of fiber intermode interference sensor with asymmetric structure is proposed, which can realize vector bending sensing and reduce temperature and strain crosstalk. The designed D-core multimode fiber has cladding and air on both sides of the fiber core. When 0° and 180° bending are applied to it, the interference spectrum moves in different directions, thus realizing the recognition of bending direction. For curvature detection, in the curvature range of 0–0.62 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{-{1}}$ </tex-math></inline-formula> , the sensitivity of 0° bending is 11.00 nm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{-{1}}$ </tex-math></inline-formula> , and that of 180° bending is −11.40 nm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{-{1}}$ </tex-math></inline-formula> . For liquid level detection, the sensing sensitivity is 234 pm/mm with the range of 0–4 cm, and the linearity is 0.993. In addition, the temperature sensitivity is as low as 10 pm/°C, and the strain sensitivity is as low as −1.28 pm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> . The proposed sensor realized the directional bending sensing and liquid level sensing of intermodal interference. Its low sensitivity to temperature and strain can be used to avoid the cross-sensitivity problems. In the field of water flow detection, the simultaneous detection of water level and water flow direction can be realized by the proposed sensor.