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The use of hydrogen as fuel presents many safety challenges due to its flammability and explosive nature, combined with its lack of color, taste, and odor. The purpose of this paper is to present an electrochemical sensor that can achieve rapid and accurate detection of hydrogen leakage. This paper presents both the component elements of the sensor, like sensing material, sensing element, and signal conditioning, as well as the electronic protection and signaling module of the critical concentrations of H2. The sensing material consists of a catalyst type Vulcan XC72 40% Pt, from FuelCellStore, (Bryan, TX, USA). The sensing element is based on a membrane electrode assembly (MEA) system that includes a cathode electrode, an ion-conducting membrane type Nafion 117, from FuelCellStore, (Bryan, TX, USA). and an anode electrode mounted in a coin cell type CR2016, from Xiamen Tob New Energy Technology Co., Ltd, (Xiamen City, Fujian Province, China). The electronic block for electrical signal conditioning, which is delivered by the sensing element, uses an INA111, from Burr-Brown by Texas Instruments Corporation, (Dallas, TX, USA). instrumentation operational amplifier. The main characteristics of the electrochemical sensor for hydrogen leakage detection are operation at room temperature so it does not require a heater, maximum amperometric response time of 1 s, fast recovery time of maximum 1 s, and extended range of hydrogen concentrations detection in a range of up to 20%. [ABSTRACT FROM AUTHOR]

Background. The article is devoted to the development of constructive and technological methods for ensuring the temporal and parametric stability of films and film structures formed on metal–film sensors of physical quantities. The relevance of the presented materials lies in the fact that the stability of sensors depends to a greater extent on the stability of resistive films and film structures. The purpose of the article is to develop reproducible designs and technologies that ensure the formation of time-stable sensor elements and structures. Materials and methods. The article describes in sufficient detail the proposed designs of polyfilm strain-resistant structures of various configurations. Mathematical models of multilayer film structures are considered and analyzed, the nominal values of strain gages are determined, and methodformation are determined. In particular, an increase in the accuracy and consistency of the electrophysical characteristics of the sensing elements and measuring modules was achieved by 30–40 % compared with well-known Russian sensors.s for minimizing the temperature coefficients of resistive structures are determined. Results and conclusions. As a result of the research conducted in the field of developing methods for regulating and maintaining the temporal and parametric stability of sensor characteristics, the designs of polyfilm structures and methods of their

Background. The paper investigates the sensing element of a capacitive pressure sensor based on a silicon corrugated membrane. Materials and methods. Using finite element modeling, the parameters of the corrugation were determined, which make it possible to double the sensitivity compared to a flat membrane having similar overall dimensions. Results and conclusions. It is shown that the presence of an edge corrugation with a rectangular profile makes it possible to increase the sensitivity of the membrane.

Introduction. At present, acceleration sensors are in demand in various areas, from consumer electronics to space technology. Microaccelerometers exhibit the advantages of compact dimensions, light weight, and ease of integration with other components. The most common accelerometers are based on microelectromechanical systems. However, due to the fragility of elastic suspensions, these devices are characterized by low impact resistance, which impedes their application in highly dynamic objects with accelerations of up to 50 000 g. The authors propose to use microaccelerometers based on surface acoustic waves, which are solid-state monolithic structures capable of withstanding high shock loads. Previous work has proposed the concept of concentric electrodes, which are more energy efficient compared to linear designs. However, concentric elements are difficult to connect to the electrical circuit, due to the impossibility of connecting the busbars directly. Therefore, the authors describe and simulate five alternative methods for connecting the sensing element of such devices.Aim. To select an optimal method for connecting the sensing element of microaccelerometers from the standpoint of maintaining the integrity of the electrodes and ensuring minimal influence on the propagation of surface acoustic waves.Materials and methods. Finite element simulation in the COMSOL Multiphysics software.Results. Five connection methods, including point-to-point wiring, removing the electrode sector, filling holes in the electrodes and substrate with metal, pulling wires through holes in the substrate and bringing out contact bars along the side face, were proposed and analyzed. Computer simulation was carried out. Graphs of the amplitude-frequency characteristic are presented.Conclusion. Among the considered methods for connecting the sensing element, the most appropriate seems to be method No. 3, which implies holes in the electrodes and contacts on the bottom side of the substrate. Here, the graph of the amplitude-frequency characteristic practically coincides with that of the sensor without connections (reference). Future work will focus on creating a prototype and its experimental testing.

This study proposes a dual-functional terahertz device based on the Dirac semimetal, serving as both a sensing element and a band-pass filter. The device's operating mode can switch between these two functions by utilizing the phase transition property of vanadium dioxide (VO2). When VO2 is in the insulating state, the device functions as a sensing element. The simulation results demonstrate an impressive refractive index sensitivity of 374.40 GHz/RIU (Refractive Index Unit). When VO2 is in the metallic state, the device functions as a band-pass filter, exhibiting a center frequency of 2.01 THz and a 3 dB fractional bandwidth of 0.91 THz. The integration of these dual functionalities within a single terahertz device enhances its utility in both sensing and filtering applications. [ABSTRACT FROM AUTHOR]

Background. Vibration measurement is one of the most popular and cost-effective methods of diagnosing the overall condition of equipment and is of undeniable importance in modern technology. Thanks to this process, manufacturers and consumers can be sure of the reliability and quality of technical systems, as well as prevent possible breakdowns and failures. And the wide scope of vibration measurements in various fields confirms their versatility and importance in modern technical progress. The purpose of measuring the effects of critical temperatures on a temperature transducer is to determine how a change in critical temperature can affect the accuracy and reliability of the transducer. This will improve the quality of temperature measurement, eliminate inaccuracies and errors in equipment performance, and increase the efficiency of the equipment in various operating conditions. Materials and methods. The research method in this paper is a simulation model of the sensor, which is used to test for vibration and exposure to critical temperatures. Ansys and SolidWorks Simulation software are used to create the model to avoid costly and time-consuming test cycles. Results. As a result of the simulation modeling, the epuples of mechanical stress distribution under sinusoidal vibration and the epuples of temperature distribution under critical temperatures were constructed.

Introduction. Modern mobile control objects require the use of highly sensitive transducers of motion parameters, e.g., acceleration, with a wide measurement range. Increased sensitivity to measured parameters can be achieved by using precision optics, e.g., based on the tunneling effect. However, operating ranges of induced movements are less than a micrometer, which creates difficulties in positioning the sensing element. In order to improve manufacturability, to extend the measurement range and to reduce errors of acceleration transducers with optical tunneling, compensation circuits with a piezoelectric actuator as an active sensor can be used.Aim. To extend the measurement range of microelectromechanical acceleration transducers through the use of an integrated approach, including the introduction of a compensation circuit for sensor movements based on the inverse piezoelectric effect and detection of these movements by optical means.Materials and methods. An approach to compensating sensor movements is proposed. This approach consists in using a bimorph piezoelectric plate as an inertial element. The use of optical reading of sensor sub-micrometer displacements is considered.Results. A block scheme and a functional scheme of a compensator micro-opto-electromechanical acceleration transducer with a bimorph piezoelectric sensing element are developed. Deformations in the sensing element under the influence of accelerations (up to 100 m/s2) and compensation voltages, whose amplitude does not exceed several volts, are investigated to ensure the possibility of using the optical tunneling effect in the proposed transducer.Conclusion. A mathematical model of the transducer was developed and studied. A 2.5-fold increase in the measurement range was achieved. It was shown that the introduction of compensation feedback does not decrease the permissible frequency range of measured accelerations.

A photocurable resin/carbon nanotube (CNT) nanocomposite was fabricated from aligned CNTs in an acrylic matrix. The conductivity of the nanocomposite increased rapidly and then stabilized when the CNT content was increased up to and beyond the percolation threshold. Various structures were created using a digital light processing (DLP) 3D printer. Various polymeric dispersants (SMA-amide) were designed and synthesized to improve the CNT dispersion and prevent aggregation. The benzene rings and lone electron pairs on the dispersant interacted with aromatic groups on the CNTs, causing the former to wrap around the latter. This created steric hindrance, thereby stabilizing and dispersing the CNTs in the solvent. CNT/polymer nanocomposites were created by combining the dispersant, CNTs, and a photocurable resin. The CNT content of the nanocomposite and the 3D printing parameters were tuned to optimize the conductivity and printing quality. A touch-based human interface device (HID) that utilizes the intrinsic conductivity of the nanocomposite and reliably detects touch signals was fabricated, enabling the free design of sensors of various styles and shapes using a low-cost 3D printer. The production of sensors without complex circuitry was achieved, enabling novel innovations. [ABSTRACT FROM AUTHOR]

Among piezo composites, 0–3 type ceramic/polymer-based composites have balanced properties and flexible manufacturing processes, allowing them to tackle challenges in wearable electronics and sensing technology. However, due to a misfit between the dielectric coefficients of the ceramic particles and polymer matrix, poling 0–3 composites is difficult. Therefore, in this study, we develop a novel poling method that combines the merits of normal corona poling and oil-based poling methods to activate a lead zirconium titanate (PZT)/Polyethylene glycol diacrylate (PEGDA) composite. The influence of various parameters (voltage, temperature, poling duration, and time of ageing) on the piezoelectric and dielectric properties of the PZT/polymer composite were evaluated. For the 0–3 PZT/PEGDA composites (67 wt%), the optimal poling parameters were found to be 60 min poling duration, 25 °C, and 24 kV. The d 33 (32 pC/N) obtained by the proposed poling method is about 3 times that obtained by the normal corona poling method (11 pC/N). This modified poling method was shown to be more effective than the conventional method for a range of filler contents (50 wt%, 67 wt%, and 75 wt%). It was also found that the d 33 value of the PZT/PEGDA composite increased over time and was attributed to the increase of the composite dielectric constant after poling. Finally, sensing elements were assembled from the poled samples and evaluated, which shows the potential for detecting tiny signals in sensing and soft robotics. [ABSTRACT FROM AUTHOR]

Background. At present, the efficiency of development and operation of modern automated systems of control and management of various technological processes is largely determined by the technical and economic characteristics of the primary transducers of information (sensors) among which the important place belongs to displacement sensors. The mathematical model of mutual inductive linear displacement sensors underlying the calculation algorithm developed on the basis of the solution of the boundary electrodynamic problem of interaction of a homogeneous alternating field with an electromagnetic rod is considered. Materials and methods. The systems of Poisson's and Laplace's equations with respect to the vector potential were used in this work. Results. As a result of this research, a mathematical model was proposed, which was used in the development of the TDS designed to measure the movements of the solar panels of a satellite vehicle in open space conditions.

The aim of this work is to propose two different and integrated sensors for the structural health monitoring of concrete beams. In particular, a diffused sensing element and a split ring resonator network are presented. The first sensor is able to detect the variations in the dielectric properties of the concrete along the whole beam length, for a diffuse monitoring both during the important concrete curing phase and also for the entire life cycle of the concrete beams. The resonators instead work punctually, in their surroundings, allowing an accurate evaluation of the permittivity both during the drying phase and after. This allows the continuous monitoring of any presence of water both inside the concrete beam and at points that can be critical, in the case of beams in dams, bridges or in any case subject to a strong presence of water which could lead to deterioration, or worse, cause serious accidents. Moreover, the punctual sensors are able to detect the presence of cracks in the structure and to localize them. [ABSTRACT FROM AUTHOR]

Measurements of magnetic field parameters are the basis of all magnetic measurements. Most methods of measuring magnetic field parameters are based on force (energy) interaction of magnetic field with macro- or microscopic currents and electromagnetic induction. The paper considers the possibility of constructing a magnetic field strength gradient meter based on the absolute helical instability of electron-hole plasma of a semiconductor sample. The functional scheme of the gradiometer and the results of experimental and theoretical studies of the sensitive element of the gradiometer are presented.

A tri-axial stress sensor was designed to measure contact stresses in the tire–pavement contact patch. The shape and size of the sensor surface were designed considering both the asphalt pavement texture and the tire pattern. The top-down cracking mechanism was also taken into account, and the sensor was placed at the vertical crack depth. Temperature drifts and zero drifts were compensated for. The sensor had high structural strength and met the sensing requirements of specialized heavy vehicles. In a preliminary study, three sensors were fabricated and calibrated in three directions. Simulated measurements were performed using a tire–pavement surface contact test bench. Signals from the L-shaped sensor region were obtained for the upper, middle, and lower parts of the tire, and preliminary stress distributions were determined at different positions on the contact surface. This study has laid a foundation for the design and construction of a more precise test system in the future. [ABSTRACT FROM AUTHOR]

Modern and perspective tasks of robotics with control from artificial intelligence systems require the use of small-sized measuring devices. In this case, the intensively developed quantum sensors and quantum computers have a bright prospect. Their main advantage is the ability to successfully process the data of random processes with decomposition of complex functions into simple multipliers, as well as their small size and the ability to transmit data over long distances without wires. Data transmitted over quantum communication lines cannot be copied or intercepted, which is very useful for remote control of complex technical systems. Based on the results of the analysis of probabilistic noisy data quantum computer is able to quickly develop an assessment of the technical condition of the complex system. At the same time, there is no need to go through all the possible solutions to the evaluation problem with a huge amount of input data, some of which can sometimes be undefined. The main problem in the research of quantum processes is that researchers study the processes occurring in materials, but they do not indicate the ways in which quantum sensors and quantum computers are used in practical applications. This article explains how to form a measuring transformer that will be compatible with a quantum computer. The main objective of the study was to bring the results of basic research in the field of quantum computing closer to their application in applied tasks. It is shown how quantum processes can be shifted to the field of technical measurements of physical quantities used in complex systems. In the process of obtaining the results of the study, the hypothetical deductive method and the method of ascent from the abstract to the concrete within the framework of a systematic approach to the development of elements of technical systems were used. The result is a description of the processes of designing of tension sensing element made of modified diamond. The main findings of the study include the fact that quantum sensors implemented in the form of a modified diamond crystal are well described by the theory of measuring transducers with frequency output and can be used to get data about the state of an object.

The article provides a comparative analysis of multi-element sensors of an electric field of a flat shape differing in various configurations of sensitive elements, each of which is determined by its design parameters. For this, a generalized mathematical model of the sensor is compiled taking into account its design parameters which affect the error from field inhomogeneity and the spatial range of measurement. Using a generalized mathematical model, graphs of the sensor error are constructed depending on the spatial measurement range and various design parameters of its sensitive elements. The change in design parameters allowed us to model sensitive elements in the form of quadrants and truncated quadrants of a circle. According to the error graphs, it is established that sensitive elements made in the form of quadrants of a circle provide the sensor with a lower error and a larger spatial range of measurement, therefore their use is more appropriate. The studies performed allowed us to obtain the following technical results. Sensors with sensitive elements in the form of a quadrant of a circle have a minimum of an error and a maximum of a spatial range of measurement at design parameters: b = 0 and b0 = 0,2; b = 0 and b0 = 0.4, for which, with a maximum spatial range of measurement equal to unity (a = 1), the errors are respectively minus 3 % and minus 10 %.

Continuous measurement of temperature profiles on the human body surface provides handy information for the diagnosis and as a beneficial guide to take appropriate action. A textile based Resistance Temperature Detector (RTD) has been reported recently, which could be exploited to monitor the temperature of human body over extended period of time. For the purpose of calibrating these textile based sensor, a tailor-made test rig has been developed. The working principle of this sensing fabric is the same as the RTD i.e. change in resistance because of change in temperature. Validation of experimental results by modelling was one of the prime objectives of this study. This paper reports the steady state mathematical model of the test rig components, by the application of fundamental heat transfer principles. It was concluded that the temperature varies linearly across the thickness of textile based temperature sensor in a rig setting while the temperature of the sensing element of textile based temperature sensor could be approximated by knowing its exact position within the fibrous structure. This input would be helpful for the calibration purpose of the sensor samples in an improved manner and to circumvent the individual testing and repetition of experiments on a test rig. [ABSTRACT FROM AUTHOR]

Inorganic piezoelectric ceramic composite is the potential sensing element for long-term structural health monitoring due to its excellent durability and compatibility. In this study, a Ceramicrete-based piezoelectric composite is proposed preliminarily, in which the magnesium potassium phosphate cement is used as the matrix and the lead zirconate titanate particle is utilized as the functional phase. Piezoelectric properties test and microstructure analysis are performed to evaluate the testing samples. Results show that the piezoelectric performance of the composite increase with the increase of piezoelectric ceramic particle size. The value of the piezoelectric strain factor (d 33) can reach 83.8 pC/N, while the corresponding piezoelectric voltage factor (g 33) is 50.1 × 10-3 V•m/N at the 50th day after polarization. Microstructure analysis illustrates that the interfacial transition zone (ITZ) between the matrix and the particles is dense. Moreover, the influence of aging on the composite is attributed to the continuous hydration after polarization. It indicates that the composites have a higher piezoelectric performance, which can be regarded as a promising sensing element material. [ABSTRACT FROM AUTHOR]

In aviation measurement of static and total pressure is widely used to determine the flight conditions. Results of pressure measurements are used to monitor flight attitude, equivalent speed, Mach number, vertical velocity etc. The algorithm for data acquisition and processing for developed pressure measurement system is presented in this paper.

Compatibility, a critical issue between sensing material and host structure, significantly influences the detecting performance (e.g., sensitive, signal-to-noise ratio) of the embedded sensor. To address this issue in concrete-based infrastructural health monitoring, cement-based piezoelectric composites (piezoelectric ceramic particles as a function phase and cementitious materials as a matrix) have attracted continuous attention in the past two decades, dramatically exhibiting superior durability, sensitivity, and compatibility. This review paper performs a synthetical overview of recent advances in theoretical analysis, characterization and simulation, materials selection, the fabrication process, and application of the cement-based piezoelectric composites. The critical issues of each part are also presented. The influencing factors of the materials and fabrication process on the final performance of composites are further discussed. Meanwhile, the application of the composite as a sensing element for various monitoring techniques is summarized. Further study on the experiment and simulation, materials, fabrication technique, and application are also pointed out purposefully.

This work shows the possibility of using arrays of ZnO nanorods grown on a glass substrate as a sensitive element for measuring air flow velocity. Since oxide semiconductors have a temperature dependence of resistance, a theoretical and experimental assessment was made of the influence of air velocity on the increase in resistance of a sensitive element. It has been theoretically shown that when air is blown through, the temperature of the free end of the ZnO nanorod can decrease by several degrees. An experimental evaluation showed that when gas is blown at a speed of 12.5 cm/s, the resistance of the sensing element increases by about 20%, which is equivalent to a temperature increase of about 4 degrees. In addition, it was found that the dependence of the increase in the resistance of the sensitive element when exposed to an air flow from 0 to 12.5 cm / s is close to linear.

The silicon micromechanical gyroscope, which will be introduced in this paper, represents a novel MEMS gyroscope concept. It is used for the damping of a single-channel control system of rotating aircraft. It differs from common MEMS gyroscopes in that does not have a drive structure, itself, and only has a sense structure. It is installed on a rotating aircraft, and utilizes the aircraft spin to make its sensing element obtain angular momentum. When the aircraft is subjected to an angular rotation, a periodic Coriolis force is induced in the direction orthogonal to both the angular momentum and the angular velocity input axis. This novel MEMS gyroscope can thus sense angular velocity inputs. The output sensing signal is exactly an amplitude-modulation signal. Its envelope is proportional to the input angular velocity, and the carrier frequency corresponds to the spin frequency of the rotating aircraft, so the MEMS gyroscope can not only sense the transverse angular rotation of an aircraft, but also automatically change the carrier frequency over the change of spin frequency, making it very suitable for the damping of a single-channel control system of a rotating aircraft. In this paper, the motion equation of the MEMS gyroscope has been derived. Then, an analysis has been carried to solve the motion equation and dynamic parameters. Finally, an experimental validation has been done based on a precision three axis rate table. The correlation coefficients between the tested data and the theoretical values are 0.9969, 0.9872 and 0.9842, respectively. These results demonstrate that both the design and sensing mechanism are correct.

This article considered method to measure low-frequency angular oscillations of rotors of electric machines and solved the problem of assess shear deformations of rotating shafts in transient conditions. Method of calculating torsional torques is considered by the example of electric generator shaft of diesel generator unit. This method allows taking into account the angular deformations of the rotating shafts, and reducing vibration overloads, and increasing in both resource and reliability. [ABSTRACT FROM AUTHOR]

The influence of birefringence fibre (BF) loop mirror (Bi‐FLM) length on the light intensity sensitivity to strain was analysed theoretically and investigated experimentally. The same type of BF but the different length was chosen as the sensing element to be glued to the test object. The relationship between the light intensity and strain was obtained for the Bi‐FLM with different BF length. Afterwards, the light intensity signals were converted into voltage signals. The influence of BF length on the average voltage sensitivity to strain was investigated experimentally. The experimental results indicate that the Bi‐FLM with a long BF has a high average voltage sensitivity to strain but a small strain measurement range, while the Bi‐FLM with a short BF has a low average voltage sensitivity to strain but a large strain measurement range. From the experiments carried out, it was seen that the average voltage sensitivity to strain can be improved by increasing the BF length. This method does not increase the system complexity. [ABSTRACT FROM AUTHOR]

Metallic multilayer spin-valve nanostructures that comprise the exchange-coupled ferromagnet/ Ru/ferromagnet structure in the free layer have been synthesized by magnetron sputtering. For microobjects (meanders) formed from CoFe/Cu/CoFe/Ru/CoFe/FeMn/Ta spin valves with different thicknesses of ruthenium and copper layers, the dependences of the magnetoresistive sensitivity and low-field hysteresis loop shift on the meander strip width have been studied. Sensing elements characterized by high magnetoresistive sensitivity have been manufactured. [ABSTRACT FROM AUTHOR]

The authors have recently developed a time‐domain reflectometry (TDR)‐based leak‐localisation system which, being based on an electromagnetic technique, overcomes the well‐known downsides (sensitivity to environmental noise, to pipe material and geometry etc.) of traditional, electro‐acoustic leak‐localisation techniques. Starting from the positive results obtained so far, in this work, the authors investigate the possibility of implementing an integrated TDR/ground penetrating radar (TDR/GPR) approach. The TDR would allow the preliminary leak localisation, while the GPR technique would be used to have a countercheck for possible false positives. Also, GPR would allow to assess the quantity of the leaked water (thus scheduling a priority order for repair) and to obtain a three‐dimensional view of the subsurface soil around the pipes, so as to assess their health status. In this work, the combined TDR/GPR approach is tested on a pipe section in the presence of two leaks. In addition to this, in this study, also a different configuration of the TDR sensing element (SE) is experimented. As described in what follows, this new SE configuration is expected to expedite considerably the implementation and the use of the TDR‐based leak detection system. [ABSTRACT FROM AUTHOR]

In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 μs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors. [ABSTRACT FROM AUTHOR]

In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R2 ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system. [ABSTRACT FROM AUTHOR]

In this paper, an electronic tongue/taste sensor array containing different interdigitated capacitor (IDC) sensing elements to detect different types of tastes, such as sweetness (glucose), saltiness (NaCl), sourness (HCl), bitterness (quinine-HCl), and umami (monosodium glutamate) is proposed. We present for the first time an IDC electronic tongue using sensing membranes containing solvatochromic dyes. The proposed highly sensitive (30.64 mV/decade sensitivity) IDC electronic tongue has fast response and recovery times of about 6 s and 5 s, respectively, with extremely stable responses, and is capable of linear sensing performance (R2 ≈ 0.985 correlation coefficient) over the wide dynamic range of 1 μM to 1 M. The designed IDC electronic tongue offers excellent reproducibility, with a relative standard deviation (RSD) of about 0.029. The proposed device was found to have better sensing performance than potentiometric-, cascoded compatible lateral bipolar transistor (C-CLBT)-, Electronic Tongue (SA402)-, and fiber-optic-based taste sensing systems in what concerns dynamic range width, response time, sensitivity, and linearity. Finally, we applied principal component analysis (PCA) to distinguish between various kinds of taste in mixed taste compounds. [ABSTRACT FROM AUTHOR]

In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 µM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance. [ABSTRACT FROM AUTHOR]

The basic characteristics of developed nanosensors of liquefied petroleum gas (LPG) vapors are submitted. The applicability of these devices in explosion and fire safety systems of LPG producing, storing, and utilizing facilities is analyzed. [ABSTRACT FROM AUTHOR]

Nanosensors of liquefied petroleum gas (LPG) vapors are systemized according to design features of their sensing elements. Three groups of these devices are distinguished. Brief accounts about a few nanosensors are given. [ABSTRACT FROM AUTHOR]

This study presents a microcontroller‐based instrumentation system to measure the refractive index (RI) of an unknown liquid using an optical fibre sensor probe. A bare, tapered and bent multi‐mode optical fibre (BTBMOF) is used as the sensing element or refractometer to construct an optical fibre sensor probe. The optical fibre sensor probe contains (i) a diode laser as source (with a pigtail), (ii) a BTBMOF as sensing element and (iii) an LDR (light dependent resistor) as detector. The bare and tapered portion of the optical fibre sensor is given the shape of a semicircular arc to add the macro bending effect along with the power coupling effect (which takes place because of propagation of a light ray through the tapered portion of the fibre). The diode laser source launches a beam of laser ray at one end of the BTBMOF. The power transmitted through the BTBMOF is influenced by the RI of the liquid surrounding it. The laser beam coming out from the BTBMOF is made incident on the LDR. Thus, the resistance of the LDR changes according to the RI of the liquid applied around the BTBMOF. The LDR is connected across a 5 V DC supply with a series resistance to form a potential divider circuit. The output from the potential divider circuit is interfaced to the ADC0 (analogue input pin) of an ATmega 32 microcontroller via a low‐pass filter for reading and displaying the RI value of the liquid. [ABSTRACT FROM AUTHOR]

Received nanostructure of the composite film allows to create integrated sensor controls of humidity with high sensitivity, stable in time, with linear dependence of capacity from relative humidity practically in all range of its change (3 to 100%) and keeping working capacity at low temperatures up to –35°С.

Polyvinylidene fluoride (PVDF) and AgNO3/PVDF composite piezoelectric fibers were prepared using near-field electrospinning technology. The prepared fibers are attached to the electrode sheet and encapsulated with polydimethylsiloxane to create an energy acquisition device and further fabricated into a dynamic sensing element. The addition of AgNO3 significantly increased the conductivity of the solution from 40.33 μS/cm to 883.59 μS/cm, which in turn made the fiber drawing condition smoother with the increase of high voltage electric field and reduced the fiber wire diameter size from 0.37 μm to 0.23 μm. The tapping test shows that the voltage signal can reach ~0.9 V at a frequency of 7 Hz, and the energy conversion efficiency is twice that of the PVDF output voltage. The addition of AgNO3 effectively enhances the molecular bonding ability, which effectively increases the piezoelectric constants of PVDF piezoelectric fibers. When the human body is exercised for a long period of time and the body is overloaded, the biceps muscle is found to produce 8 to 16 tremors/second through five arm flexion movements. The voltage output of the flexible dynamic soft sensor is between 0.7–0.9 V and shows an orderly alternating current waveform of voltage signals. The sensor can be used to detect muscle tremors after high-intensity training and to obtain advance information about changes in the symptoms of fasciculation, allowing for more accurate diagnosis and treatment. [ABSTRACT FROM AUTHOR]