scholarly journals A Gas Mixture Prediction Model Based on the Dynamic Response of a Metal-Oxide Sensor

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 598 ◽  
Author(s):  
Wei-Chih Wen ◽  
Ting-I Chou ◽  
Kea-Tiong Tang
Keyword(s):  
Dynamic Response ◽  
Metal Oxide ◽  
Low Cost ◽  
High Sensitivity ◽  
Temperature Changes ◽  
Concentration Estimation ◽  
Gas Identification ◽  
Different Characteristics ◽  
Metal Oxide Sensor ◽  
Different Gases

Metal-oxide (MOX) gas sensors are widely used for gas concentration estimation and gas identification due to their low cost, high sensitivity, and stability. However, MOX sensors have low selectivity to different gases, which leads to the problem of classification for mixtures and pure gases. In this study, a square wave was applied as the heater waveform to generate a dynamic response on the sensor. The information of the dynamic response, which includes different characteristics for different gases due to temperature changes, enhanced the selectivity of the MOX sensor. Moreover, a polynomial interaction term mixture model with a dynamic response is proposed to predict the concentration of the binary mixtures and pure gases. The proposed method improved the classification accuracy to 100%. Moreover, the relative error of quantification decreased to 1.4% for pure gases and 13.0% for mixtures.

Thermal Drift of Convection-Based Micromachined Accelerometer

2007 ◽  
Author(s):  
Andy Bo Wu ◽  
John Jones
Keyword(s):  
Proof Mass ◽  
Low Cost ◽  
High Sensitivity ◽  
Working Fluid ◽  
Thermal Drift ◽  
Working Fluids ◽  
Temperature Changes ◽  
Heated Fluid ◽  
Sensitivity Changes ◽  
Convective Accelerometer

A novel micromachined accelerometer without proof mass, based on the buoyancy of a heated fluid around a polysilicon heater, has previously been developed and reported. Significant features of this class of accelerometer include low cost and the combination of high sensitivity with high survivability. However, one of its big disadvantages is thermal drift: the sensitivity changes rapidly as the ambient temperature changes. A recent numerical and experimental study has shown that the sensitivity of the convective accelerometer is a function of the Rayleigh number of the working fluid. Using this criterion, a few liquids were selected as potential working fluids to improve the sensitivity of the accelerometer. The CFD program ‘FLOTRAN’ was used to model accelerometer performance using each of these fluids. Based on FLOTRAN modeling, some fluids were selected for experimental investigation. The thermal drift of the accelerometer using different working fluids was documented and the reasons for this thermal drift were discovered. Based on this observation, some possible solutions were proposed to reduce or eliminate the thermal drift.

scholarly journals Continuous methane concentration measurements at the Greenland Ice Sheet-atmosphere interface using a low-cost low-power metal oxide sensor system

2019 ◽  
Author(s):  
Christian Juncher Jørgensen ◽  
Jacob Mønster ◽  
Karsten Fuglsang ◽  
Jesper Riis Christiansen
Keyword(s):  
Metal Oxide ◽  
Low Power ◽  
Low Cost ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Mean Bias Error ◽  
Concentration Difference ◽  
Calibration Period ◽  
Field Calibration ◽  
Metal Oxide Sensor

Abstract. In this paper, the performance of a low-cost and low-power methane (CH4) sensing system prototype based on a metal oxide sensor (MOS) sensitive to CH4 is tested in a natural CH4 emitting environment at the Greenland Ice sheet (GrIS). We investigate if the MOS could be used as a supplementary measurement technique for monitoring CH4 emissions from the GrIS with the scope of setting up a CH4 monitoring network along the GrIS. The performance of the MOS is evaluated on basis of parallel measurements using a CRDS reference instrument for v over a field calibration period of approximately 100 h. Results from the field calibration period show that CH4 concentrations measured with the MOS is in very good agreement with the reference CRDS. The absolute concentration difference between the MOS and the CRDS reference values within the measured concentration range of approximately 2–100 ppm CH4 were generally lower than 5 ppm CH4, while the relative concentration deviations between the MOS and the CRDS were generally below 10 %. Calculated mean bias error for the entire field calibration period was −0.05 ppm with a standard deviation of ± 1.69 ppm (n = 37 140). The results confirms that low-cost and low-power MOS can be effectively used for atmospheric CH4 measurements under stable water vapor conditions. The primary scientific importance of the study is that it provides a clear example on how the application of low cost technology can enhance our future understanding on the climatic feedbacks from the cryosphere to the atmosphere.

scholarly journals An Approximation for Metal-Oxide Sensor Calibration for Air Quality Monitoring Using Multivariable Statistical Analysis

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4781
Author(s):  
Diego Sales-Lérida ◽  
Alfonso J. Bello ◽  
Alberto Sánchez-Alzola ◽  
Pedro Manuel Martínez-Jiménez
Keyword(s):  
Air Quality ◽  
Metal Oxide ◽  
Least Squares Method ◽  
Low Cost ◽  
Quality Monitoring ◽  
Sensor Calibration ◽  
Calibration Data ◽  
Air Quality Monitoring ◽  
Human Beings ◽  
Metal Oxide Sensor

Good air quality is essential for both human beings and the environment in general. The three most harmful air pollutants are nitrogen dioxide (NO2), ozone (O3) and particulate matter. Due to the high cost of monitoring stations, few examples of this type of infrastructure exist, and the use of low-cost sensors could help in air quality monitoring. The cost of metal-oxide sensors (MOS) is usually below EUR 10 and they maintain small dimensions, but their use in air quality monitoring is only valid through an exhaustive calibration process and subsequent precision analysis. We present an on-field calibration technique, based on the least squares method, to fit regression models for low-cost MOS sensors, one that has two main advantages: it can be easily applied by non-expert operators, and it can be used even with only a small amount of calibration data. In addition, the proposed method is adaptive, and the calibration can be refined as more data becomes available. We apply and evaluate the technique with a real dataset from a particular area in the south of Spain (Granada city). The evaluation results show that, despite the simplicity of the technique and the low quantity of data, the accuracy obtained with the low-cost MOS sensors is high enough to be used for air quality monitoring.

scholarly journals Semiconductor Metal Oxide Nanoparticles: A Review for the Potential of H2S Gas Sensor Application

2020 ◽  
pp. 199-208
Author(s):  
Zaid Hameed Mahmoud ◽  
Omar Dhaa Abdalstar ◽  
Noor Sabah
Keyword(s):  
Metal Oxide ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Low Cost ◽  
Metal Oxide Nanoparticles ◽  
High Sensitivity ◽  
Modern World ◽  
H2s Gas Sensor ◽  
Work Mechanism ◽  
Semiconductor Metal Oxide

In modern world, gas sensors play important role in many fields of technology used for air pollution, breath analysis, public safety and many others. Gas sensor based semiconductor metal oxide is mostly used in these applications because of low cost, ease-to-use, high sensitivity and lower power consumption. This paper gives an overview about the semiconductor metal oxide and reviews why using it as sensing of gases in electrical applications and then it addresses to the work mechanism of a sensor to sensing H2S gas.

scholarly journals Continuous methane concentration measurements at the Greenland ice sheet–atmosphere interface using a low-cost, low-power metal oxide sensor system

2020 ◽  
Vol 13 (6) ◽  
pp. 3319-3328
Author(s):  
Christian Juncher Jørgensen ◽  
Jacob Mønster ◽  
Karsten Fuglsang ◽  
Jesper Riis Christiansen
Keyword(s):  
Metal Oxide ◽  
Low Power ◽  
Low Cost ◽  
Relative Concentration ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Concentration Difference ◽  
Calibration Period ◽  
Field Calibration ◽  
Metal Oxide Sensor

Abstract. In this paper, the performance of a low-cost and low-power methane (CH4) sensing system prototype based on a metal oxide sensor (MOS) sensitive to CH4 is tested in a natural CH4-emitting environment at the Greenland ice sheet (GrIS). We investigate if the MOS could be used as a supplementary measurement technique for monitoring CH4 emissions from the GrIS with the scope of setting up a CH4 monitoring network along the GrIS. The performance of the MOS is evaluated on the basis of simultaneous measurements using a cavity ring-down spectroscopy (CRDS) reference instrument for CH4 over a field calibration period of approximately 100 h. Results from the field calibration period show that CH4 concentrations measured with the MOS are in very good agreement with the reference CRDS. The absolute concentration difference between the MOS and the CRDS reference values within the measured concentration range of approximately 2–100 ppm CH4 was generally lower than 5 ppm CH4, while the relative concentration deviations between the MOS and the CRDS were generally below 10 %. The calculated root-mean-square error (RMSE) for the entire field calibration period was 1.69 ppm (n=37 140). The results confirm that low-cost and low-power MOSs can be effectively used for atmospheric CH4 measurements under stable water vapor conditions. The primary scientific importance of the study is that it provides a clear example of how the application of low-cost technology can enhance our future understanding on the climatic feedbacks from the cryosphere to the atmosphere.

Design on the Amplifier Circuit of Metal-Oxide Semiconductor Gas-Sensitive Sensor

2012 ◽  
Vol 220-223 ◽  
pp. 1939-1942 ◽  
Author(s):  
Xi Feng Liang ◽  
Li Hao Liu
Keyword(s):  
Metal Oxide ◽  
Detection System ◽  
Low Cost ◽  
High Sensitivity ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Gas Detection ◽  
Amplifier Circuit ◽  
Detection Systems ◽  
System A

Metal-oxide semiconductor gas-sensitive sensors have various advantages as the basic devices of gas detection systems, such as high sensitivity, fast responsibility and low cost, etc. They are widely applied to many fields. Amplifier circuit is an important section of gas detection system. A new type of amplifier circuit including a three-stage operational amplifier was designed in the paper which can effectively eliminate the influence of the follow-up circuit on the sensor output. Theory analysis and experimental simulations were performed. The results show that the output voltage signals have a linear relation with the concentrations of the detected gas.

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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