scholarly journals Analysis and Detection of a Target Gas System Based on TDLAS & LabVIEW

2019 ◽  
Vol 9 (3) ◽  
pp. 4196-4199 ◽  
Author(s):  
F. Alorifi ◽  
S. M. A. Ghaly ◽  
M. Y. Shalaby ◽  
M. A. Ali ◽  
M. O. Khan
Keyword(s):  
Absorption Spectrum ◽  
Second Harmonic ◽  
Detection System ◽  
Infrared Absorption Spectrum ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Gas Detection ◽  
Measured Signal ◽  
Gas Concentration ◽  
Detection Techniques

This paper introduces detection techniques of target gas concentration based on infrared absorption spectrum method and the simulation of the gas detection system using LabVIEW. In this work, the harmonic detection is performed by wavelength modulation technique with a related frequency signal to cover the measured signal and get the gas absorption coefficient that can be analysed to give a gas concentration. A series of simulations are carried out to scan weak absorption lines and extract the second harmonic curve of the absorption spectrum of the target gas. The absorption and second harmonic curves are acquired by changing the parameters of the target gas concentration and line width. This work claims to be a contribution to the study and the comprehension of gas detection system based on tunable diode laser absorption spectroscopy and can serve as a basis for practical data acquisition.

A Fire Warning Method Using Tunable Diode Laser Absorption Spectroscopy

2021 ◽  
Vol 16 (2) ◽  
pp. 222-229
Author(s):  
Lin Feng ◽  
Jian Wang ◽  
Chao Ding
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Gas Concentration ◽  
Laser Absorption ◽  
Output Wavelength ◽  
Light Beams ◽  
Diode Laser Absorption

Tunable diode laser absorption spectroscopy (TDLAS) technology is adopted herein to detect fire gas produced in the early stage of the fire. Based on this technology, a fire warning detection system with multiple lasers and detectors is proposed. Multiple drivers input laser’s temperature and injected current data, making its output wavelength consistent with the measured gas’ absorption peak wavelengths in absorption spectroscopy. Multiple light beams are coupled to the same optical fiber. After the light beams pass through the long optical path absorption cell filled with fire gas, the beams are separated by a converter. The signals are demodulated by different detectors and further analyzed for fire warnings. After the fire warning system’s design, the system’s various hardware modules are designed, including the light source module, TDLAS controller, gas chamber module, photoelectric detector, and data collection. When the temperature remains unchanged, the output wavelength is linearly related to the injected current. When the injected current remains unchanged, the output wavelength is linearly related to the operating temperature. With a semiconductor laser’s injected current of 40 mA, the initial temperature of 38.6 °C, and the output wavelength of 1578.16 nm, the output wavelength increases continuously as the temperature increases. The harmonic signal amplitude after gas absorption is positively correlated with the measured gas concentration, indicating that the second harmonic signals can estimate the fire gas concentration.

scholarly journals The driver design for N2O gas detection system based on tunable interband cascade laser

2019 ◽  
Vol 78 ◽  
pp. 03002
Author(s):  
Lihuan Liao ◽  
Jingjing Zhang ◽  
Daming Dong
Keyword(s):  
Power Supply ◽  
High Efficiency ◽  
Detection System ◽  
Tunable Diode Laser ◽  
Circuit Board ◽  
Gas Detection ◽  
Electrolytic Capacitor ◽  
Negative Power ◽  
Interband Cascade Laser ◽  
Driver Circuit

In this paper, the driver circuit for N2O gas detection system based on tunable interband cascade laser (ICL) is developed. Considering the influence of power supply stability on the digital-analog hybrid drive circuit of tunable diode laser absorption spectroscopy (TDALS), the high-efficiency TPS5430 is used to design the positive and negative power supply circuit. The large electrolytic capacitor + post-stage LC filter combination filter is used to effectively filter out high and low frequency ripple and switching noise. The use of thick high current trace + via + multilayer printed circuit board (PCB) design makes the line temperature rise smaller, more stable and durable, and uses high frequency shielding inductance to effectively reduce radiation interference to ensure the stability of the drive. The STM32F407, a highperformance microcontroller based on the ARM Cortex-M4 core, is used as the master control chip and generates a sawtooth scanning signal. The direct digital synthesizer (DDS) chip ICL8038 is used to generate a sinusoidal modulated signal of a specific frequency. The two signals are superimposed by a reverse addition circuit, and the laser drive signal is generated by a developed positive feedback balanced voltagecurrent conversion circuit. Experimental results show that the driver circuit can well meet the drive development requirements of N2O gas detection systems based on tunable interband cascade laser.

Optimization of Harmonic Detection System for Tunable Diode Laser Absorption Spectroscopy Based on Mathematical Algorithm

2018 ◽  
Vol 13 (10) ◽  
pp. 1533-1542 ◽  
Author(s):  
Danni Shen ◽  
Anji Yu
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Detection System ◽  
Rapid Development ◽  
Noise Removal ◽  
Tunable Diode Laser ◽  
Gas Detection ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Diode Laser Absorption

Traditional gas detection technology has a certain degree of defects in all aspects, and it has not been able to adapt to the rapid development trend. Tunable diode laser absorption spectroscopy (TDLAS) technology has some good performance and is gradually being used in various industries. First, a gas detection instrument is designed. Then, based on subsequent data processing techniques, a wavelet transform algorithm is proposed, and the noise removal and baseline correction functions of the detection system are implemented. The results show that the proposed method has good removal effect on the inherent noise of the system and high efficiency. During the selection of the absorption line, the selected line of some gases cannot avoid the interference of adjacent peaks. Therefore, a mathematical analysis method of differential fold back algorithm is proposed. The absorption peak shape is squeezed by the method of adjacent phase subtraction and displacement superposition. The problem is solved well, and the accuracy of concentration measurement of some gases is effectively improved.

Fiber Optic Temperature and Gas Concentration Sensor for Mine Goaf Area Inner Detecting

2012 ◽  
Vol 524-527 ◽  
pp. 302-305
Author(s):  
Yu Bin Wei ◽  
Xu You Wang ◽  
Min Xin ◽  
Tong Yu Liu ◽  
Chang Wang
Keyword(s):  
Spontaneous Combustion ◽  
Detection System ◽  
Fire Detection ◽  
Tunable Diode Laser ◽  
Gas Concentration ◽  
Beam Tube ◽  
Sensing Technology ◽  
Detection Technology ◽  
Primary Means ◽  
On Line

Spontaneous combustion in coal goaf area is one of major disasters in coal mines. Detection technology based on signature Gas and Temperature is the primary means of spontaneous combustion forecasting of coal goaf area. A real-time remote fire detection system is proposed based on tunable diode laser absorption spectroscopy technology and FBG temperature sensing technology, to achieve valid detect of gas concentration and temperature. The System include fiber mathen concentration sensor and fiber temperature sensor based FBG. The system achieved remote on-line monitoring of gas concentration and temperature in mine goaf, meet the fire forecast need for Coal goaf area. There are obvious advantages Compared with the existing beam tube monitoring system in coal mine.

Measurement and Analysis of near Infrared Spectrum of Gasoline Vapor

2012 ◽  
Vol 571 ◽  
pp. 243-247
Author(s):  
Li Ping Yan ◽  
Shu Li ◽  
Lai Gen Luo ◽  
Min Zhang ◽  
Jing Xin Dong
Keyword(s):  
Absorption Spectrum ◽  
Infrared Spectrum ◽  
Infrared Absorption ◽  
Near Infrared ◽  
Detection System ◽  
Infrared Absorption Spectrum ◽  
Vapor Concentration ◽  
Absorption Characteristic ◽  
Gasoline Vapor ◽  
Near Infrared Spectrum

In the fiber-sensing gas detection system, characteristic of near infrared absorption spectrum of the detected gas is greatly significant. The volatilized gasoline vapor is a mixture rich in various components, of which near infrared absorption spectrum shall be determined by means of experimental measurement. In this paper, an experimental platform is constructed by analyzing absorption characteristic of liquid composition in gasoline within the range of near infrared spectrum, which achieves measurement of the volatilized gasoline vapor with different concentration. In addition, reliability of this measurement method is inspected, a comparison between features of absorption spectrograms of liquid and gas is made, and linear relation of absorbance and concentration of gasoline vapor is verified. The result shows that the experimental data is acceptable and may be used as the basis of further analysis and for design of the online detecting system of gasoline vapor concentration in the hazardous environment.

Intelligent Protection System Against Vehicles’ Carbon Monoxide Gas Leakage by Using Arduino and Global System for Mobile Model

2020 ◽  
Vol 17 (4) ◽  
pp. 1715-1719
Author(s):  
Muna Rashid Al Eissaei ◽  
Feras N. Hasoon ◽  
Suresh Manic
Keyword(s):  
Carbon Monoxide ◽  
Gas Sensor ◽  
Detection System ◽  
Gas Detection ◽  
Significant Problem ◽  
Leakage Detection ◽  
Global System ◽  
Gas Concentration ◽  
Safety Standards ◽  
Gas Leakage

Gas leakage is a significant problem in industries, residential premises and gas powered vehicles. Carbon Monoxide is one type of harmful gas that generates out from vehicle’s AC when it is in ON mode, which can cause suffocation or death for all the passengers within less than hour that according to the science researchers. One of the proposed methods to upgrade safety standards and prevent accidents related to gas leakage is to install gas leakage detection inside the vehicles. This paper discusses the design of gas detection system to detect the presence of a dangerous Carbon Monoxide (Co) leak inside the cars using the MQ-7 gas sensor, and an alert is provided to two users by sending SMS to the programmed mobile numbers. Also, this system decreases the gas concentration by opening the car window using a relay board and motor. If the Co (MQ-7) sensor senses any gas leakage from the AC output of this sensor goes low, and the Arduino monitors this low signal, and it will identify the gas leakage.

scholarly journals A Trace C2H2 Sensor Based on an Absorption Spectrum Technique Using a Mid-Infrared Interband Cascade Laser

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 530 ◽  
Author(s):  
Ye Mu ◽  
Tianli Hu ◽  
He Gong ◽  
Ruiwen Ni ◽  
Shijun Li
Keyword(s):  
Absorption Spectroscopy ◽  
Second Harmonic ◽  
Harmonic Signal ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Integration Time ◽  
Detection Accuracy ◽  
Laser Absorption ◽  
Interband Cascade Laser ◽  
Diode Laser Absorption

In this study, tunable diode laser absorption spectroscopy (TDLAS) combined with wavelength modulation spectroscopy (WMS) was used to develop a trace C2H2 sensor based on the principle of gas absorption spectroscopy. The core of this sensor is an interband cascade laser that releases wavelength locks to the best absorption line of C2H2 at 3305 cm−1 (3026 nm) using a driving current and a working temperature control. As the detected result was influenced by 1/f noise caused by the laser or external environmental factors, the TDLAS-WMS technology was used to suppress the 1/f noise effectively, to obtain a better minimum detection limit (MDL) performance. The experimental results using C2H2 gas with five different concentrations show a good linear relationship between the peak value of the second harmonic signal and the gas concentration, with a linearity of 0.9987 and detection accuracy of 0.4%. In total, 1 ppmv of C2H2 gas sample was used for a 2 h observation experiment. The data show that the MDL is low as 1 ppbv at an integration time of 63 s. In addition, the sensor can be realized by changing the wavelength of the laser to detect a variety of gases, which shows the flexibility and practicability of the proposed sensor.

scholarly journals 245 GHz SiGe sensor system for gas spectroscopy

2015 ◽  
Vol 7 (3-4) ◽  
pp. 271-278 ◽  
Author(s):  
Klaus Schmalz ◽  
Ruoyu Wang ◽  
Wojciech Debski ◽  
Heiko Gulan ◽  
Johannes Borngräber ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Second Harmonic ◽  
Local Oscillator ◽  
Low Noise ◽  
Gas Absorption ◽  
Sensor System ◽  
Phase Locked Loops ◽  
Reference Frequency ◽  
Constant Frequency ◽  
Noise Amplifier

A 245 GHz sensor system for gas spectroscopy is presented, which includes a SiGe receiver (RX), a SiGe transmitter (TX), and a 0.6 m long gas absorption cell between the TX and RX. The integrated local oscillators of the RX and the TX are controlled by two external phase locked loops (PLLs), whose reference frequencies are swept with constant frequency offset for a low IF of the RX. The RX consists of a differential low noise amplifier (LNA), an integrated 122 GHz local oscillator (LO) with 1/64 divider, a 90° differential hybrid, and active subharmonic mixer. The TX consists of an integrated 122 GHz LO with 1/64 divider, and a frequency doubler. The RX and TX are fabricated in 0.13 µm SiGe BiCMOS with ft/fmax of 300/500 GHz. Using external dielectric lenses for the TX and RX, the absorption spectrum of gaseous methanol has been measured. The reference frequency of the TX-PLL is modulated for frequency-modulation spectroscopy. The performance of the sensor system is demonstrated by measuring the 2f absorption spectrum (second harmonic detection) of gaseous methanol.

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