Ppm Carbon Monoxide Gas Research Articles

RGO/CuCl-Based Flexible Gas Sensor for High-Concentration Carbon Monoxide Gas Detection at Room Temperature.

Carbon monoxide (CO) gas sensors are widely used, especially for environmental monitoring in confined spaces such as the landscape of mining cave ruins in mining parks, which is essential for ensuring the health and safety of tourists and staff. In this paper, a flexible CO gas sensor based on polyimide, interdigital electrodes, and reduced graphene oxide (RGO)/cuprous chloride (CuCl) composite film is designed and manufactured for reliable room temperature detection of high-concentration CO gas. The structure size of RGO/CuCl gas-sensitive film is 5 × 5 mm. The RGO with a 62.65% C-C bond is prepared by the thermal reduction method. The test results show that the sensor has a high response in the range of 400-2000 ppm CO gas concentration, and the maximum response is 1.56. The linear correlation coefficient of the sensor is 0.981, which indicates that the sensor has good output response characteristics. The response time of the sensor for 400 ppm CO gas is 332 s, which indicates that the sensor has a fast response rate. Furthermore, compared with other gases, the sensor shows higher gas selectivity for CO gas. This sensor has the characteristics of small size and easy attachment; therefore, it can be installed on the shoulder or helmet of tourists' safety suits, providing personalized real-time warning prompts for tourists' physical health status.

Simvastatin attenuates delayed encephalopathy induced by carbon monoxide poisoning in rats by regulating oxidative stress, inflammation and NF-κB pathway

Carbon monoxide (CO) poisoning is a leading cause of morbidity and mortality worldwide. The delayed encephalopathy occurs a period after poisoning in patients without effective treatment. Simvastatin (Sim), a lipid-lowering drug, was reported to exert endothelial protective effects and inhibit inflammatory response. This research focused on the effects of Sim on delayed encephalopathy caused by CO poisoning. The acute CO poisoning model was established by exposing rats to 2500 ppm CO gas for 40 min, then 3000 ppm for 30 min or until they lost consciousness. Rats in the treatment group were given Sim (20 mg/kg/day, ig.). The behavioral tests included the Morris water maze test and shuttle box. The pathological changes were evaluated by H and E staining. The inflammatory mediators were analyzed by ELISA. The expression levels of eNOS, iNOS and the NF-κB-related proteins were analyzed by Western blot. The results showed that Sim could alleviate CO-induced behavioral disorders and the hippocampal nerve cells apoptosis. Sim administration reversed the effects of CO on oxidative stress-related molecules. Sim could also inhibit the production of the inflammatory mediators induced by CO. The level of eNOS was decreased after CO exposure, while iNOS was increased. Sim could significantly inhibit the effects of CO. Furthermore, Sim inhibited the phosphorylation of IκBα (an NF-κB inhibitory protein), i.e., the activation of NF-κB, which indicated that Simvastatin reduced the inflammatory response induced by CO poisoning partially through inhibiting the activation of NF-κB signaling pathway. To sum up, our research indicated that Sim could attenuate the delayed encephalopathy induced by CO poisoning via regulating oxidative stress, inflammation and NF-κB pathway.

Cu/CuO@ZnO Hollow Nanofiber Gas Sensor: Effect of Hollow Nanofiber Structure and P-N Junction on Operating Temperature and Sensitivity.

For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the presence of 100 ppm CO gas, the Cu/CuO-photodeposited ZnO hollow nanofiber (Cu/CuO@ZnO HNF) showed twice higher sensitivity than that of pure ZnO nanofiber at a relatively low working temperature of 300 °C. The hollow structure and p–n junction between Cu/CuO and ZnO would be considered to contribute to the enhancement of sensitivity to CO gas at 300 °C due to the improved specific surface area and efficient electron transfer.

Preparation of (002)-oriented ZnO for CO gas sensor

In this work, (002) oriented ZnO thin film for carbon monoxide (CO) gas sensing application has been synthesized on the glass substrate using diethanolamine (DEA) as a chelating agent by two-step process. First, the seed layers were formed at a glass substrate using dip coating method, and second, ZnO nanostructure was grown using Chemical Bath Deposition (CBD) at low temperature. The structural and orientation of ZnO films were confirmed using x-ray Diffraction (XRD) while their morphologies and size were analyzed using Scanning Electron Microscopy (SEM). Diffraction pattern showed that the resulting film has wurtzite structure and an extremely sharp (002) peak was found, indicated that the ZnO nanostructure was growth along (002) orientation. The SEM image showed that the (002) oriented ZnO has hexagonal shape nanorods which vertically aligned. It was found that the diameter and length of ZnO nanorods were 71–96 nm and 666 nm, respectively. The gas sensing performance was investigated at various temperatures (160 °C, 200 °C, 250 °C, and 300 °C) and CO gas concentrations (10, 30, 50, 70 and 90 ppm). The results showed that the highest response, 53.25% was obtained at 200 °C toward 90 ppm CO gas. The response and CO gas concentration have a good linearity relationship which indicated that the (002) oriented ZnO has high potential for high sensitive CO gas sensor.

Perancangan Sistem Sensor Pemonitor Lingkungan Berbasis Jaringan Sensor Nirkabel

Air pollution is a problem that get a lot of people’s attention, especially at campus environment. It is evocate the stakeholder of campus to monitor the environmental conditions at the campus which themed a green campus. Advances in science and technology, especially in computer and embedded systems in principle can be applied to solve this problem. There are creating an application system that is equipped with sensor to monitor the air quality level wirelessly. The system supports several environmental monitoring sensors that are connected in a wireless sensor network. The objective of this research was to design and create a sensor system that can monitor environment condition quantity by providing the appropriate output value. Sensors that used to read the air quality parameters is TGS 2600 to read the gas concentration of carbon monoxide (CO), TGS 2201 for nitrogen dioxide (NO2), GP2Y1010AU0F for particulate matter, BH1750 for light ambient, and SHT11 for humidity and temperature. This sensor system using Arduino board that based on Atmega 2560 microcontroller. This system is equipped with RTC as a time and GPS as a coordinate where the sensor system is placed as a node. The result of this reseach is the system able to read parameters as air quality monitoring well. The error reading in this sensor system is 0.69 ppm CO gas, 2.8 lx on the intensity of light, 0.22 C in temperature reading, and 0.98% in humidity readings.

Theoretical and Spectroscopic Studies of N-([4-aminophenyl]ethynyltoluene)-N’-(1-naphthanoyl thiourea (ATT) as Carbon Monoxide Gas Chemosensor

Acetylide and thiourea moieties individually provides a wide range of electronic properties as they possess electronic delocalization in extended rigid π orbital system in their designated structures. In this work, a new derivative of N-([4–aminophenyl] ethynyltoluene)-N’-(1-naphthanoyl) thiourea (ATT) was successfully synthesized and spectroscopically characterized by using FT-IR, NMR, and UV-Vis analysis. In turn, the development of new sensing material thin-film based on ATT has been accomplished by incorporating with polyvinyl chloride (PVC) via dip-coating technique. The difference in absorption behavior using UV-visible spectroscopic analysis was employed to determine the sensitivity of thin-film towards carbon monoxide (CO) gas of 10, 20, and 30 ppm. ATT exhibits high sensitivity towards 30 ppm CO gas with 55% sensitivity. Quantum mechanical calculation via Gaussian 09 shows that ATT has potential van der Waals interaction towards CO with stabilization energy-6.54 kJ/mol and 3.14Ǻ of interaction distance between substrate and analyte. It is proven that ATT as single molecule gives great potential to be explored and used as sensing material application particularly in CO detection.

High Performance CO Sensors Utilizing Sprayed Distributed Toluene-Based Gold Nanoparticles

This study presents a simple and low-cost spray coating process for producing high performance CO (carbon monoxide) sensors utilizing toluene-based gold nanoparticles (Au-NPs). Thanks to the success synthesis of Au-NPs in toluene, this low surface tension organic solvent prevents Au-NPs from colligation. And therefore Au-NPs can be well dispersed on the surface of the electrodes as the sensing layer during spraying. To compare with the typical metal oxide based CO sensors that have to work at a higher working temperature of about 150~350°C, the produced sensor can work at room temperature and have a better detection limit for CO gas (5 ppm). Experimental results indicate good linear sensitivity under repeated measurements for concentration range from 5 250 ppm (R2=0.996). The repeatability is also confirmed by measuring 100 ppm CO gas, the calculated variation is less than 2.8% for six repeating measurements. The process developed in this study can be used to produce not only high performance CO gas sensors but other related gas sensors.

The Diagnostic Value of Serum Ischemia-modified Albumin Levels in Experimentally Induced Carbon Monoxide Poisoning and Their Correlation With Poisoning Severity

The objectives were to determine the diagnostic value of blood ischemia-modified albumin (IMA) levels in experimentally induced carbon monoxide (CO) poisoning and to analyze their correlation with poisoning severity. Thirty-six female rats were randomly assigned to one of three groups: I (control group), II (low-dose CO poisoning group), and III (high-dose CO poisoning group). The control group was kept in room air, while groups II and III were exposed to 3 L/min of 3,000 ppm and 3 L/min of 5,000 ppm CO gas for 30 minutes, respectively. Serum carboxyhemoglobin (COHb), IMA, and malondialdehyde (MDA) levels; brain, heart, lung, liver, and kidney tissue MDA measurements; and histopathologic damage scores were then compared. IMA levels were significantly higher in groups II and III than in group I. A moderate positive correlation was observed between COHb and IMA levels. There was a strong positive correlation between COHb levels and degree of damage in all organs, but IMA and MDA levels did not reflect a similar correlation. Ischemia-modified albumin levels are higher in rats exposed to CO. This indicates that IMA levels can potentially be important in the diagnosis of exposure to CO or of CO poisoning. However, IMA levels are not a good biochemical marker in terms of determining the severity of poisoning.

Controlled Synthesis of Hollow Cu2‐xTe Nanocrystals Based on the Kirkendall Effect and Their Enhanced CO Gas‐Sensing Properties

This paper develops a facile solution-based method to synthesize hollow Cu2-x Te nanocrystals (NCs) with tunable interior volume based on the Kirkendall effect. Transmission electron microscopy images and time-dependent absorption spectra reveal the temporal growth process from solid copper nanoparticles to hollow Cu2-x Te NCs. Furthermore, the as-prepared hollow Cu2-x Te NCs show enhanced sensitivity for the detection of carbon monoxide (CO), which is often referred to as the "silent killer". The response and recovery time of the as-prepared sensor for the detection of 100 ppm CO gas are estimated to be about 21 and 100 s, respectively, which are sufficient to render it a promising candidate for effective CO gas-sensing applications. Such enhanced performance is achieved owing to the small grain size and large specific area of the hollow nanostructures. Therefore, the obtained hollow NCs based on the Kirkendall effect may have the potential as new functional blocks for high-performance gas sensors.

A Tracer Analysis Study on the Redistribution and Oxidization of Endogenous Carbon Monoxide in the Human Body

Past studies have suggested that some carbon monoxide (CO) moves from blood haemoglobin to tissue cells and that mitochondrial cytochrome c oxidase oxidizes CO to carbon dioxide (CO2). However, no study has demonstrated this redistribution and oxidization of CO under physiological conditions. The objective of this study was to trace the redistribution and oxidization of CO in the human body by detecting 13CO2 production after the inhalation of 13CO. In Experiment 1, we asked a healthy subject to inhale 50 ppm 13CO gas. In Experiment 2, we circulated heparinized human blood in a cardio-pulmonary bypass circuit and supplied 50 ppm 13CO gas to the oxygenator. We sequentially sampled exhaled and output gases and measured the 13CO2/12CO2 ratios. In Experiment 1, the exhaled 13CO2/12CO2 ratio increased significantly between 4 to 31 h of 13CO inhalation. In Experiment 2, the output 13CO2/12CO2 ratio showed no significant increase within 36 h of 13CO input. Experiment 1 demonstrated the oxidization of CO in the human body under physiological conditions. Experiment 2 confirmed that oxidization does not occur in the circulating blood and indicated the redistribution of CO from blood carboxyhaemoglobin to tissue cells.

05/00724 Epi-n-IZO thin films/〈1 0 0〉 Si, GaAs and InP by L-MBE — a novel feasibility study for SIS type solar cells

In this paper we report the potential of ITO/n-GaAs Schottky diode sensor for carbon monoxide detection at room temperature. The ITO/n-GaAs Schottky contacts were developed using an evaporation system in our laboratory. Due to the very low operating temperature of the diode which shows rapid response to carbon monoxide (CO) it can be applied to micro-sized devices for IC technology. It has been found that the diode exhibited a saturation current of 1×10−10 A at room temperature in the absence of CO gas, whereas a value of 1.1×10−9 A was obtained for saturation current at room temperature in the presence of 1000 ppm CO gas. This excellent responsivity of ITO/n-GaAs diode sensor at room temperature can be due to penetration of CO molecules into the thin ITO layer (150 nm) and changing its work function to a lower value to form a lower Schottky barrier. A comparative study showed that Schottky gas sensor fabricated with gold metal contact presented different sensitivities to CO gas. The relation between different Schottky contacts subjected to carbon monoxide is discussed.

Room temperature carbon monoxide sensor using ITO/ n-GaAs Schottky contact

In this paper we report the potential of ITO/ n-GaAs Schottky diode sensor for carbon monoxide detection at room temperature. The ITO/ n-GaAs Schottky contacts were developed using an evaporation system in our laboratory. Due to the very low operating temperature of the diode which shows rapid response to carbon monoxide (CO) it can be applied to micro-sized devices for IC technology. It has been found that the diode exhibited a saturation current of 1×10 −10 A at room temperature in the absence of CO gas, whereas a value of 1.1×10 −9 A was obtained for saturation current at room temperature in the presence of 1000 ppm CO gas. This excellent responsivity of ITO/ n-GaAs diode sensor at room temperature can be due to penetration of CO molecules into the thin ITO layer (150 nm) and changing its work function to a lower value to form a lower Schottky barrier. A comparative study showed that Schottky gas sensor fabricated with gold metal contact presented different sensitivities to CO gas. The relation between different Schottky contacts subjected to carbon monoxide is discussed.