scholarly journals Precision and Limits of Detection for Selected Commercially Available, Low-Cost Carbon Dioxide and Methane Gas Sensors

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3157 ◽  
Author(s):  
Wesley T. Honeycutt ◽  
M. Tyler Ley ◽  
Nicholas F. Materer
Keyword(s):  
Carbon Dioxide ◽  
Low Cost ◽  
Detection Limits ◽  
Detection Range ◽  
Methane Gas ◽  
Accuracy And Precision ◽  
Sensor Platform ◽  
Industrial Monitoring ◽  
And Performance ◽  
The Individual

The performance of a sensor platform for environmental or industrial monitoring is sensitive to the cost and performance of the individual sensor elements. Thus, the detection limits, accuracy, and precision of commercially available, low-cost carbon dioxide and methane gas concentration sensors were evaluated by precise measurements at known gas concentrations. Sensors were selected based on market availability, cost, power consumption, detection range, and accuracy. A specially constructed gas mixing chamber, coupled to a precision bench-top analyzer, was used to characterize each sensor during a controlled exposure to known gas concentrations. For environmental monitoring, the selected carbon dioxide sensors were characterized around 400 ppm. For methane, the sensor response was first monitored at 0 ppm, close to the typical environmental background. The selected sensors were then evaluated at gas concentrations of several thousand ppm. The determined detection limits accuracy, and precision provides a set of matrices that can be used to evaluate and select sensors for integration into a sensor platform for specific applications.

scholarly journals Evaluation and enhancement of a low-cost NDIR CO<sub>2</sub> sensor

2017 ◽  
Author(s):  
Cory R. Martin ◽  
Ning Zeng ◽  
Anna Karion ◽  
Russell R. Dickerson ◽  
Xinrong Ren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Standard Deviation ◽  
Low Cost ◽  
Linear Regression Analysis ◽  
Ambient Air ◽  
Multivariate Linear Regression Analysis ◽  
Laser Absorption ◽  
Accuracy And Precision ◽  
Carbon Dioxide Concentrations ◽  
Ambient Air Monitoring

Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square (RMS) error between ~ 5 to 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had for one minute data a standard deviation of between 1.6 ppm and 4.4 ppm. The median standard deviation improved from 8.08 for off the shelf sensors to 1.89 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

Assessment on the Synthesis and Performance of Low-Cost Chitosan-Coated Natural Zeolite Adsorbent for Post-Combustion Carbon Dioxide Capture

2018 ◽  
Vol 775 ◽  
pp. 383-389
Author(s):  
Dominique Jan Bacalso Tan ◽  
Bryan B. Pajarito
Keyword(s):  
Carbon Dioxide ◽  
Natural Zeolite ◽  
Carbon Dioxide Capture ◽  
Low Cost ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Zeolite Adsorbent ◽  
And Performance ◽  
Adsorption Desorption ◽  
Good Retention

An adsorbent for post-combustion carbon dioxide capture was prepared using low-cost and sustainable natural zeolite coated with chitosan. An optimum adsorbent was identified from 3 levels of particle size of natural zeolite and 10 levels of chitosan loading. The optimum adsorbent was characterized using infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis and differential scanning calorimetry. The chemical and thermal properties of the adsorbent indicated successful coating of chitosan on natural zeolite. The adsorbent registered competitive dynamic adsorption capacity of 0.81 mmol g-1 with good retention, at least, up to 5 adsorption-desorption cycles.

scholarly journals Characterization Techniques as Supporting Tools for the Interpretation of Biochar Adsorption Efficiency in Water Treatment: A Critical Review

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5063
Author(s):  
Michele Castiglioni ◽  
Luca Rivoira ◽  
Irene Ingrando ◽  
Massimo Del Bubba ◽  
Maria Concetta Bruzzoniti
Keyword(s):  
Water Treatment ◽  
Water Purification ◽  
Low Cost ◽  
Efficiency Index ◽  
Adsorption Efficiency ◽  
The Past ◽  
Physicochemical Features ◽  
And Performance ◽  
The Individual ◽  
Significant Attention

Over the past decade, biochar (BC) has received significant attention in many environmental applications, including water purification, since it is available as a low-cost by-product of the energetic valorisation of biomass. Biochar has many intrinsic characteristics, including its porous structure, which is similar to that of activated carbon (AC), which is the most widely used sorbent in water treatment. The physicochemical and performance characteristics of BCs are usually non-homogenously investigated, with several studies only evaluating limited parameters, depending on the individual perspective of the author. Within this review, we have taken an innovative approach to critically survey the methodologies that are generally used to characterize BCs and ACs to propose a comprehensive and ready-to-use database of protocols. Discussion about the parameters of chars that are usually correlated with adsorption performance in water purification is proposed, and we will also consider the physicochemical properties of pollutants (i.e., Kow). Uniquely, an adsorption efficiency index BC/AC is presented and discussed, which is accompanied by an economic perspective. According to our survey, non-homogeneous characterization approaches limit the understanding of the correlations between the pollutants to be removed and the physicochemical features of BCs. Moreover, the investigations of BC as an adsorption medium necessitate dedicated parallel studies to compare BC characteristics and performances with those of ACs.

scholarly journals A Low-Cost, Accurate, and High-Precision Fluid Dispensing System for Microscale Application

2016 ◽  
Vol 22 (2) ◽  
pp. 144-152 ◽  
Author(s):  
Champak Das ◽  
Guochun Wang ◽  
Chien Nguyen
Keyword(s):  
Low Cost ◽  
Flow Characteristics ◽  
Positive Displacement ◽  
Real Time Measurement ◽  
Fluid Dispensing ◽  
Accuracy And Precision ◽  
Displacement Pump ◽  
The Individual ◽  
Similar Accuracy ◽  
The Cost

We present here the development of a low-cost, accurate, and precise fluid dispensing system. It can be used with peristaltic or any other pump to improve the flow characteristics. The dispensing system has a range of 1 to 100 µL with accuracy of ~99.5% and standard deviation at ~150 nL over the entire range. The system developed does not depend on the accuracy or precision of the driving pump; therefore, any positive displacement pump can be used to get similar accuracy and precision, which gives an opportunity to reduce the cost of the system. The dispensing system does not require periodic calibration and can also be miniaturized for microfluidic application. Although primarily designed for aqueous liquid, it can be extended for different nonconductive liquids as well with modifications. The unit is further used for near real-time measurement of lactate from microdialysate. The individual components can easily be made disposable or sterilized for use in biomedical applications.

scholarly journals IMPROVEMENT AND PERFORMANCE EVALUATION OF A SYSTEM FOR MONITORING ROTATIONS AND DISPLACEMENTS OF BRIDGES BASED ON LASER POINTER AND DIGITAL PHOTOGRAMMETRY

2019 ◽  
Vol XLII-2/W18 ◽  
pp. 1-5
Author(s):  
G. Artese
Keyword(s):  
Low Cost ◽  
Previous Method ◽  
Digital Photogrammetry ◽  
Laser Pointer ◽  
Generic Point ◽  
Elastic Line ◽  
High Brightness ◽  
Transverse Rotation ◽  
And Performance ◽  
The Individual

Abstract. A system for monitoring rotations and displacements of bridges based on laser pointer and digital photogrammetry is described. The system uses three common laser pointers and image processing. The inclination of the elastic line is measured by analysing the individual frames of an HD video of the laser beam footprint projected onto a flat target. The methodology, able to conjugate a high precision, low cost, and easiness of use, is an evolution of a method developed at University of Calabria, Italy. The use of three laser pointers allows to improve the performance of the previous method, obtaining both displacements and rotations at a generic point of the bridge deck, and deriving the transverse rotation of the deck cross section. The investigated method exploits the laser pointers’ property to provide a steady pointing direction, a long-range and a high-brightness visible imprint. The method and the results of an experimental test are described and discussed.

scholarly journals Correlation of Respiratory Aerosols and Metabolic Carbon Dioxide

2021 ◽  
Vol 13 (21) ◽  
pp. 12203
Author(s):  
Niklas Kappelt ◽  
Hugo Savill Russell ◽  
Szymon Kwiatkowski ◽  
Alireza Afshari ◽  
Matthew Stanley Johnson
Keyword(s):  
Carbon Dioxide ◽  
Oral Fluid ◽  
Low Cost ◽  
Co2 Concentration ◽  
Transmission Route ◽  
Viral Loads ◽  
Co2 Concentrations ◽  
Carbon Dioxide Co2 ◽  
The Individual ◽  
Metabolic Carbon

Respiratory aerosols from breathing and talking are an important transmission route for viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Previous studies have found that particles with diameters ranging from 10 nm to 145 μm are produced from different regions in the respiratory system and especially smaller particles can remain airborne for long periods while carrying viral RNA. We present the first study in which respiratory aerosols have been simultaneously measured with carbon dioxide (CO2) to establish the correlation between the two concentrations. CO2 concentrations are easily available through low-cost sensors and could be used to estimate viral exposure through this correlation, whereas source-specific aerosol measurements are complicated and not possible with low-cost sensors. The increase in both respiratory aerosols and CO2 was linear over ten minutes in a 2 m3 chamber for all participants, suggesting a strong correlation. On average, talking released more particles than breathing, with 14,600 ± 16,800 min−1 (one-σ standard deviation) and 6210 ± 5630 min−1 on average, respectively, while CO2 increased with 139 ± 33 ppm min−1 during talking and 143 ± 29 ppm min−1 during breathing. Assuming a typical viral load of 7×106 RNA copies per mL of oral fluid, ten minutes of talking and breathing are estimated to produce 1 and 16 suspended RNA copies, respectively, correlating to a CO2 concentration of around 1800 ppm in a 2 m3 chamber. However, viral loads can vary by several orders of magnitude depending on the stage of the disease and the individual. It was therefore concluded that, by measuring CO2 concentrations, only the number and volume concentrations of released particles can be estimated with reasonable certainty, while the number of suspended RNA copies cannot.

scholarly journals Evaluation and environmental correction of ambient CO<sub>2</sub> measurements from a low-cost NDIR sensor

2017 ◽  
Vol 10 (7) ◽  
pp. 2383-2395 ◽  
Author(s):  
Cory R. Martin ◽  
Ning Zeng ◽  
Anna Karion ◽  
Russell R. Dickerson ◽  
Xinrong Ren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Low Cost ◽  
Linear Regression Analysis ◽  
Ambient Air ◽  
Multivariate Linear Regression Analysis ◽  
Laser Absorption ◽  
Accuracy And Precision ◽  
Carbon Dioxide Concentrations ◽  
Ambient Air Monitoring ◽  
Research Grade

Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square error (RMSE) between  ∼ 5 and 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had an RMSE of between 1.7 and 4.3 ppm for 1 min data. The median RMSE improved from 9.6 for off-the-shelf sensors to 1.9 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

scholarly journals Application of Graphene-Based Materials for Detection of Nitrate and Nitrite in Water—A Review

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 54 ◽  
Author(s):  
Daoliang Li ◽  
Tan Wang ◽  
Zhen Li ◽  
Xianbao Xu ◽  
Cong Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensors ◽  
Low Cost ◽  
Cost Effective ◽  
Future Research ◽  
Detection Range ◽  
Long Term Stability ◽  
And Performance ◽  
Limit Sensitivity ◽  
Nitrate And Nitrite

Nitrite and nitrate are widely found in various water environments but the potential toxicity of nitrite and nitrate poses a great threat to human health. Recently, many methods have been developed to detect nitrate and nitrite in water. One of them is to use graphene-based materials. Graphene is a two-dimensional carbon nano-material with sp2 hybrid orbital, which has a large surface area and excellent conductivity and electron transfer ability. It is widely used for modifying electrodes for electrochemical sensors. Graphene based electrochemical sensors have the advantages of being low cost, effective and efficient for nitrite and nitrate detection. This paper reviews the application of graphene-based nanomaterials for electrochemical detection of nitrate and nitrite in water. The properties and advantages of the electrodes were modified by graphene, graphene oxide and reduced graphene oxide nanocomposite in the development of nitrite sensors are discussed in detail. Based on the review, the paper summarizes the working conditions and performance of different sensors, including working potential, pH, detection range, detection limit, sensitivity, reproducibility, repeatability and long-term stability. Furthermore, the challenges and suggestions for future research on the application of graphene-based nanocomposite electrochemical sensors for nitrite detection are also highlighted.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Sign in / Sign up

Export Citation Format

Share Document