Infrared Carbon Dioxide Research Articles

Research on the Detection Method of Martian Atmospheric Temperature and Pressure Profile Based on Laser Occultation Technology

As an important target of space exploration, Mars has attracted a lot of attention due to its unique geographical and atmospheric conditions. The detection of the vertical profiles of Mars atmospheric parameters provides deeper insights into the structure and composition of the Martian atmosphere. Meanwhile, it holds significant importance for the design and execution of Mars exploration missions. This paper presents a detection method for the Martian atmosphere utilizing laser occultation technology based on a network of high-orbit and low-orbit satellites around Mars. The measurement principle of Mars laser occultation is first introduced, which is that the atmospheric temperature and pressure are measured by analyzing the absorption spectrum characteristics of infrared carbon dioxide. Then, a detailed simulation process is described, including the establishment and validation of both the radiation intensity calculation model for laser occultation signals and the method for retrieving atmospheric parameters. A set of satellite payload parameters is also designed. The simulation results reveal that this method can accurately measure temperature and pressure at a vertical resolution of 100 m from 5 km to 50 km altitude of the Martian atmosphere with deviations of 0.43 K and 1.06%, respectively. It is indicated that the proposed laser occultation method can achieve effective detection of temperature and pressure and provide a promising approach for high vertical resolution profile detection of the Martian atmosphere in the future.

Winter Carbon Dioxide Measurement in Honeybee Hives

Sensor technologies have sufficiently advanced to provide low-cost devices that can quantify carbon dioxide levels in honeybee hives with high temporal resolution and in a small enough package for hive deployment. Recent publications have shown that summer carbon dioxide levels vary throughout the day and night over ranges that typically exceed 5000 ppm. Such dramatic changes in a measurable parameter associated with bee physiology are likely to convey information about the colony health. In this work, we present data from four UK-based hives collected through the winter of 2022/2023, with a focus on seeing if carbon dioxide can indicate when colonies are at risk of failure. These hives have been fitted with two Sensirion SCD41 photoacoustic non-dispersive infrared (NDIR) carbon dioxide sensors, one in the queen excluder, at the top of the brood box, and one in the crown board, at the top of the hive. Hive scales have been used to monitor the hive mass, and internal and external temperature sensors have been included. Embedded accelerometers in the central frame of the brood box have been used to measure vibrations. Data showed that the high daily variation in carbon dioxide continued throughout the coldest days of winter, and the vibrational data suggested that daily fanning may be responsible for restoring lower carbon dioxide levels. The process of fanning will draw in colder air to the hive at a time when the bees should be using their energy to maintain the colony temperature. Monitoring carbon dioxide may provide feedback, prompting human intervention when the colony is close to collapse, and a better understanding may contribute to discussions on future hive design.

Online Monitoring of Seawater Carbon Dioxide Based on an Infrared Rear Beam Splitter.

The ocean is one of the most extensive ecosystems on Earth and can absorb large amounts of carbon dioxide. Changes in seawater carbon dioxide concentrations are one of the most important factors affecting marine ecosystems. Excess carbon dioxide can lead to ocean acidification, threatening the stability of marine ecosystems and species diversity. Dissolved carbon dioxide detection in seawater has great scientific significance. Conducting online monitoring of seawater carbon dioxide can help to understand the health status of marine ecosystems and to protect marine ecosystems. Current seawater detection equipment is large and costly. This study designed a low-cost infrared carbon dioxide detection system based on molecular theory. Using the HITRAN database, the absorption spectra and coefficients of carbon dioxide molecules under different conditions were calculated and derived, and a wavelength of 2361 cm-1 was selected as the measurement channel for carbon dioxide. In addition, considering the interference effect of direct light, an infrared post-splitting method was proposed to eliminate the interference of light and improve the detection accuracy of the system. The system was designed for the online monitoring of carbon dioxide in seawater, including a peristaltic pump to accelerate gas-liquid separation, an optical path structure, and carbon dioxide concentration inversion. The experimental results showed that the standard deviation of the gas test is 3.05, the standard deviation of the seawater test is 6.04, and the error range is within 20 ppm. The system can be flexibly deployed and has good stability and portability, which can meet the needs of the online monitoring of seawater carbon dioxide concentration.

Analysis of the effect of reasonable close planting on respiration characteristics of alfalfa (Medicago sativa L.) artificial grassland

The degree of dense planting affects the respiration characteristics of alfalfa artificial grassland. In the process of alfalfa seed production, high plant and multibranch forage can be obtained by reasonable close planting. Therefore, an analysis method of the effect of reasonable close planting on respiration characteristics of garden alfalfa artificial grassland is put forward. In this method, the density characteristics of alfalfa planting were determined from three aspects of plant horizontal density, vertical density and three-dimensional density. The infrared carbon dioxide gas analyser was used to measure the carbon dioxide flux of the garden. The combined analysis method was constructed to obtain the respiration characteristics of alfalfa artificial grassland through multiple validations, so as to achieve the degree of impact on the respiration characteristics of the grassland analysis. The experimental results show that the proposed verification methods can explain the existence of growth redundancy and propose a method to reduce redundancy. Moreover, the proposed analysis method has more complete respiratory characteristics and the analysis results of photosynthesis and total vegetation yield are more consistent with the reality.

비분산적외선 CO2 센서를 위한 DBR기반의 패브리 페로-필터 설계 및 성능 연구

비분산적외선 CO2 센서를 위한 DBR기반의 패브리 페로-필터 설계 및 성능 연구

Effect of Temperature, Pressure and Humidity on Carbon Dioxide Concentration—Simulation Study

The growing application of infrared carbon dioxide (CO2) sensor now needs an accurate and precise measurement of human respired CO2 concentrations. CO2 concentration measurement is influenced by a number of environmental parameters. The objective of this study is to perform a simulation study on the list of environmental parameters which have a major influence on the precision and accuracy of the infrared CO2 sensor. Here, we designed a CO2 concentration estimation circuit that comprises temperature, pressure and humidity sensor, Arduino Uno, and liquid crystal display. Besides, a program is written and uploaded to the Arduino board to compute the CO2 concentration. A simple mathematical equation is employed to calculate the instantaneous CO2 concentrations with respective temperature, pressure and relative humidity. We observed a change in CO2 concentration from 31.11% to 30.60% and 21.25% to 26.18% corresponding to changes in temperature from 25oC to 30oC and pressure 21.53kPa to 26.52kPa, respectively while keeping the temperature (250C) and pressure (31.52kPa) constant with respect to each other. In addition, with a change in relative humidity from 28% to 30%, change in CO2 values (6.26% to 9.39%) were observed while temperature kept at 25 0C. Results show that pressure, temperature, and relative humidity have a significant effect on the output of CO2 concentration. Hence, this should not be underestimated while developing a CO2 sensor and barometric pressure, temperature, and relative humidity sensor should be integrated with CO2 sensor for automatic adjustment in CO2 concentration based on the current pressure, temperature and humidity in contrast to manual.

New sensor measures biological activity in soil at field scale in real time

New sensor measures biological activity in soil at field scale in real time

Interactive effects of soil moisture and temperature on soil respiration under native and non-native tree species in semi-arid forest of Delhi, India

We assessed the impacts of native and non-native tree species and seasonal variation on in situ soil respiration rates for four seasons. A portable infrared carbon dioxide (CO2) gas analyzer (Q-Box SR1LP) was used for in situ measurements. Seven tree species were selected, out of which three are native to Delhi ridge, viz., Vachellia leucophloea, Ficus religiosa and Millettia pinnata and four are non-native, viz., Albizia lebbeck, Prosopis juliflora, Azadirachta indica and Cassia fistula. Our results showed a significant seasonal variation and effect of native and non-native tree species on soil respiration. Soil respiration was high during monsoon and low in winter. The highest annual soil respiration was observed under the canopy of F. religiosa (18.72 µmol CO2 m−2 s−1 year−1) and lowest under A. indica (4.58 µmol CO2 m−2 s−1 year−1). The tree species showed the pattern: F. religiosa > A. lebbeck > P. juliflora > V. leucophloea > M. pinnata > C. fistula > A. indica. Soil respiration showed a positive correlation with soil moisture and temperature (P < 0.05) showing an interplay of both in controlling soil respiration. Our findings also highlighted the effect of litter quality and quantity on soil respiration as low C/N ratio and positive correlation of litter quantity with soil respiration enhanced its rate under F. religiosa. The maximum soil respiration under the canopy of native species than non-native ones suggests their importance in the vital ecosystem functions, and thus, in managing the forest ecosystem of Delhi.

SCFSen: A Sensor Node for Regional Soil Carbon Flux Monitoring

Estimation of regional soil carbon flux is very important for the study of the global carbon cycle. The spatial heterogeneity of soil respiration prevents the actual status of regional soil carbon flux from being revealed by measurements of only one or a few spatial sampling positions, which are usually used by traditional studies for the limitation of measurement instruments, so measuring in many spatial positions is very necessary. However, the existing instruments are expensive and cannot communicate with each other, which prevents them from meeting the requirement of synchronous measurements in multiple positions. Therefore, we designed and implemented an instrument for soil carbon flux measuring based on dynamic chamber method, SCFSen, which can measure soil carbon flux and communicate with each other to construct a sensor network. In its working stage, a SCFSen node measures the concentration of carbon in the chamber with an infrared carbon dioxide sensor for certain times periodically, and then the changing rate of the measurements is calculated, which can be converted to the corresponding value of soil carbon flux in the position during the short period. A wireless sensor network system using SCFSens as soil carbon flux sensing nodes can carry out multi-position measurements synchronously, so as to obtain the spatial heterogeneity of soil respiration. Furthermore, the sustainability of such a wireless sensor network system makes the temporal variability of regional soil carbon flux can also be obtained. So SCFSen makes thorough monitoring and accurate estimation of regional soil carbon flux become more feasible.

Study on effect of temperature and humidity on the CO2 concentration measurement

In the application of non dispersive infrared (NDIR) carbon dioxide (CO2) concentration measurement, we need avoid the interference factors (such as temperature, pressure, gas, fluctuation of the light source and dust pollution etc.). In the past experiments only single factor, such as temperature, is often emphasized to the influence on the measurement results, without considering the effect of multiple factors. In order to study the change of gas concentration with measurement parameters, we constructs a CO2 detecting device with a BM530 gas detecting module, TMD10 temperature and humidity sensor. The experimental results show that: there is a correlation between the two interference factors: temperature and humidity. With the decreasing temperature, gas concentration measurement value decreases too. In developing process of instruments, we can make correction of the concentration- temperature instead of that of the measurement results under different temperature and humidity conditions.

White-Cell 구조를 응용한 비분산 적외선 이산화탄소 센서의 온도특성

White-Cell 구조를 응용한 비분산 적외선 이산화탄소 센서의 온도특성

Field calibration of a cluster of low-cost commercially available sensors for air quality monitoring. Part B: NO, CO and CO2

Abstract In this work the performances of several field calibration methods for low-cost sensors, including linear/multi linear regression and supervised learning techniques, are compared. A cluster of either metal oxide or electrochemical sensors for nitrogen monoxide and carbon monoxide together with miniaturized infra-red carbon dioxide sensors was operated. Calibration was carried out during the two first weeks of evaluation against reference measurements. The accuracy of each regression method was evaluated on a five months field experiment at a semi-rural site using different indicators and techniques: orthogonal regression, target diagram, measurement uncertainty and drifts over time of sensor predictions. In addition to the analyses for ozone and nitrogen oxide already published in Part A [1], this work assessed if carbon monoxide sensors can reach the Data Quality Objective (DQOs) of 25% of uncertainty set in the European Air Quality Directive for indicative methods. As for ozone and nitrogen oxide, it was found for NO, CO and CO 2 that the best agreement between sensors and reference measurements was observed for supervised learning techniques compared to linear and multilinear regression.

보상용 적외선 센서를 사용한 비분산 적외선 이산화탄소 센서의 온도특성

보상용 적외선 센서를 사용한 비분산 적외선 이산화탄소 센서의 온도특성

Factors influencing surface CO2 variations in LPRU, Thailand and IESM, Philippines

Surface carbon dioxide concentrations were measured using a non-dispersive infrared carbon dioxide sensor at Lampang Rajabhat University from April to May 2013 and at the University of the Philippines-Diliman campus starting September 2013. Factors influencing the variations in these measurements were determined using multiple linear regression and a Lagrangian transport model. Air temperature and sea level pressure were the dominant meteorological factors that affect the CO2 variations. However, these factors are not enough. Surface CO2 flux and transboundary transport needs to be considered as well.

A Novel Solid State Non-Dispersive Infrared CO2 Gas Sensor Compatible with Wireless and Portable Deployment

This paper describes development of a novel mid-infrared light emitting diode (LED) and photodiode (PD) light source/detector combination and use within a non-dispersive infrared (NDIR) carbon dioxide gas sensor. The LED/PD based NDIR sensor provides fast stabilisation time (time required to turn on the sensor from cold, warm up, take and report a measurement, and power down again ≈1 second), longevity (>15 years), low power consumption and low cost. Described performance is compatible with “fit and forget” wireless deployed sensors in applications such as indoor air quality monitoring/control & energy conservation in buildings, transport systems, horticultural greenhouses and portable deployment for safety, industrial and medical applications. Fast stabilisation time, low intrinsic power consumption and cycled operation offer typical energy consumption per measurement of mJ's, providing extended operation using battery and/or energy harvesting strategies (measurement interval of ≈ 2 minutes provides >10 years operation from one AA battery). Specific performance data is provided in relation to measurement accuracy and noise, temperature performance, cross sensitivity, measurement range (two pathlength variants are described covering ambient through to 100% gas concentration), comparison with NDIR utilizing thermal source/pyroelectric light source/detector combination and compatibility with energy harvesting. Semiconductor based LED/PD processing together with injection moulded reflective optics and simple assembly provide a route to low cost high volume manufacturing.

Lung function measurement with multiple-breath-helium washout system

Multiple-breath-washout (MBW) measurements are regarded as a sensitive technique which can reflect the ventilation inhomogeneity of respiratory airways. Typically nitrogen is used as the tracer gas and is washed out by pure oxygen in multiple-breath-nitrogen washout (MBNW) tests. In this study, instead of using nitrogen, (4)He is used as the tracer gas with smaller gas density which may be able to reach deeper into our lungs in a given time and the helium washout results may be more sensitive to the ventilation inhomogeneity in small airways. A multiple-breath-helium-washout (MBHW) system developed for the lung function study is also presented. Quartz tuning forks with a resonance frequency of 32,768Hz have been used for detecting the change of the respiratory gas density. The resonance frequency of the quartz tuning fork decreases linearly with increasing density of the surrounding gas. Knowing the CO2 concentration from the infrared carbon dioxide detector, the helium concentration can be determined. Results from 14 volunteers (3 mild asthmatics, 4 tobacco smokers, 1 with asthma history, 1 with COPD history, 5 normal) have shown that mild asthmatics have higher ventilation inhomogeneity in either conducting or acinar airways (or both). A feature has been found in washout curve of single breaths from 4 tobacco smokers with different length of smoking history which may indicate the early stage of respiratory ventilation inhomogeneity in acinar airways.

Effect of microwave power on the morphology and optical property of zinc oxide nano-structures prepared via a microwave-assisted aqueous solution method

The effect of the microwave power on the morphology and optical properties of zinc oxide nanostructures prepared using a microwave-assisted aqueous solution method has been investigated. The ZnO nanostructures were synthesized from zinc chloride and sodium hydroxide mixed aqueous solutions exposed for 5 min to microwave radiation at four different powers, namely 150, 450, 700 and 1000 W. The morphologies of the samples have been characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the power of microwave radiation influenced the shape and size of the synthesized nanostructures. It is also found that the average particle size of nanostructures decreased with decreasing microwave power. The results of X-ray diffraction (XRD) showed that all the as-prepared ZnO nanostructures are in crystalline form with high purity. The infrared (IR) spectra indicated that the as-prepared nano ZnO product can be used as infrared gas sensors such as an infrared carbon dioxide (CO2) and/or CO sensor. Optical properties of the as-prepared ZnO nanostructures were investigated by UV–vis spectroscopy and showed that the optical properties of as-synthesized ZnO samples are sensitive to the variation of the power of microwave radiation.

Helium-oxygen reduces the production of carbon dioxide during weaning from mechanical ventilation

BackgroundProlonged weaning from mechanical ventilation has a major impact on ICU bed occupancy and patient outcome, and has significant cost implications.There is evidence in patients around the period of extubation that helium-oxygen leads to a reduction in the work of breathing. Therefore breathing helium-oxygen during weaning may be a useful adjunct to facilitate weaning. We hypothesised that breathing helium-oxygen would reduce carbon dioxide production during the weaning phase of mechanical ventilation.Materials/patients and methodsWe performed a prospective randomised controlled single blinded cross-over trial on 19 adult intensive care patients without significant airways disease who fulfilled criteria for weaning with CPAP. Patients were randomised to helium-oxygen and air-oxygen delivered during a 2 hour period of CPAP ventilation. Carbon dioxide production (VCO2) was measured using a near patient main stream infrared carbon dioxide sensor and fixed orifice pneumotachograph.ResultsCompared to air-oxygen, helium-oxygen significantly decreased VCO2 production at the end of the 2 hour period of CPAP ventilation; there was a mean difference in CO2 production of 48.9 ml/min (95% CI 18.7-79.2 p = 0.003) between the groups. There were no significant differences in other respiratory and haemodynamic parameters.ConclusionThis study shows that breathing a helium-oxygen mixture during weaning reduces carbon dioxide production. This physiological study supports the need for a clinical trial of helium-oxygen mixture during the weaning phase of mechanical ventilation with duration of weaning as the primary outcome.Trial registrationISRCTN56470948

Determination of photochemically produced carbon dioxide in seawater

An analytical system was developed to determine photochemically produced carbon dioxide in marine waters. Our system was designed to measure low levels of carbon dioxide by maintaining a closed system to prevent atmospheric contamination during sample preparation, irradiation, and analysis. To detect low levels of photoproduced carbon dioxide in seawater, background dissolved inorganic carbon (DIC) was removed before irradiation. To strip out DIC, samples were acidified to pH 3.0 (converting DIC to carbon dioxide) and bubbled with low carbon dioxide air. The pH was then readjusted back to the original value, and the resulting low‐DIC seawater samples were transferred pneumatically to air‐tight quartz tubes for irradiation. During analysis, samples were pneumatically transferred to a sample loop, injected, and acidified. Carbon dioxide was then stripped out, dried, and carried to a nondispersive infrared carbon dioxide analyzer. Calibration was done with a series of low concentration aqueous carbonate standards (0.05 to 3 µmol L−1). The detection limit, defined as the concentration corresponding to three times the standard deviation of the experimental blank (i.e., DIC‐stripped seawater), was ~60 nmol L−1. Method precision was largely dependent on the agreement between multiple injections from the same tube (&lt; ±2% relative standard deviation [RSD]) and the reproducibility between different tubes (±3% RSD). This method was used to measure carbon dioxide photoproduction in a variety of waters (e.g., estuarine, lake) including the first direct measurements in marine waters.

High‐frequency measurements of productivity of planktonic algae using rugged nondispersive infrared carbon dioxide probes

We have constructed a system based on commercially available inexpensive NDIR CO2 sensors to continuously monitor CO2 concentrations in water bodies. Here we demonstrate its use in a boreal humic lake. With the system, we collect high frequency data with a 10‐min time resolution for determination of CO2 consumption and production. We use and modify the computational methods commonly used in forest ecology to enable characterization of aquatic primary production. To demonstrate the advantages of the method, we present the results against the observations from the long‐term monitoring program applying traditional bottle methods. With the probes, we can detect a clear, photosynthesis‐driven daily pattern in the CO2 concentration and determine the CO2 consumption or production resulting in more than a 10‐fold improvement in the time resolution when compared with traditional incubation methods. The measuring frequency is high enough to determine the dependence of photosynthesis on irradiance. The high‐frequency data highlights the inherent problems of discrete bottle incubations and bring into question their reliability. Our free water approach yielded productivity and mineralization rates that were clearly higher than obtained with incubations.