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This paper suggests a Recalling Enhanced Recurrent Neural Network (RERNN) method for accurately predicting the performance and emissions of spark ignition (SI) engines. The RERNN method is an efficient neural network technique. The RERNN model is also trained using a better conjugate method that speeds up convergence by using a generalized Armijo search technique. The proposed method analyzes combustion phasing, exhaust temperature, engine-out emissions, burn duration, mean effective pressure, ignition lag, and maximum pressure rise rate. By then, the proposed technique is implemented on the MATLAB platform and is evaluated for its performance against existing techniques. The proposed RERNN method achieves a better outcome than other existing Seagull Optimization Algorithm (SOA), Grasshopper Optimization Algorithm (GOA), and Wild Horse Optimizer (WHO) techniques. The proposed method shows the error in carbon monoxide (CO) is 0.18% and carbon dioxide (CO2) is 0.29% at a high speed of 900 rpm compared with other existing approaches. • RERNN method designed for accurately predicting performance in SI engines. • The RERNN method is highlighted as an efficient neural network technique. • The RERNN model is trained using an improved conjugate method. • This approach contributes to a more holistic evaluation of engine performance. • The proposed RERNN method, implemented on the MATLAB platform. [ABSTRACT FROM AUTHOR]

The article describes a hard- and software controlled complex for gas-strain monitoring, consisting of stationary laser strainmeters and a laser nanobarograph, a stationary gas analyzer, and a weather station installed at Shultz Cape in the Sea of Japan; and a mobile shipboard complex, consisting of a gas analyzer and a weather station installed in a scientific research vessel. In the course of trial methodological measurements on these systems, general patterns were identified in the dynamics of greenhouse gases and deformation of the Earth's crust in the range of diurnal and semi-diurnal tides, and also in the range of ultra-low frequencies, caused by atmospheric wave processes and, possibly, individual tones of the Earth's eigen oscillations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Wildland Fire Science is the property of Journal of Wildland Fire Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this investigation, the tire pyrolysis fuel in (5, 10, 15, 20 vol. percent) has been examined in a single cylinder DI, four-stroke diesel engine with varying EGR rates (10, 20, and 30 percent), at various engine loads and constant speed of 1500 rpm. The study has expanded further in terms of studying the combined impact of EGR and magnetic conditioner effect. The trials have been carried out by utilizing a permanent Neodymium magnet with a field intensity of 8000 Gauss as a Dipole pole, which has been installed on the fuel line before the fuel injector. Because of the strong magnetic field this magnet creates, the hydrocarbons change their direction. As a result, during the combustion phase, the molecule interlocks with the oxygen, resulting in enhanced burning in the diesel engine. The improved combustion results in more combustion and less toxic gas emissions from the engine. The combining impacts of WTOP10 fuel addition +8000Gauss and EGR10 applications have demonstrated that the highest heat release rate and the maximum incylinder pressure have been mainly boosted. While the center of the heat release rates has shifted toward TDC, combustion durations have remained rather constant. Reasonable increases in the BTE and maximum decreases in the BSFC have been observed with WTOP10+8000Gauss10 percent EGR. Despite dramatic decreases in CO emissions, there have been increases at high engine loads. On the other hand, CO2 emissions have been marginally increased at all engine loads. [ABSTRACT FROM AUTHOR]

Relevance. Fuel oil application in power plants is characterized by increased values of underburning and anthropogenic emissions. One way to reduce anthropogenic emissions is the use of oil-water emulsions. Also, additional specialized additives are used to reduce anthropogenic emissions and improve fuel combustion characteristics. Aim. To determine the optimal fuel oil additive to reduce anthropogenic emissions and ignition delay times. Methods. The following additives: ION-M, Rosneft R503V3, Rosneft R502V1 (relative mass concentration 0.5%) were added to the water-oil fuel. The physicochemical properties of fuel oil M-100, as well as the elemental composition of CHNSO, were determined. The rheological characteristics of water-oil fuel compositions were established. Using high-speed photography, the droplet ignition delay times were determined. Using the gas analyzer, it was possible to prevent anthropogenic emissions. Results and conclusions. The results of the study showed that the additive based on a special combination of positively and negatively charged ions (ION M) reduces ignition delay times by 20–60%, when the gas temperature varies in the range from 700 to 900 °C. The addition of the additive based on fatty vegetable acids (P502B3) reduced the ignition delay times by 7–10%, when the temperature changed in the range from 700 to 900 °C relative to water-oil fuel. It was found that when using the P502B1 additive in water-oil fuel, it was possible to reduce the ignition delay times by 15–50%. It was determined that in the presence of combustion catalysts, water binds with heavy hydrocarbons and thus the release of volatile substances occurs faster, i. e. the supplied heat is not wasted on heating water into droplets, but evenly affects the entire volume of fuel. The results of the study of anthropogenic emissions showed that the use of additives when burning water-oil fuel reduces the concentrations of CO, CO2, NO, SO2 by 8, 6, 10 and 13%, respectively, compared to fuel oil.

According to the Air Quality Live Index (AQLI), Indonesia's air quality has continued to deteriorate in the last two decades, so Indonesia is officially ranked 17th as the country with the worst air quality in the world. This is due to the population explosion in Indonesia causing industrial activity to also increase. The high levels of exhaust emissions in vehicles, of course, requires the need for technology to measure vehicle exhaust gases to reduce the impact of air pollution. However, the procurement of exhaust emission test equipment is still expensive, so only certain class workshops have this tool. In addition, the reading results of the vehicle's OBD (On Board Diagnostic) system are only able to display the condition or reading value of the Lambda sensor because other gas sensors readings such as CO2, HC, and CO cannot be displayed on the OBD reading results. The purpose of this study is to describe the design of the tool and the results of measuring CO and HC levels through the Blynk application. Research methods that use several gas sensors, such as MQ-7 and TGS-2602 (CO gas) and MQ-2 and TGS-2611 (HC gas), are then compared with the measurement results of a standard gas analyzer. The results showed that the MQ-7 value is close to the accuracy at 1000 rpm and 5000 rpm, namely 99.68% and 99.49%, while the level of accuracy at 3000 rpm is 99.37%. The TGS-2602 sensor at 1000 rpm only has the best accuracy and accuracy, namely 99.67% and 99.77%. The level of accuracy of the MQ-2 sensor has the best value at 1000 rpm rotation, which is 95.71% and the level of accuracy has the highest value at 7000 rpm rotation, which is 100%. For the level of accuracy of the TGS-2611 sensor, it has an accuracy level of 1000 rpm rotation of 94.65% and the level of accuracy of the sensor obtains very good values ​​at 1000 rpm, 7000 rpm, and 9000 rpm rotation of 100%.

The single-cylinder, four-stroke, overhead valve Biggs Stratton engine was studied for the possible toxinity with the view of solving the environmental pollution problem related to the internal combustion engine emissions. As an assessment of toxicity, the data recorded (INFRACAR 5M3T) in the exhaust gases of the power unit NOx, CO and CH was used. Evaluation of the toxicity of the engine running under load was carried out by testing (CARTEC LPS 2510 dynamometer) an engine-equipped vehicle of simplified design (buggy). It was shown that the presence of CO, CH and NOx in the exhaust gases is affected not only by the presence of alcohol in gasoline, but also by the crankshaft speed. It was found that the proportion of CH in the exhaust gases of the power unit running on gasoline is lower than the maximum allowable content of hydrocarbons in the exhaust gases of gasoline engines not equipped with a neutralization system. According to the data obtained from bench tests, it follows that the proportion of CH in the exhaust gases of a gasoline-fueled engine is on average 48% higher than in the exhaust gases of an engine fed with a gasoline-alcohol mixture. It was shown that a significant increase in power at the wheel does not lead to a sharp increase in the CH content in the exhaust gases. The proportion of CH in the exhaust gases in the obtained speed range is a constant value.

The constant emission of polluting gases is causing an urgent need for timely detection of harmful gas mixtures in the atmosphere. A method and algorithm of the determining spectral composition of gas with a gas analyzer using an artificial neural network (ANN) were suggested in the article. A small closed gas dynamic system was designed and used as an experimental bench for collecting and quantifying gas concentrations for testing the proposed method. This device was based on AS7265x and BMP180 sensors connected in parallel to a 3.3 V compatible Arduino Uno board via QWIIC. Experimental tests were conducted with air from the laboratory room, carbon dioxide (CO2), and a mixture of pure oxygen (O2) with nitrogen (N2) in a 9:1 ratio. Three ANNs with one input, one hidden and one output layer were built. The ANN had 5, 10, and 20 hidden neurons, respectively. The dataset was divided into three parts: 70% for training, 15% for validation, and 15% for testing. The mean square error (MSE) error and regression were analyzed during training. Training, testing, and validation error analysis were performed to find the optimal iteration, and the MSE versus training iteration was plotted. The best indicators of training and construction were shown by the ANN with 5 (five) hidden layers, and 16 iterations are enough to train, test and verify this neural network. To test the obtained neural network, the program code was written in the MATLAB. The proposed scheme of the gas analyzer is operable and has a high accuracy of gas detection with a given error of 3%. The results of the study can be used in the development of an industrial gas analyzer for the detection of harmful gas mixtures. [ABSTRACT FROM AUTHOR]

The article describes a hard- and software controlled complex for gas-strain monitoring, consisting of stationary laser strainmeters and a laser nanobarograph, a stationary gas analyzer, and a weather station installed at Shultz Cape in the Sea of Japan; and a mobile shipboard complex, consisting of a gas analyzer and a weather station installed in a scientific research vessel. In the course of trial methodological measurements on these systems, general patterns were identified in the dynamics of greenhouse gases and deformation of the Earth’s crust in the range of diurnal and semi-diurnal tides, and also in the range of ultra-low frequencies, caused by atmospheric wave processes and, possibly, individual tones of the Earth’s eigen oscillations.

The paper considers the uncooled photodetectors based on GalnAsSb/GaAlAsSb heterostructures, which can be applied in precision diode laser spectroscopy. The spectral sensitivity range of photodetectors with a photosensitive area diameter of 1.0 mm and 2.0 mm is 1.0–2.4 μm. The current monochromatic sensitivity at the wavelength of 2.1 μm has a value of 1.0 A/W without bias. The capacity reaches 375 pF with a photosensitive area diameter of 1.0 mm and 800–5000 pF with 2 mm. The modern gas analyzers based on diode lasers and developed photodetectors for medical screening diagnostics by analyzing the gas compositions of exhaled air, for control of impurity gases in the process of rectification of inorganic hydrides, control of methane leaks in gas pipelines, as well as for registration of exhaust gases of a moving car are presented. [ABSTRACT FROM AUTHOR]

The object of the research is to ensure environmental safety and maximum efficiency of fuel burning equipment. Energy facilities (thermal power plant, boiler houses) are among the biggest air polluters in the city. Nitrogen oxides (NO, NO2, NOx) occupy a significant place among the toxic gases contained in the flue gases of fuel-burning equipment. These substances have a negative impact on the ecological state of the city and are regulated by the Order of the Ministry of Natural Resources of Ukraine dated 27.06.2006 No. 309 on the approval of standards for maximum permissible emissions of pollutants from stationary sources. The principles of measurement unity are considered, including the presentation of measurement results in standard units (ppm, mg/m³). Conversion from volume concentration (ppm) to mass (mg/m³) is given. Measurements of the concentration of nitrogen oxides were carried out. In the course of research, instrumental measuring tools were used, which made it possible to obtain the values of nitrogen dioxide concentrations in gas boiler flue emissions. In particular, the average maximum concentrations of the main pollutants exceed 62.58 mg/m³. Analyzing the concentration of flue gases allows to determine the concentration of pollutants and to adjust the optimal operation of the equipment as much as possible, achieving a reduction in emissions and compliance with the approved emission standards. Obtained data on background concentrations of nitrogen dioxide in the city of Kyiv, amounting to 1.33 MPC. Using the data of instrumental measurements with the method of calculating concentrations of harmful substances in the atmospheric air and background concentrations, a map of emission dispersion was created. Fields of surface concentrations were plotted on the scattering map, which makes it possible to compare the obtained values with the hygienic standards of atmospheric air. By combining instrumental measurement methods and calculation methods, the volume of emissions was determined and the impact on atmospheric air pollution of the city was assessed. [ABSTRACT FROM AUTHOR]

Copyright of ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M. is the property of Knowledge E DMCC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This review paper illustrates the recommended monitoring technologies for the detection of various greenhouse gaseous emissions for solid waste thermochemical reactions, including incineration, pyrolysis, and gasification. The illustrated gas analyzers are based on the absorption principle, which continuously measures the physicochemical properties of gaseous mixtures, including oxygen, carbon dioxide, carbon monoxide, hydrogen, and methane, during thermochemical reactions. This paper illustrates the recommended gas analyzers and process control tools for different thermochemical reactions and aims to recommend equipment to increase the sensitivity, linearity, and dynamics of various thermochemical reactions. The equipment achieves new levels of on-location, real-time analytical capability using FTIR analysis. The environmental assessment study includes inventory analysis, impact analysis, and sensitivity analysis to compare the mentioned solid waste chemical recycling methods in terms of greenhouse gaseous emissions, thermal efficiency, electrical efficiency, and sensitivity analysis. The environmental impact assessment compares each technology in terms of greenhouse gaseous emissions, including CO2, NOx, NH3, N2O, CO, CH4, heat, and electricity generation. The conducted environmental assessment compares the mentioned technologies through 15 different emission-related impact categories, including climate change impact, ecosystem quality, and resource depletion. The continuously monitored process streams assure the online monitoring of gaseous products of thermochemical processes that enhance the quality of the end products and reduce undesired products, such as tar and char. This state-of-the-art monitoring and process control framework provides recommended analytical equipment and monitoring tools for different thermochemical reactions to optimize process parameters and reduce greenhouse gaseous emissions and undesired products. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper reports on a compact and lightweight sensor for analysis of gases/vapors by means of a MEMS-based pre-concentrator coupled to a miniaturized infrared absorption spectroscopy (IRAS) module. The pre-concentrator was utilized to sample and trap vapors in a MEMS cartridge filled with sorbent material and to release them once concentrated by fast thermal desorption. It was also equipped with a photoionization detector for in-line detection and monitoring of the sampled concentration. The vapors released by the MEMS pre-concentrator are injected into a hollow fiber, which acts as the analysis cell of the IRAS module. The miniaturized internal volume of the hollow fiber of about 20 microliters keeps the vapors concentrated for analysis, thus allowing measurement of their infrared absorption spectrum with a signal to noise ratio high enough to identify the molecule, despite the short optical path, starting from sampled concentration in air down to parts per million. Results obtained for ammonia, sulfur hexafluoride, ethanol and isopropanol are reported to illustrate the sensor detection and identification capability. A limit of identification (LoI) of about 10 parts per million was validated in the lab for ammonia. The lightweight and low power consumption design of the sensor allowed operation onboard unmanned aerial vehicles (UAVs). The first prototype was developed within the EU Horizon 2020 project ROCSAFE for the remote assessment and forensic examination of a scene in the aftermath of industrial or terroristic accidents. [ABSTRACT FROM AUTHOR]

The work analyzes the main ways to increase the sensitivity and selectivity of optical methods of gas analysis. A mathematical model of multiple reflection of optical radiation in a gas chamber is obtained and the main factors influencing the sensitivity of the gas analyzer are determined.

The eddy covariance technique (EC) is used at hundreds of field sites worldwide to measure trace gas exchange between the surface and the atmosphere. Data quality and correction methods for EC have been studied empirically and theoretically for many years. The recent development of new gas analyzers has led to an increase in technological options for users. Open-path (no inlet tube) and closed-path (long inlet tube) sensors have been used for a long time, whereas enclosed-path (short inlet tube) sensors are relatively new. We tested the comparability of fluxes calculated from five different gas analyzers including two open-path (LI-7500 A from LI-COR, IRGASON from Campbell), two enclosed-path (CPEC200 from Campbell, LI-7200 from LI-COR), and one closed-path (2311-f from Picarro) analyzers, which were all located on a single tower at an irrigated alfalfa field in Davis, CA. To effectively compare sensors with different tube characteristics we used three different spectral correction methods. We found that all sensors, regardless of type, can be used to measure fluxes if appropriate corrections are applied and quality control measures are taken. However, the comparability strongly depended on the gas (CO2 or H2O) and the correction method. Average differences were below 4% for CO2 fluxes using any spectral correction method, but for H2O average differences were between 4% and 13% for the different methods. The magnitude of corrections also varied strongly, especially for water vapor fluxes. This study does not identify the best sensor, but rather weighs the benefits and difficulties of each sensor and sensor type. Our findings show that enclosed and closed-path gas analyzers that measure water vapor with inlet tubes experience large high frequency attenuation and should be corrected with empirical correction methods. This information presented here about different the diverse sensors be considered by investigators when choosing a sensor for a site or when analyzing EC measurements from multiple sites.

The use of fossil fuels in transportation equipment, especially motorized vehicles, will have an extraordinary effect on air pollution. Therefore, air pollution becomes very important problem today. The amount of percentage of air pollution from transportation sources in Indonesia is 70.5 % CO, 18.34 % HC, 8.89 % NOx, 0.88 % SOx, and 1.33 % particulate matter. Given the danger of exhaust emissions, especially carbon monoxide which can cause death for humans who inhale it, therefore efforts are needed to control air pollution from motorized vehicles. There are several methods that can be used, one of which is to use adsorbents. Activated carbon can be used as an adsorbent. One alternative that can be applied as an adsorbent is peat soil-activated carbon which is abundant and easy to make as an adsorbent. By utilizing the abundant peat-soil which is a great potential area of Banjarmasin, South Kalimantan. In this experimental study; model l has a diameter of 20 mm, model 2 has an outside diameter of 20 mm and an inside diameter of 10 mm, and model 3 is without adsorbent. The length of this model is the same. Testing with a 2005 Honda Kharisma motor vehicle with an engine speed of 1000, 2000, and 3000 rpm. CO and HC emission tests using a gas analyzer were carried out. Testing was also carried out using a dyno test to determine the engine performance of a motorcycle that was installed with an adsorbent on the exhaust gas. The results showed that peat soil adsorbents with perforated circle designs can reduce CO gas emissions by 55 % compared to the others. Besides that, the use of peat soil adsorbents with hollow circle designs can also reduce HC gas emissions by 3.51 %. The results of the engine performance test showed that there was no significant effect of using this adsorbent on torque and power. In conclusion, peat soil adsorbents used to reduce exhaust emissions in motorized vehicles can be applied. [ABSTRACT FROM AUTHOR]

This paper reports on a compact, portable, and selective chemical sensor for hazardous vapors at trace levels, which is under development and validation within the EU project H2020 "RISEN". Starting from the prototype developed for a previous EU project, here, we implemented an updated two-stage purge and trap vapor pre-concentration system, a more compact MEMS- based fast gas-chromatographic separation module (Compact-GC), a new miniaturized quartz-enhanced photoacoustic spectroscopy (QEPAS) detector, and a new compact laser source. The system provides two-dimensional selectivity combining GC retention time and QEPAS spectral information and was specifically designed to be rugged, portable, suitable for on-site analysis of a crime scene, with accurate response in few minutes and in the presence of strong chemical background. The main upgrades of the sensor components and functional modules will be presented in detail, and test results with VOCs, simulants of hazardous chemical agents, and drug precursors will be reported and discussed. [ABSTRACT FROM AUTHOR]

The results of the determination of sulfur-containing compounds in atmospheric air polluted by products of the depressurization of a product pipeline with gas condensate are presented. Hydrogen sulfide was determined online using mobile automatic control stations and by photometry in a stationary laboratory. Organic sulfur-containing compounds (mercaptans, sulfides, disulfides) were identified by chromatography–mass spectrometry. It was found that the results of the analysis obtained in the automatic mode reflect the total content of hydrogen sulfide and some organosulfur compounds. [ABSTRACT FROM AUTHOR]

Objective: Maximal oxygen consumption (VO2max) can be estimated using maximal or sub-maximal tests, by direct or indirect methods.The Queen’s College Step Test (QCT) is used very frequently to estimate VO2max due to its simple, safe, quick and feasible approach. Originally the QCT was developed for the white race population, which is different from the Indian population in terms of ethnicity. So the present study was conducted to validate the applicability of the QCT to indirectly estimate VO2max in Indian adults. Material and Methods: A total of 419 apparently healthy students (male and female) were recruited for the study by the RUHS College of Medical Sciences (RUHS-CMS), Jaipur from January 2019 to March 2020 by random number table generator sampling. Direct estimation of VO2max was performed by sub-maximal exercise testing on a treadmill using a gas analyzer, while VO2max was indirectly predicted by the standard QCT protocol. The collected data were entered into Microsoft Excel and analyzed using unpaired student t-test, analysis of variance (ANOVA), and regression analysis. Results: The average directly measured VO2max (ml/kg/min) in males was 45.30±7.35, and for women was 35.71±5.29, and predicted by the QCT was 49.01 for males and 38.83±5.30 for females. The difference between the measured and predicted mean VO2max (PVO2max) values was statistically significant (p-value

Starting from Quartz-Enhanced Photo-Acoustic Spectroscopy (QEPAS), we have explored the potential of a tightly linked method of gas/vapor sensing, from now on referred to as Tuning-Fork-Enhanced Photo-Acoustic Spectroscopy (TFEPAS). TFEPAS utilizes a non-piezoelectric metal or dielectric tuning fork to transduce the photoacoustic excitation and an optical interferometric readout to measure the amplitude of the tuning fork vibration. In particular, we have devised a solution based on Additive Manufacturing (AM) for the Absorption Detection Module (ADM). The novelty of our solution is that the ADM is entirely built monolithically by Micro-Metal Laser Sintering (MMLS) or other AM techniques to achieve easier and more cost-effective customization, extreme miniaturization of internal volumes, automatic alignment of the tuning fork with the acoustic micro-resonators, and operation at high temperature. This paper reports on preliminary experimental results achieved with ammonia at parts-per-million concentration in nitrogen to demonstrate the feasibility of the proposed solution. Prospectively, the proposed TFEPAS solution appears particularly suited for hyphenation to micro-Gas Chromatography and for the analysis of complex solid and liquid traces samples, including compounds with low volatility such as illicit drugs, explosives, and persistent chemical warfare agents. [ABSTRACT FROM AUTHOR]

The object of research is the technological process of burning pellets in boilers. Using solid fuel boilers on pellets for heat production, they are trying to reduce dependence on hydrocarbon energy resources. Often such boilers are installed for autonomous heating of schools and other communal facilities. One of the most problematic areas is the analysis of the environmental impact when using pellets as a fuel for municipal boiler houses in urban areas. Boilers operating on solid fuels are characterized by a larger range of pollutants, as well as large values of concentrations emitted through the chimney. In the course of the research, instrumental measurement tools were used, which made it possible to obtain the value of the concentrations of pollutants in the emissions from the chimneys of boilers. In particular, the average maximum concentrations of the main pollutants were: nitrogen dioxide – 271.78 mg/m³, carbon emissions – 1935.44 mg/m³, sulfur dioxin – 13.37 mg/m³, suspended solids, undifferentiated in composition (dust, ash) – 93.2 mg/m³. Using the data of instrumental measurements according to the method of calculating the concentrations of harmful substances in the atmospheric air, a map of the dispersion of emissions was created. Surface concentration fields were plotted on the scatter map, which makes it possible to compare the obtained values with hygienic normative atmospheric air. This makes it possible to determine the distance where the highest value of pollutants from the emission source is recorded. By combining instrumental measurement methods and calculation methods, the volumes and nomenclature of emissions were determined. This made it possible to determine the amount of pollutants per unit mass of burned pellets in the boiler. Using the conducted studies and theoretical calculations for various types of fuel in the production of heat, this will allow assessing their impact on air pollution and reducing the risk of harm to human health. [ABSTRACT FROM AUTHOR]

Coke reactivity index and coke strength after reaction traditionally evaluated by reacting coke with carbon dioxide in standard condition. Several testing standard/methods viz., American society for testing and materials, Japan Industrial Standard, Bureau of Indian Standards, and International Organization Standard exists, which are used worldwide to measure the hot strength of metallurgical coke. In the Indian operation of Iron and steel plants, coke strength after reaction is a vital coke quality parameter for assessing the relative strength of coke for the blast furnace-efficient operation. The mentioned testing methodology is lengthy and takes significant time (~7 h) to complete a single test. Consequently, it needs to develop a method for the coke reactivity index, predicting almost real-time data. A newly developed methodology by infrared gas analyzer was used for developed and validated with coke oven plant coke samples. Result confirmed that the predicted and measured coke CRI with the Nippon Steel Corporation method has a strong positive relationship (R2 = 0.92). The results also confirmed the interrelationship between the predicted and actual coke CSR. The developed model can provide a real-time coke reactivity index and estimate the coke CSR within 10 min of reaction time. [ABSTRACT FROM AUTHOR]

This paper has investigated the nanostructured samples of zinc oxide intended for use as a gas sensor. Experimental samples were obtained by the economical sol-gel method, suitable for large-scale production. The dependence of the efficiency of gas sensors based on zinc oxide on temperature was established. The electrical properties of experimental samples were investigated in the air in the range of values of the initial voltage of 5–30 V and at temperatures of 320, 370, and 450 K. It was established that the current-voltage characteristic for nanosized zinc oxide is non-ohmic, but the nature of the curves can change due to an increase in the operating temperature. The obtained experimental dependences are explained by the peculiarities of the morphology of the obtained nanostructured zinc oxide, which affects the value of the contact resistance in the structure. A large number of nanoscale particles leads to an increase in the number of energy barriers, which negatively affects the sensitivity of experimental samples to the gaseous medium. The study of the sensitivity of samples to the established gaseous medium, namely 100 ppm CO, was carried out. The electrical conductivity of zinc oxide is determined by oxygen vacancies that are electron donors, and, accordingly, the conductivity activation energy is determined by the donor levels formed by vacancies in the ZnO forbidden zone. During heating, there is a decrease in the resistance of the sample with increasing temperature; electrical conductivity is determined by the thermal generation of electrons. Understanding the dependence of the sensor sensitivity on temperature and the use of sensitive ZnO layers of different morphology will make it possible to recognize gaseous components in a complex mixture. [ABSTRACT FROM AUTHOR]

Stationary nonlaser gas analyzers have been designed since the 1990s at the Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch, Russian Academy of Sciences, on the basis of the classical differential absorption method for monitoring the content of nitrogen and sulfur oxides in exhaust gases of thermal power plants, which burn natural gas, coal, and fuel oil. The operation of gas analyzers at Russian thermal power plants has shown their high sensitivity, reliability, and ease of maintenance. Based on the differential optical absorption spectroscopy and UV LEDs, a prototype of a portable energy-independent gas analyzer has been designed. It is an effective tool for simultaneous long-path measurements of concentrations of several atmospheric gases. An atomic absorption mercury analyzer has been created, where a capillary lamp with mercury of natural isotopic composition and the transverse Zeeman effect is used as a radiation source. A technique for detecting mercury in different media has been designed; the sensitivity of the analyzer is 14 ng/m3. Its applicability to multipurpose mercury monitoring is shown. [ABSTRACT FROM AUTHOR]

The article presents materials on use of ultrasonic waves to reduce the smoke and toxicity of diesel engine exhaust gases. The results of the experiments are presented. The hypothesis on the reduction of smoke and toxicity of the exhaust gas due to the acceleration of the coagulation of its particles under the action of ultrasound has been confirmed. The dependences of the degree of turbidity of a diesel car on the number of revolutions of the engine crankshaft per minute and the dependence of the content of harmful impurities in the exhaust gases, without exposure and under the influence of ultrasound, at various revolutions of the engine crankshaft per minute, have been obtained. In addition, graphs of the amount of settled soot in an ultrasonic device on the number of engine revolutions per minute were obtained experimentally without and under the influence of ultrasound. [ABSTRACT FROM AUTHOR]

The special mobile diagnostic group (MDG) is formed in the Federal State Budgetary Establishment «33 Central Scientific Research Test Institute» of the Ministry of Defenсe of the Russian Federation (hereinafter referred to as the institute) to perform tasks related to the radiation and chemical (RCh) control of different objects, to ensure RCh safety and security of mass events, as well as to perform special tasks of RCh examination of samples of all kinds. The purpose of the work is to consider the design, capabilities and organization of the mobile complex of chemical control (MCCC), which is the basis of the technical equipment of the MDG. The complex is created on the basis of Ford-Transit off-road vehicle with the equipment for the MDG and a container installed on a two-axle platform, where the equipment for the MDG is located. The complex is equipped with modern analytical equipment, means of communications, navigation, information processing and automatic meteorological observation, with the life support kit, autonomous power and water supply systems, exhaust ventilation, heating and air conditioning systems. The technical characteristics of the MCCC are as follows: crew – 8 people; preparation time – no more than 60 minutes; time for the preliminary identification of substances detected by the mobile group (from the moment of arrival) – no more than 60 minutes; the lower limit of detection of toxic chemicals in environmental objects – at the maximum concentration limit; time of confirming identification of detected toxic chemicals (from the moment of delivery of samples) – no more than 180 minutes; cruising range – up to 700 km. The methodological apparatus is also developed, that ensures the functioning of the MCCC crew during the performance of wide range of tasks of the MDG. Subsequently, this methodological apparatus has been repeatedly expanded and refined based on the results of the complex's participation in ensuring the RCh security of various mass events. The algorithm of carrying out special chemical control by technical means of the MCCC complex is presented in the article. The complex is capable of detecting both low-hazard and emergency concentrations of practically all known toxic chemicals in various samples, and identifying these substances in environmental objects.

The article presents materials on use of ultrasonic waves to reduce the smoke and toxicity of diesel engine exhaust gases. The results of the experiments are presented. The hypothesis on the reduction of smoke and toxicity of the exhaust gas due to the acceleration of the coagulation of its particles under the action of ultrasound has been confirmed.

• Novel lower-cost eddy covariance setups were compared to a conventional eddy covariance setup. • Lower-cost setups reproduced well ecosystem carbon and evapotranspiration dynamics. • Uncertainty of lower-cost eddy covariance is higher than in conventional eddy covariance. • Lower-cost setups have the potential to increase spatial replication in eddy covariance studies. Novel, lower-cost setups of eddy covariance systems may offer a potential solution to the spatial replication problem of single flux towers. Prior to their widespread application, it is essential to conduct comprehensive testing against conventional eddy covariance setups to ensure the accuracy and precision of the measurements. In this study, we performed a comparison between three lower-cost eddy covariance setups based on lower-cost (approximately 33 % of the cost of a conventional infrared gas analyzer) slow-response carbon dioxide (CO 2) and relative humidity (RH) sensors and a conventional eddy covariance setup for measuring carbon dioxide and evapotranspiration (ET) fluxes above a monocropping agricultural site in Northern Germany. The fluxes measured by these setups were further compared with a fourth lower-cost eddy covariance setup in an adjacent agroforestry field. The three lower-cost setups demonstrated satisfactory agreement with the conventional eddy covariance setup, with the slopes of the linear regression models for the 30-min flux time series ranging from 0.95 to 1.05 (R2 from 0.88 to 0.92) for CO 2 fluxes and from 0.78 to 0.99 (R2 from 0.7 to 0.85) for latent heat (LE) fluxes. All lower-cost setups reproduced well diel and seasonal CO 2 flux and ET dynamics. Furthermore, the lower-cost eddy covariance setups were able to measure ecosystem differences between agroforestry and monocropping, with differences in fluxes between both land uses being higher than differences between different setups. Despite the necessity for enhanced spectral corrections and the higher uncertainty associated with the lower-cost setups, the findings of this study illustrate the potential of these lower-cost setups to validate and replicate conventional eddy covariance setups, thereby enhancing the spatial representativity of measurements of energy, trace gases and momentum exchanges between terrestrial ecosystems and the atmosphere. [ABSTRACT FROM AUTHOR]

This paper reports on a compact and lightweight sensor for analysis of gases/vapors by means of a MEMS-based pre-concentrator coupled to a miniaturized infrared absorption spectroscopy (IRAS) module. The pre-concentrator was utilized to sample and trap vapors in a MEMS cartridge filled with sorbent material and to release them once concentrated by fast thermal desorption. It was also equipped with a photoionization detector for in-line detection and monitoring of the sampled concentration. The vapors released by the MEMS pre-concentrator are injected into a hollow fiber, which acts as the analysis cell of the IRAS module. The miniaturized internal volume of the hollow fiber of about 20 microliters keeps the vapors concentrated for analysis, thus allowing measurement of their infrared absorption spectrum with a signal to noise ratio high enough to identify the molecule, despite the short optical path, starting from sampled concentration in air down to parts per million. Results obtained for ammonia, sulfur hexafluoride, ethanol and isopropanol are reported to illustrate the sensor detection and identification capability. A limit of identification (LoI) of about 10 parts per million was validated in the lab for ammonia. The lightweight and low power consumption design of the sensor allowed operation onboard unmanned aerial vehicles (UAVs). The first prototype was developed within the EU Horizon 2020 project ROCSAFE for the remote assessment and forensic examination of a scene in the aftermath of industrial or terroristic accidents.

This review paper illustrates the recommended monitoring technologies for the detection of various greenhouse gaseous emissions for solid waste thermochemical reactions, including incineration, pyrolysis, and gasification. The illustrated gas analyzers are based on the absorption principle, which continuously measures the physicochemical properties of gaseous mixtures, including oxygen, carbon dioxide, carbon monoxide, hydrogen, and methane, during thermochemical reactions. This paper illustrates the recommended gas analyzers and process control tools for different thermochemical reactions and aims to recommend equipment to increase the sensitivity, linearity, and dynamics of various thermochemical reactions. The equipment achieves new levels of on-location, real-time analytical capability using FTIR analysis. The environmental assessment study includes inventory analysis, impact analysis, and sensitivity analysis to compare the mentioned solid waste chemical recycling methods in terms of greenhouse gaseous emissions, thermal efficiency, electrical efficiency, and sensitivity analysis. The environmental impact assessment compares each technology in terms of greenhouse gaseous emissions, including CO2, NOx, NH3, N2O, CO, CH4, heat, and electricity generation. The conducted environmental assessment compares the mentioned technologies through 15 different emission-related impact categories, including climate change impact, ecosystem quality, and resource depletion. The continuously monitored process streams assure the online monitoring of gaseous products of thermochemical processes that enhance the quality of the end products and reduce undesired products, such as tar and char. This state-of-the-art monitoring and process control framework provides recommended analytical equipment and monitoring tools for different thermochemical reactions to optimize process parameters and reduce greenhouse gaseous emissions and undesired products.

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The most applicable ICE monitoring method is selective control followed by individual corrections for the current technical condition. The combination of a gas analyzer installed individually in each collector, a motor tester, and a loader which provides test modes makes it possible to recognize failures of exhaust and other systems with high accuracy and to assign an individual corrective action to ensure specified environmental and economic parameters. We developed a generalized mathematical model of changes in the composition of exhaust gases depending on changes in the resistance of the catalytic converter, the spark gap of the spark plug, and the capacity of the electromagnetic nozzle.

The advantages and disadvantages of gas sensors for measuring the content of toxic substances in work zone air are reviewed. The main standards and normative documents outlining the requirements for the instrumentation for measuring the content of harmful substances in work zone air are considered. Experimental setup for investigating the characteristics of amperometric sensors, measurement procedure and experimental results are described. Comparative analysis of the characteristics of sensors produced by various manufacturers are presented. Recommendations are given on the practical use of the obtained data for developing measuring instruments satisfying the requirements of the domestic regulations. [ABSTRACT FROM AUTHOR]

When mining hard coal the underground method is prevailed. This method provides a higher quality of the mineral. Methane emissions occur in coal mines during the development of gasbearing seams. These emissions are the reason for the formation of an explosive mixture when mixed with mine air, and also contribute to the spontaneous combustion of coal. Methane alarms are used to monitor the mine atmosphere. Thermocatalytic sensor is the main element of such a gas analyzer. The sensor is placed in a breathable housing. This body is called a flame arrester. This article discusses the possibility of replacing the material used for the manufacture of a flame arrester. The basis of the existing material is nickel powder. It is proposed to replace it with a cermet bond. The composition of the ceramic material of the part is developed by the author and presented in the article. Replacement of material will lead to a significant reduction in the cost of the part and simplification of the manufacturing technology.

This paper reports on a compact, portable, and selective chemical sensor for hazardous vapors at trace levels, which is under development and validation within the EU project H2020 “RISEN”. Starting from the prototype developed for a previous EU project, here, we implemented an updated two-stage purge and trap vapor pre-concentration system, a more compact MEMS- based fast gas-chromatographic separation module (Compact-GC), a new miniaturized quartz-enhanced photoacoustic spectroscopy (QEPAS) detector, and a new compact laser source. The system provides two-dimensional selectivity combining GC retention time and QEPAS spectral information and was specifically designed to be rugged, portable, suitable for on-site analysis of a crime scene, with accurate response in few minutes and in the presence of strong chemical background. The main upgrades of the sensor components and functional modules will be presented in detail, and test results with VOCs, simulants of hazardous chemical agents, and drug precursors will be reported and discussed.

Starting from Quartz-Enhanced Photo-Acoustic Spectroscopy (QEPAS), we have explored the potential of a tightly linked method of gas/vapor sensing, from now on referred to as Tuning-Fork-Enhanced Photo-Acoustic Spectroscopy (TFEPAS). TFEPAS utilizes a non-piezoelectric metal or dielectric tuning fork to transduce the photoacoustic excitation and an optical interferometric readout to measure the amplitude of the tuning fork vibration. In particular, we have devised a solution based on Additive Manufacturing (AM) for the Absorption Detection Module (ADM). The novelty of our solution is that the ADM is entirely built monolithically by Micro-Metal Laser Sintering (MMLS) or other AM techniques to achieve easier and more cost-effective customization, extreme miniaturization of internal volumes, automatic alignment of the tuning fork with the acoustic micro-resonators, and operation at high temperature. This paper reports on preliminary experimental results achieved with ammonia at parts-per-million concentration in nitrogen to demonstrate the feasibility of the proposed solution. Prospectively, the proposed TFEPAS solution appears particularly suited for hyphenation to micro-Gas Chromatography and for the analysis of complex solid and liquid traces samples, including compounds with low volatility such as illicit drugs, explosives, and persistent chemical warfare agents.

Introduction: It is necessary to know the sources, substances and the extension of a contaminated region. Among the main causes of air pollution is combustion, it is not enough to know a focus emission; it is necessary to determine the immission. Objective: To determine a technological alternative to reduce the negative impact of sulfur dioxide and nitrogen monoxide in "Desembarco del Granma" textile factory. Materials and Methods: The GASBOARD-3800P equipment was used to measure SO2, NO, CO, CO2 and O2. Dispersion models were made. Results and Discussion: It was determined that SO2 reach maximum values of 200 µg/m3 and NOx of 70 µg/m3 for a poor air quality category. SO2 has the highest incidence due to pollutants emitted flow and sulfur percentage in fuel oil. Conclusions: Experimentally measured values of NOx emissions from the steam generator and oil heater exceed what is allowed for existing installations. SO2 and NOx immissions exceed the accepted values. To reduce the SO2 and NOx gases impact, it is proposed to add an automatic air/fuel ratio control system to steam generator and oil heater. Io raise chimney height three meters in oil heater is proposed too. The investment required to improve the air quality of the textile company and its surroundings is $ 7759.31. [ABSTRACT FROM AUTHOR]

Abstract The present study aims in developing an alternative energy solution for compression ignition engine with mixed bio oils from Jatropha and Pongamia (Karanja) vegetable. The high viscosity of the oil was reduced by preheating and transesterification process. The properties of the oil namely viscosity, density, calorific value and flash point were evaluated. The exhaust emissions of a single cylinder diesel engine were examined using 3 hole (3H) and 4 hole (4H) nozzle with 80:20 diesel and biodiesel ratio. The 3H nozzle exhibits the optimum emission levels as per the Indian norms. At no load condition, both 3H and 4H have the emission with same NOX composition while 4H produces more CO2 and least CO and HC. As the load increases the NOX gases emission increases wherein 4H produces more NOX gas than 3H nozzle. CO gas stabilized to 0.01% from the load of 2 kg itself for 4H whilst the 3H nozzle stabilized on 8 kg.

The detection and measurement of hydrocarbons are of high interest for a variety of applications, for example within the oil and gas industry from extraction throughout the complete refining process, as well as for environmental monitoring and for portable safety devices. This paper presents a highly sensitive, selective, and robust tunable laser analyzer that has the capability to analyze several components in a gas sample stream. More specifically, a multi-gas system for simultaneous detection of C1 to iC5 hydrocarbons, using a room temperature distributed feedback interband cascade laser array, emitting in the 3.3 µm band has been realized. It combines all the advantages of the tunable laser spectroscopy method for a fast, sensitive, and selective in-line multicomponent tunable laser analyzer. Capable of continuous and milliseconds fast monitoring of C1-iC5 hydrocarbon compositions in a process stream, the analyzer requires no consumables (e.g., purging, carrier gas) and no in-field calibration, enabling a low cost of ownership for the analyzer. The system was built based on an industrial GasEye series platform and deployed for the first time in field at Preem refinery in Lysekil, Sweden, in autumn 2018. Results of the measurement campaign and comparison with gas chromatography instrumentation are presented. [ABSTRACT FROM AUTHOR]

The results of developing a new type of the gas-analytical device for detection of hard-volatile active organic compounds such as drugs, psychotropic preparations and their metabolites, environmental contaminants have been presented. It is based on the principle of thermodesorption in combination with surface ionization of analyte molecules. The trace amounts of an analyte (beginning with 0.1 ng) in sample extracts have been identified by comparing the thermodesorption spectra and their amounts have been defined according to the calibration curves of the reference samples available in the spectrometer electronic database. [ABSTRACT FROM AUTHOR]

Energy production by methanization or gasification of biomass is dependant on the chemical composition of the gas generated. The resistive sensors based on semiconductor metal oxides, like the MQ series sensors, are inexpensive and frequently used in gas detection. These sensors, initially dedicated to detecting gas leaks in safety systems, have relatively small measurement ranges (i.e. limited to concentrations below 10,000 ppm). It is therefore necessary to find solutions to adapt these categories of sensors for gas measurements in the energy sector where the gas concentration is much more significant. In this article, we propose a protocol using an adaptable capsule for MQ-4 and MQ-8 sensors to measure high concentrations of CH4 and H2 respectively. The technique consists of diluting the gas to be studied in a known volume of air. Three methods are proposed and compared regarding the linearity and the repeatability of the measurements. The first method was done in an airtight enclosed chamber, the second method consists of directly injecting the gas on the sensor placed in an open environment, and the final method was accomplished by direct injection of the gas on the sensor placed in a partially closed capsule. Comparisons show that the first technique provides the best repeatability, with a maximum standard deviation of 13.88% for CH4 measurement and 5.1% for H2. However, its linearity is weak (i.e. R2 = 0.8637 for CH4 and R2 = 0.5756 for H2). The second technique has better linearity but bad repeatability. The third technique presents the best results with R2 values of 0.9973 for the CH4 measurement and 0.9472 for H2. The use of the partially closed capsule resulted in an acceptable linear response of the sensors by up to 20% concentration of CH4 and until 13.33% concentration of H2 in the studied gas. The use of this simple and low-cost technique facilitates the characterization of combustible gases in isolated areas. It allows local operators of biomass valorization systems to control and improve their installations while avoiding the high costs of conventional measurement devices. This study, hence, contributes to the development of rural electrification projects in remote areas.

Recently, the development of modern equipment and early detection of ignition sources has become relevant due to many fires and the material and human damage caused by them. This study aimed to develop a method of searching for the ignition source by moving a mobile gas analyzer towards increasing the concentration of carbon monoxide (CO) emitted in the initial stages of fire. According to the simplex and Kiefer method, an algorithm based on the spatial detection method and guaranteed trajectory definition was used to move the mobile gas analyzer towards increasing concentration. The dependence of the engine speed on the supply voltage, the angular speed of the engine with the supply voltage, the tractive force at the wing flap frequency, the supply voltage as well as the energy consumed by the engine during propulsion were calculated. To determine the direction of the azimuth towards the movement of increasing the concentration of CO, an equation was obtained that made it possible to determine the concentration of CO as a function of the distance from the carbon monoxide source. A diagram of the gradient dependence on the distance to the ignition point was plotted, and the number of points on the trajectory on which the CO concentration is measured was determined. One way to further improve early fire detection methods is to use mobile gas analyzers in the ignition source movement and determine their coordinates with the increase in CO concentration. However, further development is restricted due to insufficient research on design methods for mobile gas analyzers, communication analysis between subsystems, and calculation methods based on mathematical models that adequately describe the basic modes of movement of mobile gas analyzers. [ABSTRACT FROM AUTHOR]

Measurement of carbon dioxide (CO2), oxygen (O2), and nitrogen (N2) concentration in modified atmosphere packaging (MAP) food is critical to be carried out by the food industry. A slight variation in concentrations of CO2, O2, and N2 in food packaging may have a significant impact on product quality and safety for human health. Accurate and reliable measurement of CO2, O2, and N2 concentrations in food packaging is crucial, and it can only be achieved by calibrating the gas analyzer. This study aimed to develop gas mixtures for the calibration of CO2, O2, and N2 gas analyzers at a typical concentration range of modified atmosphere packaging. The calibration gas mixtures were prepared gravimetrically by following ISO 6142. The concentration ranges of CO2, O2, and N2 for calibration gas mixtures were set at 9-19% mol/mol, 1-5% mol/mol, and 74-88%mol/mol, respectively. Each parent gas was identified for its impurities using gas chromatography with a pulsed discharge helium ionization detector (GC-PDHID). The compositions of CO2, O2, and N2 in the mixtures were verified by evaluating the internal consistency within the prepared gas mixtures using gas chromatography with a thermal conductivity detector (GC-TCD). The short term stability of the prepared gas mixtures was evaluated using an equal division method. The result showed that good internal consistency was achieved between the gravimetrical and GC’s verification values, having linear regression coefficient (R2) ≥ 0.999. The t-test result has shown that CO2 has better short term stability than O2 and N2. In conclusion, the developed calibration gas mixtures at a typical concentration range of modified atmosphere packaging have shown satisfying results for CO2 component. However, further evaluation is still required to minimize the instability of O2 and N2 components. [ABSTRACT FROM AUTHOR]

Soil emissions account for the second largest flux of carbon dioxide (CO2) from the Earth’s surface to the atmosphere. This flux depends on the soil organisms and the plants roots and is based on soil temperature, soil moisture and texture. The aim of the present study was to design a method to quantify CO2 emissions and to validate it using a regression model that helps develop an improved experimental model for the use of a flux measurement chamber. Soil emissions were measured in an area covered with Cynodon dactylon (L.) Pers. (Bermuda) with a closed LICOR LI-8100A dynamic chamber equipped with an infrared gas analyzer. Soil temperature and moisture were also determined using built-in sensors, in four different daytime intervals between sample collections. The intervals were studied to find the best estimation of CO2 emissions, under different environmental conditions and two observation times: the first one lasted 240 s every 5 min, for 8 h; the second one lasted 90 s with two repetitions every 30, 60 and 120 min for 12 h. The main results showed that there were significant differences in samples evaluated at 8:00 and 18:00; at other times, soil respiration was relatively homogenous. The ideal measurement interval that describes the spatial fluctuation of CO2 throughout the day and between different periods of solar radiation was 120 min. The validation of the linear regression model determined 50% of the variation, and the rest could be explained with other variables such as grass development and soil physiochemical properties. The model presented an error of ±2 mmol m-2 s-1, and it is worth mentioning that it was performed under soil moisture conditions between 0.42 and 0.53 m³ m-3 and a soil temperature between 17.6 and 30 °C. [ABSTRACT FROM AUTHOR]

An optical scheme of an optical absorption gas analyzer optimized for measuring the freon content has been presented. A radiation source with a given maximum spectral density of energy luminosity in the range from 8 to 10 μm with a reference channel of 9.5 μm and a measurement threshold of 1 ppm has been developed and studied. The design of the interference filter system has been developed. [ABSTRACT FROM AUTHOR]

Background: To our knowledge, no study has assessed the correlation of fraction of inspired oxygen (FiO2) and end-tidal oxygen (EtO2) values obtained from a gas analyzer during the preoxygenation period of rapid sequence intubation (RSI) to predict partial pressure of oxygen (PaO2) among patients requiring intubation in the emergency department (ED).Objective: The purpose of this study was to determine whether a simple equation using EtO2 and FiO2 at time of induction could reliably estimate minimal PaO2 in ED patients undergoing RSI.Methods: We conducted an observational pilot study performed in an adult ED utilizing a gas analyzer to obtain EtO2 and FiO2 values in ED patients undergoing RSI from data collectors blinded to our objective. The Pearson correlation coefficient was calculated between the equation's predicted PaO2 and the PaO2 drawn from an arterial blood gas shortly after intubation. A Bland-Altman plot analysis was performed to identify any additional bias.Results: Seventy-five patients were enrolled. The equation's mean predicted minimal PaO2 and mean PaO2 from an arterial blood gas within 3 min after intubation was 178 mm Hg (95% confidence interval [CI] 145-211 mm Hg) and 209 mm Hg (95% CI 170-258 mm Hg), respectively. The Pearson correlation coefficient between the predicted minimal PaO2 and post-intubation PaO2 demonstrated a strong correlation (r2 = 0.89). The Bland-Altman plot indicated no bias affecting the correlation between the predicted and actual PaO2.Conclusions: Among ED patients undergoing RSI, the use of a gas analyzer to measure EtO2 and FiO2 can provide a reliable measure of the minimal PaO2 at the time of induction during the RSI phase of preoxygenation. [ABSTRACT FROM AUTHOR]