Spectroscopic analysis of multicomponent gas mixtures with wide range carbon monoxide laser

2010 ◽  
Author(s):  
E. Yu. Bondarchuk ◽  
A. A. Ionin ◽  
A. Yu. Kozlov ◽  
Yu. M. Klimachev ◽  
A. A. Kotkov ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Spectroscopic Analysis ◽  
Gas Mixtures ◽  
Wide Range ◽  
Multicomponent Gas

OPTIMIZATION OF GAS-DIESEL ENGINE REGULATION AS A METHOD OF IMPROVING ITS ECOLOGICAL CHARACTERISTICS

2021 ◽  
pp. 28-32
Author(s):  
VALERIY L. CHUMAKOV ◽  
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Hydrocarbon Fuel ◽  
Load Range ◽  
Engine Operation ◽  
Exhaust Gases ◽  
Wide Range ◽  
Diesel Cycle

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.

scholarly journals The Role of Host-Generated H2S in Microbial Pathogenesis: New Perspectives on Tuberculosis

2020 ◽  
Vol 10 ◽  
Author(s):  
Md. Aejazur Rahman ◽  
Joel N. Glasgow ◽  
Sajid Nadeem ◽  
Vineel P. Reddy ◽  
Ritesh R. Sevalkar ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Hydrogen Sulfide ◽  
Host Immunity ◽  
Microbial Pathogens ◽  
Microbial Pathogenesis ◽  
Enzymatic Production ◽  
Growth And Survival ◽  
Wide Range

For centuries, hydrogen sulfide (H2S) was considered primarily as a poisonous gas and environmental hazard. However, with the discovery of prokaryotic and eukaryotic enzymes for H2S production, breakdown, and utilization, H2S has emerged as an important signaling molecule in a wide range of physiological and pathological processes. Hence, H2S is considered a gasotransmitter along with nitric oxide (•NO) and carbon monoxide (CO). Surprisingly, despite having overlapping functions with •NO and CO, the role of host H2S in microbial pathogenesis is understudied and represents a gap in our knowledge. Given the numerous reports that followed the discovery of •NO and CO and their respective roles in microbial pathogenesis, we anticipate a rapid increase in studies that further define the importance of H2S in microbial pathogenesis, which may lead to new virulence paradigms. Therefore, this review provides an overview of sulfide chemistry, enzymatic production of H2S, and the importance of H2S in metabolism and immunity in response to microbial pathogens. We then describe our current understanding of the role of host-derived H2S in tuberculosis (TB) disease, including its influences on host immunity and bioenergetics, and on Mycobacterium tuberculosis (Mtb) growth and survival. Finally, this review discusses the utility of H2S-donor compounds, inhibitors of H2S-producing enzymes, and their potential clinical significance.

scholarly journals Isotherms of hydrogen, carbon monoxide and their mixtures

1931 ◽  
Vol 134 (824) ◽  
pp. 502-512 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Pressure Range ◽  
Close Agreement ◽  
Gas Mixtures ◽  
Industrial Processes ◽  
Gaseous Mixtures ◽  
Previous Communication ◽  
New Apparatus ◽  
Temperature Ranges

In a previous communication from these laboratories by G. A. Scott an account was given of the determination of the isotherms of hydrogen, carbon monoxide and mixtures of the two in the molecular proportion 2 : 1, 1 : 1 and 1 : 2 over a pressure range up to 170 atmospheres and at a temperature of 25° C. Since the completion of that investigation new apparatus has been installed so that the pressure and temperature ranges might be extended; and in this paper are embodied the results of further determinations carried out at both 0° C. and 25° C. and over a pressure range extending up to 600 atmospheres. In pursuing this investigation further it is our endeavour to furnish information in regard to the gaseous mixtures in question over the pressure and temperature ranges now commonly used in industrial processes. The Isotherms of the Single Gases . A repetition in our new apparatus of the determinations previously made by Scott both for the single gases and gas mixtures at 25° C. and at pressures up to 170 atmospheres showed his figures to be in close agreement with our own, the variations never exceeding 0·1 per cent.

scholarly journals Climatology and long-term evolution of ozone and carbon monoxide in the UTLS at northern mid-latitudes, as seen by IAGOS from 1995 to 2013

2017 ◽  
Author(s):  
Yann Cohen ◽  
Hervé Petetin ◽  
Valérie Thouret ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Lower Stratosphere ◽  
Boreal Summer ◽  
Brazilian Coast ◽  
Seasonal Cycles ◽  
Western Coast ◽  
Data Set ◽  
Upper Troposphere ◽  
North East ◽  
Wide Range

Abstract. In situ measurements in the upper troposphere – lower stratosphere (UTLS) are performed in the framework of the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System) for ozone since 1994 and for carbon monoxide since 2002. The flight tracks cover a wide range of longitudes in the northern extratropics, extending from the North American western coast (125° W) to the eastern Asian coast (135° E), and more recently over the northern Pacific ocean. Different tropical regions are also sampled frequently, such as the Brazilian coast, central and southern Africa, southeastern Asia and the western Maritime Continent. As a result, a new set of climatologies for O3 (Aug. 1994–Dec. 2013) and CO (Dec. 2001–Dec. 2013) in the upper troposphere (UT), tropopause layer and lower stratosphere (LS) are made available, including quasi-global gridded horizontal distributions, and seasonal cycles over eight well sampled regions of interest in the northern extratropics. The seasonal cycles generally show a summertime maximum in O3 and a springtime maximum in CO in the UT, in contrast with the systematic springtime maximum in O3 and the quasi-absence of seasonal cycle of CO in the LS. This study highlights some regional variabilities in the UT notably (i) a west-east difference of O3 in boreal summer with up to 15 ppb more O3 over central Russia compared with northeast America, (ii) a systematic west-east gradient of CO from 60° E to 140° E (especially noticeable in spring and summer with about 5 ppb by 10 degrees longitude), (iii) a broad spring/summer maximum of CO over North East Asia, and (iv) a spring maximum of O3 over Western North America. Thanks to almost 20 years of O3 and 12 years of CO measurements, the IAGOS database is a unique data set to derive trends in the UTLS. Trends in O3 in the UT are positive and statistically significant in most regions, ranging from +0.25 to +0.45 ppb yr−1, characterized by the significant increase of the lowest values of the distribution. No significant trends of O3 are detected in the LS. Trends of CO in the UT, tropopause and LS are all negative and statistically significant. The estimated slopes range from −1.37 to −0.59 ppb yr−1 , with a nearly homogeneous decrease of the lowest values of the monthly distribution (fifth percentile) contrasting with the high inter-regional variability of the highest values (95th percentile).

Prediction of CO and NOx Pollutants in a Stratified Bluff Body Burner

2017 ◽  
Author(s):  
Pascal Gruhlke ◽  
Fabian Proch ◽  
Andreas M. Kempf ◽  
Enric Illana Mahiques ◽  
Stefan Dederichs ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Bluff Body ◽  
Combustion Products ◽  
Combustion Model ◽  
Wide Range ◽  
Flame Region ◽  
Numerical Grid ◽  
Nitric Oxide Emissions ◽  
Heavy Duty Gas Turbine

The major exhaust gas pollutants from heavy duty gas turbine engines are CO and NOx. The difficulty of predicting the concentration of these combustion products originates from their wide range of chemical time scales. In this paper, a combustion model that includes the prediction of the carbon monoxide and nitric oxide emissions is tested. Large eddy simulations (LES) are performed using a compressible code (OpenFOAM). A modified flamelet generated manifolds (FGM) approach is applied with a thickened flame approach (ATF) to resolve the flame on the numerical grid, with a flame sensor to ensure that the flame is only thickened in the flame region. For the prediction of the CO and NOx emissions, pollutant species transport equations and a second, CO based, progress variable are introduced for the flame burnout zone to account for slow chemistry effects. For the validation of the models, the Cambridge burner of Sweeney and Hochgreb [1, 2] is employed, as both carbon monoxide and nitric oxide [3] data is available.

scholarly journals Экспериментальная установка на базе перестраиваемого в диапазоне волн 5.3-12.8 μm квантово-каскадного лазера для спектрального анализа выдыхаемого человеком воздуха

2021 ◽  
Vol 129 (6) ◽  
pp. 747
Author(s):  
А.В. Щербакова ◽  
Д.Р. Анфимов ◽  
И.Л. Фуфурин ◽  
И.С. Голяк ◽  
И.А. Трапезникова ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Peak Power ◽  
Gas Mixtures ◽  
Sensitivity Threshold ◽  
Gas Cell ◽  
Single Spectrum ◽  
Quantum Cascade ◽  
Exhaled Air ◽  
Multicomponent Gas ◽  
Ppm Level

An experimental setup and a method for analyzing multicomponent gas mixtures, including human exhaled air, are presented. The installation consists of a quantum cascade laser, tunable in the wavelength range of 5.3-12.8 µm, with a peak power of 150 mW, and a multi-pass Herriot gas cell, which allows obtaining an optical path of up to 76 m. The registration time of a single spectrum is about 50 ms. For acetone and ethanol, which are potential biomarkers of some human diseases, the sensitivity threshold at the sub-ppm level was experimentally determined. A system of sample preparation and pre-drying is proposed, which allows analyzing both multicomponent gas mixtures and the air exhaled by a person. The variants of application of the described installation in biomedical applications are proposed.

scholarly journals Molecular Simulations of CO2/CH4, CO2/N2 and N2/CH4 Binary Mixed Hydrates

2021 ◽  
Vol 83 (3) ◽  
pp. 372-378
Author(s):  
A. A. Sizova ◽  
S. A. Grintsevich ◽  
M. A. Kochurin ◽  
V. V. Sizov ◽  
E. N. Brodskaya
Keyword(s):  
Carbon Dioxide ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Gas Hydrates ◽  
Molecular Simulations ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Grand Canonical Monte Carlo ◽  
Multicomponent Gas ◽  
Grand Canonical

Abstract Grand canonical Monte Carlo simulations were performed to study the occupancy of structure I multicomponent gas hydrates by CO2/CH4, CO2/N2, and N2/CH4 binary gas mixtures with various compositions at a temperature of 270 K and pressures up to 70 atm. The presence of nitrogen in the gas mixture allows for an increase of both the hydrate framework selectivity to CO2 and the amount of carbon dioxide encapsulated in hydrate cages, as compared to the CO2/CH4 hydrate. Despite the selectivity to CH4 molecules demonstrated by N2/CH4 hydrate, nitrogen can compete with methane if the gas mixture contains at least 70% of N2.

scholarly journals Synthesis, stability, and reactivity of mesoionic carbene iridium dihydride complexes

2020 ◽  
Author(s):  
Marta Olivares ◽  
Martin Albrecht
Keyword(s):  
Electronic Properties ◽  
Functional Groups ◽  
Pyridine Ring ◽  
Spectroscopic Analysis ◽  
Pka Values ◽  
Trans Effect ◽  
Structural Assignment ◽  
Wide Range ◽  
Hydride Metal ◽  
The Stability

Pyridyl-triazolylidene ligands with variable donor properties were used as tunable ligands at a dihydride iridium(III) center. The straightforward synthesis of this type of ligand allows for an easy incorporation of electron donating substituents in different positions of the pyridine ring or different functional groups such as esters, alkoxy or aliphatic chains on the C4 position of the triazole heterocycle. The stability of these hydride metal systems allowed these complexes to be used as models for studying the influence of the ligand modifications on hydride reactivity. Spectroscopic analysis provided unambiguous structural assignment of the dihydride system. Modulation of the electronic properties of the wingtip substituents did not appreciably alter the reactivity of the hydrides. Reactivity studies using acids with a wide range of pKa values indicated a correlation between hydride reactivity and acidity and showed exclusive reactivity towards the less shielded hydride trans to the carbene carbon rather than the more shielded hydride trans to the pyridine ring, suggesting that the trans effect is more relevant in these reactions than the NMR spectroscopically deduced hydridic character.

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