A FURTHER PROGRESS REPORT ON THE STUDY OF GASES IN ENAMELING IRON*

Putting the brakes on anesthetic breakdown.

Abstract. The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley–Atmospheric Brown Clouds) international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2), along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban) ∼ 25 km (aerial distance) to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4), carbon dioxide (CO2), water vapor, and carbon monoxide (CO) were measured with a cavity ring-down spectrometer (G2401; Picarro, USA) along with meteorological parameters for 1 year (March 2013–March 2014). These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (±6.0) ppm and 2.192 (±0.066) ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 ± 2.0 ppm, CH4: 1.831 ± 0.110 ppm) and Waliguan, China (CO2: 397.7 ± 3.6 ppm, CH4: 1.879 ± 0.009 ppm) during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India). They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (±0.230) ppm in the pre-monsoon season, 2.199 (±0.241) ppm in the monsoon, 2.210 (±0.200) ppm in the post-monsoon, and 2.214 (±0.209) ppm in the winter season. The average CO2 mixing ratios were 426.2 (±25.5) ppm in the pre-monsoon, 413.5 (±24.2) ppm in the monsoon, 417.3 (±23.1) ppm in the post-monsoon, and 421.9 (±20.3) ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6 % higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1 % higher during the pre-monsoon period (seasonal maximum) than during the monsoon (seasonal minimum). On the other hand, the CO mixing ratio at Bode was 191 % higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO∕CO2 ratios of different emission sources in Nepal and India were compared with the observed CO∕CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July–3 October 2015) revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64 % higher in Bode than Chanban. The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO) showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00), a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations. These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.

Methane hydrate exists in huge amounts in certain locations, in sea sediments and the geological structures below them, at low temperature and high pressure. Production methods are in development to produce the methane to a floating platform. There it can be reformed to produce hydrogen and carbon dioxide, in an endothermic process. Some of the methane can be burned to provide heat energy to develop all needed power on the platform and to support the reforming process. After separation, the hydrogen is the valuable and transportable product. All carbon dioxide produced on the platform can be separated from other gases and then sequestered in the sea as carbon dioxide hydrate. In this way, hydrogen is made available without the release of carbon dioxide to the atmosphere, and the hydrogen could be an enabling step toward a world hydrogen economy.

Decarburizing phenomena resulted from the reaction of various gases with carburized thoriated tungsten filaments were studied by the mass spectrometric method.Analysis of the data when the filament was heated at 2000°K or at room temperature leads the following results ;(1) Carbon monoxide was easily formed by the reaction between oxygen and tungsten carbide on the surface of the filament.(2) Methane, carbon monoxide, carbon dioxide and water vapour were formed when hydrogen was introduced.(3) Forming rate of methane was proportional to the throughput of hydrogen, while those of carbon dioxide, carbon monoxide and water vapour were proportional to the square root of the throughput.The mechanism of formation of methane is supposed to be a direct reaction of hydrogen with tungsten carbide on the surface. Water vapour seems to be formed by two processes. First, hydrogen molecules dissociate to atoms on the hot filament (H2-2H). Secondly, the atoms react with oxide (glass surface) to form water vapour. Carbon monoxide and carbon dioxide are probably formed by the surface reaction between tungsten carbide and the water vapour.From these results, it is considered that the carburized thoriated tungsten filament used in an electron tube is decarburized by oxygen or hydrogen evolved from various electrodes and inner surface of the envelope.

Observations of water vapour and carbon monoxide in the Martian atmosphere with the SWC of PFS/MEX

Pinholes in aluminium alloy castings are due to gas, mainly hydrogen, liberated during solidification of the molten metal, and it remains in the metal as small bubbles. The origin of hydrogen in aluminium was shown by many authors to be ascribed to the decomposition of water vapour by the melt. How hydrogen originating from water vapour is absorbed by the melt, forms the subject of the present report, the results obtained being summarised as follows: - (1) Oxide film on the surface of the molten metal forms a remarkable protective barrier against water vapour. Owing to this protective action of the oxide coating, pinholes seldom occur even when steam is blown against the surface of the melt. The moisture in the atomosphere, therefore, seems to have almost no effect upon the melt, provided that it is coated with oxide film. On the other hand, direct contact with steam by removing the oxide film from the melt results in the formation of numerous pinholes. (2) That pinholes in aluminium alloys castings are mainly due to water vapour from the sand mould has been experimentally proved. Thus, when the oxide coating is removed in casting the metal into the mould, the most favourable condition for the absorption of hydrogen is established. (3) Hydrogen originating from water vapour seems to be in nascent state and has been found to be absorbed with great rapidity, … within 10 seconds. Prolonged contact of water vapour with the molten metal, however, does not appreciably increase the gas content in the metal. (4) Gases other than water vapour, namely, hydrogen, acetylene, carbon monoxide, and carbon dioxide were blown into the melt to examine their degree of pinhole formation. It has been found that hydrogen at a temperature below 800° is feeble, above this temperature its action gradually becomes vigorous; the action of acetylene resembles that of hydrogen, while carbon monoxide and carbon dioxide are almost inactive in creating pinholes. As the results of the above-mentioned tests, water vapour has been found, to be far more effective than the other gases in creating pinholes. (5) Gas absorbed by the melt can easily be removed by remelting, by treating with dry fluxes, or by maintaining the melt at a suitable temperature for approximately 20 minutes.

The study presents a mathematical model to analyze the dynamic evolution of molar concentrations for toluene (C7H8), water vapor (H2O) carbon monoxide (CO), hydrogen (H2), methane (CH4) and carbon dioxide (CO2) in fixed bed catalytic reactor. The mathematical model was discretized using the method of lines (MDLs) to transform the system of partial differential equations (PDEs) in a system of ordinary differential equations (ODE). The system of ODEs has been solved by the implementation of the RungeKutta Gill to estimate the chemical species C7H8, H2, CO, H2, CH4 and CO2.The estimation allows the quantification of individual forecasts of the variables presented in this study. However, valuable information can be obtained from the estimated behaviors in fixed bed catalytic reactor. The model has allowed the validation of chemical species (H2, CO and CO2) by comparing the optimized values. Additionally, the concentrations for the chemical species C7H8, H2, CO, H2, CH4 and CO2 was studied.

Fengyun-3E (FY-3E)/Hyperspectral Infrared Atmospheric Sounder-II (HIRAS-II) is an extension Fengyun-3D (FY-3D)/HIRAS-I. It is crucial to fully explore and analyze the detection capabilities of these two instruments for atmospheric gas composition. Based on the observed spectral data from the infrared hyperspectral detection instruments FY-3D/HIRAS-I and FY-3E/HIRAS-II, simulated radiance data and Jacobian matrices are obtained using the Rapid Radiative Transfer Model RTTOV (Radiative Transfer for TOVS (TIROS Operational Vertical Sounder)). By perturbing temperature (T), surface temperature (Tsurf), water vapor (H2O), ozone (O3), carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and nitrous oxide (N2O), the brightness temperature differences before and after the perturbations are calculated to analyze the sensitivity of temperature and various atmospheric gas components. The Improved Optimal Sensitivity Profile (OSP) algorithm is used to select the channels for atmospheric gas retrieval. The observation error covariance and background error covariance matrices are calculated, and then the information capacity is calculated, specifically the degrees of freedom for signal(DFS) and the entropy reduction (ER). Based on this, a comparative analysis is conducted on the information capacity of atmospheric water vapor and ozone components contained in the hyperspectral detection data from HIRAS-I and HIRAS-II instruments, respectively, to explore the retrieval capabilities of the two instruments for atmospheric gas components. We selected clear-sky data from the African oceanic region and the Chinese Yangtze River Delta terrestrial region for quantitative analysis of the information capacity of HIRAS-I and HIRAS-II. The results show that FY-3D/HIRAS-I and FY-3E/HIRAS-II exhibit different sensitivities to atmospheric gas components. In different experimental regions, temperature and water vapor show the most dramatic sensitivity changes, followed by ozone, methane, and nitrous oxide, while carbon monoxide and carbon dioxide exhibit the lowest variability. Regarding channel selection, HIRAS-II identifies more gas channels compared to HIRAS-I. The experiments concluded that HIRAS-II has a significantly higher information capacity than HIRAS-I, and the information capacity of atmospheric gas components varies across different experimental regions. Water vapor and ozone exhibit the highest information capacity, followed by nitrous oxide and methane, while carbon monoxide and carbon dioxide demonstrate the lowest capacity. The H2O ER (DFS) contained in FY-3E/HIRAS-II is 1.51 (0.35) higher than that in FY-3D/HIRAS-I, the O3 ER (DFS) in FY-3E/HIRAS-II is 1.51 (0.36) higher than that in FY-3D/HIRAS-I, while the N2O ER (DFS) in FY-3E/HIRAS-II is 0.17 (0.19) higher and the CH4 ER (DFS) is 0.07 (0.04) higher than that in FY-3D/HIRAS-I.

Formation of carbon oxides during tobacco combustion: Pyrolysis studies in the presence of isotopic gases to elucidate reaction sequence

Capturing rogue carbon

Investigation of electrochemical carbon monoxide sensor monitoring of anesthetic gas mixtures.

The atmospheric emitted radiance interferometer (AERI) is a ground-based instrument that measures the downwelling infrared radiance from the Earth’s atmosphere. The observations have broad spectral content and sufficient spectral resolution to discriminate among gaseous emitters (e.g., carbon dioxide and water vapor) and suspended matter (e.g., aerosols, water droplets, and ice crystals). These upward-looking surface observations can be used to obtain vertical profiles of tropospheric temperature and water vapor, as well as measurements of trace gases (e.g., ozone, carbon monoxide, and methane) and downwelling infrared spectral signatures of clouds and aerosols.The AERI is a passive remote sounding instrument, employing a Fourier transform spectrometer operating in the spectral range 3.3–19.2 μm (520–3020 cm-1) at an unapodized resolution of 0.5 cm-1 (max optical path difference of 1 cm). The extended-range AERI (ER-AERI) deployed in dry climates, like in Alaska, have a spectral range of 3.3–25.0 μm (400–3020 cm-1) that allow measurements in the far-infrared region. Typically, the AERI averages views of the sky over a 16-second interval and operates continuously.

Cause-and-effect analysis of the photochemical interactions among CH 4 CO, O 3 and OH in the global troposphere

A series of ice mixtures containing carbon monoxide (CO), carbon dioxide (CO(2)), and molecular oxygen (O(2)) with varying carbon-to-oxygen ratios from 1 : 1.5 to 1 : 4 were irradiated at 10 K with energetic electrons to derive formation mechanisms and destruction pathways of carbon monoxide (CO), carbon dioxide (CO(2)), and carbon trioxide (CO(3)) in extraterrestrial, low temperature ices. Reactants and products were analyzed on line and in situ via absorption-reflection-absorption FTIR spectroscopy in the solid state, while the gas phase was sampled by a quadrupole mass spectrometer (QMS). Additionally, isotopically mixed ices consisting of (i) (13)CO ratio C(18)O ratio CO(2), (ii) CO(2)ratio C(18)O(2), and (iii) CO(2)ratio(18)O(2) were irradiated in order to derive mechanistical and kinetic information on the production and destruction pathways of the following species: (i) (13)CO, C(18)O, CO(2), CO, (13)CO(2), (18)OCO, and (13)CO(3) (C(2v)), (ii) CO(2), C(18)O(2), CO, C(18)O, (18)OCO, CO(3) (C(2v)), OC(18)OO (C(2v)), OC(18)O(2) (C(2v)), (18)OCO(2) (C(2v)), (18)OC(18)OO (C(2v)), and C(18)O(3) (C(2v)), and (iii) CO(2), CO, (18)OCO, C(18)O, and C(18)O(2).

ABSTRACTUse of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen in “tight” energy-efficient homes in the United States. A total of 20,000 simulations were conducted for each Department of Energy (DOE) heating region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U.S. Environmental Protection Agency (EPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO2 were below the U.S. Consumer Product Safety Commission (CPSC) guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases and were below the World Health Organization (WHO) standard of 0.11 ppm in 99–100% of all cases. Predicted levels of CO2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the EPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer’s instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in this report.Implications: Probabilistic modeling of indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen associated with use of vent-free gas heating appliances provides new data indicating that uses of these devices are consistent with acceptable indoor air quality in “tight” energy-efficient homes in the United States. This study will provide authoritative bodies such as the International Code Council with definitive information that will assist in the development of future versions of national building codes, and will provide evaluation of the performance of unvented gas heating products in energy conservation homes.