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Combined effects of ambient air pollution and home environmental factors on low birth weight
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Circulating microRNAs as putative mediators in the association between short-term exposure to ambient air pollution and cardiovascular biomarkers
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CO 2 capture from ambient air via crystallization with tetraalkylammonium hydroxides
Aqueous solutions of tetra( n -alkyl)ammonium hydroxides, [N nnnn ][OH] with n = 2: n -ethyl, 3: n -propyl, 4: n -butyl are effective in direct air carbon capture (DAC) with high CO 2 /[N nnnn ][OH] ratio.
Aging studies on chemical vapor deposition and mechanically exfoliated molybdenum disulfide flakes heated in ambient air
The structural integrity of atomically thin two-dimensional molybdenum disulfide (MoS 2 ) is crucial for high-temperature applications, including nanoelectronics and optoelectronics. This study explores the structural stability and electrical performance, under extended thermal exposure in air, of MoS 2 flakes synthesized via chemical vapor deposition (CVD) and mechanical exfoliation. The MoS 2 flakes, both CVD-grown and mechanically exfoliated, were subjected to heating at 200 °C with a relative humidity of 60(±5)% for a prolonged period and investigated with atomic force microscopy and Raman spectroscopy. This study shows that CVD-grown flakes developed noticeable cracks after prolonged heating, whereas mechanically exfoliated flakes mostly retained their structural integrity. Also, both types of flakes showed a decrease in layer thickness and lateral size over time, with mechanically exfoliated flakes exhibiting a comparatively smaller reduction in substrate coverage area. In addition, MoS 2 -based two-terminal devices were subjected to heating at 150 °C for approximately 1100 h, and their electrical characterization revealed a steady rise in current during constant voltage (5 V) conditions. This study enhances our understanding of MoS 2 stability and provides guidance for improving the reliability of MoS 2 -based devices in high-temperature electronic applications.
Tussock tundra surface temperatures, ambient air and incoming photosynthetically active radiation measured at the NGEE Arctic Council site, 2021 - 2023
This dataset contains temperature measurements carried out along two fiber optics cables/lines (150 m each) laid out along the ground at the Next Generation Ecosystem Experiment (NGEE) Arctic site near Council, Alaska. The lines traverse an heterogeneous part of the tussock tundra site including thermokarst features and lichen dominated sections of the tundra. Measurements were done using a Sensornet Oryx DTS, a Distributed Temperature sensor that was installed in September 2021 and taken down in August 2023. The sensor was powered by solar power with data being collected every 30 minutes at 1 m resolution. In addition to these measurements air temperature and incoming photosynthetically active radiation (PAR) are provided. These measurements are co-located with the NGEE Arctic Council eddy flux and meteorological station (AmeriFlux ID US-NGC). Included are six *.csv files (four data files and two reporting format files) and two *.kml files. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).
Comparative pathology of animals exposed to carbon tetrachloride in oxygen at 258 mm. hg and in ambient air.
Comparative pathology of animals continuously exposed to varied concentrations of carbon tetrachloride vapor in altitude chamber
Strain-cycling fatigue behavior of ten structural metals tested in liquid helium, liquid nitrogen, and ambient air
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A Summary of Ambient Air at John F. Kennedy Space Center with a Comparison to Data from the Florida Statewide Monitoring Network (1983-1992)
The EPA criteria air pollutants were monitored at Kennedy Space Center (KSC) since 1983 to comply the prevention of significant deterioration requirements under the Clean Air Act amendments passed by Congress in 1977 and 1990. Monitoring results show that monthly maximum 24-hour total suspended particulates decreased from 144.6 micograms/cu m in 1988 to 73.0 micrograms/cu m in 1991 and increased to 149.3 micrograms/cu m in 1992. Inhalable particulates increased from 56.1 gg/M3 in 1983 to 131.4 micrograms/cu m in 1988, and then decreased to 38.5 micrograms/cu m in 1992. Sulfur dioxide monthly maximum 24-hour average concentrations decreased each year from 135.2 micrograms/cu m in 1983 to 33.8 micrograms/cu m in 1992. Nitrogen dioxide concentrations increased from 5.1 micrograms/cu m in 1983 to 5.9 micrograms/cu m in 1988, then decreased to 4.5 micrograms/cu m in 1992. Carbon monoxide annual average concentrations decreased from 6.2 micrograms/cu m in 1983 to 1.1 micrograms/cu m in 1988, and increased to 1.2 micrograms/cu m in 1992. Ozone maximum 1-hour concentrations increased from 98 parts per billion (ppb) in 1983 to 134 ppb in 1989, and then decreased to 80 ppb in 1992. Total annual rainfall ranged from 37.47 inches to 57.47 inches and shows a 6.6 percent increase over this same ten year period.
Design and Performance of a Gas Chromatograph for Automatic Monitoring of Pollutants in Ambient Air
In recent years, interest in air pollution constituents has focused on carbon monoxide and hydrocarbons as prime components of polluted air. Instrumental methods have been developed, and commercial instruments for continuous monitoring of these components have been available for a number of years. For the measurement of carbon monoxide, non-dispersive infrared spectroscopy has been the accepted tool, in spite of its marginal sensitivity at low parts-per-million levels. For continuously monitoring total hydrocarbons, the hydrogen flame ionization analyzer has been widely accepted as the preferred method. The inadequacy of this latter method became evident when it was concluded that methane is non-reactive and cannot be considered a contaminant even though present at over 1 ppm in the earth's atmosphere. Hence, the need for measuring methane separately became apparent as a means of measuring the reactive and potentially harmful non-methane hydrocarbons fraction. A gas chromatographic method for the measurement of methane and total hydrocarbons which met these requirements has been developed. In this technique, methane was separated on conventional gas chromatographic columns and detected by a hydrogen flame ionization detector (FID) while the total hydrocarbons were obtained by introducing a second sample directly into the FID without separating the various components. The reactive, or non-methane hydrocarbons, were determined by difference. Carbon monoxide was also measured after converting to methane over a heated catalyst to render it detectable by the FID. The development of this method made it possible to perform these measurements with a sensitivity of as much as 1 ppm full scale and a minimum detectability of 20 ppb. Incorporating this technique, criteria were developed by APCO for a second generation continuous automatic instrument for atmospheric monitoring stations.
Reduced Noise Gas Turbine Engine System and Supersonic Exhaust Nozzle System Using Elector to Entrain Ambient Air
One embodiment of the present invention is a unique gas turbine engine system. Another embodiment is a unique exhaust nozzle system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engine systems and exhaust nozzle systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.
Ambient Air Monitoring of Well Pads During Drilling Activities
A&WMA’s 114th Annual Conference & Exhibition, Virtual, June 14-17, 2021
Direct measurement of the growth of small particles in ambient air using captive aerosol chambers
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Direct measurement of the growth of small particles in ambient air using captive aerosol chambers
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The Role of Scale Volatilization During Oxidation of Ni-based Alloys in Static Laboratory Air Containing Ambient Humidity
Poster presentation for the 2025 High Temperature Corrosion Gordon Research Conference summarizing a study demonstrating the importance of water vapor present in the ambient air in dictating the oxidation performance of chromia-forming alloys used in a variety of high temperature applications.
Numerical simulation of an atmospheric pressure plasma jet with coaxial shielding gas
A two-dimensional ( r, z ) numerical simulation of the discharge characteristics of an atmospheric pressure plasma jet (APPJ), with coaxial shielding gas, was performed. The helium working gas flowed in a central capillary tube, engulfing a needle electrode powered by 13.7 MHz radio frequency sinusoidal voltage. The N 2 shielding gas flowed in the annular space of a coaxial tube. These gases emerged, in laminar flow, in a 78%N 2 -21%O 2 -1%Ar dry air ambient. The characteristics of the APPJ with shielding gas were compared to those of the APPJ without shielding gas. The nitrogen shielding gas hindered the diffusion of oxygen and argon from the ambient air into the helium jet. With the shielding gas present, more nitrogen penetrated into the helium core, causing a shorter plasma ‘plume’. The flow rates of the working and shielding gas, critically affected the gas temperature, and in turn the discharge characteristics. For a He flow of 2 standard liters per minute (slm), switching on the nitrogen shielding gas flow (at 4.5 slm) reduced the on-axis O 2 and Ar mole fractions from 3.9 × 10 - 4 to 6.8 × 10 - 5 and from 1.9 × 10 - 5 to 3.3 × 10 - 6 , respectively, at an axial distance of 3 mm downstream of the nozzle. The radial profiles of the mole fractions of the ambient gases were monotonically and strongly decreasing towards the system axis, for short axial distances from the nozzle (~1 mm), but became progressively flatter at longer distances from the nozzle (3 mm and 5 mm). Simulation predictions captured the salient features of experimental data of ambient species mole fractions in the plasma jet, and the 706 nm optical emission intensity profiles of the He 3 3 S excited state.
SAIL-Isotopologue (SAIL-iso) Field Campaign Report
The SAIL-iso project took place from November 19, 2022 to June 3, 2023 as part of the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility’s Surface Atmosphere Integrated Field Laboratory (SAIL) project at the main project site in Gothic, Colorado. The project sought to use measurements of the stable isotopic composition of water vapor to better understand cloud-aerosol interactions in a remote mountainous watershed. Water vapor isotopologue and humidity measurements were determined using a Los Gatos Research Triple Water Vapor Isotope Analyzer (TWVIA). The instrument was deployed in the guest van and consists of three main components: a water vapor isotope analyzer, a Los Gatos Research Water Vapor Isotope Standard Source (WVISS), and a Los Gatos Research Dry Air Source. Ambient air samples were collected through an inlet located about one meter above roof of the shipping container. Samples were then delivered to the analyzer through Teflon tubing by use of an external pump to minimize the transport time between the inlet and analyzer. The inlet tubing was surrounded by a Briskheat heat trace and insulating material to ensure ambient air samples did not fall below the dew point and result in condensation. The analyzer uses cavity ringdown spectroscopy to report isotopic ratios of ambient air samples at a frequency of 1 Hz. The calibration unit of the instrument was used in conjunction with the dry air source to periodically measure the δ values of standard waters. It uses a nebulizer to push small water droplets into a hot chamber that vaporizes the water without fractionation. This vapor was then transported to the analyzer using a built-in compressor and the dry air source, which allows each standard with known δ values to be measured at a wide range of humidity values for post-measurement calibration of ambient air samples. Multiple sources of uncertainty are introduced at different stages during the data collection and processing. These include (1) instrument precision, (2) uncertainty in the secondary standards, (3) humidity-correction uncertainty, and (4) Vienna Standard Mean Ocean Water – Standard Light Antarctic Precipitation (VSMOW-SLAP) calibration uncertainty. Uncertainty from each step is propagated in quadrature to calculate a total uncertainty of each isotopologue. Uncertainty was determined to be 2.3‰ for δD and 0.4‰ for δ 18 O.