BN has been deposited with plasma enhanced CVD using borane dimethyl amine and NH3. The resulting layers are stable in air, although they contain an excess of boron, the actual amount depending on the deposition conditions. The presence of relatively large amounts of carbon in the layers indicates the incomplete decomposition of the organic fragment. Generally the layers posses the turbostratic...

Ammonia gas is the only significant basic gas that neutralizes atmospheric acid gases produced from combustion of fossil fuels. This reaction produces an aerosol that is a component of atmospheric haze, is implicated in nitrogen (N) deposition, and may be a potential human health hazard. Because of the potential impact of NH3 emissions, environmentally and economically, the objective of this st...

Two methods were described to estimate interference in the measurements of infrared (IR) photoacoustic multi-gas analyzer (PAMGA). One is IR spectroscopic analysis (IRSA) and the other is mathematical simulation. An Innova 1412 analyzer (AirTech Instruments, Ballerup, Denmark) with two different filter configurations was used to provide examples that demonstrate the two methods. The filter conf...

A new chemistry module that simulates atmospheric ammonia (NH3) and ammonium (NH + 4 ) was incorporated into a backward-in-time stochastic Lagrangian air quality model (STILT-Chem) that was originally developed to simulate the concentrations of a variety of gas-phase species at receptors. STILT-Chem simulates the transport of air parcels backward in time using ensembles of fictitious particles ...

The Ogawa passive sampler (Ogawa USA, Pompano Beach, Florida) is a useful tool for monitoring atmospheric ammonia (NH3(g)) concentrations and assessing the effects of agricultural waste management practices on NH3(g) emissions. The Ogawa sampler, with filter-discs impregnated with citric acid, was used to trap and determine NH3(g) concentrations in a variety of agricultural settings. A wide ran...

Does an OH-flipping barrier hinder H-bond formation between a gas phase molecule and a water monolayer whose free OH ligands point toward a substrate? According to density functional theory calculations for water on Pt(111) the answer is yes, when the molecule is CO or N2, but no when it is NH3. The difference is the relatively strong attraction of the NH3 lone pair to free OH ligands.

The adsorption of common gas molecules (N2, CO, CO2, H2O, NH3, NO, NO2, and O2) on germanene is studied with density functional theory. The results show that N2, CO, CO2, and H2O are physisorbed on germanene via van der Waals interactions, while NH3, NO, NO2, and O2 are chemisorbed on germanene via strong covalent (Ge-N or Ge-O) bonds. The chemisorption of gas molecules on germanene opens a ban...

Since the Euro-III standard was adopted, the main methods to inhibit NOx production in diesel engines are exhaust gas recirculation (EGR) and select catalyst reduction (SCR). On these methods SCR offers great fuel economy, so it has received wide attention. However, there also exists a trade-off law between NOx conversion efficiency and NH3 slip under dynamic conditions. To inhibit NH3 slip wit...

We present the results of the observations of the (J, K) = (1, 1) and the (J, K) = (2, 2) inversion transitions of the NH3 molecule toward a large sample of 40 regions with molecular or optical outflows, using the 37 m radio telescope of the Haystack Observatory. We detected NH3 emission in 27 of the observed regions, which we mapped in 25 of them. Additionally, we searched for the 616−523 H2O ...

Gas analyzers are commonly protected from impurities in air sampling via use of in-line filters to ensure operational performance and longevity of the instruments. This is especially true for extended period of air monitoring under conditions where airborne dust exists. Prices for commercially available filters vary substantially. A question that has often come up but has not received much inve...