A continuous wave, thermoelectrically cooled, distributed feedback quantum cascade laser (DFB-QCL) based sensor platform for the quantitative detection of ammonia (NH3) concentrations present in exhaled human breath is reported. The NH3 concentration measurements are performed with a 2f wavelength modulation quartz enhanced photoacoustic spectroscopy (QEPAS) technique, which is very well suited...

Geometric and electronic properties of 3,4-ethylenedioxythiophene (EDOT), styrene sulfonate (SS), and EDOT: SS oligomers up to 10 repeating units were studied by the self-consistent charge density functional tight-binding (SCC-DFTB) method. An application of PEDOT:PSS for ammonia (NH3) detection was highlighted and investigated both experimentally and theoretically. The results showed an import...

The intercalation compounds of layered dichalcogenides MX2 (M = transition metal, X = S, Se) with Lewis base guest molecules have received considerable attention due to their interesting physical properties and structural anisotropy [1]. The most simple molecule that is known to intercalate is the thermodynamically stable compound NH3; extensive work has been devoted to the characterization of ...

The oxidation of ammonia to nitrogen by selective catalytic oxidation (NH3-SCO) over a bimetallic CuO/CeO2 nanoparticle catalyst at temperatures between 423 and 673K. A bimetallic CuO/CeO2 nanoparticle catalyst was prepared by co-precipitation method at molar ratio of 6:4. This study also considers how the concentration of influent NH3 (C0 = 800 ppm), the space velocity (GHSV = 92000/hr), the r...

Tandem mass spectrometry provides information on the dissociation pathways of gas-phase ions by providing a link between product ions and parent ions. However, there exists a distinct possibility that a parent ion does not dissociate directly to the observed product ion, but that the reaction proceeds through unobserved reaction intermediates. This work describes the discovery and kinetic analy...

As early as 1785 Claude Louis Berthollet (17481822) studied the decomposition of ammonia by electric sparking. He found that 0.725 by volume of hydrogen and 0.275 by volume of nitrogen were produced. Several other workers confirmed this effect of sparking but noted that some NH3 always remains. The partial formation of NH3 when mixtures of H2 and N2 were subjected to various forms of electrical...

Radio emission from ammonia, a suspected parent molecule in comets, was detected from comet Hale-Bopp near its perihelion passage with the 100-m Effelsberg Radio Telescope. Signals from the five lowest metastable inversion transitions of NH3 were obtained to derive a rotational temperature of 104±30 K, assumed to be representative of the kinetic temperature in the comet’s inner coma (R < 5000 k...

British chemist Humphry Davy is best known for being the first person to isolate several elements, including sodium and calcium. Davy carried out his work electrolytically more than 200 years ago as an early experimenter with batteries. Less known about Davy is that during experiments on water electrolysis, in which water is split into hydrogen and oxygen, he found that ammonia formed on the ca...

Ammonia inversion lines are often used as probes of the physical conditions in the dense ISM. The excitation temperature between the first two para metastable (rotational) levels is an excellent probe of the gas kinetic temperature. However, the calibration of this ammonia thermometer depends on the accuracy of the collisional rates with H2. Here we present new collisional rates for ortho-NH3 a...

Ammonia-based selective catalytic reduction (SCR) has become the major control strategy for NOx emissions from light and heavy duty diesel engines. Before reducing NOx on the SCR active material, ammonia storage on the active sites of the catalyst is crucial. The in operando measurement of the dielectric properties of the catalyst material using microwave cavity perturbation is a promising indi...