Oscillating microbalance

The tapered-element oscillating microbalance (TEOM) sensor, as described by Patashnick and Rupprecht, consists of an oscillating tapered tube with a filter at its free end (Fig. 13.40). The mass of the filter increases due to the collected aerosol and produces a shift in the oscillation frequency of the tapered tube that is directly related to mass. 

Patashnick, H. and F..G. Rupprecht. Conrinuoiis PMm Measurements Using Tapered Element Oscillating Microbalance. /. Air Waste Manage. Assoc. 41 (1991), pp. 1079-1083. 

The total mass of particles per unit volume of air is one of the major parameters used to characterize particles in air and, along with size, is the basis of air quality standards for particulate matter (see Chapter 2). Methods of mass measurement include gravimetric methods, /3-ray attenuation, piezoelectric devices, and the oscillating microbalance. 

The most often measured property of the LRT wildfire smokes is the mass concentration of aerosol particles in fine (PM2.5) or submicron (PMi) or in fine and coarse size fraction together (PM10). The mass concentration is usually determined either with a tapered element oscillating microbalance (e.g., [19]), or with the instruments based on p-attenuation (e.g., [13]). In addition to mass concentration, real-time instruments can measure other physical properties of particles, e.g., number concentration of particles in different size fractions using a differential mobility particle sizer [13] or the optical characteristics of smoke by a nephelometer [32]. Ground-based instruments also include remote sensing instruments such as sun photometers [32],... 

In-Situ Study of Carbon Deposition during C02 Reforming of Methane for Synthesis Gas Production, Using the Tapered Element Oscillation Microbalance... 

For the studies described in this chapter, a novel system was employed, namely the tapered element oscillation microbalance (TEOM), to monitor the dynamic process of carbon formation under real C02 reforming conditions. The use of TEOM enables carbon formation to be measured in situ, and kinetic studies of carbon formation to be performed at different partial pressures of CH4 and CO. 

Particulates (PM10, TSP, 0-5 g/m3 0.1 /ig/m3 Tapered element oscillating microbalance... 

Characterization of Catalysts under Working Conditions with an Oscillating Microbalance Reactor... 

Fig. 1. The tapered element oscillating microbalance reactor manufactured by Patashnick and Rupprecht (TEOM Series 1500 PMA Reaction Kinetics Analyzer). The term Cat. refers to the catalyst sample.

Volume 50 of Advances in Catalysis, published in 2006, was the hrst of a set of three focused on physical characterization of solid catalysts in the functioning state. This volume is the second in the set. The hrst four chapters are devoted to vibrational spectroscopies, including Fourier transform infrared (Lamberti et al.), ultraviolet Raman (Stair), inelastic neutron scattering (Albers and Parker), and infrared-visible sum frequency generation and polarization-modulation infrared rehection absorption (Rupprechter). Additional chapters deal with electron paramagnetic resonance (EPR) (Bruckner) and Mossbauer spectroscopies (Millet) and oscillating microbalance catalytic reactors (Chen et al.). 

Tapered Element Oscillating Microbalance (TEOM) studies of catalyst reduction (Gladden and McGregor, unpublished results). These studies also yield an average 1 1 relationship between vanadium atoms and oxygen atom loss. 

Zhu, W. Kapteijn, F. Moulijn, J.A., Diffiision of linear and branched C6 alkanes in silicalite-1 studied by the tapered element oscillating microbalance. Micropor. Mesopor. Mater. 47 (2001) pp. 157-171. 

There has been growing emphasis on the development and use of on-line measurements, which provide an abundance of data in real time. Short-term variations in aerosol composition can reveal great detail, as shown in Figure 12, which illustrates marked differences in the composition of the aerosol at an urban site over periods as short as tens of minutes. The mass concentration was measured by an oscillating microbalance whose frequency was altered by deposition of material. Ionic species were measured by subjecting the aerosol to supersaturation, which greatly increased particle sizes and permitted... 

The Tapered Element Oscillating Microbalance (TEOM) reactor has recently been applied to study deactivation of zeolite catalysts [7,8]. The main advantage of the TEOM reactor is that all gases in the reaction mixture are forced to flow through the catalyst bed as in a conventional fixed-bed reactor. Coupled with on-line gas chromatography, the catalyst activity, selectivity and coking rate can be measured simultaneously as a fimction of the amount of coke on the catalyst. Hence, the TEOM represents a unique way of studying the effect of coke deposition in detail. 

Kinetics and diffusion Steady-state isotopic transient kinetic analysis (SSITKA) Temporal analysis of products (TAP) Tapered element oscillating microbalance (TEOM) Temperature scanning reactor (TSR) Zero length chromatography (ZLC) Pulsed field gradient NMR... 

P-08 -Transient uptake measurements using an oscillating microbalance effect of acid leaching on the diffusivity of -hexane in Pt/H-mordenite... 

Measurements performed in a tapered element oscillating microbalance (TEOM) reveal that diffusivities can be derived from uptake data monitored under full reaction conditions. In this way the effect of acid leaching on the diffusional behaviour of w-hexane in Pt/H-Mordenite is investigated. It is shown that acid leaching largely enhances the -hexane uptake rate, but does not result in a net increase in the intracrystalline steady state diffusivity. It is concluded that the accelerated uptake after acid leaching merely arises from the shorter intracrystalline diffusion path resulting from the mesoporous structure. 

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