In Situ Instruments

Fig. 8.30 The Instrument Deployment Device (IDD) above the surface of Mars, showing all the four in situ instruments left) the MIMOS II with its contact ring can be seen in the front picture taken at Meridiani Planum, Mars right) MIMOS II is located on the left side picture taken at Gusev Crater, Mars...

The design of in situ atomic-resolution environmental cell TEM under controlled reaction conditions pioneered by Gai and Boyes (87,89) has been adopted by commercial TEM manufacturers, and latter versions of this in situ instrument have been installed in a number of laboratories. In situ atomic resolution-ETEM data demonstrated by Gai et al. (85-90) have now been reproduced by researchers in laboratories using commercial instruments examples include investigations of promoted ruthenium and copper catalysts in various gas environments (93) and detailed investigations of Ziegler-Natta catalysts (94). 

An alternative strategy is to make a large number of in situ measurements and examine how the balance between production and loss changes for different conditions. Particularly important are variations with altitude, because the relative importance of the various chemical families to ozone loss changes between 20 and 45 km. Seasonal and latitudinal effects are important for testing both the production and the transport of ozone. At present, the main source of data for these variations comes from satellite instruments, although in situ instruments have been used for several altitudinal studies, primarily by balloon-borne instruments, and some limited seasonal and latitudinal studies. 

The microphysics payload includes lidars (ABLE and MAL) and in-situ instruments for aerosol measurements (MAS). 

Table 6.2). In general, XPS of fresh catalysts shows mainly oxidized vanadium (V ). After reduction treatments, a decrease in oxidation state is observed. However, the extent of reduction depends on a number of factors, such as reduction temperature, reducing agent and partial pressure of the reducing gas, as well as the method used to transfer the reduced sample to the measurement chamber. Ideally, contact with air should be minimized, or excluded if possible, to prevent re-oxidation of the catalyst when the sample is transferred from a reactor to the UHV measurement chamber. This problem can be circumvented by in situ instrumentation as discussed later.

The in situ instrumentation must be inexpensive, rugged, and durable. 

Online, in-situ instrumentation to measure product composition has been developed to successfully determine the seed point, and is being utilized in an increasing number of crystallization operations. Image analysis or photographic methods may be useful in... 

Glud, R.N., Tengberg, A., Kuhl, M., Hall, P.O.J. and Klimant, L, 2001. An in situ instrument for planar Oj optode measurements at benthic interfaces. Limnol. Oceanogr., 46 2073-2080. 

In a planar cross-sectional slice of the tube volume subjected to examination for chemical change, as by in situ instrumental observation, one thus has continuously presented differential samples of the recently perturbed gas at successive distances behind the shock wave front. The thickness of the slice and the time inhomogeneity of the sample are mutually proportional, and these can be made typically 1 mm and a few sec, respectively. In the shock wave reflected at the tube end, the same gas sample may be viewed by stationary apparatus throughout an experiment in the incident wave flow, gas with a substantially common history flows through the observation region. 

Laboratory instruments are not subject to the operational constraints (e.g., power, mass, and volume) imposed on in situ instruments, which could make laboratory instruments more powerful and sensitive. This is often cited as justification for sample return missions. 

TLC coupled with spectrometry and other analytical methods, video documentation, and computer imaging (Chapter 9) quantification by video densitometry (Chapter 10) validation of quantitative results (Chapter 11) and in situ instrumental measurement of radioactive zones (Chapter 13). The fomth edition continues to provide extensive coverage of sample preparation in Chapter 3. We believe that this coverage is unique and differs from that found in other available treatises on TLC. Because of the primary importance of commercial precoated plates, detailed instructions for preparing layers were removed (Chapter 3), and description of documentation by contact printing has been eliminated (Chapter 9). 

Williams BJ, Goldstein AH, Kreisberg NM, Hering SV (2006) An in-situ instrument for speciated organic composition of atmospheric aerosols thermal desorption aerosol GC/MS-FID (TAG). Aerosol Sci Technol 40(8) 627-638. doi Doi 10.1080/02786820600754631... 

Abbreviations A automated sample application, D in situ instrumentalized detection, R automated chamber system, not applicable performance parameter, applicable performance parameter, number indicates the degree of importance or of difficulties. AC accuracy, LDQ lowest limit of quantitation, LLD lowest limit of detection. LR linearity and range, PR precision, REP reproducibility, RU ruggedness. SE selectivity. SL sample loadability, ST sample stability. 

The measurement of density with in-situ instruments to the required precision of 0.1 % is difficult to achieve—the advent of cold electronics should help [4]. 

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