Numerical filtering

By using the numerical filter to exclude all contributions except from the first shell. The inverse transform contains information then of only one term of the summation over j in y,(A) to give information about the number of nearest neighbours (IV,-) and the electron mean-free path (A) for the first shell. By... 

The procedures described above will work well in the ideal situation, where there is no noise in the data and the X-t curves represent the true conversion profiles so that the derivatives of the curves reveal the true rates. In practice there will be some noise in the raw data, and numerical differentiation notoriously amplifies noise, so that a straightforward application of these procedures is not likely to give satisfactory results. Instead, sophisticated numerical smoothing procedures must be used. The smoothing precedes the procedures presented above and leads to much more stable and accurate results by numerically filtering the data to remove experimental noise. The required filtering procedures are detailed in Chapter 7. 

Numeric filtering allows to keep fast variation of the signal for comparison widi an absolute threshold. The threshold has been determined in order to avoid spurious detection (less than 1 for 10 years of operation). 

Exhibitions are also ideal places to extract and obtain more information on advances in filtration equipment, and filter media in general is one of the most important of which is Achema (Frankfurt), where numerous filter equipment and media suppliers frequently exhibit.The Filtration Society also organises periodic exhibitions and conferences, referred to as Filtech, which are aimed primarily at chemical engineers and students who have a vested interest in the separation of soUds from liquids. Short courses often run concurrently with these conferences, which frequently feature an introduction... 

The nuances of a practical computational technique are often not clear from a discussion of the theory. With this in mind, an example of the Fourier transformation of an interferogram into a spectrum is illustrated for each step of the procedure. Only the Mertz method is shown, as this is the method commonly in use in commercial instrumentation. There is little reason to use the Forman method unless numerical filtering is to be applied. 

This instrument is presently being built by an international European consortium of scientific institutes, the Max Planck Institute for Astronomy (Heidelberg, Germany), the Astronomical Observatory of Torino (Italy) and the Max Planck-Institute for Extraterrestrial Physics (Munidi, Germany). CONICA has two filter wheels with each 20 filter positions (which can be combined to form numerous filter combinations) and detectors of at least 256 pixels. Detectors, filters and other items can be changed within seconds. Masks, filters, cold stops, grisms, polarization analysers, camera selection and detector selection, all can be chosen independently. 

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