Data acquisition methods

Off-line. A data-acquisition method in which the mass spectra are produced some time after the original experiment. 

While steady-state data provide a snapshot of the machine, dynamic or real-time data provide a motion picture. This approach provides a better picture of the dynamics of both the machine-train and its vibration profile. Data acquired using steady-state methods would suggest that vibration profiles and amplitudes are constant. However, this is not tme. All dynamic forces, including mnning speed, vary constantly in all machine-trains. When real-time data acquisition methods are used, these variations are captured and displayed for analysis. 

The production of the agrochemical 6 (Scheme 5.7) is carried out batchwise via a three-step protocol. Mass balancing has been conducted for three stages of development Laboratory-, pilot- and operation scale. An LCA was available for the operation stage only. A description of this LCA including data sources and data acquisition methods was published by Geisler et al. (product A in reference [9] corresponds to product 6 here). Many parameters in the Life-Cycle Inventory (LCI) are estimated, especially utihty demands and yields of processes for the production of precursors. Uncertainty in these estimations was illustrated in a... 

In the earliest SFG experiments [Tadjeddine, 2000 Guyot-Sionnest et al., 1987 Hunt et al., 1987 Zhu et al., 1987], a first-generation data acquisition method was used, and, because of the limited signal-to-noise ratios, IR attenuation by the electrolyte solution was a substantial handicap. So, in earlier SFG studies, as in IRAS studies, measurements were performed with the electrode pressed directly against the optical window [Baldelli et al., 1999 Dederichs et al., 2000]. With the in-contact geometry, the electrolyte was a thin film of uncertain and variable depth, probably of the order of 1 p.m. However, the thin nonuniform electrolyte layers can strongly distort the potential/coverage relationship and hinder the ability to study fast kinetics. 

We tested this data acquisition method by first ablating bracketing concentration standard glasses that had been determined from previous measurements. All the samples in this analysis had total strontium elemental concentrations between 95 and 350 parts per million strontium. We then collected 150-300 one second ion count packets for MSr, Sr, 87 Sr and 88Sr, plus the instantaneous ratio of each isotope to Sr (Figure 3). 

The proper response is dependent upon the data acquisition method used. The means to select a specific method will be discussed. If an ensemble averaging method is used, then the spectral rate is the number of spectra to be averaged. 

Figure 13. Diagram illustrating the data acquisition method for the computer-controlled measurement of Raman and ROA spectra at Syracuse University.

In contrast, there are just two such files used within the Analyst data acquisition method (DAM) and instrument file format (INS) files. The mapping of the MassChrom and Analyst files is not one to one parameters in the experiment file are split between the INS and DAM files on the Analyst application. 

ExptFile Converter — Experiment file conversion program that combines a Macintosh state file and a Macintosh experiment file and generates an Analyst data acquisition method file (DAM). 

Which brings us to a related point. Modern computer-based data acquisition methods sometimes show a low-frequency oscillation superimposed on the signal. Say that we have a transient signal decaying with a time constant of 0.1 s, and sampled with a 20 ms. Any 60 Hz pick-up will then show as a 10 Hz oscillation, i.e., as the beat frequency between the sampling rate of 50 Hz and the 60 Hz pick-up. Fig. 7.4-9a illustrates this. 

Time resolution of changes in the mass spectra can be accomplished in several ways. A TOFMS accessory is available from CVC Products, Inc. (Rochester, NY), which rasters mass spectra across the oscilloscope screen both vertically and horizontally. This device counts a preset number of spectra, n, and then oflFsets the trace both vertically and horizontally. After n more spectra, the trace is again offset. This procedure continues up to the desired number of traces. The device can be used to display 1 16 traces with 1-64 spectra per trace, thus permitting time resolution as low as 0.1 msec. However, the total display time, 16 traces times 64 spectra/trace, is only 0.1 sec. Thus, synchronization of sample loading and/or failure with this data acquisition device is critical. This data acquisition method provides both quantitative and qualitative data about the evolved compounds. However, the mass range which can be displayed effectively is limited to about 100 amu. 

Adoption of fast and parallel data acquisition methods... ... 

Signal Modulation and Related Data Acquisition Methods... 

Electrochemistry is a field, where control of experiments and data acquisition methods do not differ greatly, but proper interpretation of measured data gives information on several different phenomena. In electrochemical experiments one controls the system with electrical quantities and also measures electrical quantities, i.e. voltage and current. The electrochemical corrosion process, its probability and rate can be described as a function of three variables potential, current and time. Other electrical and electrochemical parameters can be derived from these variables. As an electrochemical process, corrosion can also be studied with electrical measurement methods. The measurements are suitable for automation which has the following advantages ... 

This chapter has reviewed the fundamentals of the design of ultrasound scanners with a particular focus on the beam formation process. Different types of image data acquisition methods are described. 

McConnell, E. 1995. Choosing a data-acquisition method. Electronic Design 43(13) 147-156. 

The reciprocal lattice provides a simple way to illustrate the positions of diffraction points in space. Figure 4 also shows that the Ewald limiting sphere determines how many reflections can be measured. All reflections inside the limiting sphere with radius 2/A are obtained only if the crystal axis AB can take up any orientation. This is not so in many data acquisition methods, e.g., the rotating crystal method. If the crystal is rotated... 

Murase K, Tanada S, Higashino H et al. (1989) A unified computer program for assessment of attenuation correction and data acquisition methods in single photon emission computed tomography (SPECT). Eur J Nucl Med 15 284-253... 

The acquisition and study of the spectra of selected precursor ions, or of precursor ions of a selected neutral mass loss. Structure selective target analyte quantitations use SRM/MRM data acquisition methods. MS/MS can be accomplished using beam instruments incorporating more than one analyser (tandem mass spectrometry in space, triple quadrupole analyzer) or in trap instruments (tandem mass spectrometry in time). 

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