Data, acquisition

Data acquisition applications are typically controlled by software programs that have been developed using various general-purpose programming languages. 

The most simple data acquisition device, which has been used by generations of automated nutrient analysts, is an analogue multi-pen recorder connected with the photometer voltage output(s). The recorded peaks can be evaluated graphically. Adjusting the delay coils of the manifolds (in multi-channel operation) to identical system times facilitates the sample/peak correlation. This method may be old-fashioned but still is an acceptable setup for testing and developing analytical manifolds. 

An analogue record of the spectrophotometer signals, or a corresponding hard copy generated by whatever acquisition system is used, provides a most valuable documentation of the performance of the analytical system and is the best insurance policy against data loss due to computer failures (a very conunon problem in ship operation of analysers). 

Commercial analysers generally include the hard- and software for data acquisition. However, any standard personal computer (PC, preferably colour display and printer) combined with an analogue-to-digital converting interface (ADC) are sufficient to provide the 

The AD-interface connecting the analyser and the data unit is an 8-channel serial AD-interface with 12-bit resolution. The ADC is based on a Linear Technology chip (LTC1290) and requires only a few additional components (a print board, complete with all components can be purchased for about 50 US from Conrad Electronic, D-92240 Hirschau). This interface is connected to a maximum of 8 spectrophotometer analogue outputs (or other instruments, e.g., an attached conductivity sensor) and to a serial port of the PC. One of the analogue inputs reads the sampler status. A serial ADC allows longer distance between wet analysis and dry data treatment (about 15 m). If parallel ADC interface cards mounted in the computer are used, the wet-analyser and computer have to be close together (less than 5 m). No additional hardware is required. 

The critical task for any nutrient analyser software is the determination of the peak height representing the component concentration. The peak shape depends on the sample volume and the mixing in the manifold. 

Principle of TOF mass spectrum acquisition with ITR in analogue mode. Data from JEOL documentation. 

With an 8-bit ADC, the intensity of the signal from the detector is converted into a numerical value that ranges from 0 to 255. To improve this small dynamic range, slow scanning instruments use typically 16- or 24-bit ADCs corresponding to intensity values from 0 to 65 535 or 0 to 16777215, respectively. Another possibility with fast scanning 

Since the TDC is a time counting device, when two or more ions arrive at the detector simultaneously in one flight cycle, the system counts them as one ion. In the same way, when two ions arrive at the detector in sequence within a certain interval, the system does not count the latter ion because the TDC is unable to register another count during the period after each ion event (counting dead time). Consequently, the dynamic range of this 

These saturation effects, resulting from the loss of ions due to the TDC dead time, can be statistically corrected by applying a correction factor [4], However, there is no effective correction when the quantity of ions increases and several ions arrive at the detector simultaneously. In conclusion, detection systems that operate in pulse counting mode are well suited to detect small quantities of ions by accumulation for a long period of time and when detection of individual ion events is important in order to obtain a good signal-to-noise ratio. 

Regardless of the selection of the kinetic model, data acquisition is always the first step of model development We obtain 2 months of feedstock/product analysis, productions, and operation data from the plant and construct multiple data sets to build and validate the model. It is important to consult plant engineers about data consistency to ensure each data set does not include the data in the period of operation upsets and significant operation changes. Moreover, it is always helpful to revisit the original data for the test mn, because test mn data are usually adjusted to show perfect mass and heat balances ]32]. 

Data required for the modeling purpose are quite sensitive to the selection of the kinetic model and the modeling scope. This work only requires the operation and analysis data measured daily, and Table 6.3 lists the data requirement in this work. We collect the data from March 2009 to June 2009 and organize the data 

From the elementary scheme in Fig. 2.3 It is apparent that data acquisition Is the stage lending itself most readily to automation as it establishes an on-line link between the Instrument and the computer. It Is Indeed an Important, delicate operation. The automation of data processing and result delivery Is ensured by the sole presence of the computer and the use of appropriate software. 

According to Barker [1], every measuring Instrument liable to automation features three essential components, namely the detector proper, the detector electronics and the display system. The signals generated by the measuring 

It is therefore obvious that computerized data acquisition Involves a number of essential factors such as the length of the experiment, the magnitude and frequency of the generated signals, the speed of data acquisition and the nature of the measuring Instrument, all of which have been given due consideration In the literature [3,8-11] and In reports on the use of digital 

The scheme In Fig. 2.6, reproduced from Barbara [16], Is Illustrative of a data acquisition system. The measured variable generates an electrical signal at the transducer whose nature and oscillation range Is matched to the ADC via a signal conditioner —usually consisting of one or several operational 

Starts loop and states 1024 pairs of data are to be taken Actuates the 1/0 unit Marks start of conversion by ADCs Input and storage of potentials intensities 

In this chapter, we have advocated the use of a computer for plotting the standard curve and performing the least squares fit procedure. Indeed, computers play a central role in the analytical laboratory for acquiring and manipulating data generated by instruments and for information management. 

The actual mode of connection between instrument and computer varies depending on the type of signal generated and the design of the instrument. The connection can be made via a serial port, a parallel port, or a USB port. The electronic circuitry required is built into the instrument s internal readout electronics or into an external box used for conditioning the instrument s output signal. In some cases, the instrument will not operate without the computer connection and is switched on and off as the computer is switched on and off. In other cases, the entire computer is built into the instrument. 

When in actual use, a software program is run on the computer that establishes the sampling time interval and other parameters at the discretion of the operator and begins the data acquisition at the touch of a key on the computer keyboard or at the click of the mouse. 

Having separated the ions of differing m/z values, a complete mass spectrum is obtained by determining the m /z ratios and relative numbers of each of the ions present. A description of these processes is beyond the scope of this present text and may be found elsewhere [2, 4], 

There are two ways in which we use mass spectral data, namely (a) for identification purposes, and (b) for determining the amount of an analyte(s) present in a sample (quantitation), with the ways in which we acquire data for these two purposes being usually quite different. 

For identification purposes, a mass spectrum covering all of the m/z ratios likely to be generated by the analyte is required. 

Very rarely, however, will a single mass spectrum provide us with complete analytical information for a sample, particularly if mass spectral data from a chromatographic separation, taking perhaps up to an hour, is being acquired. The mass spectrometer is therefore set up to scan, repetitively, over a selected m/z range for an appropriate period of time. At the end of each scan, the mass spectrum obtained is stored for subsequent manipulation before a further spectrum is acquired. 

Quantitation using mass spectrometry is no different to quantitation using other techniques and, as discussed above in Section 2.5, involves the comparison of the intensity of a signal generated by an analyte in a sample to be determined with that obtained from standards containing known amounts/concentrations of that analyte. 

RS232 serial port or IEEE488 interface bus). The plug-in cards use the computer power supply which tends to contain noise generated by all of the digital pulses generated in the computer. Higher bit conversion would not introduce improved measurement accuracy because of this noise. 

IF y(mX) mean + standdev OR y(mX) mean - standdev THEN numb numb - 1 GOTO marker END IF 

The discrete Fourier transform provides a useful and efficient means of extracting information on the frequency components present in a time-varying signal and displaying the amplitudes of these components as a spectrum. However, a number of potential artifacts must be avoided if we are to obtain a faithful representation of the information actually present in the time domain signal. 

The SIFT-MS instmment has two modes of operation (i) a mass scan mode (MS) in which a mass scan is made of all reagent iorrs and product ions over a selected mass-to-charge ratio, m/z. In the mass scan mode of operation, ion counts are recorded 

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In summary, exploration activities require the integration of different techniques and disciplines. Clear definition of survey objectives is needed. When planning and executing an exploration campaign the duration of data acquisition and interpretation has to be taken into account. 

The measurements are done at a table with two in X- and Y- direction moveable axes. The measured structures, by an Aluminium-alloy, are situated at the X-axis. The sensor at the Y-axis scans the structure step by step. The position and the electoral signal are measured for every step. A computer controls the movement of the sensor and the data acquisition. 

The system is equipped with an DEC- Alpha Station running at 400 MHz. Therefore the time for image reconstruction is not important compared to the time for data acquisition and preparation of the sample. 

The time for a measurement is determined mainly by the movement of the samples, because they are turned continuously during the data acquisition. If not prohibited by the geometry of the sample, a fast scan with 128 x 128 pixels is done in less than one minute. Scans of higher... 

Of course it is possible to calculate a complete three dimensional visualisation of the object on the base of many adjacent two-dimensional CT- sUces. By this method very detailed results can be achieved. But the total time of data acquisition increases proportional with the number of slices. 

Therefore it is reasonable to prepare already the data acquisition for a three dimensional evaluation in cone-beam-technique by means of two-dimensional detectors. The system is already prepared to integrate a second detector- system for this purpose. An array of up to four flat panel detectors is foreseen. The detector- elements are based on amorphous silicon. Because of the high photon energy and the high dose rates special attention was necessary to protect the read-out electronics. Details of the detector arrangement and the software for reconstruction, visualisation and comparison between the CT results and CAD data are part of a separate paper during this conference [2]. 

For several years, the French Atomic Energy Commission (CEA) has developed modelling tools for ultrasonic NDT configurations. Implemented within the CIVA software for multiple technique NDT data acquisition and processing [1,2], these models are not only devoted to laboratory uses but also dedicated to ultrasonic operators without special training in simulation techniques. This approach has led us to develop approximate models carrying out the compromise between as accurate as possible quantitative predictions and simplicity, speed and intensive use in an industrial context. 

The CamuS system consists of a number of components, both hardware and software, as shown in Figure 1. The hub of the system is the data acquisition unit, which collects and stores ultrasonic data in the form of RF waveforms. An accurate probe position monitor provides information on the location and orientation of the probe as it is scanned over the test object. Software tools have been developed to provide assistance to the user with preparing inspection procedures according to the requirements of prEN1714 with visualising the data, in relation to the test object with making measurements of any indications present and with classifying indications. 

This paper describes the procedure generation, data acquisition and data visualisation functions of the CantuS system. 

In order that the data acquisition system can obtain information about the spatial location and orientation of the probe, a four-channel incremental encoder interface board is installed. Three channels are used to define position in three-dimensional space, while the fourth monitors the skew of the probe (skew is defined as rotation about an axis normal to the probe face). Although six measurements are required to completely define the location and orientation, it is assumed that the probe remains in contact with the inspection surface. 

The complete advanced 3D inspection system contains three main components the Advanced Inspection Robot - AIR-1, the new generation P-scan ultrasonic data acquisition system - PS-4 and the 3D ultrasonic simulation system - UltraSIM. 

P-Scan System 4 Ultrasonic Data Acquisition System... 

We should also note that most of todays data acquisition systems are capable of producing enormous amounts of data which the traditional approach does not exploit for anything but verification of different ways to extract and combine features. To search in the. space of all such combinations is however a tremendous task. 

As we have mentioned, the particular characterization task considered in this work is to determine attenuation in composite materials. At our hand we have a data acquisition system that can provide us with data from both PE and TT testing. The approach is to treat the attenuation problem as a multivariable regression problem where our target values, y , are the measured attenuation values (at different locations n) and where our input data are the (preprocessed) PE data vectors, u . The problem is to find a function iy = /(ii ), such that i), za jy, based on measured data, the so called training data. 

Confocal microscopy requires serial data acquisition and processing and hence comprises a complete system whose cost exceeds that of a conventional microscope. 

The apparatus consists of a tip-position controller, an electrochemical cell with tip, substrate, counter and reference electrodes, a bipotentiostat and a data-acquisition system. The microelectrode tip is held on a piezoelectric pusher, which is mounted on an inchwomi-translator-driven x-y-z tliree-axis stage. This assembly enables the positioning of the tip electrode above the substrate by movement of the inchwomi translator or by application of a high voltage to the pusher via an amplifier. The substrate is attached to the bottom of the electrochemical cell, which is mounted on a vibration-free table [, and ]. A number... 

Direct time-dependent detection is limited by the response time of detectors, which depends on the frequency range, and the electronics used for data acquisition. In the most favourable cases, modem detector/oscilloscope combinations achieve a time resolution of up to 100 ps, but 1 ns is more typical. Again, this reaction has been of fiindamental theoretical interest for a long time [59, 60]. 

The first stage in data acquisition is the identification of the task that is, we have to know what kind of physical properties/biological activities we are going to model. 

According to an elegant remark by Davies [5], "Modem scientific data handling is multitechnique, multisystem, and manufacturer-independent, with results being processed remotely from the measuring apparatus. Indeed, data exchange and storage are steps of the utmost importance in the data acquisition pathway. The simplest way to store data is to define some special format (i.e., collection of rules) of a flat file. Naturally, one cannot overestimate the importance of databases, which are the subject of Chapter 5 in this book. Below we discuss three simple, yet efficient, data formats. 

A typical molecular dynamics simulation comprises an equflibration and a production phase. The former is necessary, as the name imphes, to ensure that the system is in equilibrium before data acquisition starts. It is useful to check the time evolution of several simulation parameters such as temperature (which is directly connected to the kinetic energy), potential energy, total energy, density (when periodic boundary conditions with constant pressure are apphed), and their root-mean-square deviations. Having these and other variables constant at the end of the equilibration phase is the prerequisite for the statistically meaningful sampling of data in the following production phase. 

Assuming that an equilibrium is now well established, the simulation may be restarted (not newly started) to begin with the sampling of structural and thermodynamic data. In our model case, data acquisition was performed for 3 ns (trajectory data plot not shown). For the production phase, also, the time evolution of the variables mentioned above should be monitored to detect stability problems or con-... 

Using MRI as a substitute for X ray tomography IS only the first of what are many medical applica tions More he on the horizon If for example the rate of data acquisition could be increased then it would become possible to make the leap from the equivalent of still photographs to motion pictures One could watch the inside of the body as it works— see the heart beat see the lungs expand and con tract—rather than merely examine the structure of an organ... 

Guidelines for Data Acquisition and Data Quality Control Evaluation in Environmental Chemistry, Ana/. Chem. 1980, 52, 2242-2249. 

With the availability of computerized data acquisition and storage it is possible to build database libraries of standard reference spectra. When a spectrum of an unknown compound is obtained, its identity can often be determined by searching through a library of reference spectra. This process is known as spectral searching. Comparisons are made by an algorithm that calculates the cumulative difference between the absorbances of the sample and reference spectra. For example, one simple algorithm uses the following equation... 

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