Computer-controlled graphics

A graphical comparison of process performance data to computed control limits drawn as limit lines on the chart. 

The complete packing process is computer monitored and computer controlled. Potential problems in column packing can be seen directly and the affected column is removed from the production cycle. Pig. 9.11 shows a graphic representation of a column packing process by monitoring the packing pressure with time. 

Sequential instruments. The diagram of the light path of the Thermo Electron-200 ICP spectrometer is shown in Fig. 20.14. The plasma is located in the upper centre of the instrument just above the nebuliser, which is powered by a computer-controlled peristaltic pump. Communication with the instrument takes place on a video display, which not only guides the operator through the use of the system, but also provides graphics to simplify methods development. 

Computer control technology, in silicon production, 22 505-506 Computer graphics... 

Nearly all mass spectrometers today are interfaced with a computer. Typically, the computer controls the operation of the instrument including any chromatography, collects and stores the data, and provides either graphical output (essentially a bar graph) or tabular lists of the spectra. 

Example of a graphic panel for a modem industrial plant with a computer-controlled system. (Courtesy of C. F. Braun and Company.)... 

Although crystal structure analysis was once a very time consuming and very expensive process, this has not been the case for a number of years. Structural results are usually available within two weeks of when a crystal is placed on the diffractometer instrument. This change has been due to a number of factors. Computer-controlled diffractometers have made data collection more accurate and much easier. The process of obtaining a trial structure has been much facilitated by the use of computerized direct methods and by computer graphics. 

A computer-controlled laser beam forms an image on a charged photosensitive drum. A carbon toner is applied and adheres to the charged areas, developing the image which is then transferred to the substrate and fixed with heat and pressure. Text, graphics and bar codes can all be produced this way. 

Several categories of analytical instruments were modified for continuous analyses in a process area. This usually involved interfacing the primary analytical instrument with a computer system, which would control the instrument, obtain the raw data, apply any calibration factors necessary and finally provide the chemist or engineer with the pertinent data in graphical and tabular form. A few of these instruments, such as gas chromatography, were already well accepted in the process areas and required only minimal development to capture and present the data in the desired form. Other instruments had rarely, if ever, been introduced in the process area and required extensive development for appropriate packaging as well as computer control, data acquisition, and graphical presentation. Examples... 

Square wave voltammetry is always performed using a computer-controlled potentio-static system with functional elements organized essentially as in Figure 7.3.11. The computer provides for operator interaction, synthesizes the waveform, sequences the sampling and logging of data, computes difference currents, and handles reporting of results, either graphically or otherwise. In many systems, the computer also controls the electrode, especially if an SMDE is involved. 

Another transducer resonance system is the Fokker Stack Tester, developed to examine ply orientation and stacking sequence in the different layers of CFRP composites. This computer-controlled system displays the signal output in a graphical format. It consists of passing a probe into a rivet or fastener hole and scanning the material surface by a focused laser beam. The intensity of the reflected light is correlated to the orientation of each ply and can provide information on the ply number, the thickness of each ply, and fiber orientation. 

An instrument that has transformed chemistry, just as it has transformed life in general, in recent decades is the computer. Just about all laboratory procedures, except the most primitive, are controlled by computers. As we have just seen, computers are intrinsic to X-ray crystallography, and are essential to the interpretation of diffraction patterns. They are also essential to modern NMR, where special techniques are used to observe the spectrum and need extensive mathematical manipulation to mine for the actual spectrum. There is, however, an application of computers in their own right, that of the computation and graphical portrayal of molecular structures. This is the field of computational chemistry . 

The use of computer databases and computer-controlled plants facilitates daily laboratory work. The recently set up expert systems for catalysts [79] help to reduce the number of experiments by rapid preselection, and accelerate catalyst development. In the structure determination of zeolites or non-zeolite molecular sieves (APOs, SAPOs), computers provide a valuable and fast service in that zeolite models are designed graphically on the screen, and the corresponding X-ray diffraction... 

Figure 11 Graphical illustration of a digital dual-core microreactor (DCM). The operation of the circuit was computer controlled using color-coded pressure-driven valves red, positive pressure, off/on yellow, peristaltic pumping green, vacuum.

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