Accelerators computer controls

The output of a Nd YLF laser is focussed by a series of lenses to a spot size of 0.5 pm upon a sample which may be positioned by an x-y-z stepping motor stage and scanned by a computer-controlled high frequency x-y-z piezo stage. Ions are accelerated and transmitted through the central bore of the objective into a time-of-flight (TOF) mass spectrometer. The laser scans an area of 100 x 100 pm with a minimum step size of 0.25 pm. TOF mass spectra of each pixel are evaluated with respect to several ion signals and transformed into two-dimensional ion distribution plots. 

Young, N.D. Holland, J.F. Gerber, J.N. Sweeley, C.C. Selected Ion Monitoring for Multicomponent Analyses by Computer Control of Accelerating Voltage and Magnetic Field. Anal. Chem. 1975, 47, 2373-2376. 

These modern computer controlled ignition systems use multiple sensors to determine optimum firing. This may include double pick-up sensors on the flywheel to determine rpms under acceleration and deceleration, intake and atmospheric pressure compensation, oxygen sensor levels to maximize combustion, temperature sensors and exhaust emission sensors. All this data is constantly fed into the on-board computer and processed using complex algorithms to determine optimum firing and fuel consumption levels. 

Since pressurized fluid extraction (PFE), also known as accelerated solvent extraction (ASE ), is a relatively new technique, the commercial availability of PFE instruments is limited. A commercial PFE system ( ASE 200 ) currently available is a fully automated sequential extractor developed by the Dionex Corporation, USA. This mainly consists of a solvent-supply system, extraction cell, oven, collection system and purge system, all of which are under computer control. A schematic diagram of a PFE system is shown in Figure 7.15. This system (ASE 200) can operate with up to 24 sample-containing extraction vessels and up to 26 collection vials, plus an additional four vial positions for rinse/waste collection. 

The piston is moved back and forth by a cam-driven plunger powered by a computer-controlled motor (Fig. 6.3) one-way directional check valves (usually ball-style valves) are needed. The cam driver can accelerate and change the flow rate smoothly throughout the entire length of each stroke. Reproducible pulseless flows are generated and compatibility... 

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... 

The development of powerful computer controls and programs has greatly accelerated integrating process variables with a goal of zero defects at the... 

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