Hardware array

In order to prepare the system for 3D-CT, it is not enough to integrate a second detector array. Besides this special attention has to be paid to the computer hardware, the synchronisation between object movement and the data read out as well as to the collimator of the LINAC. The collimator has been built with 4 tungsten blocks which can be moved individually m order to shape different sht sizes for 2D-CT as well as different cone angles for 3D-CT or digital radiography. 

In order to operate a process facility in a safe and efficient manner, it is essential to be able to control the process at a desired state or sequence of states. This goal is usually achieved by implementing control strategies on a broad array of hardware and software. The state of a process is characterized by specific values for a relevant set of variables, eg, temperatures, flows, pressures, compositions, etc. Both external and internal conditions, classified as uncontrollable or controllable, affect the state. Controllable conditions may be further classified as controlled, manipulated, or not controlled. Excellent overviews of the basic concepts of process control are available (1 6). 

In the field of chemical sensors, the revolution in software and inexpensive hardware means that not only nonlinear chemical responses can be tolerated, but incomplete selectivity to a variety of chemical species can also be handled. Arrays of imperfectly selective sensors can be used in conjunction with pattern recognition algorithms to sort out classes of chemical compounds and thek concentrations when the latter are mixed together. 

Topics which will be presented in this chapter include the hardware, software, automation, valve and column configurations, and integration used in comprehensive 2DLC. Aspects of the 2DLC experiment in conjunction with multichannel detectors such as UV diode array optical detectors and mass spectrometers are discussed along with the handling of the data, which is expected to expand in scope in the future as chemometric methods are more widely used for data analysis. 

The spectrometer supports phase cycling, asynchronous sequence implementation, and parameter-array experiments. Thus, most standard solid-state NMR experiments are feasible, including CPMAS, multiple-pulse H decoupling such as TPPM, 2D experiments, multiple-quantum NMR, and so on. In addition, the focus of development is on its extension of, or modification to, the hardware and/or the software, in the spirit of enabling the users to put their own new ideas into practice. In this paper, several examples of such have been described. They include the compact NMR and MRI systems, active compensation of RF pulse transients, implementation of a network analyzer, dynamic receiver-gain increment,31 and so on. 

Advances in instrumentation, such as diode arrays and ruggedized interferometers, have made IR and Raman instruments readily available for process work. NIR hardware has always been used more for production and quality control than laboratory and research work. They, too, have become smaller, faster, more rugged and, in 1980s dollars, less expensive. Explosion-proof enclosures allow close proximity to reactors containing solvents and can be operated in dusty locations (raw material handling situations). 

Because NIR was initially used for food and agriculture products, it has evolved as a technique for complex matrices. Many types of hardware have become available for NIR work interference filters, gratings, interferometers, diode arrays, and acousto-optic tunable filters. And, as it was originally developed for complex mixtures, chemometrics has been an integral part of any NIR analysis for the last few decades. NIR practitioners are quite comfortable with multivariate equations and development of equations for complex matrices. 

In practice, a particular phase cycle is defined by means of an array of RF pulse settings (to be used cyclically during consecutive scans) and an associated array of receiver phases . The receiver phase , however, does not correspond to any hardware device setting. Rather, it is an interlocution for the various modes of how each single-scan signal should be handled by the data accumulation procedure (add, subtract, quad add, quad subtract, etc.). 

Although not yet available, it is likely that Web-based performance testing systems will become available in the near future. Web-based systems will permit selected tasks to be presented on computers equipped with appropriate Web browser software. Hardware requirements include Internet access and appropriate memory and software to support Web-based applications. Depending on the design of the Web-based system, it is could be possible to tailor the specific tasks presented for the performance testing system from a menu of options. Alternatively, testing systems consisting of a standardized array of tasks can also be chosen. As such, the start-up costs of Web-based systems should be lower than with personal or handheld computer systems. Subject identification, date, and time can be recorded at the start of a test, and data from multiple subjects and test occasions can be stored in a central file for easy access to the data. 

Single processor calculations of nuclear shielding at the SCF level are limited by practical computation times in most hardware to about 800 basis functions with no symmetry or 1600 with high symmetry. Thus, the obvious solution of the problem is parallel processing using an array of inexpensive workstations or PCs. In a significant breakthrough, Peter Pulay et al. have implemented the first parallel computation of... 

Fig. 3.9 Secondary impregnation workflow showing the precursor preparation station, support preparation, impregnation station, washing station, thermal processing hardware, and impregnated catalyst array.

Computer Hardware. The use of a computer for data acquisition and control is mandatory because of the clock frequency used by the Reticon array (20 kHz) and the volume of data that it is capable of outputting. A PDP-8e computer made by Digital Equipment Corporation, with 12 K words of memory was employed. 

The second hardware unit was an interrupt, skip-check control unit for the Reticon arrays. This unit allows the computer to see the end-of-scan and beginning-of-scan pulses generated by the arrays and allows the computer to have an on/off control of the external clock which is used to start the analog to digital converter. 

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