On-line system

An expert system is a computer program that uses an experts knowledge in a particular domain to solve a narrowly focused, complex problem. An off-line system uses information entered manually and produces results in visual form to guide the user in solving the problem at hand. An on-line system uses information taken direc tly from process measurements to perform tasks automatically or instruct or alert operating personnel to the status of the plant. 

Many plants use off-line optimization. Off-line optimization is an open loop eontrol system. Instead of the elosed loop system, whieh eontrols the plant settings, data is provided to the operator so that he ean make the deeisions based on the findings of the operational data. Off-line systems are also used by engineers to design plants and by maintenanee personnel to plan plant maintenanee. Comparisons of the on-line systems to off-line systems ean be seen in Table 19-1. 

On-line system. Provides support for exposure assessments of toxic substances. Includes chemical properly estimation techniques, siahsiical analysis, multi-media modeling, and graphics display (including models)... 

A similar on-line LLF system, equipped with an on-line derivatization system, has also been reported. Brinkman and co-workers, for example, have presented a complete automated on-line system that allows both the LLF and alkylation of organic acids (38). More recently, this same group have reported the coupling of... 

Veterans Affairs will also begin rolling out an on-line system for personal health records. 

During the 1990s, much attention has been shifted to the development and utilization of on-line systems of extraction and analysis. The evolution of computers and... 

The second main reason for wastewater quality monitoring is related to process control, particularly for treatment plants where analysers and sensors are generally used with physico-chemical or biological reactors, including settling tanks. This application is mainly encountered for important wastewater treatment plants, either urban (majority domestic) or industrial, where the storage capacities are rather small with regard to the flow to be treated. Obviously, on-line systems are preferable in this case, but the available instruments often limit the choice. 

Hazards prevention can also be a reason for wastewater quality monitoring, in order to protect biological treatment plants from toxic shock loads, for example, or to prevent potential toxic effects on the receiving medium. This application is mainly found in industrial contexts where the presence of toxic pollutants may occur. In this case, on-line systems are obviously preferable for real-time warning. 

There are a lot of interesting inorganic constituents to be measured in waste-water, either metallic or non-metallic, but few of them can be measured with on-line systems. Table 9 presents a selection of recent works dealing with on-line/on-site monitoring systems for inorganic analytes. 

Except for the development of on-line systems for nutrients monitoring, the measurement of other inorganic non-metallic constituents is rather rare. Some commercial systems based on electrochemical sensing are proposed for the measurement of cyanide. A simple and rapid procedure for sulphide measurement in crude oil refinery wastewater has been developed [ 32 ]. Based on the de-convolution of the UV spectrum of a sample, this method has a detection limit of 0.5 mg L 1 and has been validated for crude oil refinery wastewater. 

In the last decade, for many toxicologists the on-line literature search has changed from an occasional, sporadic activity to a semicontinuous need. Usually, nontoxicology-related search capabilities are already in place in many companies. Therefore, all that is needed is to expand the information source to include some of the data bases that cover the types of toxicology information one desires. However, if no capabilities exist within an organization, one can approach a university, consultant, or a private contract laboratory and utilize their on-line system at a reasonable rate. It is even possible to access most of these sources from home using a personal computer. The major available on-line data bases are described in the following. 

Although the separation between some unwanted co-extractants and the analytes is well suited to an on-line system, high lipid or elemental sulfur loading is more effectively removed off-line. Most on-line systems at present work most effectively with low lipid contents [493,494], although some applications have overcome the problem of lipid removal. 

Koshigoe, S., T. Komatsuzaki, and V. Yang. 1999. Active control of combustion instability with on-line system identification. J. Propulsion Power 15 383-89. 

Roush PF, Seitz JT, Young LF (1979) An on-line system for storage and retrieval of polymer data. J Chem Inf Comp Sci 19 73-76... 

Compatibility between sensors and automatic and automated analytical systems is crucial as it allows two Analytical Chemistry trends to be combined (see Fig. 1.1). Probe-type and planar sensors can be used in automated batch systems including robot stations, as well as in continuous (mixed in-line/on-line) systems. On the other hand, flow-through sensors are only compatible with continuous configurations. 

Kuong JF. Audit and Control of Advanced/On-Line Systems. MAP-7. Management Advisory Publications, 1980. 

Research articles of interest to biochemists may appear in many types of research journals. Research libraries do not have the funds necessary to subscribe to every journal, nor do scientists have the time to survey every current journal copy for articles of interest. Two publications that help scientists to keep up with published articles are Chemical Titles (published every 2 weeks by the American Chemical Society) and the weekly Current Contents available in hard copy and computer disks (published by the Institute of Science Information). The Life Science edition of Current Contents is the most useful for biochemists. The computer revolution has reached into the chemical and biochemical literature, and most college and university libraries now subscribe to computer bibliographic search services. One such service is STN International, the scientific and technical information network. This on-line system allows direct access to some of the world s largest scientific databases. The STN databases of most value to life scientists include BIOSIS Pre-views/RN (produced by Bio Sciences Information Service covers original research reports, reviews, and U.S. patents in biology and biomedicine), CA (produced by Chemical Abstracts service covers research reports in all areas of chemistry), MEDLINE, and MEDLARS (produced by the U.S. National Library of Medicine and Index Medicus, respectively cover all areas of biomedicine). These networks provide on-line service and their databases can be accessed from personal computers in the office, laboratory, or library. Some... 

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