The use of computers

This section consists of a brief description of the sorts of computer software which are available for the recording and analysis of accident and incident data, and for a range of related data handling tasks. The criteria to be used in selecting software are also briefly discussed. 

There are many types of computer (usually referred to as hardware) but the most common type is the personal computer (PC), either in its desktop 

Before any application program can be run on a PC it has to be equipped with system software. This software does a number of things but essentially it is an interface between the hardware and any application program to be run. The major practical value of system software is that people who write, for example, statistical programs do not have to produce a different version for each different type of hardware. Instead, they write a program for a particular type of system software. The most common system software is Windows in its various versions and this discussion will be restricted to software packages which run under Windows. However many of the points made will also apply to other systems software. 

The sorts of programs discussed all operate in essentially the same way. Each one provides a framework, or shell, into which data can be put and, for the present purposes, the programs can be classified according to the types of data they accept. The main categories are as follows  

There is always an overlap between programs, for example word processors will do elementary calculations. However, all programs are designed to deal primarily with a single data type. Specific programs are dealt with after some general points. 

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Computer assisted operations (CAO) involves the use of computer technology to support operations, with functions ranging from collection of data using simple calculators and PCs to integrated computer networks for automatic operation of a field. In the extreme case CAO can be used for totally unmanned offshore production operations with remote... 

The solution adopted by us is the use of computer simulations of mathematical models of the process and the mock-up situations. Eventually, simulation techniques will become so accurate, that the mock-up step can be discarded. For the time being it is reasonable to use such models to generate corrections for smaller differences between mock-up and process. 

Although, the notion of molecular dynamics was known in the early turn of the century, the first conscious effort in the use of computer for molecular dynamics simulation was made by Alder and Wainright, who in their paper [1] reported the application of molecular dynamics to realistic particle systems. Using hard spheres potential and fastest computers at the time, they were able to simulate systems of 32 to 108 atoms in 10 to 30 hours. Since the work of Alder and Wainright, interests in MD have increased tremendously, see... 

The use of computers for the design of chemical syntheses was first demonstrated by Corey and Wipke in 1969 with their program OCCS [30]. The successor to OCCS, LHASA [31], is generally considered to be the first synthon-based system. Its development is still going on. Currently, three groups are working on LHASA, one at Harvard University, USA [32], one at the University of Leeds, UK [33], and... 

However, better use of spectral information for more rapid elucidation of the structure of a reaction product, or of a natural product that has just been isolated, requires the use of computer-assisted structure elucidation (CASE) systems. The CASE systems that exist now are far away from being routinely used by the bench chemist. More work has to go into their development. 

The first step in designing a new compound is to find compounds that have even a slight amount of usefulness for the intended purpose. These are called lead compounds. Once such compounds are identified, the problem becomes one of refinement. Computational techniques are a fairly minor part of finding lead compounds. The use of computer-based techniques for lead compound identification is usually limited to searching databases for compounds similar to known lead compounds or known to treat diseases with similar causes or symptoms. 

This book was designed to aid in research, rather than as a primary text on the subject. However, students may find some sections helpful. Advanced undergraduate students and graduate students will find the basic topics and applications useful. Beginners are advised to first become familiar with the use of computational chemistry software before delving into the advanced topics section. It may even be best to come back to this book when problems arise during computations. Some of the information in the advanced topics section is not expected to be needed until postgraduate work. 

Many of the topics covered in analytical chemistry benefit from the availability of appropriate computer software. In preparing this text, however, I made a conscious decision to avoid a presentation tied to a single computer platform or software package. Students and faculty are increasingly experienced in the use of computers, spreadsheets, and data analysis software their use is, I think, best left to the personal choice of each student and instructor. 

Once the peaks have been collected and stored, the computer can be asked to work on the data to produce a mass spectrum and print it out, or it can be asked to carry out other operations such as library searching, producing a mass chromatogram, and making an accurate mass measurement on each peak. Many other examples of the use of computers to process mass data are presented in other chapters of this book. 

Computer Control. The use of computer systems to control the operation of submerged arc furnaces, including calcium carbide, has been successfully demonstrated in the United States (see Expert systems Process control). Operations direcdy under control are mix batching, electrode position and sHp control, carbide gas yield, power control, and cooling water systems. Improvements in energy usage, operating time, and product quaHty are obtained. 

The second area, the implementation of a modem process monitoring and control system, is the most dramatic current appHcation of CAD/CAM technology to the chemical process industry. The state of the art is the use of computer graphics to display the process flow diagram for sections of the process, current operating conditions, and controUer-set points. The process operator can interact directly with the control algorithms through the... 

The use of computers is essential in probabilistic design (Siddal, 1983). However, research has shown that even the most complete computer supported analytical methods do not enable the designer to predict reliability with sufficiently low statistical risk (Fajdiga et al., 1996). Far more than try to decrease the statistical risk, which is probably impossible, it is hoped that the approach will make it possible to model a particular situation more completely, and from this provide the necessary redesign information which will generate a reliable design solution. 

A special mention is in order of high-resolution electron microscopy (HREM), a variant that permits columns of atoms normal to the specimen surface to be imaged the resolution is better than an atomic diameter, but the nature of the image is not safely interpretable without the use of computer simulation of images to check whether the assumed interpretation matches what is actually seen. Solid-state chemists studying complex, non-stoichiometric oxides found this image simulation approach essential for their work. The technique has proved immensely powerful, especially with respect to the many types of defect that are found in microstructures. 

Max Hansen and His Succe, sors Phase Diagram Databases 493 13-2.4 Other pecialised Database and the Use of Computers 497... 

R.G. Holdich, 1990, Rotary Vacuum Filter Scale-up Calculations - and the use of Computer Spreadsheets, Filtration and Separation, 27, pp 435-439... 

Parameter variation and optimization If parameter sensitivity is to be investigated, the simulation approach is cheaper and quicker than experiments. Trends are normally well predicted by the use of computer models. 

A Similar aphical presentation of the spatial distribution of a tracer g is or a real contaminant and thereby to some extent the airflow in the studied area is based on the use of computed tomography and optical remote sens-jt]g I2.M beams are sent out horizontally and reflected back to an IR analytical instrument, analyzing the average concentration of the contaminant along the IR beam. By combining data from several measured tines it is possible ro present data in a similar way to Fig. 12.8. Those methods presuppose access ro an expensive and complicated sampling/data processing system. 

As the use of computer networks become more widespread, auditing the practice against procedure will be possible without leaving your desk and can be carried out without the auditee knowing. 

The use of computers and microprocessors (also known as programmable electronic systems [PES]) in process control continues to grow. They have brought about many improvements but have also been responsible for some failures. If we can learn from these failures, we may be able to prevent them from happening again. A number of them are therefore described below. Although PES is the most precise descnption of the equipment used, I refer to it as a computer, as this is the term usually used by the nonexpert. 

The use of computer models to assist in plant layout decisions can often be helpful, but a clear understanding of what they can and cannot do is needed. Used blindly, they can lead to solutions which are, in some sense, optimal but which have little practical merit. 

Has the company or department the necessary knowledge of the computer system to prepare and implement a planned maintenance program by this method The benefits to be gained from the use of computers requires sufficient understanding of both computers and maintenance to foresee the advantages over those obtained from the manual system. 

Rack design is important in obtaining uniform deposits and good coverage in view of the low efficiency of the bath. The use of computer modelling has been examined for this purpose . 

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