Computer software process

Mixtures can be identified with the help of computer software that subtracts the spectra of pure compounds from that of the sample. For complex mixtures, fractionation may be needed as part of the analysis. Commercial instmments are available that combine ftir, as a detector, with a separation technique such as gas chromatography (gc), high performance Hquid chromatography (hplc), or supercritical fluid chromatography (96,97). Instmments such as gc/ftir are often termed hyphenated instmments (98). Pyrolyzer (99) and thermogravimetric analysis (tga) instmmentation can also be combined with ftir for monitoring pyrolysis and oxidation processes (100) (see Analytical methods, hyphenated instruments). 

Sections 9.1.6 (c) and 9.2.1 (h) drew attention to the hazards of using old equipment. Similar remarks apply to old software except that, unfortunately, it never wears out. I do not know of any incidents in the process industries due to this cause, but it was responsible for the loss of the European space rocket Ariane 5. A function that no longer served any purpose was left in for commonality reasons, and the decision to do so was not analyzed or fully understood [14]. In another incident, cancer patients received excessive doses of radiation because operators were able to enter data faster than the computer could process them. This had always been the case, but originally a hardwired interlock had prevented... 

For purposes of this paper, the term "Data System" will refer to computer software designed to acquire data from an instrument or laboratory process, to manage and access that data, to analyze the data as required, and to plot and report the data and analysis results. 

Computer hardware/software Process electronic batch files through a computer system. 

An additional requirement not noted in Table 1 is compliance with GLP7 These practices establish a paper trail for all procedures involved in the determination of residues. With regard to immunoassays, GLPs require calibration of measurement devices such as adjustable pipettors and dedicated spectrophotometers. Computer software output, as noted above, must be verified prior to use. This process can be simplified by limiting the application of specialized software to the operation of an instrument and carrying out the residue calculations in a broadly available spreadsheet such as Excel. On a positive note, in recent years, the software accompanying most microtiter plate readers has become generally easier to use and usually incorporates internal spreadsheets that are compatible with external systems. 

Finally, the entire fault tree procedure enables the application of computers. Software is available for graphically constructing fault trees, determining the minimal cut sets, and calculating failure probabilities. Reference libraries containing failure probabilities for various types of process equipment can also be included. 

Data reduction and interpretation are much aided by computer methods and the high speed of current microcomputers facilitates the real-time processing and display of data. The principle of extracting as much information as possible from analytical measurements through the application of statistical and other mathematical methods, usually with the aid of appropriate computer software, is known as chemometrics (p. 13). 

Computer software is used to improve spectral quality. The most widespread procedures deal with averaging and background subtraction. The averaging process is rather obvious. The intensities of ions peaks at each m/z, recorded along the analyte chromatographic peak profile, are summed in several spectra and divided by the number of spectra used. Averaging minimizes, for example, spectral skewing problems. 

You can see that the model for a realistic process can become extremely complex what is important to remember is that steps 1 and 3 in Table 1.1 provide an organized framework for identifying all of the variables and formulating the objective function, equality constraints, and inequality constraints. After this is done, you need not eliminate redundant variables or equations. The computer software can usually handle redundant relations (but not inconsistent ones). 

The recent advancement in the field of computer technology and anlytical instrumentation it has become very easy and convenient to have the analyical data from a series of biological samples processed at high speed as digital readouts or on computerized recorders. Many hospitals round the globe make extensive use of advanced computer softwares for data processing as stated beiow ... 

Within the past few years the advances made in hydrocarbon thermodynamics combined wtih increased sophistication in computer software and hardware have made it quite simple for engineers to predict phase equilibria or simulate complex fractionation towers to a high degree of accuracy through software systems such as SSI s PROCESS, Monsanto s FLOWTRAN, and Chemshare s DISTILL among others. This has not beem the case for electrolyte systems. 

Figure 1 lists the major industrial processes that use thermodynamic data and the kind of data that are relevant. The design and use of distillation columns are the largest consumers of thermodynamic data. The feed stream to most industrial columns contains at least several components. The predication of the operating characteristics of such columns requires complicated calculations, and much computer software has been written... 

Regulatory authorities recognize that, in spite of all the control systems put in place, deviations and changes are sometimes inevitable. A robust GMP system includes procedures to handle, review, and approve changes in raw materials, specifications, analytical methods, facilities, equipment, processes, computer software, and labeling and packaging. All the changes have to be documented with references for traceability. 

In addition to the basic control loops, all processes have instrumentation that (1) sounds alarms to alert the operator to any abnormal or unsafe condition, and (2) shuts down the process if unsafe conditions are detected or equipment fails. For example, if a compressor motor overloads and the electrical control system on the motor shuts down the motor, the rest of the process will usually have to be shut down immediately. This type of instrumentation is called an interlock. It either shuts a control valve completely or drives the control valve wide open. Other examples of conditions that can interlock a process down include failure of a feed or reflux pump, detection of high pressure or temperature in a vessel, and indication of high or low liquid level in a tank or column base. Interlocks are usually achieved by pressure, mechanical, or electrical switches. They can be included in the computer software in a computer control system, but they are usually hard-wired for reliability and redundancy. 

A number of computer software packages are available to the analyst to assist in the planning and execution of both method development and validation experiments. The attraction of these systems is that they can automate the validation process from planning the experiment to test execution to the presentation of the data in a final report form. 

Increasing attention is being given to developing methods to predict failure rate data for process equipment and systems. Such methods are beginning to appear in published literature. These methods include correlations, factored estimation procedures, and analogies to predict equipment failure rates. They are desirable because they offer efficient means of providing equipment failure rate data for risk assessments, and they can be conveniently incorporated into computer software. 

A fire model is a physical or mathematical representation of burning or other processes associated with fires. Mathematical models range from relatively simple formula that can be solved analytically to extensive hybrid sets of differential and algebraic equations that must be solved numerically on a computer. Software to accomplish this is referred to as a computer fire model. 

Clearly the major difference between the 1990s and earlier times is the availability of inexpensive and rehable computing and control facilities. Time is a fundamental part of laboratory automation and, in the area of computer data processing, the rapid changes that have taken place over the last 25 years are quite startling. Results from analytical measurements can now be almost instantaneous. There is a ready access to computer power, commercial interface cards and even bespoke software. 

Validating computer software used to process and analyze a specimen. 

The ISO V model for system development life cycle in computer software validation is a structured description of such a process. In this instance, the basic V model has been adapted for analytical method validation and is shown in Figure 1. 

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