Computers spreadsheets

The approach that we have worked out for the titration of a monoprotic weak acid with a strong base can be extended to reactions involving multiprotic acids or bases and mixtures of acids or bases. As the complexity of the titration increases, however, the necessary calculations become more time-consuming. Not surprisingly, a variety of algebraic and computer spreadsheet approaches have been described to aid in constructing titration curves. 

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. 

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

Table 7.1 shows the construction of a typical activity chart using one of many computer spreadsheet packages. The cross (-F) identifies an activity in the plant and stars ( ) in the vertical lines denote where access to other activities is needed or an interrelationship exists. A wide scattering of the stars away from the diagonal line of crosses indicates large distances between the activities and thus large communicating distances. 

The amounts of sulfentrazone, SCA (analyzed as DMS), and HMS were quantitated by an external standard calibration method. A computer spreadsheet program (Microsoft Excel) was used for calculation and reporting. 

Most of the algorithms and formulae discussed in this chapter can be implemented as expressions in computer spreadsheets, and the rest as simple computer programs. Most are also incorporated into the Microsoft Excel spreadsheet program by the Isoplot add-in (Ludwig 1999, in press) as user-available functions and graphical routines (Appendix III). 

Example. The following personal computer spreadsheet will solve Eq. (56) with an added loading dose for any time during a repetitive dosing regimen (see Fig. 15). 

A simple linear regression is very easily computed with an ordinary computer spreadsheet program such as Lotus 1-2-3 or Microsoft Excel. The method involves calculating first the average values of x and y, then the values of Co and Ci, and then the estimated value of y ... 

Many companies have developed their own factored estimates using computer spreadsheets based upon their in-house experience and cost database information that they have built from company project history. For detailed estimates, the job is outsourced to design-construction companies that have the staff to perform those estimates. 

If you already use a spreadsheet, you can skip this section. The computer spreadsheet is an essential tool for manipulating quantitative information. In analytical chemistry, spreadsheets can help us with calibration curves, statistical analysis, titration curves, and equilibrium problems. Spreadsheets allow us to conduct what if experiments such as investigating the effect of a stronger acid or a different ionic strength on a titration curve. We use Microsoft Excel in this book as a tool for solving problems in analytical chemistry. Although you can skip over spreadsheets with no loss of continuity, spreadsheets will enrich your understanding of chemistry and provide a valuable tool for use outside this course. 

It is important to use the most accurate values available for these ratios and to do the calculation on a computer spreadsheet to avoid truncation errors. Once you have the frequency corresponding to 0 ppm, the chemical shift at the center of the spectral window ( the carrier ) can be calculated from the reference frequency of the 13C or 15N channel as we did above for the ll channel. 

Failure to use fully validated computer spreadsheets to calculate analytical results for in-process and finished product testing [21 CFR 211.165(e) . For example, the computer spreadsheets used to calculate analytical results for [redacted] have not been validated. 

Regarding the validation of computerized spreadsheets used for in process and finished product analytical calculations (FDA-483, 4), your response states fiiat current spreadsheets were challenged using the proposed revisions to SOP 644, QA/QC Computer Spreadsheet Validation. However, your response does not indicate if computerized spreadsheets for all products which use file spreadsheets were challenged using the proposed revisions to SOP 644. 

Holdich, R. G. (1990). Rotary vacuum filter scale-up calculations—and the use of computer spreadsheets. Filtration and Separation. 27, 435-439. 

For example, before inventing Quicken software, Intuit observed people struggling to do the job of organizing and managing their personal finances. Even though professional-caliber accounting software was available at the time, many individuals were using computer spreadsheets or pencil and paper to accomplish this job. None of these approaches met the expectations of home users as well as Quicken does today. 

Consider whether additional columns are required for subsequent calculations. Create a separate column for each mathematical manipulation, so the step-by-step calculations are clearly visible. Use a computer spreadsheet (p. 307) if you are manipulating lots of data. 

Many reagent chemicals used in the lab are sold in the form of concentrated aqueous solutions, as shown in the table below. Different volumes are diluted to 1.00 L to make less-concentrated solutions. Create a computer spreadsheet that will calculate the volume of concentrated reagent needed to make 1.00 L solutions of any molar concentration that you enter. 

The use of this method has become increasingly popular as the availability of commercial software that allows the probability distribution functions to be input directly into a computer spreadsheet have become available. Once the probability distribution is incorporated into a spreadsheet cell, each time the spreadsheet is recalculated, a new value for the random variable is selected from the distribution and used in the calculations. The key to appropriately using this method is to run the entire simulation (choosing random samples from each distribution) hundreds to thousands of times. After each selection, a new representative parameter is generated and can be used as the basis for an estimate of exposure or risk. When the method is used to calculate risk or exposure, the results of all risk estimates are... 

Bayes theorem provides a method to calculate the probability of a disease after the addition of new information to previously obtained information. These formulas can be incorporated into computer spreadsheets and other computer aids to help in the estimation of updated probabilities. One method, which can be performed without a computer, involves using the odds ratio version of Bayes theorem. The odds ratio of the occurrence of a disease is calculated before the test result is known this information is then combined with the results of the test in the form of a likelihood ratio. The final result is again in the form of an odds ratio this can be converted into a probability, if desired. The advantages of this method are that it is relatively easily memorized and that it requires little mathematical calculation. The odds ratio is useful when it is combined with the likelihood ratio in a more memorable form of Bayes theorem ... 

The third set of tools involves the pharmacist s documentation of interventions and results. If lipids are to be measured and followed, the use of a monitoring flow sheet is extremely useful (Fig. 1). Flow sheets may be on paper files, created on computer spreadsheets, or use special software programs. 

I made up a computer spreadsheet, which showed the differences between my machine and my competitor s machine. The spreadsheet analyzed the time savings advantage of using my machine and also the reliability factor of each machine. When I figured in the time cost savings and repair costs, it turned out that my machine would actually be less expensive. 

Figure 5.2 explains how Shannon entropy works. Expression data must be binned for this calculation, which can be performed with spreadsheet software. Fuhrman et al. [14] contains instructions for calculating Shannon entropy in a computer spreadsheet. The number of bins is determined by the number of time points in the series, and should be < log (base 2) of the number of time points (Bruce Sawhill, Santa Fe Institute, unpublished). So, for fewer than eight time points, two bins may be used for eight or more time points, three bins for 16 or more, four bins, etc. It is preferable to use a large number of time points, in part to help avoid the problem of binning artifacts caused by expression values that lie close to bin boundaries. 

A computer spreadsheet may be very useful in repetitive calculations or for what if case studies (see Chapter 47). 

Parameterization and Tracking of Optimization of Synthesis Strategy Using Computer Spreadsheet Algorithms... 

With the widespread availability of hand-held calculators, computer spreadsheets, and statistical software packages for PCs, there is no need to do the calculations outlined above by hand. 

Calculate Gqq for the 11 data points in Table 11.1. This is best done with a computer spreadsheet, but can be done by hand. 

---