The HSC suite also calculates Pourbaix, or Eh-pH, diagrams that provide a visualization of the equilibria involving user-selected ionic and non-ionic species in an aqueous solution. A main menu permits the selection of elements of interest; the program then searches the database to find all species containing the specified elements. After saving a file containing the selected information, the routine calculates the free energies of the species at the specified temperature. With the click of a button, the Pourbaix diagram appears and shows regions of stability for the selected species on a plot of potential pH. The user has the option of printing the diagram or saving it as a Windows metafile which can then be converted to other graphicsfiletypes for importing into word processors or presentation packages The HSC suite of routines was installed easily and flawlessly on a 66-MHz 486 machine and on a 60-MHz Pentium machine running under Windows 3.1 and Windows 3.11, respectively. No software glitches were detected during many hours of experimentation on each machine. Numerous examples of calculations from standard physical chemistry and thermodynamics texts were tested using the HSC routines, and the results obtained were acceptably accurate. Apparent small differences could be ascribed to the sources of the original thermochemical data. There is ample context-sensitive help available in each routine to assist the novice user The various windows of the HSC Chemistry package are constructed thoughtfully to make navigation of the software straightforward The graphical user interface of the HSC suite of routines is at a relatively low level of development compared to the glitzy software that most Windows users are accustomed to This lack of glitz does not detract, however, from the utility of the package. The user interface in the reaction equation routine could stand some improve-
ment. The user often has to use trial and error to determine whether a given species is actually in the database. If, while entering a reaction, the user had access to a pop-up window containing the database, species could be selected directly and exactly as they appear. The HSC package does not appear to have been designed as a learning tool, but rather as a tool for practicing chemists who have thorough knowledge of thermodynamics; consequently, the learning curve of the program is relatively steep. To quote the manual, "Although equilibrium calculations are easy to carry out with HSC Chemistry, previous experience and knowledge of the fundamental principles
One of the moss potentially useful routines iisth equilibrium calculation option.
SOFTWARE RELEASED SigmaGel Sigma-Aldrich Techware
P.O. Box x 14508 St. Louis, MO 63178
800-325-3010; fax 800-325-5-50 $495 SigmaGel, a Windows-based drogram designed for gel analysis, allows researchers to make lane, spot, and molecular weight measurements from gels scanned by a TWAIN-compliant scanner. The procedure is icon-driven and the resulting spreadsheet data, graphs, and images can be output to any Windows-supported device. A context-sensitive Help feature provides online assistance. SigmaGel requires a 486-33 or higher PC equipped with Windows 3.1 or higher, 8 MB of RAM, 5 MB of hard disk space, and a 226color VGA monitor. Instrument Maintenance and Calibration System WindowChem Software 420 Executive Court North, Suite F Fairfield, CT 94585
707-864-0845; fax 707-864-2815; of thermodynamics are also needed. Othinternet httpJ/www. windowchem. com erwise, the probability of making serious $249 errors in basic assumptions is high." Engineers and chemists in the industrial Instrument Maintenance and Calibration realm should find the package useful for System ((MCS) )i a Wiinows-based dataexploring potential reactions before debase program designed to track laborasigning and setting up pilot reactors for tory instruments and equipment throughnew processes. Although I do not think out their lifetime to maximize their that the package is appropriate for teachusefulness. The program allows the user ing lower level undergraduate courses, it to maintain a large database of informamay be useful in advanced courses in tion on instruments in a single, userphysical and analytical chemistry at the friendly environment and simplifies instrugraduate and undergraduate levels. The ment scheduling, logging, and reporting HSC Chemistry package is reasonably and tracking of preventive maintenance, priced, considering the large database and calibration, and inspection. IMCS rethe functionality of the various modules. quires a 386 or higher PC equipped with Windows 3.1 or higher, 4 MB oo RAM, and Reviewed by F. James Holler, University 7.5 MB of hard disk space. of Kentucky, Lexington
