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Welcome to the The Unit Converter page, part of the Utility Applet Library of TEST, The Expert System for Thermodynamics. TEST is a network of HTML pages with embedded Java Applets that help users solve thermodynamic problems visually and perform parametric studies without any programming. Although TEST is being accessed mostly by thermal-science professionals from over 90 different countries, the Unit Conversion Utility is designed for general use by anyone. After all, who has not encountered competing units such as Celsius vs. Fahrenheit, acre vs. hectre, kg vs. pounds etc. And some of the unfortunate ones have to struggle with more esoteric units such as Therm, centipoise or bars in their daily life without ever memorizing the appropriate conversion constants.

This Unit Converter is designed to be an one-stop utility for all your unit conversion needs (except if you are a foreign exchange trader). What distinguishes this converter from other similar applications is its ability to learn from the user. If you find a particular unit or even a category of units missing, simply type those in. Within a week you will find your suggestions at work.

The examples below contain images of the applet in action. Once you get a rough idea about how the applet works, you can start using the real thing following these instructions.

There are two ways of doing anything, the quick way and the right way.

If you are in a hurry, do the following: (a) Browse the examples below (takes only a minute), and (b) Launch the customized Java applet (called a daemon) by clicking the appropriate link at the top of this page. If you have a modern browser (Netscape 4.5 or better, Microsoft IE 4.0 or better), the daemon will appear in about 10-50 seconds (1 second if you are running from a locally installed TEST) and you can start exploring.

To fully exploit TEST follow thest steps: (a) Start the Introduction/Turorial for the Expert System by clicking the link at the top of this page. (b) Explore a few daemons as explained in the tutorial. (c) Browse a few topics of your choice from the Slide Show. (d) Once you understand the algorithm TEST applies for locating the right daemon for a given problem, you can use the TEST-Map to quickly launch a desired daemon. Of course, all these may take better part of an hour - but, trust me, you will not regret it.

 

Example-1: An utility company charges 10 cents per kW.Hr for electricity and 50 cents per Therm of gas. How expensive is electricity compared to gas? Solution: Obviously, the only engineering task in this problem is to find the conversion factor between kW.Hr and Therm, which are both units of energy. To bring up the appropriate daemon (applet) navigate to Test, Daemons, Basics, Units, and UnitDaemon in sequence (or directly using the Unit Converter link at the top).  The daemon page should be displayed on the upper frame. Scroll down the frame (and drag down the divider, if necessary) to display the daemon (enclosed within a green rectangle) squarely on the upper frame. As the daemon gets loaded, you may see its shadow for about 5-15 seconds.  Trouble Shooting: If the daemon (as pictured below) does not show up even after a minute, may be your browser is unable to run Java applications. I know of three reasons for this. (i) Your browser has not been updated since the Jurassic age, (ii) Java is turned off, (iii) Security is set to 'high' (in case of Internet Explorer). Because TEST takes advantage of JDK 1.2 (the latest Java revision), you will need Internet Explorer 4.0 or Netscape 4.5 (not 4.05) to run TEST effectively. If you do not want to update your browser, you can still use TEST-2.01, a relatively primitive version. Instructions for how to rectify these problems and links to download the latest version of the browsers (Navigator or Explorer) can be found in the Troubleshooting/FAQ file on the TEST Home Page. If the daemon looks 'broken' (happens occasionally with Explorer 4.0) close (not exit) and open the browser to refresh the display.  Fig. 1. Image of the unit conversion applet (Units Daemon) producing solution to Example 1. Select the quantity, energy in this case, from the central list (you may have to scroll down the list to find 'energy'). Adjust the unit lists to the selected quantity. Select Therm from the left list and kW.H from the right. The daemon displays the conversion factor of 29.3. The rest of the problem is trivial. Now, try to convert mph into m/s, or centipoise to lbm.ft/s. Notice the message panel (a line of text with a blue background) that appears at the bottom of the daemon, a feature common to most of the daemons.

 

Example-2: How cold is the weather if the Celsius and Fahrenheit thermometer produce the same reading? Solution: To bring up the appropriate daemon (applet)follow the same procedure as in Ex. 1.  Once the applet shows up, select the appropriate category, temperature in this case, from the central list. Choose 'deg C' and 'deg F' from the left and right list. Now try different numbers on the yellow field to get a feel for how the two scales are related. You will soon find the correct answer. Notice that as you select the category, all the available units are displayed in the two lists. To suggest new units or even a new category, a user simply fills out the form below the applet.     Fig. 2. Image of the unit conversion applet (Units Daemon) producing solution to Example 2.

These examples are only meant to give the reader the flavor of a daemon (applet). Many more examples of solved problems, grouped into fifteen different chapters, can be found under TEST Home Page> TEST> Problems page. Before you start using this particular applet, it is strongly recommended that you take a look at the 'Slide Show' to get a feel for the breadth of thermodynamic topics TEST covers. Besides more examples and a visual tour, you will also find a visual manual for the daemons explaining different buttons and widgets found in the daemons. You will see how a wide range of thermodynamic problems can be visually solved and parametrically studied without the need for a single line of programming.