TEST is a visual environment, and not another programming language, designed to integrate computational solution to learning and practicing thermodynamics.  The smart environment is created by a web of carefully designed HTML pages with schematics, equations, pedagogic explanations and embedded smart thermodynamic calculators, affectionately called the daemons. the word daemon is not meant to scare away students of thermodynamics; it is more like a genie, a cross between Maxwell's thermodynamic demon and the robust background applications that lurk behind the Unix operating system. 

Built on an intuitive graphical interface - the first of a kind - the daemons can be used to perform numerical experiments to understand thermodynamic properties, solve complete problems,  pursue any conceivable what-if scenario without any additional overhead, create solution report, plot thermodynamic charts, and create codes that can be shared for reproducing the solution or remote collaboration. As users from around the world suggest changes, TEST is continually evolving; check on line for the latest edition.

Briefly here is how TEST works. A problem solving session begins with the most general system. The user starts to simplify the system by selecting an appropriate branch, (open vs. closed, for instance) that best describes the problem, from an exhaustive list of choices offered by the simplification  table. As more specificity is added to the system (steady vs. unsteady,  for instance), the changes in the system schematic and governing equations (mass, energy and entropy balance equations) are displayed on request. Finally, the user is asked to idealize, i.e., select a model (ideal gas vs. phase-change model, for instance) for the working substance. At that point,  the daemon (see Fig. 1), aware of material properties and governing equations for this particular problem is launched. (Takes about 10-60 seconds over the Internet and less than 5 seconds when locally installed). 
 

The visual
State Calculator.
 
 
 
 
 
 
 
 

Use of algebraic expressions.
 
 
 
 
 

The Analysis Panels.
 
 
 
 
 
 
 
 
 

Use of 'Excel' type algebraic expressions makes it easy to construct related states (for instance, entropy for state-2, isentropic to state-1, can be entered as '=s1'). Units are appropriately interpreted in such relations. If T1 is entered in deg-F and T2 is expressed in deg-C, the expression T2=T1+10 is interpreted as T2 (deg-C) = T1(deg-F)+10(deg-C).

The calculated states are loaded onto the problem specific Analysis panel as the inlet or exit (initial or final) states for a device (or a process). The known device (or process) variables such as heat and work transfer are entered. With the click of a button, the mass, energy and entropy balance equations, displayed in their customized form on the Analysis panel, are solved, information is exchanged between the Analysis and  States panels, and all variables are updated. A separate panel is used for Exergy Analysis.  In the analysis of cycles, multiple devices (or processes) are loaded into the Cycle panel, where the cycle variables are calculated after the completion of device (or process) analyses. 
 

A visual design tool to 
conduct what-if studies.
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Regenerating the visual solution with TEST-Codes.
 
 
 
 
 
 
 
 
 

Use TEST as a numerical laboratory to understand properties.
 
 
 
 
 
 

TEST is platform independent and incapable of crashing your system.
 
 
 
 
 
 
 
 
 
 

Thermodynamics - anywhere, anytime!
 

But the fun begins after you solve a problem. Because all the variables are visually exposed, you can study any conceivable what-if scenario by simply changing one or more variables and updating all calculations by a single click (as in a spreadsheet). A simple problem of finding the mass of water vapor in a room can be converted to a humidifier design exercise by studying the water requirement to achieve a desired relative humidity. A study of how condenser pressure affects the thermal efficiency of a Rankine cycle can be instantly turned around to see the effect of boiler pressure, or the turbine efficiency, or the maximum temperature - all without a single line of programming. This is especially useful for educators who want to back up theoretical conclusions with a quick in-your-face confirmation right in the classroom.

TEST produces a complete solution rather than a narrow answer (for instance, in a problem to determine exit velocity in a nozzle, the nozzle exit area is also calculated) providing insight to a problem. With the click of a button the visual solution generates detailed printer-friendly output, spreadsheet-friendly property table and a set of instructions called the TEST-Codes that can be used  to jump-start the visual solution. Using TEST-Codes students can collaborate on a solution  remotely by emailing partial solutions to each other.

TEST can be used as a numerical laboratory to understand the behavior of thermodynamic properties. A  plot of entropy vs. temperature at a particular pressure generated for nitrogen, for instance, can be quickly repeated by a single click after a new pressure is entered. The TEST-Code produced by the visual solution can be copied to a different material model and the study can be repeated in minutes to compare different models - perfect gas, ideal gas, real gas or phase-change - that carry nitrogen in its database. 

TEST does not require any installation, it is simply copied to your hard disk or a web server. The daemons, written in 100% Java, are browsed using a Java enabled browser such as IE or Netscape Navigator. As a result TEST can run on any platform (Windows, Unix, Linux, or MacOS) capable of running a Java enabled browser. The inherent protections used by modern browsers shield TEST from crashing your system or passing on a virus. The other side of this security feature is that TEST cannot write to your disk directly. To save the TEST-Codes, you have to copy the code to a word processor (WordPad, for instance) first. 

The Educational version of TEST is freely distributed to educators. Mirroring is encouraged so that only the latest version is accessed by everyone. A large number of universities around the world have installed TEST and the user base continues to grow. It is very possible that no matter where you travel in the world, you will find TEST anywhere anytime as long as you have an access to a web browser. 

The Navigation section describes two approaches - a systematic approach for the beginner and a short-cut for the advanced user - to get to a desired page.  The Approach section discusses the questions that must be answered in order to decide on the right daemon. The Daemons  section presents a brief background discussions (Manual) and hands-on examples (Applications) on ten categories of daemons. Finally the TEST-Codes section covers the rules and syntax of TEST-Codes for instantly regenerating a visual solution.

Several students and colleagues have helped me throughout the development of TEST. Wonchul Jung, Chuck Parme, Shan Liang, Matt King, Jeff West, Guy Fujiwara and Albert Nguyen are some of the students I must single out. I am indebted to my colleagues Professor Roger Whitney, Bob Cademy, Mark Boyns and Andrew Scherpbier who got me interested in Java, and to Chris Paolini  for managing the web servers. Special credits are due to Ms. Tanuka Bhattacharjee who designed the highlighting colors used in the daemons. The profuse use of blue and green, however, was influenced by the color-affinity of my children Robi, Sarah and Neil who have lost a lot of play-time with their 'Baba' during the long period of software development. Finally, I must express my gratitude for Kyoung-Hee (Keya) Bhattacharjee for helping me with the data structure and program design, and for being my wife.

And last but not the least, I thank Sun Microsystems for supporting part of this project through an Academic Grant and, more importantly, for inventing Java.

Navigation

Approach

Daemons

TEST-Code