ASCI - The Advanced Simulation and Computing Program (formerly called Accelerated Strategic Computing Initiative, or ASCI) is a supercomputing initiative of the United States government created to help the maintenance of the United States nuclear arsenal after the 1992 moratorium on nuclear testing.

Chaparral - A piece of software, developed here at Sandia National Laboratories, that is used to provide surface-to-surface view factors in a general three dimensional geometry.

Conduction - Heat conduction is the transmission of heat across matter. Heat moves from higher to lower temperatures.

Convection - Convection is the transfer of potential energy, for example heat, by currents within a fluid(note: air is a fluid).

Finite-volume -  A method of approximating the continuum conservation equations that
describe a physical process (which are expressed as partial differential equations, PDEs, in their continuum form) by a coupled set of algebraic equations. The approximation process known as Finite-volume derives these  algebraic equations by dividing space into sub regions (known as control volumes) and applying the conservation principals (or equivalently integrating the PDEs over each volume). Other methods of developing similar algebraic equations are known as Finite-difference and
Finite-element methods. Truchas generally uses the Finite-volume approach to this development, although the other approaches are also employed where they are more efficacious.

Fluid interfaces -  The area where distinct materials meet each other. Fluid interfaces may be between two fluids (such as water and air), between a fluid and a solid (water and ice), or between a fluid and vacuum. These interfaces are often dynamic, changing
their location and configuration over time. A good example of a dynamic interface is filling a glass with water from a faucet. Truchas uses the Volume of Fluid (VOF) method to represent and track fluid interfaces. Truchas is also capable of including the influence
of surface tension forces on the interface motion. These interface forces may be either normal or tangential to the surface, or a mixture of both types. Surface tension forces become important in the example of filling a glass with water from a faucet when the water flows very slowly, forming indiviual droplets of water rather than a coherent stream.

Joule Heating - In electronics, and in physics more broadly, Joule heating or ohmic heating refers to the increase in temperature of a conductor as a result of resistance to an electrical current flowing through it. Also known as induction heating.

Phase Diagram - A graphical representation of emperical data that described the dependence of each phase transition on alloy composition and temperature.

Radiation - The process of emission of energy in the form of waves or particles.

R&D - Research and Development

Surface tensions - Surface tension is an effecct within the surface layer of a liquid that causes that layer to behave as an elastic sheet.  This phenomenon allows insects(such as the water strider) to walk on water.

Time-dependent simulation - Almost all physical processes evolve with time. Time dependent simulation attempts to capture the dynamics of each process by solving equations that describe the changes that occur as time passes. The Truchas approach to solving these equations is to divide time into discrete jumps (called "time steps") and predicting the state of the system under study at the end of each of these intervals. An example of a time dependent simulation might be the progressive heating of a metal frying pan that is placed above a cooktop burner. At first only the flat part of the pan that is directly over the burner will get hot, but over time the entire pan will become hotter through a process known as conduction. Eventually (as you probably know) even the handle will get hot and you may burn your hand if you continue to hold on.

View factor - The apparent size of a piece of surface area as seen from a particular viewpoint expressed as a fraction of the total hemisphere that can be seen from the same point.

Viscosity - The measure of the resistance of a fluid to deform under shear stress.  For example, water has a lower viscosity than vegetable oil and honey which have high visocisities.