Microsoft Word - Cengel and Boles TOC _2-03-05_.doc

Glossary

to accompany

Thermodynamics: An Engineering Approach, 5th edition

by Yunus A. Çengel and Michael A. Boles

12

Cycle is a process, or series of processes, that allows a system to undergo state changes

and returns the system to the initial state at the end of the process. That is, for a cycle the

initial and final states are identical.

Cyclic relation of partial derivatives shows that the derivatives of a function of two

variables are related in a cyclic manner by

1

zxy

xyz

yzx

⎛⎞⎛⎞⎛⎞∂∂∂

⎜⎟⎜⎟⎜⎟=−

⎝⎠⎝⎠⎝⎠∂∂∂

Daily calorie needs depends on the nutrition levels of people and will vary greatly with

age, gender, the state of health, the activity level, the body weight, and the composition of

the body as well as other factors.

Dalton’s law of additive pressures states that the pressure of a gas mixture is equal to

the sum of the pressures each gas would exert if it existed alone at the mixture

temperature and volume.

Dead state is the state a system is said to be in when it is in thermodynamic equilibrium

with its environment.

Decrease of exergy principle states the exergy of an isolated system during a process

always decreases or, in the limiting case of a reversible process, remains constant. In

other words, exergy never increases, and it is destroyed during an actual process. For an

isolated system, the decrease in exergy equals exergy destroyed.

Deficiency of air results when the amounts of air are less than the stoichiometric amount.

Deflection angle (see turning angle)

Dehumidifying is the process of removing moisture from atmospheric air.

Density is defined as mass per unit volume.

Derivative of a function f(x) with respect to x represents the rate of change of f with x.

The derivative is equivalent to steepness of a curve at a point as measured by the slope of

a line tangent to the curve at that point.

00

()()

lim lim

xx

df f f x x f x

dx Δ→ x Δ→ x

Δ +Δ −

==

ΔΔ

Derived dimensions (see secondary dimensions)

Detached oblique shock or a bow wave is an oblique shock that has become curved and

detached from the nose of a wedge.