FE mechanical
relationship between P1, P2, V1, V2, and k
(P1/P2)=(V2/V1)^k
Equation of state for an ideal gas
(P1v1)/T1=(p2v2)/t2
Molecular weight
(mRT)/(PV)
Prefix M as in Mega
*10^6
Prefix G as in Gega
*10^9
For which type of process is the equation dQ=TdS valid? A)irreversible B)isothermal C)reversible D)isobaric
C) reversible Since the sides are separated by an equal sign, the process must be reversible. For irreversible: dQ<Tds
Otto cycle
Describes the internal combustion engine.
Temper
Description of the amount and type of processing done to a material at the mill, including cold work and thermal treatments
Force of drag equation
F=.5*Coeff of drag*density*velocity^2*area
Standard equation for calculating future worth (F), when given the annual rate of return (I) and the present rate (P).
F=P(1+i)^n
Gibbs phase rule
F=c-p+2 F=intensive degrees of freedom=variance P=# of phases C=components Factors=2+#of components-#phases
What is the origin of the energy conservation equation used in flow systems?
First law of thermodynamics
Work
Force x Distance DeltaPE+deltaKE
Tempering
Heating metal to a precise temperature below the critical point. Often done in air, vacuum or inert atmospheres Used to alter: hardness, ductility, toughness, strength, structural stability
Annealing
Heating steel to a specific temperature and then cooling at a very slow and controlled rate -softens a metal for cold working -improves machinability -enhances electrical conductivity -restores ductility Annealing used for steel but other metals can be subject to solution annealed
Diesel cycle
Reciprocating internal combustion engine
cold working
The plastic deformation of a metal at a temperature below that at which it recrystallizes.
Thermal efficiency of a power cycle
The ratio of useful work output to the supplied input energy
Maximum work obtained from a cycle is dependent on...
The temp of the local environment
Dalton's law of partial pressure
The total pressure of a gas mixture is the sum of the individual gases' partial pressures
Four processes for an Ideal, reversible Carnot cycle
Two isentropic and two isothermal processes
Work hardening/strain hardening
Use of permanent deformation to increase the strength of the metal. Aka cold work
Vector magnitude
Vector length (hypotenuse)
Unit vector
Vector with a magnitude of 1. Sometimes called a direction vector
Carnot cycle
a cyclical process that uses only reversible processes, the adiabatic and isothermal processes
extensive property
a property that depends on the amount of matter in a sample. Ex: mass and volume
isothermal process
a thermodynamic process that takes place at constant temperature
Specific enthalpy
h=u+pv
isentropic
having equal entropy
potential energy
mgh
Thermal efficiency for a Carnot engine formula
n= 1- (Tc/Th)
amorphous
no clearly defined shape or form
second law of thermodynamics
the entropy of the universe is always increasing. Impossible for a sys working in a complete cycle, to, as its sole effect, to transfer heat from a body at a given temp, to a body at a higher temp.
Hot working
when the deformation is carried out above the recrystallization temperature.
Equation for natural frequency
wn= sqrt(k/m)
Pump work equation thermo
wpump= h(in)-h(out) h=u + pv
kinetic energy
.5*m*v^2
Density of water
1 g/cm³ or 1000 kg/m3
Liters to m3
1 m^3=1000 liters
How to find Miller indices
1) Determine intercepts of Facebook 2)take reciprocals of coordinates 3)clear fractions 4) Reduce to lowest terms
Surface area of a sphere
4*pi*r^2
1 psi to pascal
6894.76 pascals
Annuity definition
A fixed sum of money paid each year
Oxidation
Absorption of oxygen. Material loses electrons
Fouling
Accumulation of unwanted material on sold surfaces
intensive property
Aka a bulk property. It is a physical property of a system that does not depend on the systems size or amount of material in the system.
Which cycle is the most efficient? Carnot, Brayton, diesel, otto
Carnot, b/c it is completely reversible
Brayton cycle
Constant pressure heat engine. intake, compression, combustion, and exhaust
Vector curl
Curl is a vector operator that describes a vector field's vorticity (rotation), at a point
Hydraulic diameter equation
Hydraulic D= (X-sectional area)/(wetted perimeter)
Entropy change for an adiabatic and reversible process
Net entropy change=0
Adiabatic
No heat exchange
isentropic process
No heat flow and reversible. Adiabatic process not necessarily reversible.
Units of Reynolds number
None
Period from k and m
Period=2*pi*sqrt(m/k)
Metal changes how when hot worked?
Produces a fine grained product Removes strain hardening Combines of annealing and cold working
1st law of thermodynamics
Q-W=delta U
Relative humidity
Ratio of water vapor pressure to saturation water pressure
Creep
Sometimes called cold flow. The tendency of a solid material to move slowly or deform permanently under the influence of mechanical stresses._
