6 Pressure, Flow, Energy, BP, Vaporization, Heat, & Temp Flashcards
Force
That which changes or tends to change the state of rest or motion of an object Push or pull on an object Vector - direction and magnitude Type of energy = Mass (kg) · Acceleration (m/s^2 ) = (kg · m)/s^2 Newtons (N) (g · cm)/s^2 = Dyne SVR/PVR
Work
Measurement of the amount of change a force produces when it acts on an object/body = Force · Distance (displacement) = (Mass · Acceleration) · Distance = kg · (m/s^2 ) · m = Newton · meters = (kg 〖· m〗^2 )/s^2 = 1 Joule (J)
Total Energy
Kinetic + Potential energy Internal energy of system = sum potential and kinetic energy in the particles w/in the system Energy - the currency of force Capacity to do work (measured in ft lbs) Measured in Joules
Kinetic Energy
= (Mass ·(Velocity)^2 )/2 OR Mass · (Velocity)^2 · 0.5
Energy of motion - energy a mass possesses by being in motion
Measured in Joules
Potential Energy
= Mass · 9.8 m/s^2 · Height = kg · 9.8 m/s^2 · m = (kg ·〖 m〗^2 )/s^2 = Joule Energy of height (gravity impact) *stored for later use* Example: Rollercoaster Measured in Joules
Power
= Work/Time
= Joules/Seconds
= Watts
Reynolds Number
Predicts laminar or turbulent flow (Inertial Forces)/(Cohesive Forces) Re < 2,000 Laminar Flow Re > 4,000 Turbulent Flow (↑ Resistance) Re 2,000−4,000 Transitional Re = (velocity ⋅ diameter ⋅ density)/viscosity Does not consider or predict resistance
Resistance/Flow/Pressure
Q = ∆P/R
∆P = Q x R
R = ∆P/Q
Flow - volume gas or liquid passing through cross-sectional area over unit of time (length/seconds) produced by pressure gradient application
Pressure
= Force/Area ↑ surface area ↓ pressure ↓ area ↑ pressure Density directly proportional ↑ density ↑ pressure Administering drug via 18G vs. 24G IV
Dalton’s Law
Partial pressure - exerted by single gas component of mixture
P1 + P2 + P3 + PN = Total pressure
Atmospheric Pressure Units
760mmHg 760 Torr 14.7 PSI 1,000cmH2O 100 kPa 1 bar 33 ftH2O
Pressure at Altitude
Sea level = 1 Atmosphere 10,000ft = 0.66 (2/3) 1 Atmos 20,000 = 0.5 (1/2) 1 Atmos NOT linear relationship b/w altitude & pressure 60,000 H2O boils 37°C Underwater: 33ft H2O = 2 Atmos 66ft H2O = 3 Atmos 99ft H2O = 4 Atmos H2O much more dense than air
Acceleration
m/s^2
s^2 = traveling at specific rate m/s per second
Rate
m/s
Cruise control - constant mph
Pascal’s Law
External pressure transmitter equally throughout = homogenous
Pressure transmitted equally therefore able to read via gauge to measure pressure w/in
Not affected by gravity
Atmospheric Gas Composition & Pressure
Dry air N2 79% 594mmHg O2 21% 159mmHg (1% trace inert gases) Water vapor 47mmHg
PSIG
Pounds per square inch gauge
Set to read 1 atm (14.7psi or 760mmHg) less than absolute pressure
Indicates usable/useful volume of gas in container
Tank works via negative pressure system, once equilibrates w/ atmosphere then gas will no longer be able to flow out
“Empty” tank not truly empty
PSIA
Absolute pounds per square inch
Set to read the TOTAL about gas present in container
Cannot get out unless suction out remainder
Absolute Pressure
Gauge pressure + Atmospheric pressure
Total amount gas present in the container
Laminar Flow
Stronger intermolecular and cohesive forces = more likely to have laminar flow
↑ IMF ↑ viscosity
VISCOSITY keeps molecules “in-line”
“Sheets” of molecules
Flow α 1/Viscosity
↑ viscosity ↓ flow
Viscosity determinant of gas flow when flow is laminar
Turbulent Flow
Velocity, diameter, & density - forces that tend to disrupt cohesive forces therefore molecules move “out of line”
Flow α 1/√Density
↑ density ↓ flow
Density determinant of gas flow when flow is turbulent
Influences probability that interactions b/w fluid molecules will occur - ↑ density ↑ molecules per unit area ↑ chance of molecular collisions ↑ drag ↑ resistance ↓ flow
Boiling Point
Temperature at which the vapor pressure of liquid equals ambient pressure
Entirety of liquid enters the gas phase
↑ ambient pressure ↑ BP
Ex: Desflurane ↑ temperature
