Unit 1 objectives

Define Avogadro's law, Boyle's law, Charles law, Gay-Lussac's Law, and Dalton's law of partial pressures.

Avogadro's Law states that if Equal volumes of gases at the same temperature and pressure, will have the identical number of molecules. Boyle's law states that volume is inversely related to pressure. (P1V1 = P2V2) and temperature is a constant. Charles' law states that volume is directly related to temperature. (V1/T1=V2/T2) and pressure is constant. Gay-Lussac's law states that pressure is directly related to temperature (P1/T1=P2/T2) and volume is constant. Dalton's law states that total pressure of mixed gases equals the sum of the partial pressures of all the component gases. (think about all the gases that make up the atmosphere. It isn't just oxygen, but a mixture of gases. Well, all of those gases are only a fraction of the total atmosphere.) Remember combined gas law equation.... (P1 V1)/T1=(P2 V2)/T2

Explain Poiseuille's law. V ̇=(Δ Pr 4π)/(8 lη)

Explains the relationship between pressure and flow through the bronchial airways. Can be mathematically rearranged to determine flow or determine pressure gradient to move the gas. Flow is directly proportional to P and r4. Flow is inversely proportional to l andη. Flow will decrease in response to decrease P and tube radius. If the radius of a bronchial tube is decreased by half, the flow will decrease 16 fold. Pressure is directly proportional to flow, L and η but inversely proportional to r4. If flow remains constant, and the radius of the tube decreased by half.... The pressure to drive the gas through the airways will need to increase 16 times. The more viscous a fluid, the greater the pressure gradient required to cause it to move through a tube. The resistance of a tube is directly proportional to its length. The pressure must increase in direct proportion to the length of the tube to achieve a given flow.

Define absolute zero temperature.

This is the temperature (Kelvin) in which all motion (kinetic energy) stops, this has never been theoretically proven.

Distinguish between gauge pressure and absolute pressure.

a. Gauge pressure -Zero is the common starting point on most gauges and Zero actually refers to atmospheric pressure (1034 cm H2O or 760 mmHg). When referring to L/min = flow and PSI = pressure b. Absolute pressure is the actual pressure reading. Gauge pressure + 1 ATM would be the absolute pressure. What is the absolute pressure if the pressure manometer (gauge pressure) reads 30 cm H2O? 1034 + 30 = 1064 cm H2O

Compare the Celsius, Fahrenheit, and Kelvin scale of temperature measurement.

a. Kelvin -100º difference between freezing and boiling points. 273ºK freezing, 373ºK boiling, and 0ºK is absolute 0...hasn't been reachable yet. b. Celsius --0ºC is freezing and 100ºC is boiling points. Body temp is 37ºC and Room temp is 25ºC. c. Fahrenheit --32ºF is freezing and 212ºF is boiling point. Body temp is 98.6ºF and Room temp is 77ºF. Most common scale in the medical field is Celsius

Use the Reynolds' number of predict laminar or turbulent flow.

a. Reynold's number is used to predict laminar or turbulent flow. When the Reynold's number is less than 2000, flow will be laminar and if it is greater than 2000, flow will be turbulent. Remember that Reynold's does not have units. b. In respiratory, when the gas flow rate increases, flow may become turbulent. Conversely, an increase in airway size will lower the Reynold's number resulting in laminar flow. c. [NR = V x d x (2r / n)] NR = Reynold's number, V = velocity, d = density, r = radius, and n = viscosity

Compare solids, liquids, and gases.

a. Solids have a 0ºC melting point. Water changes from solid to liquid. Freezing point is b. Liquid has a weaker molecular bond; different liquids are going to have different properties and thus different boiling point. The latent heat of vaporization of a liquid is the energy that is required to vaporize a liquid. c. Gases have the weakest of molecular bonds and lack the restriction to movement, making them more easily compressed or expanded. Molecular water is water that is converted to vapor; it is invisible and exerts a pressure. Particulate water, you can see....(aerosols or fog) »example of sublimation (solid to gas)....Dry ice

Explain the law of continuity.

a. This law is used to describe velocity of a gas through a fixed tube b. Velocity of a fluid moving through a tube varies inversely with the diameter of the tube.....(garden hose)

Explain the use of constant pressure jet mixing and viscous shearing to mix oxygen with ambient room air.

a. This would be the use of Air injectors. Used to increase total gas flow by passing the gas through a nozzle or jet, which acts as an air entrainment port. As the velocity of gas increases, the lateral wall pressure decreases creating negative pressure, which draws room air in. Examples are race cars drafting each other and birds flying in a V formation.

Calculate temperature conversions between Celsius, Fahrenheit, and Kelvin scales.

a. ºC = (ºF - 32) / 1.8 b. ºF = (ºC x 1.8) + 32 c. ºK = ºC + 273

Explain the use of Bernoulli's principle and the Venturi's principle to produce acceleration of gas flow.

a.Bernoulli's law states that, pressure drops progressively along the walls of the tube. Pressure drops through a constriction is even greater. With increased velocity of a gas, there is a decrease lateral wall pressure. So,when a fluid is passing thru a narrow orifice, the velocity increases and lateral wall pressure decreases. b. Venturi's Principle states, using the Bernoulli effect by placing an (air entrainment port) just distal to the narrowing uses Venturi principle to increase total gas flow. As the lateral wall pressure drops, the drop in pressure draws room air in, and thereby increasing the total flow...movement from high to low

Distinguish between laminar and turbulent flow.

a.Laminar flow moves in streams and layers b.Turbulent flow is in random and irregular currents which occur when there is a sharp increase in velocity.