Transcript Introduction to Engineering Calculations

Introduction to Engineering
Calculations
Module 1
Bioe201 DP
EMERGENCY RESPONSE RECOMMENDATIONS
My Expectation
Cell phone use is restricted in the class. If you
need to use it you can step out without
interrupting the lecture. Thank you for paying
attention
Grace period for late arrival: 7 mins. If you
know that you will be late for some
unavoidable situation, please send me email
Work hard and we will have fun
Text Book
Overview
Module 1 provides motivation for a quantitative engineering
approach and exposure to different bioengineering technologies
and research topics.
Topics:
• Drug Delivery for Parkinson’s disease (mass, moles, mass
fraction, concentration)
• Mars surface condition (temperature, density, saturation)
• Gene delivery (momentum, kinetic energy, current, charge)
• Getting to and life on Mars (force, weight, pressure, heat, work)
• Microsurgical; assistant (flow rates, pressure)
• Victoria falls (rate of momentum, rate of potential energy)
Why Do you Need a Quantitative Approach?
Example: Melanoma (Skin Cancer)
Source: cancer.gov
Physical Variables Units and Dimensions
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Substantial variables
Mass, length, volume, viscosity, and temperature)
Need precise physical standard for measurements
Units
Natural variables
Units and Dimensions
Character of a material
Qualitative – Identify the nature and type of the character (e.g.
mass, length, time), which is called dimension.
Quantitative – Requires both number and standard to describe.
Dimensions are properties that can be measured such
as length, time, mass, temperature, or calculated by
multiplying or dividing other dimensions, such as
velocity (length/time)
• Units are means of expressing the dimensions such as
feet or meter for length, hours/seconds for time.
• Every valid equation must be dimensionally
homogeneous: that is, all additive terms on both sides
of the equation must have the same unit.
SI System and British System
• The International System of Units (Le
Système international d'unités)
• modern form of The International System
of Units (Le Système international d'unités)
• modern form of the metric system
• most widely used system of measurement
• comprises a coherent system of units of
measurement built around seven base
units, 22 named and an indeterminate
number of unnamed coherent derived
units, and a set of prefixes that act as
decimal-based multipliers.
Common Systems of Units
Derived SI Units
Systems of Dimensions
• Mass [M], Length [L], Time [T]
• Force [F], Length [L], Time [T]
Systems of Units
MLT
• SI (kg, m, s)
FLT
• British Gravitational (lbf, ft, s)
CONVERSION OF UNITS
• A measured quantity can be expressed in terms of
any units having the appropriate Dimension
• To convert a quantity expressed in terms of one
unit to equivalent in terms of another unit, multiply
the given quantity by the conversion factor
Density
• For solids and liquid vary slightly with T
• For solutions, function of both conc. and T
• Gas densities are highly dependent on T and P
SYSTEMS OF UNITS
• Components of a system of units:
– Base units - units for the dimensions of mass,
length, time, temperature, electrical current, and
light intensity.
– Derived units - units that are obtained in one or
two ways;
• By multiplying and dividing base units also referred to
as compound units
Example: ft /min (velocity), cm2(area), kg . m/s2 (force)
SI and American engineering system units.
Force and Weight
• Be sure you understand the difference
between lbf and lbm
• Be sure you understand the difference
between the physical constant g, and the
conversion factor gc.
Force, Weight and Mass
Force is proportional to product of mass and
acceleration and is defined using derived units to equal the
natural units;
1 Newton (N) = 1 kg.m/s2
1 dyne = 1 g.cm/s2
1 Ibf = 32.174 Ibm.ft/s2
• Weight of an object is force exerted on the object by
gravitational attraction of the earth i.e. force of gravity, g.
• Conversion: from a derived force unit to a natural unit, a
conversion factor, gc must be used.
• A ratio of gravitational acceleration, g to gc may be used
for most conversions between mass and weight.
Size Scales
Typical Pressure Values
• Best laboratory vacuum 1pPa
• Additional pressure on ear drum caused by noise at
a rock concert 10 Pa
• Pressure exerted by a penny lysing flat on a table
85Pa
• Mars surface air pressure 1 kPa
• Earth atmos pressure, 10-km alt 26 kPa
• Earth atmos pressure, sea level 101.3 kPa
• Blood pressure 110 kPa
• Pressure inside car tire 320 kPa
• Household water pressure 350 kPa
• Ballet dancer on one foot 2MPa
• Deep trenches in the Pacific Ocean 100 MPa
19
Temperature Scale
Source: quoteaddicts.com
Dimensionless Analysis
• Manipulate equations to solve for unknown variables.
• Help simplify complex bioengineering problems into a smaller,
comprehensible basic tasks
• Manipulate units in a problem
Numerical values and their corresponding units may be
added or subtracted only if the units are the same
10m- 8m = 2m, however, 10m-8s=?
Multiplications and division always combine numerical
values and their corresponding units.
(10 N) (5 m) = 50 N.m ; (10 cm/s)/8cm=1.25/s
Dimensionless Analysis
• In a properly constructed equation, general relationship
between the physical variables must be dimensionally
homogeneous
i.e. the dimensions that are added or subtracted must be
the same, and the dimensions of the RHS equation must be the
same as LHS equation
Example 1:
1
1
𝜇 = 𝑀/4𝜋ℎ ( 2 − 2)
𝑅𝑜
𝑅𝑖
Margules equation
𝜇= fluid viscosity
 = No of radians /sec (T-1)= s-1
Both sides of the equation has dimensions= L-1MT-1
Example 2:
ln c/c0 = 𝜇𝑡
Expression of cell growth
𝑐= cell conc at time t;
𝑐𝑜= initial cell concentration
𝜇= specific growth rate
Dimensionless!
Reynolds number
A vortex street around a cylinder. This occurs around cylinders, for any fluid, cylinder size
and fluid speed, provided that there is a Reynolds number of between ~40 and 103.
The Reynolds number is the dimensionless quantity that
occurs frequently in the analysis of the flow of fluids.
For flow in pipes it is defined as DVr/m, where D is the
pipe diameter, V is the fluid velocity, r is the fluid
density, and m is the fluid viscosity.
doi:10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2.
Qualitative behaviors
of fluid flow over a
cylinder depends to a
large extent on
Reynolds number;
similar flow patterns
often appear when the
shape and Reynolds
number is matched,
although other
parameters like
surface roughness
have a big effect
Technologies
Drug delivery for Parkinson’s
Gene delivery
Microsurgical assistant device
Surface condition on Mars
Life on Mars
Niagara Falls
Drug delivery for Parkinson’s
Mass
Moles
Mass fraction
Concentration
https://sites.google.com/site/activecarephysiotherapyclinic/parkinsons-disease
Biological Barriers
Human barriers
Skin
Mucosa
External barriers
DRUG
DRUG
Cellular Delivery
PROBE
PROBE
En route barriers
Cellular barriers
Endosomal/lysosomal
degradation
Blood
Extracellular matrix
Inefficient translocation
to the targeted sub-cellular organelles
Common Routes of Drug Administration
Human Barrier (Errors)
First Pass Mechanism
Metabolism occurs during the absorption process. The fraction of the initial dose
appearing in the portal vein is the fraction absorbed, and the fraction reaching the blood
circulation after the first-pass through the liver defines the bioavailability of the drug.
Blood Brain Barrier (BBB)
•Blood and brain junction, endothelial
cells are tightly stitched together
• Composed of smaller subunits, e.g.
biochemical dimers, transmembrane
proteins, occludin, claudins, junctional
adhesion molecule (JAM), ZO-1 protein
• Crossing BBB: disruption by
osmotic means; biochemically by the
use of vasoactive substances such
as bradykinin; localized exposure
to high-intensity focused ultrasound
(HIFU)
• Pore size upper limit ~12 nm
(malignant glioma), Mw= 500 Da
• Polyethylenglycol, peptides…..
A cortical microvessel
stained for blood-brain
barrier protein ZO-1
Going to Mars
Temperature, density, saturation/humidity, ……
Gene delivery
Momentum
Kinetic energy
Current
Charge
The concept is simple: if a mutated gene is causing a problem, replace
or supplement it with a new, accurate copy. In theory, such a strategy
could not just treat, but cure countless human genetic diseases.
https://sites.google.com/site/activecarephysiotherapyclinic/parkinsons-disease
Gene Delivery
http://gene-therapy.yolasite.com/process.php
Gene Gun
• Biolistic particle delivery
system, originally designed
for plant transformation
• Device for injecting cells
with genetic information.
The
payload
is
an
elemental particle of a
heavy metal coated with
plasmid DNA.
• This technique is often
simply referred to as bioballistics or bio-listics.