Chemical Engineering - Enterprise

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Oct 24, 2013 (3 years and 7 months ago)

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Chemical Engineering
DEMos

& the Medical
microDevice

Engineering
Research Laboratory

Dr. Adrienne Minerick

ITEST High School Enterprise
summer teachers'
workshop

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http://consiliencejournal.readux.org/wp
-
content/uploads/2008/02/curtis1.png

Lab on a Chip Device

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Medical Laboratory

Future Microdevices

Time

Days

Minutes

Cost

Sample
Volume

$$$

Milliliter

$

< Drop


Variability in testing


Technician error


False positives / negatives

Reliability

Sia et al., 2003,
Electrophoresis
Tudos et al. 2001
, Lab on a Chip
Kim et al. 2006,

Lab on a Chip



Point of care test



Device variability



Reproducible and rapid



Operational simplicity

Lab on a Chip Device (2)

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4

www.ims.tnw.utwente.nl

www.niherst.gov.tt

Fabrication of Microdevices

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What are
students
currently interested in?

Cell Phones

Computers

Music

Sports

Gaming
Stations

Fishing

Food

Cosmetics

Fashion

Environment

Scientists & Engineers are the
basis for all of these!!

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Chemical Engineers make the world
a better place….



Civil engineers build bridges, water / sewage conduits


Chemical engineers make the concrete &
engineered it to be stronger, less corrosion resistant


Design bioremediation processes for wastewater
treatment (now even making biofuels from
wastewater)



Mechanical engineers design better engines


Chemical Engineers design synthetic fuels for
better performance, life.



Electrical engineers design better computer chips


Chemical engineers do the
microfabrication

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Chemical Engineers even have
an impact on health care…



Students in my lab (Medical micro
-
Device Engineering
Research Laboratory) are designing and testing
microdevices

to analyze blood samples for point of care
medical diagnostics.

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M.D.


ERL Devices

PDMS
Channels

Si wafer



Master


A

F

E

D

C

B

A

F

E

D

C

B

A

F

E

D

C

B

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What is Chemical Engineering?

Modern society depends extensively on
chemical engineers
-

they help manage
resources, protect the environment, and
control health and safety procedures while
developing the processes to make products
we desire or depend on.

Raw
materials

Valuable
products

Apply chemistry, physics, math, &
biology to solve real world issues

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Average Annual Earnings for College
Graduates and Non
-
Graduates

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Engineers / Scientists make more than
other majors & they also have a very
positive impact on society

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Timeline

Birth

~75

Death

15

College

$30,000

$63,000

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Chemical Engineering @
Tech

Considering graduate school?


Professors hire students in research
laboratories


NSF sponsored Research Experience for
Undergraduates (REU)


Undergraduate Research

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Contact me at:

Adrienne
Minerick

minerick@mtu.edu


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Subtopics of Chemical Engineering


Analytical Methods & Products


Biomedical


Biotechnology


Ceramics


Chemical Producers and Suppliers


Databases


Education Resources


Electrochemical


Energy, Conservation and Efficiency


Engineering and Construction


Environment


Fluid Mechanics


Forest Products


Heat Transfer


Law School


Mass Transfer


Materials


Medical field


Nuclear


Particle Technology


Petrochemicals and Fuels


Polymers


Reactions


Process Control


Process Design


Process Modeling


Safety and Hazards


Software Products and Suppliers


Standards


Statistics and Experimental Design


Teaching Topics and Resources


Water Technology

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Desktop Experiment Modules (
DEMo

s)


DEMo

s are versatile, inexpensive, and portable
experiments


On student desks throughout a classroom.


Superior to instructor led demonstrations

1.
Each student can closely examine and manipulate
the apparatus,

2.
Student teams can progress through experiment
discovery at their own learning pace, and

3.
All learning styles are stimulated to maximize
understanding of important fundamental
concepts.


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Target Audiences


Introduction to Chemical Engineering Courses


Separations Classes


Analysis Class
(data collection, analysis, report writing)


Mass or Heat Transport Classes


Unit Operations


Outreach / Recruiting / Retention


Engage the students


Make concepts come alive


Recruit and retain a broader


spectrum of students with


new techniques.

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Electrophoresis is a separation tool for biological
species (DNA, RNA, proteins, cells)




Formation of ionic compounds, ionic radii, ionic strength


Electrolysis reactions


pH changes / indicators


Electrophoretic mobility

+

-

e
-

e
-

-

+

Anode

Anode

Cathode

Cathode

Seasoned
DEMo
: Charged up on Electrophoresis

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Advisory Board
-

26
April 07

Seasoned
DEMo
: Brewing with Bioreactors

Demonstrate fermentation
(microorganisms conversion of
food source to product)


Batch vs. Continuous Process


Mass Balances (global)


Reaction vessel


Population life cycle


Reaction of sugar to CO
2


Necessity for separations

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Learning tool that is versatile, fairly inexpensive, and portable
such that it can be positioned on student desks


Superior to instructor demonstrations because


each student can closely examine and manipulate the apparatus,


student teams can progress through experiment discovery at their
own learning pace, and


all learning styles are stimulated to maximize understanding of
important fundamental concepts.


Engage the students to make concepts come alive


Recruiting to engineering & change the paradigm that
engineering is impossibly difficult


Diversity in undergraduate programs helps feed diversity in graduate
programs.


Can recruit & retain a broader spectrum of students with new
techniques.

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For each team of 2
students

Cost per item

Coffee Cup Warmer

$10

CPU Heat Sink with Fan

$7

1.5 inch Rods of Al, Cu, Steel

Al ($1.25/inch),

Cu ($7/inch),

Steel

($1/inch)

Blocks of wood,
styrofoam
,

fire brick, drywall,
glass (from local hardware store)

Negligible cost (ask for
broken pieces)

Fisher Infrared Thermometer (res is 0.1
o
C,

acc is
±
1
o
C)

$30

Heat Sink Compound (
Radioshack
)

$3

9 Volt batteries

$0.75

Battery leads

(
Radioshack
)

$0.20

TOTAL:

$60 per station

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One dimensional conduction


Thermal conductivity


One dimensional conduction in composite systems


Thermal contact resistance


Transient heat generation


Steady state heat generation


Heat transfer from extended surfaces (fins)


Convection


Radiation

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This concept is illustrated by the IR thermometers utilized in
the experiment.


Use blackbody radiation emitted from objects to determine
temperature.


Measure amount of infrared energy emitted by the object


Uses an assumed (constant) emissivity,
ε
=1


ASEE

2009

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This step is necessary at the beginning of each experiment and can be used to remind
students that processes are not always at steady state.

Experimental Procedure:


Take initial temperature reading of plate warmer before turned on and record its initial
temperature at time 0.


Turn on the plate warmer and begin stop watch at the same time.

y = 0.2646x + 22.3

y = 0.1869x + 24.5

0
20
40
60
80
100
120
140
160
180
0
200
400
600
800
Temperature (
o
C)

Time (seconds)

Transient Generation #1
Transient Generation #2

At 15
-
second intervals, take a
temperature reading of the
plate warmer using the infrared
thermometer. Make sure to
measure at the same location
for each reading.


Continue to take readings until
the mug warmer temperature
is constant for 45 seconds and
reaches steady state.


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Spatial variations not considered so heat diffusion equation is:




Assuming constant generation,
q
, the solution is:



Using the initial condition that the temperature of the mug warmer was initially
at 22.3
o
C, it is possible to solve for the constant of integration.



Compared to the data collected



Take apart mug warmers


the plate is primarily aluminum, which has a
density of and a heat capacity of .



Heat generation is


Q: Having assumed constant heat generation, why is the data curved?

.

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Determine by performing an energy balance at the surface

Energy generated in the plate = energy
convected

away from the plate



For relatively still air, measure ambient air Temperature, and thickness of the
plate:



Or heat flux is:



Current calculated from information on the mug warmer unit



Obtain electrical resistance (and compare to tabulated values)


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Mug warmer is a heat source on a wall of a material



1D
conduction illustrated at student’s desks


Demonstrate thermal conductivity of different materials

Material

Thermal
Conductivity (


)

Polystyrene

(R
-
12
)

0.027

Softwood

(Fir)

0.12

Plaster

board

0.17

Polycarbonate

0.21

Firebrick

1.0

High

Density

Carbon

Steel

60.5

Aluminum

Alloy

2024

177

Copper

401


Turn
on mug warmer
with
block

on
top and
allow
system to heat
up for 15 minutes.


Check temperature three
times at
30
-
second intervals to ensure the
system has reached steady state.


Note temperature
at the surface
of the mug warmer

may
be
greater than

when
exposed only
to
convection.


Replace
with new blocks of
material allowing it to equilibrate
between temperature readings
.

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Heat diffusion equation for one dimensional, steady state conduction with
constant thermal conductivity is



General solution is:


Boundary conditions determined from student’s experiment. Example uses
polycarbonate block 1 cm thick.


and


Particular solution in symbolic and numeric form:



Obtain a different temperature profile for each material.


Use Fourier’s Law to determine the conduction heat transfer rate.


and




Can use heat flux from SS heat generation experiment too.

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Heat up plate warmer to reach steady state


Place CPU passive heat sink on the mug warmer and start timer


Measure T at two locations


Repeat with the fan on [data from Christine
Lottes

and Doug Hall]

20
22
24
26
28
30
32
34
36
38
40
0
100
200
300
400
500
Temperature (
o
C)

Time (sec)

Comparison of Natural vs. Forced Convection

Location 1 (no fan)
Location 2 (no fan)
Location 1 (fan)
Location 2 (fan)
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Heat up plate warmer to reach steady state


Place CPU passive heat sink on the mug warmer and start timer


Record until system reaches SS, turn on fan [data from Rachel Blair and
Kaneb

Jamison]

20
22
24
26
28
30
32
34
36
38
40
0
100
200
300
400
500
600
Temperature (
°
C)

Time (sec)

Heat Exchanger's Temperature Change with the Fan Off and On

Heat Exchanger (fan on)
Heat Exchanger (fan off)
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Time dependent fin temperature expressions are not covered in undergraduate
heat transfer courses.


Ideal to determine T as a function of position


not possible with the IR
thermometers


System used as an illustrative visual aid when discussing heat transfer from fins


Most CPU heat sink fins are of uniform cross
-
sectional area.


Tip experiences convective heat transfer (boundary condition)


steady state, position dependent temperature distribution is



Steady state fin heat transfer rate is




where and

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Diffusion vs. Convective Mass Transfer


Molecular Diffusion:



: D=10
-
7
cm
2
/s


Diffusional

Time Scale:





h=width of channel



Convection


Use
Peclet


number to
compare to diffusion




Estimate Velocity, U




Calculate
Pe

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Human Erythrocytes


ABO Typing System:
Landsteinner

in 1900 [1]


2 main antigens


A: N
-
acetyl
-
D
-
galactosamine


B: N
-
acetyl
-
D
-
glucosamine

7microns

2microns

O
2

CO
2

“Red Blood Cells”
http:
//www
.academic.marist.edu/~
jzmz/HematologyI
/Intr
o8.html


Rhesus Factor:


Presence = positive blood type (Absence = negative)


~85%

of population exhibits Rhesus Factor [2]


~1.5

million antigens per cell [3]

[1
] Landsteiner, K. 1900

[2]
Dailey.
Blood,
1998

[3]
Minerick, A.R.
AIChE

Journal.

2008.

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Antigen Structure

Minerick,
AIChE

J, 2008

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Foundation


Load an unknown blood sample and identify types based on deflection to
the
channel


AC
-
DEP
-

> 95 % confidence in distinguishing O
+


Hypothesis


DC
-
DEP
-

distinguish blood types based on deflection from an insulating
obstacle, into a streamline and out to the channels


Impact


Fast, inexpensive, reliable, accurate, and point of care device which could
be used in emergency situations, accidents, wars, etc


Hypothesized
outlet streams

Bifurcation point

Keshavamurthy et al., 2008,
proceedings of NSTI
-
Nanotech

Premise
-

DC Separation of Blood Cells

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Buffer Conductivity= 50 mS/cm; 10 X magnification

A
-
: 5 min run @ 0.25
s

interval

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Experimental Setup


1kHz Experiments

Dilute
blood with
PBS

Load into
microdevice

Hook up to
Signal
Generator

Video
Images
from
Zeiss


Every 15
sec for 15
min

Automeasu
-
rement

Program

Overall
picture of
rupturing

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For each image, the fraction of ruptured cells
was calculated from raw data showing the
amount of cells present in the field of view



-0.2
0
0.2
0.4
0.6
0.8
1
0
100
200
300
400
500
600
700
800
900
Fraction of Ruptured Cells

Time (sec)

Time Dependent Rupturing

Time Dependent Rupturing

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Natural pH Gradients

Macounova
,
et al. Anal. Chem.
72

(2000) 3745
-
3751

Anode
rxn
:

Cathode
rxn
:

Finite number of ions in microchannels allows concentration gradients via mass transfer

Fused silica used in many
applications

Silanol

groups:



O
-
H dissociation impacts EOF
via

-
potential

Charge distribution depends on
environment (i.e. pH)

Minerick
,
et al. Electrophoresis
24

(2003) 3703
-
3717

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pH gradients in
microchannels

can affect
transport


Conductivity affects Debye length and EOF


Complicates prediction of system behavior


0
.
25



0
.
75

1
.
25



1
.
75

2
.
25

2
.
75

cm


+

-

+

-

Fluorescence of CI
-
Nerf along capillary was
measured.
Intensity increase indicated a pH
increase of 4.5

Minerick
,
et al. Electrophoresis

24

(2003) 3703
-
3717

Reproduced with permission:

Minerick
,
et al.

"Development of a pH Gradient in a 20
-
micron
Capillary Microdevice," AES Annual Conference; 2002,
Indianapolis, Indiana.

Previous Studies

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Paper
microfluidics


Fluid flow driven by capillary action


of water in paper
-
no power required


Channels can be defined by drawing on
paper with wax or a Sharpie marker


Lengths of the channel dictate timing of flow
into different elements


Hundreds of prototypes can be printed at
once with a simple printer

Urine analysis: Brown indicates glucose, blue
indicates protein. Sample is wicked from the
base of the tree.

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ACTIVITY: Hydrolysis
Reactions Driven by
Electric Fields Lead to pH
Changes

ANODE (oxidation):


CATHODE (reduction):

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Hydrolysis in paper

Experimental procedure:


Place a drop of water on strip of pH paper


Wipe off excess fluid with paper towel


Attach lead to 9V battery


Touch the leads on the paper 2 cm apart


Observe pH change indicated by color change


Remove leads from battery


Touch the battery poles on the pH paper


Observe pH change indicated by color change

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COMSOL simulation of pH rise due to OH
-

generated by hydrolysis in a 2 cm channel. x
-
axis:
Position in channel, y
-
axis: pH

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Kaela

Leonard

Dr.
Soumya

Srivastava

Aytug

Gencoglu

Chung
Ja

Yang

Angela
Dapolite

Sean Duke

Courtney
Lentowich

Dr. Adrienne
Minerick

minerick@mtu.edu

www.MDERL.org

All work conducted in a certified
Biosafety

level II (BSL II) laboratory with the approval of
Institutional
Biosafety

Committee (IBC) and
Institute Review Board for the protection of
human subjects (IRB)