developing a multisemester interwoven dynamic systems project...

1 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Developing a Multisemester Interwoven Dynamic Systems Project to Foster Learning and Retention of STEM Material

Peter Avitabile, Stephen Pennell, John WhiteMechanical Engineering DepartmentUniversity of Massachusetts Lowell

ASEE Conference – June 2006 – Chicago, Illinois

TIME

FREQUENCY

ACCELEROMETER

IMPACT HAMMER

FORCE GAGEHAMMER TIP

FOURIERTRANSFORM

LVDT

DISPLACEMENT

ACCELERATION

DIGITALANALOG TO

DIGITIAL DATA ACQUISITION

NUMERICAL PROCESSINGINTEGRATION / DIFFERENTIATION

( )i1ii1i

1ii xx2

yyII −++= ++

−

QUANTIZATIONSAMPLINGALIASINGLEAKAGEWINDOWS

DYNAMIC TESTINGPULLS ALL THE

PIECES TOGETHER !!!

TIME

FREQUENCY

X

Y

TRANSDUCERCALIBRATION

REGRESSION ANALYSIS

HAMMER TIP CHARACTERIZATION

FOURIER SERIES & FFT

m

k c

x(t) f(t)

SDOF DYNAMIC

MODEL APPROXIMATION

SYSTEM MODEL

100

10

1

ω/ωn

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

0

-90

-180ω/ω n

)t(fxkdtdxc

dtxdm 2

2

=++

DIFFERENT PULSE SHAPES

)ps(a

)ps(a)s(h *

1

*1

1

1

−+

−=

FREE BODY DIAGRAM& EQUATION OF MOTION

LAPLACE & TRANSFER FUNCTION

tsinem

1)t(h dt

d

ωω

= ζω−

FIRST & SECOND ORDER SYSTEMS

SIGNAL CONDITIONER RISE & SETTLING TIME

2 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

The Problem

Students generally do not understand how basicSTEM (Science, Technology, Engineering and Math) material fits into all of their engineering courses

Relationship of basic material to subsequent courses is unclear to the student.

Practical relevance of the material is not clear.

Students hit the “reset button” after each course not realizing the importance of STEM material

3 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

The Problem

Professor, why didn’t you tell us that the material covered in other courses was going to be really important for the work we need to do in this Dynamic Systems course ?

Student Comment:

Hmmmmm...

Professor Thoughts:

Student views material in a disjointed fashion

Professor clearly sees how pieces fit together

4 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

How to Solve the Problem

A new multisemester interwoven dynamic systems project has been initiated

This is to better integrate the material from differential equations, mathematical methods, laboratory measurements and dynamic systems

This is done across several semesters/courses to help students better understand the relationship of basic STEM material to an ongoing problem

5 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

• Develop a project which spans across several semesters & courses to interweave related STEM material in a coherent fashion – strongly emphasizing the inter-relationship

- Simple RC Circuit- Single SDOF System

Goals & Objectives

Cornerstone of Knowledge

• Suggested for first evaluations• These are generic to all engineering disciplines in that they exemplify 1st and 2nd order systems

6 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

What Needs to be Addressed

• Differential equations & numerical processing• Fourier/Laplace transformations• Instrumentation/signal processing/calibration• Analog & digital data acquisition systems• Time & Frequency data• Impulse response & frequency response• Rise time & settling time

Interwoven, multi-semester problem features:

7 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Comparison of Response of Experimental and Simulink M, C, K System

-0.200

-0.150

-0.100

-0.050

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Time [sec]

LVDT displacement

Simulink generated response

Kari Stevens, 11/03/02

Cantilever Beam

Laser Measurement

Accelerometer

Strain Gage

Micrometer

Comparison of Non-Colocated Accelerometer, Laser and Strain GageApproximations of Tip Displacement of Cantilever

Actual System AddressesReal Measurement Problems

Components of Integrated ProjectNumerical Tools with Attention

to Real Measurements

Filtering IntegratesFirst Order Systems

Experimental Problem Integrates STEM Material

Analytical Tools Required

Mathematical Methods

8 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Scope of the Complete Project

Phase 1 Develop analytically oriented material to address the problems and techniques for solving dynamic system problems. The intent is to provide analytical tools but also address the anticipated problems encountered in a real measurement environment

Phase 2 Develop experimentally oriented acquired data that extends the application of previously identified analytical techniques and addresses measurement issues associated with collecting real world data

Phase 3 Implement materials generated in another discipline and another institution. Modify and enhance of all materials based on feedback

9 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Scope of the Complete Project

Phase 1 Develop analytically oriented material to address the problems and techniques for solving dynamic system problems. The intent is to provide analytical tools but also address the anticipated problems encountered in a real measurement environment

Phase 2 Develop experimentally oriented acquired data that extends the application of previously identified analytical techniques and addresses measurement issues associated with collecting real world data

Phase 3 Implement materials generated in another discipline and another institution. Modify and enhance of all materials based on feedback

10 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Phase 1 Develop analytically oriented material to address the problems and techniques for solving dynamic system problems. The intent is to provide analytical tools but also address the anticipated problems encountered in a real measurement environment

Phase 2 Develop experimentally oriented acquired data that extends the application of previously identified analytical techniques and addresses measurement issues associated with collecting real world data

Phase 3 Implement materials generated in another discipline and another institution. Modify and enhance of all materials based on feedback

Scope of the Complete Project

11 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

A simple mass, spring, dashpot system is used to measure displacement and acceleration

Numerical processing of integration/differential needed to process data

MCK Measurement System

m

k c

x(t) f(t)

12 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

MCK Measurement System

Requires extensive use of a wide variety of differentanalytical tools.Significant numerical data manipulation needed.

• Regression Analysis• Data Cleansing• Integration• Differentiation

13 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

MCK Measurement System

The data acquisition system and transducers are intentionally selected such that the majority of possible errors exist in the data

•Drift•Bias•Offset•Quantization•Noise

Plot of Displacement for a Spring-Mass System

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 0.1 0.2 0.3 0.4 0.5 0.6

Time (sec)

Displ

Displ. Meas.Displ. Calc.

c(inch)

Velocity Comparison

-40

-30

-20

-10

0

10

20

30

40

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5Time (sec)

Velocity(in/sec)

14 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

MCK Measurement System

The students are forced to integrate key STEM material and concepts to solve this problem

• Numericalprocessing

• Filtering• Thinking is required !!!

Displacement Comparison

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

Time (sec)

Dis

plac

emen

t (in

ches

)

Measured DisplacementCalculated Displacement

Displacm ent Comparisons

-0.5

-0.4-0.3

-0.2

-0.10

0.1

0.2

0.30.4

0.5

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8

Time (sec)

Dis

plac

emen

t (in

)

Displacement(LVDT) Displacement(Accleraometer)

Bode Diagram

Frequency (rad/sec)

-40

-30

-20

-10

0From: Input Point To: Output Point

Mag

nitu

de (

dB)

System: proj4_rc_2 I/O: Input Point to Output Point

Frequency (rad/sec): 120 Magnitude (dB): -3.03

100

101

102

103

104

-90

-45

0

Pha

se (

deg)

15 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Several tutorials have been developed related to aspects of dynamic system response evaluation

MATLAB scripts utilizing a simple graphical user interface (GUI) emphasizing the inherent aspects of 1st and 2nd order system response developed

LABVIEW modules were also developed

Voice annotated tutorials being finalized

What Has Been Addressed To Date

16 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Theoretical Aspects of First and Second Order SystemsFirst Order Systems – Modeling Step Response with ODE and

Block DiagramSecond Order Systems – Modeling Step, Impulse, and Initial

Condition Responses with ODE and Block DiagramsMathematical Modeling ConsiderationsSimulink and MATLAB Primer MaterialsMiscellaneous Materials

Some examples are illustrated on the following sheets

What Has Been Addressed To Date

17 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

2nd Order System Initial Condition GUI

User enters M, C, K and natural frequency, critical damping and damping are reported.User can vary the physical parameters with slide bars. The frequency response function magnitude is displayed root locus and time response.

18 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

First Order Low Pass Filter GUI

User enters time constant and sinusoidal frequency. The Bode plot is displayed with the cutoff frequency and the sinusoidal frequency applied. The initial sinusoidal signal and “filtered”time signal are also displayed.

19 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Fourier Series Signal Generation GUI

User enters frequency, amplitude and phase components of a user defined signal to display the resulting signal. The user can also select sample signals such as square, triangle, etc and the pre-determined fouriercoefficients are applied to the user-defined signal. The time signal as well as the corresponding frequency component is displayed.

MATLAB GUI Labview GUI

20 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Virtual Measurement System GUI

User enters M, C, K system. User enters the amount of experimental distortion on the accel. (sensitivity, bias, drift) and displacement LVDT (sensitivity, bias, noise) and the low pass filter characteristics to virtually “simulate” the measurement environment. Data can be exported with ability to select which outputs and what effects are included on the measurement.

21 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Single DOF Complex FRF Plot GUI

User enters M, C, K and natural frequency, critical damping and damping are reported.User can vary the physical parameters with slide bars. The complex frequency response function is displayed simultaneously as real, imaginary, magnitude, phase and nyquist plots.

Start MATLAB GUI

22 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Webpage --- dynsys.uml.edu

Project OverviewTechnical PapersTutorialsOnline AcquisitionDownloadsAcknowledgementsPeople

Tutorials cover a wide assortment of integrated material – both paper tutorials with Matlab and Labview modules with voice annotated multimedia overviews

23 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

COILLEAFEQ kkk += COILLEAFEQ kkk +=

Variable Mass

Variable Damping

Variable StiffnessImpact Force

Initial Displacement

System Characteristics Excitation

m

k c

x

Accelerometer LVDT

Measurement Devices

Online Measurement System

RUBEResponse Under Basic Excitation

24 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

RUBE II

RUBEResponse Under Basic ExcitationRUBE I

Online Measurement System

25 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Online Measurement System

RUBE

26 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Online Measurement System

RUBE

System can be remotely run

Stiffness is changed for each run

Sampling rate can be set

Impact is availableInitial displacements – three inputs

LVDT and accelerometers can be turned on and off as desired

Data saved and captured to browser

27 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Initialize Virtual Initialize Virtual InterfaceInterface

ImpactImpactor Initialor Initial

DisplacementDisplacement

Acquire DataAcquire Data

Cam Switch DepressedCam Switch DepressedShutting off MotorShutting off Motor Start AcquisitionStart Acquisition

Acquire DataAcquire Data

InitialInitialDisplacementDisplacement

Change StiffnessChange Stiffness

Start Start Acquisition Acquisition

Online Measurement System - Sequence

28 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Online Measurement System

RUBEData has different contaminants that distort data

29 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Highest Lowest Percent Change

Percent change of Damped

Natural Frequency

Damping Ratio 0.06 0.03 50% 2.30%Mass .134 slug .115 slug 14% 6.70%

Stiffness 11.5 lbf/in 9.68 lbf/in 16% 8.00%Damped Nat. Freq. 4.5 Hz 5.6 Hz 20% N/A

Online Measurement System Variation

30 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Highest Lowest Percent Change

Percent change of Damped

Natural Frequency

Damping Ratio 0.06 0.03 50% 2.30%Mass .134 slug .115 slug 14% 6.70%

Stiffness 11.5 lbf/in 9.68 lbf/in 16% 8.00%Damped Nat. Freq. 4.5 Hz 5.6 Hz 20% N/A

Online Measurement System Variation

COILLEAFEQ kkk += COILLEAFEQ kkk +=

Variable Mass

Variable Damping

Variable StiffnessSystem Characteristics

31 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

m

k c

x=.14m

=.16k

HzfHz n 7.55.4 <<

m

k c

xm

k c

x=.14m

=.16k

HzfHz n 7.55.4 <<

0.5 1 1.5 2 2.5 3

-0.6

-0.4

-0.2

0

0.2

0.4

No WaterAdded Water

0 0.5 1 1.5 2 2.5 3

-0.6

-0.4

-0.2

0

0.2

0.4

low dam pinghigh dam ping

0.5 1 1 .5 2 2.5 3

-0.6

-0.4

-0.2

0

0.2

0.412 Inch S upports16 Inch S upports

Online Measurement System Variation

32 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Implementation of Materials Generated

Materials implemented at UMASS Lowell in the Mechanical Engineering Department

22.361 Numerical Methods for ME22.302 Mechanical Engineering Lab I22.403 Mechanical Engineering Lab II22.451 Dynamic Systems22.457 Vibrations

as well as in the Mathematics Department92.236 Differential Equations

33 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Implementation of Materials Generated

Materials implemented at UMASS Lowell in the Chemical Engineering Department

10.303 Fluid Mechanics10.315 Unit Operations Lab10.317 Applied Problem Solving Course (MATLAB)10.415 Process and Controls Lab

as well as in the Mathematics Department92.236 Differential Equations

34 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Implementation of Materials Generated

Materials implemented at Michigan Tech in the Mechanical Engineering Department

MEEM3000 Mechanical Laboratory SequenceMEEM3700 VibrationsMEEM4700 ControlsMEEM4701 Experimental Structural Dynamics

35 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Some General Observations

Specific evaluations for all the implemented materials for all the courses were not available at the time of the paper submission.

These will be published in a future ASEE paper.

Some general student’s statements are useful for overall comments that thread a theme through the implementation of this material.

36 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Some General Observations

The integration of the material (threaded as a theme) through the courses helped the student to understand the inter-relationship of material

The MATLAB and LabVIEW GUIs helped to solidify general concepts taught in the prerequisite courses

The hands-on application provides reality

The open-ended project with messy data forced students to take ownership of the problem, sort through the problem and think!

37 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Senior Presentation to Math Students

Differential equations are an important to future course work in upper level courses

Pay attention now – this snowboard is nothing more than a BIG differential equation – you need to know these ODEs to solve these types of problems

38 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Summary

A new multisemester interwoven dynamic systems project was described.

Several tutorials and modules developed were presented.

39 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Summary

The salient feature of the project is that material from various courses such as differential equations, mathematical methods, laboratory measurements and dynamic systems is integrated in a fashion that helps the students understand the need for basic STEM (Science, Technology, Engineering and Mathematics) material.

40 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

This project is partially supported by NSF Engineering Education Division Grant EEC-0314875

Multi-Semester Interwoven Project for Teaching Basic Core STEM Material Critical for Solving Dynamic Systems Problems

Peter Avitabile, John White, Stephen Pennell

Acknowledgements

TIME

FREQUENCY

ACCELEROMETER

IMPACT HAMMER

FORCE GAGEHAMMER TIP

FOURIERTRANSFORM

LVDT

DISPLACEMENT

ACCELERATION

DIGITALANALOG TO

DIGITIAL DATA ACQUISITION

NUMERICAL PROCESSINGINTEGRATION / DIFFERENTIATION

( )i1ii1i

1ii xx2

yyII −++= ++

−

QUANTIZATIONSAMPLINGALIASINGLEAKAGEWINDOWS

DYNAMIC TESTINGPULLS ALL THE

PIECES TOGETHER !!!

TIME

FREQUENCY

X

Y

TRANSDUCERCALIBRATION

REGRESSION ANALYSIS

HAMMER TIP CHARACTERIZATION

FOURIER SERIES & FFT

m

k c

x(t) f(t)

SDOF DYNAMIC

MODEL APPROXIMATION

SYSTEM MODEL

100

10

1

ω/ωn

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

0

-90

-180ω/ω n

)t(fxkdtdxc

dtxdm 2

2

=++

DIFFERENT PULSE SHAPES

)ps(a

)ps(a)s(h *

1

*1

1

1

−+

−=

FREE BODY DIAGRAM& EQUATION OF MOTION

LAPLACE & TRANSFER FUNCTION

tsinem

1)t(h dt

d

ωω

= ζω−

FIRST & SECOND ORDER SYSTEMS

SIGNAL CONDITIONER RISE & SETTLING TIME

41 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

A special thanks to the students who have really been the driving force in making all this happen

Tracy Van Zandt, Nels Wirkkala, Wes Goodman and Jeffrey Hodgkins Mechanical Engineering DepartmentUniversity of Massachusetts Lowell

I could not have done any of this without their dedication and devotion

to making this all happen

I have the pleasure of working with them and having them contribute to this effort

Acknowledgements

42 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

And to the undergraduate studentswho have also participated

Adam Butland, Dana Nicgorski,Aaron Williams, Chris Chipman

Mechanical Engineering DepartmentUniversity of Massachusetts Lowell

This past year have also made significant contributions

to the overall project

I am very happy for theircontinued support and dedication

Acknowledgements

43 Dr. Peter Avitabile, Associate ProfessorMechanical Engineering DepartmentMultisemester Interwoven Dynamic Systems Project

Developing a Multisemester Interwoven Dynamic Systems Project to Foster Learning and Retention of STEM Material

Peter Avitabile, Stephen Pennell, John WhiteMechanical Engineering DepartmentUniversity of Massachusetts Lowell

TIME

FREQUENCY

ACCELEROMETER

IMPACT HAMMER

FORCE GAGEHAMMER TIP

FOURIERTRANSFORM

LVDT

DISPLACEMENT

ACCELERATION

DIGITALANALOG TO

DIGITIAL DATA ACQUISITION

NUMERICAL PROCESSINGINTEGRATION / DIFFERENTIATION

( )i1ii1i

1ii xx2

yyII −++= ++

−

QUANTIZATIONSAMPLINGALIASINGLEAKAGEWINDOWS

DYNAMIC TESTINGPULLS ALL THE

PIECES TOGETHER !!!

TIME

FREQUENCY

X

Y

TRANSDUCERCALIBRATION

REGRESSION ANALYSIS

HAMMER TIP CHARACTERIZATION

FOURIER SERIES & FFT

m

k c

x(t) f(t)

SDOF DYNAMIC

MODEL APPROXIMATION

SYSTEM MODEL

100

10

1

ω/ωn

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

ζ=0.1%

ζ=1%

ζ=2%

ζ=5%

ζ=10%

ζ=20%

0

-90

-180ω/ω n

)t(fxkdtdxc

dtxdm 2

2

=++

DIFFERENT PULSE SHAPES

)ps(a

)ps(a)s(h *

1

*1

1

1

−+

−=

FREE BODY DIAGRAM& EQUATION OF MOTION

LAPLACE & TRANSFER FUNCTION

tsinem

1)t(h dt

d

ωω

= ζω−

FIRST & SECOND ORDER SYSTEMS

SIGNAL CONDITIONER RISE & SETTLING TIME

ASEE Conference – June 2006 – Chicago, Illinois