Introducing Data Acquisition And Experimental Techniques ...

Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright ã 2002, American Society for Engineering Education

Session____

Introducing Data Acquisition and Experimental Techniques to Mechanical Engineering Students in the Freshmen Year

Risa J. Robinson, John Wellin

Rochester Institute of Technology, Mechanical Engineering Department

1 Introduction In a recent survey of 420 engineers and engineering managers from 24 companies, the ability to design and conduct experiments was rated as one of the highest desirable technical skills they look for in engineering graduates.1 Specifically, the survey stated that employers want engineering graduates with a working knowledge of data acquisition, analysis and interpretation, a demonstrated ability to formulate a range of alternative problem solutions and computer literacy in simulation, modeling and other tools specific to their profession. The educational community recognizes that the typical engineering curriculum has steadily decreased the emphasis on the study of experimental techniques for problem solving, and as a result, has become a detriment to the profession2. These recent trends are confirmed by results from exit interviews of Mechanical Engineering (ME) seniors at Rochester Institute of Technology (RIT). Apparently, our students at RIT are confident in their analytical and design abilities, but lack the skills and confidence necessary to build and test their designs. They expressed the concern that the current electronics course was not significant nor applied enough to enable them to participate in multidisciplinary projects and co-op opportunities involving electrical and computer components, sensors, data acquisition software or controls. Students suggested that more hands on data acquisition and analyses projects throughout the curriculum, would be extremely valuable in preparation for the workplace. RIT is addressing these needs by developing a new curriculum based on the Enhanced Educational Experience for Engineers Program (E4) which was pioneered by Drexel in 19883. A critical component of E4 is the Engineering Test, Simulation and Design Laboratory (ETSDL)4, the adaptation of which defines the scope of this paper. The ETSDL is based on the belief that experimentation is a critical element of the engineering profession, continuous experiences in experimentation are desirable from a pedagogical point of view, and early hands on experiences enhance student interest and motivation toward engineering at a time when career decisions are being made. These principles are supported by recent data from the educational literature.5,6,7,8,9 Since its inception in 1988, several colleges have adapted versions of the E4 program to their curriculum. One study conducted in 1999 indicates that the retention rate of E4 schools compared

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to traditional schools had increased by as much as 40%.5 Another study found that simply converting an Introduction to Engineering course from lecture based to a laboratory format increased retention by 17% for the general population, 45% for women and minorities6. These reports are supported by studies that suggest high attrition rates are due to the lack of hands on experience to support and clarify abstract theoretical material.7 This is particularly troublesome for the non traditional student who may lack the pre-college experience of tinkering with mechanical objects.8 Other studies point out that laboratory courses provide continuous motivation throughout the demanding curriculum of the first two years. 9 Freshmen at RIT tell us that they were attracted to mechanical engineering by the desire to know how things work, but quickly loose interest as they are overloaded with basic math and science courses. Essential as these preparatory courses are, they seldom convey the flavor of real world engineering and do little to sustain student interest. Attempts to give freshmen a glimpse of the future by bringing in upper classmen and practicing engineers have had little effect. Students want and need to experience real world engineering in the first quarter of the first year. Clearly, incorporating a laboratory based course in the freshmen year will have a positive effect on retention rates by enhancing the reception of theoretical material and sustaining student interest in engineering. Pedagogically it is beneficial to introduce experimental techniques and tools early and reinforce them continuously throughout the curriculum. This method takes students through all the levels of learning on the Perry scale (Dualism, Multiplicity, Contextual Relativism, and Commitment within Relativism).11 The Perry model suggests that students come to college with the idea that teachers are the absolute authorities, and that solutions are either right or wrong. As Professors our goal is to facilitate student progression from this level of thinking to the highest level where students believe that they are legitimate sources of knowledge, that problems have many possible solutions, and that the perfect problem solution does not exist. Students are encouraged to move up the Perry levels as they are presented with progressively more challenging problems as they progress through the engineering curriculum. This knowledge base defines a unique perspective on the current status and recent trends in engineering education. It is from this base that we define our program objectives, shape the facilities, and derive the subject matter for the new curriculum. 2 Goals and Objectives Recent trends in industry and education indicate the need to place more emphasis on the study and practice of experimentation in the engineering curriculum. The Mechanical Engineering Department at RIT will address this need by integrating hands-on laboratory experience throughout its curriculum starting with the first quarter of the freshmen year. This effort will be modeled after the Enhanced Educational Experience for Engineers, Drexel’s E4 program. A critical component of E4 is the Introductory Engineering Test, Design and Simulation Laboratory.

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This laboratory will be integrated into several courses for the purpose of achieving the following educational objectives: 1. Produce competent, experienced students proficient in the art of experimentation who can

participate in and benefit from much more sophisticated upper level laboratory and design experiences than is currently possible.

2. Increase retention, especially for minorities and women by stimulating freshmen learning and motivation toward engineering through hands-on laboratory experiences in the first year.

3. Provide students with access to the necessary industry standard hardware and software required for data acquisition, instrumentation and controls for use in required courses, open-ended course projects, senior design projects and undergraduate research.

4. Develop a curriculum that fosters discovery, promotes self-teaching and encourages the desire and ability for life long learning.

5. Broaden the faculty expertise in state of the art experimental techniques in preparation for future course development in multidisciplinary topics such as MEMS actuators and sensors.

3 Methodology This program proposes to create a comprehensive laboratory experience for undergraduate students, illustrated in Figure 1, by integrating laboratory experiences into several courses and minority outreach programs. Specifically, we plan to develop 1. a Data Acquisition (DAQ) Laboratory equipped with industry standard equipment, 2. a two sequence Freshmen Laboratory course in Measurements, Instrumentation and Controls.

(MIC I and MIC II), 3. a two sequence third year Experimental Projects Laboratory course in Fluid Mechanics and

Heat Transfer (FHL I and FHL II), 4. open ended experimental projects and classroom demonstrations utilizing the DAQ

Laboratory for a variety for undergraduate courses, and 5. innovative and advanced laboratory experiences for existing RIT minority outreach programs.

Figure 1. Schematic of integration of DAQ laboratory into the curriculum.

CCLI Proposed DAQ Laboratory

Freshmen Laboratory

Courses MIC I and II

Experimental Projects Courses

FHL I and II

Sophisticated Classroom

Demonstration Experiments

Open ended Projects in

Undergraduate Curriculum

Incorporation into Outreach Programs for Minority and Women

High school Students and Teachers

OUTCOME: Integrated Lab Experience for Undergraduate Students from Freshman to Senior Year, and providing services for minority and women pre-college students teachers.

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4 Time Line The project is divided into the following tasks: DAQ Lab development, incorporation of MIC I and II into the freshmen year and incorporation of FHLI and II into the third year. Figure 2 shows a time line for completion of this project. The development of the DAQ Lab will be completed by the end of Summer 2001. Courses MIC I and II will be offered to a pilot group in the academic year 2001-02 and 2002-03. This pilot group of students will then take a pilot project based Thermo/fluids lab in place of the traditional format11 in their 3rd year. The outreach programs are ongoing and will be discussed in other papers.12 In the following sections, we describe the development of the DAQ Lab and the first course in Measurements, Instrumentation and Controls. Subsequent articles will present the work as it is completed according to the timeline. 5 Data Acquisition Laboratory Test and measurement facilities in the Measurements, Instrumentation & Controls Lab (MICL) have been chosen with two goals in mind: the immediate support of the freshman instructional courses, and future integration and expansion throughout the Mechanical Engineering curriculum. National Instruments (www.ni.com) has been chosen as the primary vendor for data acquisition hardware and software. National Instruments (NI) is a recognized leader in test and measurement development, with a predominant market share of all such facilities sold in the US and throughout the world. In fact, many original equipment manufacturers supply drivers to allow integration of their hardware with LabVIEW, NI’s flagship graphical programming application. LabVIEW greatly simplifies data acquisition and analysis, especially for the novice user, without sacrificing higher-level capabilities. In addition, NI supplies its basic hardware configuration utilities free of charge. The latest version of these utilities is its Measurement & Automation Explorer (MAX), which allows windows-based testing and control of all NI hardware. MAX can be tightly integrated with LabVIEW for its fullest potential, but can also be used in conjunction with virtually any second-party application. In short, the expansive capabilities and industry presence of National Instruments products make them the ideal choice for the MICL and associated curricular uses. Eight identical workstations have been constructed in the MICL for instructional and distributed data acquisition purposes, each designed to accommodate at least two students at a time (Figure 2). Each station is mobile courtesy of an Anthrobench heavy-duty table with castors and various inboard and outboard shelves (Anthro Corporation, www.anthro.com). At the heart of each station is a PCI-6052E Multifunction I/O DAQ Board, with 16 single-ended (8 differential)

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analog input channels, 333 kS/s sampling rate, and 16-bit resolution; 2 analog output channels with 16-bit resolution; one digital input/output port (eight 5V/TTL lines); 2 up/down 24-bit counter/timers; and analog or digital triggering. The DAQ board is installed in one PCI slot of a Dell Precision 330 Workstation running Microsoft Windows 2000 on an Intel 1.4 GHz Pentium 4 Processor with 394 MB RAM and a total of 60 GB hard disk space. Each workstation uses a dual 19” monitor setup powered by a Matrox Millennium G450 Dual Head graphics adapter, which has proven ideal for programming in LabVIEW with its otherwise dichotomous “front” user interface pane and “rear” block diagram. The latest version LabVIEW 6i is independently installed on each machine, as well as Microsoft Office 2000. Very few other applications or utilities have been installed, since the stations are dedicated to the MICL mission. The DAQ board is not a stand-alone appliance, in that it must somehow be physically interfaced to external measurement devices. Three separate hardware schemes have been installed for such purposes. The first is a relatively simple DAQ Signal Accessory from NI that allows introductory use of a subset of the analog, digital, and counter facilities of the DAQ board, as well as some introduction to measurement devices (such as a built-in quadrature encoder). Although a limited number of generic inputs and outputs can be directed through the signal accessory, its fundamental purpose is basic instruction and hardware illustration. The next level of sophistication is the BNC-2090 Shielded BNC Adapter Chassis, which allows direct, simple connectivity to all analog channels via BNC connectors, as well as spring-terminal connections for all remaining channels. The primary use of the BNC-2090 thus far has been for accessing unconditioned input signals, and simple interfacing to external devices for control purposes. The third, most sophisticated scheme is a 12-slot SCXI-1001 chassis for Signal Conditioning for External Instrumentation. The SCXI chassis is an expandable and customizable backplane with independent power supply that supports plug-in “modules” designed for specific measurement and/or control applications. A total of 6 modules have been installed in each chassis, leaving 6 slots free for future expansion. These modules allow for a wide range of measurement applications, including but not limited to temperature, strain, force, position, pressure, acceleration, and the like. The specific modules include a 32-Channel Thermocouple Input Module (SCXI-1102); a 32-Channel Analog Input Module (SCXI-1104); an 8-Channel Isolation Amplifier Module (SCXI-1125); an 8-Channel Universal Strain Gauge Input Module (SCXI-1520); an 8-Channel Accelerometer Input Module (SCXI-1531); and a Feedthrough Panel (SCXI-1180). Default operation multiplexes all signals from all modules to the first two input channels of the DAQ board. The lattermost feedthrough module allows access to all other channels of the board when connected to the SCXI chassis. Each module additionally requires a “terminal block” for making actual field wiring connections. A variety of terminal blocks have been obtained, some of which are specialized for the corresponding module (such as that for the strain gauge module). The SCXI-1102 and SCXI-1104 are outfitted with the TC-2095 and BNC-2095 terminal blocks, respectively, which are rack-mountable for further ease of connection. The TC-2095 allows standard “mini-plug” connections for thermocouples.

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Together the BNC-2090, the SCXI chassis with modules, and the two 2095-series terminal blocks are mounted in a custom-made rack assembly for ready access at each station (Figure 3). Finally, each station is also outfitted with a Shenzhen-Mastech triple-output DC power supply from RSR Electronics, Inc. (www.elexp.com); a model #HHM290 Supermeter digital multimeter/thermometer from Omega Engineering, Inc. (www.omega.com) capable of measuring voltage, current, resistance, frequency, capacitance, and temperature; basic hand tools including a wire stripper and screwdrivers; a full complement of equipment manuals; and an assortment of test leads, coaxial cables, and BNC connectors. Each station is thus designed to be a fully self-sufficient data acquisition facility.

Figure 2. Data Acquisition Laboratory Workstation.

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Figure 3. Mounted rack assembly including BNC–2090, SCXI chassis with modules and 2095-series terminal blocks.

6 Measurements, Instrumentation and Controls I The freshmen laboratory courses, MIC I and II, are adapted from work completed by Colorado School of Mines,13 Drexel3, and the Community College of Philadelphia. Changes were made in experimental topics to better suit the background and interests of mechanical engineers. The course sequence objective were to equip students with the fundamental laboratory techniques and to familiarize them with hardware and software tools that will enable them to participate in upper level course projects. The first course in the sequence was designed to give the students

i. actual hands on engineering experience in the first quarter of the freshmen year ii. a working knowledge of state of the art software and hardware that is used by industry

for data acquisition and instrumentation control

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iii. the opportunity to develop skills in areas that are critical to an engineer’s success, including teamwork, open ended problem solving and formal presentations

The following are the specific learning objective for the students, for the 2 course sequence.

i. Understand fundamental programming logic and be able to write simple programs using a graphical programming language.

ii. Become familiar with the basic computer tools that are used for data analysis and presentation including word processing, presentation and spreadsheet software.

iii. Gain experience interpreting technical literature for various sensors and actuators, and be able to determine the appropriate device for a particular application.

iv. Gain experience in developing experimental procedures to solve a given problem, to conceive, design and build the experimental apparatus, mount and calibrate transducers, install motors and pumps, wire simple circuits necessary for signal processing, feed back and controls.

v. Understand how to obtain measurements of physical parameters including pressure, temperature, strain, force, flow rate, acceleration, and how to determine material properties such as coefficient of thermal expansion, thermal conductivity, viscosity, modulus of elasticity, heat capacity, heat of vaporization and fusion.

vi. Understand important terms associated with experimentation including range, sensitivity, dynamic response, hysteresis and calibration and be able to identify systematic vs. random errors, and quantify accuracy and precision of an instrument and calculate data uncertainty, mean and standard deviation.

Figure 4 shows the syllabus for the 2 courses. During the fall quarter, we were able to complete all LabVIEW exercises and began the pump control modules. The LabVIEW exercises were extensive, taking 7 weeks and included students writing their own code to read temperature from a data acquisition accessory box, file input/output and graphing. The purpose behind spending this amount of time on programming, was to give the students the tools necessary to solve the pump problem on their own, with out step-by-step instructions. In the assessment section, we will review the students reaction to this type of teaching style. The class format was typically 10-20 minute lecture followed by 30 minutes hands on programming, with an additional 1 hour hand on time once per week. Other course activities included a guest speaker from National Instruments and a field trip to a National Instruments Conference.

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Figure 4. Syllabus for the Measurements, Instrumentation and Controls I and II pilot courses.

I. Introduction to basic programming logic and hardware necessary for computer based data acquisition and controls. (National Instrument’s LabVIEW Graphical Programming Language). Indicators and Controls; Numeric, Boolean and String data types; For, While and Case structures; File I/O; Graphs and Charts; Arrays and Clusters

II. Basic Electronic Circuits

Resistors, capacitors, parallel and series circuits, Kirkoff current law

III. Tank Level Control Modules 1. Pump 2. Flow Rate Sensor 3. Pressure Transducers 4. Solenoid Valve

III. Temperature Transducer Modules: Thermocouple, Thermistor, RTD, Thermometer

1. Range, Sensitivity, Dynamic Response and Calibration 2. Calorimetry – Heat Capacity, Heat of Vaporization and Fusion 3. Heat Transfer Coefficient 4. Thermal Conductivity

IV. Force Transducers Modules

1. Experimental Error - Systematic Vs. Random Errors, Hysteresis, Uncertainty, Accuracy, Precision, Mean and Standard Deviation.

2. Modulus of Elasticity 3. Rocket Engine Load Cell

V. Acceleration Modules VI. Experimental Team Project

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6 MIC I Course Assessment The primary purpose of the assessment was to determine how well the students were able to learn the basic programming logic and LabVIEW syntax in the time allowed. In addition, we were interested in evaluating how well the LabVIEW portion of the course prepared students to set up an experiment on their own. The goal was to give students the tools necessary to solve the problem without step-by-step instructions. In this way, students would have more fun and get a greater sense of what being an engineer is all about. This assessment involved examination of student performance on exams and student surveys. Students took a final comprehensive exam on LabVIEW, which included a 1 hour written portion and a 2 hour programming portion. Students did very well on the written exam. They were able to quickly learn the basics of using LabVIEW, including icons, mouse clicks, pull down menus, terminology. Figure 5 shows the average scores for selected topics which are typically covered in an introductory programming course. The high scores are attributed to the graphical programming environment and the ease with which students are able to visualize the flow of data. Unlike text based languages which require first the creation of a logical flow chart, graphical programming is written and debugged in a flow chart form. This makes it easier to focus on programming logic. In the second portion of the exam, students were asked to write 4 programs. The results, shown in Figure 6, are again very good for basic logic. Students had some problems with the third problem which involved graphs and arrays. This was mostly due to the confusion in the LabVIEW program between plots and graphs, and the waveform data type. Polymorphism was difficult to convey to the students, and in the future for freshmen, we would most likely try to work with only one data type. The last problem, file input/output also scored low. This was probably due to inadequate preparation before the test. Indeed, many students did not complete the last assignment on file I/O until after the exam. A survey, shown in Figure 7, was used to evaluate the students perception of their readiness to design and set up the experiment after completing 7 weeks of LabVIEW programming modules. All students considered the pace of the LabVIEW portion appropriate and most felt well prepared to construct the pump experiment. We did find however, that more time must be spent on basic circuit set up (power supply, Ohm’s Law, resistors) before beginning the experiment. This pilot course includes a higher level of technical content than previously offered in the ME department. Not only were students learning difficult data acquisition and programming concepts, but they were required to solve problems with very little direction from the instructor. Instructor observations indicate that students were able to handle the workload and most were able to meet the challenge of self learning. The results of the student survey, shown in Figure 8, indicate that students did experience learning on their own and perceived this as challenging but not too difficult. Because the work, although self directed, was done in class, the level of frustration was not unnecessarily high because the instructor was available to provide direction

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immediately when needed. In other words, for freshmen, self learning inside the classroom is not perceived as being abandoned by the instructor, as is often the case in self learning activities. The secondary purpose of the assessment was to evaluate the potential of this course to have a positive impact on retention. It was not the intent of this project to study retention and speculate on the reasons why students leave college or change majors. Instead, our goal was to provide freshmen with the activities that have been shown in other studies to have a positive impact on retention and the general well being of the students. These include experiences that are challenging, stimulating, fun and hands-on. The effects are measured in their motivation towards engineering, as shown in Figure 9. It is understood that the student response to some of these questions could be the result of many other aspects, in addition to our course. For example time and stress management, family issues, residence hall experiences, financial aid and performance in other courses all effect students attitude and perception of well being. No attempt was made to distinguish the effect of this course relative to these other factors. In general, the results indicate that students enjoyed the course, had a good idea of what engineering is all about and were happy with their choice to become a mechanical engineer and pursue this degree at RIT.

Figure 5. Assessment Results for the MIC I course. Average scores on written exam by selected topic.

Topic Average Score

if then else statement – logic and syntax 48% for loop and arrays 81% logical gates (and, or, not and, not or..) 90% for loop and tunnels 75%

Figure 6. Assessment Results for the MIC I course. Average scores on programming exam by topic.

Topic Average Score

Build a calculator – case structures, logic gates 89% Average Temperature – signal input/output, iteration loops, loop counting

82%

Graphs, arrays, LabVIEW syntax 72% Write/read file, arrays, LabVIEW syntax 70%

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Figure 7. Assessment Results for the MIC I course. Adequate preparation for design of experiments.

Number of Students

Agree Neutral Disagree I think the LabVIEW exercises adequately prepared me for the programming portion of the pump control module

8 1 3

I think more electronics background would be helpful before completing the pump control module

7 4 1

The pace of the LabVIEW section of the course was just right. 12 0 0

Figure 8. Assessment Results for the MIC I course. Self learning an difficulty level.

Number of Students

Agree Neutral Disagree The lab required me to learn of my own. 11 0 1 The lab required too much work outside of class. 0 3 9 The lab was NOT challenging enough. 0 4 8 The pilot course is TOO difficult for a freshmen level course. 0 2 10

Figure 9. Assessment Results for the MIC I course. Motivation toward Engineering

Number of Students

Agree Neutral Disagree The lab was fun. 7 4 1 The lab stimulated my curiosity about engineering. 8 4 0 The lab made me excited about being an engineer. 6 5 1 I have a good idea of what mechanical engineering is all about. 10 1 1 I still want to be a mechanical engineer. 10 1 1 I am happy about my choice to come to RIT. 9 2 1

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7 Conclusions The first phase of a project to introduce experimental design into the mechanical engineering curriculum at RIT has been completed. This phase includes the development of a new data acquisition laboratory with industry standard hardware and software and a first course in Measurements, Instrumentation and Controls. Assessment results indicate that students were receptive to the course content and methodology. Student survey results show that the course could potentially have a positive impact on retention. Completion of the remaining phases of the project will be described in future papers. References 1. Lang, J. D. et.al., “Industry Expectations of New Engineers: A Survey to Assist

Curriculum Designers”, Journal of Engineering Education, Jan 1999, pp. 43-51. 2. Quality in Engineering Education”, Executive summary of the Final Report of the ASEE Quality of

Engineering Education Project, in Engineering Education, vol. 77, No. 1, Oct. 1986, pp. 16-24, 49-50. 3. Quinn, R. G., “E4 – Genesis of a New Curriculum”, 1999 Frontiers in Education Conference, pp. 651-652. 4. Quinn, R. G., “The E4 Introductory Engineering Test, Design and Simulation Laboratory”, Journal of

Engineering Education, Vol. 82. No. 4, Oct. 1993, pp. 223-226. 5. Al-Holou, N. et. al., “First-Year Integrated Curricula: Design Alternatives and examples”, Journal of

Engineering Education, Oct. 1999, pp. 435-448. 6. Hoit, M. and Ohland, M., “The Impact of a Discipline-Based Introduction to Engineering Course on Improving

Retention”, Journal of Engineering Education, January 1998, pp. 79-85. 7. Henderson, J. M. et.al, “Building the Confidence of Women Engineering Students With a New Course to

Increase Understanding of Physical Devices”, Journal of Engineering Education, Oct. 1994, pp. 1-6. 8. Felder, R. M. et.al, “A Longitudinal Study of Engineering Student Performance and Retention. III. Gender

Differences in Student Performance and Attitudes”, Journal of Engineering Education, April 1995, pp. 151-163.

9. Hewitt, N. M. and Seymour, E., “A Long, Discouraging Climb”, ASEE Prism, Feb. 1992, pp. 24-28. 10. Pavelich, M.J., and W. S. More, “Measuring the Effect of Experiential Education Using the Perry Model,

“Journal of Engineering Education”, Vol. 85, No. 4, 1996, pp.287-292. 11. Robinson, R. J., “Improving Design of Experiment Skills through a Project Based Fluids Laboratory”,

Proceedings of the 2002 American Society for Engineering Education Annual Conference, Montreal Canada, June 2002.

12. Mozrall, J, Anderson, M., Robinson, R. J., Venkataraman, J.,“I Build my Computer @ RIT”, Proceedings of the 2002 American Society for Engineering Education Annual Conference, Montreal Canada, June 2002.

13. King, R., Parker, T., Grover, T., Gosink, Middleton, N. “A Multidisiplinary Engineering Laboratory Course”, Journal Engineering Education, July 1999, p. 311-315.

RISA ROBINSON Risa Robinson, Ph.D., is an Assistant Professor in Mechanical Engineering at the RIT. She has a B.S. in Mechanical Engineering, an M.S. in Imaging Science both from RIT and a Ph. D. in Mechanical and Aerospace Engineering from University at Buffalo. Recent research includes modeling the dynamics of particles in biological systems.

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JOHN WELLIN John D. Wellin is a Visiting Assistant Professor of Mechanical Engineering at RIT, with expertise in the areas of continuum mechanics, applied mathematics, biomechanics, experimental techniques, and data acquisition. He holds an M.S. in Mechanical Engineering from the University of Rochester, and a B.S. with highest honors from RIT. Acknowledgements This work was supported by a National Science Foundation, Course, Curriculum and Laboratory Improvement -Adaption and Implementation Grant, # 0088779.

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