IJEE1540

The Experiential Engineering Library*

JOHN E. SPEICH, JAMES T. MCLESKEY, JR., JUDY S. RICHARDSON andMOHAMED GAD-EL-HAKVirginia Commonwealth University, Richmond, VA 23284, USA. E-mail: [email protected]

Virginia Commonwealth University is developing an NSF-sponsored Experiential EngineeringLibrary that will provide an easily accessible environment for hands-on engineering learningexperiences beyond the traditional mechanical engineering curriculum. The library will fostercritical thinking by encouraging students to apply fundamental mechanical engineering principles toemerging interdisciplinary research in fields including microelectromechanical systems (MEMS),bioengineering, and nanotechnology. The present article describes the library concept, elaborateson its contents and provides some preliminary findings.

INTRODUCTION

IN PREPARATION FOR solving twenty-firstcentury problems, todays engineering studentsneed twenty-first century examples. These studentsalso express a need for hands-on activities to helpthem understand the theories they learn in class.Satisfying both these needs within the typicalmechanical engineering curriculum is becomingan increasingly greater challenge. In order tomeet this challenge, the VCU Mechanical Engin-eering Department is developing a novel Experi-ential Engineering Library with three broadobjectives. First, the library will provide an easilyaccessible and readily available environment forhands-on engineering learning experiences beyondthe traditional mechanical engineering curriculum.It will foster critical thinking by encouragingstudents to apply fundamental mechanical engin-eering principles to emerging interdisciplinaryfields including microelectro-mechanical systems(MEMS), bioengineering, and nanotechnology.Finally, it will encourage collaborative team-based learning among peers as well as mentoringby more senior undergraduates, graduate students,and faculty.

The experiential library is envisaged to be analo-gous to a traditional library. It will ultimatelycontain a large number of experiments and compu-ter simulations either on reserve or available to bechecked out by the students. At the instructorsdiscretion, hands-on problems will be assigned as acomplement to or in lieu of paper-and-pencilhomework. The equipment can also be used inde-pendently by students seeking to improve theirunderstanding through manipulation and visual-ization. Additional activities will provide enrich-ment opportunities for both undergraduate andvisiting secondary-school students. The flexibilityand integration of the experiments in the library

make it superior to laboratories used in traditionalengineering courses.

The library collections will allow students tostudy problems of interest in emerging fields thatcome from a number of sources, including: facultyresearch, senior capstone design course projects,commercially developed educational tools, anddonations from industrial partners. Our facultyincludes experts in smart materials and nanoma-terials, surgical and rehabilitation robotics, tradi-tional and alternative power generation, acousticsand vibration, flow control and MEMS. Theseexperts will provide examples from their researchthat excite the students while teaching fundamen-tal principles. For example, students can buildnanotechnology-based solar cells from simplematerials or measure their grip strength using arobotic device for hand rehabilitation therapy. Inthe past, senior design course students have builtan adaptive video game controller for childrenwith disabilities, a hang glider simulator completewith support sling, and a fully functional, continu-ously variable transmission. Teams of students willbe encouraged to develop projects for the librarythat demonstrate important engineering concepts.

Utilizing support from the U.S. NationalScience Foundation, the library is being initiatedon a small scale first. During the first year, theproject has five specific aims:

1. To develop a collection of hands-on experi-ments that demonstrate fundamental principlesto be piloted in three core mechanical engineer-ing courses (Thermodynamics; Mechanics ofDeformables; and Dynamics) and one technicalelective (Energy Conversion Systems).

2. To initiate the library by locating the experi-ments in a central setting readily accessible toall students.

3. To incorporate the experiments into fourcourses through both mandatory homeworkassignments and voluntary extracurricularlearning activities.* Accepted 30 May 2004.

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Int. J. Engng Ed. Vol. 20, No. 6, pp. 10221033, 2004 0949-149X/91 $3.00+0.00Printed in Great Britain. # 2004 TEMPUS Publications.

4. To measure the impact of the library on studentinterest, performance, and retention.

5. To hold a workshop with all mechanical engin-eering faculty to formulate a plan to fullydevelop the library and integrate other coursesin subsequent years.

The hands-on experiential learning laboratorywill enable students to reinforce their understand-ing through manipulating and simulating the theo-retical and conceptual content of their lecturecourses. Incorporating experiments from facultyresearch and student senior design projects willserve to expand and promote a more holisticcurriculum that encourages comprehension. Thisarticle presents motivation for including morehands-on learning experiences in the mechanicalengineering curriculum, it describes the libraryconcept, elaborates on its contents, and presentssome initial findings.

BACKGROUND

As part of its 20032004 evaluation criteria, theAccreditation Board for Engineering and Technol-ogy (ABET) has defined a set of 11 characteristicsthat an engineering graduate must possess [1]:

(a) An ability to apply knowledge of mathematics,science, and engineering.

(b) An ability to design and conduct experiments,as well as to analyze and interpret data.

(c) An ability to design a system, component, orprocess to meet desired needs.

(d) An ability to function on multidisciplinaryteams.

(e) An ability to identify, formulate and solveengineering problems.

(f) An understanding of professional and ethicalresponsibility.

(g) An ability to communicate effectively.(h) The broad education necessary to understand

the impact of engineering solutions in globaland societal contexts.

(i) A recognition of the need for, and ability toengage in, lifelong learning.

(j) A knowledge of contemporary issues.(k) An ability to use the techniques, skills, and

modern engineering tools necessary for engin-eering practice.

These criteria can be met in any number of ways,but laboratory and hands-on activities are a keycomponent.

Across the country, a number of programs havebeen developed with the intention of increasinghands-on learning and improving engineeringeducation, particularly at the freshman level. Forexample, Pennsylvania State University offers anIntroduction to Engineering Design course forfreshmen that involves prototype building andtesting [2]. The University of Washington offersan elective freshman-level design course as part of

the Engineering Coalition of Schools for Excel-lence in Education and Leadership (ECSEL) [3].The objectives of the course are to teach design andteamwork early in the curriculum and increaseretention by helping students envisage their rolein the engineering profession early in their collegeeducation. Projects in the course include buildingstructures using spaghetti and tape and disassem-bling and reassembling lawnmower engines.

The ECSEL coalition was formed to addresstwo primary goals: (1) transforming undergradu-ate engineering curricula, and (2) increasing thediversity of engineering graduates. It includesHoward University, City College of New York(CCNY), Massachusetts Institute of Technology(MIT), Morgan State University, Penn StateUniversity, and the University of Maryland [3].This program has led to the incorporation of morehands-on activities into a number of courses. TheUniversity of Washington also has its own Centerfor Engineering Learning and Teaching (CELT),which has evolved into the Center for theAdvancement of Engineering Education (CAEE)in partnership with the Colorado School of Mines,Howard University, Stanford University and theUniversity of Minnesota [4]. This center is trying toimprove engineering education by understandinghow engineering students think and learn. TheUniversity of Notre Dame has developed the En-gineering Learning Center with the mission offostering hands-on, multidisciplinary activities forstudents at all levels. The Learning Center isalso used as a testbed for developing innovativeteaching and learning methods [5]. The chair ofthe VCU Mechanical Engineering Program,Mohamed Gad-el-Hak, contributed to the Engin-eering Learning Center while serving on the facultyat Notre Dame.

One of the largest efforts of this type began in1991 when the College of Engineering at theUniversity of Colorado at Boulder started acollege-wide curriculum reform effort with anemphasis on active, team-based learning [6]. Thisled to the opening of a $17m, 34,000 sqare footIntegrated Teaching and Learning (ITL) labora-tory in 1997. The lab features design studios forboth freshman and senior projects, several groupstudy rooms, a gallery for interactive art/engineer-ing exhibits, two laboratory plazas, an activelearning center for course instruction, a manufac-turing center with machine tools and rapid proto-typing equipment, an electronics project center,and a computer simulation laboratory.

The ITL lab has several curriculum componentsincluding a freshmen design course, hands-onhomework components for many theory courses,and an interdisciplinary senior design course. TheFirst-Year Engineering Projects Course has beenhighly successful. Retention statistics show a 19%seventh-semester retention gain among studentswho took the Projects course as compared tothose who did not [7]. Another recent studyfound that the students believed that they had

The Experiential Engineering Library 1023

developed significant skills as a result of partici-pating in the First-Year Engineering ProjectsCourse [8].

Experimental laboratory modules are one ofthe key features of the ITL lab [6]. These modulesenhance traditional theory courses that cannotaccommodate a traditional laboratory compo-nent. The modules are designed to be stand-alone, portable, sequence-independent, suitablefor open-ended experimentation, and require mini-mal supervision. More than 85 modules are invarious stages of development, including 30 inthe area of mechanical engineering [9]. Modulesinclude electric motor comparison, static forcebalance, series and parallel pumps, viscosity offluids, modular heat exchanger, and musicalsignal analysis labs. These lab modules can beused for in-class demonstrations, scheduledlaboratories, and/or homework assignments.

ENGINEERING AT VCU

As in many of the other programs describedabove, the School of Engineering at VirginiaCommonwealth University also provides hands-on learning experiences for freshmen. The mechan-ical engineering curriculum at VCU includes anIntroduction to Engineering course that is takenby all freshmen in the School of Engineering. Thiscourse is based on the Introduction to Electricaland Computer Engineering course at CarnegieMellon University [10]. The course is centeredaround the assembly and testing of a smallprogrammable robot (Graymark 603A), whichgives the students practical experience.

While many schools recognize and fulfill theneed for hands-on activities at the freshman level,the level of hands-on activity often decreasesduring the sophomore and junior years whilestudents study core material. There is often asignificant gap between the freshman experience

and additional hands-on experience in junior andsenior level laboratory courses. For example, themechanical engineering curriculum at VCUprovides nine lab hours during the freshman yearand 15 during the senior year, while providing onlythree lab hours during each of the sophomore andjunior years, as is clearly shown in Table 1.

The mechanical engineering curriculum at VCUhas seven core courses that are taken during thesophomore and junior years. These seven coursesare required for a minor in mechanical engineer-ing. Only two of these courses have specific labora-tory components, Fluid Mechanics and HeatTransfer, and this laboratory content is minimal.The other five core courses, Engineering Statics,Dynamics and Kinematics, Mechanics of Deform-ables, Mechanical Systems Design, and Thermo-dynamics, do not have specific laboratorycomponents, although some instructors include afew hands-on activities. In the area of mechanicalsystems, students take a series of five courses(Engineering Statics, Dynamics and Kinematics,Mechanics of Deformables, Material Science forEngineers, and Mechanical Systems Design) beforethey receive significant hands-on experience in theEngineering Synthesis Laboratory course. Theexperiential engineering library will help bridgethe gap between freshman activities and juniorand senior laboratories by providing studentswith opportunities to gain hands-on experienceand provide instructors with a collection of prac-tical experiments for in-class demonstrations andhomework assignments.

While building on the accomplishments of theother universities, the VCU library will have aparticular focus on giving students knowledge ofcontemporary issues and experience with modernengineering techniques. In this way, the library willmake significant contributions in the developmentof the ABET characteristics, especially (a), (b), (e),(j) and (k). Helping students develop these char-acteristics while meeting their desire for hands-on

Table 1. Lab content in engineering courses in the VCU mechanical engineering curriculum

YearLab

Hours Engineering Courses With Labs Engineering Courses Without Labs

Freshman 9ENGR 101 Introduction to Engineering (3)ENGR 115 Computer Methods in Engineering (3)ENGR 215 Engineering Visualization (3)

Sophomore 3 EGRE 206 Electric Circuits (3)

ENGR 102 Engineering StaticsEGRM 201 Dynamics and KinematicsEGRM 202 Mechanics of DeformablesEGRM 204 Thermodynamics

Junior 3ENGR 301 Fluid Mechanics (1)ENGR 302 Heat Transfer (1)ENGR 305 Sensors/Measurements (1)

EGRM 300 Mechanical Systems DesignEGRM 309 Material Science for EngineersEGRM 303 Thermal Systems DesignEGRM 420 CAE DesignENGR 315 Process and Systems DynamicsEGRM 421 CAE Analysis

Senior 15 EGRM 410 Engineering Synthesis Laboratory (3)ENGR 402 Senior Design Studio I (6)ENGR 403 Senior Design Studio II (6)

ENGR 410 Review of Internship

J. Speich et al.1024

activities through twenty-first century exampleshas inspired the development of the ExperientialEngineering Library at VCU.

THE EXPERIENTIAL ENGINEERINGLIBRARY

Many of the examples currently used in engin-eering curricula seem better suited to the GreatestGeneration than to the students in school today.While some of these examples are still education-ally sound, twenty-first century students needtwenty-first century examples. Our experimentsare intended to promote learning through guidedinquiry. There is a constant battle in educationalcircles between traditional explicit instruction,where students are told what they need to knowand are then expected to know it, and discoverylearning, where students are given a few para-meters and then are given the chance to playand figure out the way things work. The formerseems more efficient and most engineering facultyseem more comfortable with this method. It isrelatively easy to grade objectively (right orwrong) and is well-suited for preparing studentsfor standardized tests. The latter reflects construc-tivist learning theory [11, 12], which has beenshown to engage learners more effectively thantraditional lecture instruction. Components of aconstructivist environment include: shared know-ledge; authentic, real-world tasks; scaffolding;cognitive apprenticeship; learner control; andnon-linear instruction [13]. It therefore encouragescollaborative learning and team-building. The aimof the library is for the students to perform guidedexperiments and discover the answers to theirquestions.

The library collection will be taken from facultyresearch, senior capstone design course projects,commercially developed educational tools, anddonations from industrial partners. The mechan-ical engineering faculty at VCU are conductingcutting-edge research in fields such as smart mate-rials and nanomaterials, surgical and rehabilitationrobotics, photovoltaics, acoustics and vibration,flow control and MEMS. These areas are notonly of interest to the national and internationalscientific communities, they also spark interestamong students. Examples from this research willbe incorporated into experiments that can beperformed by students in the library.

All undergraduates in mechanical engineering atVCU must complete a senior design project inteams of two to four students. These projectsprovide an excellent source of experiments forthe library. The topics covered in the core coursesand the associated areas of difficulty are fresh inthe minds of these seniors and they have uniqueinsights into ways of presenting the material toenhance understanding. This effort can lead tomentoring by upper-classmen and collaborationbetween upper- and under-classmen. It also

provides a sort of teacher training for preparingthe faculty of tomorrow.

Every engineering student at VCU is required tocomplete a summer internship before graduatingand the VCU School of Engineering has developedstrong relationships with many local businesses.These industrial partners can provide assistance tothe library in the form of both state-of-the-artequipment and mentoring by experts working inthe field. This will further strengthen the librarysrelevance to modern engineering issues.

In order for the library to be used by thestudents, it must be in a convenient location andopen for a sufficient number of hours. At thisstage, the library is being located in two labora-tories belonging to the principle investigators.These laboratories are both located in the Schoolof Engineering building at VCU where nearly all ofthe engineering classes are taught. The library willbe kept open approximately 20 hours per week byundergraduate librarians. These librarians will betrained to monitor and maintain the experimentsand assist students that visit the library. Specificinstructions will be included with each experimentand also posted on the web. These instructions willbe written in a way that will encourage self-guidedlearning.

The courses earmarked for inclusion in the firststage of the library development are Thermody-namics, Mechanics of Deformables, Dynamics,and Energy Conversion Systems. The experimentswill be incorporated into these courses in a numberof ways. While traditional in-class demonstrationscan be instructive, the intention of the library is toinvolve the students more directly. Instead ofrestricting activities to pencil-and-paper home-work, assignments will be made that require useof the library. Certainly traditional homeworkproblems will continue to be assigned, but someof these will be replaced or supplemented withexperiments in the library.

Another area where the library will be useful isin the development of reserve materials. Muchlike the reserve reading materials that are oftenincluded on a syllabus, these extracurricularassignments would give all students a way toenhance their understanding, especially thosewhose learning styles include kinesthetic andmanipulation techniques. We recognize that thetraditional reserve readings are under-utilized. It isour hope and belief that hands-on experimentsdesigned around state-of-the-art research (solarcells, robots, MEMS, smart materials, etc.) willstimulate more interaction and interest in learningamong students.

Other types of assignments may be developed aswell. Team projects can be developed for bothusers and suppliers of the library. For users,theoretical calculations done in class can bechecked in the lab. Criteria can be added tosenior design requirements that encourage thedesign teams to design projects that can be usedin the library following completion.


The experiential library will be comparable to atraditional library, in that it will contain materialseither on reserve or available to be checked outby the students. Of course, the collection will becomprised of experiments and computer simula-tions rather than books. As an initial step increating the library, a set of experiments is beingcollected.

THE LIBRARY COLLECTION

Examples of some specific experiments currentlybeing developed for the library include forcesensing in robotic surgery using smart materials,the dynamics of rehabilitation robots, and thethermodynamics of nano-crystalline solar cells.These experiments are described in detail in thissection.

Experiment # 1: Using Force-Sensing SurgicalInstruments to Illustrate Fundamental Principlesin the Mechanics of Deformables Course

BackgroundA surgeons ability to control the forces he or

she is applying to a patient during a surgicalprocedure is critical to the success of any surgery.Research is currently being conducted at VCU todevelop force sensors that will enable directmeasurement of the instrument tip forces duringminimally invasive surgery. Feedback from theseinstruments will reduce the number of errorsduring surgical procedures and allow quantitativeassessment of surgical skills during both conven-tional and robot-assisted surgery. These surgicalinstruments can also be used to demonstrateseveral basic engineering mechanics conceptstaught in Mechanics of Deformables courses.

State-of-the-art smart materials are being usedto develop the force-sensing surgical tools. Preli-minary experiments were conducted to test thefeasibility of using PZT material as a sensor on alaparoscopic surgical grasping tool. A PZT layerwas cut to the size of the gripping surface andtaped on one side of the gripper as shown in Fig. 1.In addition, a strip of PZT material embedded in astrip of stainless steel was taped onto the toolshandle as shown in Fig. 1. Both sensors were thenconnected directly to an oscilloscope that couldcapture the voltage response signal when triggeredby a change in the signal. The surgical instrument

was used to push on a piece of synthetic tissue thatwas used to simulate human tissue. The responsesfrom the PZT materials are shown in Fig. 2. Nospecial filtration circuitry is used on these measure-ments, so the signals are noisy. Nevertheless, aclear signal response was captured from bothpieces of PZT. The applied force was alsomeasured using an ATI Nano17 force sensor(ATI Industrial Automation, Inc.) placed under apiece of synthetic tissue. The force magnitude isalso shown in Fig. 2. Notice that the responses ofboth pieces of PZT clearly correlate with themagnitude of the applied force. In additionalexperiments, different levels of force were appliedto the tissue using the surgical tool and theresponses of both pieces of PZT material wererelated to the magnitude of the applied force inapproximately linear relationships. These simpleexperiments show the feasibility of using PZT as aforce sensor for surgical instruments.

Fundamental principles demonstratedSeveral fundamental concepts taught in

Mechanics of Deformables courses can be illus-trated using the feasibility experiments for theforce-sensing surgical instruments describedabove. The shaft of the laparoscopic graspinginstrument is essentially a long slender hollowcylinder, which is a geometric shape commonlyused in examples in the course. The instrument canbe used to demonstrate several different loadingconditions discussed in the course. Pushing orpulling axially on the instrument creates an axialload, twisting the instrument creates a torsionalload, and pushing laterally on the instrumentcreates a bending load. Combined loadings, suchas combined axial and torsional loading, can alsobe demonstrated. The strain in the material causedby these loading conditions varies with the type,magnitude, and point of application of the load.The strain also varies with position throughout theinstrument. The relationships between strain, loca-tion, and loading conditions can be illustrated byusing smart materials to measure the strain (orgenerate a voltage proportional to the strain) atselected locations on the instrument.

Student activities for the experiential engineeringlibrary

A Force Sensing Surgical Instrument Experi-ment is being created for the Experiential

Fig. 1. A surgical grasping instrument with PZT sensors attached to the shaft and grippers.


Engineering Library. The experiment will includeseveral surgical instruments with PZT strainsensors placed at a couple of different locationson each instrument. The data acquisition equip-ment will consist of an oscilloscope and computerfor collecting data from the smart material sensors,and an ATI multi-axis force/torque sensor formeasuring the external loading conditions.

Students will use surgical instruments to applyforces to the force/torque sensor while collectingstrain data from the smart material sensors. Theywill apply fundamental concepts being learned inthe Mechanics of Deformables course to examinethe relationships between the strain magnitude,strain location, load type, load magnitude andload location. This information will be used tocalibrate the instruments. Once calibrated, thestudents will be able to use the instruments toperform suturing tasks on samples of syntheticskin and compare measurements from the smartmaterial sensors to measurements from the force/torque sensor as they record the forces applied tothe skin.

These experiments will also be used as an in-class demonstration during the first week of theMechanics of Deformables class to emphasize theimportance and practicality of the concepts to belearned in the course. Homework assignments willbe assigned to teams of students to performspecific activities with the experiments. In addi-tion, students will have access to the experiments

throughout the semester, so they can learn throughindependent activities.

Impacts on student learningA typical demonstration in a Mechanics of

Deformables class might include the use of conven-tional strain gages to measure the strain in anobject without a specific application. In contrast,the proposed activities demonstrate fundamentalprinciples using state-of-the-art smart materials inan interesting real-world biomedical application.These activities will be especially interesting forBiomedical Engineering students that are requiredto take this Mechanical Engineering course. Theseexperiments will also encourage undergraduates toparticipate in research activities in this area.

Experiment # 2: Using a Rehabilitation Robot toIllustrate Fundamental Principles in the Dynamicsand Kinematics Course

IntroductionA robotic device for delivering rehabilitation

therapy to the hand and fingers is currentlyunder development at VCU. This device can meas-ure the position and orientation of the fingers in aplane perpendicular to the palm of the hand andcontrol the forces acting on fingertips using aplanar five-bar mechanism. The photographs inFig. 3 show side and top views of this mechanismwithout the actuators. The photographs in Fig. 4

Fig. 2. Voltage responses for PZT sensors on the handle and grippers of a surgical instrument when a force is applied to theinstrument tip.


demonstrate the range of motion of the prototype.In addition to delivering rehabilitation therapyand characterizing the function of the hand andfingers, this robotic device will serve as an excellenthands-on tool for teaching undergraduates thebasic principles of kinematics and kinetics ofmechanisms.

Fundamental principles demonstratedSeveral fundamental concepts taught in

Dynamics and Kinematics courses can be illus-trated using the robotic rehabilitation devicedescribed above. The device consists of a five-barlinkage with two rotary motors that control theposition of the fingertips in a plane perpendicularto the palm of the hand. The device is equippedwith potentiometers to measure the rotary motionof the motors and force sensors to measure theinteraction forces between the mechanism and thefingers. The forward kinematic relationships forthe five-bar linkage are used to determine theposition of the fingers when the orientations ofthe motors are known (i.e. when the motors turn,where do the fingertips move?). The inverse kine-matic equations for the device are used to deter-mine the orientation of the motors when theposition of the fingertips is known (i.e. if the goalis to move the fingertips to a specific position, howmuch do the motors need to turn?). The relation-ship between the speed of the fingers and thespeeds of the motors, as well as the dynamicrelationship between the motor torques and theforces applied to the fingers, can also be demon-strated using this device.

Student activitiesThe rehabilitation robot is a unique and expen-

sive piece of research equipment; therefore, aduplicate robot will not be fabricated for theExperiential Engineering Library. Instead, therobotic equipment located in the VCU RoboticsLaboratory will be available on reserve forstudents in the Dynamics and Kinematics courseduring the weeks when the topic of mechanismkinematics is being discussed. This will be easilycoordinated, since John Speich is both the directorof the VCU Robotics Laboratory and one of the

instructors for the Dynamics and Kinematicscourse.

The Rehabilitation Robot Dynamics and Kine-matics Experiment will include a series of inter-active activities using the robotic device. Studentswill be able use the robot to visualize the kine-matics of the mechanism by moving the end-effector of the robot and observing the motion ofthe linkage and motors, or vice versa. The compu-ter that controls the robot will be programmed todisplay both the angular positions of the motorsand the corresponding location of the fingertips.The students will develop forward and inversekinematic equations for the mechanism andcompare the results obtained from these equationswith the actual kinematics of the robot displayedby the computer. The students will also be able tostudy the relationship between the motor torquesand the forces applied by the robot to the fingers.This will be achieved by programming the robot tosimulate a virtual spring with which the studentsfingers can interact. As students push on thevirtual spring, they will be able to see the magni-tude of the force they are applying and corres-ponding motor torques displayed by the computer.These values can be recorded for comparison withvalues calculated by the student.

The rehabilitation robot will also be used for anin-class demonstration during the first week of theDynamics and Kinematics class to emphasize theimportance and practicality of the concepts to belearned in the course. Homework will be assignedto teams of students to perform specific activitieswith the experiments.

Impacts on student learningA typical demonstration in a Dynamics and

Kinematics class might include a simple mechan-ism similar to the prototype of the rehabilitationdevice shown in Fig. 4. This mechanism was madefrom a toy modeling kit and is not equipped withsensors or actuators. In contrast, the proposedactivities demonstrate fundamental principlesusing an interesting, state-of-the-art rehabilitationrobot equipped with actuators and both motionand force sensors. These activities will be especiallyinteresting for Biomedical Engineering students

Fig. 3. A robotic device for delivering hand and finger rehabilitation therapy shown without the actuators.


that choose to enroll in this Mechanical Engineer-ing course. These experiments will also encourageundergraduates to participate in research activitiesin this area.

Experiment # 3: Thermodynamics of Nano-crys-talline Solar Cells

BackgroundThe first and second laws of thermodynamics

learned in an introductory course are often taughtusing examples first developed in the nineteenthcentury to help engineers design steam engines forlocomotives. While these examples still bear rele-vance to the design of steam turbines and internalcombustion engines, the engineers of the twenty-first century need experience in applying the lawsof thermodynamics to twenty-first century tech-nology. Photovoltaic cells are such a technology.

In recent years, numerous authors have appliedthe principles of thermodynamics to solar cells[1419]. In general, the principles can be applied tosolar cells made from any material (crystalline sili-con, amorphous silicon, cadmium telluride, etc.).The nano-crystalline dye-sensitized titanium diox-ide solar cell (or Graetzel cell) has the advantagethat the student can construct the cell from commonmaterials prior to performing the experiments.

Student activities and fundamental principlesdemonstrated

Using the Nano-crystalline Solar Cell Kit fromthe Institute for Chemical Education [20], studentscan build their own solar cells in a lab using simplematerials, including titanium dioxide and black-berry juice. The resulting solar cells can then betested for important values, including voltage andcurrent (and thus power). For a known solar flux,the energy conversion efficiency of the solar cellcan be calculated.

The nano-crystalline solar cell shown in Fig. 5can be used to help teach the concepts covered inany number of mechanical engineering courses.The first and second laws of thermodynamicsand energy conversion efficiency [1418] can allbe demonstrated for a course in Thermody-namics. Unique calorimetry measurements canbe made to identify loss mechanisms in thesolar cell [19] and thus teach the concepts ofconductive and radiative Heat Transfer. For acourse in Energy Conversion Systems, the rela-tionship between different forms of energy can bedemonstrated by storing the output from the cellin a capacitor and later using that energy topower a motor or an LED. The challenge ofproducing large quantities of energy at low costcan also be presented.

Fig. 4. Prototype of the hand rehabilitation robot demonstrating the range of motion of the five-bar mechanism.

Fig. 5. Dye-sensitized nano-crystalline solar cell.


Impacts on student learningThe promise of free energy offered by photo-

voltaic solar energy conversion is very enticing tostudents. This experiment offers them the oppor-tunity to build a nano-crystalline solar cell whilelearning about the limits imposed by the first andsecond laws of thermodynamics. It also illustratesthe interrelationships between the various disci-plines of science and engineering and could beused in teaching Thermodynamics, Heat Transfer,and Energy Conversion Systems. This gives thestudents the opportunity to revisit the same experi-ment as they learn new concepts, thus helping tobuild continuity.

These three experiments will form the foundationfor the library collection. Students will utilize theexperiments in four separate courses and the impactof the library on student learning will be evaluated.

ASSESSMENT OF THE LIBRARY

Measuring the effectiveness of the library will bea challenge [21]. One important task during theinitial development of the library will be identify-ing the best methods for assessing the impact of thelibrary on student learning. Ways of measuring theinfluence of the library on student knowledge(cognitive thinking), thought processes (attitudinalthinking) and skills (behavioral thinking) will beexplored during the full implementation phase. Asa best first effort at evaluating the concept duringthe first year, a number of assessment techniques,both qualitative and quantitative, will be employedto measure success.

One critical qualitative measuring stick isstudent perceptions [21]. These perceptions canaffect both subsequent learning as well as retentionrates and will be measured using student self-assessments. Students will demonstrate theirperceptions of learning by completing a pre andpost self-assessment of important terms encoun-tered during the module study. Students will alsorate, before and after completion, their learning viamodules according to objectives for learning to begained from the module. Focus group interviewswith students who experienced only the traditionallecture method and those who experienced thelibrary will be conducted to gather qualitativeexpressions of satisfaction and perception of learn-ing. A more quantitative measure of student inter-est in the hands-on activities will be measured bycomparing the number of completed traditionalhomework assignments vs. the number ofcompleted hands-on assignments to see if studentsare more or less likely to do the hands-on assign-ments.

The preliminary stage covers only four coursestaught during consecutive semesters. This makesobtaining reliable statistics on the impact of thelibrary on grades, standardized test scores andretention rates during one semester challenging.Some comparisons, however, can be made with

students who have taken the class during aprevious semester. An assignment will be identifiedthat can be given in both the traditional classroomand with those who use the library; the assign-ments will be compared for difference in cognitivethinking, behavioral thinking, and attitudinalthinking. Students will create concept maps todemonstrate their learning; these maps will becompared. Grades on projects between the twogroups of students will be compared. In addition,by monitoring library usage, it will be possible tocompare the number of hours spent in the libraryagainst the semester grade and determine anycorrelation.

In the first year, monitoring long-term studentretention rates is not possible. As the projectmoves into a full implementation stage, the reten-tion rate of students in the mechanical engineeringprogram can be analyzed to determine if studentinterest and persistence have been altered throughimplementation of the library.

The School of Engineering has teamed with theVCU School of Education for this program. JudyRichardson, a professor from the School of Educa-tion, is responsible for advising the MechanicalEngineering Program on methods of assessmentand evaluation and assisting with the interpreta-tion of results. She will also provide insight andhistorical perspective on the effectiveness of vari-ous teaching models.

PRELIMINARY RESULTS

The Experiential Engineering Library was firstpiloted in the curriculum during the fall 2003semester in a senior technical elective course:Energy Conversion Systems. The results of thefirst module, in which the students built a simpleStirling engine, are presented below. This modulewas a homework assignment with no prior intro-duction in class. Although the experiment is avail-able commercially in kit form, it nonethelessrepresents the state-of-the-art in Energy Conver-sion Systems and is the subject of ongoing research[22]. An evaluation of the impact of the module onstudent learning was conducted using pre and postself-assessments and the results of these self-testsare presented.

The Stirling engine module (see Fig. 6) wasbased on a model available in kit form fromFisher Scientific [23]. The model uses a test tubeand marbles as the transfer cylinder and piston anda rubber stopper and balloon as the power cylinderand piston. All 19 students in the Energy Conver-sion Systems course completed the Stirling enginelibrary module over the course of one week. Eachstudent worked independently. The students weregiven a nine-question pre-test to assess their know-ledge of Stirling engines. They were also asked torate their existing knowledge of Stirling engines ona scale from one (no knowledge) to ten (expert).After completing the experiment, they were given a


post-test. The post-test included the same ninequestions and self-rating. In addition, the studentswere asked whether the lab was helpful in increas-ing their knowledge of Stirling engines andwhether or not the lab peaked their interest inStirling engines. Finally, the students were giventhe opportunity to make written comments. Theaverage percentage of correct responses was 69.6%on the pre-test and 94.1% on the post-test, withstandard deviations of 13.3% and 9.3% respec-tively. The averages are presented graphically inFig. 7 with error bars that show 1 standard

Fig. 6. Stirling engine model [23] used in the Experiential Engineering Library.

Fig. 7. Average percentage of correct responses for the Stirling engine pre-test and post-test. The error bars show 1 standarddeviation.

Table 2. Students written comments about the Stirling enginemodule

Great interactive learning experience.Lab helped me understand how the Stirling engine worked.I am going to build one at home.Cool lab. Stirling engs are very interesting.More detailed diagrams w/ instructions would help.Fine-tuning the engine to work properly is difficult.I kinda got it to work.I have never seen a Stirling engine before and never thought

that it was so simple.Fun lab. Finiky engine.


deviation. Clearly, reading the instructions andcompleting the module improved the studentsabilities to answer the questions correctly.

As stated above, each student rated his/herexisting knowledge of Stirling engines on a scalefrom one (no knowledge) to ten (expert) beforeand after completing the library module. Theaverage rating was 2.8 on the pre-test and 7.1 onthe post-test, with standard deviations of 1.6and 1.8 respectively. The averages are presentedgraphically in Fig. 8 with error bars that show 1standard deviation. When asked whether or notthe lab was helpful in increasing their understand-ing of Stirling engines, seventeen out of nineteen(89%) answered affirmatively. The students clearlybelieved that they had increased their expertise. Itshould be noted, however, that one of the twostudents who rated their knowledge as 10 on theself-evaluation did not answer 100% of the post-test questions correctly, but a student who ratedhis/her post-lab knowledge as two did answer100% of the questions correctly. Students alsofound the lab enjoyable and intriguing. Fifteenout of nineteen (79%) said the lab peaked theirinterest in Stirling engines. This is also supportedby the student comments listed in Table 2.

CONCLUSIONS

Virginia Commonwealth University is develop-ing the Experiential Engineering Library toprovide an easily accessible environment forhands-on engineering learning experiencesbeyond the traditional mechanical engineeringcurriculum. The library will foster critical thinkingby encouraging students to apply fundamentalmechanical engineering principles to emerginginterdisciplinary research in fields including micro-electromechanical systems (MEMS), bioengineer-ing, and nanotechnology. Experiments will comefrom state-of-the-art faculty research as well asother sources and can be assigned as a comple-ment to or in lieu of paper-and-pencil home-work or utilized independently by studentsseeking to improve their understanding of parti-cular concepts. Used initially in four courses,the library will be evaluated for effectivenessand then implemented across the curriculum.

AcknowledgementsThe authors would like to acknowledge theNational Science Foundation for its support of this projectunder the Grants for the Department-Level Reform of Under-graduate Engineering Education Program, NSF Grant number0342865.

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Fig. 8. Average self-evaluation scores in which students rated their knowledge of Stirling engines on a scale from one (no knowledge) toten (expert) before and after completion of the Stirling engine library module. The error bars show 1 standard deviation.


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John Speich is an Assistant Professor of Mechanical Engineering at Virginia Common-wealth University. He received his B.S. in Mechanical Engineering from the TennesseeTechnological University and his M.Sc. and Ph.D. in Mechanical Engineering fromVanderbilt University.

James McLeskey is an Assistant Professor of Mechanical Engineering at VirginiaCommonwealth University. He received his B.Sc. in Physics from The College of Williamand Mary, his M.Sc. in Mechanical Engineering from the University of Illinois at Urbana-Champaign, and his Ph.D. in Mechanical Engineering from the University of Virginia. Dr.McLeskey is certified by the State of Virginia to teach high-school Physics and Chemistry.

Judy Richardson is a Professor in the School of Education at Virginia CommonwealthUniversity. She received her B.A. in English from the University of North Carolina,Greensboro, and her M.Ed. and Ph.D. in Education from the University of NorthCarolina, Chapel Hill.

Mohamed Gad-el-Hak is the Caudill Eminent Professor and Chair of Mechanical Engin-eering at Virginia Commonwealth University. He received his B.Sc. in MechanicalEngineering from Ain Shams University and his Ph.D. in Fluid Mechanics from JohnsHopkins University. Dr. Gad-el-Hak is a fellow of the American Academy of Mechanics,the American Physical Society, and the American Society of Mechanical Engineers.


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