EngineeringQuarterly
leadingaprojectthatwasapprovedbythe governorfor$50,000inmonumentrestoration.”
WelcometothefirstissueofVolume4ofthe EngineeringQuarterly, anewsletterpublished fourtimesayearby theUniversityofMary SchoolofEngineering.
Initwetrytoincludearticlesfromeachofthe fiveengineeringmajorsthatwecurrentlyoffer oncampus:ElectricalEngineering,MechanicalEngineering,CivilEngineering,Computer Science,andConstructionManagement.
Wereportonitemsandeventsofinterest toengineeringstudents,engineeringcompanies,andnowalumniofourengineeringprogram.Youwillreadaboutourserviceandoutreachactivitiesinthecommunity,thescholarshipsourstudentshavebeenawarded,descriptionsoftheinternshipsourstudentshave workedatoverthesummer,guestspeakers thathavecomeinandenlightenedus,and evenassignmentproblemsandprojectsthat ourstudentshavecompletedaspartoftheir coursework.Wehopethatyouwillenjoyrevisitingsomeoftheproblemsthatyouhadto solvebackwhenyouwerestudyingforyour ownengineeringdegree–oratleastyouwill enjoythefactthatyoudon’thavetosolve them!
TheintendedaudienceoftheEngineering Quarterlyisengineers,engineeringstudents, engineeringalumni,futureengineeringstudents,andpeopleworkinginfieldsclosely relatedtoengineeringsuchasscience,computing,andmathematics.Enjoy!
Dr.TerryPilling DeanofEngineering
SUMMER INTERNSHIPS
Manyofourengineeringstudentswhoare Sophomorelevelandabovehaveinternships eachsummerandtheyreturnwithmanygreat storiesofthefunandinterestingthingsthey didwhileworkingatcompaniesandfirms. Herearesomeoftheirstories.
MeganAchbach internedintheSouth DakotaOfficeof theStateEngineer.
“Mymainresponsibilitiesweretoassisttheprojectengineersduringmeetingswiththearchitectandcontractors andtomaintainthe projectrecords.Ireallyenjoyedmytime thereasIworkedonagreatteamandstayed busy.Thecoolestthingthathappenedwas
MaraDalton internedatCOREConsultants,aprofessionalservicesfirm inEnglewood,ColoradoofferingCivil Engineering,Natural ResourcesandLandSurveyingservices.“I wasabletodabbleinmanythingsatthefirm, butmyprimaryresponsibilitywassheetsetup forwater,sanitary,andstormplansforavarietyofprojects.Iwasalsoabletolaysanitary servicesinCivil3D,updateandcreatewater services,aswellasshiftroadsandotherelementsinthe2Dlinework.Ireallyenjoyed learningwhatthe‘realworld’ofCivilEngineeringislikeandthoroughlyenjoyedthe companycultureandcommunity.Experiencingsitevisits,clientmeetings,CADtrainings, andworkpartieswasalsoveryfun!”
KolbeRaiche owned andoperatedadeck buildingbusinessin upperMichiganthis summercalled The DeckDudes.“Runningthisbusinessallowedmetolearn abouttheconstructionmanagementprocessonaverysmall scale.Inadditiontomanagingthefinancial sideofthebusinessandensuringprofitability,Iwasalsoresponsiblefordesigningand buildingthedecks.Iwouldtakesoiltests, calculateloads,andthenpayaprofessional engineertostampmydrawings.Tohelpbuild thedecks,Ihiredsomeofmyfriendsfrom highschoolwhichwasatonoffun.This summer,thecompanytripledinrevenueto about$100,000grosswhichallowedmeto seethewholepictureofconstructionmanagement.Thecoolestpartofmysummerwas re-buildinga1200squarefootdeckwhich hadbeencompromisedbyfrostheave.
PrestonOwens internedandthissummerataconstruction companydoingframing.“Imade15dollarsanhourandIwas assignedtoallkinds ofjobs,Icutwood,I nailedstuds,Ibuild dormers,Ibuiltdoorways,Iwaskindof allovertheplace.HonestlyIlikedthisjobit wasveryphysicallydemandingandIalways feltproductive.Ialsohadtheopportunityto learnmanythings,thisjobwasoverallagreat summerjob.Iwouldn’tsaythatanythingcool happenedbutsomethingstressfulhappened, thecranewasloweringatrussintoplaceandit droppeditontherestoftheroofandknocked alltheothertrussesover.”
PaigeLang interned atAPEXEngineeringGroupinBismarck,ND.“Iwasin theWaterResources departmentworking onprojectsthatincludedstormsewer designandpipeextensions.Ienjoyed thisinternshipsomuch.Iworkedwithsome amazingpeoplewhotaughtmeagreatdeal aboutdifferentengineeringsoftware,thebiddingprocess,andhowtheyacquirejobs.One coolthingIdidduringmyinternshipwastour theForterraconcreteplant.Thebestpartof theinternshipishavingtheabilitytocontinue workingduringtheschoolyear.”
JohnSoupir worked atCrusoeEnergy SystemsinWillistonND.“Iworked ontestequipment development,and cryptominerrepair anddeployment.I figuredouthowto buildanimproved versionofsomeexpensivecryptominertestequipmentusing scrapparts.ItwasagreattimeandIplanon returningnextsummer.”
ColeKitzenberg workedatArmacost TraneinBillings, MT,oneoftheleadingdevelopersand sellersofairconditioningandheating productsintheworld. “Iworkedasamechanicalengineering intern.Thefirstthree weekswereallaboutlearningabouttherefrigerationcycleandthephysicsinvolvedin it.Theythenhadmeselectingunitsforcustomersbasedonspecifiedneedandgenerating proposalsandsubmittals.Ihelpedinstalland setuprooftopunitsandhelpedwithcontrol wiring.”
WillBlewett worked atAdvancedengineeringandenvironmentalservices (AE2S)asResident ProjectRepresentative(RPR).“Loved it!Iwasabletowork onawatersupply projectthatisonce inalifetime.ItistheRedRivervalleywater supply,takingwaterfromtheMissouriand pumpingintotheCheyenneRiver.Thiswill helpprovidewaterfor2/3ofEasternND.”
IsaiahBitz worked atBraunIntertecin Bismarckthispast summer.“Someof thethingsthatIgot todoincluded:Lab testingsoilandconcretesamples(including:gradations, proctors,andcompressiontests),field testingsoilforcompactionandmoisturecontentwithnucleardensitygage,fieldtesting concreteforslump,aircontent,unitweight, temperature,andcylindercasting.Ithought thesethingsprovidedgoodexperienceforme tofurtherbuildmyunderstandinginsomeof theareasofcivilengineering.”
JamesJurek started aninternshipatBobcat,inBismarck, thissummer.“I willbeworking therethroughthefall semester.Iamadesignengineercoop ontheattachments team,andmyresponsibilitiessofarhaveconsistedofsustaining andnewproductdevelopmentprojectsforour currentproducts.Istartedoutbyrevisingalot ofengineeringdrawingstomakechangesrequestedbymanufacturing–smallthingslike aredesignedstepormovingaweld,andI’ve movedintodoingmoreinvolvedworklike designingandtestingnewmountingbrackets touseanattachmentonanewmachinewe willbeselling.MostrecentlyI’vebeendoing afinalevaluationofatwonewsnowblowers forourcompacttractors,beforetheygooffto beginproduction.”
JohnNauertz worked forHoustonEngineeringinBismarck asaSurveyingIntern. “Mymainresponsibilitieswereassisting inconstructionsurveys,doingcontinuoustopographysurveys,andassistingin droneflights.ThepeopleIworkedwithwere greatandIlearnedalotaboutthenecessity ofanaccuratesurveyforasuccessfulproject. OnefunthingthathappenedwasIgottosee alandfillmadethatwilllastforthenextsixty years.”
CaseyMack worked fortheCityofMandanUtilitiesDepartment.“Mymaindutiesweretoflush,repair,andpumpfire hydrants.Ontopof thosetasks,Iwas alsocalleduponto helpwithallotheraspectsoftheUtilities departmentincluding hangingandrepairingstreetlights,jettingand repairingsewerlines,maintainingandcleaningsewerliftstations,andrepairingwater mainlines.Therewerealotmoresmaller tasksthathelpedtheCityofMandanoperate
smoothly.IenjoyedmysummerjobbecauseI enjoyedbeingaroundtheguysIworkedwith andIfeltthatIwasdoinggood,important work.OneofthecoolestthingsIgottoexperiencewereallofthesuppliersthatcameout andpitchustheirnewproducts;fromstateof theartVacuumtruckstosmallpipefittings. Itwascooltoseealloftheengineeringand conceptsineachitem.”
DavidAtelbauers workedatAE2S(AdvancedEngineering andEnvironmental Services).“Iworked fortheBismarckoffice,butIwassentto theprojectinBeach, NDandParshall,ND. Mymainresponsibilitiesincludedreportingtotheprojectmanager,constructionobservationsandmakingdetailedreports.Itwas anamazingacademicandlifeexperiencefor me.AlmosteverydayIlearnedsomething new,eitheroutinthefieldorfrommysupervisor,whoisaProfessionalEngineerand helpedmealotthroughouttheinternship. Reallycoolwasthewholeexperienceingeneral.LearningfromProfessionalEngineers gavemeextramotivationtoonedaybecome PEmyself.Overall,itwasanamazingexperience,andIwasverygratefultoworkfor AE2S.”
BenWilson worked asanestimatorand projectmanagement internatCapitalCity ConstructioninBismarck.“Istartedoff byreviewingshop drawingsofallsorts, rangingfromsteel structuraldrawingsto doorandhardwaresubmittals.Ialsohelped estimateandmanagemulti-milliondollar projectsandkeepthemonschedule.Icommunicatedwithdozensofcontractorstohelp withprogressonnewandremodelprojects. Itwasanawesomeexperiencethatgavemea greatadvantageinthehiringmarket,Ilearned somuch.”
DerekFaul worked attheBobcatAccelerationCenterin Bismarckthissummer.“IdidPrototypeDesignandDevelopmentforLoadersandExcavators.I haveenjoyedworkingwithBobcat, goodpeopleanda greatwork/learningenvironment.Onething thattrulyamazedmethissummerwascost reductionprojects.Asavingsofafewdollars onasinglepart,canresultinaverylargesum ofmoneysavedonaproductionscale.”
CaseyAnderson workedconstruction thissummer.“Idid undergroundwork involvingexcavating, andIspentalotof timelookingatplans, determininggrade, andinstallingundergroundpipe.”
CAREER &INTERNSHIP FAIR
EachyearinthefalltheUniversityof MaryOfficeofCareerServicesinvitescompaniestocometocampusandspeaktoour studentsataninternshipfair.Thisyearthere wereanumberofengineeringcompanieswho attended.Thisisagreatopportunityforour studentstoseethemanyopportunitiesinthe areaandtoapplyforinternships,co-ops,and careerswiththesegreatcompanies.Severalof ouralumniwerehererepresentingtheircompanies(seethephotosonthelastpage!) www.apexenggroup.com
ApexEngineeringGroupprovidesconsulting servicesindrinkingwater,wastewater,waterresources,transportation,municipal,and electricalengineeringandlandsurveyingto theregion.Ourstaffhasapassionforprovidingengineeringsolutionsandbelievesit’s onlythebestsolutionifit’salsothebestexperience.Greatexperienceshappenbybeing truetoourcorevalues–listening,trusting, andworkingtogether–beliefsthatmakelife easierforourclients,thecommunity,andour employees.
AvailablePositions:CivilEngineeringInternship www.barr.com
Barrisaconsultingcompanythatintegrates engineeringandenvironmentalexpertiseto helpclientsdevelop,manage,process,andrestorenaturalresourcesacrossNorthAmerica andaroundtheworld.Wehavebeenemployeeownedsince1996andtraceourorigins totheearly1900s.Today,wehaveover800 employeesacrosstheU.S.andCanadawho workwithclientsinthemining,power,fuels, publicandmanufacturingsectors,aswellas attorneys,developers,andotherswithcomplexproblems.Pleasevisitourwebsiteto viewafulllistingofouravailablepositions andtoapplyonline.
www.bartwest.com
Ifyou’relookingforagreatplacetolaunch yourcareer,checkoutBartlett&West.
Bartlett&Westservesavarietyofclients withengineeringandtechnologydrivenser-
vicesacrosstheMidwest.
AvailablePositions:ApplicationDeveloper Co-op,BusinessSystemsCo-op,Information TechnologyCo-op
www.braunintertec.com
BraunIntertecisa100%employee-owned award-winningconsultingfirmoffering geotechnicalenvironmentalandtestingsolutionsintheprivateandpublicsectors. Foundedin1957,thefirmnowhasover30 officeslocatedacrossstatesintheMidwest andTexasandhasconsistentlybeenrecognizedasaTopWorkplacebyStarTribune andaBestPlacestoWorkbyMinneapolis/St. PaulBusinessJournal.Wearecommittedto providingachallengingandrewardingenvironmentthatencouragesemployeestomake fulluseoftheirknowledge,skills,andabilities.OurdedicationtobetheEmployerof Choiceisinstrumentalinachievingourgoal ofbecomingtheConsultantofChoice.
AvailablePositions:2022CivilEngineering andConstructionMaterialsTesting6-month Co-op(Bismarck)
www.hdrinc.com
HDRpartnerswithclientstoshapecommunitiesandpushtheboundariesofwhat’spossible.FromoursevenofficesacrossSouth Dakota,NorthDakotaandWyoming,we provideengineering,environmental,rightof-wayandconstructionservicestocommunities,creatingafoundationforprogress.Our multidisciplinaryteamsincludescientists, economists,builders,analysts,andartists.We workwithclientstoidentifyandcraftunique solutionsfortheeverydayneedslikesafe roadwaysandcleandrinkingwater.Theexpertiseweprovideisbackedbynearly10,000 employees,inmorethan200locationsaround theworld–andcounting.
AvailablePositions:EIT,Intern
vicesandgrewourcompanybydeveloping businessesaroundourexpertise.Today,MDU Resourcesisamultibillion-dollarcorporation withoperations,customers,andemployees acrossthecountry.Wehavemorethan13,000 employeesduringpeakconstructionseason andareauthorizedtoconductbusinessin44 states.MDUResourcesisthelargestpubliclytradedcompanyheadquarteredinNorth Dakota.Ourstockhastradedsince1948underthesymbolMDUontheNewYorkStock Exchange. www.mooreengineeringinc.com
MooreEngineeringisa100%employeeownedCivilEngineeringandLandSurveying firmwithlocationsthroughoutNorthDakota andMinnesota.
AvailablePositions:GraduateEngineer,RPR (SummerIntern) www.nisc.coop
www.bobcat.com/students
Morethan60yearsago,ourfoundersrocked theequipmentindustrybyinventingthefirst compactmachineandtransformingtheway theworldworks.Sincethen,we’venever stoppedbreakingtherulesandre-imagining whatcouldbe.Whileothersfollowourlead, ourteamsarefocusedonwhat’snext,busy creatingthevisionandthetoolsoftomorrow. Powerful,efficientproducts.Intelligent,connectedtechnologies.Innovativesolutionsthat revolutionizeonceagainhowworkgetsdone. AtBobcat,itispossibletochangetheworld. Joinusandhelpshapewhattomorrowwill be,rightnow.
AvailablePositions:EngineeringCo-op, ProductManagementCo-opandMore!
www.kljeng.com
AtKLJ,weloveengineering,movingforward,andbringingideastolife.Ourwork ismorethanaproject,it’salong-termsolutionforthecommunitiesinwhichwelive andwork.Wearecommittedtoprovidingan exceptionalexperiencetoourcustomers–everyproject,everytime.Were-imaginewhat projectscanbethroughinnovativeplanning, design,andsupportofinfrastructureprojects ofallshapesandsizes.Joinourteamand re-imaginewhatyourcareercanbe.
AvailablePositions:CivilEngineerInternshipTransportation,Water,Site,Structural,EngineerinTrainingI-Transportation,Water,Site,Traffic,Structural,SeniorEngineer (Structural-Building,Structural-Bridge, Civil-TransportationandWaterResources)
Areyoureadytoloveyourjobandtheplace youwork?Forover50years,NationalInformationSolutionsCooperative(NISC)has workedtodeveloptechnologysolutionsfor ourmorethan840Members(mainlyutility andtelecommunicationcooperatives)tohelp themoperateefficientlyandservetheircommunities.NISCisanindustryleaderprovidingadvanced,integratedITsolutionsforconsumerandsubscriberbilling,accounting,engineering&operations,aswellasmanyother leading-edgeITsolutions.Weareownedby theMembersweserve,andwearenotonly passionateaboutimprovingthelivesofour members,butalsoimprovingthelivesofour employees. www.dot.nd.gov
www.doosandigitalinnovation.com/en/ DoosanDigitalInnovationAmerica,LLC (DDIA)istheprimaryITsharedservice providerfortheDoosanaffiliatesinNorth America.Theircustomerportfolioincludes DoosanFuelCelllocatedinSouthWindsor, CTandDoosanBobcatCompanylocatedin WestFargo,ND.DDIAistheNorthAmerican presenceoftheSouthKoreanbasedDoosan DigitalInnovationentity.DDIAaspiresto providecost-effectivetacticalsupportand businessanalystexpertisetoourcustomers. Theorganizationiscomprisedofthreeteams whoarefocusedoninfrastructuresupport, operationssupportandapplicationsdelivery. Othercompanyemployeesincludebusiness analystswithstrongtiestotheDoosanbusinessunitswesupport.
www.mdu.com
MDUResourcesisBuildingaStrongAmerica.Astronginfrastructureistheheartofour economy.Itisthenaturalgasandelectricitythatpowerbusiness,industryandourdaily lives.Itisthepipesandwiresthatconnectour homes,factories,officesandstorestobring themtolife.Itisthetransportationnetwork ofroads,highwaysandairportsthatkeepsour economymoving.Infrastructureisourbusiness.Weprovideessentialproductsandservicesthroughourtwolinesofbusiness:regulatedenergydeliveryandconstructionmaterialsandservices.Ourcompanywasfounded in1924asasmallelectricutilityservinga handfuloffarmcommunitiesontheborder ofMontanaandNorthDakota.Werealized earlythevalueofdeliveringavarietyofser-
OriginallycalledtheStateHighwayDepartment,theNorthDakotaDepartmentofTransportation(NDDOT)wasestablishedin1917. TheNDDOTisaninnovativeandprogressive organizationthathasagreatteamofemployeesthatworkhardacrossthestatetocarryout theDepartment’smissiontosafelymovepeopleandgoods.TheNDDOTstrivestobuild andmaintainanefficienttransportationsystemconsistingofabout8,518milesofroadwayand4,858bridges.Itoverseesthedevelopmentofsurfacetransportationincluding highways,bridges,rail,transit,pedestrianand bicyclepathsacrossthestate.Annually,the Departmentprocessesover1,000,000vehicle registrationsandservesover500,000licensed driversatbranchofficeslocatedacrossthe state.TheNDDOT’sCentralOfficeislocated ontheNorthDakotaStateCapitolGroundsin BismarckandhaseightDistrictOfficesacross thestateinBismarck,DevilsLake,Dickinson,Fargo,GrandForks,Minot,ValleyCity
andWilliston.
AvailablePositions:TransportationEngineer, EngineeringTechnician,EngineeringTechnicianIntern
www.steffes.com
Steffesisasteelfabricationandelectricalservicesmanufacturerservingdiverseindustries includingoilandgas,electricthermalstorage,andcontractmanufacturing.Weuselean operatingprinciplestoreducewasteandincreasecustomervalue.Engineeringteamsat Steffeshaveextensiveexperienceintheindustriestheyserveandaccesstothelatest technologyincludingrobots,parametric3D modeling,mechanicalsystems,electricalsystems,toolanddie,hydraulicsandpneumatics.Wetakeprideinthequalityofourproductsandarecommittedtofosteringaculture ofinnovation.Employeedevelopmentisatop priority,andourcompanyculturepromotes mentorship,training,andeducationthrough bothinternaldevelopmentprogramsandprofessionaldevelopmentreimbursementtoensureweareinvestinginthefutureofthecompanybyinvestinginourteam.
AvailablePositions:ManufacturingEngineer, ManufacturingEngineerIntern,DesignEngineer,DesignEngineerIntern,SupplyChain Intern,ContinuousImprovementSpecialist, QualityTechnician,TechSupportTechnician, ProductionPlanner www.nacoal.com
TheNorthAmericanCoalCorporationmines andsuppliesligniteprimarilyasafuelfor powergenerationandprovidesvalue-added miningservicesforothernaturalresources companies.AsasubsidiaryofNACCOIndustries,Inc.(NYSE:NC),NorthAmerican Coalandaffiliatedbusinessesoperateseven surfacecoalminesintheUnitedStates,primarilyinNorthDakota,Texas,Mississippi, andLouisiana.Ouremployeesworkinareas ofconstructionscience,engineering,biology, environmentalscience,business,managementandotherscienceandtechnologyfields. Wegeneratelow-costelectricitytoourpower plantcustomersusingclean,efficient,andenvironmentallyfriendlytechnologies.In2019, wedelivered34.6milliontonsofcoaland continuetoprovidedraglineminingservices forindependentlyownedlimerockquarries inFlorida.
AvailablePositions:EngineerInternship,GeologyInternship,InformationTechnology andSystemsInternship,MechanicalEngineer/AutoCADInternship,SurveyorInternship titanmachinery.com TitanMachineryInc.,foundedin1980and
headquarteredinWestFargo,NorthDakota, ownsandoperatesanetworkoffullserviceagriculturalandconstructionequipment dealerlocationsinNorthAmericaandEurope.ThenetworkconsistsofUSlocations inColorado,Iowa,Minnesota,Montana,Nebraska,NorthDakota,SouthDakota,WisconsinandWyominganditsEuropeanstoresare locatedinBulgaria,Germany,Romania,SerbiaandUkraine.TheTitanMachinerylocationsrepresentoneormoreoftheCNHIndustrialBrands,includingCaseIH,NewHolland Agriculture,CaseConstruction,NewHolland Construction,andCNHIndustrialCapital.
PROBLEMSTOTRY
Herearesomeproblemsfromourcourses thissemesterthatyoumightliketotry.The solutionscanbefoundattheendofthisissue.
(b) Thendothisbyhandusingthevector loopmethod.
(c) Implementthesolutionyouobtaininpart binaCprogramsothatyoucouldsolve foranyfour-barlinkageofanysetof linklengths.
ENGINEERING ECONOMY QUIZ ByANTHONYWALDENMAIER
ENR460EngineeringEconomyisaclass dedicatedtotheunderstandingofcostimplicationsforEngineeringProjects.Consider buyingacar...Onecouldpayalotofmoney forabrand-newcarwithfewerfuturecosts. Onecouldbuyagentlyusedcarwhichwill costslessinitially,butitwillrequiremorefuturecostsinmaintenanceduetoage.Or,one couldbyanold“clunker”thatwillbevery cheapatfirst,butwillrequiremanyimmediaterepairsandservicing.Whichoptionwill actuallybethecheapestfora5,10,or15year ownershipperiod?
WriteaCprogramtocalculatetheinverse ofa 3 × 3 matrix.Makeitsothattheoutput lookssimilartothatofMatlaborOctave:
Forthisquiz,studentsareaskedtocalculatetheEquivalentUniformAnnualWorth (EUAW)for3trafficintersectionalternatives: aroundabout,standardtrafficlights,andregularsignage.Costsweregeneratedprimarily fromastudyconductedbytheVirginiaDepartmentofTransportationcomparingroundaboutstotrafficlights.Roundaboutsarebecomingmoreandmorepopularduetoloweredtraveldelaysandstoppingtimes.However,theyrequireaverylargeinitialinvestment.Asseenintheproblembelow,thecurrentintersectiondesignisinadequateforthe increasedtrafficflowinthearea.Basedon thebestdataavailable,whichalternativewill costthecitytheleastmoneyoverthenext25 years?
Thisproblemalsoincorporatesasocietal impact,whereinthepublic’sinputandresearchmayimpacttheoverallselectionofthe “best”alternative.
CIRCUITS I PROBLEM ByNANCYKELLY
UserepeatedapplicationsofOhm’slaw, KVL,andKCLtoeventuallyfindthevalues of Vs and Is inthecircuitshowninthefigure.
DESIGNOF MACHINERY PROBLEM ByJAMESCARRICO
Afour-barlinkagehasthefollowinglink lengths:2in,5in,6in,and4in.The4inlinkis groundedhorizontallyandisjoinedtothe2in linkontheleftandthe6inlinkontheright. Giventhatthe2inlinkisoriented 25◦ offof thehorizontal.Findthetwopossibleconfigurationsoftheothertwolinksandtheangles theymakewiththehorizontal.
(a) DothisoncegraphicallyusingaCAD packagelikeSolvespace.
Acityisconsidering3alternativesto changeaproblematicroadintersectionin town,whichhasbeensubjecttoexcessively highnumbersoftrafficaccidentsinthelast 2yearssinceanewhighschoolwasopened. Thecityhasresearchpotentialcostsfora roundabout,installingtrafficlights,andreevaluatonandplacementoftrafficsigns.Consideringanationalaverageinterestrateof 4.5%fortraffic-relatedinfrastructureanda planneddesignlifeof25years,performthe costsanalysiscalculationsbasedonthedata below.
(a) (36points)DeterminetheEquivalent UniformAnnualWorth(EUAW)of eachalternative.
(b) (5points)Decidewhichalternativeisthe mostcost-effectiveandexplainwhy.
(c) (10points)Duringtheresearchphase,the cityexploredsocietalimpactsofeach alternativeacrosssimilarintersections acrosstheU.S.andconductedasurvey ofthelocalresidentsanddrivers.Based onresearchandfeedback,thecitycreatedthefollowingtablewhichwillgenerateamultipliertoapplytotheEUAW. Note:alowernumberindicatesalesser negativeimpactasviewedbythepublic
Aesthetics Noise (50%) (20%) (15%) Roundabout 3 3 4
4 5 6
6 5 6 Construction Multiplier (15%) Roundabout 9 4.05 TrafficLight 3 4.35
1 5.05
DeterminetheEUAWofeachprojectbased onthesocietalimpacts:
(d) (4points)Basedonthesocietalimpact multiplier,whichalternativewillbethe mostcosteffectiveconsidering“social costs”?
(e) (6Bonuspoints)ShowthattheEUACof the$5,000recurringrecalibrationfee appliesfor25years
(f) (4BonusPoints)Showtheworkforthe RoundaboutmultiplierfromProblem (c)
dominatedoverwisdomthistimeandthestudentteambeatthefacultyteam55to48. However9ofthefacultypointscamefroma littleknownrulethat,attheendofthegame, youget10pointsformakingabasketfrom halfcourt.Theshotwasmissedbutthefacultymemberwasfouled,leadingtoanother littleknowrulethatonthe10pointshotyou get10freethrowsifyouarefouled.Thefacultymembermade9ofthe10freethrows bringingtheirfinalscoreto48.Nexttime we’llbeat’em!
ELECTRONIC HISTORY ByTERRYPILLING
Asanyengineerorscientistknows,the electronisthefundamentalparticlethatisresponsiblefortheorbitalstructureofatoms andtheresultingchemistryoftheelements. Electronsareresponsibleforelectricityand arethereasonforallofourelectricaland electronictechnologyunderlyingourmodern world.
Theelectronisatiny,negativelycharged, particlewhichnormallyorbitsthenucleusof atomsbutwhichcanbeeasilyliberatedfrom theatomandmadetoflowthroughmaterials suchasmetalswhenthereisavoltagegradientappliedtothemetal.Itisourmanipulationofthesevoltagegradientsinmaterials thatallowsustousetheflowofelectronstodo work.Theresultisourelectricpowergrids, ourelectronicsdevices,theappliancesweuse onadailybasis,andliterallyeverythingonthe planetthatplugsintothewallorhasabattery insideit.
InthisarticleIwanttoshowyouaninterestingexperimentthatwasperformedin1916 tomeasurethemassoftheelectron.
Atthattimewehadlearnedtocontrol electronsintheformofelectricityanduse itforpoweringourcitiesandcommunicating usingelectromagneticradiationsuchasradio andtelephone,however,wedidn’tunderstand everythingaboutthepropertiesoftheelectron itself.Thepreviouscenturyhaddiscovered strangebehaviorssuchastheso-called‘photoelectriceffect’whichledtothestrangelaws ofQuantumMechanics(andalsoledtoAlbert EinsteinbeingawardedaNobelPrizein1921 forhis1905theoreticalexplanationoftheeffectbasedonthequantizationoflight).
Theelectricchargeonanelectronwas
OnMonday,October4that7pm,theannualCaptainsvs.Crewbasketballgametook place.Thisfaculty/staffvs.studentbasketball gameisabuddingtraditionofourhomecomingweek.MechanicalEngineeringprofessor AnthonyGarciaparticipatedasaplayeronthe faculty/staffteam.ThepictureshowsProf. Garciadefendingagainstengineeringstudent NathanDesMarais.Itmaynotbewellknown amongourengineeringstudentsbutbothEric andAnthonyGarciahaveplayedbasketball onteamsfromaveryyoungageandboth areveryskilledplayers.Unfortunately,youth
Theelectronwasthefirstsubatomicparticletobediscovered.Itwasdiscoveredby BritishphysicistJ.J.Thompsonin1897using cathoderaytubes(whichareessentiallythe oldstyletelevisiontubes).Thompsonthen proceededtomeasuretheratioofthecharge tothemassofanelectronandwasawarded theNobelprizein1906.Knowingthecharge tomassratiomeantthatallweneededwas aseparatemeasurementofeitherthecharge orthemassandwecouldthenusetheknown chargetomassratiotofindtheother.The thingthatmakesthissocomplicatedisthefact thatthechargeandthemassoftheelectronare sovanishinglysmallthatitwouldtakesome cleverengineeringtoinventamethodtomeasureit.However,thatisexactlywhatourscientificforefathersmanagedtodo.Let’ssee howtheydidit.
measuredbyaclever methodin1909by AmericanexperimentalphysicistRobert MillikanandhisgraduatestudentHarvey Fletcher.Theystudiedthemotionoftiny chargedoildropletsin electricfieldsandnoticedapatterninthe chargesonthedroplets inthattheywerealwaysexactmultiplesofa specificnumber.
MillikanandEinstein
Millikan’sexperimentusedacanisterwith metalelectrodesonthetopandbottom.The electricfieldbetweentheelectrodescouldbe adjustedbymeansofdialsandtherewasa windowonthesideof thecanisterwithamicroscopeattachedso thattheexperimenter couldstudythemotionoftinyoildroplets insideashedialedtheelectricfieldupand down.Whentheelectricfieldwasjustthe rightvaluetheoildropletswouldfloatthere, suspendedagainstgravity.Knowingthedensityofoil,andmeasuringthevolumeofeach dropletbyobservingthemthroughthemicroscope(equippedwithruledlinesonthewindow),enabledhimtocalculatethemassof theoildroplet.Hencethefactthat,forasuspendeddroplet,theelectricforceactingupwardwasexactlybalancingthegravitational forcedownward,Millikancouldcalculate theelectricchargeofthedroplet.Repeating theexperimentformanydroplets,Millikan showedthattheresultscouldbeexplained ifthechargeonthedropletwasaninteger multipleofacommonvalue–whichisthereforethechargeofasingleelectron.Millikan wasawardedtheNobelPrizein1923forthis work.TheresultsofThompsonandofMillikanthereforegaveusboththechargeofan electronanditsmass:
me =9 109 × 10 31 kg
qe =1 602 × 10 19 C
Asallscientistsandengineersknow,itis notenoughtodojustoneexperimentandthen claimthetruthofyourfindings.Inorderto betakenasexperimentalfact,thesameresult mustbefoundinamultitudeof completely different experiments.Onlywhenresultsand predictionsbasedonthoseresultshavebeen independentlyverifiedbynumerousexperimentscanwestarttotakethemasfact.One oftheseindependentverificationsoccurredin 1916byachemicalengineernamedRichard Tolman.TolmanisoneofmyfavoritescientistsofalltimeandIhavecopiesofevery bookandpaperheeverwrote.Heneverwon aNobelprize,hewasnotparticularlyfamous, nordidhemakeanyparticularlyprofounddiscoveries.ThereasonIlikehimsomuchis thatheis fun!Hispapersaresomuchfunto read!Throughouthislifeheretainedthecuriosityofachildandthatexcitementisreadily apparentinhispapers.Ireallyenjoyspendinganeveningonceinawhilegoingthrough aTolmanpaperandrepeatingallofhiscalculations.WhenIeventuallygetbacktowriting
researchpapersIamgoingtotryandmake themasfuntoreadastheonesTolmanwrote.
andeventhemagneticeffectsofcarsdriving byonthestreetoutside!
TolmanwasborninWestNewton,Massachusettsandstudiedchemicalengineering atMIT.Hereceivedhisbachelor’sdegreein 1903andhisPh.D.in1910.In1922hejoined thefacultyoftheCaliforniaInstituteofTechnology,wherehebecameprofessorofphysicalchemistryandmathematicalphysicsand laterdeanofthegraduateschool.During WorldWarII,TolmanservedasscientificadvisortoGeneralLeslieGrovesontheManhattanProjectand,atthetimeofhisdeath,he waschiefadvisortoBernardBaruch,theU.S. representativetotheUnitedNationsAtomic EnergyCommission.Eachyear,thesouthernCaliforniasectionoftheAmericanChemicalSocietyhonorsTolmanbyawardingits TolmanMedal“inrecognitionofoutstanding contributionstochemistry.”
Betweentheyearsof1916and1923Tolmanandhisstudentsinventedanumberof coolandfunexperimentstomeasurethemass oftheelectron.Forexample,apaperbyTolmanandhisstudentThomasStewartin1916 whichwaspublishedinthejournal Physical Review,VolumeVIII,Number2,inAugust 1916.
Thearticleisinterestingfromanengineering pointofviewsincetheydescribeingreatdetailhowtheyconstructedtheirmachine.They evendetailhowtheyboltedthe2x4’stogether, howtheypressuregluedlayersofbirchveneertomakethespinningdisk,changingthe directionofthewoodgrainby45degreesin eachlayer,andthemanyclevermethodsthey hadtodeveloptoeliminatespuriousinterferingeffectssuchastheEarth’smagneticfield
Ifyouimagineametalbarfilledwithelectronsyouwouldexpectthatifweattached oneendofthebartoaspinninghub,like thecenterofabicyclewheel,andletitspin around,thenthecentrifugalforcewouldcause theelectronstomigratetotheotherendofthe barbecauseoftheirmass.Sincetheelectrons alsocarryelectriccharge,weshouldthenbe abletomeasuretheincreaseinchargeatthe endoftherodandcalculatehowmanyelectronsmigratedthere.Anothermethodwould betouseaspinningmetaldiskratherthana rod. Thefreeelectronsinthediskwouldmigrate totheouteredgeofthediskasitspinsand youcouldthenmeasurethevoltagedifferencebetweentheinnerandouteredgesof thedisktofigureouthowmanyofthemmigrated.However,althoughthisisaninterestingfirstidea,theyimmediatelyrealizedthat theeffectwouldbeextremelydifficulttomeasureduetotheverysmallmassoftheelectrons.Sotheyhadtocomeupwithamore clevermethodusingthesamebasicideas.Instead,theywrapwirearoundtheoutsideof adiskandthenspinthedisktohighspeed. Thiscausesthefreeelectronsinthewiregain momentumastheybegintomovearoundand aroundwiththewire.Theexperimentersthen stopthedisksuddenly.Theelectrons,being free,continuetomoveinthedirectionoftheir originalmomentumuntiltheresistanceofthe wireeventuallystopsthem.Thiscontinued forwardmotioncausesaspikeinthevoltage acrosstheendsofthewiresimilartotheway thatdischargingacapacitorthrougharesistor willcauseaspikeinavoltmeteracrosstheresistorforashorttimeuntilthecurrentstops
flowing.Lateron,Tolmancontinuedtodevisenewmethodsformeasuringthemassof theelectronandwroteaboutthoseinsubsequentpapers.Theyareallinterestingdevices thatanyofuscouldbuildourselvesforfunif wewantedto.Herearesomediagramsfrom apaperhewrotein1923
andherearetheresultsofhismeasurements
Let’susetheknownvaluefortheelectric charge, e,andseewhathismeasurementsgive forthemass.Hesaysthatinfreespacehis measurementgives
m/e =5 66 × 10 8 andtheunitsaregramsper abcoulomb.An abcoulombisequalto10Coulombs.InKilogramsperCoulombthenumberhegotis
m/e =5 66 × 10 12 kg/C andusingtheknownvalueoftheelectric chargewefindthat
m =(1 602 × 10 19C)(5 66 × 10 12kg/C) =9 067 × 10 31 kg
whichisprettyclosetothemodernvalueof me =9 109 × 10 31 kg.
Itisfuntoreadscientificpapersfromthe earlypartoflastcentury.Backthentherewas nosuchthingaselectronics,printedcircuit boards,3dprinting,etc.,andsotheexperimentstheydescribeareonesthatyoucould buildinyourgarageoutofbicyclepartsand 2x4’sifyouwantedto.Itisneatthatimportantandprofoundresultslikethemassorthe chargeofanelectroncanbemeasuredinyour garagewithsomecleverengineeringandabit ofmath.
