Conference Session

Learning and Assessment II

Collection

2012 ASEE Annual Conference & Exposition

Authors

Amir Karimi, University of Texas, San Antonio; Randall D. Manteufel, University of Texas, San Antonio

Tagged Divisions

Mechanical Engineering

students to show why enthalpy remains constant for a process involvingfluid flow in an expansion valve. They also had to show why the value of specific entropyincreases during the process. As a minimum, students had to state the logical assumptions thatthe process is a steady state, it involves no transfer of power, and kinetic energy and potentialenergy effects are negligible. They also had to show the following steps:dmcv = m& i − m& e or m& i = m& e = m& dtdEcv ⎛ V2 ⎞ ⎛ V2 ⎞ = Q& cv − W& cv + m& i ⎜ hi + i + gzi ⎟ − m& e ⎜ he + e + gz e ⎟ dt ⎜ 2 ⎟ ⎜ 2

Conference Session

Laboratory Innovations

Collection

2012 ASEE Annual Conference & Exposition

Authors

Awlad Hossain, Eastern Washington University; Hani Serhal Saad, Eastern Washington University; Martin W. Weiser, Eastern Washington University

Tagged Divisions

Mechanical Engineering

center of mass. Thisassumption can be later checked to see if it is valid.The cylinder is assumed to be at an initial temperature Ti and is then placed in still air at atemperature T∞. The coefficient of convection and surface area of the body are referred to as hand A, respectively. If the body is at a temperature T, then, the heat transfer Q due to convectionis given by Q = dU/dt = hA(T-Tinf) (2)where U is the total energy stored in the system. The temperature T obviously varies with time.The quantity Q can also be expressed in terms of the heat capacity C of the material. Indeed, bydefinition C is Q C

Conference Session

Learning and Assessment III

Collection

2012 ASEE Annual Conference & Exposition

Authors

Jenna L. Gorlewicz, Vanderbilt University; Robert James Webster III, Vanderbilt University

Tagged Divisions

Mechanical Engineering

assessed the normality of each student section’s data for each year. To do this, wecreated a quantile-quantile (Q-Q) plot for each student section, including both pre-test scores andlab quiz scores, resulting in a total of 8 plots. For simplicity, only one of the plots is shown inFigure 4, however, it is representative of the other plots obtained. Because this plot suggests alinear trend, we can infer that our data is approximately normally distributed, and thus, parametricstatistical tests, such as the t-test, are applicable in our subsequent analyses.Figure 4: A Q-Q plot from one student section assessing the normality of our data. The linearity ofthis plot suggests that the data follows an approximate normal distribution. Q-Q plots were

Conference Session

Outreach, Engagement, and Undergraduate Research

Collection

2012 ASEE Annual Conference & Exposition

Authors

Matthew A. Carr, U.S. Naval Academy; Jim Cowart, U.S. Naval Academy

Tagged Divisions

Mechanical Engineering

injection water drained from thecylinder tended to overflow the FWT and that the temperature in the FWT of one of Smeaton’sengine was 134oF.methodologyThe general model that applies to a heat engine operating a pump is shown in Fig. 6. Figure 6 - Pumping Engine Efficiency Relationships Page 25.1357.8The notation convention used herein is that “dotted” terms indicate the time rate of the extensivevariable. The fuel energy rate ( E ) is the product of the mass flow rate of the fuel ( m ) and itsheating value (HV). The thermal power ( Q s ) supplied to the cylinder is the product of the massflow rate of the steam ( m stm

Conference Session

Laboratory Innovations

Collection

2012 ASEE Annual Conference & Exposition

Authors

Steven O'Halloran, University of Portland; Matthew Rodrigues, University of Portland

Tagged Divisions

Mechanical Engineering

thermoelectric device (Type-T thermocouple)  Heater voltage, measured using a voltage divider (analog voltage input)  Load voltage, measured across variable resistor  Partial load voltage, measured across the 0.488Ω fixed resistor and used to calculate load current.In order to calculate efficiency using Equation (1), the input heat, Q in, and output power Pout,must be found. The input heat is found using the heater voltage and heater resistance as shownin Equation (2) below. (2)The heater voltage was measured by the data acquisition system and the heater resistance wasmeasured as 9.00Ω prior to testing.The power output was calculated using the

Conference Session

Learning and Assessment I

Collection

2012 ASEE Annual Conference & Exposition

Authors

Robert G. Ryan, California State University, Northridge

Tagged Divisions

Mechanical Engineering

lowest ratings were 2.20 and 2.30, for “Analysis” and Questions andAnswers”, respectively. Some of the analysis problems were related to how the input loads andrestraints were determined, rather than the use of the software itself. During the Q/A session,some groups had difficulty justifying the reasons for some of their decisions related to theiranalysis. It should also be noted that the high standard deviation for “Goals/Criteria” was due tothe lack of clarity in the purpose of the analysis (i.e. with respect to their optimization) by two ofthe groups. In summary, effectively using the material presented in this course is a challenge forour students, but while they clearly struggled on some issues, the projects provided a valuableexperience to

Conference Session

Simulations and Visualizations

Collection

2012 ASEE Annual Conference & Exposition

Authors

Nicholas Mark Randall, University of Southern Maine ; Mehrdaad Ghorashi P.E., University of Southern Maine

Tagged Divisions

Mechanical Engineering

statics course to explore the concept of equilibrium of a rigid body. In this way, mechanicalengineering students will gain an increased depth of understanding of the subject as well as someinsight about the application of the theories.2. Theoretical Analysis of Bending and Transverse LoadingIt is well-known that if a homogeneous, isotropic prismatic beam is subjected to a transversalshear force V, the resulting shear stress τ, induced in the beam can be obtained by10, (1) Page 25.395.3Where I is the cross-sectional moment of area, Q is the first moment of

Conference Session

Learning and Assessment I

Collection

2012 ASEE Annual Conference & Exposition

Authors

Sriram Sundararajan, Iowa State University

Tagged Divisions

Mechanical Engineering

) equations 1D&$&<=)/66"F.,-) "=,1D&%.?&) 2&%.-,)/,;)@",;#@1)/,) well as to analyze and .&(5$E7$!C@$=;BF$ interpret data (mechanical) 1D&"$&1.@/6)Q,"F6&;-&) .=:@"$&)M)L9A :7O :9L LBA ,A=>$K=9CLM$ 2&%@$.=$ 0&/%#$&0&,1)/,;) H@CJ8>=$;$K@8=I$ S/@"$&)MK9A :7O :7: OBA ;BOJ8=?B@8HOC:$CI$ .,%1$#0&,1/1.",).,)1D&) %.-,.3.@/,@&8)%1$&

Conference Session

Outreach, Engagement, and Undergraduate Research

Collection

2012 ASEE Annual Conference & Exposition

Authors

Natalie Barrett, Purdue University, West Lafayette

Tagged Divisions

Mechanical Engineering

the adiabatic process, the students were asked if the heat, Q, wasgreater for process 1. Although the acceptable selection ranged from 40% to 56% percent, only11% gave an acceptable response based upon the first law of thermodynamics. This implies thatalthough the students could get the correct answer, they could not give an acceptable reasonabout why it was correct. This could be because they lack conceptual understanding of the firstlaw, but not necessarily procedural understanding. In addition, Loverude and others (2002) showthat students did not consider the first law of thermodynamics when given a problem that neededthe first law to be answered correctly. Loverude and others questioned 36 thermal physicsstudents during two rounds of