Evaluation of STEM Engagement Activities on the Attitudes and Perceptions of Mechanical Engineering S-STEM Scholars.

Since 2009, the mechanical engineering (ME) scholarship-science technology engineering and mathematics (S-STEM) Program at the University of Maryland Baltimore County (UMBC) has provided financial support and program activities to ME undergraduate students aiming at improving their retention and graduation rates. The objective of this study is to identify program activities that were most effective to help students for improvements. Current ME S-STEM scholars were asked to complete a survey that measures their scientific efficacy, engineering identity, expectations, integration, and sense of belonging, as well as how program activities impact their attitudes and perceptions. Analyses of 36 collected surveys showed that scholars reported high levels of engineering identity, expectations, and sense of belonging. However, further improvements were needed to help students in achieving scientific efficacy and academic integration into the program. Results demonstrated that pro-active mentoring was the most effective method contributing to positive attitudes and perceptions. The implemented S-STEM research-related activities and internship were viewed favorably by the scholars in helping them establish their scientific efficacy and engineering identity, and understand their expectations and goals. Community building activities were considered helpful for them to integrate into campus life and improve their sense of belonging to the campus and program. Scholars identified mentoring, research related activities, internships, and social interaction with faculty and their peers as important factors for their retention and graduation. Although the sample size was small in the study, we believe that the cost-effective activities identified could be adopted by other institutions to further improve students' retention and graduation rates in engineering programs.

Theoretical simulation of temperature elevations in a joint wear simulator during rotations.

The objective of this study is to develop a theoretical model to simulate temperature fields in a joint simulator for various bearing conditions using finite element analyses. The frictional heat generation rate at the interface between a moving pin and a stationary base is modeled as a boundary heat source. Both the heat source and the pin are rotating on the base. We are able to conduct a theoretical study to show the feasibility of using the COMSOL software package to simulate heat transfer in a domain with moving components and a moving boundary source term. The finite element model for temperature changes agrees in general trends with experimental data. Heat conduction occurs primarily in the highly conductive base component, and high temperature elevation is confined to the vicinity of the interface in the pin. Thirty rotations of a polyethylene pin on a cobalt-chrome base for 60 s generate more than 2.26 °C in the temperature elevation from its initial temperature of 25 °C at the interface in a baseline model with a rotation frequency of 0.5 Hz. A higher heat generation rate is the direct result of a faster rotation frequency associated with intensity of exercise, and it results in doubling the temperature elevations when the frequency is increased by100%. Temperature elevations of more than 7.5 °C occur at the interface when the friction force is tripled from that in the baseline model. The theoretical modeling approach developed in this study can be used in the future to test different materials, different material compositions, and different heat generation rates at the interface under various body and environmental conditions.