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Turning is crucial for animals, particularly during predator–prey interactions and to avoid obstacles. For flying animals, turning consists of changes in (i) flight trajectory, or path of travel, and (ii) body orientation, or 3D angular position. Changes in flight trajectory can only be achieved by modulating aerodynamic forces relative to gravity. How birds coordinate aerodynamic force production relative to changes in body orientation during turns is key to understanding the control strategies used in avian maneuvering flight. We hypothesized that pigeons produce aerodynamic forces in a uniform direction relative to their bodies, requiring changes in body orientation to redirect those forces to turn. Using detailed 3D kinematics and body mass distributions, we examined net aerodynamic forces and body orientations in slowly flying pigeons (Columba livia) executing level 90° turns. The net aerodynamic force averaged over the downstroke was maintained in a fixed direction relative to the body throughout the turn, even though the body orientation of the birds varied substantially. Early in the turn, changes in body orientation primarily redirected the downstroke aerodynamic force, affecting the bird’s flight trajectory. Subsequently, the pigeon mainly reacquired the body orientation used in forward flight without affecting its flight trajectory. Surprisingly, the pigeon’s upstroke generated aerodynamic forces that were approximately 50% of those generated during the downstroke, nearly matching the relative upstroke forces produced by hummingbirds. Thus, pigeons achieve low speed turns much like helicopters, by using whole-body rotations to alter the direction of aerodynamic force production to change their flight trajectory.

Starting with the a-ha: An integrated introduction to solid and fluid mechanicsWe have developed an introduction to continuum mechanics for sophomore studentswithout any prior knowledge of mechanics. The essence of continuum mechanics, theinternal response of materials to external loading, is often obscured by the complexmathematics of its formulation. By building gradually from one- to two- and three-dimensional formulations, we are able to make the essence of the subject more accessibleto undergraduates. From this gradual development of ideas, with many illustrative real-world case studies, students develop both physical intuition for how solids and fluidsbehave, and the mathematical techniques needed to begin to describe this behavior. Atthe same time they gain a unique appreciation for the connections between solid and fluidmechanics. These connections are often only revealed to advanced undergraduates andgraduate students who elect to study continuum mechanics, when a curtain is pulled backto reveal the a-ha – the similarities between solids’ and fluids’ governing equations, andthe connections between their constitutive laws. In our approach, we start with this a-ha.Through this approach, students appreciate the behavior of engineering materials as aspectrum with Hookean solids at one extreme, and Newtonian fluids at another, withmany complex behaviors in between. This perspective is particularly valuable forstudents interested in biological applications, as the complex behaviors of biomaterialsare thus part of the spectrum of engineering material behavior from the beginning, ratherthan afterthoughts or exceptions to the rules made for more traditional materials. Ourapproach demonstrates the connections between solid and fluid mechanics, as well as thelarger mathematical issues shared by both fields, to students who have not yet takencourses in fluid mechanics and/or strength of materials. The context and foundationprovided by this educational strategy are available to students as they continue to studyeither solid or fluid mechanics, or specialize in the connections themselves by returningto a deeper study of the overarching field of continuum mechanics.A key aspect of our implementation is the integration of multiple case studies, involvingthe application of course material in relevant real-world situations from the design ofbiomedical devices to the construction of the Three Gorges Dam. In addition todemonstrating the utility of the modeling and analysis methods taught, these case studiesaddress ethical and societal issues. Like the continuum a-ha, these issues are introducedas a natural part of engineering mechanics from the very beginning, and our students’ability to appreciate and negotiate these issues continues to develop throughout theirsubsequent coursework.We describe the development and implementation of this approach at one institution, andhow we resolved the challenges involved in transferring the approach to a secondinstitution. We discuss several refinements to our methodology that resulted frombroadening our audience. Assessment results from over 10 years, at two institutions, areevaluated and interpreted.

This Complete Evidence-based Practice paper will focus on the design, implementation, and evaluation of a multidisciplinary introductory engineering course that integrates theory and hands-on practice around a theme of underwater robotics. The course is required for all students (including non-engineering majors) at a small liberal arts college and is the first engineering course for the majority of enrollees. The previous version of the course was a traditional lecture-based introduction to lumped element modeling of mechanical and electrical systems and modeling of signals using a Fourier analysis approach. The new version of the course covers most of the same technical content, although a Laplace transform approach has replaced the Fourier transform approach and a brief introduction to control theory has been added. Based on best practices in engineering education, the course design and implementation team has moved from the lecture model to a model that includes active learning (flipped classroom) tutorials and hands-on practicums. Students watch videos created by the instructors before the first tutorial session of the week, then come to tutorial to take both individual and team quizzes (similar to Team-Based Learning practices) and work with their teams on a short problem that provides real-world context for the content covered in the videos. The second tutorial session of the week is dedicated to context-rich problem solving with significant interaction between the instructors and students. Following the two tutorial sessions each week, students take part in a 2.5-hour practicum session where they experience the content in a hands-on environment, with most practicums focused on an aspect of the underwater robot. For example, the robot is placed in a water tank with a buoyancy “spring” attached and a chirp signal is input to the thruster to obtain a Bode plot response of the robot’s position versus thruster input frequency. Evaluation measures include a pre/post attitudinal survey regarding the usefulness of class content, intent to major in engineering, and understanding of the engineering profession and pre/post content tests from both the previous, lecture-based incarnation of the course, and the new version of the course. Results show significant increases in student learning, affective gains, perceived understanding of the field of engineering, and an erasure of a previous gender gap in course performance.

This paper will discuss the transition from a lecture-based multidisciplinary introductory engineering course to a revised version that integrates theory and hands-on practice around a theme of underwater robotics, including discussion of the design, implementation, and evaluation of the revised course. The course is required for all students (including non-engineering majors) at a small liberal arts college and is the first engineering course for the majority of enrollees. Final grades in the original lecture-based course showed a gender disparity in which male students outperformed female students that had persisted over the course of many offerings. By employing best practices in engineering education, with a special focus on inclusive teaching practices, the course was revised to a model that includes active learning (flipped classroom) tutorials and hands-on practicums. Students attend two tutorial sessions and one hands-on practicum session each week. Before the first tutorial session each week, students watch videos created by the instructors. Students take individual and team quizzes (following the procedure used in Team-Based Learning), which provide accountability for learning the course material. With the remaining time in the first tutorial of the week and the entirety of the second tutorial of the week, students work in small groups with significant student-instructor interaction on context-rich problems focused on real-world engineering applications. The students then take part in a 2.5-hour practicum session where they interacted with physical manifestations of the course content, largely focused around an underwater robot. For example, in one practicum the students placed their robot in a water tank with a buoyancy “spring” attached, then introduced a step input in motor force and measured the robot’s step response; they then used the output data to find the robot’s damping ratio and natural frequency. Mastery of course content was measured in both the original lecture-based course and the revised course via a pre/post content test; other evaluation measures included a pre/post attitudinal survey regarding the usefulness of class content, intent to major in engineering, and understanding of the engineering profession and student evaluations of teaching. The results show a significant increase in learning and affective gains for all students. Furthermore, the gender disparity in final course grades has disappeared in the revised course and there is no difference between the performance of male and female students on the pre/post content test.

Thin film structures of integrated circuits contain many polycrystalline materials. As circuit device dimensions are reduced to increase performance, typical feature sizes of associated polyerystalline structures are also reduced. The dimensions of those structures are approaching the size of grains, and the properties of polycrystalline materials at the level of grains and grain boundaries increasingly are determining circuit performing. In modeling these materials grain boundaries must therefore be modeled explicitly. For many problems of technological interest, such as hillock formation and electromigration in metal films, the consideration of several coupled physical phenomena (diffusion, stress, electric fields, thermal effects) is required. Efforts thus far to model coupled, physical phenomena in polycrystalline materials typically have been limited to simple grain geometries and analytically determined stresses. The motivation for this work is to create a general field formulation that will enable the treatment of arbitrary boundary value problems on polycrystalline domains. This is accomplished with the development of a detailed thermodynamic basis which reflects lattice-based mechanisms. Continuum level constitutive relations for vacancy flux and stress follow from the thermodynamics in a consistent manner. The system of equations which results from this treatment requires specialized numerical methods which are developed in this work. Several numerical examples provide test cases for the formulation and begin to address technologically relevant problems.

Each summer the Engineering Department at Harvey Mudd College (HMC) conducts Partners in Engineering Problem Solving (PEPS), a workshop for secondary school math and science teachers with the aim of introducing them to the design methodologies used in HMC’s freshman engineering course. That course, Introduction to Engineering Design, and the workshop use studio methods to teach design methodologies, team formation and dynamics, and project management. The five-day workshop brings together teachers from around the United States and immerses them into a hands-on design problem. The ultimate goal of the workshop is to empower educators to develop and apply methods of problem solving and engineering design to open-ended problems in their classrooms. Most of the attendees are selected from schools serving populations traditionally underrepresented in engineering. In addition to exposing the teachers to engineering design methods, the workshop serves to facilitate discussions on how best to attract students into engineering and the sciences. PEPS was originally developed as an extension of a program at Dartmouth College, and has been significantly modified to use the particular strengths available at HMC. An interesting aspect of PEPS has been its use by HMC faculty to conduct pedagogical experiments that have been later implemented in the college classroom. The workshop has been examined using formal assessment techniques and instruments and appears to be realizing its stated goals. For the past four years, Harvey Mudd College (HMC) has hosted a workshop for secondary school teachers of math and science. The primary purpose of the workshop is to offer the teachers an introduction to elements of engineering design in a way that will encourage them to incorporate engineering design projects into the high school curriculum. The workshop, Partners in Engineering Problem Solving (PEPS), begins with a hands-on design exercise, and culminates with the participants preparing and presenting lesson plans to be used at their own schools. The workshop utilizes materials from HMC’s first course in engineering, Introduction to Engineering Design (known as “E4”) [1], and is taught in a studio mode [2]. This paper presents some background material on PEPS, including the program’s goals, the current structure of PEPS, a discussion of the assessment procedures used, and some reflections on future directions. Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright Ó 2002, American Society for Engineering Education Main Menu