Eloisa Torres-Jimenez

An AHP application to select software for engineering education

Simulations help students to deal with complex real problems, therefore engineering instructors include these software packages in their teaching methodologies. To achieve a learning aim, different programs can be chosen. Which is the adequate choice? Based on educational criteria, we implement a well‐known selection method, the analytic hierarchy process (AHP), to find a satisfactory solution. An example portrays the selection tool performance in the thermal engineering field.

Analytic construction and analysis of spiral pocketing via linear morphing

In numerical control, pocketing is a widely extended machining operation with different industrial applications. Conventional strategies (directional and contour parallel) provide a uniform material removal rate, but they show discontinuities and undesirable stops. However, smooth spiral paths overcome discontinuities, although the removal rate is not constant, and their implementation is complex. In order to provide an in-between solution, our algorithm embeds an Archimedean spiral into a linear morphing definition of the pocket. The solution is smooth, simple, analytic, and leads to a B-spline curve. Different tests were performed to compare the proposed spiral to other conventional and spiral strategies. To study the influence of the tool-path geometry, we computed engagement angle and feed direction, and measured force and time. The results demonstrate that our spiral is a committed, analytic and easy to compute solution. We define spiral tool-paths via linear interpolation between closed curves.The algorithm is simple and provides an analytic solution in B-spline form.The tool path is smooth and maintains constant radial distances between laps.For non-convex pockets, the interpolation of its boundary and medial axis provides the spiral.Cutter engagement, feed direction, time and forces help to analyse the spiral.

Spreadsheet for teaching reciprocating engine cycles

In an advanced heat engine course, we propose using a spreadsheet application to assist in the study of a reciprocating engine model, where the fluid composition changes and the parameters depend on the temperature. This application performs the fluid cycle analysis of different engines and also provides experience to students about computational procedures in heat engines.

Mobile learning: Using QR codes to develop teaching material

In recent years, the presence of mobile devices is increasing significantly in society as well as its potential applications. However, in the field of education, the possibilities offered by augmented reality are still untapped. This paper aims a first approach to the integration of QR codes in teaching engineering subjects. Experience shows the restructuring of the subject “Electronic Instrumentation”, objectives and results in the application of mobile learning through QR codes implemented.

Using wikis for collaborative work assessment in an electronic instrumentation course

This work shows how wikis provide an adequate frame for collaborative work, and help to evaluate it. Using the wiki tools available in the educational web platform Ilias, the students of an Electronic Instrumentation course work in teams to accomplish different tasks. After the activity due date, professors use wiki tools such as contributions index, submission history, and changes list, to assess, in an objective way, group and individual progress. The experience demonstrates to motivate student participation.

Advancing front circle packing to approximate conformal strips

A circle packing is a set of tangent and disjoint discs. Maps between circle packings with the same tangency are discrete analogues of conformal mappings, which have application for example in mechanical, fluid, and thermal engineering. We describe an advancing front algorithm to compute the circle packing of a strip around a closed planar curve. Conformal mappings preserve local angles and shapes; our algorithm uses these properties to obtain via the fast Fourier transform the centers and radii for the circle packing of successive trigonometric Lagrange curves in a strip. To check the algorithm, different results are compared with well-known conformal mappings. Real time deformations of circle packings are possible by changing the shape of the initial closed curve.