Edward E. Anderson

Heat Transfer in Semitransparent Solids

Publisher Summary The chapter presents an overview of the background information needed to formulate and analyze heat transfer in semitransparent materials systematically and then reviews the literature in some specific problem areas. Primary emphasis is placed on semitransparent solids, although the principles presented are general and apply to any phase. The chapter also discusses the wide variety of applications and involves nature of heat transfer phenomena in semitransparent condensed phases. The radiation characteristics of semitransparent materials are not only dependent on surface but also volume phenomenon since some of the emitted radiation originates at considerable depths. In short, the radiation characteristics depend on the spectral absorption coefficient and index of refraction, thickness, boundary conditions, and temperature distribution. The transient heating of semitransparent materials under idealized conditions in which the emission of radiation from the material is neglected is also discussed. This implies that the body is cold and the rate of emission of radiation per unit volume is negligible compared to absorption. This simplification limits the applicability of analysis and results to those early stages of heating during which temperatures have not raised high enough to render the assumption invalid. The chapter also presents an analysis to show the influence of physical parameters on the temperature field in a semitransparent solid irradiated from a high temperature source such as the sun. The results intend to aid the designer of solar collectors in selecting the optimum material by indicating physical parameters, which determine maximum efficiency of solar energy conversion in different semitransparent solids.

Force analysis of a laser beam incident on a fluid jet.

For the purposes of investigating the use of a small perturbation to control the break up of a fluid jet, an analysis was performed which describes the force incident on a fluid jet due to radiation pressure. Two cases were addressed; one which considers only reflection, as occurs when the fluid is opaque, and one in which reflection and a subsequent transmission are considered, as when the fluid is semitransparent. The results show that in both cases, for a well focused laser beam, a finite force can be obtained which is not critically influenced by the location of the laser beam with respect to the fluid jet.

Panel session - improving learning and retention in introductory statics

Statics is the first engineering class mechanics-based majors encounter. It tends to operate as a “weeder” course, due to most students’ difficulties in learning the engineering approach to problem solving, which is characterized by model-based reasoning. Difficulty in model-building can cause a lack of confidence and a diminished sense of self-efficacy that is particularly problematic when amplified by gender and under represented minority (URM) issues. Many valuable attempts have been made in the past at developing new tools to help students learn modeling, and develop engineering intuition. The goal of this panel is a two-pronged discussion: on the one end, present and discuss the most pertinent and intractable challenges associated with Statics learning that students encounter; on the other, present and discuss various interventions, technological or otherwise, that the panelists have attempted and/or developed to remedy the situation. Ideally the panel outcome will be to define pathways for developing and disseminating cognitively-based interventions that better supports learning and retention of all engineering students.

M-MODEL: Design and Implementation of an On-line Homework System for Engineering Mechanics

Students solve problems by developing mental models of the problem. Although these models are many and diverse, a common one used in engineering mechanics education consists of identifying the known and unknown variables, construction of a graphical problem representation, and developing a mathematical model derived from the preceding steps. This is also the case for courses in physics, mechanics, science and electrical circuits. M-MODEL is a computer-based implementation of this approach to problem-solving. It utilizes the visual graphic, variables identification and listing, and mathematical equation mental models as a construct for students to developing STEM problem solving skills. This paper describes how students use M-MODEL to solve problems and its coaching tools. This paper discusses the design objectives, intelligent tutor, and features of M-MODEL as applied to an engineering mechanics course. It also discusses how M-MODEL may be used to encourage students to develop mental model approaches to problem solving. An assessment of M-MODEL is also presented.

An Interactive Web-Based Approach to Perform Full-Scale Tensile Testing Experiments

An interactive web-based software on ‘Tensile Testing of Materials’ is developed to help undergraduate students learn more effectively about the objectives, procedure, and methods used in the experiment. The main objective was to better prepare the students in performing their tasks during the physical experiment. The intention of this project is to reap the benefits of both web based training as well as performing the experiments in a practical and interactive sense. Access to the software is given to the students before performing the actual experiment. The software is evaluated to assess its effectiveness. Our initial results verify that the virtual lab could be an effective tool in preparation of the students for the actual experimental tasks in a laboratory environment. In the following paper, the design of the software, important elements of the virtual lab and the evaluation results will be presented.Copyright