Darrell Guillaume

The effect of time‐on‐task on student grades and grade expectations

The effects of students’ attitudes on time devoted to a course (i.e. time‐on‐task), and the subsequent effects of this time‐on‐task on their performance in the course and their overall grade point average (GPA) were studied. Over a three‐year period, engineering students (N = 231) were surveyed in weeks one, three, seven (after midterms) and 10 (before finals) of a 10‐week quarter in six sophomore and junior engineering classes (eight different sections). Results of this study show that most students are optimistic about their future performance in a new course, regardless of their previous overall GPA. All students appear to devote a relatively high and equal amount of time‐on‐task during the first week of the term. The students who earned grades between ‘B+’ and ‘A’ appear to optimise this time by the third week. Students who earned a final grade of ‘B’ study similar to ‘A’ students before midterms but significantly increase their efforts after midterms while the ‘C’ students decrease their time devoted to the course. This study finds that ‘A’ students know they will earn an ‘A’ as long as they do the work. In contrast, ‘C’ students are resigned to the fact that they will earn a ‘C’ and, thus, devote far less time to a course. The ‘B’ students want better grades and will devote the most effort towards achieving these grades.

The effect of context on student engagement in engineering

The self-belief, motivation, tendency to procrastinate and learning styles of engineering students are discussed. It is proposed that engineering has developed an idiom and a learning approach that favours the dominant client, i.e. men, while simultaneously undermining the self-efficacy and motivation of women. Thematic coherence and teaching within a context that is familiar to students have been shown previously to be effective approaches for engaging students and are extended here to utilise the common experiences of all students to initiate the learning cycle. These approaches are combined with a template for teaching that uses the 5Es (Engage, Explore, Explain, Elaborate and Evaluate) in order to render the fundamentals of engineering more accessible to all students. This methodology can be introduced by individual instructors, who will be rewarded by students who are more engaged, more motivated and more likely to give a higher rating to the instructor and the course.

Demonstrating the achievement of lower temperatures with two-stage vortex tubes

Vortex tubes separate single inlet streams of compressed air into two discharge streams. One stream exits at a lower temperature than the inlet stream, and the other exits at a higher temperature. The difference between the lower outlet temperature and the inlet temperature is ΔT. This study demonstrates that with equal inlet temperatures, a two-stage vortex tube (i.e., two vortex tubes operating simultaneously in series) can produce a greater ΔT than the ΔT produced by either one of the vortex tubes operating independently. Specifically, results demonstrate that two single-stage tubes that have ΔT values, which are, respectively, −17.37 and −16.17 °C, can be combined into a two-staged vortex tube that has a ΔT of −19.33 °C. Thus, the cooling capability of a vortex tube can be increased by staging.

Improving the efficiency of a jet pump using an elliptical nozzle

This note presents a unique means of increasing the efficiency of a jet pump. Much research has been devoted to the study of elliptical nozzles on jets and their ability to increase the amount of fluid entrainment over round jets with equal perimeters. Since the efficiency of a jet pump is directly related to the ability of the primary jet to entrain fluid, a jet pump is an obvious potential application of these elliptical nozzles. In this study, the efficiency of a jet pump is measured using a jet with a round cross section and a jet with an elliptical cross section that has a 3:1 aspect ratio. At high flowrates, the jet pump using the elliptical jet is shown to have an efficiency that is approximately a factor of 6 greater than the pump using the round jet.

Deconstructing Engineering Education Programmes: The DEEP Project to reform the mechanical engineering curriculum

The goal of the Deconstructing Engineering Education Programmes project is to revise the mechanical engineering undergraduate curriculum to make the discipline more able to attract and retain a diverse community of students. The project seeks to reduce and reorder the prerequisite structure linking courses to offer greater flexibility for students. This paper describes the methods used to study the prerequisites and the resulting proposed curriculum revision. The process involved dissecting each course into topics at roughly the level of a line in a syllabus, editing the list of topics, associating prerequisites and successors to each topic and then using a genetic algorithm to produce clusters of topics. The new curriculum, which consists of 12 clusters, each of which could be a full year course, is quite different from the traditional curriculum.

Changes in student effort and grade expectation in the course of a term

Students were surveyed and asked to self-evaluate their performance and time-on-task in six engineering courses (eight sections). Surveys were conducted four times over the course of a 10-week quarter. Students with the highest grade point averages (GPAs) (2.88 mean; 4.00 mode) indicated ‘no change’ while students with lower GPAs (2.67 mean; 1.83 mode) indicated a ‘negative change’ in grade expectations by the end of the quarter, indicating that better performing students are better self-evaluators. Students reduced time-on-task 2–4 hours/week, especially early in the quarter. Students who changed their time-on-task during each survey had a GPA mode of 4.00, indicating that ‘master’ students readily adapt to course demands. This study shows that most students over-predict their grades and their level of commitment to a course and lose confidence in their abilities as the term progresses. It is suggested that instructors obtain student grade predictions and use them to provide timely and appropriate feedback.

Control of a simulated wing structure with multiple segmented control surfaces

The main objective of this paper is to demonstrate that a wing with segmented control surfaces can redistribute its load, inboard or outboard, in order to perform active shape control while still maintaining level flight. Methods will be presented for controlling the plunge deflections of an aircraft wing structure. One possible solution to improving the flight envelope is a wing design with multiple segmented control surfaces all along its span. This will give an aircraft far more control over its lift distribution in comparison to a typical wing. In order to construct a wing with segmented trailing edges, it must first be shown that deflections under lift loads can be controlled. This paper introduces the research performed by the Structures, Propulsion, and Controls Engineering (SPACE) Center using a Fiber-Optic Strain-Sensing (FOSS) system that is currently implemented on the Odyssey UAV. The research will use a set of strain-based Displacement Transfer Functions (DTF) and the FOSS System both of which were developed at the NASA Dryden Flight Research Center (DFRC). Aerodynamic loads are obtained through the use of the software Athena Vortex Lattice (AVL). In addition, structural modeling is carried out with the use of finite element software. The results indicate that the shape of a wing structure can be controlled through the manipulation of segmented control surfaces to re-distribute lifting loads.

Design and development of an automated flow injection instrument for the determination of arsenic species in natural waters

The design and development of an automated flow injection instrument for the determination of arsenite [As(III)] and arsenate [As(V)] in natural waters is described. The instrument incorporates solenoid activated self-priming micropumps and electronic switching valves for controlling the fluidics of the system and a miniature charge-coupled device spectrometer operating in a graphical programming environment. The limits of detection were found to be 0.79 and 0.98 microM for As(III) and As(V), respectively, with linear range of 1-50 microM. Spiked ultrapure water samples were analyzed and recoveries were found to be 97%-101% for As(III) and 95%-99% for As(V), respectively. Future directions in terms of automation, optimization, and field deployment are discussed.

A comparison of peak frequency-time plots produced with Hilbert and wavelet transforms

Practical techniques for producing both Hilbert and wavelet transform representations of peak frequency are given. Peak frequency-time plots of simple model signals are produced using both transforms and are presented and compared. This study shows that the peak frequency-time plots produced using the wavelet transform are superior to those produced using the Hilbert transform since the wavelet representation does not show large false frequency indications when the model time series undergoes a large abrupt frequency change. Further, when multiple dominant frequencies are present in the model time series, the wavelet based peak frequency-time plot more clearly identifies the higher of the dominant frequencies while the Hilbert based peak frequency-time plot is affected by the lower frequency and leads to less clear results.

Cooperative Semi-autonomous Robotic Network for Search and Rescue Operations

The results presented in this paper prove the viability of developing a robotic network for search and rescue operations. With the capability of peer-to-peer communication, such robots form an ad-hoc network called Cooperative Mobile Network CMN. All robots in the CMN are semi-autonomous in that each operates in three modes: 1 fully controlled by a human commander; 2 controlled by a human commander for critical operations only; and 3 fully relying on its own intelligence to make decisions for cooperative operations. Due to the constraints of weight and processing power, diverse CMN operations utilize multiple robots with complementing functionalities. This work was performed at the Structures Propulsion And Control Engineering SPACE NASA sponsored University Research Center URC of excellence at the California State University, Los Angeles.