Louis L. Bucciarelli

An ethnographic perspective on engineering design

Abstract This paper reports two studies of the design process within engineering firms. The studies were based on participant-observation techniques: in each case the firm was approached in the way an ethnographer might approach a foreign culture. The paper presents and discusses observations of typical activities that occur in the design process. In particular, design is observed as a social process. Three types of discourse are identified: constraining, naming and deciding.

Between thought and object in engineering design

Abstract If one accepts that engineering design is the business of a collective or team and that different participants, with different competencies, responsibilities and interest ‘see’ the object of design differently, then the question arises: how do they harmonize their claims and proposals throughout the course of design? For that matter, how does any one participant, working alone, exercising his or her expertise, transform ideas of function into plans which ultimately fix the form and structure of the product? We explore the possibility of extending the scope of language to include artifacts of process – sketches, bits and pieces of hardware – to see how they might serve to bridge thought and object.

Estimating loss-of-power probabilities of stand-alone photovoltaic solar energy systems

Abstract This paper describes an approximate approach to evaluating the performance, including the probability of loss-of-power (or loss-of-load, as some would have it) of stand-alone photovoltaic solar energy systems. The method treats the energy capture, storage and disbursement process as a random walk in the storage domain. To apply the technique, one must know the variance, as well as the mean, of the probability density of the daily solar insolation impinging onto the photovoltaic array. Analytical expressions are obtained for the probability of depleting the systems storage, as well as how much auxiliary energy, on the average, would be required to cover the load in that event.

Ethics and Engineering Education

In the US, Accreditation Board for Engineering and Technology (ABET) recommends the study of ethics so that students acquire ‘an understanding of professional and ethical responsibility’. For the most part, teaching of the subject relies upon the use of scenarios – both hypothetical and ‘real’– and open discussion framed by the codes. These scenarios and this framing are seriously deficient – lacking in their attention to the complexities of context, almost solely focused on individual agency, while reflecting too narrow and simplistic a view of the responsibilities of the practicing engineer. A critique of several exemplary scenarios, and consideration of the demands placed upon todays professional, prompt reflection on the need for, not just a more expansive reading of the codes of ethics re what it might mean to be ‘responsible’, but a substantial reform of undergraduate engineering education across the board.

Power loss in photovoltaic arrays due to mismatch in cell characteristics

Abstract Variations in the current-voltage characteristics of photovoltaic cells can lead to significant power loss “due to mismatch” when the cells are connected together in a network. This study explores how this mismatch loss depends on variations in max-power current and max-power voltage from cell to cell. An analysis of a series string is first performed. Losses in a parallel string are also determined. Estimates of mismatch losses in more complex arrays are then obtained. In addition to generally excellent comparison with several numerical studies, results show that, for a series string, there exists a critical magnitude of deviation in cell max-power current beyond which the power loss due to mismatch is sensitive to both the number of cells placed in series and the shape of the probability density function defining variations in max-power current. This critical level also depends on the cell fill-factor.

The effect of day-to-day correlation in solar radiation on the probability of loss-of-power in a stand-alone photovoltaic energy system

Abstract This paper extends a method previously developed by the author for evaluating the probability of loss-of-power of stand-alone photovoltaic solar energy systems. As before, the method treats the energy capture, storage and dispersement process as a random walk in the storage domain. Correlation in day-to-day levels of solar insolation is now taken into account in the derivation of an expression for the probability of depleting storage.

Designing and learning: a disjunction in contexts

Abstract Two ideologies about engineering, one claimed the habit of engineering design practitioners, the other that of engineering educators, are advanced. The two are incompatible. The disjunction is elaborated in terms of two distinct postulates and their consequences. A remedy for educators is recommended and the experiences of the author in attempting to change the context of learning to better accord with engineering practice are described.

Sophie Germain : an essay in the history of the theory of elasticity

1. Introduction.- 2. Sophie Germain.- 3. Respectfully Yours, Gauss.- 4. Setting the Prize.- 5. The One Entry.- 6. The Molecular Mentality.- 7. An Award with Reservations.- 8. Publication.- 9. Emergence of a Theory.- 10. Final Years.- Notes.

Design Knowing & Learning: A Socially Mediated Activity

Publisher Summary This chapter illustrates how the context of the engineering classroom might be transformed to better accord with the context of engineering practice through the introduction of open-ended, design-type exercises. While faculty can energize students with talk of creativity, and engage them in the act itself, the subject matter is considered “soft” and lacking in rigor when compared to courses in control theory, signals and systems, thermodynamics, computer science, or engineering mechanics. The analytic/synthetic distinction is alive and well in engineering education. This chapter explores this dichotomy, not in order to deny the differences between science based, theoretical knowledge, and design thinking and knowing, but rather to understand these two forms better and how they relate to the engineering practice. The way to better prepare students for engineering practice is to transform the context of the engineering classroom, not just in those courses explicitly labeled “design,” but across the board, starting with the engineering science courses at the sophomore level. Through the integration of open-ended, design-type exercises into the curriculum, a dramatic change in the atmosphere and context of the classroom can be achieved, and the fundamentals still be addressed with rigor.

Getting Context Back in Engineering Education

Discussions about reform in engineering education have mainly centered on issues of curriculum and didactics but these discussions rarely address fundamental questions about the nature and character of knowledge and learning. This neglect has led the discussions down the wrong track and failed to critique implicit and inadequate conceptions of knowledge and learning. Our discussion will draw upon John Dewey’s philosophy of human experience and inquiry as a resource that can remedy the neglect. This chapter thus focuses on learning and by example proposes ways that engineering knowledge and skills can be contextualized, taught – and learned.