Narrative in design development

This paper describes the value of narrative used with ideation tools in aiding the rapid production of product concepts and designs for masters students of graphics, fine art, product and industrial design. The ideation tools used alongside narrative included elements of divergent and convergent thinking in combination with reverse engineering and functional analysis, and practical prototyping using a range of readily adapted artefacts. Narrative was introduced and used by the students in order to ensure the development of a context and purpose for the product, artefact or system developed or proposed and to stimulate original product concepts, ideas and thinking. The concept of narrative is familiar in design. Here however the concept was reinforced using structures associated with fictional narrative. Reverse engineering exploring the deconstruction and identification of function for each component in a product was used to aid students ensure practicality in their idea implementation. This paper describes positive experiences resulting from this activity, with a particular focus on the value of narrative in developing robust concepts. The use of physical prototyping provided tangible and instant feedback for divergent and convergent phases of idea development

Influence of impeller shroud forces on turbopump rotor dynamics

The shrouded-impeller leakage path forces calculated by Childs (1987) have been analyzed to answer two questions. First, because of certain characteristics of the results of Childs, the forces could not be modeled with traditional approaches. Therefore, an approach has been devised to include the forces in conventional rotordynamic analyses. The forces were approximated by traditional stiffness, damping and inertia coefficients with the addition of whirl-frequency-dependent direct and cross-coupled stiffness terms. The forces were found to be well-modeled with this approach. Finally, the effect these forces had on a simple rotor-bearing system was analyzed, and, therefore, they, in addition to seal forces, were applied to a Jeffcott rotor. The traditional methods of dynamic system analysis were modified to incorporate the impeller forces and yielded results for the eigenproblem, frequency response, critical speed, transient response and an iterative technique for finding the frequency of free vibration as well as system stability. All results lead to the conclusion that the forces have little influence on natural frequency but can have appreciable effects on system stability. Specifically, at higher values of fluid swirl at the leakage path entrance, relative stability is reduced. The only unexpected response characteristics that occurred are attributed to the nonlinearity of the model

Numerical modeling tools for chemical vapor deposition

Development of general numerical simulation tools for chemical vapor deposition (CVD) was the objective of this study. Physical models of important CVD phenomena were developed and implemented into the commercial computational fluid dynamics software FLUENT. The resulting software can address general geometries as well as the most important phenomena occurring with CVD reactors: fluid flow patterns, temperature and chemical species distribution, gas phase and surface deposition. The physical models are documented which are available and examples are provided of CVD simulation capabilities

Scaffolds and Generalized Integral Galois Module Structure

Let $L/K$ be a finite, totally ramified $p$-extension of complete local fields with residue fields of characteristic $p > 0$, and let $A$ be a $K$-algebra acting on $L$. We define the concept of an $A$-scaffold on $L$, thereby extending and refining the notion of a Galois scaffold considered in several previous papers, where $L/K$ was Galois and $A=K[G]$ for $G=\mathrm{Gal}(L/K)$. When a suitable $A$-scaffold exists, we show how to answer questions generalizing those of classical integral Galois module theory. We give a necessary and sufficient condition, involving only numerical parameters, for a given fractional ideal to be free over its associated order in $A$. We also show how to determine the number of generators required when it is not free, along with the embedding dimension of the associated order. In the Galois case, the numerical parameters are the ramification breaks associated with $L/K$. We apply these results to biquadratic Galois extensions in characteristic 2, and to totally and weakly ramified Galois $p$-extensions in characteristic $p$. We also apply our results to the non-classical situation where $L/K$ is a finite primitive purely inseparable extension of arbitrary exponent that is acted on, via a higher derivation (but in many different ways), by the divided power $K$-Hopf algebra.Comment: Further minor corrections and improvements to exposition. Reference [BE] updated. To appear in Ann. Inst. Fourier, Grenobl

Engineering freakout

Design and engineering have worldwide impact. The products and systems generated affect every level of our lives. In a competitive world where the prosperity of local industry waxes, wanes and emerges in new forms, temporal strategies and policies for survival and gain inevitably emerge. It is in this context that engineers and designers operate their exciting trades, with consideration of multiple functional attributes in any given application. This may involve attention to technical, aesthetic, economic, social and latent function and their often complicated interrelationships, with one attribute affecting the performance of others in a significant manner. The value of each attribute needs to be maintained at the design stage in order to deliver worldwide competitive products, systems and services. It is in the conceptual, detailed design, fire-fighting and application phases that engineering analysis shows its potential, time and time again, to deliver order-of-magnitude as well as validated estimates for quantities. The tools of engineering provide essential input and infl uence for the design process. These tools can be operated with diligence and exacting analysis, as well as in the fast-paced conceptual stages of any project, in order to explore the what if and to provide a physical basis for an idea, as well as the impetus to give that idea the justification for the resources it requires for elaboration. © Manchester University Press

Wave Profile for Current Bearing Antiforce Waves

For fluid dynamical analysis of breakdown waves, we employ a one-dimensional, three-component (electrons, ions and neutral particles) fluid model to describe a steady-state, ionizing wave propagating counter to strong electric fields. The electron gas temperature and therefore the electron fluid pressure is assumed to be large enough to sustain the wave motion down the discharge tube. Such waves are referred to as antiforce waves. The complete set of equations describing such waves consists of the equations of conservation of mass, momentum and energy coupled with Poisson’s equation. Inclusion of current behind the wave front alters the set of electron fluid dynamical equations and also the boundary condition on electron temperature. For a range of experimentally observed current values, using the modified boundary condition on electron temperature, we have been able to integrate our modified set of electron fluid dynamical equations through the Debye layer. Our solutions meet the expected boundary conditions at the trailing edge of the wave. We present the wave profile for electric field, electron velocity, electron number density and electron temperature within the Debye layer of the wave

Prevalence of Helicobacter pylori in patients with gastro-oesophageal reflux disease : systematic review.

Objectives: To ascertain the prevalence of Helicobacter pylori in patients with gastro-oesophageal reflux disease and its association with the disease. Design: Systematic review of studies reporting the prevalence of H pylori in patients with and without gastro-oesophageal reflux disease. Data sources: Four electronic databases, searched to November 2001, experts, pharmaceutical companies, and journals. Main outcome measure: Odds ratio for prevalence of H pylori in patients with gastro-oesophageal reflux disease. Results: 20 studies were included. The pooled estimate of the odds ratio for prevalence of H pylori was 0.60 (95% confidence interval 0.47 to 0.78), indicating a lower prevalence in patients with gastro-oesophageal reflux disease. Substantial heterogeneity was observed between studies. Location seemed to be an important factor, with a much lower prevalence of H pylori in patients with gastro-oesophageal reflux disease in studies from the Far East, despite a higher overall prevalence of infection than western Europe and North America. Year of study was not a source of heterogeneity. Conclusion: The prevalence of H pylori infection was significantly lower in patients with than without gastro-oesophageal reflux, with geographical location being a strong contributor to the heterogeneity between studies. Patients from the Far East with reflux disease had a lower prevalence of H pylori infection than patients from western Europe and North America, despite a higher prevalence in the general population