Contrasting the use of tools for presentation and critique: Some cases from architectural education

This study investigates video recordings of design reviews in architectural education, focusing on how presentations and discussions of designs are contingent on the specific tools employed. In the analyzed recordings, three different setups are utilized: traditional posters, digital slide-show technologies, and combinations of the two. This range of different setups provides a set of contrasts that make visible the role of technologies in shaping the ways in which the reviews are conducted. The analysis is structured in three themes. First, we examine the sequential organization of digital presentations in relation to the spatial structure of poster-based presentations. Second, the different ways in which shared attention is established in digital, paper-based, and hybrid presentation practices are analyzed. Third, we address part-whole relations—how details in presented materials are put in relation to the overarching project or the presentation as a whole. Taken together, the analyses suggest that the detailed organization of the design review is transformed in subtle yet consequential ways through the introduction of digital slide-show technologies. These transformations are consequential not only locally, for the design review itself, but also for the instructive work that is accomplished through this practice. We conclude by discussing some implications for design, arguing that an increased awareness of how the practice is influenced by the different setups might be key for the proper adaptation of presentation technologies to particular purposes.     

A generalized Ufnarovski graph

An important tool for studying standard finitely presented algebras is the Ufnarovski graph. In this paper we extend the use of the Ufnarovski graph to automaton algebras, introducing the generalized Ufnarovski graph. As an application, we show how this construction can be used to test Noetherianity of automaton algebras.     

A non-Newtonian model based on limiting shear stress and slip planes—parametric studies

Parametric studies and corresponding results are presented using a rheological model based on the limiting shear stress and possible occurrence of slip planes. The model is applied to elastohydrodynamically lubricated line contacts with smooth surfaces and isothermal conditions. A few investigations are carried out where different parameters are varied. The first study investigates the influence on the film thickness distribution due to a variation of the maximum Hertzian pressure when the slide-to-roll ratio is constant. The second study investigates how far the non-Newtonian region propagates at low slide-to-roll ratios for a few different values of the Hertzian pressure. The results show that it is a remarkably small slide-to-roll ratio necessary to cause slip planes in a large part of the Hertzian contact zone. A third study regards the influence of the entrainment velocity on the film thickness generation at different slide-to-roll ratios. Finally some rheological parameters are varied. First, only the limiting shear stress at atmospheric pressure (τ₀) is varied, and second, a few different lubricants are studied, each with their own set of rheological parameters.     

Fast, accurate, and stable algorithm for the stress field around a zig-zag-shaped crack

A new scheme decreases memory usage and execution time for the evaluation of certain weighted Cauchy type singular integrals. The scheme is incorporated into an algorithm based on an integral equation of Fredholm second kind. The algorithm computes mode I and II stress intensity factors of cracks in infinite elastic domains. Problems with analytical solutions are solved with relative errors less than 10⁻¹⁵. Earlier investigators' results for kinked cracks with one to four corners are improved. Cracks with a large number of corners can also be studied. In an example the stress intensity factors of a crack with 100 corners are calculated with a relative error of less than 10⁻⁶.     

Creep and rupture behaviour in fibre bundles

The time dependent rupture of a fibre bundle under constant tensile load and with scatter in fibre stiffness and fibre strength is analysed using a general formulation of the creep law. The total rupture time is divided into an incubation time, with all fibres intact, and a failure propagation time where fibres fail progressively. Governing equations are given for both time intervals. It is shown that the failure propagation time interval is independent of the load if no spatial stress redistribution occurs and all fibres remain intact upon loading. For a bundle consisting of originally uniform fibres where a fraction is afflicted with a certain defect, the time intervals are calculated assuming Norton's non linear creep law.     

Low-temperature properties of styrene–butadiene–styrene polymer modified bitumens

Low-temperature properties of the modified bitumens containing styrene–butadiene–styrene (SBS) polymers were investigated using conventional methods, dynamic mechanical analysis (DMA) and bending beam rheometer (BBR). Effects of the characteristics of base bitumens and polymers and the proportion of the components on these properties were studied. The results indicated that SBS polymers improved low-temperature properties of bitumens. The degree of improvement generally increased with SBS content and were influenced slightly by SBS structure. The study also showed a statistically linear relationships between different low-temperature parameters.     

Modeling the flow behavior of a medium carbon microalloyed steel under hot working conditions

The constitutive equations for the flow behavior of a commercial 0.34 pct C-1.5 pct Mn-0.7 pct Si-0.083 pct V-0.018 pct Ti microalloyed steel were determined. For this purpose, uniaxial hot compression tests were carried out over a wide range of strain rates (10⁻⁴ to 10 s⁻¹) and temperatures (1123 to 1423 K). In combination with models developed in the literature, the experimental results permit the flow stress of the present steel to be predicted within ± 5 pct. It is shown that the classical constitutive equations must be modified to take the grain size into account, particularly when the latter is below 30 μm.     

Liquid and vapor phase silanes coating for the release of thin film MEMS

Stiction remains one of the biggest reliability problems in the fabrication of microelectromechanical systems (MEMS). This work investigates the techniques adapted to release thin-film devices (100 nm thick) and submicron gaps MEMS. First, a CMOS compatible wet release process was developed, using nonchlorinated silanes coating providing a high hydrophobicity (contact angle in the range of 110/spl deg/). Second, a vapor phase release process based on the same chemistry is shown to be adequate to release thin-film beams from a silicon-on-insulator wafer, where the wet process failed. This is to the authors' knowledge the first time that an in-use stiction-free release process has been demonstrated for such thin structures. The layers resist up to 300/spl deg/C without damage and X-ray reflectivity confirmed that homogeneous monolayers were obtained.