Force modelling of the crankshaft pin grinding process.

A force model was developed for crankshaft pin grinding to predict the forces generated during grinding. The force model developed builds on the authors’ previously developed model, which predicted the out-of-roundness in crankshaft pin grinding. The model includes key grinding variables, such as the work removal parameter (WRP), system sti€ ness and Young’s modulus to determine the end forces produced. The model also includes the important geometrical relationships that are unique to this type of grinding. The model was veriŽ ed using an experiential set-up involving sophisticated strain gauge force measurements on a commercial Landis CP grinding machine, with close correlation between the results and the model.

Biomechanical studies: science (f)or common sense?

 Introduction: It is our impression that many biomechanical studies invest substantial resources studying the obvious: that more and larger metal is stronger. The purpose of this study is to evaluate if a subset of biomechanical studies comparing fixation constructs just document common sense. Methods: Using a web-based survey, 274 orthopaedic surgeons and 81 medical students predicted the results of 11 biomechanical studies comparing fracture fixation constructs (selected based on the authors' sense that the answer was obvious prior to performing the study). Sensitivity, specificity, and accuracy were calculated according to standard formulas. The agreement among the observers was calculated by using a multirater kappa, described by Siegel and Castellan. Results: The accuracy of predicting outcomes was 80% or greater for 10 of 11 studies. Accuracy was not influenced by level of experience (i.e., time in practice and medical students vs. surgeons). There were substantial differences in accuracy between observers from different regions. The overall categorical rating of inter-observer reliability according to Landis and Koch was moderate (k = 0.55; standard error (SE) = 0.01). Conclusion: The results of a subset of biomechanical studies comparing fracture fixation constructs can be predicted prior to doing the study. As these studies are time and resource intensive, one criterion for proceeding with a biomechanical study should be that the answer is not simply a matter of common sense. © 2014 Elsevier Ltd. All rights reserved.

Negotiating the hidden curriculum: power and affect in negotiated classrooms

Garth Boomer's ideas in Negotiating the Curriculum (1992a) resonate with discussions of shifting teacher and student roles and relationships in the 'student voice' movement. Boomer (1988) critiqued his earlier conception of power in Negotiating the Curriculum, asserting that he would 'now like to write a book on Negotiating the Hidden Curriculum', in which he would conduct an ethnographic 'micro-analysis' of the 'moment-by-moment dance' between teachers and students and the fluctuations in the 'flows and ebbs of affect and primal resistance in teachers and taught' (p. 171). This article takes up this provocation, considering a 2013 meeting of a cross-age student voice group where students, teachers and researchers collectively discussed the meanings and manifestations of the hidden curriculum through exploring Pink Floyd's Another Brick in the Wall (Waters, 1979), other film representations of school, and their own school. Four students and I analysed a transcript from this meeting, considering the dynamics of power and affect in negotiated classrooms.

Conserving long unburnt vegetation is important for bird species, guilds and diversity

Landscape-level wildfires have a major role in structuring faunal assemblages, particularly in fire-prone landscapes. These effects are mediated by changes to vegetation structure and composition that directly influence the availability of shelter, feeding and breeding resources. We investigated the response of a semi-arid shrubland bird community in Western Australia to the prevailing fire regime by examining the abundance, diversity and guild structure in relation to time since fire. We also examined vegetation structural attributes in relation to time since fire. We surveyed 32 sites ranging in age from 12 to 84 years since last fire. A total of 845 birds from 40 species were recorded. Vegetation structure varied with fire history with old and very old sites characterised by less bare ground, more leaf litter cover and greater canopy cover. Bird community composition varied with time since fire, driven by increased bird species richness and abundance of insectivores, granivores/frugivores, golden whistlers, grey shrike-thrush and red-capped robins with time since fire. Frequent, intense landscape-scale fires transform the landscape into homogeneous young shrublands, which may render vegetation unsuitable for several species and guilds.