Student perceptions of model-based estimating

The use of building information modeling (BIM) is well established in architecture, engineering and construction. However, previous studies note a lack of BIM expertise in academia, leading to slow adoption and limited knowledge on which to base BIM-related content. To improve course development, it is important to understand students’ perceptions of BIM-related subject matter. This study exposed estimating students (n = 214) to a model-based quantity takeoff (QTO) tutorial using Revit. Students’ perceptions of a Revit-based BIM’s usefulness for easily providing reliable and accurate material quantities were measured using a pre-test, tutorial and post-test design. Results revealed significant differences in students’ mean levels of agreement that an accurate QTO is completed for an estimator with the click of a button when a design team generated BIM model is available. Results also revealed significant differences in students’ level of agreement that a Revit-based BIM makes performing QTO by hand obsolete. This study provides educators’ insight into students’ perceptions of BIM use in QTO. Understanding student perceptions is paramount for construction management educators when designing a course and attempting to convey the value of foundational estimating skills while acknowledging the existence of more technologically advance estimating methods. Limitations and opportunities for further research are discussed.     

Atomistic Origin of the Enhanced Crystallization Speed and n‐Type Conductivity in Bi‐doped Ge‐Sb‐Te Phase‐Change Materials

Phase‐change alloys are the functional materials at the heart of an emerging digital‐storage technology. The GeTe‐Sb₂Te₃ pseudo‐binary systems, in particular the composition Ge₂Sb₂Te₅ (GST), are one of a handful of materials which meet the unique requirements of a stable amorphous phase, rapid amorphous‐to‐crystalline phase transition, and significant contrasts in optical and electrical properties between material states. The properties of GST can be optimized by doping with p‐block elements, of which Bi has interesting effects on the crystallization kinetics and electrical properties. A comprehensive simulational study of Bi‐doped GST is carried out, looking at trends in behavior and properties as a function of dopant concentration. The results reveal how Bi integrates into the host matrix, and provide insight into its enhancement of the crystallization speed. A straightforward explanation is proposed for the reversal of the charge‐carrier sign beyond a critical doping threshold. The effect of Bi on the optical properties of GST is also investigated. The microscopic insight from this study may assist in the future selection of dopants to optimize the phase‐change properties of GST, and also of other PCMs, and the general methods employed in this work should be applicable to the study of related materials, for example, doped chalcogenide glasses.     

Evolution of supramolecular healable composites: a minireview

Efforts to further extend the range of applications of polymer based materials have resulted in the recent production of healable polymers that can regain their strength after damage. Within this field of healable materials, supramolecular polymers have been subject to extensive investigation. By virtue of their reversible non‐covalent interactions, cracks and fractures in such polymers can be readily and repeatedly healed in order to regain key physical properties. However, many supramolecular polymers are relatively weak and elastomeric in nature, which renders them unsuitable for high strength structural applications. To overcome these deficiencies, preliminary studies have shown that it is possible to reinforce supramolecular polymers with microscale and nanoscale fillers to afford composites that are not only stronger and stiffer compared with the polymers alone but also retain their healing abilities. In this minireview we discuss the evolution of these supramolecular composites and their advantages over more conventional, covalent polymeric materials. © 2014 Society of Chemical Industry     

Comparing GC–MS,HPLC and H NMR analysis of beef longissimus dorsi tissue extracts to determine the effect of suspension technique and ageing

Beef longissimus dorsi muscle samples matured over a 21 day period were analysed using three different analytical techniques; ¹H NMR, GC–MS and HPLC. The data from the three experimental techniques were correlated with each other to determine if the results were statistically similar to each other. From our analysis we determined that the metabolites measured using ¹H NMR were statistically similar to the compounds quantified using the chromatography techniques (p < 0.001). In addition, using PCA, we were able to show that different metabolites, measured using the various analytical techniques produced very similar scores and loadings plots for all the analysis and extraction techniques undertaken across the 21 day time domain. Using a combination of these three different techniques provides a unique and holistic insight into the biochemistry behind the conversion of muscle to meat which would not be possible using any single technique alone.     

Low-level temporal coding impairments in psychosis: Preliminary findings and recommendations for further studies.

The authors investigated whether difficulties with temporal event coding, previously reported in patients with schizophrenia, are already present during first-episode psychosis (FEP). In this experiment, the subjective judgments of the simultaneity of visually presented stimuli were compared between 11 healthy controls, 9 patients with chronic schizophrenia (CSZ), and a sample of 11 FEP patients. Participants were asked to indicate whether 2 vertical bars appeared at the same time or at different times on a computer monitor. CSZ patients' thresholds were elevated, and the FEP sample showed higher thresholds relative to controls. Although preliminary, these findings indicate a generalized disturbance in event-structure coding at early stages of psychosis and question the specificity of its disturbance. Considering the proposed relationship between event-structure coding and the experience of time in general, this study recommends that future studies refocus on psychosis in general, rather than on schizophrenia as a particular case of abnormal temporal processing. In addition, it is suggested that the relevant psychopathology will be best determined by means of a comprehensive analysis of low-level temporal coding performance in different types of psychosis. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects and perceived consequences of testing accommodations on math and science performance assessments.

The present study examined the effect accommodations have on test results of students with and without disabilities and documented experts’ judgments about the appropriateness of testing accommodations. Test score data were collected from 218 fourth-grade students with and without disabilities on mathematics and science performance tasks and from eight testing experts who evaluated the fairness and validity of a sample of testing accommodations used with these students. Results indicated that, for most students with disabilities and some students without disabilities, packages of testing accommodations had a moderate to large effect on performance task scores. Expert reviewers rated most accommodations for a student with disabilities as being both valid and fair, and they gave accommodations listed on a student’s individualized education program (IEP) significantly higher validity and fairness ratings than accommodations that were not listed on the student’s IEP. Interpretations of these data are provided and implications for practice and future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Variety of Scale

It is a truism that the essential qualities of a work of architecture cannot, since architecture is a visual art, be fully conveyed in words. No one would seriously maintain that this absolves those whose business it is to write or talk about architecture from the obligation to use words with some regard for exactness. Yet all too often we behave as if it did; certain words are bandied about as if all were agreed as to what they meant at any time, whereas in fact they may mean different things at different times, and even different things to different people at one time. Cecil Elliott here takes up the case of one such word, a small but much-abused one, isolating four distinct phenomena which it can denote in an architectural context and pursuing his inquiry beyond the realm of semantics to consider their practical implications for the designer.