Current Understanding of Structure–Processing–Property Relationships in BaTiO3–Bi(M)O3 Dielectrics

As part of a continued push for high permittivity dielectrics suitable for use at elevated operating temperatures and/or large electric fields, modifications of BaTiO₃ with Bi(M)O₃, where M represents a net‐trivalent B‐site occupied by one or more species, have received a great deal of recent attention. Materials in this composition family exhibit weakly coupled relaxor behavior that is not only remarkably stable at high temperatures and under large electric fields, but is also quite similar across various identities of M. Moderate levels of Bi content (as much as 50 mol%) appear to be crucial to the stability of the dielectric response. In addition, the presence of significant Bi reduces the processing temperatures required for densification and increases the required oxygen content in processing atmospheres relative to traditional X7R‐type BaTiO₃‐based dielectrics. Although detailed understanding of the structure–processing–property relationships in this class of materials is still in its infancy, this article reviews the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO₃‐Bi(M)O₃ dielectrics as well as the processing challenges and opportunities associated with these materials.     

Enhancement of Spatial Sound Quality: A New Reverberation-Extraction Audio Upmixer

A system for the extraction of uncorrelated reverberation from two-channel (stereo) audio signals is proposed and evaluated. Applications for the new system vary from surround-sound multichannel loudspeaker upmixers for home-theater or automotive audio systems, to headphone-based auralization for enhancing the spatial sound quality of a listening experience. The new system uses the normalized-least-mean-square (NLMS) algorithm to equalize the two input signals with respect to both spectral magnitude and phase before differencing to remove correlated components. A theoretical model of the system based on a stochastic room impulse response model was validated by empirical measurements made in a reverberant hall with a microphone pair, and from a formal subjective evaluation the system is shown to be an effective approach to extracting reverberation from audio recordings.     

Technology adoption in the BIM implementation for lean architectural practice

Justification for researchThe construction companies are facing barriers and challenges in BIM adoption as there is no clear guidance or best practice studies from which they can learn and build up their capacity for BIM use in order to increase productivity, efficiency, quality, and to attain competitive advantages in the global market and to achieve the targets in environmental sustainability.

Purpose

This paper aims to explain a comprehensive and systemic evaluation and assessment of the relevant BIM technologies as part of the BIM adoption and implementation to demonstrate how efficiency gains have been achieved towards a lean architectural practice.Design/methodology/approachThe research is undertaken through a KTP (Knowledge Transfer Partnership) project between the University of Salford and the John McCall Architects based in Liverpool, which is an SME (Small Medium Enterprise). The overall aim of KTP is to develop a lean design practice through the BIM adoption and implementation. The overall BIM implementation approach uses a socio-technical view in which it does not only consider the implementation of technology but also considers the socio-cultural environment that provides the context for its implementation. The technology adoption methodology within the BIM implementation approach is the action research oriented qualitative and quantitative research for discovery, comparison, and experimentation as the KTP project with JMA provides an environment for “learning by doing”.

Findings

Research has proved that BIM technology adoption should be undertaken with a bottom-up approach rather than top-down approach for successful change management and dealing with the resistance to change. As a result of the BIM technology adoption, efficiency gains are achieved through the piloting projects and the design process is improved through the elimination of wastes and value generation.

Originality/value

Successful BIM adoption needs an implementation strategy. However, at operational level, it is imperative that professional guidelines are required as part of the implementation strategy. This paper introduces a systematic approach for BIM technology adoption based on a case study implementation and it demonstrates a guideline at the operational level for other architectural companies of architectural practices.     

Weibull component reliability-prediction in the presence of maskeddata

Analysts are often interested in obtaining component reliabilities by analyzing system-life data. This is generally done by making a series-system assumption and applying a competing-risks model. These estimates are useful because they reflect component reliabilities after assembly into an operational system under true operating conditions. The fact that most new systems under development contain a large proportion of old technology also supports the approach. In practice, however, this type of analysis is often confounded by the problem of masking (the exact cause of system failure is unknown). This paper derives a likelihood function for the masked-data case and presents an iterative procedure (IMLEP) for finding maximum likelihood estimates and confidence intervals of Weibull component life-distribution parameters. The approach is illustrated with a simple numerical example     

Analysis of nitrate and nitrite in foodstuffs: A critical review

A general review is presented of published methods for the determination of nitrate and nitrite levels in foodstuffs especially meat. Published methods show wide variations in techniques for extraction, clean-up (clearing) of extracts and final determinative steps and these are critically compared. The effect of interferences due to the presence of ascorbate, sulphite and phosphate together with the formation of a “meat blank” when nitrate is reduced to nitrite with spongy cadmium are discussed. Newer techniques based on the use of ion selective electrodes and automated techniques are outlined and the application of techniques such as amperometry, liquid chromatography, ion exchange and spectrophotometry are listed.