Mechanistic studies of aromatic substitutions with aniline and phenoxide nucleophiles.

Kinetic studies are reported of the reactions of 1,3,5-trinitrobenzene with aniline in dimethyl sulfoxide (DMSO). In the presence of buffers containing 1,4- diazabicyclo(2.2.2)octane, (Dabco), and its acid salt, DabcoH(^+), the anilide σ-adduct is formed. The reaction of ethyl 2,4,6-trinitrophenyI ether with aniline in DMSO containing Dabco occurs in two stages. The first gives σ-adduct intermediate on the substitution pathway, which has been identified spectroscopically. The second yields 2,4,6-trinitrodiphenyIamine, the substitution product. Kinetic studies show that proton transfer is rate-limiting both in the formation of the intermediate and in its subsequent acid-catalysed decomposition. Phenoxide is a considerably better leaving group than ethoxide and the substitution reactions of phenyl 2,4,6- trinitrophenyl ethers and phenyl 2,4-dinitronaphthyI ether with aniline in DMSO occur without the accumulation of intermediates. The kinetics indicate both uncatalysed and base catalysed pathways. Values have been determined for the pK(_a) in DMSO of several ammonium ions derived from amines which have previously been widely used as nucleophiles in nucleophilic aromatic substitution reactions; values are also given for four polynitrodiphenylamines used as indicators. Second order rate constants (K(_s)) are presented for the reaction of substituted phenyl 2,4,6-trinitrophenyl ethers with a series of phenolate ions having pK(_a) values both higher and lower than that of the respective leaving groups in aqueous solution. The rate constants for the reverse reaction (k(_-s)) have also been measured. The Brømsted diagram formed when plotting log k(_s) versus pK(_a) shows a change in slope when ΔpK(_a) = 0 (ΔpK(_a) being the difference in pK(_a) values of the leaving group and nucleophile). This is consistent with a two step process involving a discrete σ-adduct intermediate. From the measured β values effective charges have been determined and the overall effective charge map constructed. Kinetic studies have been made for the reactions of substituted phenyl 2,4,6- trinitrophenyl ethers with substituted phenolate ions in 74% DMSO-water (v/v). Two reactions are observed. The evidence suggests that the more rapid involves formation of a 1,1 σ-adduct between the substrate and the phenolate ions. The slower reaction is attributed to hydroxide attack at the 3-position of the substrate

The value of simulation and immersive virtual reality environments to design decision making in new product development

In response to the need to develop more sophisticated, higher quality products product developers are more and more expecting engineering simulations to provide them with the data, information, and knowledge required to make design decisions. Engineering simulations provide insight into the behaviour of virtual product designs and have the capacity to be executed many thousands of times to provide a comprehensive coverage of the solution space being explored. However, engineering simulations are only representative of a reduced set of product properties and are bound by the constraints imposed by the fidelity of the underlying physics of the simulation tools being used. In this paper, we will briefly explore a number of different types of engineering simulation that the Virtual Engineering Centre has been involved in creating and consider the value that the data, information and knowledge that each creates to the decision making process. We will also explore how different visualisation methods being used at the Virtual Engineering Centre support decision making by individuals and groups of people in a design review context. Specifically, we will discuss the use of immersive virtual reality in reviewing simulation results and highlight the limitations of using this technology in group decision making using a case study taken from our work with Bentley Motors. We will conclude that whilst virtual technologies provide opportunities to generate data and information early in the product development process, the ever increasing demands for accuracy and fidelity in representation in mature product sectors outstrips the capability of the technology to fully support decision making in a complete virtual world

What is the new paradigm in product quality?

The current product quality paradigm is founded upon a customer-focused product development process, in which the functionality and behaviour of a product are designed to fulfil the needs of customers, and technological innovation is used to expand the capability and enhance the performance of the product. However, this view of product quality does not reflect the current practices of today's leading manufacturers, who now offer "total solutions" based upon an integrated package of products and services with well defined characteristics tailored to individual needs. Concepts such as globalisation, mass customisation, product branding, e-commerce, and sustainability suggest that a new product quality paradigm is evolving. This paper will discuss our current understanding of product quality issues and outline our vision of the new quality paradigm for product developers

Multi-board concept - a scenario based approach for supporting product quality and life cycle oriented design

This paper will describe the multi-board con-cept, which is a working approach for supporting life cycle oriented design and product quality. Aspects of this concept include construction of a common working environment where multiple display boards depict scenarios of the product life cycle, creating a shared quality mindset amongst designers, and developing creativity and synthesis in product design. The appropri-ateness of scenarios for supporting life cycle oriented design will be argued and prelim-inary results from early experimentation will be presented. Initial results lead us to believe that the multi-board concept promises to be a useful means of communication amongst the design team. We believe that it fosters a thorough understanding of life cycle events, which, in turn, inspires the design of innovative products of the highest quality

Galaxy And Mass Assembly (GAMA): curation and reanalysis of 16.6k redshifts in the G10/COSMOS region

We discuss the construction of the Galaxy And Mass Assembly (GAMA) 10h region (G10) using publicly available data in the Cosmic Evolution Survey region (COSMOS) in order to extend the GAMA survey to z ∼ 1 in a single deg2 field. In order to obtain the maximum number of high precision spectroscopic redshifts we re-reduce all archival zCOSMOS-bright data and use the GAMA automatic cross-correlation redshift fitting code autoz. We use all available redshift information (autoz, zCOSMOS-bright 10k, PRIMUS, VVDS, SDSS and photometric redshifts) to calculate robust best-fitting redshifts for all galaxies and visually inspect all 1D and 2D spectra to obtain 16 583 robust redshifts in the full COSMOS region. We then define the G10 region to be the central ∼1 deg2 of COSMOS, which has relatively high spectroscopic completeness, and encompasses the CHILES VLA region. We define a combined r < 23.0 mag and i < 22.0 mag G10 sample (selected to have the highest bijective overlap) with which to perform future analysis, containing 9861 sources with reliable high-precision VLT-VIMOS spectra. All tables, spectra and imaging are available at http://ict.icrar.org/cutout/G10

Eddington's demon: Inferring galaxy mass functions and other distributions from uncertain data

We present a general modified maximum likelihood (MML) method for inferring generative distribution functions from uncertain and biased data. The MML estimator is identical to, but easier and many orders of magnitude faster to compute than the solution of the exact Bayesian hierarchical modelling of all measurement errors. As a key application, this method can accurately recover the mass function (MF) of galaxies, while simultaneously dealing with observational uncertainties (Eddington bias), complex selection functions and unknown cosmic large-scale structure. The MML method is free of binning and natively accounts for small number statistics and non-detections. Its fast implementation in the R-package dftools is equally applicable to other objects, such as haloes, groups, and clusters, as well as observables other than mass. The formalism readily extends to multidimensional distribution functions, e.g. a Choloniewski function for the galaxy mass-angular momentum distribution, also handled by dftools. The code provides uncertainties and covariances for the fitted model parameters and approximate Bayesian evidences. We use numerous mock surveys to illustrate and test the MML method, as well as to emphasize the necessity of accounting for observational uncertainties in MFs of modern galaxy surveys