Neural Network Modeling of Rheological Parameters of Grouts Containing Viscosity-Modifying Agent

The development of artificial neural network (ANN) models to predict the rheological behavior of grouts is described is this paper and the sensitivity of such parameters to the variation in mixture ingredients is also evaluated. The input parameters of the neural network were the mixture ingredients influencing the rheological behavior of grouts, namely the cement content, fly ash, ground-granulated blast-furnace slag, limestone powder, silica fume, water-binder ratio (w/b), high-range water-reducing admixture, and viscosity-modifying agent (welan gum). The six outputs of the ANN models were the mini-slump, the apparent viscosity at low shear, and the yield stress and plastic viscosity values of the Bingham and modified Bingham models, respectively. The model is based on a multi-layer feed-forward neural network. The details of the proposed ANN with its architecture, training, and validation are presented in this paper. A database of 186 mixtures from eight different studies was developed to train and test the ANN model. The effectiveness of the trained ANN model is evaluated by comparing its responses with the experimental data that were used in the training process. The results show that the ANN model can accurately predict the mini-slump, the apparent viscosity at low shear, the yield stress, and the plastic viscosity values of the Bingham and modified Bingham models of the pseudo-plastic grouts used in the training process. The results can also predict these properties of new mixtures within the practical range of the input variables used in the training with an absolute error of 2%, 0.5%, 8%, 4%, 2%, and 1.6%, respectively. The sensitivity of the ANN model showed that the trend data obtained by the models were in good agreement with the actual experimental results, demonstrating the effect of mixture ingredients on fluidity and the rheological parameters with both the Bingham and modified Bingham models.

Three-photon detachment of electrons from the fluorine negative ion

Absolute three-photon detachment cross sections are calculated for the fluorine negative ion within the lowest-order perturbation theory. The Dyson equation of the atomic many-body theory is used to obtain the ground-state 2p wavefunction with correct asymptotic behaviour, corresponding to the true (experimental) binding energy. We show that in accordance with the adiabatic theory this is crucial for obtaining absolute values of the multiphoton cross sections. Comparisons with other calculations and experimental data are presented.

Oblique amplitude modulation of dust-acoustic plasma waves

Theoretical and numerical studies are presented of the nonlinear amplitude modulation of dust-acoustic (DA) waves propagating in an unmagnetized three component, weakly-coupled, fully ionized plasma consisting of electrons, positive ions and charged dust particles, considering perturbations oblique to the carrier wave propagation direction. The stability analysis, based on a nonlinear Schrodinger-type equation (NLSE), shows that the wave may become unstable; the stability criteria depend on the angle theta between the modulation and propagation directions. Explicit expressions for the instability rate and threshold have been obtained in terms of the dispersion laws of the system. The possibility and conditions for the existence of different types of localized excitations have also been discussed.

Travelling Images, Images of Travel in Nicolas Bouvier's L'Usage du monde

Sketches and photographs are a familiar tool of the traveller-writer, who commonly draws on them when transforming experience into a textual narrative. The verbal thus displaces the visual — the latter retained, if at all, as mere illustration — in ways that echo James Heffernan's definition of ekphrasis as the ‘verbal description of visual representation’. Yet Nicolas Bouvier's 1963 travel narrative L'Usage du monde challenges conventional conceptions of ekphrasis. Juxtaposing the stark ink drawings of Thierry Vernet — Bouvier's travelling companion — with Bouvier's textual narrative, L'Usage du monde shifts representation away from a hierarchical relationship between verbal and visual; it offers instead an account of other cultures that is grounded in polyphony and exchange. This article applies Bouvier's own image of travel as a mosaic to the dual narrative form (or ‘iconotext’, to use Michael Nerlich's term) in order to consider a range of fluid relationships between Bouvier's text and Vernet's drawings. In examining these relationships of amplification, reduction, and absence, the article argues that the plurality of the narrative prompts a rethinking of conventional, binary paradigms of intercultural contact. Ultimately, the iconotextual nature of L'Usage du monde can be interpreted as a metaphor for the processes of cultural translation and transculturation that are central to Bouvier's travelling ethos.

Animal maiming, intimacy and the politics of shared life: the bestial and the beastly in eighteenth- and early nineteenth-century England

The everyday lives of many farm workers in eighteenth- and early nineteenth-century England were intricately and often intimately bound with the lives of animals, the ebb and flow of human life being inseparable from that of animal life. Farmyards, fields, folds as well as barns and stables were all spaces where animals transcended being the mere instruments of capital to instead being obvious co-constituents of the rhythms of existence. Living and working in such close proximity meant that the ‘species barrier’ was crossed and intimacies developed in everyday agricultural practices. Still, the relationship was based upon, if not reducible to, the workings of capital: the animal enrolled as a form of embodied capital, the labourer engaged by the farmer to act upon the animal. And in such relationships intimacies are mirrored by violences: the keeping captive, slaughter, and – occasionally – abuse. In this formative period in which the discourses and policies that continue to inform animal welfare were first formulated, the declining economic and material fortunes of farm workers when juxtaposed to farm animals’ fortune as increasingly ‘cosseted capital’ gave a particular charge to these abuses. Farm animals, and especially horses and cattle, so it is shown, were subjected to a series of violences. Many cases of animal maiming parodied tenderness in their brutality, whilst other attacks on the sexual organs of animals represented complex statements about the ways in which agrarian capitalism regulated all culture. Analysing the changing relationship between humans and animals therefore also helps us to better understand how capitalism mediates – and is mediated by – the non-human as well as the human, and how it defines cultural relations.

The preparation of highly ordered single layer ZSM-5 coating on prefabricated stainless steel microchannels

An elegant way to prepare catalytically active microreactors is by applying a coating of zeolite crystals onto a metal microchannel structure. In this study the hydrothermal formation of ZSM-5 zeolitic coatings on AISI 316 stainless steel plates with a microchannel structure has been investigated at different synthesis mixture compositions. The procedures of coating and thermal treatment have also been optimized. Obtaining a uniform thickness of the coating within 0.5 mm wide microchannels requires a careful control of various synthesis variables. The role of these factors and the problems in the synthesis of these zeolitic coatings are discussed. In general, the synthesis is most sensitive to the H2O/Si ratio as well as to the orientation of the plates with respect to the gravity vector. Ratios of H2O/Si=130 and Si/template=13 were found to be optimal for the formation of a zeolitic film with a thickness of one crystal at a temperature of 130 degreesC and a synthesis time of about 35 h. At such conditions, ZSM-5 crystals were formed with a typical size of 1.5 mu mx1.5 mu mx1.0 mum and a very narrow (within 0.2 mum) crystal size distribution. The prepared samples proved to be active in the selective catalytic reduction (SCR) of NO with ammonia. The activity tests have been carried out in a plate-type microreactor. The microreactor shows no mass transfer limitations and a larger SCR reaction rate is observed in comparison with pelletized Ce-ZSM-5 catalysts; (C) 2001 Elsevier Science B.V. All rights reserved.

IMMUNOCYTOCHEMICAL DEMONSTRATION OF NEUROPEPTIDES IN THE CENTRAL-NERVOUS-SYSTEM OF THE ROUNDWORM, ASCARIS-SUUM (NEMATODA, ASCAROIDEA)

The localization and distribution of neuropeptides in the central nervous system of the pig roundworm, Ascaris suum, have been determined by an indirect immunofluorescence technique in conjunction with confocal microscopy. Antisera to 25 vertebrate peptides and two invertebrate peptides were used to screen the worm for immunoreactivity (IR). Immunostaining was obtained with antisera to pancreatic polypeptide (PP), peptide YY (PYY), neuropeptide Y (NPY), gastrin, cholecystokinin (CCK), substance P (SP), atrial natriuretic peptide (ANP), salmon gonadotropin-releasing hormone (SGnRH), mammalian gonadotropin-releasing hormone (MGnRH), chromogranin A (CGA) and FMRFamide. The most extensive patterns of IR occurred with antisera to PYY, FMRFamide and gastrin. IR was evident in nerve cells and fibres in the ganglia associated with the anterior nerve ring and in the main nerve cords and their commissures; IR to FMRFamide also occurred in the posterior nerve ring. Immunostaining for the other peptides was confined to the nerve cords, with the number of immunoreactive nerve fibres varying from peptide to peptide.