Assessing aspects of children's written grammar: automating the process

Teachers are expected to make regular assessments of pupils' writing, providing feedback about their strengths and weaknesses. If the computer could assist teachers in this task by effectively analysing the grammar element in children's writing, then the teacher's work load would be significantly reduced. A computer generated 'text analysis' of grammatical features would have the benefit of providing diagnostic information systematically and efficiently. Although text analysis is not new, it is generally restricted to applications aimed at adults. The development of a quantitative text analysis program, specifically geared to analysing children's writing was therefore considered profitable. This required an understanding of the development of children's writing abilities and the criteria of the National Curriculum levels of attainment for the Standard Assessment Tasks (SATs). Ten grammar features were selected for analysis. Stories reflecting the spread of attainment associated with the end of Key Stage 2 were analysed. The computer successfully distinguished positive and negative grammar features within these texts. Nevertheless, an assessment of qualitative genre details made by teachers will still be required, in order to provide a balanced assessment which includes all elements that contribute to effective writing

Experimental and numerical analysis of a sedimentation forming compressible compacts

Batch sedimentations of the mineral talc suspended in water at various initial concentrations resulted in compacts that displayed compression, and compression with channel formation. During the experiments the local concentration was deduced by means of local electrical resistance measurement. The technique provided concentrations that integrated throughout the vessel to give masses that matched the known initial mass employed to within ±5%. Two types of channel zones were observed: soft and hard, the former appeared to be due to the liquid inertia of water discharging from the latter. The region within and above the soft channel zone diluted from the initial concentration, and this caused the visible interface between the suspension and the supernatant to accelerate. The top of the hard channel zone followed the line of constant solids concentration representing the first significant increase in concentration over the initial suspension. A finite difference numerical model of sedimentation matched the experimental data, including the data determined below the visible interface, with very high precision for the talc suspensions exhibiting compression with insignificant channeling. The implicit model was implemented on a conventional computer spreadsheet package and rapidly converged. The model did not employ a function for hydraulic permeability, instead a linear function between the so-called Kozeny “constant” (or coefficient) and concentration was used. In order to provide an accurate numerical model for compressible sedimentation with significant channel formation, the hydraulic permeability needs to be augmented, or the Kozeny coefficient reduced, and the dilution above the channel zone must be predicted. These should be achieved in a way that is general to all sedimentations of a given type of material, and not specific to only one starting concentration. Experimental and numerical results also indicate that the buoyancy force experienced by the solids is adequately described by the density difference between the solids and the suspending liquid, and not the density difference between the solids and the suspension

Formulation by membrane emulsification

Formulation by membrane emulsificatio

Encapsulation

Encapsulatio

Improving children's written grammar and style: revising and editing with HARRY

Children usually improve their writing in response to teacher comments. HARRY is a computer tutor, designed to assist children improve their narrative writing, focusing particularly upon grammar and style. Providing assistance involved identifying aspects of grammar and style on which to concentrate, including ways to enable the computer to detect weaknesses and then present information concerning how to make improvements. HARRY delivers general, conversational style suggestions for how to revise a text during composition, followed by editing suggestions targeting specific grammar and style weaknesses detected in the text. Finally, spellings and technical errors are corrected in MS Word. Evaluating a writing intervention strategy is problematic, as paradoxically, attempts by children to improve texts, can result in a deterioration in some aspects of writing quality. Four case studies are presented to demonstrate the effects of the HARRY writing system upon children's grammar and style. Each child wrote a control and a HARRY assisted story. HARRY's effectiveness at improving written grammar and style is demonstrated through analyses made of the narratives by CHECK TEXT, a utility tool which calculates and interprets quantitative data. Separate analysis of each stage of the HARRY assisted stories reveals the idiosyncratic pattern of improvement exhibited by each child

Membrane emulsification for the production of uniform poly-N-isopropylacrylamide-coated alginate particles using internal gelation

Alginate particles, crosslinked by calcium ions, have a number of potential biopharmaceutical industry applications due to the biocompatibility of the materials used and formed. One such use is as microcarriers for cell attachment, growth and then detachment without the use of proteolytic enzymes. A straightforward and reproducible method for producing uniform calcium alginate particles with controllable median diameters which employs membrane emulsification and internal gelation (solid particles contained in the dispersed phase) is demonstrated, as well as functionalisation of the resulting beads with amine terminated poly N-isopropylacrylamide (pNIPAM) to form temperature responsive particles, by taking advantage of the electrostatic interaction between the carboxyl groups of the alginate and amino groups of the modified pNIPAM. Cell attachment, growth and detachment capabilities of these core-shell structures were assessed and successfully demonstrated by using phase contrast microscopy and fluorescent staining with calcein-AM and ethidium homodimer-1.The formulation used for the alginate particles avoided non-GRAS chemicals by only using food grade and pharmaceutical grade reagents. The median particle size was controllable within the range between 55. μm and 690. μm and the size distributions produced were very narrow: 'span' values as low as 0.2. When using a membrane pore size of 20. μm no membrane blockage by the suspended calcium carbonate necessary for internal gelation of the alginate particles was observed. Membrane pore openings with diameters of 5 and 10. μm were also tested, but blocked with the 2.3. μm median diameter calcium carbonate solids. © 2014 The Institution of Chemical Engineers

Using statistical and artificial neural networks to predict the permeability of loosely packed granular materials

© 2016 Taylor & FrancisWell-known analytical equations for predicting permeability are generally reported to overestimate this important property of porous media. In this work, more robust models developed from statistical (multivariable regression) and Artificial Neural Network (ANN) methods utilised additional particle characteristics [‘fines ratio’ (x50/x10) and particle shape] that are not found in traditional analytical equations. Using data from experiments and literature, model performance analyses with average absolute error (AAE) showed error of ~40% for the analytical models (Kozeny–Carman and Happel–Brenner). This error reduces to 9% with ANN model. This work establishes superiority of the new models, using experiments and mathematical techniques

Understanding filter cake formation through electrical impedance measurements

An electrical impedance tomography technique for determining the solids concentration in solid/liquid mixtures has been used to analyse cake formation during the pressure leaf filtration of aqueous based mineral suspensions. The experimental data are interpreted through so-called ‘modern filtration theory’ which serves to highlight some of the difficulties that currently exist in the areas of both modelling and scale-up in solid/liquid separation

Aspects of modelling in compressible filter cake formation

Solids concentrations through a solid/liquid mixture were determined using an electrical impedance measuring technique described previously. A number of pressure leaf filter experiments have been performed for two materials exhibiting a range of compressibility at differing applied filtration pressures, initial solids concentrations and surface charges. The paper indicates how such experimental data can be interpreted and modelled using both the classical and so-called ‘modern’ filtration theory. The need to enhance these models for compressible materials is highlighted with reference to the experimental data and the influential particulate and process parameters. Suggestions for the ways in which models can be improved are made

Compressible cake filtration

The formation of a compressible kaolin filter cake has been examined using an electrical conductivity technique that continuously monitors the local solids concentration with height and time during filtration. The relative importance of liquid drag, solids weight and velocity inside a filter cake during the cake forming process were studied, and their effect on the modelling approach of Tiller and Shirato considered. It is concluded that a more accurate representation of the cake concentration profile would result from an incremental simulation of the solid deposition process