Mass transfer and flow in electrically charged micro- and nanochannels

In this work, the fluid flow and mass transfer due to the presence of an electric field in a rectangular channel is examined. We consider a mixture of water or another neutral solvent and a salt compound, such as sodium chloride, for which the ionic species are entirely dissociated. Results are produced for the case in which the channel height is much greater than the electric double layer (EDL) (microchannel) and for the case in which the channel height is of the order of the width of the EDL (nanochannel). Both symmetric and nonsymmetric velocity, potential, and mole fraction distributions are considered, unlike previous work on this problem. At small electrolyte concentrations, the Debeye-Huckel picture of the electric double layer is recovered; at larger concentrations, the Gouy-Chapman picture of the electric double emerges naturally. The numerical results presented here agree with analytical solutions of a singular perturbation analysis, which is valid as the channel height increases. In the symmetric case for the electroosmotic flow so induced, the velocity field and the potential are similar. In the asymmetric case corresponding to different wall potentials, the velocity and potential can be vastly different. The fluid is assumed to behave as a continuum, and the volume flow rate is observed to vary linearly with channel height for electrically driven flow, in contrast to pressure-driven flow, which varies as height cubed. This means that very large pressure drops are required to drive flows in small channels. However, useful volume flow rates may be obtained at a very low driving voltage.     

Textual case-based reasoning for spam filtering: a comparison of feature-based and feature-free approaches

Spam filtering is a text classification task to which Case-Based Reasoning (CBR) has been successfully applied. We describe the ECUE system, which classifies emails using a feature-based form of textual CBR. Then, we describe an alternative way to compute the distances between cases in a feature-free fashion, using a distance measure based on text compression. This distance measure has the advantages of having no set-up costs and being resilient to concept drift. We report an empirical comparison, which shows the feature-free approach to be more accurate than the feature-based system. These results are fairly robust over different compression algorithms in that we find that the accuracy when using a Lempel-Ziv compressor (GZip) is approximately the same as when using a statistical compressor (PPM). We note, however, that the feature-free systems take much longer to classify emails than the feature-based system. Improvements in the classification time of both kinds of systems can be obtained by applying case base editing algorithms, which aim to remove noisy and redundant cases from a case base while maintaining, or even improving, generalisation accuracy. We report empirical results using the Competence-Based Editing (CBE) technique. We show that CBE removes more cases when we use the distance measure based on text compression (without significant changes in generalisation accuracy) than it does when we use the feature-based approach.     

Basic processes in reading: Can functional phonological recoding be blocked?

A widely held view is that phonological processing is always involved in lexical access from print, and is automatic in that it cannot be prevented. This claim was assessed in the context of a priming paradigm. In Experiment 1, repetition priming was observed for both pseudohomophone-word pairs (e.g., brane-brain) and morphologically related word pairs (e.g., marked-mark) in the context of lexical decision. In Experiment 2, subjects searched the prime for the presence of a target letter and then made a lexical decision to a subsequent letter string. Phonological priming from a pseudohomophone was eliminated following letter search of the prime, whereas morphological priming persisted. These results are inconsistent with the claim that a) lexical access from print requires preliminary phonological processing, and b) functional phonological processing cannot be blocked. They are, however, consistent with the conclusion that, for intact skilled readers, lexical access can be accomplished on the basis of orthographic processing alone. These results join a growing body of evidence supporting the claim that there exist numerous points in visual word recognition at which processing can be stopped. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neighborhood effects in reading aloud: New findings and new challenges for computational models.

A word from a dense neighborhood is often read aloud faster than a word from a sparse neighborhood. This advantage is usually attributed to orthography, but orthographic and phonological neighbors are typically confounded. Two experiments investigated the effect of neighborhood density on reading aloud when phonological density was varied while orthographic density was held constant, and vice versa. A phonological neighborhood effect was observed, but not an orthographic one. These results are inconsistent with the predominant role ascribed to orthographic neighbors in accounts of visual word recognition and reading aloud. Consistent with this interpretation, 6 different computational models of reading aloud failed to simulate this pattern of results. The results of the present experiments thus provide a new understanding of some of the processes underlying reading aloud, and new challenges for computational models. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A knowledge-based system for the recycling of non-hazardous industrial residuals in civil engineering applications

Abstract: It is estimated that 4.6 billion tons of non‐hazardous solid waste materials are produced annually in the USA. The potential reuse for a portion of the materials in the construction of highways and roads suggests that valuable benefits in terms of economic and environmental gains are possible. This paper describes the development of a prototype computer‐assisted tool or expert system to help manufacturers assess and analyze their industrial residuals as potential road construction material. This represents an expansion in the application of intelligent systems to domains where a few, hard‐to‐find technical reports have represented the main source of expertise available to practitioners for years. The system, developed through the use of an object‐oriented software shell, Level5 Object, was designed in a user‐friendly Windows environment which allows users with little or no computer training to effectively evaluate material residuals.     

Strengths, Weaknesses, Opportunities, and Threats for Foreign-Invested Construction Enterprises: A China Study

China has been attracting overseas construction enterprises with its vast expanding business market. The country is further opening its construction market to overseas businesses as the result of its accession to the World Trade Organization in 2001. In line with this development, there are an increasing number of foreign-invested construction enterprises (FICEs) entering into the market. Using Porter’s competitiveness factor analysis method, this paper identifies the FICEs’ strengths, weaknesses, opportunities, and threats in the Chinese construction market. Data used in the analysis stem from multiple sources including statistical reports, literature review, regulations and policies, and interviews with construction professionals. These findings should provide a valuable reference for overseas construction enterprises who are interested in developing business in the Chinese construction market.     

The severity of drunken driving as perceived by drunken drivers

Men convicted of drunken driving rated this particular offence as significantly less serious than men from a control group who had no convictions for drunken driving offences. Instead of shame and guilt feelings preventing the person from committing further acts of drunken driving, prosecution and court appearance seems to have a detrimental effect on the offender's attitudes to this type of criminal behaviour.     

Electrical analogue for a partial differential equation

The electrical analogue provides a useful approach to the solution of Partial Differential Equations. A general purpose analogue for PDEs would be a useful peripheral for a small digital computer, enabling it to handle quickly, cheaply and with reasonable accuracy problems which otherwise require substantial computational time on large machines.In this paper the author discusses the design of an analogue for ?²U + U_x = 0, suitable for further extension as a computer controlled general analogue. It is shown that AC networks, using capacitors as passive elements, offer substantial advantages over other analogues. The use of buffer amplifiers at each node greatly simplifies the unilateral impedance problem, but introduces unidirectional error components. These errors are analysed, and specifications for suitable amplifiers are obtainedExperimental results on small (20 node, 90 node) models confirm the satisfactory performance of the analogue, and the author predicts that large scale (> 900 nodes) models will yield results accurate to better than 99.9%, with less than 100 ms settling times