Accessory child safety harnesses: Do the risks outweigh the benefits?

Accessory child safety harnesses are available in some countries as alternative restraints for young children or as an accessory restraint used with booster seats. Their use, in Australia at least, is becoming more common. There have been concerns that the risk of misuse of these restraints outweighs any potential benefit this system might have over a retractable lap-shoulder belt system used with a booster seat. However to date there is no evidence to confirm or deny this. This study used laboratory simulated frontal crash tests to examine the performance of accessory child safety harness systems compared to the lap-shoulder belt when used alone and when used with two common designs of Australian booster seat. The performance of the child safety harness system when misused was also investigated. The results demonstrate that the correctly used child safety harness system performed no better than the lap-shoulder system, and in fact allows for a greater risk of submarining. Furthermore, one common form of child safety harness misuse, where the harness is over-tightened causing the lap belt to be positioned high over the abdomen, allowed extremely undesirable dummy motion. This involved gross submarining and direct contact between the harness system and the dummy's neck. These findings suggest that the risks associated with accessory child safety harness systems most likely outweigh any potential benefits, in frontal impacts at least.     

Future horizons in building environmental engineering

The paper brings together many current themes of interest and stimulates the reader to be aware that in creative work there has to be something beyond technical competence; there has to be a committed energy, desire and love in the work being created. The author confirms that buildings modify climate; they influence behaviour and culture; they affect the distribution of resources and the ecological pattern of our planet, whilst human aspirations can only be met when climate, buildings and people are in balance.     

An Ultrafine,Water-Based Condensation Particle Counter and its Evaluation under Field Conditions

An ultrafine, water-based condensation particle counter (U-WCPC, TSI Model 3786) has been compared to a butanol-based ultrafine counter (U-BCPC, TSI Model 3025) for measurement of atmospheric and freeway-tunnel aerosols. The U-WCPC utilizes a warm, wet-walled growth tube to activate and grow particles through water condensation in a laminar-flow. It has an aerosol sampling rate of 0.3 L/min, and a nominal detection limit near 3 nm. Several field comparisons were made to the butanol-based instrument with the same nominal detection limit. For measurements of size-selected aerosols with diameters of 5 nm and larger the two instruments generally agreed, with a mean response within 5%. At 3 nm particle size differences were observed, and these differences varied with the data set. Measurements of ambient aerosol in Boulder, Colorado showed higher counting efficiency at 3 nm with the U-BCPC, while in a California freeway tunnel the opposite trend was observed, with higher counting efficiencies at 3 nm observed by the U-WCPC. For direct measurement of atmospheric aerosols, the two types of instruments yielded equivalent concentrations, independent of particle number concentration.     

Performance prediction of a proton exchange membrane fuel cell using the ANFIS model

In this study, the performance (current–voltage curve) prediction of a Proton Exchange Membrane Fuel Cell (PEMFC) is performed for different operational conditions using an Adaptive Neuro-Fuzzy Inference System (ANFIS). First, ANFIS is trained with a set of input and output data. The trained model is then tested with an independent set of experimental data. The trained and tested model is then used to predict the performance curve of the PEMFC under various operational conditions. The model shows very good agreement with the experimental data and this indicates that ANFIS is capable of predicting fuel cell performance (in terms of cell voltage) with a high accuracy in an easy, rapid and cost effective way for the case presented. Finally, the capabilities and the limitations of the model for the application in fuel cells have been discussed.     

Application of Gate Turn-Off Thyristors in 460-V 7.5-250-hp AC Motor Drives

A 7.5-250-hp range of variable-frequency ac motor drives has been under development at the Westinghouse R & D Center since early in 1981. Design and performance details for prototype equipment rated for 10, 20, and 50 hp will be discussed. The drive system comprises a three-phase thyristor controlled ac/dc converter in conjunction with a dc/ac adjustable-frequency inverter using gate turn-off thyristors (GTO's). The output of the inverter is a six-step voltage wave in the range of 6-120 Hz, suitable for driving three-phase ac induction or synchronous motors. Details of the inverter design, including means to protect the gate turn-off thyristors from output line-to-line or line-to-ground short circuits, will be given special attention.     

The physiology of flatfish chromatophores

Most flatfish, of the order Pleuronectiformes, possess a white lower side, and a brown or grey upper side. This upper side can display integumentary patterning with dark areas and colored or white spots. Chromatophores in flatfish are dermal and epidermal melanophores, as well as dermal xanthophores, erythrophores, iridophores, and leucophores, combinations of which contribute to the color and patterning. Cellular studies demonstrate pattern-related differences in numerical distribution between the types of chromatophores, and in their size, both of which will enhance contrast between areas of the pattern. As well as these morphological characteristics, there are also clear physiological differences, with melanophores from various areas of the patterns demonstrating differential responsiveness to background and to stress/excitement stimuli. Regulation of flatfish melanophore responses is predominantly neural, through the sympathetic nervous system; the pituitary hormones in these fish function in maintaining final equilibria in physiological adaptations to backgrounds. Melanophores from main components of patterns also respond differently in vitro to electrical stimulation, to pituitary hormones, and to sympathomimetic drugs and their antagonists. Sensitivity characteristics with alpha- and beta-adrenergic pharmacological reagents in vitro indicate the existence of a pattern-related balance in alpha- and beta-adrenoceptor mediation in melanophore regulation. The patterning mechanism is complex, with both morphological and physiological differences at the chromatophore level, as well as involvement of central processing and control, which remains to be analysed.     

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)