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Reynolds
Terms modified by Reynolds Selected AbstractsTest,retest effects in treatment studies of reading disability: the devil is in the detailDYSLEXIA, Issue 4 2007Genevieve McArthur Abstract Reynolds and Nicolson (Dyslexia, 2007; 13: 78,96) claim to show that the ,dyslexia dyspraxia attention-deficit treatment' (DDAT) benefits children with reading difficulties. However, Rack, Snowling, Hulme, and Gibbs (Dyslexia, 2007; 13: 97,104) argue that because this study did not include an untrained control group then ,all that needs to be postulated to explain the results reported is that children improve their scores on the DST screening tests simply as a result of repeated testing on the same activities' (p. 102). How likely is it that the linguistic gains reported by Reynolds and Nicolson (Dyslexia, 2007; 13: 78,96) are due to test,retest effects? The results of previous exercise- and auditory-based treatment studies that included an untrained control group suggest that test,retest effects explain gains on around 50% of real-word reading tests, 33% of phonological recoding tests, 33% of phonological awareness tests, 17,25% of spoken language tests, and 15% of spelling tests. In addition, longer periods of time between test and retest sessions are associated with test,retest effects on measures of reading but not spoken language. These findings suggest that two of the four linguistic gains reported by Reynolds and Nicolson (Dyslexia, 2007; 13: 78,96) are due to test,retest effects (phonemic segmentation and working memory). The remaining two tests are measures of spoken language and not reading. Hence, the data reported by Reynolds and Nicolson (Dyslexia, 2007; 13: 78,96) are not sufficient to support DDAT as an effective treatment for children with reading difficulties. Copyright © 2007 John Wiley & Sons, Ltd. [source] Follow-up of an exercise-based treatment for children with reading difficultiesDYSLEXIA, Issue 2 2007David Reynolds Abstract This study reports the results of a long-term follow-up of an exercise-based approach to dyslexia-related disorders (Reynolds, Nicolson, & Hambly, Dyslexia, 2003; 9(1): 48,71). In the initial study, children at risk of dyslexia were identified in 3 years of a junior school. One half then undertook a 6 month, home-based exercise programme. Evaluation after 6 months indicated that the exercise group improved significantly more than the controls on a range of cognitive and motor skills. Critics had suggested that the improvement might be attributable to artifactual issues including Hawthorne effects; an initial literacy imbalance between the groups; and inclusion of non-dyslexic participants. The present study evaluated the issue of whether the gains were maintained over the following 18 months, and whether they were in some sense artifactual as postulated by critics of the original study. Comparison of (age-adjusted) initial and follow-up performance indicated significant gains in motor skill, speech/language fluency, phonology, and working memory. Both dyslexic and non-dyslexic low achieving children benefited. There was also a highly significant reduction in the incidence of symptoms of inattention. Interestingly there were no significant changes in speeded tests of reading and spelling, but there was a significant improvement in (age-adjusted) reading (NFER). It is concluded that the gains were indeed long-lasting, and that the alternative hypotheses based on potential artifacts were untenable, and that the exercise treatment therefore achieved its applied purpose. Further research is needed to determine the underlying reasons for the benefits. Possible (and potentially synergistic) explanations include: improved cerebellar function (neural level); improved learning ability and/or attentional ability (cognitive level); improved self-esteem and self-efficacy (affective level); and improved parental/familial support (social level). Copyright © 2006 John Wiley & Sons, Ltd. [source] Science, sophistry and ,commercial sensitivity': Comments on ,evaluation of an exercise-based treatment for children with reading difficulties', by Reynolds, Nicolson and HamblyDYSLEXIA, Issue 3 2003Ian L. Richards First page of article [source] Measurement mischief: A critique of Reynolds, Nicolson and Hambly (2003)DYSLEXIA, Issue 3 2003Chris Singleton Abstract Reynolds, Nicolson and Hambly (2003) report an intervention study of the effects of exercise-based training on literacy development, using literacy measures from the Dyslexia Screening Test (DST), the NFER-Nelson Group Reading Test, and the Standard Assessment Tasks (SATs). Investigation of the nature and psychometric characteristics of these measures casts serious doubt on their appropriateness in a study of this nature. Consideration of the findings obtained using these measures does not support the authors' conclusion that reading was improved by the intervention. The study by Reynolds et al. does not demonstrate that exercise-based treatment improves literacy skills and the use of its purported findings as evidence that exercise-based treatment would be beneficial for children with literacy difficulties is scientifically untenable. Copyright © 2003 John Wiley & Sons, Ltd. [source] An experimental study on the ripple,dune transitionEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2001André Robert Abstract Flume experiments were conducted on different bed stages across the ripple,dune transition. As flow velocity increases, an initially flat bed surface (made of fairly uniform sandy material) is gradually transformed into a two-dimensional rippled bed. With further increase in velocity, two-dimensional ripples are replaced by irregular, linguoid ripples. As the average velocity necessary for the ripple,dune transition to occur is imposed on the bed surface, these non-equilibrium linguoid ripples are further transformed into larger, two-dimensional dunes. For each of these stages across the transition, a concrete mould of the bed was created and the flow structure above each fixed bed surface investigated. An acoustic Doppler velocimeter was used to study the flow characteristics above each bed surface. Detailed profiles were used along a transect located in the middle of the channel. Results are presented in the form of spatially averaged profiles of various flow characteristics and of contour maps of flow fields (section view). They clearly illustrate some important distinctions in the flow structure above the different bedform types associated with different stages during the transition. Turbulence intensity and Reynolds stresses gradually increase throughout the transition. Two-dimensional ripples present a fairly uniform spatial distribution of turbulent flow characteristics above the bed. Linguoid ripples induce three-dimensional turbulence structure at greater heights above the bed surface and turbulence intensity tends to increase steadily with height above bed surface in the wake region. A very significant increase in turbulence intensity and momentum exchange occurs during the transition from linguoid ripples to dunes. The turbulent flow field properties above dunes are highly dependent on the position along and above the bed surface and these fields present a very high degree of spatial variability (when compared with the rippled beds). Further investigations under natural conditions emphasizing sediment transport mechanisms and rates during the transition should represent the next step of analysis, together with an emphasis on quadrant analysis. Copyright © 2001 John Wiley & Sons, Ltd. [source] Fluid flow and heat transfer of opposing mixed convection adjacent to downward-facing, inclined heated platesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 1 2009Kenzo Kitamura Abstract Experimental investigations were carried out for opposing mixed convective flows of air adjacent to downward-facing, inclined heated plates. The experiments covered the ranges of the Reynolds and modified Rayleigh numbers from ReL=400 to 4600 and RaL*=1.0×107 to 5.4×108, and the inclination angles from ,=15 to 75° from horizontal. The flow fields over the plates were visualized with smoke. The results showed that a separation of forced boundary layer flow occurs first at the bottom edge of the plate, and then the separation point shifts toward upstream with increasing wall heat flux, and finally, reaches the top edge of the plates. It was found that the separations at the bottom and top edges are predicted with a non-dimensional parameter (GrL,*/ReL2.5)=0.35 and 1.0, respectively. The local heat transfer coefficients of the inclined plates were also measured and the results showed that the minimum coefficients appear in the separation region. Moreover, it was revealed that forced, natural, and combined convective flows can be classified by the non-dimensional parameter (GrL,*/ReL2.5). © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Pub- lished online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20233 [source] Heat transfer of combined forced and natural convection from horizontal cylinder to airHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2007Kenzo Kitamura Abstract Experimental investigations have been carried out for combined convective flows of air induced around uniformly heated, horizontal cylinders. Three cases of aiding, opposing, and cross flows were examined. The experiments covered the ranges of the Reynolds and modified Rayleigh numbers of Red=50 to 900 and Rad*=5×104 to 3×106. The flow fields around the cylinders were visualized with smoke. The results showed that separation points gradually shift from those of the forced convection to the top edge of the cylinder with increasing wall heat fluxes. The local heat transfer coefficients of the cylinders were also measured. Although the local coefficients show complex variations with the forced flow velocities and the wall heat fluxes, the overall coefficients become higher than those estimated from pure forced and natural convections throughout the cases of aiding, opposing, and cross flows. Moreover, it was confirmed that the overall Nusselt numbers as well as the separation points can be predicted with the non-dimensional parameter (Grd*/NudRed2). © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(8): 474,488, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20180 [source] An unsteady flow structure on a heated rotating disk under mixed convectionHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2005Noriyuki Furuichi Abstract A flow field under mixed convection on a heated rotating disk has been measured using an ultrasonic velocity profiler (UVP). The measured velocity field is a spatio-temporal one as a function of radial coordinates and time. The objective of this paper is to clarify the vortex structure caused by the instability between buoyancy and centrifugal force. The vortex appears under typical conditions of Reynolds numbers and Grashof numbers and it moves toward the outside of the disk. This behavior can be classified into two patterns. The size of the vortex structure decreases with an increasing Reynolds number and increases with the Grashof number. The traveling velocity of the vortex increases with the Grashof number. Moreover, it decreases with an increasing Reynolds number in spite of increasing centrifugal force. According to these results, the region dominated by natural, forced, and mixed convection is classified in the relationship between Reynolds and Grashof numbers. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(6): 407,418, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20074 [source] Edward Sexby, John Reynolds and Edmund Chillenden: Agitators, ,sectarian grandees' and the relations of the New Model Army with London in the spring of 1647*HISTORICAL RESEARCH, Issue 191 2003Michael A. Norris This article seeks to revise our view of the connections between the New Model Army and London at the time of its so-called revolt in the spring of 1647. Specifically, it is concerned with identifying the author(s) responsible for a series of important documents that have been traditionally attributed to Trooper Edward Sexby. A re-reading of key sources suggests that a group of high-ranking officers channelled soldierly concerns for the payment of arrears and indemnity into principled resistance of parliamentary orders for their disbandment. Working through the agency of Captain John Reynolds and Lieutenant Edmund Chillenden, these officers appear to have sponsored the activities of the emerging Agitator movement. [source] The Historiography of a Construct: "Feudalism" and the Medieval HistorianHISTORY COMPASS (ELECTRONIC), Issue 3 2009Richard Abels Between 1974 and 1994, two influential critiques of feudalism were published, an article in 1974 by Elizabeth A. R. Brown and a book by Susan Reynolds in 1994, that crystallized doubts about the construct of feudalism harbored by many historians of the Middle Ages. Over the last few years textbooks have begun to reflect the new consensus. Medieval historians responsible for chapters on the Middle Ages in Western Civilization and World Civilization textbooks now shy away from the term ,feudalism'. This reticence is less evident in civilization textbooks lacking a medievalist among the collaborators. In several of these we still find the ,feudal Middle Ages' presented without apology, as well as comparisons drawn between Japanese, Chinese, and medieval Western feudalisms. Whether or not the assigned textbook mentions ,feudalism', most Western civilization instructors probably continue to use the term because it is familiar to them and to their students. This article presents an overview of the historiography of one of the key concepts for the study of the Middle Ages, and an assessment of where the state of the question now stands. The author concludes that, although the critique of feudalism is powerful and necessary, the pendulum is threatening to swing too far in the other direction, away from the vertical ties and power relations that once dominated discussions of medieval politics and society, and toward a new paradigm of horizontal bonds, consensus making, and community. [source] Viscous flow in three-dimensional reconstructed porous mediaINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2003Marco Pilotti Abstract In a recent paper Masad et al. (Int. J. Numer. Methods Eng. 2000; 26: 53,74) have shown the possibility of numerically studying fluid flow within two-dimensional microscopic images of granular materials. In this paper we investigate the possibility of computing the flow field at the pore scale within numerically reconstructed three dimensional porous media, by coupling a physically based sedimentation algorithm for porous media generation and a Lattice Boltzmann Technique for solving Navier equations for the monophasic flow of a newtonian fluid inside the intergranular space. Since the adopted sedimentation algorithm can produce porous media with a controlled level of complexity, we believe that this type of approach provides an ideal numerical laboratory to probe the effect of void space topology and geometry on the flow field. This should allow to understand the fluid-dynamic implications of processes such as compaction and cementation. After showing that the Lattice Boltzmann Technique is effective in solving Navier equations in porous media also at moderately high Reynolds, where Darcy's flow does not strictly hold anymore, we investigate the distribution of velocity components within porous media of growing complexity, starting from two different periodic arrangements of spheres up to a mixture of log-normally distributed spheres. We observe that the distribution of velocity components is conditioned by the medium complexity and tends to an exponential pattern. Copyright © 2003 John Wiley & Sons, Ltd. [source] Turbulence modelling of problem aerospace flowsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2006Paul G. Tucker Abstract Unsteady Reynolds averaged Navier,Stokes (URANS) and detached eddy simulation (DES) related approaches are considered for high angle of attack NACA0012 airfoil, wing,flap, generic tilt-rotor airfoil and double-delta geometry flows. These are all found to be problem flows for URANS models. For DES fifth-order upwinding is found too dissipative and the use of, for high speed flows, instability prone centred differencing essential. An existing hybrid ILES,RANS modelling approach, intended for flexible geometry, relatively high numerical dissipation codes is tested along with differential wall distance algorithms. The former gives promising results. The standard turbulence modelling approaches are found to give perhaps a surprising results variation. Results suggest that for the problem flows, the explicit algebraic stress and Menter shear stress transport (SST) URANS models are more accurate than the economical Spalart,Allmaras (SA). However, the explicit algebraic stress model (EASM) in its k,, form is impractically expensive to converge. Here, SA predictions lack a rotation correction term and this is likely to improve these results. Copyright © 2005 John Wiley & Sons, Ltd. [source] Numerical methods for large-eddy simulation in general co-ordinatesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2004Gefeng Tang Abstract Large scale unsteady motions in many practical engineering flows play a very important role and it is very unlikely that these unsteady flow features can be captured within the framework of Reynolds averaged Navier,Stokes approach. Large-eddy simulation (LES) has become, arguably, the only practical numerical tool for predicting those flows more accurately since it is still not realistic to apply DNS to practical engineering flows with the current and near future available computing power. Numerical methods for the LES of turbulent flows in complex geometry have been developed and applied to predict practical engineering flows successfully. The method is based on body-fitted curvilinear co-ordinates with the contravariant velocity components of the general Navier,Stokes equations discretized on a staggered orthogonal mesh. For incompressible flow simulations the main source of computational expense is due to the solution of a Poisson equation for pressure. This is especially true for flows in complex geometry. A multigrid 3D pressure solver is developed to speed up the solution. In addition, the Poisson equation for pressure takes a simpler form with no cross-derivatives when orthogonal mesh is used and hence resulting in increased convergence rate and producing more accurate solutions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Prediction of unsteady, separated boundary layer over a blunt body for laminar, turbulent, and transitional flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2004D. Scott Holloway Abstract The focus of this paper is to study the ability of unsteady RANS-based CFD to predict separation over a blunt body for a wide range of Reynolds numbers particularly the ability to capture laminar-to-turbulent transition. A perfect test case to demonstrate this point is the cylinder-in-crossflow for which a comparison between experimental results from the open literature and a series of unsteady simulations is made. Reynolds number based on cylinder diameter is varied from 104 to 107 (subcritical through supercritical flow). Two methods are used to account for the turbulence in the simulations: currently available eddy,viscosity models, including standard and realizable forms of the k,, model; and a newly developed eddy,viscosity model capable of resolving boundary layer transition, which is absolutely necessary for the type and range of flow under consideration. The new model does not require user input or ,empirical' fixes to force transition. For the first time in the open literature, three distinct flow regimes and the drag crisis due to the downstream shift of the separation point are predicted using an eddy,viscosity based model with transition effects. Discrepancies between experimental and computational results are discussed, and difficulties for CFD prediction are highlighted. Copyright © 2004 John Wiley & Sons, Ltd. [source] URANS computations for an oscillatory non-isothermal triple-jet using the k,, and second moment closure turbulence modelsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 9 2003M. Nishimura Abstract Low Reynolds number turbulence stress and heat flux equation models (LRSFM) have been developed to enhance predictive capabilities. A new method is proposed for providing the wall boundary condition for dissipation rate of turbulent kinetic energy, ,, to improve the model capability upon application of coarse meshes for practical use. The proposed method shows good agreement with accepted correlations and experimental data for flows with various Reynolds and Prandtl numbers including transitional regimes. Also, a mesh width about 5 times or larger than that used in existing models is applicable by using the present boundary condition. The present method thus enhanced computational efficiency in applying the complex turbulence model, LRSFM, to predictions of complicated flows. Unsteady Reynolds averaged Navier,Stokes (URANS) computations are conducted for an oscillatory non-isothermal quasi-planar triple-jet. Comparisons are made between an experiment and predictions with the LRSFM and the standard k,, model. A water test facility with three vertical jets, the cold in between two hot jets, simulates temperature fluctuations anticipated at the outlet of a liquid metal fast reactor core. The LRSFM shows good agreement with the experiment, with respect to mean profiles and the oscillatory motion of the flow, while the k,, model under-predicts the mixing due to the oscillation, such that a transverse mean temperature difference remains far downstream. Copyright © 2003 John Wiley & Sons, Ltd. [source] A block-implicit numerical procedure for simulation of buoyant swirling flows in a model furnaceINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2003Marcelo J. S. de Lemos Abstract This work reports numerical results for the case of incompressible laminar heated flow with a swirl in a vertical cylindrical chamber. Computations are obtained with a point-wise block-implicit scheme. Flow governing equations are written in terms of the so-called primitive variables and are recast into a general form. The discretized momentum equations are applied to each cell face and then, together with the mass-continuity, tangential velocity and energy equations, are solved directly in each computational node. The effects of Rayleigh, Reynolds and Swirl numbers on the temperature field are discussed. Flow pattern and scalar residual history are reported. Further, it is expected that more advanced parallel computer architectures can benefit from the error smoothing operator here described. Copyright © 2003 John Wiley & Sons, Ltd. [source] Coupled lubrication and Stokes flow finite elementsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2003Matthew S. Stay Abstract A method is developed for performing a local reduction of the governing physics for fluid problems with domains that contain a combination of narrow and non-narrow regions, and the computational accuracy and performance of the method are measured. In the narrow regions of the domain, where the fluid is assumed to have no inertia and the domain height and curvature are assumed small, lubrication, or Reynolds, theory is used locally to reduce the two-dimensional Navier,Stokes equations to the one-dimensional Reynolds equation while retaining a high degree of accuracy in the overall solution. The Reynolds equation is coupled to the governing momentum and mass equations of the non-narrow region with boundary conditions on the mass and momentum flux. The localized reduction technique, termed ,stitching,' is demonstrated on Stokes flow for various geometries of the hydrodynamic journal bearing,a non-trivial test problem for which a known analytical solution is available. The computational advantage of the coupled Stokes,Reynolds method is illustrated on an industrially applicable fully-flooded deformable-roll coating example. The examples in this paper are limited to two-dimensional Stokes flow, but extension to three-dimensional and Navier,Stokes flow is possible. Copyright © 2003 John Wiley & Sons, Ltd. [source] Evaluation of Smagorinsky-based subgrid-scale models in a finite-volume computationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 6 2002Petri Majander Abstract Smagorinsky-based models are assessed in a turbulent channel flow simulation at Reb=2800 and Reb=12500. The Navier,Stokes equations are solved with three different grid resolutions by using a co-located finite-volume method. Computations are repeated with Smagorinsky-based subgrid-scale models. A traditional Smagorinsky model is implemented with a van Driest damping function. A dynamic model assumes a similarity of the subgrid and the subtest Reynolds stresses and an explicit filtering operation is required. A top-hat test filter is implemented with a trapezoidal and a Simpson rule. At the low Reynolds number computation none of the tested models improves the results at any grid level compared to the calculations with no model. The effect of the subgrid-scale model is reduced as the grid is refined. The numerical implementation of the test filter influences on the result. At the higher Reynolds number the subgrid-scale models stabilize the computation. An analysis of an accurately resolved flow field reveals that the discretization error overwhelms the subgrid term at Reb=2800 in the most part of the computational domain. Copyright © 2002 John Wiley & Sons, Ltd. [source] Predictions of future climate change in the caribbean region using global general circulation modelsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 5 2007Moises E. Angeles Abstract Since the 1800s the global average CO2 mixing ratio has increased and has been related to increases in surface air temperature (0.6 ± 0.2 °C) and variations in precipitation patterns among other weather and climatic variables. The Small Island Developing States (SIDS), according to the 2001 report of the Intergovernmental Panel on Climate Change (IPCC), are likely to be among the most seriously impacted regions on Earth by global climate changes. In this work, three climate change scenarios are investigated using the Parallel Climate Model (PCM) to study the impact of the global anthropogenic CO2 concentration increases on the Caribbean climate. A climatological analysis of the Caribbean seasonal climate variation was conducted employing the National Center for Environmental Prediction (NCEP) reanalysis data, the Xie,Arkin precipitation and the Reynolds,Smith Sea Surface Temperature (SST) observed data. The PCM is first evaluated to determine its ability to predict the present time Caribbean climatology. The PCM tends to under predict the SSTs, which along with the cold advection controls the rainfall variability. This seems to be a main source of bias considering the low model performance to predict rainfall activity over the Central and southern Caribbean. Future predictions indicate that feedback processes involving evolution of SST, cloud formation, and solar radiative interactions affect the rainfall annual variability simulated by PCM from 1996 to 2098. At the same time two large-scale indices, the Southern Oscillation Index (SOI) and the North Atlantic Oscillation (NAO) are strongly related with this rainfall annual variability. A future climatology from 2041 to 2058 is selected to observe the future Caribbean condition simulated by the PCM. It shows, during this climatology range, a future warming of approximately 1 °C (SSTs) along with an increase in the rain production during the Caribbean wet seasons (early and late rainfall seasons). Although the vertical wind shear is strengthened, it typically remains lower than 8 m/s, which along with SST > 26.5 °C provides favorable conditions for possible future increases in tropical storm frequency. Copyright © 2006 Royal Meteorological Society [source] Benjamin Ralph's School of Raphael (1759): Praise for Hogarth and a Direct Source for ReynoldsJOURNAL FOR EIGHTEENTH-CENTURY STUDIES, Issue 1 2001BERND KRYSMANSKI First page of article [source] Improving the prediction of liquid back-mixing in trickle-bed reactors using a neural network approachJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2002Simon Piché Abstract Current correlations aimed at estimating the extent of liquid back-mixing, via an axial dispersion coefficient, in trickle-bed reactors continue to draw doubts on their ability to conveniently represent this important macroscopic parameter. A comprehensive database containing 973 liquid axial dispersion coefficient measurements (DAX) for trickle-bed operation reported in 22 publications between 1958 and 2001 was thus used to assess the convenience of the few available correlations. It was shown that none of the literature correlations was efficient at providing satisfactory predictions of the liquid axial dispersion coefficients. In response, artificial neural network modeling is proposed to improve the broadness and accuracy in predicting the DAX, whether the Piston,Dispersion (PD), Piston,Dispersion,Exchange (PDE) or PDE with intra-particle diffusion model is employed to extract the DAX. A combination of six dimensionless groups and a discrimination code input representing the residence-time distribution models are used to predict the Bodenstein number. The inputs are the liquid Reynolds, Galileo and Eötvos numbers, the gas Galileo number, a wall factor and a mixed Reynolds number involving the gas flow rate effect. The correlation yields an absolute average error (AARE) of 22% for the whole database with a standard deviation on the AARE of 24% and remains in accordance with parametric influences reported in the literature. © 2002 Society of Chemical Industry [source] Effects of fish size, time-to-fatigue and turbulence on swimming performance: a case study of Galaxias maculatusJOURNAL OF FISH BIOLOGY, Issue 6 2003V. I. Nikora A simple relationship for the inanga Galaxias maculatus swimming velocity is suggested and tested in low and high turbulence channels. The relationship connects the swimming velocity with fish Reynolds and Froude numbers and can be used in both ecological analysis (e.g. habitat requirements) and management strategies (e.g. fishways design). Contrary to some previous studies and intuition, effects of turbulence on swimming performance appeared to be negligible. The most likely explanation for this result relates to mechanics of fish,turbulence interactions that may be dependent on both the turbulence scales and energy. The data suggest that future studies of turbulence effects on fish behaviour should involve, in addition to turbulence energetics, consideration of fish dimensions in relation to the spectrum of turbulence scales. [source] RADIO FREQUENCY (RF) HEATING OF STARCH SOLUTIONS UNDER CONTINUOUS FLOW CONDITIONS: EFFECT OF SYSTEM AND PRODUCT PARAMETERS ON TEMPERATURE CHANGE ACROSS THE APPLICATOR TUBEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2002G.B. AWUAH ABSTRACT Studies were conducted to evaluate the effect of system and product parameters on the temperature change (,T) across a 1.5 kW radio frequency heater operating at 27.12 MHz. Starch solutions (1 to 4% w/w) were used at three different flow rates (0.35, 0.5 and 1 L/min) and four power levels (672, 912, 1152 and 1392 W). The average heating rate of starch solutions varied from 6 to 19C/min depending on flow rate, concentration and power level. The corresponding residence time varied from 1.5 to 4.3 min. Central composite designs involving power (830 to 1234 W) and starch concentration (1 to 4% w/w) at 0.5 L/min were used to study the effects of salt, pH and sugar. As expected fluid flow rate, power level and salt concentration had significant impact (P ± 0.05) on temperature change (,T) across the applicator tube. Although the interaction effect of salt and concentration influenced ,T (P < 0.05), observed trends were not clear cut. Sugar and pH had no significant (P >0.05) influence on ,T due probably to their relatively lower conductivities. However, the interaction effect of sugar and starch concentration affected ,T. Correlations were developed for estimating ,T across the tube as a function of power level, concentration, pH, added salt and sugar. Finally, dimensionless correlations involving the generalized Reynolds, Prandtl, Grashof numbers, dimensionless power and loss-factor ratios were developed for estimating the temperature ratio (U) across the RF applicator. [source] Two-scale continuum model for simulation of wormholes in carbonate acidizationAICHE JOURNAL, Issue 12 2005Mohan K. R. Panga Abstract A two-scale continuum model is developed to describe transport and reaction mechanisms in reactive dissolution of a porous medium, and used to study wormhole formation during acid stimulation of carbonate cores. The model accounts for pore level physics by coupling local pore-scale phenomena to macroscopic variables (Darcy velocity, pressure and reactant cup-mixing concentration) through structure-property relationships (permeability-porosity, average pore size-porosity, and so on), and the dependence of mass transfer and dispersion coefficients on evolving pore scale variables (average pore size and local Reynolds and Schmidt numbers). The gradients in concentration at the pore level caused by flow, species diffusion and chemical reaction are described using two concentration variables and a local mass-transfer coefficient. Numerical simulations of the model on a two-dimensional (2-D) domain show that the model captures the different types of dissolution patterns observed in the experiments. A qualitative criterion for wormhole formation is developed and it is given by , , O(1), where , = . Here, keff is the effective volumetric dissolution rate constant, DeT is the transverse dispersion coefficient, and uo is the injection velocity. The model is used to examine the influence of the level of dispersion, the heterogeneities present in the core, reaction kinetics and mass transfer on wormhole formation. The model predictions are favorably compared to laboratory data. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] DIEL VARIATIONS IN OPTICAL PROPERTIES OF IMANTONIA ROTUNDA (HAPTOPHYCEAE) AND THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE) EXPOSED TO DIFFERENT IRRADIANCE LEVELS,JOURNAL OF PHYCOLOGY, Issue 3 2008Sébastien Mas Diel variations of cellular optical properties were examined for cultures of the haptophyte Imantonia rotunda N. Reynolds and the diatom Thalassiosira pseudonana (Hust.) Hasle et Heimdal grown under a 14:10 light:dark (L:D) cycle and transferred from 100 ,mol photons · m,2 · s,1 to higher irradiances of 250 and 500 ,mol photons · m,2 · s,1. Cell volume and abundance, phytoplankton absorption coefficients, flow-cytometric light scattering and chl fluorescence, and pigment composition were measured every 2 h over a 24 h period. Results showed that cell division was more synchronous for I. rotunda than for T. pseudonana. Several variables exhibited diel variability with an amplitude >100%, notably mean cell volume for the haptophyte and photoprotective carotenoids for both species, while optical properties such as flow-cytometric scattering and chl a,specific phytoplankton absorption generally showed <50% diel variability. Increased irradiance induced changes in pigments (both species) and mean cell volume (for the diatom) and amplified diel variability for most variables. This increase in amplitude is larger for pigments (factor of 2 or more, notably for cellular photoprotective carotenoid content in I. rotunda and for photosynthetic pigments in T. pseudonana) than for optical properties (a factor of 1.5 for chl a,specific absorption, at 440 nm, in I. rotunda and a factor of 2 for the absorption cross-section and the chl a,specific scattering in T. pseudonana). Consequently, diel changes in optical properties and pigmentation associated with the L:D cycle and amplified by concurrent changes in irradiance likely contribute significantly to the variability in optical properties observed in biooptical field studies. [source] The effectiveness of a peer support camp for siblings of children with cancer,PEDIATRIC BLOOD & CANCER, Issue 5 2006Ranita Sidhu BSc OT Abstract Background Siblings of children with cancer have higher levels of psychological stress and adaptational difficulties compared to siblings of healthy children and children with other chronic illness. This is the first study to report on the mental health of Australian siblings of children with cancer and examines the effects of a therapeutic peer support camp,Camp Onwards, as an intervention. Procedure A protocol, designed to reduce levels of distress, improve social competence, and improve knowledge about the impact of cancer and its treatment was developed. Siblings (n,=,26) 8,13 years were assessed using standardised self-report measures pre and post intervention and at ,8 weeks follow-up with: the Behaviour Assessment for Children (BASC) (Reynolds & Kamphaus, 1992), Self Perception Profile for Children (SPP-C) (Harter, 1985), Sibling Perception Questionnaire (SPQ) (Carpenter & Sahler, 1991). Results Change was measured using paired t tests. At pre-test, 40% of the sample demonstrated increased levels of emotional distress when compared to the normal population. Post intervention, siblings reported lower levels of distress demonstrated by decreased anxiety (P,=,0.01) and positive changes in the Self Report of Personality [BASC] (P,=,0.00). Improved social competence was noted in the interpersonal domain of the SPQ (P,=,0.01) and also greater social acceptance scores on the SPP-C (P,=,0.01). Improved knowledge about the impact of cancer and its treatment was evidenced by significant reductions in the fear of disease domain on the SPQ (P,=,0.01). Conclusions Siblings who attended Camp Onwards demonstrated improved mental health outcomes that were sustained at follow-up, demonstrating its effectiveness as an intervention strategy in supporting sibling adjustment. Pediatr Blood Cancer 2006; 47:580,588. © 2005 Wiley-Liss, Inc. [source] Psychosocial functioning of pediatric renal and liver transplant recipientsPEDIATRIC TRANSPLANTATION, Issue 5 2008Yelena P. Wu Abstract:, The current study examined child- and parent-reported child psychosocial functioning in a large sample of children who received solid organ transplantation. Participants included 64 children who received kidney or liver transplantation and 64 parents who completed a standardized measure of children's psychosocial functioning (BASC; Reynolds & Kamphaus, 1992). Although post-transplant children reported significantly fewer psychosocial difficulties than the normative average, parents reported that children had some psychosocial difficulties, particularly internalizing problems. There were no differences in psychosocial functioning between deceased donor organ and living donor organ recipients. Given the discrepancy between parent and child report, the results suggest that children may underreport psychosocial difficulties following transplantation or parents may over-report children's difficulties. Clinicians and researchers are encouraged to obtain assessment information from multiple reporters when assessing psychosocial functioning in this population. [source] Online Recruiting and Selection: Innovations in Talent Acquisition by Douglas H. Reynolds and John A. WeinerPERSONNEL PSYCHOLOGY, Issue 3 2010Article first published online: 5 AUG 2010 No abstract is available for this article. [source] A comparison of algebraic Reynolds stress models for the prediction of the turbulent flow inside a turbomachine rotorPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Marco Antonello Dr. An algebraic Reynolds stress model has been developed and tested simulating the turbulent flow inside a centrifugal impeller. The prediction of the model are compared with those of other algebraic turbulent stress models, in order to analyse the capability of properly account for effects such as flow curvature, flow separation, and solid wall rotation. [source] The relationship between social support and student adjustment: A longitudinal analysisPSYCHOLOGY IN THE SCHOOLS, Issue 7 2005Michelle Kilpatrick Demaray This study is an examination of the relationship of perceived social support and adolescents' adjustment behaviors over time. The sample (n = 82) included students from two at-risk urban middle schools. Utilizing two measures, the Child and Adolescent Social Support Scale (CASSS; C. K. Malecki, M. K. Demaray, & S. N. Elliott, 2000) and the Behavior Assessment System for Children, Self Report of Personality (BASC; C. R. Reynolds & R. W. Kamphaus, 1998), data were collected at three time points. Results point to a relationship between social support and student adjustment behaviors over time. Specifically, support from parents was related to clinical maladjustment and emotional symptoms one year later. In fact, parent support was still related to clinical maladjustment one year later even after students' earlier levels of clinical maladjustment were taken into account. Parent support was also related to personal adjustment in the short term (6 months). Classmate support was related to students' emotional symptoms one year later. Finally, school support was related to school maladjustment one year later even after students' earlier school maladjustment was taken into account. Implications for school psychologists are discussed. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 691,706, 2005. [source] | ||||||||||||||||||||||||||||