bluuebunny/crossref_metadata_2025 huggingface dataset:
A numerical investigation of the effects of a transverse temperature gradient on the formation of regular and irregular acoustic streaming in an enclosure
Authors: Aktas M K , Ozgumus T
Published: May 2010

The effects of a transverse temperature gradient on the formation of regular and irregular acoustic streaming structures in air-filled, two-dimensional, rectangular, shallow enclosures carrying a longitudinal sound field are investigated numerically. The fluid motion is induced by the harmonic vibration of the enclosure left wall. The fully compressible form of the Navier—Stokes equations is considered to predict the primary oscillatory and secondary pseudo-steady streaming flow fields. An explicit time-marching flux-corrected transport algorithm is used to simulate the acoustic wave formation, propagation, and the resulting flow patterns in the enclosure. The vertical walls of the enclosure are adiabatic whereas the horizontal walls are heated differentially or symmetrically. The transverse temperature gradients are found to strongly affect the acoustic streaming structures and the velocities. The steady streaming velocities significantly increase when the enclosure horizontal walls are asymmetrically heated for both regular and irregular streaming flows. For irregular streaming, the transverse temperature gradients completely change the flow patterns. The irregular streaming velocities are greatly reduced in case of the symmetric temperature increase of the horizontal walls.
A Three-Zone Heat-Release Rate Model for Dual-Fuel Combustion
Authors: Stewart J , Clarke A
Published: May 2010

Dual-fuel engines are modified compression ignition engines, where the primary source of fuel is a gaseous fuel, and ignition is provided by a ‘pilot’ injection of a reduced quantity of diesel. The generally accepted understanding of the dual-fuel engine describes its combustion process as proceeding in three stages. Initially, around half of the pilot will burn and entrain some gaseous fuel into an overall fuel-rich process. Subsequently, the remaining pilot fuel burns and entrains an increasing amount of the primary fuel into its reaction zone. In the final stage, a flame propagation process engulfs the remaining gaseous fuel.

In this article, a three-zone model for the analysis of heat-release rate during the dual-fuel combustion process will be derived. This model will be tested against data obtained for diesel combustion and then applied to experimental data from a dual-fuel test program. It will be shown that there is little evidence to support the generally accepted description of the dual-fuel combustion process in a direct injection engine. The conclusion of this work is that dual-fuel combustion may be better considered as a diesel combustion process, where the gaseous fuel modifies the reaction zone surrounding each igniting droplet of the pilot fuel.
Factors influencing the energy consumption of road freight transport
Authors: Odhams A M C , Roebuck R L , Lee Y J , Hunt S W , Cebon D
Published: May 2010

Key factors that influence the energy consumption of heavy goods vehicles are investigated. These factors include engine efficiency, aerodynamic drag and rolling resistance, vehicle configuration (number of vehicle units), traffic congestion, speed, payload factors, and the use of regenerative braking.

An accurate, validated model of the fuel consumption of a 38 tonne tractor-semitrailer vehicle is used as a basis to derive fuel consumption models of a number of other vehicle configurations. These models included a rigid four-axle truck with maximum gross vehicle mass (GVM) of 26 tonnes; a six-axle tractor semitrailer with GVM of 44 tonnes, with and without regenerative braking; a ‘B-double’ with GVM of 60 tonnes; and an ‘A-double’ with GVM of 82 tonnes. These vehicle models were driven over a simple hypothetical drive cycle with a fixed maximum speed and varying numbers of stops in a 10 km stretch of road.

It is concluded that: (a) improving engine efficiency, unladen mass, rolling resistance, and aerodynamic drag can yield relatively small improvements in fuel consumption, compared with other factors; (b) larger vehicles are always significantly more energy-efficient than smaller ones when fully loaded; (c) transferring freight from articulated vehicles to smaller rigid vehicles for urban deliveries typically increases fuel consumption by approximately 35 per cent; (d) running vehicles partially loaded can increase the energy per unit freight task by up to 65 per cent; and (e) under urban start—stop conditions, the use of regenerative braking systems can reduce heavy vehicle fuel consumption by 25–35 per cent.
Compliance Analysis of Mechanisms with Spatial Continuous Compliance in the Context of Screw Theory and Lie Groups
Authors: Ding X , Dai J S
Published: May 2010

This paper investigates the compliance effect on both serial and parallel mechanisms based on study of deflections of a finite segment of elastic beam with spatial compliance and applies eigenvectors and eigenvalues to identify principal screws in the mechanisms and parallel devices with spatial continuous compliance. With the analysis, compliance characteristics of both serial mechanisms and parallel devices can be identified with effect of compliance. Case studies are presented with numerical examples.
Effects of the thermal conductivity of contact materials on elastohydrodynamic lubrication characteristics
Authors: Kaneta M , Yang P
Published: May 2010

Isothermal elastohydrodynamic lubrication (EHL) theory has brought the improvement in function, performance, and durability of machine elements with concentrated contacts. The main reason is that the theory can evaluate the lubrication characteristics, such as film thickness and pressure distributions, from the shape and size of contacting materials, lubricant viscosity at the entrance to the EHL conjunction, entrainment velocity, equivalent elastic modulus, and applied load. However, in order to estimate the film thickness and pressure distributions more accurately and to make clear the traction behaviour based on lubricant rheology, it is necessary to establish thermal EHL theory, which incorporates heat generation in the fluid film and heat transfer in the machine system on the foundation of isothermal EHL theory. The thermal conductivity of contact materials controls temperature in the fluid film and consequently the lubricant viscosity. Therefore, the EHL characteristics are affected remarkably by the thermal conductivity of contact materials. In this article, the effects of the thermal conductivity of contacting materials on the film thickness, pressure, and traction coefficient are described.
Complexity of Heavy-Payload Forging Manipulator Based on Input/Output Velocity Relationship
Authors: Chu X , Gao F , Guo W , Yan C
Published: May 2010

There are different definitions of complexity in many areas. For a heavy-payload manipulator, the kinematic coupling degree problem, which has much influence on its control and reliability, is very important. This paper proposes a definition of complexity to measure the kinematic coupling degree of a manipulator. After the manipulator's desired output motions in the workshop are obtained, the matrix relating the velocities of actuated joints to the velocities of all basic output motions is calculated. Based on the preceding matrix, the definition of complexity is presented. To illustrate the methods introduced in this paper, four types of heavy-payload forging manipulators (FMs) are analysed, and the type of FM with the smallest complexity is chosen as our prototype.
Rolling contact fatigue prediction for rails and comparisons with test rig results
Authors: Kabo E , Ekberg A , Torstensson P T , Vernersson T
Published: May 2010

Tests in a full-scale roller rig, a full-scale linear test rig, and a twin-disc machine are numerically evaluated and compared in terms of rolling contact fatigue loading. From previously evaluated contact patch sizes, a Wöhler curve relationship is established and matched towards experimentally established fatigue lives. In addition, non-linear finite-element simulations are carried out. Key data needed for the numerical evaluations, as well as difficulties in translating experimental data to numerical models are highlighted. A key parameter here is the interfacial wheel—rail friction. Additional simulations were carried out to establish the latter. However, the conformal contact in the linear test rig makes such simulations very uncertain.
The Calculation of Wheel Impact Force Due to the Interaction between Vehicle and a Turnout
Authors: Sun Y Q , Cole C , McClanachan M
Published: May 2010

It is known that railway turnouts demand more maintenance than other parts of the railway track network because of large impact loads generated by the variation of wheel-rail contact conditions along the turnout and through the crossing. A method using VAMPIRE® modelling to determine the wheel impact forces due to passing turnout has been developed and presented in this article. The simulation shows that both turnout curve and crossing have significant effect on the wheel impact forces; the vertical impact forces from the turnout case are not significantly different from the wheels travelling straight through.
Development and Evaluation of Advanced Wheel Steels to Prevent Wheel Failures in the North American Heavy Haul Operating Environment
Authors: Hernández F C Robles , Kalay S , Anankitpaiboon S , Cummings S
Published: May 2010

This paper presents the results of metallurgical analysis and mechanical and residual stress tests for high performance wheels that are currently under test under 35-metric ton (39 ton) load axles. For this test, eight high performance wheels were tested from various suppliers including an experimental wheel developed by the Transportation Technology Center, Inc. (TTCI) under the Association of American Railroads' Strategic Research Initiatives Programme. All high performance wheels are currently under an accelerated heavy haul test at the TTCI.
Validation of an analysis method for particle image velocimetry of turbulent unsteady flows in turbomachinery
Authors: Cavazzini G , Pavesi G , Ardizzon G
Published: May 2010

This paper presents a post-processing analysis that combines several statistical tools to validate experimental results in a particle image velocimetry analysis on unsteady flows in the turbomachinery field. The method was developed in three steps: verification of the number of acquired images, verification of the meaningfulness of the velocity averages, and identification of the zones characterized by the greatest error on the average estimation. The statistical approach allows one to identify the possible error sources, discriminating between experimental problems due to the test rig, the turbulent nature of the flow, and structures unidentifiable by a single frequency.
Fault diagnosis based on optimized node entropy using lifting wavelet packet transform and genetic algorithms
Authors: Zhang L , Xiong G , Liu H , Zou H , Guo W
Published: May 2010

The current paper presents a novel scheme for bearing fault diagnosis based on lifting wavelet packet transform (LWPT), sample entropy (SampEn), support vector machines (SVMs), and genetic algorithms (GAs). In the proposed scheme, bearing vibration signals were first decomposed into different frequency sub-bands through a four-level LWPT, resulting in a total of 31 node signal components throughout all layers of the LWPT decomposition tree. The SampEns of all 31 components were then calculated as an original feature pool to characterize the complexity of the bearing vibration signals within the corresponding frequency bands. For selecting the most informative features thus reducing the number of features, a GA was applied to simultaneously pick out the salient features and optimize the parameters of SVMs so as to avoid the curse of dimensionality, alleviate computational burden, and improve the subsequent classification. Experiments were conducted on an induction motor with respect to various bearing faults and a range of fault severities. As an example here, three salient features were selected from the original 31 features, with the dimension of features reduced dramatically. The selected three features were then presented into the optimized SVM to identify various bearing conditions. The scheme was compared with the widely used WPT-Energy method and with a neural network classifier with respect to feature extractions and fault classifications, respectively. The results are in favour of the proposed scheme in terms of the feature dimension, number of support vectors, robustness to the data partition, and classification rate.
Defence of homogeneous parallel multi-state systems subject to two sequential attacks
Authors: Hausken K , Levitin G
Published: May 2010

Single and double attacks are compared against a system consisting of identical parallel elements providing performance redundancy in a multi-state system. By destroying elements an attacker tries to maximize the expected damage caused by the reduction of the cumulative system performance. The attacker has a constrained resource which is distributed optimally between two attacks. The optimal number of attacked elements in each attack is determined. The attacker observes which elements are destroyed in the first attack and does not attack them in the second attack. First the optimal attack strategy against a system with a fixed number of elements is analysed. Thereafter a minmax two-period game between the attacker and the defender is considered. The defender distributes its constrained resource between deploying redundant elements and protecting them against the attack in the first period to minimize the expected damage. The attacker chooses its strategies in the second period to maximize the expected damage. A model and a methodology for finding the optimal defence and attack strategies are suggested. Illustrative examples of the optimal attack and defence are presented.
Dirac–Hartree–Fock Perturbation Calculation of Magnetic Shielding Using the External Field-Dependent Restricted Magnetic Balance Condition
Authors: Hamaya Satoru , Fukui Hiroyuki
Published: May 2010

A formulism for four-component Dirac–Hartree–Fock perturbation theory using the restricted magnetic balance (RMB) condition with gauge-including atomic orbitals (GIAOs) is derived at an ab initio level. In this formulation, the zeroth-order Dirac–Hartree–Fock equations are subject only to the usual restricted kinetic balance (RKB) condition, while the external field-dependent RMB condition is introduced in the calculation of the first-order magnetically perturbed orbitals. The magnetic shielding can be divided into a paramagnetic part and a diamagnetic part, as for nonrelativistic (NR) shielding. The present theory is applied to the calculation of hydrogen halide and molecular halogen shieldings.
Functional and molecular analysis of Escherichia coli strains lacking multiple DEAD-box helicases
Authors: Jagessar Kevin L. , Jain Chaitanya
Published: May 2010

DEAD-box RNA helicases are enzymes that unwind RNA duplexes and are found in virtually all organisms. Most organisms harbor multiple DEAD-box helicases, suggesting that these factors participate in distinct aspects of RNA metabolism. To define the individual and collective contribution of the five DEAD-box helicases in the bacterium Escherichia coli (E. coli), nonpolar deletion mutants lacking single or multiple DEAD-box genes were constructed. An analysis of the single-deletion strains indicated that the absence of either the DeaD or SrmB RNA helicase causes growth and/or ribosomal defects under typical laboratory growth conditions. The analysis of strains lacking multiple DEAD-box genes showed cumulative growth defects at low temperatures. A strain deleted for all five DEAD-box genes was also constructed for these studies, representing the first time all DEAD-box genes have been removed in any organism. Additional investigations revealed that the growth and ribosomal defects of such a DEAD-box deficient strain can be sharply attenuated under alternative conditions, indicating that the defects caused by a lack of DEAD-box genes are modulated by growth context.
Branch and Price for WDM Optical Networks with No Bifurcation of Flow
Authors: Raghavan S. , Stanojević Daliborka
Published: May 2010

The second generation of optical networks with wavelength division multiplexing (WDM) is based on the notion of two layer networks, where the first layer represents a logical topology defined over the physical topology of optical fibers and the second layer represents multiple traffic requests combined (multiplexed) over the paths established in the logical topology. Because the design of both of these layers is challenging by itself, researchers have mainly focused on solving these problems either independently or in a sequential fashion. In this paper, we look at the WDM optical network design problem with nonbifurcated traffic flows and propose an exact branch-and-price procedure that simultaneously solves logical topology design and traffic routing over the established logical topology. The unique feature of the proposed algorithm is that it works with a row-incomplete mathematical formulation and two types of variables that exponentially grow in number with the problem size. We discuss computational issues related to the use of this procedure and propose two approximate branch-and-price procedures that can be used to obtain lower and upper bounds for this problem. Finally, we present the results of our computational experiments for two design objectives and alternative optical network settings.
Branch and Price for Large-Scale Capacitated Hub Location Problems with Single Assignment
Authors: Contreras Ivan , Díaz Juan A. , Fernández Elena
Published: May 2010

This paper presents a branch-and-price algorithm for the capacitated hub location problem with single assignment, in which Lagrangean relaxation is used to obtain tight lower bounds of the restricted master problem. A lower bound that is valid at any stage of the column generation algorithm is proposed. The process to obtain this valid lower bound is combined with a constrained stabilization method that results in a considerable improvement on the overall efficiency of the solution algorithm. Numerical results on a battery of benchmark instances of up to 200 nodes are reported. These seem to be the largest instances that have been solved to optimality for this problem.
Monitoring of Biochemical Status in Children with Duarte Galactosemia: Utility of Galactose, Galactitol, Galactonate, and Galactose 1-Phosphate
Authors: Ficicioglu Can , Hussa Christie , Gallagher Paul R , Thomas Nina , Yager Claire
Published: May 2010

Background: Duarte galactosemia (DG) is frequently detected in newborn-screening programs. DG patients do not manifest the symptoms of classic galactosemia, but whether they require dietary galactose restriction is controversial. We sought to assess the relationships of selected galactose metabolites (plasma galactose, plasma galactitol, erythrocyte (RBC) galactitol, RBC galactonate, and urine galactitol and galactonate) to RBC galactose 1-phosphate (Gal-1-P), dietary galactose intake, and neurodevelopmental/clinical outcomes in DG children.

Methods: We studied 30 children 1–6 years of age who had DG galactosemia and were on a regular diet. All participants underwent a physical and ophthalmologic examination and a neurodevelopmental assessment. RBC galactitol, RBC galactonate, RBC Gal-1-P, plasma galactose, plasma galactonate, and urine galactitol and galactonate concentrations were measured.

Results: RBC galactitol and galactonate concentrations were about 2 and 6 times higher, respectively, than control values. Plasma galactose and galactitol concentrations were also about twice the control values. The mean values for RBC Gal-1-P and urine galactitol were within the reference interval. We found a relationship between plasma and urine galactitol concentrations but no relationship between RBC galactose metabolites and urine galactitol. There was a significant relationship between galactose intake and RBC galactose metabolites, especially RBC galactitol (P < 0.0005) and RBC galactonate (P < 0.0005). Galactose intake was not related to the urine galactitol, plasma galactose, or plasma galactitol concentration. RBC galactitol, RBC galactonate, plasma galactose, plasma galactitol, and urine galactonate concentrations showed no relationship with clinical or developmental outcomes.

Conclusions: DG children on a regular diet have RBC Gal-1-P concentrations within the reference interval but increased concentrations of other galactose metabolites, including RBC galactitol and RBC galactonate. These increased concentrations correlate with galactose intake and neither cause any developmental or clinical pathology during early childhood nor oblige a lactose-restricted diet.
New distribution limits ofBassaricyon alleniThomas 1880 and insights on an overlooked species in the Western Brazilian Amazon
Authors: Sampaio Ricardo , Munari Daniel P. , Röhe Fábio , Ravetta André L. , Rubim Paulo , Farias Izeni P. , da Silva Maria N.F. , Cohn-Haft Mario
Published: May 2010

No abstract available
Blinded Independent Central Review of the Progression-Free Survival Endpoint
Authors: Amit Ohad , Bushnell Will , Dodd Lori , Roach Nancy , Sargent Daniel
Published: May 2010

Presented are the efforts of the Pharmaceutical Research and Manufacturing Association PFS Working Group to address concerns related to blinded independent central review of locally evaluated progression times and the proposed audit methodology to minimize potential biases, along with the U.S. Food and Drug Administration's comments on this work.
Development of Rational Drug Combinations with Investigational Targeted Agents
Authors: Clark Adam , Ellis Matthew , Erlichman Charles , Lutzker Stuart , Zwiebel James
Published: May 2010

This manuscript explores specific examples and criteria in which an alternative regulatory process to the existing combination rule would be appropriate and feasible and thus could be adopted by developers.
Assessment of Cancer-Related Neuropathy and Neuropathic Pain
Authors: Cleeland Charles S. , Farrar John T. , Hausheer Frederick H.
Published: May 2010

Cancer-related neuropathic pain syndromes are common and serious complications of a patient's primary malignancy or its treatment, whether by surgery, radiation, or chemotherapy. They may compromise the patient's quality of life as well as their ability to receive effective treatment. In many patients, there may be more than one coexistent neuropathic pain syndrome, posing a diagnostic dilemma that, if unresolved, may result in the institution of therapies that are of limited scope or not targeted at the primary underlying pathophysiology. There is no single adequate diagnostic method that has been established to reliably diagnose or follow patients with cancer-related neuropathic pain syndromes. Clinical assessment of cancer-related neuropathic pain poses some important challenges diagnostically as well as in defining a clear and reliable endpoint assessment in controlled clinical trials. Many different approaches have been applied to the development of assessment or diagnostic tools. Careful review of these methods has been helpful in developing a clearer vision for the future design and refinement of more reliable tools, and more importantly, validation of the clinical utility as well as the reliability of such tools when employed as endpoints in clinical trials focused on prevention, mitigation, or treatment of cancer neuropathic pain.
Pathophysiology and Animal Models of Cancer-Related Painful Peripheral Neuropathy
Authors: Bennett Gary J.
Published: May 2010

There are undoubtedly several causes of painful peripheral neuropathy in cancer patients. Some mechanisms are directly attributable to the tumor; others lie with the therapy, be it surgery, radiation, or chemotherapy. Several animal models have been developed to study the pathophysiological mechanisms that contribute to neuropathic pain. These include inflammation-based models, nerve trauma–induced models, and chemotherapy-induced models of neuropathic pain. My colleagues and I recently identified abnormalities in mitochondrial structure and function in peripheral sensory fibers that are associated with neuropathic pain induced by common chemotherapeutic agents and that can be reversed by agents that enhance mitochondrial function. Our hope is that further identification and clarification of the pathophysiological mechanisms involved at the periphery will help us to develop new classes of medicines and treatment options.
Advances in the Genetics of Familial Renal Cancer
Authors: Morrison Patrick J. , Donnelly Deirdre E. , Atkinson A. Brew , Maxwell Alexander P.
Published: May 2010

Learning Objectives

After completing this couse, the reader will be able to: Apply presymptomatic gene testing to family members with familial renal cancer in order to facilitate earlier diagnosis and treatment for this population.Use genetic testing for timely detection of familial renal cancer in carriers to enable earlier use and increased efficacy of VEGF and mTOR pathway inhibiting drugs.

CME This article is available for continuing medical education credit at CME.TheOncologist.com.

We discuss recent advances in the diagnosis and management of renal cell cancer (RCC) given the enhanced molecular genetics knowledge in this area. A number of hereditary renal cancer syndromes have been described, including von Hippel-Lindau disease, Birt-Hogg-Dubé syndrome, hereditary leiomyomatosis/RCC syndrome, and hereditary papillary renal cancer. Early molecular diagnosis now facilitates the management and prevention of RCC in families. Recommendations for screening in families are discussed.
Current issues of inland water transport in Europe
Authors: Tournaye Cécile , Pauli Gernot , Saha Dieter Michael , van der Werf Hans
Published: May 2010

Inland waterways account for nearly 6% of Europe's transport, with traffic focused on the rhine, Danube, Elbe and Oder river basins. It offers a more environmentally friendly, safe and cost-effective alternative to road transport – as well as a very reliable one – but remains significantly underused. The European Commission adopted a programme for promoting inland water transport in January 2006, including modernising infrastructure and creating efficient links among the various river basins and effective integration in the modal chain. However, as this paper reports, the river commissions rather than Brussels remain the primary drivers for change.
Low-carbon housing design informed by research
Authors: Gillott M. , Rodrigues L. T. , Spataru C.
Published: May 2010

The UK government is committed to cutting greenhouse gas emissions by 80% by 2050 in a bid to tackle climate change. Dwellings in the UK account for approximately 27% of the UK total of carbon dioxide emissions through the burning of fossil fuel for heating, lights and appliances. This includes combustion on the premises, mainly natural gas for heating and cooking, and combustion in power stations to produce electricity for homes. In order to address the climate change contribution from the domestic sector, the UK government has stated that every new home needs to be zero-carbon by 2016. This paper outlines the proposed line of research which will be undertaken on a number of experimental eco-houses constructed at the University of Nottingham. The on-going work will trial and test different construction solutions and sustainable energy technologies. The paper investigates the role that post-occupancy evaluation will play in ensuring that design aspirations are actually met once the dwellings are inhabited. The work also describes the role that phase change materials and earth air heat exchangers may play as thermal mass substitutes in constructive solutions for housing in a warming climate. These solutions and technologies for ensuring occupant comfort and preventing summer overheating in super-insulated dwellings are likely to become increasingly important as UK temperatures rise owing to man-made climate change.
Aspects of vertical drain design: Darcian or non-Darcian flow
Authors: Hansbo S.
Published: May 2010

The classical consolidation equations developed by Barron in 1944 and 1948 are well known among engineers working on soil improvement by preloading in combination with installation of vertical drains. These equations have been gradually refined and are generally utilized in conventional design. The design may seem simple in theory but is connected with a great number of uncertainties from a practical point of view. The problems connected with the choice of consolidation parameters will be commented on and practical advice for the design will be given. In this paper, a number of case records will be presented and compared with, on one hand, the conventional method of design and, on the other hand, the so-called λ method developed by the author in 1960 to take into account the effect of smear. The λ method is based on an exponential correlation between hydraulic gradient and flow velocity. We find that the correlation between the conventional theory and practice, based on back-analysis of field data, is less satisfactory than for the λ method.
The influence of particle characteristics on the behaviour of coarse grained soils
Authors: CAVARRETTA I. , COOP M. , O'SULLIVAN C.
Published: May 2010

This paper describes an experimental study examining the influence of the mechanical and geometrical properties of the constituent grains on the overall material response of cohesionless granular materials. Glass ballotini were used as an analogue soil; their relatively simple geometry allowed the influence of particle shape and inter-particle friction to be examined independently. Techniques were developed to control the surface roughness of the ballotini to facilitate a parametric study. The particle shape was also varied by crushing the ballotini. At the micro-scale, the particle characterisation included accurate measurements of inter-particle friction, contact stiffness, particle surface roughness and particle shape. At the macro-scale the sensitivity of overall material response to changes in surface roughness and geometry was characterised using triaxial tests and oedometer tests on smooth spherical ballotini, roughened ballotini and crushed angular ballotini. Compression tests indicated that the initial load deformation response at particle–particle contact points is significantly softer than previously believed. Optical interferometry of particles after single particle–particle shearing tests confirmed that plastic strains occurred at the contact point, which were related to plastic yield. A Hertzian response was only seen at higher contact loads. A clear relationship between the inter-particle friction and the particle surface roughness was found. However, the macro-scale experiments indicated that while the material response may be slightly dependent on the surface roughness and friction, the influence of particle shape is very much more significant.
Sand grain crushing and interface shearing during displacement pile installation in sand
Authors: YANG Z.X. , JARDINE R.J. , ZHU B.T. , FORAY P. , TSUHA C.H.C.
Published: May 2010

Particle crushing, shear banding, interface abrasion and migration of crushing products all have the potential to influence the behaviour of displacement piles in sands. This paper considers these particulate processes, reporting experiments with model displacement piles installed in uniform pressurised sand and parallel interface ring shear tests. The findings offer new insights into the mechanics of displacement piles in sands.
DEM analysis of soil fabric effects on behaviour of sand
Authors: YIMSIRI S. , SOGA K.
Published: May 2010

The effects of initial soil fabric on the shear behaviour of granular materials are investigated by employing distinct element method (DEM) numerical analysis. Soil specimens are represented by an assembly of non-uniform sized spherical particles. DEM specimens that have different initial contact normal distributions were prepared at two different densities (loose and dense) and then isotropically consolidated triaxial tests were simulated with the following conditions: (a) different drainage conditions (undrained/drained), (b) different modes of shearing (compression/extension), and (c) different directions of shearing (vertical/horizontal). The numerical analysis results are compared qualitatively with the observed experimental data and the effects of initial soil fabric on resulting soil behaviours are discussed. The discussions include the effects of specimen reconstitution methods, effects of large preshearing, and anisotropic characteristics in drained and undrained conditions. The effects of initial soil fabric on the quasi-steady state are also investigated. The numerical analysis results can systematically explain that the observed experimental behaviours of sand are due principally to the effects of initial soil fabric. The outcome provides insights into the observed phenomena in microscopic view.
Varying initial void ratios for DEM simulations
Authors: ABBIREDDY C.O.R. , CLAYTON C.R.I.
Published: May 2010

While many physical experimental methods have been developed to produce different relative densities, and to measure the minimum and maximum void ratios of samples of granular soil, there has been little exploration of techniques for varying the initial void ratio of numerical (e.g. DEM) ‘samples'. This paper reports a series of numerical experiments carried out to explore, for two-dimensional particles, the ranges of initial void ratios that can be achieved on particles of different shape. A tentative proposal is made for a suitable method of producing loose and dense particle packings for DEM simulations. The paper also examines the equivalence of surface undulations and inter-particle friction in affecting void ratio.
Wind effects on the world's tallest reinforced concrete building
Authors: Li Q. S. , Wu J. R. , Fu J. Y. , Li Z. N. , Xiao Y. Q.
Published: May 2010

Field measurements of wind effects on the world's tallest reinforced concrete building (CITIC Plaza, 391 m high) located in Guangzhou were made during Typhoon Damrey in 2005. The field-measured data such as wind speed, wind direction and acceleration responses were simultaneously and continuously measured from the super-tall building during the typhoon. Detailed analysis of the field data was conducted to investigate the wind characteristics and wind-induced vibration of the high-rise structure. Based on the measured acceleration data, amplitude-dependent damping ratios of the building were estimated by the random decrement method. Dynamic characteristics obtained from the field measurements were compared with those calculated from the finite-element model of the structure. The serviceability of the tall building was then analysed based on the field measured results and design codes. Finally, a time–frequency analysis was carried out by the Hilbert–Huang technique to investigate the non-stationary features of the measured wind speed and acceleration response signals. The research output is expected to be of considerable interest and practical use to professionals and researchers involved in the design of super-tall buildings.
Seeking common ground: three perspectives on public space
Authors: Neal Z.
Published: May 2010

Public spaces have been a central concern of urban planners for centuries; more recently they have also captured the attention of sociologists, geographers, political scientists and economists. Focusing on urban public spaces, this review outlines three major perspectives on public space. The legal–economic perspective seeks to answer the most concrete questions about public space (what is it and who pays for it?), thereby laying the definitional and institutional groundwork for other enquiries. The socio-spatial perspective takes the existence of public space for granted and is more concerned with questions of design and application (what does it look like and how is it used?). Finally, the political perspective asks about public space's role in democracy, both abstractly as a site for discursive activities and concretely as a site of exclusion or empowerment. While these three perspectives frequently overlap in practice, they are nonetheless distinguishable in their origins, assumptions and foci. This paper thus serves to illustrate the potential for further cross-disciplinary connections that would enhance understanding of how public space works.
Mapping knowledge flow during sustainability assessment
Authors: Thomson C. S. , El-Haram M. A. , Emmanuel R.
Published: May 2010

Traditionally regarded as a technical process to determine the performance of buildings against sustainability criteria, calls are now emerging for sustainability assessment to be better integrated with the subjectively-based decisions taken across a project lifecycle, to support stakeholder engagement and to promote a culture of learning about sustainability in practice. In order for sustainability assessment fully to realise this wider role, it is necessary to recognise the significance played by knowledge and its flow between stakeholders in the promotion of a common understanding of the actions required to deliver a sustainable urban environment. This paper presents the findings of a knowledge mapping exercise focused on understanding the nature of this flow during application of sustainability assessment within a university campus building project. Knowledge exists in a variety of types and forms; the key sources drawn upon by a key decision-maker were identified and classified. The mapping exercise stressed the significance of supporting the flow of not only explicit sources of knowledge, but also implicit sources such as expert and tacit knowledge. Ensuring that pathways are dynamic and facilitated through effective management to deliver continued engagement between key decision-makers, the rest of the team and wider stakeholders was highlighted as essential.
Urban social sustainability themes and assessment methods
Authors: Colantonio A.
Published: May 2010

In recent years the social dimension (or ‘social sustainability’) has gained increased recognition as a fundamental component of sustainable development. This paper explores the notion of social sustainability and its main assessment methods, together with the pioneering social sustainability framework devised by the City of Vancouver, Canada. The paper illustrates how there is no consensus on the definition of social sustainability because this concept is currently being approached from diverging study perspectives and discipline-specific criteria, making a generalised definition difficult to achieve. In addition, traditional ‘hard’ social sustainability themes such as employment and poverty alleviation are increasingly being complemented or replaced by emerging ‘soft’ and less measurable concepts such as happiness, social mixing and sense of place. Within this context, the paper looks at how Vancouver's local authorities have approached urban social sustainability and discusses the importance of the selection of sustainability principles, objectives, themes, assessment techniques and indicators from a social perspective.
Numerical modelling of the capacity for a complex spillway
Authors: Jacobsen J. , Olsen N. R. B.
Published: May 2010

The stage–discharge curve for a complex spillway geometry has been computed with a three-dimensional numerical model. The model solved the Reynolds-averaged Navier–Stokes equations using the k–ε turbulence model. An orthogonal fixed grid was used, where the cells could be wet, dry or partially wet. A volume-of-fluid method was used to compute the location of the free surface in the grid. The spillway consisted of four partly separated free overflow chambers, with tunnel outlets. The four tunnels joined in a collection tunnel where free surface occurred in some sections and filled the tunnel in others. The resulting stage–discharge curve, therefore, showed two parts: one for low discharges with dominantly free surface flow in the tunnels and another part when the tunnels were filled. The results were compared with a physical model study. The deviation between the computed and measured values of the rating curve were under 2% for most of the curve, but rose to a maximum value of 10% where the flow was most complex. The findings indicate that a three-dimensional numerical model can be an accurate, inexpensive and rapid tool to predict the stage–discharge curve for complex spillways.
Numerical simulation of air–water flow in gated tunnels
Authors: Najafi M. R. , Zarrati A. R.
Published: May 2010

Gated tunnels are among the important hydraulic structures which fulfil various functions. However, due to the high-velocity flow through these structures, critical flow conditions may occur. Generally, physical model studies are performed to optimise the design of these structures which are time consuming and also very expensive. In the present research work a three-dimensional numerical model was used to simulate complicated free-surface air–water flow in gated tunnels. The volume of fluid scheme was used together with the K–ε turbulence model in this simulation. The flow rating curve and air demand downstream of the service gate were computed at different gate openings and were compared with experimental data with good agreement. In addition a comparison of the calculated pressure distribution and cavitation index in the gate chamber with physical measurements showed the accuracy of the computational fluid dynamics model. Furthermore, a comparison of flow pattern and rooster tail formation downstream of the gate with experimental observations showed the capability of the numerical model in simulating the complex air–water flow in high-speed gated tunnels. This study shows the application of numerical simulation as a powerful tool in the design of hydraulic structures.
Supporting (re) Entry to Professional Practice: The SEPP Project
Authors: Baptiste Susan E. , Blais Paulette , Brenchley Christine L. , Sauve Dorianne E. , McMahon Patricia A. , Rangachari Usha
Published: May 2010

Background. During the past decade, there has been an increasing awareness of the challenges affecting internationally educated professionals seeking registration in Canada.Purpose. To describe a project designed to support entry or re-entry to active practice for occupational therapists and physiotherapists who were internationally educated or seeking a return to practice after a prolonged absence.Methods. The major objectives of the project were to develop and evaluate a mentoring network model to support therapists entering or re-entering professional practice in Ontario. Online and other resources were used to enhance professional knowledge and build mentored networks. Supervised placement opportunities were also sought for many participants to meet their learning and integration needs.Results. The project achieved its major objectives and highlighted the challenges faced by individuals seeking to (re)enter professional practice in Ontario.Implications. Project outcomes have wide applications across many health professions.
Piloting a Points-Based Caseload Measure for Community Based Paediatric Occupational and Physiotherapists
Authors: Davidson Kathy F. , Bressler Sandra I.
Published: May 2010

Background. Caseload guidelines and workload management are important issues in recruitment and retention of paediatric rehabilitation therapists.Purpose. This study developed and piloted a points-based caseload questionnaire for paediatric occupational and physiotherapists.Methods. Therapists completed the pilot caseload measure and participated in teleconference focus groups to share their experiences and opinions. Analysis was through descriptive statistics and qualitative analysis.Findings. The data suggested links between caseload point size and various factors such as years of experience, manageability, and client maturity. Focus group feedback supported the use of points rather than numbers as a caseload measure. Participants suggested various uses for the measure and changes to improve ease and consistency in completion.Implications. This caseload measure holds promise, following ongoing research, as a method to standardize caseloads across paediatric settings. As is, it can be used within agencies or by individual therapists seeking a tool of self-reflection and of workload measure.
Mothering Occupations When Parenting Children with Feeding Concerns: A Mixed Methods Study
Authors: Winston Kristin A. , Dunbar Sandra B. , Reed Carol N. , Francis-Connolly Elizabeth
Published: May 2010

Background. The occupations of mothering have gained attention in occupation-based research and literature; however, many aspects of mothering remain unexplored.Purpose. The purpose of this study was to gain insight into mothers' perceptions of their occupations when mothering a child with feeding difficulties.Methods. Study design used mixed methodology utilizing the Parental Stress Scale (PSS), Life Satisfaction Index for Parents (LSTP), and phenomenological interviews.Findings. Comparison of the datasets illuminated the quantitative findings with the words of the women interviewed. Although there was only one statistically significant finding in the quantitative data in terms of satisfaction with leisure and recreation, the qualitative data provided rich descriptions of mothers' perceptions of stress and life satisfaction.Implications. Mixed methods data analysis revealed the complex nature of the interaction between mothering occupations and mothering a child with feeding concerns as well as how these concerns might influence occupational therapy practice.
Adults' Uses of Computer Technology: Associations with Literacy Tasks
Authors: Smith M Cecil , Smith Thomas J.
Published: May 2010

The present study examined data from a large, nationally representative sample—the National Assessment of Adult Literacy (NCES, 2007)—to examine how computer use and Internet-based literacy practices (use of e-mail, searching for information on the Internet, and Internet chatting) were related to prose, document, and quantitative literacy scores. The moderating effects of gender and ethnicity with these practices were also assessed. Results indicated that, when controlling for potential confounding variables, the use of computers and engagement in Internet-based literacy practices was associated with higher scores on each of the three literacy tasks. Additionally, moderating effects were identified for gender and for ethnicity on several literacy tasks.
An Examination of One-to-One Computing in the Middle School: Does Increased Access Bring about Increased Student Engagement?
Authors: Donovan Loretta , Green Tim , Hartley Kendall
Published: May 2010

This study explores configurations of laptop use in a one-to-one environment. Guided by methodologies of the Concerns-Based Adoption Model of change, an Innovation Configuration Map (description of the multiple ways an innovation is implemented) of a 1:1 laptop program at a middle school was developed and analyzed. Three distinct configurations showed a range in fidelity of laptop integration at the school. A second finding showed a range of off-task behaviors as part of each configuration. We chose to more deeply explore if a relationship between the individual configurations and student off-task behaviors existed. We found that increased access to laptop computers does not always equate to increased student engagement. Implications of this study extend to teachers, school administrators, and teacher educators.