bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical investigation of the spin‐up of a two‐layer fluid
Authors: Mang J. , Ungarish M. , Schaflinger U. 
Published: March 2011

AbstractThe spin‐up of a two‐layer fluid with a free surface in a cylindrical container rotating about a vertical axis is investigated numerically, using axisymmetric finite differences. As Linden & van Heijst (1984) have shown, the flow inside the viscous boundary layer at the bottom leads to the accumulation of the heavier lower‐layer fluid near the side wall. Thereby, a bare spot in which the light fluid is in direct contact with the bottom is formed around the axis. The present simulation gives new insight into the internal structures and interaction of the two fluids. Preliminary results indicate strong mixing inside the region of heavy fluid.
Universal wall‐boundary conditions for turbulence‐transport models
Authors: Rung T. , Lübcke H. , Thiele F. 
Published: March 2011

AbstractIn the industrial design process of fluids engineering devices, the use of numerical simulation is of ever increasing importance. The predictive quality of such simulations is often governed by the representation of turbulence. Virtually all industrial simulations mimic the influence of turbulence by a closure model based on transport equations for statistical turbulence properties. Besides the derivation of such transport‐equation models, the adequate formulation of wall‐boundary conditions has come into the focus of attention. Conventional boundary conditions rely on the validity of specific flow conditions pertaining to the wall‐shear stress and the resolution properties of the computational grid in the wall‐adjacent region. Since the shear stress is part of the simulation result, this approach—strictly speaking—requires the anticipation of the solution. Moreover, it significantly affects the efficiency and flexibility of the simulation due to the associated mesh constraints. The principal aim of this research is the development of a universal boundary condition. Examples included show encouraging results for attached and separated flows.
Creeping Newtonian Film Flow Down an Inclined Wavy Plane. Part I
Authors: Scholle M. , Wierschem A. , Aksel N. 
Published: March 2011

AbstractTheoretical investigations are made on the influence of a sinusoidal bottom topography on a gravity driven, Newtonian film flow. Neglecting inertia effects the surface shape is obtained for small amplitudes of the bottom profile using perturbation theory. For thick films and large bottom amplitudes an exact analytical approach is developed.
An eddy viscosity scaled dynamic scale similarity model
Authors: Wagner C. 
Published: March 2011

AbstractA new subgrid scale model for Large Eddy Simulations (LES) of wall‐bounded turbulent flows, which is based on scale similarity between resolved stresses and subgrid scale stresses, is proposed. Testing this model a posteriori, the fully developed turbulent channel flow was simulated for a low Reynolds number (based on the channel height H and friction velocity uT) of Re = 360. Additionally a coarse direct numerical simulation (DNS) without model and a LES with a dynamic Smagorinsky model were performed. Excellent agreement is obtained applying the new model in comparison with Kim et al.'s ]2[ DNS data base.
Inexact Newton‐Krylov Methods for Nonlinear Forced Heat Convection Problems by BEM
Authors: Hriberšek M. 
Published: March 2011

AbstractA preconditioned inexact Newton‐Krylov nonlinear iterative method is constructed for computation of nonlinear heat transfer problems by Boundary Element Methods. The performance of the iterative method is tested on conjugate heat transfer problem in a thick wall channel.
Instability of buoyant‐thermocapillary flows in non‐cylindrical liquid bridges
Authors: Nienhüser Ch. , Kuhlmann H. C. , Rath H. J. 
Published: March 2011

AbstractThe flow driven by buoyancy and thermocapillarity in a liquid bridge between coaxial differentially heated disks held by surface tension forces is investigated. We numerically determine the stability of axisymmetric flows by a linear stability analysis. In the present approach, the influence of buoyancy forces on the flow stability is taken into account through static meniscus deformations as well as through internal buoyancy. To elucidate the physical instability mechanisms the energy balance given by Reynolds‐Orr‐like equations is considered term by term.
Plane channel flow with heat transfer: Stability analysis with a commercial CFD‐code
Authors: Severin J. , Beckert K. , Herwig H. 
Published: March 2011

AbstractSpatial development of small amplitude disturbances in plane Poiseuille flow is investigated numerically using a commercial CFD code (CFX 4.2). Small amplitude Tolmien‐Schlichting waves known from an Orr‐Sommerfeld analysis are superimposed as initial conditions on a fully developed laminar channel flow. The downstream spatial disturbances are calculated on the basis of the full Navier‐Stokes equations (NSE). Results are compared to calculations based on the Orr‐Sommerfeld equations (OSE). In a second step the thermal energy equation is solved in addition to the NSE to investigate temperature effects and especially the development of temperature disturbances.
A multi‐phase soil model including a soil‐foundation interface
Authors: Ehlers W. , Blome P. 
Published: March 2011

AbstractIn the present contribution, the frictional material soil is considered within the well‐founded framework of the Theory of Porous Media ]1–3[. The model represents a multi‐phase medium consisting of a solid skeleton, a pore‐liquid (here water) and a pore‐gas (here air). Concerning the solid skeleton, a general elasto‐plasticity approach including a soil‐foundation interface is presented. In particular, to describe granular soils like sand, a physically non‐linear soil elasticity law ]4[ is taken into consideration. In the plastic domain, use is made of the single‐surface yield function by Ehlers ]2[, which is extended towards isotropic work‐hardening materials.
Direct numerical simulation of three‐dimensional flame instabilities
Authors: Gerlinger W. , Schneider K. , Bockhorn H. 
Published: March 2011

AbstractThe evolution of premixed gas flames near extinction and stability limits is of primary interest for many applications in combustion technology. Under such conditions the flames are very sensitive, and exhibit quasi‐steady state behaviour so that they are well‐suited to determine flammability limits. We show three‐dimensional numerical simulation of the transient behaviour of lean H2‐air flames. The thermo‐diffusive equations are solved by means of a parallelized Fourier‐pseudospectral code. We compute the evolution of freely propagating spherical flames, whereby the influence of the initial flame radius is investigated. The results exhibit different behaviour as found in experimental studies under microgravity conditions, i.e. the splitting due to cellular instabilities, extinction, and stationary flame balls.
3D simulations of turbulent deflagrations using dynamic grid adaptation
Authors: Huld Thomas , Wilkening Heinz 
Published: March 2011

AbstractWe present a CFD code for simulating turbulent deflagrations in gas mixtures for studies of explosion accidents. A dynamic grid adaptation method is used to increase the accuracy of the calculation in regions of interest, such as at flame and shock fronts. The numerical simulations compared with experimental data and is shown to yield strongly improved results at at modest cost in computational time.
Computations of NOx Emissions of Domestic Boilers
Authors: Thévenin D. , Gicquel O. , Darabiha N. 
Published: March 2011

AbstractDue to severe regulations concerning pollutant emissions, practical devices using combustion to release energy must be designed from the start using accurate, predictive numerical tools. A partially premixed methane/air flame in a two‐dimensional configuration is investigated in this work. This configuration is close to those used in real domestic gas boilers. The flame structure and flow pattern are calculated using complex chemistry and detailed transport models. A post‐processing method is then used to predict NO emission.Computations are performed for two configurations. The two cases have the same primary and secondary mass flow‐rates and equivalence ratio. The only difference between them is the introduction of an insert inside the primary injector.Both results have been compared to measurements. Calculations are found to be in good agreement with the flame shapes observed experimentally. The classical burner shows a Bunsen‐type flame while the one with an insert has a totally different shape (butterfly‐type flame). NO emission levels are also well predicted in both configurations. The butterfly flame induces a reduction in NO emission. This reduction seems to be due to the increased mixing between the burnt gases and the secondary air jet, which homogenizes the temperature distribution and reduces the maximum temperature.
On Noncoercive Models in the Theory of Inelastic Deformations with Internal Variables
Authors: Krzysztof Chelmiski 
Published: March 2011

AbstractIn the theory of inelastic deformations with internal variables, H.‐D. Alber has defined an important class of models called models of monotone type. For the subclass containig coercive models, the existence of global in time solutions is known. Unfortunately, in practice the coerciveness condition fails very often. Therefore we consider here noncoercive problems. In this note we study a subclass of models of monotone type for which the so‐called coercive approximation converges to a solution of the original noncoercive problem.
On the Model Chan‐Bodner‐Lindholm in the Theory of Inelastic Deformation
Authors: Piotr Gwiazda 
Published: March 2011

AbstractWe prove global in time existence and uniqueness of large solutions for a problem in the nonlinear theory of inelastic deformations with internal variables for nonhomogeneous boundary conditions. The proof is based on the nonlinear nonautonomous semigroup method.
How to scale reconstruction filters in 2D‐computerized tomography
Authors: Rieder A. 
Published: March 2011

AbstractThe state‐of‐the‐art reconstruction algorithm in 2D tomography is the filtered backprojection algorithm. The quality of the reconstructed density function depends crucially on the proper scaling of the reconstruction filter in relation to the discretization step size. We show how to do it the right way in the parallel scanning geometry.
The Alpha‐1 Association Genetic Counseling Program: An Innovative Approach to Service
Authors: McGee Dawn , Strange Charlie , McClure Rebecca , Schwarz Laura , Erven Marlene 
Published: March 2011

AbstractIn an era of specialty medicine, genetic counselors are becoming increasingly focused in their service provision. The Alpha‐1 Association Genetic Counseling Program, established in September 2007, specializes in confidential toll‐free genetic counseling provided by a certified genetic counselor for Alpha‐1 Antitrypsin deficiency, a co‐dominant condition associated with lung and/or liver disease. The program received more than 600 callers in its first 2 years. Sixty‐seven percent of new callers were family members, carriers, or health professionals. The number of callers increased between the first 2 years, with the greatest increases being family members and health professionals. Testing options and explanation of results encompassed 60% of initial reasons for calls. Seventy‐two percent of referrals came from family and friends, test result letters, and the Alpha‐1 Association. Between year 1 and 2 family member referrals showed the largest increase. This disease‐specific genetic counseling program provides a model that may be useful for other rare disease communities.
Detection of point landmarks in 3D medical images via phase congruency model
Authors: Ferrari Ricardo J. , Allaire Stéphane , Hope Andrew , Kim John , Jaffray David , Pekar Vladimir 
Published: March 2011

Abstract
This paper presents a novel technique for detection of point landmarks in volumetric medical images based on a three-dimensional (3D) Phase Congruency (PC) model. A bank of 3D log-Gabor filters is specially designed in the frequency domain and used to compute 3D energy maps, which are further combined to form the phase congruency measure. The PC measure is invariant to intensity variations and contrast resolution and provides a good indication of feature significance in an image. To detect significant 3D point landmarks, eigen-analysis of a 3×3 matrix of second-order PC moments, computed for each point in the image, is performed followed by local maxima detection. Two different application scenarios in radiation therapy planning of the head and neck anatomy are used to illustrate the feasibility and usefulness of the proposed method.
A two-step method for estimating QTL effects and positions in multi-marker analysis
Authors: MA WEIJUN , ZHOU YING , ZHANG SHUANGLIN 
Published: March 2011

SummaryQuantitative trait is always controlled by multiple latent genetic loci, and genetic markers have been used to map quantitative trait loci (QTLs) auxiliarily. The method of multiple interval mapping (MIM) provides an appropriate way for mapping QTL using genetic makers. However, the computation in the MIM seems infeasible for a large number of marker intervals. Nowadays, the Dantzig selector (DS) method proves to be a more efficient method to estimate model effects in a linear model when the number of parameters is (much) larger than the sample size, which has not been applied to genetic mapping for QTL. In this paper, we developed a two-step method for mapping QTL based on the MIM, and we also illustrate the feasibility of adopting the DS to estimate marker or QTL effects. Simulation results showed that the proposed method performed satisfactorily well by comparisons with the existing MIM method, and the analysis to real data set also tested the practicability and efficiency of the DS method in genetic mapping.
Cryptosporidiumcell culture infectivity assay design
Authors: KING B. J. , KEEGAN A. R. , ROBINSON B. S. , MONIS P. T. 
Published: March 2011

SUMMARYMembers of the genusCryptosporidium, which cause the gastrointestinal disease cryptosporidiosis, still represent a significant cause of water-borne disease worldwide. While intensive efforts have been invested in the development of techniques for parasite culture,in vitrogrowth has been hampered by a number of factors including low levels of infectivity as well as delayed life-cycle development and poor synchronicity. In this study we examined factors affecting the timing of contact between excysted sporozoites and target host cells and the subsequent impact of this upon the establishment of infection. We demonstrate that excystation rate impacts upon establishment of infection and that in our standard assay format the majority of sporozoites are not close enough to the cell monolayer when they are released from the oocyst to successfully establish infection. However, this can be easily overcome by centrifugation of oocysts onto the cell monolayer, resulting in approximately 4-fold increases in sporozoite attachment and subsequent infection. We further demonstrate that excystation procedures can be tailored to control excystation rate to match the assay end purpose and that excystation rate can influence data interpretation. Finally, the addition of both a centrifugation and washing step post-sporozoite attachment may be appropriate when considering the design ofin vitroculture experiments for developmental analysis and stage-specific gene expression as this appears to increase the synchronicity of early developmental stages.
The sensuous music aesthetics of the Middle Ages: the cases of Augustine, Jacques de Liège and Guido of Arezzo
Authors: Hentschel Frank 
Published: March 2011

ABSTRACTUsing well-known texts by Augustine, Jacques de Liège and Guido of Arezzo, this article tries to show that, despite prior misunderstandings, medieval authors of music theory considered it a given that sensuous pleasure was the ultimate goal of music. Only by way of anachronistic readings of the sources have historians constructed an aesthetics that blended aesthetics with mathematical and theological ideas. A close reading of the sources, taking into account their cultural contexts, reveals the intentions of the authors that are at the root of the texts. Those intentions, it is argued, were not aesthetical, and any attempt to interpret them from such a perspective would be misleading. Yet careful consideration of those intentions opens the view for remarks that are truly aesthetical as well as for hints suggesting that aesthetical judgements, while self-evident, were not considered matters for written discourse but for orality.
Shape of things to come: factors affecting an ethnographic study in radiation therapy
Authors: Merchant Susan , Halkett Georgia , O’Connor Moira 
Published: March 2011

AbstractThe research process is a series of stages necessary to establish the integrity, value, and feasibility of a proposal. Part of the preparation is in understanding the process and factors that can contour a study. The aim of this paper is to outline the hidden factors that may be experienced when undertaking qualitative research. Although the participants are the main players of the study additional influences also require recognition to allow transparency of the project and the researcher’s stance. The guidance of university supervisors has the potential to influence the researcher’s perspective and the effectiveness of the study. Negotiation with clinical staff can add another dimension. Ethics committees are composed of individuals with varied expertise, bringing their points of view into the discussion and decision making, impacting further on the proposed research. It is important for medical radiations professionals who become involved in research to be aware of these factors and how they may influence a project and to acknowledge the impact of the perspectives of the researcher on the project. The significance of this paper is to provide novice researchers, an understanding of the influence, hidden factors play on the results of qualitative research with particular reference to ethnography.
A comparison of the implementation of Assertive Community Treatment in Melbourne, Australia and London, England
Authors: Harvey C. , Killaspy H. , Martino S. , White S. , Priebe S. , Wright C. , Johnson S. 
Published: March 2011

Aims.The efficacy of Assertive Community Treatment (ACT) is well established in the USA, and to a lesser extent in Australia, whereas UK studies suggest little advantage for ACT over usual care. Implementation of ACT varies and these differences may explain variability in reported efficacy. We aimed to investigate differences in ACT implementation between Melbourne, Australia and London, UK.Methods.In a cross-sectional survey, we investigated team organisation, staff and client characteristics from four Melbourne ACT teams using almost identical methods to the Pan London Assertive Outreach studies of 24 ACT teams.Results.Client characteristics, staff satisfaction and burnout were very similar. Three of four Melbourne teams made over 70% of client contacts ‘in vivo’ compared to only one-third of comparable London teams, although all teams were rated as ‘ACT-like’. Melbourne teams scored more highly on team approach. Three quarters of clients were admitted in the preceding 2 years but Melbourne clients had shorter stays.Conclusions.Differences in the implementation of ‘active components’ of home treatment models that have been associated with better client outcomes (home visiting, team approach) may explain international differences in ACT efficacy. Existing fidelity measures may not adequately weight these important elements of the model.
Evaluation of Helicoverpa and drought resistance in desi and kabuli chickpea
Authors: Yadav S. S. , Kumar J. , Yadav S. K. , Singh Shoraj , Yadav V. S. , Turner Neil C. , Redden Robert 
Published: March 2011

AbstractA chickpea collection of 1600 desi and 1400 kabuli were evaluated for yield losses arising from pod borer (Helicoverpa armigera) infestation under rainfed conditions by spraying half the plots to prevent pod borer infestation and allowing the other half to be infested. From these lines, 82 were selected for further detailed evaluation of Helicoverpa resistance and drought resistance under irrigated and rainfed conditions. The yield losses from Helicoverpa damage varied from 10 to 33% depending on the chickpea type and the growing environment. Spreading types were more susceptible to Helicoverpa damage than erect types, as were kabuli types compared to desi types. Yield losses due to Helicoverpa infestation were always greater in the irrigated than in the rainfed materials. Terminal drought reduced yields by 13–37% depending on plant type. The yields in the kabuli c“hickpea lines were more severely reduced than were the desi types, due to a greater reduction in the number of branches and pods per plant in the kabuli compared to the desi lines. It appears that the extent of pod borer damage varies between the chickpea types, and that desi types have greater drought resistance than kabuli ones. These characteristics should be informative for the population improvement of chickpea for environments in which terminal drought and Helicoverpa damage occur frequently.
The cryopreservation of embryonic axes of two wild and endangered Citrus species
Authors: Malik S. K. , Chaudhury Rekha 
Published: March 2011

AbstractThe cryopreservation of embryonic axes of two wild and endangered species, Citrusmacroptera Mont. and C. latipes Tanaka, was attempted using air desiccation–freezing, vitrification and encapsulation–dehydration. Successful cryopreservation was achieved in both the species using these three methods. However, the two species responded differently to: the rate of drying and the degree of tolerance to desiccation following air desiccation–freezing; the response to loading duration following vitrification; and to the sucrose concentration during pre-culture following encapsulation–dehydration. C. macroptera was more tolerant to desiccation and freezing than C. latipes with recovery rates of, respectively, 87% and 64%. Recovery from encapsulation–dehydration was 62% for C. macroptera and 45% for C. latipes. In both species, the vitrification protocol gave a significant improvement in recovery rates: 92% and 77% for C. macroptera and C. latipes, respectively. The air desiccation–freezing protocol being a simple and practical technique is recommended for the cryopreservation of these two species.