bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental management in large‐scale building projects—learning from Hammarby Sjöstad
Authors: Johansson Rolf , Svane Örjan
Published: November 2002

In an old industrial and harbour area of Stockholm, a new city for 30 000 people will be built in the next ten years. The Hammarby Sjöstad project is unique in its size and municipal organization as well as in its ambitious environmental objectives. In a case study based on interviews and document analysis, the environmental management process of this project is researched. The City of Stockholm will follow up the compliance with set goals; our study is a qualitative one focusing on the management process. We develop concepts and models as an aid for municipal management of future construction projects. Many factors outside the formal ones are considered important. Data is structured chronologically as events and from a stakeholder perspective, including the City, the developers and the contractors. The main focus is, however, on the City's Project Management Team. Collected data is furthermore analysed with the aid of key concepts, derived from organization theory, planning and construction practice and as suggested by the data. Preliminary results indicate that the continued study of informal means of control is just as important as that of the formal ones, and that identifying key situations and tools for environmental management should be in focus for the rest of the research study. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment
Scoring corporate environmental and sustainability reports using GRI 2000, ISO 14031 and other criteria
Authors: Morhardt J. Emil , Baird Sarah , Freeman Kelly
Published: November 2002

The purpose of this paper is to evaluate the extent to which current voluntary corporate environmental reports meet the requirements of two new sets of guidelines: (i) the Global Reporting Initiative GRI 2000 sustainability reporting guidelines and (ii) the ISO 14031 environmental performance evaluation standard. We converted them to comprehensiveness scoring systems then used them along with three existing comprehensiveness scoring systems to evaluate the 1999 reports of 40 of the largest global industrial companies. Many of the reports scored highly with the existing systems, but the GRI and ISO guidelines are much more detailed and comprehensive, and resulted in much lower scores. In particular, the economic and social topics that make up 42% of the potential GRI score and the environmental condition indicators that make up 22% of the ISO 14031 score were minimally addressed in all of the companies' environmental reports. Current reporting practices of the companies whose reports we examined here are well below the standards reflected in the GRI and ISO 14031 guidelines, even when the reports scored well with existing report scoring systems. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment
Using the Australian Business Excellence Framework to achieve sustainable business excellence
Authors: Khoo Hsien Hui , Tan Kay Chuan
Published: November 2002

This article demonstrates how the Australian Business Excellence Framework can be used to support sustainable organizational development and success. The objective of the study is to identify the challenges and efforts required for an organization to be fully engaged in corporate social responsibility and sustainable business practices. A case study is used to suggest how the required efforts can be implemented. The case study involves a smelter company in the process of making a ‘shift’ from unsustainable to more sustainable operations, by implementing a new policy. The new policy will affect all aspects of the company—its people, the management of processes and information and, above all, top management's commitment in leading the transformation. An overview of the stages involved in transforming the company is preparation, transformation, implementation and sustainable business results. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Challenges in modelling stochasticity in wind
Authors: Kestens Elke , Teugels Jef L.
Published: November 2002

This article is an attempt to summarize some of the existing problems in stochastic aspects of wind. Different types of wind are listed with their specific properties. For most of them no statistical model or stochastic process has been constructed as yet. At the same time, existing problems with data are very diverse and possible improvements are proposed. For example, the quality of wind speed and wind direction data might be upgraded by a careful inclusion of measurable covariates while developing models. Other problems are dealing with extreme winds that can hardly be measured accurately. In this connection, interesting and important questions for insurance companies and for construction engineers can be tackled by applying extreme value theory. This incomplete overview hopes to encourage stochasticians to put more interest in wind problems. At the same time it is hoped that meteorologists will help them with high quality data, needed in the verification of the offered models. Copyright © 2002 John Wiley & Sons, Ltd.
Estimation of population size for additive–multiplicative models based on continuous‐time recapture experiments
Authors: Wang Yan , Yip Paul S. F.
Published: November 2002

An additive–multiplicative model and a Horvitz–Thompson‐type estimator are proposed to estimate the unknown population size in a continuous‐time recapture experiment. The proposed inference about the model parameters of the capture intensity is similar to that of Lin and Ying (1995). However, the population size in a recapture experiment is not known and a modification is needed. Simulation results are given to assess the properties of the proposed estimators and the associated inference procedures. A set of recapture data for deer mice is presented to demonstrate the performance of the estimating procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Flexible discriminant techniques for forecasting clear‐air turbulence
Authors: Tebaldi Claudia , Nychka Doug , Brown Barbara G. , Sharman Robert
Published: November 2002

Forecasting aircraft (clear‐air) turbulence is currently based on a system of observations by pilots combined with a mostly subjective evaluation of turbulence indices derived from numerical weather prediction models. We address the issue of improving the forecasting capability of the single indices by combining them in a nonparametric multidimensional regression model, and applying discriminant analysis to the resulting predicted values. Thus we enhance the predictive skills of the indices considered in isolation and provide a more robust algorithm. We adopt the paradigm of flexible discriminant analysis (FDA), and use multivariate adaptive regression splines (MARS) and neural networks (NN) in the regression stage. The data for this case study covers the period 12–15 March 1999, for the United States. Results of the analyses suggest that our statistical approach improves upon current practice to the point that it holds promise for operational forecasts. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of vertical seismic response for a large‐scale beam‐supported aqueduct
Authors: Li Yuchun , Lou Menglin , Pan Danguan
Published: November 2002

By the theories of potential flow and structural vibration, the formulae for evaluating the ‘wet’ (with water) frequencies and mode shapes of the beam‐supported aqueduct are derived through a simplified fluid‐structure interaction analysis. The time‐history formulae of structural responses to the vertical seismic excitation are obtained. Applying the response‐spectrum principle, the equivalent vertical earthquake load exerted on the beam and the corresponding effects are also derived. Several illustrative examples are conducted. The analytical results show that: (i) The ‘wet’ frequencies of the structure are lower than the corresponding ‘dry’ (without water) frequencies due to the participating water mass, but the ‘wet’ mode shapes are identical to the corresponding ‘dry’ ones. (ii) The water mass plays an important role in the vertical seismic response, which varies with the different geological sites. For the different seismic inputs, the deeper the water is, the greater are the structural responses. (iii) The vertical seismic effects on the beam are generally not too small to be neglected and should be considered in the structural designs of a beam‐supported aqueduct. Copyright © 2002 John Wiley & Sons, Ltd.
Ambient vibration studies for system identification of tall buildings
Authors: Brownjohn J. M. W.
Published: November 2002

The performance of a building under wind and seismic loads depends on stiffness and mass distribution, and may be estimated using finite element codes. Experience has, however, shown that such finite element models often fail to predict accurately the fundamental natural frequencies. Usually the frequencies will be underestimated, that is the building will turn out to be stiffer than anticipated, meaning the design would usually be conservative. On the other hand, effects like torsional eccentricity and foundation compliance may not be correctly modelled, which could be less desirable. A full understanding of linear performance under lateral loads can be obtained through experimental evaluation of the vibration modes. Traditionally only a limited range of modal analysis procedures and software has been applied to civil applications and the ‘special case’ where no input forces can be measured has been the usual situation for large civil structures. Recent developments in system identification, which is the set of procedures to build mathematical models of the dynamic structural systems based on measured data, have added significantly to the potential of ambient vibration or ‘output only’ testing. The aim of the research reported here has been to apply and evaluate the procedures on typical buildings. The procedures are briefly explained and two experimental programmes are then described; a long‐term tremor monitoring exercise on a 280m office tower and an ambient vibration survey of a smaller office block. The different forms of response data are examined to study the performance of the analysis procedures and expose benefits and limitations in their use. There is a growing interest in output‐only modal analysis procedures in civil engineering. The experience reported in this paper has shown that quick and reliable estimation of mode shapes and frequencies can be obtained, even with small amounts of data. Judgement of modal participation and damping ratios requires more detailed study yet the results are at least as convincing as existing and relatively limited frequency domain methods. Copyright © 2002 John Wiley & Sons, Ltd.
2D dynamic response of unlined and lined tunnels in poroelastic soil to harmonic body waves
Authors: Kattis S. E. , Beskos D. E. , Cheng A. H. D.
Published: November 2002

The problem of harmonic wave diffraction by tunnels in an infinite poroelastic saturated soil obeying Biot's theory is studied numerically under conditions of plane strain and the effect of poroelasticity on the response is assessed through some parametric studies. The method is based on the theory of Mei and Foda, which considers the total field to be approximated by the superposition of an elastodynamic problem with modified elastic constants and mass density for the whole domain and a diffusion problem for the pore fluid pressure confined to a boundary layer at the free boundaries. Both problems are solved numerically by the boundary element method in the frequency domain. Results dealing with the response of a circular tunnel with and without an elastic concrete liner in an infinite poroelastic medium to incident harmonic P and SV plane waves are provided and compared against analytical ones as well as to those corresponding to linear elastic soil behaviour. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of the spatial variability of channel morphology
Authors: Moody John A. , Troutman Brent M.
Published: November 2002

The spatial variability of two fundamental morphological variables is investigated for rivers having a wide range of discharge (five orders of magnitude). The variables, water‐surface width and average depth, were measured at 58 to 888 equally spaced cross‐sections in channel links (river reaches between major tributaries). These measurements provide data to characterize the two‐dimensional structure of a channel link which is the fundamental unit of a channel network.

The morphological variables have nearly log‐normal probability distributions. A general relation was determined which relates the means of the log‐transformed variables to the logarithm of discharge similar to previously published downstream hydraulic geometry relations. The spatial variability of the variables is described by two properties: (1) the coefficient of variation which was nearly constant (0·13–0·42) over a wide range of discharge; and (2) the integral length scale in the downstream direction which was approximately equal to one to two mean channel widths. The joint probability distribution of the morphological variables in the downstream direction was modelled as a first‐order, bivariate autoregressive process. This model accounted for up to 76 per cent of the total variance. The two‐dimensional morphological variables can be scaled such that the channel width–depth process is independent of discharge. The scaling properties will be valuable to modellers of both basin and channel dynamics. Published in 2002 John Wiley & Sons, Ltd.
Impact of road building on gully erosion risk: a case study from the Northern Ethiopian Highlands
Authors: Nyssen Jan , Poesen Jean , Moeyersons Jan , Luyten Edith , Veyret‐Picot Maude , Deckers Jozef , Haile Mitiku , Govers Gerard
Published: November 2002

Although obvious in the field, the impact of road building on hydrology and gullying in Ethiopia has rarely been analysed. This study investigates how road building in the Ethiopian Highlands affects the gully erosion risk. The road between Makalle and Adwa in the highlands of Tigray (northern Ethiopia), built in 1993–1994, caused gullying at most of the culverts and other road drains. While damage by runoff to the road itself remains limited, off‐site effects are very important. Since the building of the road, nine new gullies were created immediately downslope of the studied road segment (6·5 km long) and seven other gullies at a distance between 100 and 500 m more downslope. The road induces a concentration of surface runoff, a diversion of concentrated runoff to other catchments, and an increase in catchment size, which are the main causes for gully development after road building. Topographic thresholds for gully formation are determined in terms of slope gradient of the soil surface at the gully head and catchment area. The influence of road building on both the variation of these thresholds and the modification of the drainage pattern is analysed. The slope gradient of the soil surface at the gully heads which were induced by the road varies between 0·06 and 0·42 m m−1 (average 0·15 m m−1), whereas gully heads without influence of the road have slope gradients between 0·09 and 0·52 m m−1 (average 0·25 m m−1). Road building disturbed the equilibrium in the study area but the lowering of topographic threshold values for gullying is not statistically significant. Increased gully erosion after road building has caused the loss of fertile soil and crop yield, a decrease of land holding size, and the creation of obstacles for tillage operations. Hence roads should be designed in a way that keeps runoff interception, concentration and deviation minimal. Techniques must be used to spread concentrated runoff in space and time and to increase its infiltration instead of directing it straight onto unprotected slopes. Copyright © 2002 John Wiley & Sons, Ltd.
An integrated hydrological model for rain‐induced landslide prediction
Authors: Wilkinson P. L. , Anderson M. G. , Lloyd D. M.
Published: November 2002

This paper describes an extension to the Combined Hydrology And Stability Model (CHASM) to fully include the effects of vegetation and slope plan topography on slope stability. The resultant physically based numerical model is designed to be applied to site‐specific slopes in which a detailed assessment of unsaturated and saturated hydrology is required in relation to vegetation, topography and slope stability. Applications are made to the Hawke's Bay region in New Zealand where shallow‐seated instability is strongly associated with spatial and temporal trends in vegetation cover types, and the Mid‐Levels region in Hong Kong, an area subject to a variety of landslide mechanisms, some of which may be subject to strong topographic control. An improved understanding of process mechanism, afforded by the model, is critical for reliable and appropriate design of slope stabilization and remedial measures. Copyright © 2002 John Wiley & Sons, Ltd.
On the shape and migration speed of a proto‐dune
Authors: Momiji Hiroshi , Nishimori Hiraku , Bishop Steven R.
Published: November 2002

The shape and migration speed of a proto‐dune are mathematically discussed. The migration speed of a low dune is shown to be inversely proportional to its wind‐directional length. Proto‐dunes, whose wind‐directional lengths are about 10 m, are expected to migrate at finite speeds. Copyright © 2002 John Wiley & Sons, Ltd.
The use of small‐format and low‐altitude aerial photos for the realization of high‐resolution DEMs in mountainous areas: application to the Super‐Sauze earthflow (Alpes‐de‐Haute‐Provence, France)
Authors: Henry J.‐B. , Malet J.‐P. , Maquaire O. , Grussenmeyer P.
Published: November 2002

Geomorphologists have to make choices and compromises, as acquisition techniques of geometrical information are numerous, depending on the specific complexity of the targeted three‐dimensional objects and the requirements of the end user. This article presents the methodology and the results over a well known and documented site. This ready‐to‐use, low‐altitude, aerial photo methodology reveals itself to be a satisfying compromise between cost, accuracy and difficulty of implementation. The selected equipment package is light enough to enable a quick reaction to unexpected events and the tools and methods are competitive with field acquisition techniques. An evaluation has demonstrated a sub‐metric accuracy for the final result. Copyright © 2002 John Wiley & Sons, Ltd.
The use of a landscape simulator in the validation of the SIBERIA landscape evolution model: transient landforms
Authors: Hancock G. R. , Willgoose G. R.
Published: November 2002

SIBERIA is a physically based model for the geomorphic evolution of landforms. It is essential that the SIBERIA model be tested or validated against controlled landform development. Previous studies have demonstrated that SIBERIA is able to simulate declining equilibrium landforms and in this paper we examine SIBERIA's ability to simulate landforms as they evolve to their declining equilibrium form. These landscapes are termed transient landforms. Landscapes generated by SIBERIA were compared to those produced by a physical model (experimental model landforms) at stages of evolution. Comparison of the experimental landscapes with the simulated landscapes using total mass, hypsometric curve, width function, cumulative area distribution and area–slope demonstrate that SIBERIA can simulate the experimental model landscape during development (i.e. transient landscapes). Copyright © 2002 John Wiley & Sons, Ltd.
Extension of a combined analytical/numerical initial value problem solver for unsteady periodic flow
Authors: De Chant Lawrence J. , Seidel Jonathan A. , Kline Teresa R.
Published: November 2002

Here we describe analytical and numerical modifications that extend the Differential Reduced Ejector/ mixer Analysis (DREA), a combined analytical/numerical, multiple species ejector/mixing code developed for preliminary design applications, to apply to periodic unsteady flow. An unsteady periodic flow modelling capability opens a range of pertinent simulation problems including pulse detonation engines (PDE), internal combustion engine ICE applications, mixing enhancement and more fundamental fluid dynamic unsteadiness, e.g. fan instability/vortex shedding problems. Although mapping between steady and periodic forms for a scalar equation is a classical problem in applied mathematics, we will show that extension to systems of equations and, moreover, problems with complex initial conditions are more challenging. Additionally, the inherent large gradient initial condition singularities that are characteristic of mixing flows and that have greatly influenced the DREA code formulation, place considerable limitations on the use of numerical solution methods. Fortunately, using the combined analytical–numerical form of the DREA formulation, a successful formulation is developed and described. Comparison of this method with experimental measurements for jet flows with excitation shows reasonable agreement with the simulation. Other flow fields are presented to demonstrate the capabilities of the model. As such, we demonstrate that unsteady periodic effects can be included within the simple, efficient, coarse grid DREA implementation that has been the original intent of the DREA development effort, namely, to provide a viable tool where more complex and expensive models are inappropriate. Copyright © 2002 John Wiley & Sons, Ltd.
A Petrov–Galerkin method for flows in cavities: enclosure of aspect ratio 8
Authors: Suslov Sergey A. , Paolucci Samuel
Published: November 2002

A Petrov–Galerkin method for computations of fully enclosed flows is developed. It makes use of divergence‐free basis functions which also satisfy the boundary conditions for the velocity field. This allows the elimination of the unknown pressure. The computational procedure reduces to the solution of a system of non‐linear first‐order ordinary differential equations for the spectral expansion coefficients. We illustrate the effectiveness and accuracy of the method by solving the problem of the two‐dimensional thermoconvective flow in a rectangular cavity of aspect ratio 8 at Rayleigh number 3.4×105. Copyright © 2002 John Wiley & Sons, Ltd.
Unsteady natural convection in tall side‐heated cavities
Authors: Armfield S. , Schultz A.
Published: November 2002

A finite‐volume scheme is used to simulate super‐critical natural convection flow in a side‐heated cavity with height/width aspect ratio of eight. The flow is unsteady with travelling waves circulating around the cavity in the flow direction. Results on a range of grids with QUICK and central difference advection discretizations show that a very fine grid is required to ensure a converged solution is obtained. A linear parallel stability analysis has been carried out and it is shown that the basic wave structure of the flow is well predicted. Copyright © 2002 John Wiley & Sons, Ltd.
An operator‐splitting finite‐element approach to the 8:1 thermal‐cavity problem
Authors: Davis D. , Bänsch E.
Published: November 2002

This article describes the methodology for, and results obtained from, our contribution to the thermal‐cavity benchmark test. Our solutions were obtained on graded rectangular grids for two different time‐discretization schemes by applying a finite‐element procedure to the model equations, and a combination of conjugate‐gradient and GMRES solvers to the resulting matrix systems. Copyright © 2002 John Wiley & Sons, Ltd.
Fourth‐order finite difference simulation of a differentially heated cavity
Authors: Johnston Hans , Krasny Robert
Published: November 2002

We present benchmark simulations for the 8: 1 differentially heated cavity problem, the focus of a special session at the first MIT conference on Computational Fluid and Solid Mechanics in June 2001. The numerical scheme is a fourth‐order finite difference method based on the vorticity‐stream function formulation of the Boussinesq equations. The momentum equation is discretized by a compact scheme with the no‐slip boundary condition enforced using a local vorticity boundary condition. Long‐stencil discretizations are used for the temperature transport equation with one‐sided extrapolation applied near the boundary. The time stepping scheme for both equations is classical fourth‐order Runge–Kutta. The main step is the solution of two discrete Poisson‐like equations at each Runge–Kutta time stage, which are solved using FFT‐based methods. Copyright © 2002 John Wiley & Sons, Ltd.
Numerical prediction of natural convection in a tall enclosure
Authors: Christopher David M.
Published: November 2002

The equations for natural convection flow in a tall cavity were solved for a super‐critical Rayleigh number for which oscillations occur in the flow field and various solutions are possible. The objective was to compare various solution methods for this complex flow situation. The equations were solved using the finite element method with the Galerkin form of the method of weighted residuals with various time integration methods, time steps and grid spacings. The Euler time integration method is unsuitable for this problem because of its excessive dissipation. Fine grid distributions and small time steps were needed to predict accurate values of the average temperatures and velocities in the cavity, with even finer elements and time steps needed to accurately predict the amplitudes of the oscillations. An initially uniform temperature distribution lead to a uniformly oscillating skew‐symmetric flow field. An initially random temperature field lead to a symmetry‐breaking flow field that eventually reached the skew‐symmetric flow field after a long time. Copyright © 2002 John Wiley & Sons, Ltd.
A numerical study of a natural convection flow in a cavity
Authors: Guo Yanhu , Bathe Klaus‐Jürgen
Published: November 2002

The solution to a benchmark problem of a differentially heated cavity flow with Ra=3.4×105 and Pr=0.71 was solicited for presentation at a special session entitled ‘Computational Predictability of Natural Convection Flows in Enclosures’ which was held at the First MIT Conference on Computational Fluid and Solid Mechanics. The objective of this paper is to present the results obtained using the ADINA System.

The 9‐node quadrilateral element in ADINA was used with various meshes. Periodic solutions with a period of 3.42–3.43 were obtained. Compared with the average values of the solution variables and the periods, the calculated amplitudes of the periodic solutions were found to be more sensitive to the spatial and temporal discretizations used. The flow patterns, such as boundary layers, vortices, etc. were also studied using a fine 40×120 element mesh. Vortices and their evolutions were revealed inside the periodic flow field. Copyright © 2002 John Wiley & Sons, Ltd.
Computational predictability of time‐dependent natural convection flows in enclosures (including a benchmark solution)
Authors: Christon Mark A. , Gresho Philip M. , Sutton Steven B.
Published: November 2002

This paper summarizes the results from a special session dedicated to understanding the fluid dynamics of the 8:1 thermally driven cavity which was held at the First MIT Conference on Computational Fluid and Solid Dynamics in June, 2001. The primary objectives for the special session were to: (1) determine the most accurate estimate of the critical Rayleigh number above which the flow is unsteady, (2) identify the correct, i.e. best time‐dependent benchmark solution for the 8: 1 differentially heated cavity at particular values of the Rayleigh and Prandtl numbers, and (3) identify those methods that can reliably provide these results. Copyright © 2002 John Wiley & Sons, Ltd.
From steady to chaotic solutions in a differentially heated cavity of aspect ratio 8
Authors: Bruneau Charles‐Henri , Saad Mazen
Published: November 2002

A splitting method is used for the temperature and the velocity–pressure unknowns to solve the time‐dependent thermal convection problem in an 8:1 enclosure (International Journal for Numerical Methods, this issue). High performance is obtained by means of incomplete Cholesky conjugate gradient for the temperature equation on one hand and a multigrid procedure for Navier–Stokes equations on the other hand. The approximation is achieved by second‐ and third‐order finite differences on staggered grids. The stability of the steady solution is analysed by the computation of the first Lyapunov exponent. The periodic flow at Ra=3.4×105 is widely discussed and some investigations have been done for some higher Rayleigh numbers. Copyright © 2002 John Wiley & Sons, Ltd.
Fully coupled and operator‐splitting approaches for natural convection flows in enclosures
Authors: Turek S. , Schmachtel R.
Published: November 2002

We present two different numerical approaches for the simulation of incompressible flow with heat transfer which is described via the Boussinesq model. Exemplarily, we describe a fully coupled approach, which allows both non‐steady and steady simulations, while the decoupled approach is based on operator‐splitting techniques as typical for fully non‐steady incompressible problems. We discuss the numerical and computational characteristics and show results for the MIT2001 benchmark. All results are based on the Open Source CFD tool FEATFLOW (see www.featflow.de). Copyright © 2002 John Wiley & Sons, Ltd.
Numerical investigation of the first instabilities in the differentially heated 8:1 cavity
Authors: Auteri F. , Parolini N.
Published: November 2002

We present a new Galerkin–Legendre spectral projection solver for the simulation of natural convection in a differentially heated cavity. The projection method is applied to the study of the first non‐stationary instabilities of the flow in a 8:1 cavity. Statistics of the periodic solution are reported for a Rayleigh number of 3.4×105. Moreover, we investigate the location and properties of the first Hopf bifurcation and of the three successive bifurcations. The results confirm the previous finding in the range of Rayleigh numbers investigated that the flow instabilities originate in the boundary layer on the vertical walls. A peculiar phenomenon of symmetry breaking and symmetry restoring is observed portraying the first steps of the transition to chaos for this flow. Copyright © 2002 John Wiley & Sons, Ltd.
An extended Chebyshev pseudo‐spectral benchmark for the 8:1 differentially heated cavity
Authors: Xin Shihe , Quéré Patrick Le
Published: November 2002

Our contribution to the benchmark is multifold. In addition to providing accurate unsteady simulations at the required Ra value of 3.4 × 105, we determine accurately the three first critical bifurcation points, investigate the supercritical regime, and study the differences between time‐averaged solutions and the corresponding base solution at Ra = 4× 105. We thereby establish the existence of, at least, 4 different branches of solutions and of 3 multiple unsteady periodic solutions for a Rayleigh value of 4 × 105. First appearance of quasi‐periodic flow is found at Ra about 5.0 × 105 and first appearance of chaotic solutions is found for 5.5 × 105 approximately. We investigate the differences between time‐averaged solutions and the corresponding base flow solution at Ra = 4 × 105. It is found that they exhibit symmetric feature and similar spatial distribution and that their amplitudes are proportional to the squared amplitude of periodic solutions.

All these computations are carried out using 2D Chebyshev spatial approximations with spatial resolution up to 48 × 180. For the unsteady computations, a second order time stepping scheme is used, the incompressibility condition being strictly enforced through the use of an influence matrix technique, while for the accurate determination of the critical points, an original algorithm based on a combination of Newton, continuation and Arnoldi Krylov type methods was developed.

Furthermore we investigate the stability of the 2D benchmark solution with respect to 3D periodic disturbances by using a spectral (Chebyshev and Fourier) time‐stepping (projection) code. In the 8:1 cavity we did not find any 3D instability before the onset of time dependence of 2D flows nor at the mandatory Ra of 3.4 × 105. 3D instabilities were observed for Ra about 4× 105 corresponding to a typical wavelength of two times the cavity width. Copyright © 2002 John Wiley & Sons, Ltd.
LS‐DYNA and the 8:1 differentially heated cavity
Authors: Christon Mark A.
Published: November 2002

This paper presents results computed using LS‐DYNA's new incompressible flow solver for a differentially heated cavity with an 8:1 aspect ratio at a slightly super‐critical Rayleigh number. Three Galerkin‐based solution methods are applied to the 8:1 thermal cavity on a sequence of four grids. The solution methods include an explicit time‐integration algorithm and two second‐order projection methods—one semi‐implicit and the other fully implicit. A series of ad hoc modifications to the basic Galerkin finite element method are shown to result in degraded solution quality with the most serious effects introduced by row‐sum lumping the mass matrix. The inferior accuracy of a lumped mass matrix relative to a consistent mass matrix is demonstrated with the explicit algorithm which fails to obtain a transient solution on the coarsest grid and exhibits a general trend to under‐predict oscillation amplitudes. The best results are obtained with semi‐implicit and fully implicit second‐order projection methods where the fully implicit method is used in conjunction with a ‘smart’ time integrator. Copyright © 2002 John Wiley & Sons, Ltd.
Weighted average flux method and flux limiters for the numerical simulation of shock waves in rigid porous media
Authors: Torrens R. , Wrobel L. C.
Published: November 2002

The one‐dimensional flow field generated by the passage of a shock wave in a rigid, thermoelastic porous foam has been simulated using a two‐phase mathematical model. The work presented here makes use of the weighted average flux method to solve the system of six equations that govern the problem. Spurious oscillations are eliminated through the application of total variation diminishing limiting methods. Four different limiters were tested: van Leer, SuperA, MinA and van Albada. Numerical tests were carried out to verify the performance of each flux limiter in terms of accuracy. The results were compared to analytical and previously obtained data to assess the performance of the mathematical model. Excellent agreement was obtained. Copyright © 2002 John Wiley & Sons, Ltd.
A Mach‐uniform unstructured staggered grid method
Authors: Wenneker I. , Segal A. , Wesseling P.
Published: November 2002

A novel Mach‐uniform method to compute flows using unstructured staggered grids is discussed. The Mach‐uniform method is a generalization of the pressure‐correction approach for incompressible flows, and is valid for Mach numbers ranging from 0 (incompressible) to > 1 (supersonic). The primary variables (ρu,p and ρ) are updated sequentially. The grid consists of triangles. A staggered positioning of the variables is employed: the scalar variables are located at the centroids of the triangles, whereas the normal momentum components are positioned at the midpoints of the faces of the triangles. Discretization of the two‐dimensional flow equations on unstructured staggered grids is discussed. For the cell face fluxes there is a choice between first‐order upwind and central approximation. Flows around the NACA 0012 airfoil with freestream Mach numbers ranging from 0 to 1.2 are computed to demonstrate the Mach‐uniform accuracy and efficiency of the proposed method. Copyright © 2002 John Wiley & Sons, Ltd.
Extending the temporal and spatial limits of gentrification: a research agenda for population geographers
Authors: Smith Darren P.
Published: November 2002

How processes of gentrification unfold, at what rate, and with what effects, can all differ substantially in different places. Although pre‐existing theories have sought to encapsulate this diversity, the temporal and spatial limits of gentrification processes have yet to be fully explored. This paper postulates that population geographers have a role to play here. Firstly, researchers are urged to study gentrification within a broader temporal perspective, and to unravel connections between migration dynamics and population transitions over the course of the process. Secondly, it is contended that processes and effects of gentrification should be examined within wider spatial frameworks, whereby migration flows of relatively affluent households are evaluated within the context of (re)urbanisation, suburbanisation and counterurbanisation. This may pose important questions about the understandings of demographic links between gentrification and in‐migrants at particular stages of their life‐course. It is argued that this research agenda will require the adoption of more inclusive definitions of gentrification, embracing wider spatial and temporal criteria. Copyright © 2002 John Wiley & Sons, Ltd.
A geographical analysis of spatial differentials in mobility and self‐care limitations among older Americans
Authors: Lin Ge , Zimmer Zachary
Published: November 2002

In this article we examine regional variations in functional limitations of older Americans. We consider models for ‘life‐long residents’ or those who currently live in their region of birth, and ‘secondary residents’ or those who live in a different region. Sizeable differences in limitations exist, with a higher rate in southern regions. Using a multinomial logit model, we further assess the geographical disparities in functional status while controlling for socioeconomic status (SES) and other characteristics. We conclude that the regional differentials are persistent. Those who have moved away from the south carry a burden of functional limitation with them wherever they go. Simulations based on estimated models suggest that improving individual SES can substantially increase the disability‐free life span, but it cannot completely negate geographical influences. Copyright © 2002 John Wiley & Sons, Ltd.
Labour‐market participation of Asian Indian immigrant women in the greater Kansas City Metropolitan Area, USA
Authors: De Dunn Sujata , Paul Bimal Kanti
Published: November 2002

Immigrants are changing the composition of the American population at the end of the twentieth and into this century, just as they have done for many decades. The amended Immigration and Naturalization Act of 1965 resulted in a steady flow of professional Asian Indians to the United States. While receiving indirect attention in several studies, relatively little is known about the labour‐market participation of Asian Indian immigrant women. This research aims to determine the economic and non‐economic factors that influence the participation of Asian Indian immigrant women in the labour market of the Greater Kansas City Metropolitan Area. On the basis of 160 responses from a questionnaire survey, this research found that annual income, years in current job, occupation type, and the nature of investment in India were the pertinent economic factors, while non‐economic factors range from age, urban residential background, education, number of years in the US, the decision to work, and some perceptions on work, homemaking and household income contribution. Findings from this study are discussed in the context of existing theories on international migration, particularly those dealing with the labour‐force participation of immigrants. Copyright © 2002 John Wiley & Sons, Ltd.
Mothers' insightfulness regarding their children's internal worlds: The capacity underlying secure child–mother relationships
Authors: Oppenheim David , Koren‐Karie Nina
Published: November 2002

This article introduces a new method to assess mothers' insightfulness regarding their children's inner world. Maternal insightfulness involves the capacity to see things from the child's point of view, and is based on insight into the child's motives, a complex view of the child, and openness to new information about the child. Insightfulness is seen as the capacity underlying positive parenting and providing the context for secure child–parent attachment. In the assessment of insightfulness mothers view video segments of their interactions with their children and are subsequently interviewed regarding their children's and their own thoughts and feelings during the segments. This article describes how the maternal interviews are coded and provides vignettes of both insightful and noninsightful mothers. Empirical findings supporting the validity of the insightfulness assessment are reviewed, and the implications for children's development are discussed. ©2002 Michigan Association for Infant Mental Health.
Depressed mothers' newborns show longer habituation and fail to show face/voice preference
Authors: Hernandez‐Reif Maria , Field Tiffany , Diego Miguel , Largie Shay
Published: November 2002

Twenty neonates of depressed and nondepressed mothers failed to show an initial visual preference for their mother's versus a female stranger's face/voice. Subsequently, infants were habituated to their mother's face and voice. Infants of depressed mothers required 1/3 more trials and almost twice as long to habituate. A posthabituation test with their mother and a different female stranger revealed a preference for the stranger's face for 9 out of the 10 newborns of the nondepressed mothers. Again, the infants of depressed mothers displayed no visual preference. These findings reveal differences in depressed mothers newborns' speed of habituation and face/voice preferences. ©2002 Michigan Association for Infant Mental Health.
The European Early Promotion Project: A new primary health care service to promote children's mental health
Authors: Puura Kaija , Davis Hilton , Papadopoulou Kalliroi , Tsiantis John , Ispanovic‐Radojkovic Veronika , Rudic Nenad , Tamminen Tuula , Turunen Merja‐Maaria , Dragonas Thalia , Paradisiotou Anna , Vizakou Semeli , Roberts Rosemarie , Cox Antony , Day Crispin
Published: November 2002

The number of children in Europe with significant psychologic and social problems is large and increasing. This article describes an innovative crosscultural method of working with families to promote the psychosocial well being of children and prevent the development of psychologic and social problems. A study designed to evaluate the effects of the service is also presented. Primary health care workers in five European countries have been trained to conduct promotional interviews with all prospective mothers in their area one month before and one month after birth. They have also been taught to work with mothers identified as in need of support as a parent by using a specific counselling model to try to prevent the onset of child mental health difficulties. Effects of the intervention on children's psychologic development and family adaptation are being evaluated at two years in comparison with matched groups not receiving the intervention. ©2002 Michigan Association for Infant Mental Health.
Ca2+/calmodulin‐dependent protein kinase II‐dependent long‐term potentiation in the rat suprachiasmatic nucleus and its inhibition by melatonin
Authors: Fukunaga Kohji , Horikawa Kazumasa , Shibata Shigenobu , Takeuchi Yusuke , Miyamoto Eishichi
Published: November 2002

We recently reported that Ca2+/calmodulin‐dependent protein (CaM) kinase II is involved in light‐induced phase delays and Per gene induction in the suprachiasmatic nucleus (SCN). To clarify the activation mechanisms of CaM kinase II by glutamate receptor stimulation in the SCN, we documented CaM kinase II activation following induction of long‐term potentiation (LTP) in the rat SCN. High‐frequency stimulation (100 Hz, 1 sec) applied to the optic nerve resulted in LTP of a postsynaptic field potential in the rat SCN. Unlike LTP in the hippocampal CA1 region, LTP onset in the SCN was slow and partly dependent on N‐methyl‐D‐aspartate receptor activation. LTP induction in the SCN was completely inhibited by treatment with a nitric oxide synthase inhibitor or with a specific CaM kinase II inhibitor. Immunoblotting analysis using phosphospecific antibodies against autophosphorylated CaM kinase II revealed that LTP induction was accompanied by an increase in autophosphorylation. After high‐frequency stimulation, we could visualize activation of CaM kinase II in vasoactive intestinal polypeptide‐positive neurons in the SCN by immunohistochemistry. Treatment with cyclosporin A, a calcineurin inhibitor, potentiated LTP induction in the rat SCN. Interestingly, treatment with melatonin totally prevented LTP induction, without changes in basal synaptic transmission. Analyses of phosphorylation of CaM kinase II, mitogen‐activated protein kinase, and cAMP‐responsive element binding protein revealed that stimulatory and inhibitory effects on CaM kinase II autophosphorylation underlie the effects of cyclosporin A and melatonin, respectively. These results suggest that CaM kinase II plays critical roles in LTP induction in the SCN and that melatonin has inhibitory effects on synaptic plasticity through CaM kinase II. © 2002 Wiley‐Liss, Inc.
Neurotensin enhances glutamate excitotoxicity in mesencephalic neurons in primary culture
Authors: Antonelli T. , Tomasini M.C. , Finetti S. , Giardino L. , Calzà L. , Fuxe K. , Soubriè P. , Tanganelli S. , Ferraro L.
Published: November 2002

The tridecapeptide neurotensin has been demonstrated to increase glutamate release in discrete rat brain regions, leading to the hypothesis of a possible involvement of the peptide in neurodegenerative pathologies. The role of neurotensin in modulating glutamate excitotoxicity and the possible neuroprotective action of the neurotensin receptor antagonist SR48692 were investigated in primary cultures of mesencephalic neurons by measuring [3H]dopamine uptake and tyrosine hydroxylase immunocytochemistry 24 hr after glutamate treatment. The exposure to glutamate (30 and 100 μM, 10 min) decreased [3H]dopamine uptake into mesencephalic neurons. Neurotensin (10 and 100 nM), added before glutamate (30 μM) exposure, significantly enhanced the glutamate‐induced reduction of [3H]dopamine uptake. In addition, the peptide (10 nM) also significantly enhanced the effect of 100 μM glutamate. The effects of neurotensin were counteracted by the neurotensin receptor antagonist SR48692 (100 nM) and by the protein kinase C inhibitor calphostin C. The exposure to 100 μM, but not 30 μM, glutamate significantly reduced the number of tyrosine hydroxylase‐immunoreactive cells, and neurotensin (10 nM) significantly enhanced this effect. SR48692 (100 nM) prevented the neurotensin‐induced action. These findings support the view of a possible pathophysiological role of neurotensin in mesencephalic dopamine neuronal function. Furthermore, selective neurotensin antagonists in combination with conventional drug treatments could provide a novel therapeutic approach for the treatment of neurodegenerative disorders, such as Parkinson's disease. © 2002 Wiley‐Liss, Inc.