Design methodology for integrating multipath systems (building services)

Purpose – The purpose of this paper is to report on a geometrical integration methodology that can be used to organise some types of these systems. Most multipath delivery systems, such as Building Services (BSs), are arbitrarily distributed with no known solution to reduce the complexity in the way channels are arranged. Design/methodology/approach – Integration for optimal functionality through reduction of geometrical complexity is achieved by understanding the elements of complexity within current practices; identifying commonalities between the various components which can be used for integration; performing an axiomatic design to resolve design complications; adopting theory of inventive problem-solving for methodology and process development towards optimal functionality; and generating a mathematical solution to inform digital modelling of optimal design. The study takes into account thermophysical and electromagnetic interactions between utilities and uses novel mathematical manipulations based on designing a manifold of spherical and cylindrical geometries joined using Bezier surfaces. Findings – Once a solution was reached, computer-aided design (CAD) iterations were undertaken for channelling six BSs into a single unit. The outcome was concentric cylindrical–spherical shells superimposed with spacings of typically few millimetres to deliver/distribute the utilities. It is applied to bring together BSs into a single trunking system at minimal, yet appropriate, proximal distances, and it allows distribution of any number of services in any direction. Physical prototypes were produced and initial testing of their performance (reported elsewhere) has been encouraging. Originality/value – A design methodology for integrating arbitrary distributed paths/conduits. The approach could be incorporated into CAD tools as a design feature to facilitate integration of multipath delivery systems

3D modeling of magnetic field lines using SOHO/MDI magnetogram images

YesSolar images, along with other observational data, are very important for solar physicists and space weather researchers aiming to understand the way the Sun works and affects Earth. In this study a 3D modelling technique for visualizing solar magnetic field lines using solar images is presented. Photospheric magnetic field footpoints are detected from magnetogram images and using negative and positive magnetic footpoints, dipole pairs are associated according to their proximity. Then, 3D field line models are built using the calculated dipole coordinates, and mapped to detected pairs after coordinate transformations. Final 3D models are compared to extreme ultraviolet images and existing models and the results of visual comparisons are presented

Design approach for the integration of services in buildings

This paper describes a novel methodology to group building services (BSs) into a single trunking system at minimal proximal distances between them. The study focused on solving the geometrical complexity encountered in conventional arrangements of BSs, while taking into account thermophysical and electromagnetic interactions between services together with building regulations. The potential solution for delivery and distribution of BSs in any number of directions is an ‟onion layers„ type of design, using novel mathematical manipulations based on manifolds of spherical and cylindrical geometries joined using Bezier surfaces. Computer Aided Design iterations were undertaken for channelling six BSs into a single unit including water, air, electricity and data. It consists of concentric cylindrical-spherical shells superimposed at few millimetres gaps (channels) for which physical prototypes were produced

Michael James David Powell:29 July 1936-19 April 2015

Michael James David Powell was a British numerical analyst who was among the pioneers of computational mathematics. During a long and distinguished career, first at the Atomic Energy Research Establishment (AERE) Harwell and subsequently as the John Humphrey Plummer Professor of Applied Numerical Analysis in Cambridge, he contributed decisively towards establishing optimization theory as an effective tool of scientific enquiry, replete with highly effective methods and mathematical sophistication. He also made crucial contributions to approximation theory, in particular to the theory of spline functions and of radial basis functions. In a subject that roughly divides into practical designers of algorithms and theoreticians who seek to underpin algorithms with solid mathematical foundations, Mike Powell refused to follow this dichotomy. His achievements span the entire range from difficult and intricate convergence proofs to the design of algorithms and production of software. He was among the leaders of a subject area that is at the nexus of mathematical enquiry and applications throughout science and engineering.</jats:p

Abrasion-corrosion of cast CoCrMo in simulated hip joint environments

Metal-on-metal (MoM) hip joint replacements have been increasingly used for younger and more active patients in recent years due to their improved wear performance compared to conventional metal-on-polymer bearings. MoM bearings operate at body temperature within a corrosive joint environment and therefore are inevitably being subjected to wear and corrosion as well as the combined action of tribo-corrosion. Issues such as metal sensitivity/metallosis associated with high levels of metal ion release triggered by the wear and corrosion products remain critical concerns. During the past few decades, significant research has been conducted into understanding the wear/lubrication mechanisms within the MoM hip joints in order to improve their performance and thereby prolonging their life. However, not much attention has been given to the combined effect of wear and corrosion of such devices in the hip joint environment, in addition, the role of third body particles and the effects of proteins have not been well understood.In this work, a systemic approach is presented for the first time for the mapping of abrasion and tribo-corrosion performance of a cast CoCrMo (F75) in simulated hip joint environments. The effects of third body particles have been studied in the MoM context using 4 ?m SiC, 1 ?m and 300 nm Al2O3, as well as sub-micron BaSO4. Modified tribo-testers (micro-abrasion, nanoindenter/scratching) incorporating a novel electrochemical cell have been used to monitor the abrasion-corrosion behaviour of the alloy in situ. The effects of solution chemistry, abrasives size / concentration and presence of proteins on the wear / corrosion level, wear-corrosion mechanisms, and the depassivation/repassivation kinetics of the CoCrMo have been explored. A variety of surface and sub-surface characterization techniques have been employed to identify the microstructual wear mechanism interactions. Results show that the change of protein concentration (0, 25% and 50% bovine serum) and pH (pH 7.4 and pH 4.0) of the test solutions can significantly influence the protein adsorption behaviour, which subsequently influence the wear rates (synergy), wear mechanisms as well as the wear-induced corrosion currents of the CoCrMo. For abrasion-corrosion tests, reducing abrasive size from 4 ?m to 300 nm and/or abrasive volume concentration from 0.238 vol% to 0.006 vol% results in different abrasion-corrosion wear mechanisms (rolling or grooving abrasion) and the average wear-induced corrosion currents show a linear correlation with wear rates for 4 ?m and 1 ?m abrasives. For low volume concentration (&lt; 0.03 vol%) slurries containing bovine serum, organo-metallic conglomerates have been found within the wear scars. These conglomerates help separate the surfaces, impose less damage to the surface passive film and polish the wear scars through a chemical mechanical polishing mechanism. In addition, tribo-corrosion tests at micro-/nano- scales reveal the effects of single abrasive particle on the surface/sub-surface microstructual change. This investigation has revealed the nanoscale wear mechanisms that generate nanoscale wear debris, the mechanical mixing of the surface nanostructure with adsorbed denatured protein and also the slip/dislocation systems that are present near and on abraded surfaces that are likely to disrupt the surface passive films. The findings give a better understanding of the evolution of the sub-surface nanocrystalline structures and tribo-layers formation seen for the retrieved implants. This near surface nanostructure layer and phase transformation might offer better wear resistance through these inherent self-protecting mechanisms (i.e. increased hardness); conversely, it may become the precursors to debris ejection and enhanced ion-release into the CoCrMo joints.This work established an experimental technique that gives greater understanding of the tribocorrosion behaviour of cast CoCrMo in simulated hip joint environments. In particular, the roles of third body abrasive particles and proteins have been addressed, which are relevant to clinical applications. The material multi-scale wear mechanisms as well as the evolution of the surface / subsurface microstructures and tribo-layers have been elucidated, which provide new insights into the in vivo wear mechanisms of CoCrMo. The findings of this study may provide some important indications for improved MoM joint materials, design, manufacture and evaluation

Determination of the time-dependent thermal grooving coefficient

Changes in morphology of a polycrystalline material may occur through interface motion under the action of a driving force. An important special case that is considered in this paper is the thermal grooving that occurs when a grain boundary intersects the flat surface of a recently solidified metal slab giving rise to the formation of a thin symmetric groove. In case the transient surface diffusion is the main forming mechanism this yields a fourth-order time-dependent partial differential equation with unknown time-dependent surface diffusivity. In order to determine it, the profile of the free grooving surface at a fixed location is recorded in time. The grooving boundaries are supported by self-adjoint boundary conditions. We provide sufficient conditions on the input data for which the resulting coefficient identification problem is proved to be well-posed. Furthermore, we develop a predictor–corrector finitedifference spline method for obtaining an accurate and stable numerical solution to the nonlinear coefficient identification problem. Numerical results illustrate the performance of the inversion of both exact and noisy data

Design methodology for integrating multipath systems (building services)

Purpose – The purpose of this paper is to report on a geometrical integration methodology that can be used to organise some types of these systems. Most multipath delivery systems, such as Building Services (BSs), are arbitrarily distributed with no known solution to reduce the complexity in the way channels are arranged. Design/methodology/approach – Integration for optimal functionality through reduction of geometrical complexity is achieved by understanding the elements of complexity within current practices; identifying commonalities between the various components which can be used for integration; performing an axiomatic design to resolve design complications; adopting theory of inventive problem-solving for methodology and process development towards optimal functionality; and generating a mathematical solution to inform digital modelling of optimal design. The study takes into account thermophysical and electromagnetic interactions between utilities and uses novel mathematical manipulations based on designing a manifold of spherical and cylindrical geometries joined using Bezier surfaces. Findings – Once a solution was reached, computer-aided design (CAD) iterations were undertaken for channelling six BSs into a single unit. The outcome was concentric cylindrical–spherical shells superimposed with spacings of typically few millimetres to deliver/distribute the utilities. It is applied to bring together BSs into a single trunking system at minimal, yet appropriate, proximal distances, and it allows distribution of any number of services in any direction. Physical prototypes were produced and initial testing of their performance (reported elsewhere) has been encouraging. Originality/value – A design methodology for integrating arbitrary distributed paths/conduits. The approach could be incorporated into CAD tools as a design feature to facilitate integration of multipath delivery systems

Proceedings of the Eleventh UK Conference on Boundary Integral Methods (UKBIM 11), 10-11 July 2017, Nottingham Conference Centre, Nottingham Trent University

This book contains the abstracts and papers presented at the Eleventh UK Conference on Boundary Integral Methods (UKBIM 11), held at Nottingham Trent University in July 2017. The work presented at the conference, and published in this volume, demonstrates the wide range of work that is being carried out in the UK, as well as from further afield

Mixing in density- and viscosity-stratified flows

The lock-exchange problem is used extensively to study the flow dynamics of density-driven flows, such as gravity currents, and as a canonical problem to mixing in stratified flows. Opposite halves of a domain are filled with two fluids of different densities and held in place by a lock-gate. Upon release, the density difference drives the flow causing the fluids to slosh back and forth. In many scenarios, density stratification will also impose a viscosity stratification (e.g., if there are suspended sediments or the two fluids are distinct). However, numerical models often neglect variable viscosity. This paper characterizes the effect of both density and viscosity stratification in the lock-exchange configuration. The governing Navier-Stokes equations are solved using direct numerical simulation. Three regimes are identified in terms of the viscosity ratio μ 2 / μ 1 = (1 + γ) between the dense and less dense fluids: when γ ≪ 1, the flow dynamics are similar to the equal-viscosity case; for intermediate values (γ ∼ 1), viscosity inhibits interface-scale mixing leading to a global reduction in mixing and enhanced transfer between potential and kinetic energy. Increasing the excess viscosity ratio further (γ ≫ 1) results in significant viscous dissipation. Although many gravity or turbidity current models assume constant viscosity, our results demonstrate that viscosity stratification can only be neglected when γ ≪ 1. The initial turbidity current composition could enhance its ability to become self-sustaining or accelerating at intermediate excess viscosity ratios. Currents with initially high excess viscosity ratio may be unable to dilute and propagate long distances because of the decreased mixing rates and increased dissipation