Integrated engineering environments for large complex products

An introduction is given to the Engineering Design Centre at the University of Newcastle upon Tyne, along with a brief explanation of the main focus towards large made-to-order products. Three key areas of research at the Centre, which have evolved as a result of collaboration with industrial partners from various sectors of industry, are identified as (1) decision support and optimisation, (2) design for lifecycle, and (3) design integration and co-ordination. A summary of the unique features of large made-to-order products is then presented, which includes the need for integration and co-ordination technologies. Thus, an overview of the existing integration and co-ordination technologies is presented followed by a brief explanation of research in these areas at the Engineering Design Centre. A more detailed description is then presented regarding the co-ordination aspect of research being conducted at the Engineering Design Centre, in collaboration with the CAD Centre at the University of Strathclyde. Concurrent Engineering is acknowledged as a strategy for improving the design process, however design coordination is viewed as a principal requirement for its successful implementation. That is, design co-ordination is proposed as being the key to a mechanism that is able to maximise and realise any potential opportunity of concurrency. Thus, an agentoriented approach to co-ordination is presented, which incorporates various types of agents responsible for managing their respective activities. The co-ordinated approach, which is implemented within the Design Co-ordination System, includes features such as resource management and monitoring, dynamic scheduling, activity direction, task enactment, and information management. An application of the Design Co-ordination System, in conjunction with a robust concept exploration tool, shows that the computational design analysis involved in evaluating many design concepts can be performed more efficiently through a co-ordinated approach

Effect of dialysate temperature on central hemodynamics and urea kinetics

Effect of dialysate temperature on central hemodynamics and urea kinetics. Use of cool dialysate is associated with increased intradialytic blood pressure, but the hemodynamic mechanism is unknown. Whether changes in dialysate temperature affect muscle blood flow, which may the alter the degree of urea compartmentalization, also is unknown. We measured hemodynamics and blood and dialysate-side urea kinetic indices in nine hemodialysis patients during two cool (35.0°C) versus two warm (37.5°C) dialysate treatments. The % change in mean arterial pressure was different when using the cool (+6.5 ± 9.7 mm Hg) versus the warm (-13.4 ± 3.6) dialysate (P < 0.01), despite comparable amounts of fluid removal. Percent changes in cardiac output were similar with the two dialysates, and thus the blood pressure effect was due primarily to changes in total peripheral resistance (%ΔTPR, cool +26 ± 13.6, warm +8.6 ± 14.5; P < 0.02). During cool dialysate use tympanic membrane temperature changed by -0.51 ± 0.23°C, whereas body temperature increased by 0.52 ± 0.14°C during use of warm dialysate. Measured urea recovery normalized to the predialysis urea nitrogen concentration was similar with the two treatments: cool 31.3 ± 0.039 liter-1; warm 29.7 ± 0.021; P = NS. In a second study, post-dialysis urea rebound values from 15 seconds to 30 minutes, expressed as the percent of the post-dialysis SUN, were similar after the two treatments: cool 11.79 ± 1.4; warm 12.21 ± 2.27, P = NS. The results suggest that increased blood pressure associated with use of cool dialysate is due to an increased TPR, and that this alteration in hemodynamics has no clinically important effects on either the amount of urea removal or the extent of post-dialysis urea rebound

Quantitative analysis of the residual stress and dislocation density distributions around indentations in alumina and zirconia toughened alumina (ZTA) ceramics

Alumina, 10% and 20% ZTA with 1.5mol% yttria stabiliser were subjected to Vickers indentation testing with loads from 1 to 20kg. Cr fluorescence and Raman spectroscopy were applied to the indent centre and around the indentation in order to investigate the origin of the signal, the effect of indentation loads and zirconia phase transformation on the residual stress and plastic deformation in the plastic zone. The results suggested that with very strong laser scattering, the depth resolution of ZTA materials was very poor, which lead to a very significant amount of the signal being collected from the subsurface regions below the plastic zone. It was also found that zirconia phase transformation reduced the compressive residual stress in the alumina matrix within the plastic zone, except at the indentation centre, due to the tensile residual microstress generated by the zirconia phase transformation. In addition, the dislocation density on the indent surface of the ZTA samples was significantly reduced due to the restriction of crack propagation and energy absorption during the phase transformation process. At the indent centre, the zirconia phase transformation was suppressed by the high compressive stress, therefore, no significant difference between alumina and ZTA in terms of their residual stress and dislocation density were observed. Using TEM observation, it was found that the plastic zone microstructure of pure alumina is different from that of ZTA, which is consistent with the Cr fluorescence results

Supporting 'design for reuse' with modular design

Engineering design reuse refers to the utilization of any knowledge gained from the design activity to support future design. As such, engineering design reuse approaches are concerned with the support, exploration, and enhancement of design knowledge prior, during, and after a design activity. Modular design is a product structuring principle whereby products are developed with distinct modules for rapid product development, efficient upgrades, and possible reuse (of the physical modules). The benefits of modular design center on a greater capacity for structuring component parts to better manage the relation between market requirements and the designed product. This study explores the capabilities of modular design principles to provide improved support for the engineering design reuse concept. The correlations between modular design and 'reuse' are highlighted, with the aim of identifying its potential to aid the little-supported process of design for reuse. In fulfilment of this objective the authors not only identify the requirements of design for reuse, but also propose how modular design principles can be extended to support design for reuse

Development of enteric coated sustained release minitablets containing mesalamine

The aim of this study was to develop and evaluate a multiparticulate modified release system, composed of minitablets with a sustained release matrix system coated with a pH-dependent release polymer, using mesalamine as a model drug. Polyox® WSR 1105 was the polymer used in the matrix system and Eudragit® L30D55 was used as a pH-dependent polymer. The minitablets (with 20%, 30% or 40% Polyox® concentration) were prepared by dry granulation, which led to good quality minitablets. The developed minitablets were coated in a fluidized bed at 8% of the coating level. Dissolution studies were performed in media that simulated the gastrointestinal tract (pH 1.4, 6.0 and 7.2) and showed that formulations with higher Polyox® concentrations were capable of retaining the drug release in pH 1.4. All formulations prolonged the drug release and presented zero-order kinetic behaviour. The Korsmeyer-Peppas model demonstrated that formulations with 20% or 30% of polymer exhibited anomalous transport behaviour, whilst the 40% sample exhibited super case II model transportation. Dissolution efficiency showed that only the formulations containing 20% and 40% polymer could be considered statistically different

Age at first birth in women is genetically associated with increased risk of schizophrenia

Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

Residual stress distribution in a functionally graded alumina-silicon carbide material

Functionally graded ceramic structures have a range of potential applications as they enable the exploitation of two ceramic materials with very different properties, such as coefficient of thermal expansion. We report the microstructural investigation of a novel functionally graded structure for alumina and silicon carbide with systematically varied composition. Stresses in the structure have been modelled analytically and by finite element modelling, and are consistent with fluorescence microscopy measurements of residual stress in the structure

Ultra-fast and energy-efficient sintering of ceramics by electric current concentration

Electric current activated/assisted sintering (ECAS) techniques, such as electrical discharge sintering (EDS) or resistive sintering (RS), have been intensively investigated for longer than 50 years. In this work, a novel system including an electrically insulated graphite die for Spark Plasma Sintering (SPS) is described, which allows the sintering of any refractory ceramic material in less than 1 minute starting from room temperature with heating rates higher than 20006C/min and an energy consumption up to 100 times lower than with SPS. The system alternates or combines direct resistive sintering (DRS) and indirect resistive sintering (IRS). Electrical insulation of the die has been achieved through the insertion of a film made of alumina fibers between the graphite die and the graphite punches, which are protected from the alumina fiber film by a graphite foil. This system localized the electric current directly through the sample (conductive materials) as in DRS and EDS, or through the thin graphite foil (non-conductive materials) as in IRS, and is the first system capable of being used under EDS or RS conditions independently combining current concentration/ localization phenomenaPeer reviewe

Effect of residual compressive surface stress on severe wear of alumina-silicon carbide two-layered composites

Ceramics consisting of Al2O3 with a surface layer of Al2O3-10 vol% SiC have been fabricated by hot pressing. The residual compressive stress at the composite surface due to the difference in thermal expansion between the two layers has been measured experimentally by Cr3+ fluorescence microspectroscopy. The wear resistance in the severe wear regime of the two-layered samples was higher than those of a reference single-layer Al2O3-10 vol% SiC sample. The improvement in the wear resistance was due to a decrease in the amount of surface pullout which was attributed to the presence of the biaxial residual compressive stress in the surface layer of the specimens