21 resultados para Process Re-engineering
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
The better models of e-Gov posit high levels of informational communication between citizen and state. Unfortunately, in one area, that communication has traditionally been poor: that is, access to sources of law. There have been a number of reasons for this, but a primary one has been that law was historically mediated for the citizen by the legal profession. This situation is changing with ever increasing numbers of unrepresented litigants being involved at all levels of national court systems in each and every country as well as a generally higher level of intrusion of legislation into everyday home and business life. There have been attempts to improve access through internet based services, but these have improved communication (‘understanding of law’) to only a limited extent. It may be time, this article suggests, to consider re-engineering legal sources so that they better fit the needs of eGov.
Resumo:
Thermoforming processes generally employ sheet temperature monitoring as the primary means of process control. In this paper the development of an alternative system that monitors plug force is described. Tests using a prototype device have shown that the force record over a forming cycle creates a unique map of the process operation. Key process features such as the sheet modulus, sheet sag and the timing of the process stages may be readily observed, and the effects of changes in all of the major processing parameters are easily distinguished. Continuous, cycle-to-cycle tests show that the output is consistent and repeatable over a longer time frame, providing the opportunity for development of an on-line process control system. Further testing of the system is proposed.
Resumo:
This paper describes the development of neural model-based control strategies for the optimisation of an industrial aluminium substrate disk grinding process. The grindstone removal rate varies considerably over a stone life and is a highly nonlinear function of process variables. Using historical grindstone performance data, a NARX-based neural network model is developed. This model is then used to implement a direct inverse controller and an internal model controller based on the process settings and previous removal rates. Preliminary plant investigations show that thickness defects can be reduced by 50% or more, compared to other schemes employed. (c) 2004 Elsevier Ltd. All rights reserved.
Resumo:
New elements associated withWeb 2.0 relating to interactivity and end-user focus have combined with the availability of newlevels of information to encourage the development of what may be termed a Gov 2.0 approach.This, in combination with recent initiatives in the modernising government programme, has emphasised new levels of public participation and engagement with government as well as a re-engineering of public services tomake them more responsive to their end users. Adopting a governmentality perspective, it is argued that this involves a wider process of governing through constructing and reconstructing ideas of the public, community and individual citizen-consumers who take on a role in their own governance. It is argued that this fundamental re-working of the nature of what is public represents a constitutional change that is perhaps more signi¢cant than the constitutional reform programme directed to formal government which attracts more attention
Resumo:
The thermoforming industry has been relatively slow to embrace modern measurement technologies. As a result researchers have struggled to develop accurate thermoforming simulations as some of the key aspects of the process remain poorly understood. For the first time, this work reports the development of a prototype multivariable instrumentation system for use in thermoforming. The system contains sensors for plug force, plug displacement, air pressure and temperature, plug temperature, and sheet temperature. Initially, it was developed to fit the tooling on a laboratory thermoforming machine, but later its performance was validated by installing it on a similar industrial tool. Throughout its development, providing access for the various sensors and their cabling was the most challenging task. In testing, all of the sensors performed well and the data collected has given a powerful insight into the operation of the process. In particular, it has shown that both the air and plug temperatures stabilize at more than 80C during the continuous thermoforming of amorphous polyethylene terephthalate (aPET) sheet at 110C. The work also highlighted significant differences in the timing and magnitude of the cavity pressures reached in the two thermoforming machines. The prototype system has considerable potential for further development.
Resumo:
The prediction of the pressure drop for turbulent single-phase fluid flow around sharp 90° bends is difficult owing to the complexity of the flow arising from frictional and separation effects. Several empirical equations exist, which accurately predict the pressure loss due to frictional effects. More recently, Crawford et al. [1] proposed an equation for the prediction of pressure loss due to separation of the flow. This work proposes a new composite equation for the prediction of pressure drop due to separation of the flow, which incorporates bends with ratio R/r <2. A new composite equation is proposed to predict pressure losses over the Reynolds number range 4 x 103-3 x 105. The predictions from the new equation are within a range of -4 to +6 per cent of existing experimental data.
Resumo:
Computational fluid dynamic modelling was carried out on a series of pipe bends having R/r values of 1.3, 5, and 20, with the purpose of determining the accuracy of numerical models in predicting pressure loss data from which to inform one-dimensional loss models. Four separate turbulence models were studied: the standard k-epsilon model, realizable k-epsilon model, k-omega model, and a Reynolds stress model (RSM). The results are presented for each bend in the form of upstream and downstream pressure profiles, pressure distributions along the inner and outer walls, detailed pressure and velocity fields as well as overall loss values. In each case, measured data were presented to evaluate the predictive ability of each model. The RSM was found to perform the best, producing accurate pressure loss data for bends with R/r values of 5 and 20. For the tightest bend with an R/r value of 1.3, however, predictions were significantly worse due to the presence of flow separation, stronger pressure gradients, and high streamline curvature.
Resumo:
his paper develops a typology of strategic options for small firms in the furniture industry and examines the extent to which firms are re-engineering their strategies in response to profit performance. Empirical analysis is based on data from 39 firms with between 10 and 100 employees in the Irish furniture industry. Three main results emerge from the analysis. First, firms in the Irish furniture industry predominantly adopt “simple” business development strategies. Secondly, in terms of profit performance, we find no evidence that simple strategies unambiguously outperform more complex approaches. Instead, the success of both simple and complex business strategies is directly related to the strength of firms’ resource base. Finally, systematic differences were found in firms’ ability or willingness to re-engineer their strategies in the light of their profit performance.
Resumo:
This paper presents the rational for the selection of fluids for use in a model based study of sub and supercritical Waste Heat Recovery (WHR) Organic Rankine Cycle (ORC). The study focuses on multiple vehicle heat sources and the potential of WHR ORC’s for its conversion into useful work. The work presented on fluid selection is generally applicable to any waste heat recovery system, either stationary or mobile and, with careful consideration, is also applicable to single heat sources. The fluid selection process presented reduces the number of potential fluids from over one hundred to a group of under twenty fluids for further refinement in a model based WHR ORC performance study. The selection process uses engineering judgement, legislation and, where applicable, health and safety as fluid selection or de-selection criteria. This paper also investigates and discusses the properties of specific ORC fluids with regard to their impact on the theoretical potential for delivering efficient WHR ORC work output. The paper concludes by looking at potential temperature and pressure WHR ORC limits with regard to fluid properties thereby assisting with the generation of WHR ORC simulation boundary conditions.
Resumo:
Melt viscosity is one of the main factors affecting product quality in extrusion processes particularly with regard to recycled polymers. However, due to wide variability in the physical properties of recycled feedstock, it is difficult to maintain the melt viscosity during extrusion of polymer blends and obtain good quality product without generating scrap. This research investigates the application of ultrasound and temperature control in an automatic extruder controller, which has ability to maintain constant melt viscosity from variable recycled polymer feedstock during extrusion processing. An ultrasonic modulation system has been developed and fitted to the extruder prior to the die to convey ultrasonic energy from a high power ultrasonic generator to the polymer melt. Two separate control loops have been developed to run simultaneously in one controller: the first loop controls the ultrasonic energy or temperature to maintain constant die pressure, the second loop is used to control extruder screw speed to maintain constant throughput at the extruder die. Time response and energy consumption of the control methods in real-time experiments are also investigated and reported this paper.