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3.2.1 Social disruption

In return for being granted enhanced market access by developed countries, which turned out to be somewhat illusory, developing countries agreed to open up their own markets. Indeed, for supporters of the UR, this was its biggest achievement. One of the central propositions of economic theory is that under certain conditions free trade is beneficial to a country – but there are inevitably winners and losers. As a country adjusts to free trade, some sectors of the economy advance, while othe
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3.2 Exploring your quality of life

In this activity the aim is to develop and use a range of interdisciplinary indicators that describe your quality of life.

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Introduction

This unit will facilitate your own exploration of key environmental, social and economic threats that will converge to challenge communities in the near future. You will be required to develop this exploration according to three modes of modelling and communication: verbal, visual, and numeri
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5.5 Summary of Section 5

  • The phase of a material is characterised by its physical state (e.g. solid, liquid or gas), a distinctive arrangement of the atoms, and its chemical composition.

  • Material properties can change suddenly as the temperature increases or decreases, corresponding to changes of phase and the degree of order associated with the arrangement of atoms.

  • Shape memory alloys are examples of a wide range of useful engineering materials t
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2.1 Boiling water

Whether it's to wash clothes, make a cup of tea, or just make it safe to drink, water often has to be heated – sometimes to boiling point. There are many ways to do this, but a very common means is some form of electric water-boiler, such as a kettle or an urn. In all but the crudest ones, a device is fitted to ensure that heating does not continue once the boiling point of water is reached.

In deciding on the type and design of such a device, we can suppose that a company manufacturi
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1.5 Organising information

How confident are you that you know when it is appropriate to cite references (refer to the work of other people) in your written work?

  • 5 – Very confident

  • 4 – Confident

  • 3 – Fairly confident

  • 2 – Not very confident

  • 1 – Not confident at all

How confident do you feel about producing bibliographies (lists of references) in an appropriate format to accompany you
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6.4.2 Manufacturing the boat

Filling the mould is a serious problem in injection moulding: the lower the MFI, the more difficult it is to push molten polymer down narrow tubes into a metal mould. The engineers at Rolinx, the trade moulders who initiated the thermoplastic project, were working at the limits of their machinery in moulding such large objects in one operation. In the event, they were forced to blend the low MFI copolymer grade with a higher MFI grade material (GY702M) in order to achieve their objective (
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5.5 Orientation in polymers

Viscoelasticity, like thermodynamics, is concerned with the correlation of controllable variables and bulk, macroscopic phenomena. But one unique feature of polymeric materials is that the molecular unit, the polymer chain, can be highly anisotropic, i.e. the chain can be fully extended, or curled up in an amorphous equilibrium state without any net orientation. In fact, unoriented polymer is rarely encountered in manufactured products because of the different ways it is processed to shape. B
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5.2 Viscoelasticity of polymers

The simplest models for the deformation behaviour of an ideal material are those of Hookean linear elasticity in the solid state, and Newtonian linear viscosity in the liquid state. The end point of elastic deformation is either fracture or plastic flow, with the latter taking place at a constant yield stress in the ideal case. Whilst the behaviour of many real materials does approximate to these idealised models, that of polymers deviates markedly from them. In particular, their solid state
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4.3 Chain growth polymerization

Chain growth polymerization is basically a three-stage process, involving initiation of active molecules, their propagation and termination of the active chain ends.


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3.2.1 Thermal cracking

The bulk of the major monomer and intermediate, ethylene (C2H4), is still produced in the UK by steam cracking without the use of catalysts. Paraffinic feedstocks are best for optimising ethylene yields, and the severity of cracking is specified by the rate of disappearance of a marker compound, usually n-pentane. The severity of the reaction can then be defined as follows:

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Acknowledgements

The following material is Proprietary and is used under licence:

Text

Various pages: Arup, O., material accessed in January 2002 and December 2000, from.

Box 1: Inman, P. ‘Chaotic scheme that left families relying on food parcels’, The Guardian, 6 July 2005. © Guardian News and Media Ltd 2005.

Box 2: ‘Fly-away drones put robot air force plans off cou
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References

Abram, J. (2001) The Contribution of the Product Definition Process to a Successful High Volume Software Application, unpublished MSc dissertation, Milton Keynes, The Open University, p. 48.
Andriole, S.J. and Freeman, P.A. (1993) ‘Software systems engineering: the case for a new discipline’, Software Engineering Journal, vol. 8, no. 3, pp. 165–79. Reprinted in Dorfman and Thayer (1997), pp. 29–
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6 Summary

This unit has covered the background to systems engineering. It began by addressing the question ‘Why is systems engineering important?’ Two reasons were discussed:

  • projects go wrong, and the increasing incorporation of software means that they go wrong more often now than in the past

  • complication, complexity and risk are all increasing and need to be managed.

In the second section I examined the development of en
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5.2 The aims and principles of system engineering

The aims of systems engineering can be divided into those to do with its outputs and those associated with the process itself. As far as its outputs are concerned, systems engineering aims to ensure that:

  • the requirements of all the stakeholders are taken into account in engineering the system

  • the system, as engineered and realised, meets the requirements of stakeholders

  • the system, while meeting the req
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4.6 Systems engineering: the recent development of a discipline

The recent development of systems engineering can be dated from two events. First, following the lead of the US Department of Defense and its introduction of standards for contractors, systems engineering was taken up by companies such as Boeing, Lockheed Martin and, in the UK, British Aerospace, Marconi and the Lucas Group. Second, in August 1990, a group of individuals interested in systems engineering met in Seattle (Box 10 – extract from a paper presented at the International Committee
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3.11 Summary

This topic has introduced the systems approach, which is the foundation of systems engineering. The systems approach consists of three elements.

  • A set of concepts that can be used to understand the structural and dynamic features of operations systems.

  • Methodologies for managing change. Two current methodologies have been presented: the hard systems approach can be applied in situations where there is a measure of agreement about the
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Stage 6: Debate on feasible and desirable changes

The comparison undertaken in the previous stage can have two results.

  • It can cause opinions to change on the problem situation and the issues arising from it.

  • It can provide an agenda for change.

In either case (though both may result), the objective of this stage is to debate, with all concerned, the changes proposed to ensure that they are both desirable and feasible. The aim is to arrive at consensus about the prop
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Stage 4: Conceptual model

The conceptual (or activity) model contains all the activities that the relevant system would have to perform. The model is usually drawn as a block diagram.


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Stage 4: Generation of routes to objectives (how could we get there?)

This stage explores the different ways of achieving the defined objectives. It is the most imaginative and free-thinking stage of the approach. The idea is initially to generate as many ideas as possible, then to whittle the list down to two or three ‘definite possibilities’ that can be carried further in the development stage.


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