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3.1 Primary sources of synthetic polymers

The most important primary sources of synthetic polymers are crude oil, natural gas and, to a minor extent, coal. Because all are primarily fuels rather than sources of materials, the manufacture of polymers is susceptible to changes in price or supply. However, this is also true of other materials, since fuel costs are an important component of metal, ceramic and glass manufacture where very high reaction temperatures are needed for reduction of ore to metal and/or smelting. Where polymer ma
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2.3.1 Structural isomerism

In the saturated hydrocarbons, whose structural formulae are shown in Figure 16, it is not possible to form distinct isomers with just three or less carbon atoms linked together. There is only one way in which one carbon and four hydrogen atoms can be linked together, the single compound being methane, CH4. A simila
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2.4 Models as part of systems work

Thinking systemically involves identifying systems relevant to some situation, and models are invariably used as part of this process. An example of this forms part of Checklands' Soft Systems Methodology (SSM) (Checkland, 1981). One aspect of this methodology concerns the formulation of a root definition of some system that is relevant to the situation of interest and the construction of a conceptual model of this system. The root definition is a concise, verbal description of what a
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2.1 Defining ‘model’

The word ‘model’ has a range of colloquial and technical interpretations, so we need first to establish the way in which this unit uses the term. As a start, we might suggest that a model is a simplified representation of reality, but even that simple definition raises some quite significant philosophical questions. A profound question is ‘what is reality?’ and I will briefly mention the distinction between modern and postmodern views of this later as an aside. Without getting
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4.5 Methodologies associated with information technology

I recently undertook an exercise in a company that manufactures various types of agricultural machinery. I was happily using the term ‘system’ in its general sense when a senior manager stated ‘In this organization we use the word “system” to mean a computer system, for other types of procedure or activity we use “process”.’ This is a commonly encountered distinction and the evolution of computer systems, and particularly software, has been an important contributor to systems
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Stage 2: The situation analysed

The first step is to develop a picture (called in soft systems terminology a rich picture) that encapsulates all the elements that people think are involved in the problem. Once the rich picture has been drawn, the analyst will attempt to extract ‘issues’ and key tasks.

Issues are areas of contention within the problem situation. Key tasks are the essential jobs that must be undertaken within the problem situation.

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4.1 Introduction

Additional material for this unit, by David Chapman, January 2005

The start of optical-fibre communication is generally identified with a paper published in 1966 (Kao and Hockham, 1966). It was not until about ten years later that it was commercially viable, but from then on there was more or less continuous development, with substantial research effort taking place both in industry and universities.

Innovation continues today, and this additional material introduces some
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Introduction

This unit is from our archive and it is an adapted extract from Digital Communications (T305) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer in this curriculum area.

By using optical fibre, very high data rates (gigabits per second and higher) can be transmitted over long d
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1.8 ‘Ethics’, ‘ethical’ and authority

There is some confusion over the uses of the terms ‘ethical’ and ‘ethics’. Often people use the adjective ‘ethical’ to signal things that they would expect virtuous people to do. That is they use the word ‘ethical’ instead of ‘good’. Companies, institutions and even governments might claim to have ‘ethical’ policies. Probably such a policy declares the ideology. For example, saying that ‘sustainability is ethical’ may be part of an individual's ethic but it is a ta
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6.7 Cost-benefit analysis

  • 17. Does the case clearly and unequivocally demonstrate that benefits outweigh costs?

In some contexts ‘cost-benefit analysis’ implies some specific formal method of assessing costs in relation to expected benefits. For example, i
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3.2 Business operations: function or process?

Traditionally, an enterprise's activities are organised according to a structure based on the well-known business functions: marketing, purchasing, finance, human resources, research and development (R&D), operations, and so on. The exact function title varies from organisation to organisation, but each function has its own more or less well-defined sphere of activity. It carries out its various tasks and passes on information or artefacts to other functions for them to work on. For example,
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7.3.2 Evaporation

The simplest vacuum deposition technique is to heat an ingot of metal in a crucible under vacuum, releasing metal vapour that coats everything in its path. This can be done either under high vacuum (< 0.1 mbar), in which case only surfaces in a line of sight from the source will be coated, or in a low-pressure atmosphere, when the vapour is scattered by gas atoms and can go around corners, making batch processing of multiple wafers possible.

This rather simple technique is fast and chea
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3.1.3 Micro lenses

A smart way to compensate for surrendering area to data transfer is to build in microscopic lenses at each pixel: the processing sequence that is used to manufacture the MOS devices already involves transparent polymeric material and, calling again on the ingenuity of the designers of microelectronics, significant enhancement to optical efficiency can be won.


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5.2 Material comparisons

I want to depart from the specific example of the bicycle to make some more general points.

In most simple structural analysis the self-weight of the structure is ignored, as it is considered to be small in comparison with the loads carried. However, as an illustration of engineering practice in the search for efficient structures to employ in product design, it is worth examining how the strength and weight of particular materials compare.

These comparisons are illustrated throug
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4.5.1 Mathematical models

Computers in the last few decades have, in many cases, made mathematical modelling a lot easier. Models that used to require hours of manual cranking through long equations can now be created on a screen using specialist software. Processes can be recreated – modelled – in the time it takes to press a few buttons.

For example, when designing a pipe network to carry a gas or fluid, such as in the village water supply problem, you might wish to know how the flow would be distributed w
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Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions) and is used under licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

Video Materials

This video extract is from Coast Se
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1 The Forth Road Bridge

Edinburgh reaches over the Firth of Forth with two great bridges – the photogenic Victorian Forth Rail Bridge and the slender 1960s Forth Road Bridge. The latter suspends the road from cables, but it is being threatened by rust. Water has found its way inside the cables, causing them to rust and weaken. It is predicted that in 2014 they may have to stop heavy goods vehicles using it and possibly close it altogether in 2019.

The following video, an extract from BBC's Coast Serie
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Learning outcomes

After studying this unit, you should be able to:

  • understand the basic structural issues of the Forth Road Bridge;

  • give examples of how engineers are trying to alleviate the wear and tear on the bridge.


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4 Unit summary

Sound recording really took off once the public's demand for recorded music had been acknowledged. The choice of technology, cylinder or disc, was determined more by the selection of the artist and material than the quality of the sound. Development of disc technology was slow due to the lack of better alternatives, remaining substantially unchanged for over fifty years. The development of radio broadcasting caused a slump in the record industry but eventually it not only provided improvement
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3.4 Compact cassettes

The use of magnetic tape for home use has always been somewhat problematic. Whilst it offers several advantages over discs, being capable of high-quality sound, substantially free from surface noise and able to make personal recordings, tape never became so popular as to make any serious inroads into the sales of discs. Why should this be the case? The answer is one of convenience, for magnetic tape has always been difficult to handle compared with discs – threading the tape through the mac
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