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3.3 Nuclear energy

Nuclear energy is based on harnessing the very large quantities of energy that are released when the nuclei of certain atoms, notably uranium-235 and plutonium-239, are induced to split or 'fission'. The complete fission of a kilogram of uranium-235 should produce, in principle, as much energy as the combustion of over 3000 tonnes of coal. In practice, the fission is incomplete and there are other losses, but nevertheless nuclear fuels are more highly concentrated sources of energy than fossi
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Glossary

Glossary item
Definition
atom
the smallest amount of a chemical element that still retains the properties of that element.
biodiversity
a contraction of 'biological diversity', in general it describes the variety of life on Earth and specifically the total sum of the genes, species, habitats and ecosystems in a given environment.
Brundtland report
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Acknowledgements

Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

This free course is adapted from a former Open University course called 'Living in a globalis
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4.1 Introduction

We have seen in SAQ 18 of Section 3.4 how some sets of points of the complex plane can be described algebraically in terms of operations on C. We now use the modulus function to take this a step further by defining discs in the complex plane. As we shall see, discs are extensively used in arguments involving l
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2.1.1 Preparation

Prepare to watch the video in just the same way as you would prepare to study written material. You will need to have a suitable environment in which you should be relatively undisturbed and able to concentrate for the full length of each video extract. You will need to be able to take some notes as you watch – it is easy to forget the key points if you leave note taking until the video is finished, and it will be important to record your immediate reactions to some of the images.

I
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Groups and teamwork
Are you always the quiet one when it comes to group discussion? This free course, Groups and teamwork, will help you improve your working relationships with other people in groups of three or more. The course also deals with project life cycles, project management and the role of the leader. First published on Mon, 10 Dec 2018 as Author(s): Creator not set

Introduction

In this course we examine one factor that very often seems to be found skulking around close to problems and solutions: temperature.

Almost whatever we do, wherever we are, temperature changes. Stay in the same spot and you'll find daytime and night-time temperatures can be markedly different. You may even find significant changes in temperature during the day. When moving you can encounter more rapid variations. For example, an aircraft might leave a tropical runway where the air tempe
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Learning, thinking and doing
How do we learn? Understanding how is the key to learning more effectively. This free course, Learning, thinking and doing, looks at the three main categories of theories: the acquisitive, constructivist and experiential models of learning. There is no right way to learn but developing an active approach will ensure that you are open to new ideas. Author(s): Creator not set

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Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Additive manufacturing
This free course, Additive manufacturing, introduces you to its key concepts. It covers the fundamentals of the additive manufacturing (AM) process, the steps involved in creating a model and building an artefact, the materials and techniques used, as well as the design implications and the factors which affect the functionality of the finished parts. First published on
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2.5 Living systems and information flows

Understanding the role of information flows in feedback relationships is often confusing. It is relatively easy to visualise flows of energy and matter (ecosystem food webs, water flowing through a rainforest ecosystem, etc). But how does information ‘flow’ within feedback loops, and how does this affect systems?

The first point to make clear is that information is only meaningful to those systems that can perceive it. In other words, these systems need to have components th
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3.1 (2A): Exploring the global implications of different mindsets

In this activity the aim is to investigate the implications of different mindsets with regards to the future unfolding of events on a global scale.

Activity

So far, you have focused your attention on exploring your p
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6.3 Summary of Section 6

  • In trying to find solutions to the specific problem of the water-boiler, where the need was for a particular response to a certain temperature change, we have gone into the principles behind the three classes of temperature effect – gradual, accelerating and sudden. This has provided you with mathematical models that are of real use in putting definite numbers to the magnitudes of these effects in any designs that are proposed. The ability to do this is ju
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4.4 Summary of Section 4

  • Thermal energy is a random thing, so any group of particles possessing it will have a distribution of kinetic energies.

  • The fraction of particles with energy greater than an amount E1 is proportional to exp(−E1/kT).

  • Thermally activated rates follow Arrhenius's law and are characterised by an activation energy.

  • Diffusion in solids and electrical conduction in ceram
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4.2.2 The significance of the average energy

The average thermal energy of the atoms in a solid indicates how much they are 'rattling' or vibrating around their mean positions. Since the atoms are close together, virtually touching, and because atoms are almost incompressible, they cannot get much closer. But they can get further apart. So, since thermal energy is manifested in the vibrations of the atoms, bigger vibrations mean that the atoms must spend more time further apart. On average then, there is a tendency for a solid to expand
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3.1 Modelling properties

This section provides a model for properties interpreted in terms of the average thermal energy of all the constituent atoms of a material. Since absolute temperature T is a measure of average atomic kinetic energy, we shall expect to be looking at properties that change gradually with T, roughly proportionally, over a wide range. In terms of the classification introduced in Author(s): The Open University

2.3 How things change with temperature

The temperature-dependent effects used in most thermometers have a fairly steady change over a good range of temperature (Figure 3a). By contrast, phase changes, of which melting and boiling are the common examples, happen at sharply critical temperatures (Author(s): The Open University

Stage 5: Formulating measures of performance (how will we know when we have arrived?)

The hard systems approach emphasises the need to have measurable means of assessing the efficacy of any potential solution or design, but recognizes that this may not always be possible.


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5.7 Being ethical

As outlined in Table 2, ethics within systemic practice are perceived as operating on multiple levels. Like the systems concept of hierarchy, what we perceive to be good at one level might be bad at another. Because an epistemological position must be chosen, rather than taken as a given, the cho
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5.5 Distinctions about systems practice

A tension has existed throughout the history of Western thought around whether to focus on parts or the whole. The practice that springs from this history carries the same tension. This tension has been particularly visible within science and philosophy for a long time and it gives rise to different approaches.

Emphasizing the parts has been called mechanistic, reductionist or atomistic. An emphasis on the whole has been called holistic, organismic or ecological. As Fritjof Capra (1996)
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3.6.1 Stiffness

Just how compliant does an AFM cantilever have to be to enable it to follow the undulations in a surface on an atomic scale? How can we find out? It turns out that this is easier than at first it seems.

A simple assumption we can make is that the compliance of the cantilever should be appreciably greater than that of a typical bond that holds atoms to one another. Here's one way in which a rough estimate of the stiffness (the force required to cause a given deflection) of the bonds in a
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