This course examines how small features can be etched and cut out of solid materials at a very small scale.

This OpenLearn course is an adapted extract from the Open University course T356 Engineering small worlds: micro and nano technologies.

Author(s): The Open University

This unit starts by giving an overview of the two main categories of disasters: disasters of natural origin and disasters of human origin. It then analyses the Tay Bridge disaster, which was caused by mechanical failure.

Inevitably, human factors emerge as important in many major disasters. They may involve the failure by engineers, designers or managers to recognise faults in safety-critical products, or managers overriding the design team for other reasons â€“ such as keeping to a dea
Author(s): The Open University

Theories in Technology Evaluation
This free course, Theories in Technology Evaluation, is devoted to exploring and analysing the theoretical and political nature of evaluation and assessment. It introduces theories and paradigms that play important roles in how we design, conduct and use evaluations and assessments, and deals with the thorny issue of participation in evaluation. Author(s): Creator not set

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Author(s): The Open University

How can we explain a sudden switch of behaviour at a particular temperature? There must be two competing influences (say X and Y) that depend differently on temperature. Figure 23 indicates how a unique temperature (a so-called critical temperature, Tc) arises
Author(s): The Open University

Let's look graphically at the way the rate of a thermally activated process changes with temperature. Figure 16 shows two rates with different activation energies of 1.0 and 0.5 eV â€“ which curve is which?

Author(s): The Open University

Thermally activated processes are those that get going not because of average effects, but because the fraction of particles in the tail of the distribution increases with temperature. This is a basic property of the thermal distribution we have been discussing. For instance, what would take 30Â 000 years at room temperature may happen in under one second at 1000 K if it depends on how many particles have an energy in excess of 1 eV.

The next step in the study of energy distribut
Author(s): The Open University

Thermal energy is associated with random motion â€“ that is, in effect, a definition. Because it is random, it only makes sense to talk about it in connection with a large population of atoms. I began with fifty million million million silicon atoms â€“ that should be enough. If whatever motion they have is random, some may have lots of it, others very little. With such a large population it is reasonable to try to think about an average motion or, better, to define an average energy of the p
Author(s): The Open University

Formal projects are a familiar part of nearly all work situations and are often a staple part of some organisations. Because of this it is worth looking at some of the features of formal projects and their management, as they have some different characteristics from other ongoing activities.

To write about projects, we have to define what they are and describe how they arise. Projects and project work are often contrasted with process: 'process', in this sense, describes the normal day-
Author(s): The Open University

Clearly, it is not possible to devise a set of rules which, if followed, would lead inexorably to team effectiveness. The determinants of a successful team are complex and not equivalent to following a set of prescriptions. However, the results of poor teamworking can be expensive, so it is useful to draw on research, experience and case studies to explore some general guidelines. What do I mean by 'team effectiveness'? â€“ the achievement of goals alone? Where do the achievements of individu
Author(s): The Open University

In addition to the traditional types of teams or groups outlined above, recent years have seen the growth of interest in two other important types of team: 'self-managed teams' and 'self-organising teams'.

During the 1990s many organisations in the UK became interested in notions of empowerment and, often as a consequence, set up self-managed or empowered teams. An Industrial Society Survey (1995) commented:

Author(s): The Open University

Many techniques have been used to design connectors that align the fibre ends accurately with high reliability and a long lifetime. The development of such components, at a low enough price, has been an important part of the overall development which has made fibre a feasible proposition for commercial transmission systems.

With fibre attenuation down to 0.2 dB kmâˆ’1 (for single-mode fibre), the losses resulting from connectors and splices can be very significant over a whol
Author(s): The Open University

Because there is only one mode in single-mode fibre, there is no multimode distortion but pulses are spread by dispersion.

Dispersion is the effect of different frequencies propagating at different speeds, and there are various mechanisms in optical fibre which mean that in general a fibre is dispersive. Given that dispersion takes place, a transmitted pulse will be spread because different frequency components in the pulse will take different lengths of time to propagate.
Author(s): The Open University

The problem we will look at in this section concerns the analysis of the design of a component used in cars that are fitted with airbags. The airbag has to be inflated rapidly when an electronic circuit in the system decides that a serious collision is taking place. The crucial component in the electronics is the accelerometer, which therefore has to be extremely reliable. Motor manufacturers have turned to a technology called MEMS (micro-electromechanical systems) for these accelerometers, b
Author(s): The Open University

Over the centuries, engineers have faced and solved a huge number of problems of one sort or another. Each time a problem is solved, knowledge is advanced, something usually gets written down, and so today we have a wealth of experience to draw on. Equally, problem-solving techniques have also been developed and evolved through use and refinement, which is rather handy. Not only do we have some idea of existing solutions to similar problems, but we also have an indication of how to go
Author(s): The Open University

Nitrate in water has become a significant problem and the EU Directive sets a maximum admissible concentration of 50 g mâˆ’3 measured as NO3âˆ’. This is equivalent to 11.3 g mâˆ’3 as N. High nitrate levels can cause cyanosis or methaemoglobinaemia in babies. Legislation allows the designation of nitrate-vulnerable zones and these help to prevent nitrate levels in natural waters increasing in affected areas.

Ion exchange is used in some
Author(s): The Open University

Bacteria are organisms of special significance to the study of clean and polluted waters because they break down organic matter. While most of them are not harmful to humans, some bacteria (e.g. Clostridium) are pathogenic. Most bacteria are retained on a filter of pore size 0.45 Î¼m and all bacteria are trapped on a filter of 0.22 Î¼m. They are important in sewage treatment, and in solid waste disposal. They are extremely abundant in almost all parts of the aquatic env
Author(s): The Open University

Movement of infiltrated water downwards through the zone of aeration (Figure 5) is known as percolation. The infiltrated water which does not remain held by capillary forces in the surface soils moves by the action of gravity through the unsaturated layers of soil or rock until it arrives at the water table. Here the percolated water joins the body of groundwater which seeps slowly to the sea.

Author(s): The Open University

As air rises it expands, owing to the decrease in pressure with height, and as it expands, in theory it cools at an average rate of 1Â°C for every 100 m of altitude. As the air cools, it becomes saturated with water vapour which condenses around small particles in the air. These particles may occur naturally, such as soil particles or salt particles residual to evaporation of sea spray, or they may be produced artificially during combustion. A measure of the necessary cooling to produce conde
Author(s): The Open University

Now you have worked through this section, reflect on your own version of what learning is, as you drafted it for your learning file at the start of this section. Did you give more emphasis to the outcomes of learning, or to the process? Or did you find a way of balancing the two? Try to revise your own wording to your own satisfaction.

Learning is â€¦

Do remember that definitions of learning often reflect the kinds of learning that were most important to us at the time, or were in
Author(s): The Open University