6.1 Defining amplitude Another important property of a sine wave we need to be able to specify is its amplitude. In essence, the amplitude of a sine wave is its size. Unfortunately there are various ways of defining what is meant by the size of a sine wave, and you are likely to come across many of them in material you look at outside this unit. Before I explain what our definition is, it will help matters if we look at what is meant by the average value of a sine wave. Figure 16 shows a sinusoidally a
1.3 Describing sound Let's now take a closer look at my list of categories from Activity 3, starting with item (a). In each of my descriptions of this sort, I referred to the source–cause of the sound: that is, an object or an instrument (the source of the sound) and ways of using it to produce a sou
7.2.4 Trap 4: words and wordiness I have seen some effective rich pictures with lots of words in them but they are quite rare in my experience. More often, lots of words make the rich picture less rich. Part of the later use of a rich picture might include looking for patterns. Words inhibit your ability to spot patterns. If you do use speech bubbles, use what people say, not your interpretation, unless the bubble is about some general attitude. Examples might be ‘Aaagh!’, ‘Help!’, ‘Oops!’ – the sort of th
2 Part 1 Starting the unit Welcome to T306_2 Managing complexity: a systems approach – introduction. As I write, I experience a sense of excitement. For me, as for you, this is the beginning of the unit. These are the first few sentences I'm writing and so, although I have a good idea of how the unit is going to turn out, the details are by no means clear. Nevertheless, the excitement and anticipation I, and maybe you, are experiencing now is an important ingredient in what will become our experiences of the u
13 Part 2: 4 Preparing for innovation Many inventors have said that having the idea for an invention is the easy part. This is often demonstrated by the frequency of examples of simultaneous invention. At one exhibition of inventions I attended there were three separate portable ladders to escape from fires, two systems for using rainwater to flush toilets, two types of portable vehicle wheel clamp, and two methods of reducing red-eye in flash photography. In most cases of technological innovation only one of the competing techno
10.5 Desire to help others This is a less common motivation but it shows not everyone is driven by money. In 1991 the inventor Trevor Baylis saw a BBC documentary about the spread of HIV/AIDS in Africa. What was needed was a way of broadcasting the safe-sex message to people in areas without electricity and where batteries for a radio could cost a month's wages. Solar power wouldn't necessarily help as most people who could get to a radio listened in the evening after work. While absorbing this information he ima
9 Part 2: Invention Having taken a broad look at the whole innovation process from invention to diffusion, I'll go back and look more closely at what motivates individuals and organisations to invent. Then I'll consider how people generate ideas for inventions and the designs based on the inventions.
4.4 What was innovative about the telephone? The most obvious innovative aspect was that speech was being transmitted, so in principle anyone could use a telephone for communication. The use of the telegraph required skilled operatives. A message had to be translated into the dots and dashes of Morse code and transmitted using a single keypad making and breaking the connection in an electrical circuit. At the other end of the wire another Morse operator translated the received clicks into the words of the message. With the telephone no
1.2.2 Visualisers and verbalisers A major point about diagrams is that some people naturally relate well to them and use them frequently, while others tend to prefer textual material. The former are sometimes referred to as visualisers and the latter as verbalisers. There is nothing wrong with either of these tendencies, but in subjects like systems thinking, social science or technology, where text and diagrams support each other, it is important to be comfortable with both. In addition, it is helpful to rememb
1.1.3 Features of diagrams As there is variety in the types of diagrams we can see and use we need to think more broadly about what diagrams are trying to represent. One distinction which follows on from the discussion above is:
Analogue representations: these diagrams look similar to the object or objects they portray. At their simplest they are photographs of real objects and at their most complicated they are colourful, fully labelled drawings of the inner workings o
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4 Who are the users? This section reveals that ‘users’ can include a wide variety of people – not just the final purchasers or consumers of a product. The section also makes the case for strong user representation in the design process. Of course, it is not only me who uses the various products in my home; other people use them as well, both members of the family and visitors. Sometimes the range of users of a product, and their different needs, can be diverse. And in addition to the obvious or intend
5.8.1 Nitrate removal Nitrate in water has become a significant problem and the EU Directive sets a maximum admissible concentration of 50 g m−3 measured as NO3−. This is equivalent to 11.3 g m−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
5.6 Filtration In filtration, the partially treated water is passed through a medium such as sand or anthracite, which acts as a ‘strainer’, retaining the fine organic and inorganic material and allowing clean water through. The action of filters is complex and in some types of filter biological action also takes place. Sand filters are used in water treatment to remove the fine particles which cannot be economically removed by sedimentation. They have been effective in removing Cryptosporidium,
3.4.1 Plant nutrients Plant nutrients are necessary in varying amounts for the growth, reproduction and well-being of growing plants. Of the major nutrients of plants, nitrogen and phosphorus are important growth-limiting factors in primary production (i.e. they are likely to run out before any other element needed by the plants). Both nitrogen and phosphorus enter watercourses from natural leaching by water of the soluble nitrates and phosphates found in soils and rocks, as well as from sewage effluent and
1 Some facts about water