2.3 Divisions that matter: thinking through territories Without losing our focus on the planet as a whole, it is time now to return to what Paani Laupepa from Tuvalu refers to as the ‘front line’ of climate change: those islands that are particularly vulnerable to rising sea level and associated climatic hazards (Lynas, 2003). It has often been said that low-lying coral islands like Tuvalu or Kiribas in the Pacific Ocean, or the Maldives in the Indian Ocean, are acting as a kind of early warning system for global climate change. Sea level is e
1 Dividing the planet A good globe can set you back quite a lot of money. Of course, I don't mean the little moulded plastic planets or the globes you can blow up as if the world were a beach ball, but the decent sized ones that sit solidly on turned wooden bases and quietly emanate authority from the corner of a room. Yet these days, it hardly seems worthwhile making such an investment. Countries appear to change their colour, their shape or their name with remarkable rapidity. It has become a cliché to po
Learning outcomes After studying this unit you should be able to: understand some of the key ways in which globalisation is shaping the world today; give examples of how ideas of 'proximity' and 'distance' can be used to understand an increasingly demanding world; illustrate the importance of recognising the liveliness of the natural world.
1.3.1 Parts consolidation The most obvious use of polymers is for enclosures for working equipment, such as power and garden tools as well as cooking devices, and electronic products such as computers, video recorders and fax machines (as well as the products used in those machines). They are not just boxes for containment; such plastic enclosures can incorporate carefully designed ribs, webs and flanges on the hidden, inner sides to hold working components securely in place when in operation (Figure 9). 5.1 Introduction: the general framework The general framework of systems engineering adopted in the course consists of: a hierarchy of elements; aims associated within its outputs and process; a set of principles; a division into technical and managerial components of the process. The lexicon of system engineering used in the course contains the hierarchy of elements:
strategy: meaning the accumulated decisions concerning the areas in which an organisation operates and its lon 3.3 Optical amplifiers
Figure 22 shows in outline one possible structure for an Erbium-doped fibre amplifier (EDFA). 2.4.3 Polarization mode distortion Because light is an electromagnetic wave, it has a ‘state of polarization’, which, for light in single-mode fibre, is at right angles to the path of the fibre. If you've not encountered electromagnetic waves before, all you need to appreciate is that as light travels down the fibre the electromagnetic field has an orientation across the fibre (Author(s): 2.4.1 Multimode distortion With multimode fibre, the main cause of pulses spreading is the multiple paths that signals can traverse as they travel along the fibre. This phenomenon of multimode distortion is illustrated in Figure 5. 2.2 Fibre types A strand of glass (or plastic, but the best performance comes from glass) has a core surrounded by a cladding, where the refractive index of the glass in the core is higher than that of the cladding (see the box on ‘Refractive index>’). Light is contained within the core by < 1.1 Uses of optical fibre in communication Using optical fibres, very high data rates (gigabits per second and higher) can be transmitted over long distances (tens of kilometres) without amplifiers or regenerators. As a consequence, optical fibre has completely superseded copper wires as the primary medium for cabled transmission over long distances. Until recently, however, optical fibre has been used less in LANs, where twisted-pair copper cable has been dominant. Similarly, fibre has been slow to penetrate the access network, from Learning outcomes After studying this unit you should be able to: convert between wavelengths and frequencies; describe the main differences between lasers and LEDs as used as light sources for optical-fibre communications systems; describe the difference between direct and external modulation of a laser; describe the difference in structure and performance of step-index multimode, graded-index multimode and single-mode optical fibres; d 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 2.0 Licence Grateful acknowledgement is made to the following sources for permission to reproduce material within this unit: 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 2.0 Licence Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit: 5.1 Phase and phase difference In this section I am considering sine waves that have the same frequency, but are out of step with each other. Suppose we have two detectors at fixed points, A and B. At this moment in time A is in a high pressure region and B in a low pressure region. If we were to look again shortly later B would now in a high pressure region and A in a low pressure region. The pressures at A and B would be out of step with each other. The pressure variation at B is not in phase with that at A. The ex 1.1 Music and technology Music technology in one guise or another is part of everybody's life, because music is a part of almost everybody's life. For instance, if you are an instrumental performer of music, professional or not, then your instrument, be it the harp or the rock'n'roll drums, will be the result of considerable technological expertise on the part of the instrument maker. On the other hand, if you are not a performer but like to listen to music, the chances are that most of your listening is done via a h 10.3.1 Cats eyes and road conditions Sometimes the discontent comes from the fact that there isn't a product to satisfy a particular need. Percy Shaw was a road mender who was aware of the dangers of driving along unlit, often fog-bound, roads. One night in 1933 he was driving his car near his home in the north of England when his headlights were reflected in the eyes of a cat. This inspired him to invent the cat's-eye reflector that, when embedded at intervals in the centre of the road, reflected a vehicle's headlights and made 4.1 An explanation I will now elaborate on my answer from Exercise 1. I'm doing this because my internet search revealed more than I've written in the above answer, and to show that the invention of the telephone and its use by consumers is not as plain and simple as you may think. You we 1 Part 1 Investigating the innovation process In Part 1 I invite you to look around at the technological products in your home or at work and consider their development history and their impact on the lives of you and your family. I then define the key concepts associated with the process of invention, design, innovation and diffusion. Introduction This unit aims to provide an understanding of invention, design, innovation and diffusion as ongoing processes with a range of factors affecting success at each stage. You will gain an understanding of the factors that motivate individuals and organisations to invent, and the creative process by which individuals come up with ideas for new inventions and designs, and you will gain an understanding of the obstacles that have to be overcome to bring an invention to market and the factors that i 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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