2.1 Overview Catastrophes of human origin can be just as traumatic as those of natural origin, and are studied with even greater intensity for their causes. There are several ways disasters of human origin can be classified, depending on cause or size or origin. Another way of looking at them is by the kind of human activity – perhaps mining, fishing or transportation. Equally, disasters could be classified according to the kind of event that occurred during the accident – perhaps collision, sinking,
1.2 Earthquakes and volcanoes The disasters that first come to mind are those where the earth itself changes in an unpredictable and sudden way: earthquakes volcanic eruptions tidal waves These natural phenomena are now known to be interconnected: earthquakes result from vast plates of the earth's crust meeting and moving against one another. Volcanic explosions, such as Krakatoa (1883) and Mount St Helens (1980) are also manifestations
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.
Acknowledgements The following material is Proprietary (see terms and conditions) and is used under licence Figure 7: The Royal Scottish Museum, Edinburgh Figure 8: The Royal Scottish Museum, Edinburgh Figure 20: taken from www.acmi.net.au/AIC/BLATTNER_STILLE.html Figure 13 and 25: Ampex GB Limited We also thank Nigel Bewley (British Library Sound Archive), Daniel Leech-Wilkinson (King's College, London) and Robert Philip
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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
3.5 Studio tape recorders The importance of tape recording to record production cannot be overemphasised. From its development until the coming of digital tape recorders in the late 1970s, the analogue tape recorder was at the heart of the professional music recording studio. Initially, the full width of the standard quarter-inch tape was used for making monophonic recordings. Stereo needed two tracks – one for each channel. Rather than doubling the tape width, a decision was made to halve the track width by incorpo
3.2 Recording on the wire A paper published by Oberlin Smith in an 1888 issue of Electrical World discussed the possibilities for recording sound using the property of magnetism. He envisaged a cotton thread impregnated with steel dust passing through a coil carrying a current controlled by a microphone. The variations with the sound in the strength of the current would cause corresponding magnetic fluctuations in the magnetic medium. Unfortunately he dismissed his idea because, as he said in his paper, he thou
2.6 Turning the handle The owners of the original hand-cranked gramophones were instructed that the standard velocity for ‘seven-inch plates’ was about 70 revolutions per minute. The owner was also warned that failure to turn the plate at the correct speed would lead to a lowering of the pitch if turned too slow, or a raising of the pitch if turned too fast. It is doubtful if true reproduction of the recorded sound was ever achieved by the owners of these machines! A better power source was needed and as electr
Learning outcomes By the end of this unit you should be able to: explain correctly the meanings of the emboldened terms in the main text and use them correctly in context; give a brief account of the history of the record industry; describe the methods used for storing analogue audio recordings introduced in the main text, highlighting their technological aspects; make informed judgements as to the quality of a sound recording through analysis of the a
Introduction This unit looks at the ways in which technology has influenced the music industry and how this has changed the way we listen to music and buy records. It is a brief history of the recording industry from its beginnings at the end of the nineteenth century. Step changes in technology will be highlighted in a story that often is as much about the people who built the industry and the recordings they made as about the technologies that were developed and used. Please note that Author(s):
Module team
Academic staff
Dr Alec Goodyear (course chair) Professor Nicholas Braithwaite Jan Kowal Dr Tony Nixon Dr Sally Organ Robin Harding (critical reader) James McLannahan (critical reader) Dr Martin Rist (critical reader) Dr George Weidmann (critical reader) Peta Jellis (course manager) P
T356 course team
External assessor
Acknowledgements Grateful acknowledgement is made to the following sources:
Figure 7 (a): PDB ID 1BKV Kramer, R. Z., Bella, J., Mayville, P., Brodsky, B. and Berman, H. M. (1990) ‘Sequence dependent conformational variations of collagen triple-helical structure’, Natural Structural Biology, vol. 6, pp. 454–57
Figure 7(b): PDB ID 1ATN Kabsch, W., Mannherz, H. G., Suck, D., Pai, E. F. and Holmes, K. C. (1990) ‘Atomic structure
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4 Engineering with proteins What are the prospects for designing and making new proteins for specific purposes? The technology exists to build polypeptide chains unit by unit in a test tube, but this is time-consuming and expensive. Often a more practical approach is to find ways of working with nature to produce useful substances in a form that we can use. This might involve extracting a naturally occurring protein and chemically modifying it in some way, or using genetic engineering to produce a particular protein in
3.1 Protein diversity Of course, our bodies can't just be made up of squidgy bubbles of phospholipid, or we would collapse in a heap on the floor! Stiffer frameworks, both inside and outside the cells, also exist and help to define shape and add strength. These frameworks are formed largely from structural proteins, a class of polymeric materials that form fibres and filaments to provide mechanical support for cells and tissues. Structural proteins are made inside cells but are often then moved into the spa
2 Construction with lipids The cell membrane is constructed from lipids. Chemically, lipids are a rather varied group of compounds that include all the substances you might already think of as fats or oils. What they have in common is that they are all insoluble in polar liquids like water, but soluble in organic (carbon-based) solvents: by this I mean the sort of smelly solvents you tend to find in paints, glues and degreasing agents; chloroform is one example. Lipids make up the fatty components of living organisms a
Learning outcomes After you have completed this unit you should be able to: describe and give examples of how self-assembly enables construction ‘from the bottom up’ in natural materials; explain what is meant by primary and higher-order structure in proteins and give examples; give examples of the range of functions carried out by proteins within cells; describe how a combination of strong and weak bonding within biopolymers and lipids is used to
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:
Author(s):
6 Radiation All the primary vibrators we discussed in the previous section can to some extent communicate vibrations to the surrounding air and hence radiate sound. However, some radiate sound better than others. Air columns, for example, radiate sound quite well. Even though only around 1% of the energy possessed by a vibrating air column is radiated away, this is enough to produce a clearly audible note. Similarly, circular membranes and circular plates are also good sound radiators. They have a
5.13.4 Pitches of notes produced by percussion instruments We have seen that none of the rectangular bar, the circular membrane and the circular plate have harmonically related natural frequencies. It may not surprise you to learn, therefore, that instruments containing these primary vibrators tend to produce notes that don't have a very well-defined sense of pitch. This is certainly true in the case of the cymbal, which has a circular plate as its primary vibrator. Whether a single cymbal is struck with a drumstick or two cymbals are crashed t
5.13.3 Circular plate By now you shouldn't be at all surprised to learn that when a circular plate that has an outer rim that is free to vibrate is struck, the plate will vibrate in a number of modes at the same time. The first four modes of vibration of a circular plate with a free edge are shown in Figure 21. As with
