References Glossary Click on the link below to open the unit glossary. 3.3 Estimating your personal ecological footprint In this activity the aim is to begin to engage in mathematical modelling by quantifying your ecological impact. The transition between qualitative quality of life indicators and quantitative ecological footprinting also requires a shift from visual and verbal modelling to mathematical model 3.2 Exploring your quality of life In this activity the aim is to develop and use a range of interdisciplinary indicators that describe your quality of life. 3.1 Exploring your personal ecology One of the simplest techniques one can use when investigating a complex situation using a systems approach is to jump between organisational, spatial and temporal scales and explore the relationships between these scales. In this activity the aim is to develop a Author(s): 2.4 Limits to growth In April 1968 a group of thirty people from ten countries gathered in Rome. From this meeting grew the ‘Club of Rome’, a loose association of people of twenty-five nationalities all united by their belief that mankind faced major problems which were of such complexity that traditional institutions and policies were not capable of dealing with them. They commissioned a study which was eventually published in 1972 entitled The Limits to Growth (Meadows et al., 1972). This initiative 2.3 Threats to the living planet An idea, a relationship, can go extinct, just like an animal or plant. The idea in this case is ‘nature’, the separate and wild province, the world apart from man to which he adapted, under whose rules he was born and die 4.3 Chain growth polymerization Chain growth polymerization is basically a three-stage process, involving initiation of active molecules, their propagation and termination of the active chain ends. 3.3.1 Ethylene, propylene and butadiene Nowadays ethylene is the most important building block for the chemical industry, particularly as a monomer in its own right, as a co-monomer with other vinyls, and as a source of vinyl monomers. It is the prime source for ethylene oxide, which is another major source of polymers, glycols and ethers. They can also be used to build up more complex C4 molecules and aromatics. Some of the ways in which the ethylene molecule is modified to create other chemicals and polymers are 2.7 Commercial polymers The increasing control of polymer structure by fine-tuned catalysis of polymerization opened up an enormous area for commercial exploitation, and new polymers are still being produced in this way (such as the metallocene polymers). A revolution of equal magnitude has occurred with polymers containing functional groups, for example, the nylons, polyesters and polyurethanes, resulting in polymers ranging from quite simple structures like aramid fibre to relatively complex repeat units like thos 2.6 Molecular mass distribution 2.3.4 Stereoisomerism A final type of isomeric variation occurs as a result of the three-dimensional structure of some polymers. It is possible because a four-valent atom like carbon can exist in two different forms when the subsidiary groups or atoms attached to the carbon are all different. The carbon atom is then known as an asymmetric carbon atom. A very simple example of the phenomenon is the structure of a small molecule, lactic acid. As Figure 20 shows, it can exist in two forms which are mirr 3.1 The steps to systems modelling Systems modelling in practice usually involves six broad steps, within each of which there may be many subsidiary steps and some checking and revision. There is also likely to be iteration back to the earlier steps, as issues which call for changes in earlier decisions are uncovered. Nevertheless, in my experience, the following six steps are likely to cover the basics. Identify the system of interest, in particular specify the system boundary a 4.4.2 Passive optical networks and Ethernet in the first mile If FTTH uses a dedicated fibre link between each house and the telephone exchange then each house carries the cost of two sets of terminal equipment: one in the house and one in the exchange. A significant saving can be made with the passive optical network (PON) configuration (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. Learning outcomes By the end of this unit you should be able to: discuss what ethics is and what constitutes an ethical issue; identify and discuss ethical issues that arise in the media, in routine conversations and, in particular, in your own everyday professional practice; discuss the role of emotions in ethical deliberations; discuss how negotiation might resolve apparent ethical differences; identify and discuss the ethical issues p 6.5 Costs 11. What are the financial costs involved (capital and recurring)? 12. What additional non-financial resources will be needed? 13. When are the all the various financial and non-financial resources needed? 8.4.1 Open-loop control Open-loop is the crudest way of controlling etch depth. It relies on ensuring that every aspect of the process that can affect the rate of progress of the etch is kept under tight control. This can add up to a sizeable list. Table 5 shows just some parameters that affect both wet and dry etching. Whether 7.3.3 Plasmas More control can be achieved in vapour deposition if a plasma is generated. A plasma is simply a gas where a proportion of the molecules have been ionised. The ions remain in an uneasy equilibrium with the electrons they have released, prevented from recombining only because the electrons are hot and fast-moving, and so are difficult to trap. Plasmas are widely used in materials processing, with pressure ranging from 10−3 mbar to 1 mbar and typically up to 1% of the molecul 4.3 PZT The above requirements lead us to a range of ceramic materials with crystalline structure. One such material is lead zirconate titanate (PZT), which is an oxide alloy of lead, zirconium and titanium. It is often used in a specific composition (sometimes with additives) in order to achieve a particular crystal structure and the desired piezoelectric response. Author(s):
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Alexander, G. (2002) eGaia: Growing a Peaceful, Sustainable Earth through Communications, Florida, Lighthouse Books.
Allinson, C.W. and Hayes, J. (1996) ‘The cognitive style index: a measure of intuition-analysis for org
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