Now back to forces for change. Figure 11.7 is the road map for this section and the next. The central spine represents the design or redesign process, moving from market need through the steps of development (including choice of material and process) to the specification and ultimate production of products. The radial boxes summarize, on […]
Category: Materials and the Environment: Eco-Informed Material Choice
Carbon, energy, and GDP
The greater number of people who use a resource, the faster it is depleted. Global population—symbol P—is rising, and so too is affluence, which we will write as gross domestic product (GDP) per capita, GDP/P. Then material consumption grows as The last term is the material intensity of GDP. Energy consumption can be expanded in […]
Material value
How is it that materials are seen as of such little value? The waste stream is now so great that densely populated countries are running out of space to store it. We recycle some, but only under duress; it takes legislation, subsidies, and taxes to make us do it. Gold doesn’t get thrown away; its […]
The bigger picture: future options
11.1 Introduction and synopsis In drafting the first 11 chapters of this book I have felt, more than once, that I was describing ways to fix a leak in the ceiling while ignoring the flood waters rising through the floor. It’s time to look at the bigger picture, and it is not an entirely happy […]
Sustainable materials
No matter how you look at it, using materials costs energy. Let us put that fact aside and examine the degree to which the materials themselves are sustainable. To be so, a material must be drawn from a source that is renewable, either because it grows as fast as we use it or because it […]
Sustainable energy
With enough cheap, nonpolluting energy, all things are possible. The average power needs of a developed country today range from 4-14 kW per person, which translates into an energy consumption of 120-450 GJ/year per person.[41] This energy is used in the ways listed in Table 10.1. The transport sector is more dependent than the others […]
The ecological metaphor
The ecological metaphor has its genesis in the observation that natural and industrial systems have certain features in common. Consider three: 1. Both the natural and the industrial systems transform resources— materials and energy—that of nature through growth, that of industry through manufacture. The plant kingdom captures energy from the sun, carbon dioxide from the […]
The concept of sustainable development
As engineers and scientists it is natural that we should want to tackle problems at a level to which we can bring our skills to bear. The methods described in the previous chapters are examples. They address immediate problems, ones that are already evident and identified. But they do little to tackle the deeper problem: […]
(a) stiffness and strength
Calladine, C. R. (1983), "Theory of shell structures", Cambridge University Press. ISBN 0-521-36945-2 Young, W. C. (1989), "Roark’s formulas for stress and strain", 6th ed, McGraw-Hill. ISBN 0-07-072541-1. (A “yellow pages" for results for calculations of stress and strain in loaded components.) Solutions to standard problems: (b) heat flow Hollman, J. P. (1981), "Heat transfer", […]
Transport
Transport accounts for 32% of the energy we use and 34% of the emissions we generate (Figure 2.4). Cars contribute a large part of both. The primary eco-objective in car design is to provide transport at minimum environmental impact, which we will measure here by the CO2 rating in grams per kilometer (g/km). The audits […]