High magnification SEM image of open cell polyurethane foam
If a gas is injected into a liquid it forms a cellular foam structure. When a thermoset prepolymer of low viscosity is foamed, the polymer can drain from the cell walls (driven by surface tension) before it sets at the cell edges, leaving an open-celled foam. The cell edges have three concave sides, and some remnants of collapsed cell walls can be seen at the cell edges.
Author(s): DoITPoMS, University of Cambridge,J A Curran, Depa

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2.7 Geological problems in coal mines

A modern coalface is a very complex operation that represents a large investment in terms of capital, labour and planning. Cutting machines and lengthy conveyors are inflexible and require uniform geological conditions to maximize output. What then are the effects of geological variations on such a mining system?

Geological factors control the selection of working areas. The two principal geological conditions that affect mining operations are, first, the nature of the coal-bearing rock
Author(s): The Open University

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Conclusion

This free course provided an introduction to studying Mathematics. It took you through a series of exercises designed to develop your approach to study and learning at a distance and helped to improve your confidence as an independent learner.


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5 Conclusion

Domesticated organisms evolve in artificial environments under artificial selection, and opportunistic or enforced hybridisation often occurs between species that would not normally interbreed. Natural selection cannot be eliminated and continues to operate. At least two different forms of dwarfism are common in domesticated livestock and humans, but only the rarer midget type of dwarfism occurs in wild lineages. Domesticated mammals and birds have distinctive patterns of skin pigmentation th
Author(s): The Open University

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6.5 Summary of Section 6

Growth cones respond to proximal and distal cues. The proximal cues in the extracellular matrix or other cells affect adhesion and result in chemotactic guidance. Distal cues are also in the extracellular matrix but they diffuse through it and result in the growth cone either moving towards the source (attractants) or away from it (repellants). These distal cues are chemotropic cues and can have different effects on different growth cones; what may be an attractant to one growth cone may be r
Author(s): The Open University

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Native American Portraits
This is a video of portraits of the famous Native Americans of history: Powhatan, Pontiac, Tecumsah, Sequoiya, Sitting Bull, Red Cloud, Crazy Horse, Geronimo, Joseph, Jack, and others. However, the people are not identified. Music is "Mountain" Apache Song & Drogo's Pan Ethnic Quintet. (02:20)
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The Writing Process: You Can't Write Well Without It PowerPoint
This PowerPoint presentation is a review of the steps in the writing process.  It talks about prewriting, brainstorming, outlining, drafting, word choices, revising, proofing, and presenting.  This video itself is quite simple, but the information presented is very thorough.
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4.7 Build prototype/demonstrator

The physical models we talked about earlier are prototypes or demonstrators of a sort. However, for the purposes of making a clear distinction in the process, I'm referring here to prototypes or demonstrators as functioning preliminary models of the essential finished product or construction or service, bringing together all the elements of the design that may or may not have been previously physically tested (Author(s): The Open University

Up Close: Casey Coffman
The Senior Vice President, Corporate Strategy and Development for The Madison Square Garden Company discusses how sport and entertainment are closely knit, her leadership style, and her vision of how technology will influence the future of sport.

5.1 Introduction to key concepts

Before I go any further I will establish the meaning of some of the key concepts that you will encounter throughout this unit.

The key concepts elaborated in this unit are:

  • inventor

  • invention

  • design

  • product champion

  • entrepreneur

  • improver

  • innovation

  • dominant design

  • robust design

  • lean design

  • radical
    Author(s): The Open University

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5 How might dialogue move on from GM Nation?

There is a widespread optimism that ‘lessons have been learnt from the GM Nation? Debate’ – indeed the government's response to the exercise was couched in just those terms (DEFRA, 2004). One concern has been touched on already – many felt that the debate took place too late, on a rushed timetable, at a time in the controversy when the debate had become highly polarised and divisive ‘pro’ or ‘anti’ stances already embedded. This late in the day, questions for public discussion
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7 Final thoughts

We deliberately chose a wide range of different initiatives to explore, to reflect the broad range of initiatives underway. And yet, as you have seen, there are common threads that run though all our examples, such as the representativeness of ‘public’ opinion and how outcomes input into policy making. A key issue that Reading 5 highlighted was
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7.6 Questions

Question 15

Suppose that a galaxy has emission lines in its optical spectrum. A line of wavelength 654.3 nm is broadened by 2.0 nm. Estimate the velocity dispersion of the gas giving rise to the broadened spectral line
Author(s): The Open University

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2.3 IT and you

Sometimes it's useful to stop and think a bit about your own experiences and focus on your own views. This can help you understand issues in more depth. For example, when studying the impact of IT on everyday life, your own experiences are a useful resource.

Activity 4

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5 ‘Indian’ on the outside

In 1801 and 1805, first Holland and then his assistant William Porden (1775–1822) had been commissioned to make sketches for altering the exterior to a Chinese style so as to match the extravagantly Chinese interiors, but these projects remained unfulfilled ( Plate 14 ). Drawing on the pictorial records brought back by William Alexander f
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Writing Responses to Open-Ended Questions
This is a presentation of 16 slides that addresses how to answer open-response questions. View at your own pace.
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#380: Recovery from stroke: Harnessing the brain's capacity to overcome disability

Stroke rehabilitation researcher Prof. Julie Bernhardt discusses the state of the science in stroke recovery. Taking an interdisciplinary approach, Prof Bernhardt and her team develop and test new exercises and rehabilitation measures that aim not only to reduce disability but promote recovery. This includes renewed attention to precise timing
Author(s): up-close@unimelb.edu.au (University of Melbourne)

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Rights not set

2.2.2 Energy and conservation

Newtonian mechanics is concerned with explaining motion, yet it contains within it the much simpler idea that some things never change. Take the concept of mass, for example, which appears throughout Newtonian mechanics, including the law of gravitation. In Newtonian mechanics, mass is conserved. This means that the mass of the Universe is constant and the mass of any specified collection of particles is constant, no matter how much rearrangement occurs within the system. A chemist might take
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3.6 Different paradigms and different methods

These different methods alert us to the fact that psychology is not just one enterprise, but a series of interlocking enterprises in which psychologists have different views about the best ways to try to understand or explain people and their behaviour and experience. These are arguments about epistemology; that is, what questions to ask, what sort of evidence to look for, what sort of criteria to use to evaluate explanations, and what sort of methods to use.

All knowledge and al
Author(s): The Open University

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