8.2 Wet etches: acids and bases The simplest etches use a liquid solvent that converts the material into a soluble compound or a gas. Unfortunately, most materials used in micro-devices have few soluble compounds, so some very aggressive chemicals are needed to attack them. Here is a list of some of the most commonly used ones: Hydrofluoric acid (chemical formula HF) is used to convert silicon dioxide into water-soluble H2SiF6 (plus some hydrogen and water). It
7.4.7 Deposition of patterned films: lift-off and damascene We have assumed throughout this section that the deposited film will cover the entire wafer surface and that its patterning will be performed by subsequent lithography and etching steps. However, some materials, most notably copper, can be very difficult to remove with micrometre-scale precision or better, making this sequence extremely difficult. Since copper, with its high electrical conductivity and good chemical properties, is increasingly used in microelectronic device fabrication, anoth
3 Sound production in musical instruments Musical instruments come in all shapes and sizes and produce an enormous variety of different sounds. Yet, with the exception of certain electronic instruments, the basic physical principles by which sound is produced are the same for all instruments – including the human voice. In this section, I shall introduce some of these principles. These will then be expanded upon over the rest of the unit. Remember I told you that when a musician plays an instrument they cause it to vibrate. T
10.9.1 New materials The discovery of new materials, exploration of their properties and the invention of new industrial processes is a huge field of study in its own right. The potential rewards for a company discovering a successful application of a new material are great. An example of this is shape memory alloys (SMAs). SMAs are mixtures of metals that, after being stress treated, can be deformed significantly but then triggered to return to their original shape. Some display unusual elastic properties
10.6 What drives invention in organisations? Much invention and nearly all innovation nowadays take place inside organisations – from small start-up companies to well-established multinationals. This is mainly because increasingly invention and innovation require access to technology and resources beyond the scope of most individuals. But it is also because competitiveness and survival depend on the continual improvement of a company's products and processes. This provides a strong incentive for companies to invest in both the increme
10.5 Desire to help others This is a less common motivation but it shows not everyone is driven by money. In 1991 the inventor Trevor Baylis saw a BBC documentary about the spread of HIV/AIDS in Africa. What was needed was a way of broadcasting the safe-sex message to people in areas without electricity and where batteries for a radio could cost a month's wages. Solar power wouldn't necessarily help as most people who could get to a radio listened in the evening after work. While absorbing this information he ima
5.14.3 Electrodialysis Electrodialysis is an electrochemical process in which ion transfer separates salt from water. It is effective only for substances that can be ionized: for example, salt (NaCl) becomes, in solution, a mixture of Na+ and Cl− ions. (Silica, on the other hand, does not ionize and hence is not removed by electrodialysis. It could, however, be removed by reverse osmosis.) When electrodes, connected to a suitable direct current supply, are immersed in a salt solution, curren
8.8 Hinduism as ‘a world religion’: a more recent understanding Traditionally, as we have seen, a Hindu was someone born to Hindu parents and into a caste with its appropriate dharma. The link between religious practice and a whole way of life bound the individual into a community from birth. Regional factors, parentage and caste affiliation largely determi
6.3 Setting things apart The tendency within religious behaviour to set things apart from the everyday does not just apply to time and place but also to ideas of authority (leaders and texts), to beliefs more generally, to institutions and to aspects of behaviour as, for example, in dress and diet. In fact, the concept of ‘religion/religious’ is often set over and against the concept of the ‘temporal’ and the ‘secular’, which both suggest an outlook that is concerned solely with this world, the here and n
Introduction This unit introduces key questions about language and thought, such as how can language, which is public and accessible, be used to convey thoughts, which seem hidden from view. This unit is an adapted extract from the Open University course Thought and experience: themes in the philosophy of mind (AA308).
Further reading General introductions to the philosophy of mind tend to be ahistorical and vary greatly in accessibility and coverage. E.J. Lowe covers virtually the whole range of topics in his An Introduction to the Philosophy of Mind (2000). For less coverage but more detail see Jaegwon Kim's slightly more advanced but excellent Philosophy of Mind (1996). Tim Crane's The Elements of Mind (2001) is another very good but more advanced introduction to current issues and contains one of t
6.4 Second Essay As a preliminary to the Second Essay, Owen says that he will enhance further his discussion of his underlying principles and then begin to explain to his readers how they can be applied in practice. Notice too the prologue for the Second Essay (p. 113) , quoting Vansittart's view that ‘if we cannot reconcile, all opinions, let us endeavour to unite all hearts’, a ringing phrase often quoted by Owen in later publications and widely adopted as one of the most popular Owenite homilies
1.1 Introduction An interesting analysis of Napoleon's involvement in Spain is provided by Stendhal in A Life of Napoleon, chapters 36 to 43. Stendhal argues that Napoleon's basic error was to see Spain as susceptible to the imposition by the French of the kind of enlightened reforms which had been welcomed elsewhere in Europe. Stendhal particularises, in a way characteristic of Romantic writers, on what he considers a highly distinctive Spanish national character, which in his view explains the hostil
5 The characteristics of ‘good’ information Have you ever seen a set of published accounts for a company? If you haven’t or, even if you have, take a look at some now. (They are often called the annual report.) Internet activities are intended to show you the large range of information available at your fingertips. Some of it is useful, most of it is not. Accountants are increasingly having to deal with growing quantities of information and many are having to search for relevant information as part of their jobs. These I
Introduction This unit is from our archive and it is an adapted extract from The professional certificate in management (B615) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer in this curriculum area. In this session we look at the first stage of managing people – attracting and selecting
Activity 1: What is working life? Allow about 35 minutes for this activity. As you saw from the introduction above , your work is central to the learning you will gain from studying BU130. In our view though, ‘work’ does not mean the same as ‘paid employment in an organisation’. The idea that these two things are the same is an assumption that is made in many areas of life, such as management courses, careers advice and newspaper reports. It is certainly true that very many of us earn our living thr
Learning outcomes Work, of course, does not just mean the work you do when you are employed by an organisation. Many people are self-employed, do voluntary work or work to care for others in unpaid roles. You will read more about this broader definition of work below. There may also be a number of reasons why you would want to use this module to improve your working life. You might, for example, want to: improve your work performance enhance your promotion chances c
Introduction This extract from BU130 Working and learning: developing effective performance at work is taken from the introductory week of this module. In it, you will be asked to identify areas in which you would like to improve your performance at work and to think about how you might carry out projects in the workplace to learn how to achieve this improvement. If you choose to go on to study this module you will spend the first eleven weeks planning these projects (which we call work-based learning in
1 Understanding operations management Consider the ingredients of your breakfast this morning. Unless you live on a farm and produced them yourself, they passed through a number of different processing steps between the farmer and your table and were handled by several different organisations. Similarly, your morning newspaper was created and delivered to you through the interactions of a number of different organisations. Every day, you use a multitude of physical objects and a variety of services. Most of the physical obj
1.5 Matrices A matrix is an arrangement of ‘cells’ in rows and columns. A spreadsheet is a simple example of a matrix. Each cell is described by its position in a column, normally denoted by an alphabetical letter, and in a row, normally denoted by a number. So ‘cell B6’ on your spreadsheet is the one which occupies column B and row 6. The size of a matrix is described by the number of rows and the number of columns (in that order). A ‘two-by-two’ matrix has two rows and two columns. A â
