5.6 Filtration In filtration, the partially treated water is passed through a medium such as sand or anthracite, which acts as a ‘strainer’, retaining the fine organic and inorganic material and allowing clean water through. The action of filters is complex and in some types of filter biological action also takes place. Sand filters are used in water treatment to remove the fine particles which cannot be economically removed by sedimentation. They have been effective in removing Cryptosporidium,
2.7 Infiltration Entry of precipitation through the soil surface and on downwards, by gravity, is known as infiltration. The rate at which this process can take place is governed by the permeability (a measure of the ease with which water can flow through the subsurface layer) and by the existing degree of saturation of the soil. Infiltration can be impeded by outcropping impermeable rocks or by paved areas, and also by the presence of finegrained soils with a low permeability (such as clay). At certain times
Learning outcomes After studying this unit you should be able to: describe the operation and mechanisms of the hydrological cycle; list and describe the major physical, chemical and biological characteristics of clean fresh water, and explain their effects on aquatic organisms; explain the mode by which potable water is produced through the processes of screening, microstraining, aeration, coagulation and flocculation, sedimentation, flotation, filtration and disinf
3.3.2 Planning the investigation A plan was needed to determine the chain of events leading up to and during the collapse. That sequence would necessarily depend on which parts had broken first, and a fault tree would enable a plan of action in isolating the cause (or causes) of the disaster. Such a systematic approach is known as fault-tree analysis or FTA, and is part of the armoury of methods used by accident investigators. With large-scale and devastating accidents, all possibilities, however remote, need evaluation in t
Acknowledgements This unit was written by Ms Candida Clark The content acknowledged below is Proprietary (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 mater
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:
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7.5 Religion: a ‘good’ thing or a ‘bad’ thing? In considering the value of religions, we can begin by saying that one of the first tasks of the critical student should certainly be to test the basis of judgements offered by other commentators. We saw earlier that the Church of Scientology has had problems gaining official recognition as a ‘relig
7.4 Religion: true or false? I noted earlier that differences between the truth claims made by religions has led those who practise Religious Studies to avoid premature judgements when dealing with questions relating to the truth and value of particular religions. By seeming to by-pass truth claims, you may feel that what I have been describing as Religious Studies avoids what many would regard as the purpose of religion – to deal in truths. This is a difficult area to cover briefly, but let me at least try to explain
7.1 Some basic principles of religious studies Remember that in Section 4 I suggested that possible reasons for studying religion could be clustered together under two broad headings: to understand the society in which we live, the culture we inherit and the wider world of which we are a part; as part of a personal quest for religious
5.3 Scholarly definitions of religion Scholars offer us many different definitions of religion, but these definitions tend to be of two types. The first type is known as a substantive definition: that is, a definition that tells us what kind of thing religion is by pointing to its distinguishing characteristic – usually its beliefs and/or practices. We can find an example of a substantive definition of religion in my summary of the definitions found in the Concise Oxford Dictionary. Think again about d. Acc
5.1 ‘Religion’ and ‘the religions’: two new notions I want to begin our closer discussion of the question ‘what is religion?’ by looking briefly at the history of the use and meaning of the term. You may be surprised to find how recently the word ‘religion’ has taken on the meanings attached to it today. Contemporary scholars of religion emphasise not merely the cultural breadth but also the antiquity of religious activity. Yet, the term ‘religion’ as we understand it today is very much a Western concept. 4.4 Religion and social policy Understanding religious beliefs and practices and what we mean by ‘religion’ is not merely of academic interest. It is often bound up with social policy and so relates to the rights and privileges of individuals. In Britain, for example, the Church of Scientology has not been allowed to register i 4.1 The impact of A Practical View
A Practical View is significant both as a kind of ‘manifesto’ by a prominent figure in a religious movement of rapidly expanding influence, and as part of an ongoing process of reflection on the state of British politics and society in the aftermath of the French Revolution. Wilberforce had been working on it intermittently for four years before its eventual publication on 12 April 1797. As a busy politician he struggled to find the time for sustained writing. He had initially had 2 Britain and the French Revolution In Reflections on the Revolution in France (1790) Edmund Burke (1729–97) made clear his hostile reaction to the Revolution, which he perceived as a dangerous destruction of tradition and continuity in favour of abstract Enlightenment principles. On the other hand, there was a substantial cross-section of British opinion that initially warmly welcomed the Revolution, including Wilberforce himself, as well as much more radical individuals, such as Thomas Paine (1737–1809). Init 5.4 Assessing Hume's views The main value of Hume's essay lies in its discussion of our duties to God. Here Hume's arguments initially seem quite convincing. But arguments almost always seem convincing when they are first heard and understood. The real test comes when we try to think of possible objections. Here is one such objection, based on what has become known as the problem of evil, the problem of reconciling God's benevolence and omnipotence with the fact that evil exists in the world: 1 Prelude: Hume's death In mid-August 1776 crowds formed outside the family home of David Hume. Hume was a pivotal figure in the Scottish Enlightenment, and his imminent death was widely anticipated. The crowds were anxious to know how he was facing up to his coming demise. Hume is best known today as a historian (through his History of England of 1754–62) and a philosopher. His Treatise of Human Nature is regarded by many as one of the most significant philosophical works to have been written 3.3 The divide over the Church, 1790 The revolutionaries of 1789 also aspired to reform the Catholic Church in France, though not to disestablish it, still less to de-Christianise the country. Many of the clergy themselves favoured reform. In August 1789 the Assembly deprived the Church of its income by abolishing the tithe. In November it decreed the sequestration (nationalisation) of church lands, roughly 10 per cent of all land in France, for public sale. The Assembly was prompted by the same need to raise revenue to pay off 5 Further reading Stevenson (2003) is a good place to start in clarifying the various conceptions of imagination, but for a fuller exploration, analysing in detail the language of imagination both historically and conceptually, although with many questionable claims, White (1990) can be recommended. Of the other books mentioned in this chapter, Brann (1991) is a superb resource of ideas on the imagination throughout history and in all areas of intellectual life, and Johnson (1987) makes a strong plea for a ‘ 3.2 Imagination and supposition To regard images as playing an essential role in imagining is to conceive of imagination as a sensory power. But as we have seen, imagining can also occur in the absence of imagery, and we might take this to reveal a more intellectual form of imagination. Many philosophers have suggested that this more intellectual form of imagining be construed as supposing. On this view, to imagine something, in cases where there may be no imagery involved, is to suppose something. But is it right to Acknowledgements This unit was written by Dr Derek Matravers
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