Sustainable Architecture and Design

Sustainable Architecture and Design Sustainable, eco-friendly architecture can often be seen as the radical hippy of neo-liberal architectural discourse, with its practical application in the 21st century limited and problematic. Is there space for the synergy of idea in this regard, producing usable and practical or whimsical and gracious buildings that also adhere to the classical ideas of beauty and proportion? Sustainable[1] and eco-friendly architectures[2] were the subject of much left of centre discourse throughout the 1960’s and 1970’s against the backdrop of late Modernism and the initiation of constructed, clean post–Modernity. They were in opposition to the shock of the ‘new’ the marvels of concrete and structural steel and the innovations that supported closed environments such as elevators and air-conditioning. The seemingly ‘hippy’ applications of buildings that suited the environment, responded to them, and trod lightly in their space appeared irreconcilable in the context of the masculine, rational and spare elements of Modernity. The fear that beauty[3] could not exist in a mixed relationship, that a building could be both environmentally friendly and be visually appealing was not always an option in the hegemony of late modernism. However, this paper discusses the synergies that arose from these apparently oppositional ideas. The modernist era of tower blocks and buildings that fitted in with the ‘form follows function’ premise, ignored the possibilities of working with the environment and also being informed by it. The post-War building boom was expeditious, masculine and prolific, with the modular systems of the International Style informing all of the above. The shock of the new, invention and innovation left little space for the architectures engaging with the environment or the vernacular textures. Issues of sustainability were very much part of a neo-liberal brief, and disregarded by the world order of the time who had not yet woken up to the issues regarding the depleted ozone layer and greenhouse gas emissions. However, occasionally, there was minor dissent, particularly in the British colonies, where the imposed architecture of the colonist had been, to some extent environmentally adapted by the settlers using vernacular materials and adapting some elements of the indigenous building systems that they found there. Throughout this, though, the prevailing post-War building idiom of the mother country was largely retained, adaptability being one of the successes of Modernism. Those careful and socially conscious architects that contested the climatically and culturally inappropriate imposition of modernism strove to combine old and new materials and old and new technologies to create regionally appropriate buildings that were a vernacular in their own right and yet a new architecture that combined all the radical notions popular in the hippy culture of the late 1960’s. Norman Eaton, a South African, was cognizant of environment and reduction of the air-conditioning loads when he designed his Netherlands Bank Building (1965) in Durban, South Africa, a five level building where the building stands on a white marble podium and forms a pavilion in the centre of the high-rise urban fabric. The external curtain wall is replaced by a brise-soliel of green ceramic hollow clay blocks forming a massive sunscreen and significantly reducing the air conditioning loads in a hot, humid climate. ‘The unbroken expanses of ceramic screening were the result of Eaton’s approach to the challenge of Durban’s heat and were not employed for aesthetic effect alone. The open and yet cool aspect of the interior and the considerably reduced load on the building’s air conditioning system testify to the screens functional success. Behind the screen and invisible from the outside a second curtain wall, this time of glass, also covers the building, so that all internal levels are well lit but at the same time well protected against the glare and heat of direct sunlight.’ (Haropp-Allin; 1975: 107) Visually, although the building is a regionalist adaptation of what was a prevailing modernist format, the building and its incorporated garden spaces provides cool relief and a refuge in a hard edged landscape.[4] Almost two decades later, the Australian John Andrews in his Eugowra Farmhouse, New South Wales, (1979) maximized the orientation of the building such that he combined the use of prevailing winds for cooling in the Australian outback together with a central fireplace for heating. A prominent rainwater tower in the centre of the roof is both a strong vertical element, creating ‘architecture’ and at the same time harvesting water which is a critical necessity in the arid environment. This element is also able to spray water onto the roof for cooling in extreme weather. This was all combined using modern materials in a vernacular idiom combined with a classical symmetry, producing a gracious neo-outback veranda house. With these examples quoted above, a strong sense of regionalism is implicit in the sustainability and the environmental generators that form the ‘natural’ brief. For a building to be modern, beautiful and environmentally sustainable, it follows that the structure should be in a regionalist ‘idiom’ using modern materials housing modern facilities, with the incorporation of some of the vernacular, as the meaning of the site and the climate is by definition a regionalist issue. It was not only in the antipodean regions that this critical discourse was occurring. From the beginning of the 1960s, a number of papers and publications supporting the architecture of the vernacular and its many manifestations, connecting this to environment, culture and landscape, spawned the radical publications such as ‘Shelter’ (1973) which explored the notions of building using traditional materials, textures and forms, and adding to this sustainable methods of drainage, rainwater capture, foundation formation and environmentally friendly methods of heating and cooling. This treatise however was aimed at people pursuing more of an alternative lifestyle, using the landscape and other culture’s building methods to house them in an ecologically sustainable fashion. More conventional publications such as the work of Fitch in 1960, and the works of Rudofsky (1965) and Rapaport (1969) explored the connections between climate, landscape and culture. They investiga ted the traditional means by which building were constructed to address all the social and climatic constraints that produce sustainable buildings that tread lightly on the landscape and do not need large amounts of extra resources such as heating, cooling, and electricity consumption. These publications were still way left of the conservative centre, and not embraced by the rapidly mechanized northern countries. Few architects in the formal sector were prepared to stick their necks out in this regard, leaving the alternative housing solutions to those that pursued alternative lifestyles. A marked example does, however, stand out- Paolo Solieri, a student of Frank Lloyd Wright conceived of his Arcosanti Project in 1970, where some 70 miles north of Phoenix, Arizona, a compact complex hoping to eventually house some 5000 people is designed in a way such that the outside arable land is maximized, the living areas are condensed providing ready access to open desert for all dwellers, an d a number of large greenhouses provide food for the inhabitants. These structures also act as solar collectors for winter heat. Solieri’s aim was to design an urban environment that would function in a manner providing the maximum social, economic and health benefits, as well as treading lightly on the landscape on which it sits minimizing the effects on the earth. His principle of ‘arcology which married the ideas of ecology and architecture is described below. In nature, as an organism evolves it increases in complexity and it also becomes a more compact or miniaturized system. Similarly a city should function as a living system. It must follow the same process of process of complexification and miniaturisation to become a more lively container for the social, cultural and spiritual evolution of humankind. The central concept around which these developments revolve is that of arcology- architecture and ecology as one integral process. Arcology is capable, at least theoretically, of demonstrating positive response to the many problems of urban civilization, population, pollution, energy and natural resource depletion, food scarcity and quality of life. Arcology is the methodology that recognizes the necessity of the radical reorganization of the sprawling urban landscape into dense, integrated, three- dimensional cities in order to support the complex activities that sustain human culture. The city is the necessary instrument for the evolut ion of humankind. Paolo Soleri (Arcosanti Workshops 2000 pamphlet) The Cosanti-Arcosanti pamphlet notes that Newsweek commented that ‘As urban architecture, Arcosanti is probably the most important urban experiment undertaken in our lifetime’ (Cosanti-Arcosanti pamphlet; 2000) However, despite this accolade by the popular, ‘thinking’ press, the project, nearly four decades later, struggles along still in the construction process, and is more of a site for those people that pursue the alternative than people living mainstream, corporate lifestyles. As a site it is a museum, a school, a point of pilgrimage. For very few people, it is a lifestyle. Bringing these combined issues of ecological, social and economic sustainability, to the forefront, making them trendy and implicit, has been the largest challenge to the production of sustainable architectures. The realisation that the construction industry and the operation of the buildings that it makes, as Hyatt quotes (himself and) Edwards (Hyett in Abley Heartfield;2001:30) ma kes it ‘responsible for 50% of ‘all energy resources consumed across the planet, making the construction industry ‘the least sustainable industry in the world’. This fact has taken a while to entrench itself in ‘first world’ industry. Issues of sustainability and appropriate technology are not new- as mentioned earlier they formed the basis of developmental jargon in the ‘Third’ World. Sustainability in architecture as a technical approach in the management of particular resources has been the subject of discussions in the last three decades, with the 1975 ‘Alternatives to Growth’ conference which expanded the definition realizing the limits of a static- state economy: this time sustainability fell within the realms of the economists and not the built environment practitioners. Then, the issue of the control of technology by the Northern Hemisphere was dealt with by Willy Brandt who, in 1980, led the Independent Commission on International Development Issues, producing a report headed ‘North- South- A Programme for Survival’. (Heartfield in Abley Heartfield; 2001:97) Here, the connections between sustainable development and appropriate technology were made, entrenching the i dea of appropriate technology in a developing country context. This was almost fatal, as Heartfield notes ‘What appropriate technology meant for the less developed world was the lowering of expectations; less capital input, less expenditure, less technology.’ (Ibid;97) Perhaps this perceived ‘lower’ level of existence is one of the reasons why the plea for incorporation of these ideas of sustainability in the northern hemisphere fell largely on deaf ears. ‘It could be said that sustainability is a fudge. It raises all the same presuppositions of the limits to growth thesis, that absolute resource limits are upon us, but avoids their implied conclusion, a moratorium on growth. What the concept of sustainability preserves of the ideology of limits is the sentiment of constraint and parsimony.’ (Ibid;97) Finally, the Bruntland Report [5] submitted in 1987 is seen by Heartfield as being credited with the ‘popularizing of the concept of sustai nable development.’ (Ibid:96). However, although this may have made the concept more digestible, it did little for popularizing its practice, for, as the Bruntland Report, quoted in Heartfield states- ‘Sustainable development requires that those who are more affluent adopt lifestyles within the planet’s ecological means’.(Ibid:97) Despite this so called acceptance, a much later technical work in a somewhat a pleading tone, by Crowther notes that ‘The ecologic responsibility is to ourselves and the global legacy of human habitation. Every choice made from concept, to design, to realization is a demand that results in ecologic and biologic consequence.’ (Crowther;1992:vii) However, the throwing of these twentieth century gauntlets such as that by Crowther has received results in latter years. Prototypical examples as that presented by Pearson in his Gaia House (Pearson;1989:40-41) may have influenced some of the challenges to be presented; the principles in his charter declare ‘Design for harmony with the planet, Design for peace for the spirit, and Design for the health of the body. The first instruction involves the use of ‘green materials’ that have as embedded qualities ‘low environmental and social costs’, which are ultimately bio-degradable and can be or are recycled. Together with this the importance of correct orientation, the use of all the elements for energy including wind, recycling grey water and collecting rain water all add to the minimized impact on the soil. Pearson also mentions the need to maximize the efficiency of the natural spaces by planting indigenous trees and flowers. (Pearson;1989:40) It was only recently, with the building explosion on the Pacific Rim, and the attacks on the World Trade Centre, that the northern hemisphere began to seriously address these issues of sustainable construction, particularly in the densely populated cities of Europe. In October 2001, the Royal Institute of British Architects (RIBA), hosted a conference that was to address the issues of creating environments that addressed issues of sustainability. This conference, ‘Sustainability at the cutting edge’, ‘was to provide an overview of the science and technology behind sources of renewable energy which would assume prominence in the next decade. This review was placed in the context of increasing concern about the impact of climate change and the fact that the built environment in countries like the UK is the worst culprit in terms of carbon dioxide emissions.’ (Smith,2003;xi) This quotation, from Smith’s technical work, emerged from this gathering. More of a handbook, it examines environmentally sensitive options for heating and cooling, and offering the option for drastically reducing emissions in urban buildings in an environment that (now) tacitly accepts the need for ecological architecture. A number of approaches which demonstrate the sensitive manipulation of all elements of the brief to create an ecologically sound, a culturally sensitive, a socially appropriate and an economically viable building have come to light, many of which employ much of Pearson’s First Principle as mentioned above.[6] The examples fulfill a variety of scales of development, and different intensities in terms of sustainability with regards to site. On the one hand, it is sadly disasters that prompt new innovative methods of shelter, in a modular though aesthetic form. Out of the Hurricane Katrina catastrophe came the Modular Transitional Growth Housing (MTGH)[7] a conceptual system that consists of a number of elegant forms which can be bunched together in a variety of forms and combinations to shelter, recycle, light and cool. Architect Philippe Barriere introduces a BioClimatic design element with high ceilings and naturally stimulated ventilation which assists in the above. However, this highly conceptual modular structure is on the knife edge of socially practical and Marxist zeal- seen as an approach that can solve a multitude of housing problems from disaster relief to inner city complexes to fishing retreats, the reality of its implementation is as conceptually choppy as Arcosanti- mass appeal is visual but not implicit. A more practical and tangible solution to a mass housing challenge is the Greenwich Millennium Village (GMV) by Ralph Erskine, (a veteran of inner city housing in his seminal Byker Wall Project at Newcastle-upon-Tyne) together with EPR Architects Limited.[8] The concept is the total regeneration of the Greenwich Peninsula, particularly the site of the former gasworks, where the Millennium Dome[9] stands. Its proximity to central London and the City mean that its viability as a dormitory suburb on bus and train routes is practical. The discourse as to how to reuse ‘brownfield’ sites is to some extent resolved here, with the ultimate provision of some 900 residences by the end of 2007 with expansions continuing till 2015. The most important feature of this project is that a newly formed community is occupying the apartments that cater for a variety of different ‘social classes’, with a series of amenities such as an ‘eco-park’ green space, as well as office and retail developments. Using a prefabricated system, the buildings are hardy, but incorporate a generous use of colour. From the perspective of the environmental sustainability point of view, the rainwater is collected, grey water is recycled, insulation is good, which minimizes overheating by artificial means in winter, and the use of recycled materials such as timber, street furniture, and concrete has been a priority (GMV Fact Sheet 5[10]). Maximum efficiency is critical to the brief and in this regard, the website offers the following information- The need for artificial lighting is minimized by the provision of large windows meaning less running costs. These windows are made from environmentally sustainable material, and are also well insulated and draught proofed. Thermally, the buildings are constructed to standards 10% higher than the national standards, which assist in the reduction of emissions. Also, the highly coloured paint is specially chosen for its non-toxic values, and is a non-polluting paint. Water saving devices are used in all sanitary fittings, and plumbed appliances. The rooms in the apartments have sliding sections that maximizes flexibility and enables multiple uses of living space[11]. Power is supplied by a combined heat and power system (CHP) where the generated heat (as opposed to the generated power) is put to use. Excess power is sold off to the national grid (GMV Fact Sheet 4[12]) The energy constraints that were used as a benchmark in the design process ranged from the amount of energy required for manufacture, to the contribution their manufacturer makes to greenhouse gas emissions. The success of this project thus far has meant that the developers were the first large developers in the United Kingdom to be awarded the ‘Excellent Eco-Homes’ rating which is an incentive submitted by the Building Research Establishment to promote the construction of eco-friendly domestic buildings. This is certainly a far cry from the establishment’s attitude a few years ago! The multi-award winning BedZED (Beddington Zero Energy Development) completed in 2002 through the Peabody Trust with Bill Dunster Architects also puts these principles into practice. The mixed-use and mixed-tenure development of BedZED is the UK’s first and largest ‘carbon-neutral eco-community’, also built on a ‘brownfields’ site[13] in Sutton, near London. The concept behind the project was to produce as much energy from renewable sources as it consumes, creating a net zero-fossil energy development, and therefore a ‘carbon-neutral development’; it thus provides no net addition of CO2 to the atmosphere[14]. Smith describes the development as ‘a prescription for a social revolution; a prototype for how we should live in the twenty-first century if we are to enjoy a sustainable future. (Smith;2003:153) The BedZED design concept is itself a model of flexibility, with a variety of different forms of accommodation as well as different types of tenure. Altogether there are 82 homes of different sizes, some for sale and others rental units aimed at social housing income levels. Amenity is also important, cementing social sustainability, with facilities such as a kindergarten, health centre, commercial use node, exhibition centre and an organic shop! Environmental sustainability is ensured through the construction of massive walls that store heat for release in cooler periods. Also, a 300mm rock-wool insulation (Smith; 2003:54) provides for extra insulation on both the walls and the roof. The windows are triple glazed. Orientation plays a large part in the energy efficiency of the buildings, with north facing elevations of office and commercial space optimizing the softer light and minimizing the need for air-conditioning, whilst the homes, which benefit from the warmer orientation, face south. Low energy lighting is used where needed to assist in the reduction of electrical output. As with GMV, the choice of materials was dependant on their low embodied energy, and were sourced from suppliers as close as possible to minimize transport energy costs. The use of timber from sustainable sources, recycled materials, grey water recycling, solar power, and roof gardens serve to embed the environmental responsibility. Power is also supplied by a CHP plant. A critical point about BedZED is the minimizations of vehicle use- residents are encouraged through education and the ‘Green Transport Plan’ to promote alternative means of transport such as walking and cycling.[15] Also, the provision of efficient public transport means that the reliance on motor cars can be reduced. A larger infrastructural solution is that of the Vastra Hamnen waterfront development at Malmo in Southern Sweden. This used to be a ‘brownfields’ site that was part of the old dockyard. A number of architects including Erskine are involved with the project. The city was participant in the forming of the brief, dictating colour, ecological rigour, provision of park space, and minimal building performance. A wind turbine provides a large source of energy. Again, the complex is socially mixed, minimizing the potential for creating class-based residential neighbourhoods and there are shops on the street level, with the intention that the owners live above them. As in the previous example, the streets are car free and a pool of electric vehicles which are powered by wind energy is available to transport residents to town. Sewage enters the main system in the city, but other waste is dispensed of internally, where residents dispose of food in one tube and then dry waste in an other. The tubes lead to common disposal sites where the dry waste is incinerated and the food is composted providing biogas which returns to the occupants through the gas main. Smith considers this project as one that has ‘achieved reconciliation between market forces and environmental priorities.’ (Smith;2003:144) The single-building environmentally-efficient challenge was taken up by Sir Norman Foster and his partner Ken Shuttleworth in the Swiss Re Headquarters building, St Mary Axe. It remodeled a conceptual idea developed by Sir Buckminster Fuller and Foster in 1971 called the ‘Climatroffice’ which ‘suggested a new rapport between nature and workspace; its garden setting created a microclimate within and energy conscious enclosure, while its walls and roof were dissolved in a continuous triangulated skin. (Walker in Heartfield Abley;2001:207) Swiss Re was completed in 2004. It is notably the first building of its kind in England to manipulate environmental conditions to minimize air-conditioning, wind loads etc. The forty floors are designed as a series of rectangular plates that spiral up the building, assisting in daylight entering the building and reducing the amount of artificial lighting (Powell;2003:219) Revival of and recirculation of stale air is facilitated by roof gardens, also known as ‘bioclimatic terraces’ which re-oxygenate the building. These roof gardens are also used as social gathering spaces, which aids in increasing the quality of the work place. Most of the ventilation is natural, and unlike many buildings of its kind, the windows can all open. The base of the building has been formed to minimize wind load on the building and to minimize the creation of wind corridors so often found at street level in cities. (Powell;2001:219) The new age commitment to the environment and the lessening of emissions is often approached with zeal- Artist Freidensreich Hundertwasser was approached by the Mayor of Vienna to remodel the Spittelau Energy Plant. At first he turned it down, opposed to the assumed ecological failings embodied in the project. However, after assurances that the remodeling of the plant would be including the provisions for drastically reducing emissions, he took on the project for free. Working together with Architect Peter Pelikan, the industrial faà §ade was remodeled into a whimsical parody, where ‘The power plant†¦.. shows how to foreground the open creative spirit in harmony with nature and the anonymous city’ (Asensio;2003:31). Although this is not necessarily as direct an example as some of the new constructions mentioned above, I suggest that it is valid, given that the pressure to reuse buildings is a large part of architectural discourse, and is itself a tactic of sustaina bility and environmental recycling, the ‘greening’ of them in terms of minimizing emissions, changing technologies, and in this case mitigating the massive industrial-ness of the power station, makes it more socially environmentally friendly for the residents of Vienna. In the introduction to New Architecture in Britain, Powell states: ‘the future of architecture, in Britain and elsewhere is linked to such vital issues- the fate of our cities, the housing crisis and the protection of the earth’s fragile environment- that discussion of style seems almost irrelevant.’ (Powell;2003:20) This statement, in a glossy publication of contemporary architecture is a far cry from the plea made by Crowther less than a decade ago[16]. Whilst I agree with Powell that the language of architecture is changing, as it always does, the discussion of style is not irrelevant- low budget beauty and elegance is provided by the (highly theoretical) MGTH project, a mix of economic and social strata is contained in the Greenwich Millennium Village, a bold development more agreeable with the Vitruvian ‘Commodity and Firmness’, the BedZED and Vastra Hamnen developments that limit motor vehicles and provide the use of electric cars. Ironically, i t is perhaps the Swiss Re building, as Powell suggested in his 2001 volume ‘(that) reinforces the point that office towers can be distinctive, even beautiful, objects that complement, rather than deface, the skyline.’ (Powell;2001:219) which has managed to push the issue of sustainability and its connection with the very possibility of aesthetic beauty in the Vitruvian model into the forefront of populist architecture. However, we must not forget, in the clamour of the new, those early visionaries that promoted the values of engaging with the environment and treading with sensitivity. The investigations into the connection between culture, landscape, environment and architecture that informed the basis of the approach to the buildings built today, were seminal works of their time, situated in an alternative environment that was far too left of the modernist mainstream to find favour. But we can also feel thankful that finally, the discourse of environmentally friendly architecture has emerged in the mainstream- let us hope that it is not too late. References: Abley, I Heartfield, J (2001) Sustaining architecture in the anti-machine age Chichester, Wiley-Academy Andrews, J (1982) Architecture : a Performing art Lutterworth Press Asensio, P(2003) Freidensreich Hundertwasser Barcelona, LOFT Publications Cosanti Foundation(2000) Arcosanti Workshops 2000 (pamphlet) Phoenix, Cosanti Cosanti Foundation(2000) Cosanti-Arcosanti (pamphlet) Phoenix, Cosanti Crowther, R(1992) Ecologic architecture Massachusetts, Butterworth-Heinemann Curl, J (1999)Oxford Dictionary of Architecture Oxford, Oxford University Press Fitch, J(1960) Primitive Architecture and climate from Scientific American, December p134-144 Harrop-Allin, C(1975)Norman Eaton, Architect- a study of the work of the South African Architect Norman Eaton 1902-1966 Johannesburg, C Struik Publishers Marschall S (2000) Opportunities for Relevance Kearney, BPretoria, University of South African Press Pearson, D(1990) The Natural House book London, Conran Octopus Powell, K(2003) New architecture in Britain London, Merrel Powell, K(2001) New London architecture London, Merrel Rapaport, A(1969) House form and culture Prentice Hall Rudofsky, B (1965) Architecture without architects: a short introduction to non-pedigreed architecture New York, Museum of Modern Art Shelter Publications(1973) Shelter United States, Shelter Publications Smith, P (2003) Sustainability at the cutting edge : emerging technologies for low energy buildings Oxford, Architectural Press Vale, B(1991) Green architecture design for a sustainable future London, Thames and Hudson Websites: http://www.greenwich-village.co.uk/index_main.htm (17.06.07) http://www.arcosanti.org/ (17.06.07) http://www.peabody.org.uk/pages/GetPage.aspx?id=179 http://www.inhabitat.com/2007/0 6/15/prefab-friday-modular-transitional-growth/#more-4683 (17.06.07) 1 Footnotes [1] Sustainability as an idea was a large component of ‘development speak’ in the context of poverty and limited resources. This embraced notions of community participation as well as optimizing resources. [2] The Oxford Dictionary of Architecture notes that ‘ecological architecture- Aims to respond to declining energy resources, eg using energy conservation, efficient insulation, rainwater, solar radiation, and wind power, and recycling as much as possible. The term was coined in the 1970’s’ (Curl;1999;220). Similarly, ‘green architecture- Buildings designed according to energy-saving criteria and the reduction of pollution.’ (Ibid;288). [3] From the third chapter of Vitruvius De Architectura comes the definition of beauty in architecture as firmitas, utilitas, venustas or Commodity, Firmness and Delight. The practicality of the building, as well as its robustness is as important as its beauty. [4] The necessity to incorporate en

Techniques for Authentic Assessment :: Learning Education Educational Essays

Techniques for Authentic Assessment Learning is . . . a dynamic process in which learners actively construct knowledge . . . the acquisition and organization of information into a series of increasingly complex understandings . . . influenced by context (Holt 1992). Educators who view learning in this way realize that quantitative methods of evaluating learners do not "measure up." Authentic forms of assessment present a more qualitative and valid alternative. Authentic assessments (AAs) incorporate a wide variety of techniques "designed to correspond as closely as possible to `real world' student experiences" (Custer 1994, p. 66). They are compatible with adult, career, and vocational education. After all, apprenticeship is a time-honored form of authentic learning: skills taught in context. "High-performance workplaces" demand critical thinking, self-directed learning, and individual responsibility for career development (Borthwick 1995; Jones 1994)-which the process of AA can develop. This Practice Application Brief describes types of authentic assessment, explains some of the advantages and challenges they present, and highlights some best practices in design and implementation, with specific examples from adult, career, and vocational education. What Are AAs? Assessments are authentic when they have meaning in themselves-when the learning they measure has value beyond the classroom and is meaningful to the learner. AAs address the skills and abilities needed to perform actual tasks. The following are some tools used in authentic assessment (Custer 1994; Lazar and Bean 1991; Reif 1995; Rudner and Boston 1994): checklists (of learner goals, writing/reading progress, writing/reading fluency, learning contracts, etc.); simulations; essays and other writing samples; demonstrations or performances; intake and progress interviews; oral presentations; informal and formal observations by instructors, peers, and others; self-assessments; and constructed-response questions. Students might be asked to evaluate case studies, write definitions and defend them orally, perform role plays, or have oral readings recorded on tape. They might collect writing folders that include drafts and revisions showing changes in spelling and mechanics, revision strateg ies, and their history as a writer. Perhaps the most widely used technique is portfolio assessment. Portfolios are a collection of learner work over time. They may include research papers, book reports, journals, logs, photographs, drawings, video and audiotapes, abstracts of readings, group projects, software, slides, test results; in fact, many of the assessment tools listed earlier could have a place in a portfolio. However, the hallmark of a portfolio used for assessment is that the contents are selected by the learner (Hayes et al.

Star government

But with the government moving to reduce the countrys reliance on subsidies for uel, energy efficiency and sustainability are becoming important elements for businesses to look into as a means of controlling costs. The pump price of fuel was recently raised by 20 sen. As a result of this a hike in the cost of almost everything else Is expected to follow. The need for energy efficiency Is particularly telling for the small and medium enterprises (SME) given that they don't always have the economies of scale that larger corporauons do.The rising cost of energy will be a new challenge for SMEs In their quest to stay ahead of the curve in Increasingly competitive markets. Kenmart: Being energy efficient is not Just about cutting your cost of energy. It is also about being more productive in using your energy. â€Å"Looking at the current situation, SMEs will need to look at alternatives to differentiate themselves In the market. Energy efficiency is not Just hype. It will help them to b e more cost-competitive,† said Kristo Kenmart, head of industry business for Schneider Electric Industries (M) Sdn Bhd.The Schneider Electric Group Is a French multinational corporation that specialises in energy management. It currently has operations in more than 100 tOf3 wages are rising and the price of petrol has gone up. This means a significant increase in cost for SMEs,† Kenmart said. SMEs can reduce one of their main cost components by being energy efficient, he said. Energy has become one of the strategic factors driving business decisions and competitiveness. Businesses and consumers are increasingly considering the energy efficiency of the products and services they buy and use to yield maximum return on investment (ROI).Governments are also starting to see the importance of supporting the energy- efficiency agenda among SMEs. Schneider Electric offers solutions for companies in a wide range of industries. The Singapore government estimates that energy costs make up about 13% of the operating costs for the countrys manufacturing SMEs and it recently announced a S $17mil (RM42. 8mil) allocation to help SMEs assess, monitor and improve their energy efficiency. The goal of the initiative is to help some 300 SMEs achieve at least 10% savings in energy costs over the next three years.Australia has similarly rolled out an energy sustainability programme for SMEs. Malaysia has yet to announce its Energy Efficiency Master Plan and there is currently little effort in addressing energy efficiency in the SME sector. However, the Government has pledged to reduce Malaysia's carbon footprint by 40% by 2020. Kenmart believes that the current economic condition in Malaysia will accelerate the awareness energy efficiency and efforts to educate companies about the need for it. We have seen some clients looking seriously into it. The number of companies doing this is growing daily. But being energy efficient is not Just about cutting your cost of energy. It is also about being more productive in using your energy or getting more out of the energy that you are using,† he said. Schneider Electric offers various energy-efficiency solutions or clients across all industries to boost the productivity of energy through technology and processes.The adoption of energy-efficient solutions among SMEs here is in its infancy, which spells plenty of growth opportunities for Schneider Electric to further explore this segment of business. â€Å"There is still a lot of opportunity to develop the business here. Certainly there are many challenges. But we have also seen many successes as well,† he said. He acknowledges that among the main concerns for many companies in implementing energy-efficiency solutions is the cost of implementation nd the ROI period, which is understandable given their limited resources.Notably, there is no one-size-fits-all kind of solution as SMEs vary in size and operations. Schneider Electric has carved out spe cific solutions for the various types of SME outfits according to the industries they are in, such as data centres, manufacturing and service providers. But Kenmart assured that Schneider Electric has documented the typical benefits and ROI for companies embarking on such solutions. He says the company's solutions also often include proposals on how to fund the adoption of nergy efficiency.

History of computer mouse - Free Essay Example

Sample details Pages: 26 Words: 7759 Downloads: 8 Date added: 2017/06/26 Category Statistics Essay Did you like this example? History of computer mouse Dr. Douglas Engelbart has invented the first device that came out as mouse in the year1964.During this time the only way of moving the cursor around on a computer screen was using the arrow keys on the keyboard and it was really inefficient and awkward to use. A small brick like mechanism with one button on top and two wheels on the underside was made by Douglas. Don’t waste time! Our writers will create an original "History of computer mouse" essay for you Create order The purpose of these wheels is to detect horizontal and vertical movement and on the whole the unit was little bit difficult to use. For viewing the cursor on the monitor this unit was linked to the computer by a cable so the motion signals could be electrically transmitted .As the device with its long cable tail looked like a mouse so the name mouse came into picture.NASA team tried different methods of moving cursors and pointing to objects on the computer screen like the devices steering wheels, knee switches, and light pens, but in tests of these devices Engel arts mouse gained popularity. Engineers thought that the mouse was perfect for drawing and drafting purposes and could develop computer aided designs at their own desks. Slowly mouse began to be called as input/output device. To make the scrolling easier the mouse began to multiply rapidly and to make the mouse cordless by using the radio frequency signals. Mouse tail is the electrical cable leading out of one end and the o ther end is used for connecting to the central processing unit. Composition of the Mouse Body of the mouse: * The outer surface of the mouse is Hard plastic body which the user guides across a flat surface * The tail of a mouse is an electrical cable that leads out from one end and finishes at the connection at the Central Processing Unit * It has one to three buttons at the tail end which are external contacts to tiny electrical switches * With a click on the button the electrical circuit is forced to close and the computer receives a command * Below the mouse theres an plastic hatch that fits over a rubberized ball which exposes a small part of the ball * A support wheel and two shafts hold the ball in place inside the Mouse * Rotation of the spokes causes IR light signals from light emitting diode to flick through the spoke which are then captured by a light detector * Phototransistors help to translate these light signals into electrical pulses which reach the integrated circuit interface in the mouse * These pulses then confirms the IC whether the ball has followed an up down or left right movement * The IC commands the cursor to move on the screen accordingly * The interface IC is then ascended onto a printed circuit board * This forms the skeleton to which each and every internal workings of the mouse are attached * The information from the switches and signals from the phototransistors is collected by a computer chip or IC * These are then sent to the computer by means of a data stream The Brain of the Mouse: * Every mouse design consists of an individual software known as driver * These driver are external brain that enables the computer to understand the mouse signals * The driver tells the computer how to interpret the mouses IC data stream including speed, direction, and clicked commands * Some mouse drivers allow the user to assign specific actions to the buttons and to adjust the mouses resolution (the relative distances the mouse and the cursor travel). * The Mouse which are purchased as a part of computer packages have built in drivers or is programmed initially in the computers (Source: Fig 1 Internal circuit of the mouse https://www.ehow.com/how-does_4574328_computer-mouse-work.html RAW MATERIALS IN THE MOUSE The outer shell of the mouse and the majority of its internal parts, which includes spoked wheels and shafts are usually made up of Acrylonitrile Butadiene Styrene (ABS) plastic which is usually injection moulded. The ball is basically made of metal which is rubber coated and is usually supplied by a speciality supplier The electrical micro switches which is produced from metal and plastic are of shelf items which are supplied by subcontractors even though the designers of the mouse can specify force requirements for switches to make it easier of harder to click. The chips or IC could be standard items even though individual manufacturer might have proprietary chips which can be utilised in its complete products line. The outside source also supplies electrical cables and over moulds To suit the design of mouse the printed circuit board (PCB) over which the mechanical and electrical components are mounted are custom made Oscillators, integrated circuits, capacitors, electrical resistors and various other components are made of different types of plastic, metal and silicon The raw materials which are used in manufacturing of a computer mouse are as follows: Component name Material mouse ball Low alloy steel Housing Acrylonitrile butadiene styrene (ABS) insulation wire Polyvinylchloride (tpPVC) rubber material Polyurethane (tpPUR) USB inside part Stainless steel plastic part inside USB Phenolics USB jack(casing) Acrylonitrile butadiene styrene (ABS) internal wires Copper Mouse Design The new mouse starts with associations with product development manager, marketing representative, designer and a consulting ergonomist. A list of human factors guidelines are formed which indicate the size range of hands, amount of work, touch sensitivity, support of hand in a neutral position, while operating the mouse the users posture, finger extension needed to reach the buttons, use by both right and left handed individuals, no prolonged static electricity and lastly the requirements safety and comfort They alter widely depending on whether the use of mouse is in home or office computers The brief design of mouse for the proposed mouse is written to explain the purpose of the product and what it attains; an appearance is also proposed in staying along with the probable market. The design team comes back to the table along with foam models; for a single mouse design scores of various shapes are made on these models the user testing is done whereas the preliminary tests are perf ormed by engineers or the focus may be turned onto groups as typical users or observes one to one testing with user samples. (Source: Fig 2 Design of the mouse https://www.computerhope.com/jargon/m/mouse.htm ) When a suitable selection is chosen, wooden models which are more refined and painted are produced from the winning design. Based on the feel, shape and looks of the model input is gathered again and the ergonomist reviews the probable designs and confirms the goal of human factors guidelines to be achieved. After an optimal design is chosen the engineering team starts designing the internal components. A three dimensional rendering is generated by the computer and the same data are used to machine cut the shape of the interiors of the exterior shell with every details. Inside the structure the mechanical and electronic engineers fit the printed circuit board and the encoder mechanism. The phenomena of fitting the workings on to the shell is iterative, the changes are then made and then the design and fit process are repeated until the mouse achieves the design objectives and the design team is happy. The custom chips are then designed and produced on a trial basis and then tested; for the design to meet the performance objectives and provide it unique, competitive and marketable characteristics the help of custom electronics is required. The fully completed design figures are handed over to the project tooled who then starts the process of modifying machines to manufacture the mouse. To generate the injection moulding of the shell tooling diagrams are made into use. The size, shape, volume of the cavity, the number of gates through which the plastic will be injected into the mould, and the flow of the plastic through the mold are all diagrammed and studied. After reviewing the final tooling plans the tools are cut using computer generated data. Sample plastic shells are made as try shots to find out the actual flow lines and to make sure that voids are not included. Changes are made till the process is perfect. Texture is added to the external appearance of the shell by sand blasting or by acid etching. The Manufacturing Process: To manufacture a computer mouse several processes are used to make different pieces of the unit. The processes that are used in manufacturing are as follows 1. First the Printed Circuit board (PCB) is prepared in the journey of manufacturing and assembling steps. This board is a flat, resin coated sheet that can be of surface-mount design or through hole design. The assembly of surface mount version is entirely done by the machine. The other electrical components are placed on to the board in prescribed pattern by a computer controlled automatic sequencer. In the PCB assembly, the attachment wires of the electronic components are inserted in holes. Then all the components are mounted on the board, the bottom surface is passed through molten lead solder in a soldering machine. This machine removes contaminants by passing the board with flux. The board is gently heated by the machine and the components it carries by infrared heat is to lessen the possibility of thermal shock. The solder raises each line by hair-like activity, seals the perforations and repairs the components in the correct place. . After this process is done the PCB is cooled and is visually inspected before the mechanism is attached. 2.A separate unit is assembled for the encoder mechanism. Injection moulding process is make used to manufacture the plastic parts (computer mouse case housing) with proper specifications and the left over scrap plastic material is trimmed off. The whole unit is fastened to the PC Board using screws keeping in view after the encoder mechanism is completely assembled. Using a set of wires ,shielding and rubber cover the mouses tail and its electrical cable attached are manufactured. Overmolds are the additional pieces of the cable to prevent the cable from detaching from the mouse. We can make our own shapes of design for overmolds, the near mouse overmold is hooked to the housing at the opposite end of the tail, the connector is soldered to the wires and the connector overmold is pop pled into place. 2. The pieces of the outer shell are visually inspected after moulding, trimming, and surface (finish) treatment and prior to assembly. The external housing is assembled in four steps. To the bottom of the shell the completed PCB and encoder assembly are inserted. The buttons are fitted into the top part of the housing, attaching the cable and the top and bottom are screwed together using automated screwdrivers. 3. The final electronics and the achievement quality inspection are accomplished, if assembly is complete in the substantial one. Rubber or neoprene feet with the adhesive covering in front-turned at a side is added the lower surface of the mouse. 4. A programming team has been developing,testing,reproducing the mouse driver firm ware, while the the tooling designs and physical assembly are in progress. As above said firmware is the combination of software and hardware codes which has the unity of integrated circuit,translated mouse directional movements and micro switch signals which are understood when the mouse is attached. By-products and waste: Computer mice makers do not generate by-products from mouse manufacture, but most offer a range of similar devices for different applications. In order to avoid the design, tooling, assembly modification costs the new and multiple designs are in corporate when possible. Waste is minimal. The mouses ABS plastic skin is highly recyclable and can be ground, moulded, and reground many times. Small quantities can be recycled using metal scrap and other plastics. ECO AUDIT TOOL INTRODUCTION: Eco audit tool enables the product designers to quickly evaluate the environmental impact of a product, and it helps to reduce the environmental measures. By making use of CES software, this can be achieved by focussing on two environmental stressors * ENERGY USAGE * CARBON FOOTPRINT considering the main product life phases of a product Overview of component lifecycle (Source: https://www.treehugger.com/RONA-product-life-cycle-graphic.JPG ) Example output from the eco audit tool (Source: https://www.grantadesign.com/images/selector09/EcoAuditGraph.jpg ) To minimize the environmental footprint of a product, identification of the dominant phase is very important and it enables a designer to establish which aspect of the design to target The result of the eco audit forms the objective for the product design. This objective is dependent on both the dominant phase and the product application. Figure Examples of design objectives associated with minimizing the environmental impact of the main life (Source: https://www.grantadesign.com/images/audit-strategies.jpg ) Life Cycle Analysis: The Life cycle analysis of the product life cycle is split into three main sections in the eco audit tool: 1. Material, manufacture, and end of life 2. Transport 3. Use 1. Material, manufacture, and end of life This the first section of the product definition which allows us to enter the Bill of Materials'(BOM) for the product, with each line representing an individual component. There is no limit on the number of components that can be added. Reading across the input dialog box, the entries are as follows Quantity This column tells us about the different number of individual components that are used in making of the product. This quantity column enables the specification of duplicate components in a hierarchal order. . The default value is one because there is no product with zero quantity. Component name It is the dialogue box for entering the name of each individual component of the product. Material The material drop-down menu displays the full Material Universe tree of the active database. Materials are selected by browsing the tree and clicking on the record for the material of our interest. Once we have done this, the eco audit tool extracts data from the material record to determine what options to display in the Primary process and End of life menus. Certain products include components that do not contribute to all life phases. For example, the water in a drinks bottle contributes to the transportation phase but not the material and manufacturing phases. This contribution is handled by creating a dummy component with no material, or process, assigned to it. Recycle content We have three recycle contents which can be specified as 0%, 100%, and typical %. As the names suggest, 0% represents the use of virgin material, where all the feedstock is produced from raw materials. 100% represents the other intense, where the material is manufactured entirely from feedstock reclaimed from end of life components. Typical %, lies between these two extremes and accounts for the level of recycled material incorporated back into the supply chain as standard practice. This applies to materials, such as metals and glasses, where end of life recycling has become integrated into the supply chain. This practice leads to standard grades containing significant levels of recycled material. For example, lead alloys generally contain 50-60% recycled material. Although many materials can be recycled, and have recycle fraction in current supply values quoted in the Material universe database, they are not routinely reintroduced into the standard supply. As a result, the typical recycle content option is only displayed for grades of metal and glass that are flagged as recyclable. Primary process The primary process dropdown menu displays the processes that are applicable to the material selected from the tree. This information, and associated data, is extracted from the materials datasheet. The available primary processes in the database are shown in the below table. Table 1. Available primary processes (Level 1 and 2 database) Material Process Metals Casting Forging Metal powder forming Vaporization Polymers elastomers Polymer molding Polymer extrusion Technical ceramics Ceramic powder forming Non-technical ceramics Assembly and construction Glasses Glass molding Composites Casting Simple composites forming Advanced composite forming Natural materials Assembly and construction Electrical components As electrical components are finished sub-assemblies, the material and process energies (and CO2) have been incorporated into one value [Embodied energy, primary production]. As a consequence, no processing options are available for these components. Mass (kg) Numeric field for specifying the mass of the component. This value is multiplied by the quantity (Qty) field value to determine the total mass for the component. End of Life This drop-down menu displays all possible end of life options for the selected material. There are seven end of life options and their applicable materials. Out of these seven, the first four are directly displayed on the datasheet depending on the type of material. The remaining life options are not specified and are added as other possible options for all materials. The end of life option generally defaults to Landfill. The main exception is for toxic materials, which default to the next viable option (usually in down cycle order). Table : describes the possible end life options and their Summary related to the materials End of life option Applicable materials Landfill All non-toxic materials Combust (for energy recovery) All organic-based materials with a heat of combustion value 5 MJ/kg Downcycle All Recycle All unfilled: metals / glasses / thermoplastics /TPEs Particulate filled thermoplastics Particulate whisker reinforced metals (All ceramics / thermosets / elastomers / natural organic / natural inorganic materials and all fiber reinforced materials are marked as non-recyclable) Re-engineer All Reuse All blank All 2. Transport Transportation phase is the second part of the product definition. This phase relates to the transport of the finished product from the source of manufacture to the customer Each line in the table relates to one stage of the process journey. There is no limit on the number of stages that can be added. For each stage, three parameters are defined: stage name, transport efficiency (transport type), and distance. The transport efficiency is specified through the transport type dropdown menu, which lists the main methods for transporting goods. Table : transport options and associated environmental burden Transport energy (MJ/tonne/km) Carbon footprint, source (kg/MJ) Sea freight 0.16 0.071 River / canal freight 0.27 0.071 Rail freight 0.31 0.071 32 tonne truck 0.46 0.071 14 tonne truck 0.85 0.071 Light goods vehicle 1.4 0.071 Air freight long haul 8.3 0.067 Air freight short haul 15 0.067 Helicopter Euro copter AS 350 50 0.067 To determine the environmental impact of each stage the energy usage and the carbon foot print values are combined with the product mass and distance. i.e. Energy usage is given by Transport Energy =Transport energy per unit mass * distance * product mass. And carbon foot print by Transport co2=Transport energy per unit mass*Distance*product mass*carbon foot print. 3. Use The final stage of the product definition is the use phase. Product life Numeric field for specifying the product life, in years. The value for the year is considered to be default (1). Country electricity mix The Country electricity mix drop-down menu enables the particular mix of fossil and non-fossil fuel of the country of use to be specified. This is split into three main groups: global regions, individual countries, and fossil fuel percentage. The default option is World. Compared to the other sources, such as nuclear, hydroelectric and wind power, the environmental burden of electricity generated from fossil fuels is significantly higher. So this specification of country of use is very important phase of the eco audit tool. This is due to the relatively low efficiency in converting fossil fuels to electricity (1MJ of electricity requires about 3MJ of fossil fuel). The impact of a countrys energy mix on the energy equivalence and carbon footprint of its electricity supply is summarized in Figure3. Figure 3. Country electricity mix: Energy equivalence carbon footprint per MJ of electricity used (Source: https://images.google.co.uk/imgres?imgurl=https://www.additiverich.com ) The final grouping in the country electricity mix menu specifies the electricity mix based on the proportion derived from fossil fuels (0% to 100% at 5% intervals). The environmental impact of these has been calculated using the following assumptions: a) The carbon footprint of electricity is dominated by the contribution from fossil fuels, with the proportion derived from other sources having no, or negligible, contribution. b) And the conversion process for generating electricity from fossil fuels is taken to be 33% efficient. In this use phase we have two modes namely static mode and mobile mode which describes the product energy usage. In static mode the available options are energy input and output which describes the conversion of one form of energy into another, power rating and usage. In the mobile mode, we have fuel and mobility type and its usage. Modes of use The use phase is divided into two modes of operation, static, and mobile. Static relates to products that are (normally) stationary but require energy to function. For example: electrically powered products like electric kettles, refrigerators, and power tools. Mobile relates to transportation systems, where mass has a large influence on energy consumption. To define these modes of use, check the static mode and mobile mode boxes. For products that operate in both modes, check both boxes. Static mode: Three parameters define the static use mode: Product efficiency, power rating, and the duty cycle. The product efficiency is specified through the Energy input and output dropdown menu. This specifies the energy conversion efficiency of the product and the environmental burden associated with its energy source . For electric products, the energy equivalence and carbon footprint values depend on the country of use Table : Available energy conversion options and associated environmental data Input and output type Product efficiency Energy equivalence, source (MJ/MJ) Carbon footprint, source (kg/MJ) Electric to thermal 1 Country specific Country specific Electric to mechanical (electric motors) 0.89 Country specific Country specific Electric to chemical (lead acid battery) 0.83 Country specific Country specific Electric to chemical (advanced battery) 0.89 Country specific Country specific Electric to em radiation (incandescent lamp) 0.17 Country specific Country specific Electric to em radiation (LED) 0.86 Country specific Country specific Fossil fuel to thermal, enclosed system 1 1 0.071 Fossil fuel to thermal, vented system 0.70 1 0.071 Fossil fuel to electric 0.35 1 0.071 Fossil fuel to mechanical, internal combustion 0.30 1 0.071 Fossil fuel to mechanical, steam turbine 0.40 1 0.071 Fossil fuel to mechanical, gas turbine 0.48 1 0.071 Light to electric (solar cell) 1* 1 0 The product power rating and duty cycle are specified by the Power rating and Usage inputs. These parameters are combined with the product efficiency values to determine the static mode contribution: Static energy (J) =power rating (W)*duty cycle*(energy equivalence /production efficiency) Static use CO2(kg) = ((power rating (W)*duty cycle)/1*10^6)) *(carbon footprint/production efficiency) Where : Duty cycle(S)=production life (years)*days per year*(house per day*3600) Mobile mode: The mobile use mode is defined by three parameters: The transport type, efficiency, and the distance travelled over the products life. The transportation type and efficiency is specified through the Fuel and mobility type drop-down menu. This determines the environmental burden associated with the transportation and fuel type . For electric transportation modes, the energy equivalence and carbon footprint values depend on the country of use. Table 5. Available fuel and mobility types and associated environmental data Fuel and vehicle type Energy (MJ/tonne.km) Energy equivalence, source (MJ/MJ) Carbon footprint, source (kg/MJ) Diesel ocean shipping 0.16 1 0.071 Diesel coastal shipping 0.27 1 0.071 Diesel rail 0.31 1 0.071 Diesel heavy goods vehicle 0.90 1 0.071 Diesel light goods vehicle 1.4 1 0.071 Diesel family car 1.6 1 0.071 Electric family car 0.17 Country specific Country specific Electric rail 0.11 Country specific Country specific Gasoline hybrid family car 1.1 1 0.071 Gasoline family car 2.1 1 0.071 Gasoline super sports and SUV 4.8 1 0.071 Kerosene long haul aircraft 8.3 1 0.067 Kerosene short haul aircraft 15 1 0.067 Kerosene helicopter (Eurocopter AS 350) 50 1 0.067 LPG family car 3.9 1 0.58 These values are combined with the product usage and distance parameters to determine the contribution of the mobile mode: Source 🙠 Granta Design,Cambridge,UK ,2009) Report: The final section in the product definition allows an image and notes to be added to the eco audit report. This is compiled by clicking on the View Report button. These can be categorised into three sections: 1. Summary page provides an overview of the eco audit, with headline values for each life phase. This enables rapid identification of the dominant life phase. 2. Detailed breakdown of energy usage (accessed via Energy Details link on summary page) provides a component-by-component breakdown of each life phase, enabling the main contributors to the dominant phase to be identified. This page lists all data and calculation factors used by the eco audit tool. 3. Detailed breakdown of carbon footprint (accessed via CO2 Details link on summary page) similar to above, except for carbon footprint. The summary table quotes two totals for energy and CO2. The first value, Total, sums the environmental burden associated with the life of the existing product this is similar to the approach used by life cycle assessment (LCA) techniques. The second value, Total (including end of life saving/burden), includes end of life benefits that are realized in future life cycles. This value is useful for designers, looking to design for the environment, as it enables them to maximize the benefits that could be realized in future life cycles. Source 🙠 Granta Design,Cambridge,UK ,2009) Product name: Computer Ball Mouse, BOM: Life: 4 years COMPUTER BALL MOUSE: Figure below shows a typical computer ball mouse. The bill of materials (BOM) of the product is listed in table. The computer mouse is manufactured in south East Asia and transported to Europe by air freight, a distance of 11,000 km then distributed by 24 tonne truck over a further 275 km. The power rating is 15 W and the mass is 68.5 gms .The computer ball mouse is a pointing device used to generate movement commands for controlling a cursor position displayed on a computer monitor or a laptop. Step 1: Materials and manufacture: 100 units Material: Breakdown by component Component Material Recycle content Material Embodied Energy * (MJ/kg) Total Mass (kg) Energy (MJ) % mouse ball Low alloy steel Typical % 24.338 0.015 0.365 3.38 Housing Acrylonitrile butadiene styrene (ABS) 100% 40.423 0.062 2.506 23.23 insulation wire Polyvinylchloride (tpPVC) 100% 33.757 0.030 1.013 9.39 rubber material Polyurethane (tpPUR) 100% 49.916 0.012 0.599 5.55 USB inside part Stainless steel Typical % 59.288 0.005 0.296 2.75 plasticpart inside USB Phenolics 0% (virgin) 90.335 0.006 0.542 5.02 USB jack(casing) Acrylonitrile butadiene styrene (ABS) 100% 40.423 0.021 0.849 7.87 internal wires Copper Typical % 48.115 0.096 4.619 42.81 Total 0.247 10.789 100 Mass and energy data for material phase Component Qty. Part mass (kg) Embodied Energy, primary production (MJ/kg) Recycle fraction in current supply (%) Embodied Energy, recycling (MJ/kg) mouse ball 1 0.015 34.871 41.952 9.764 Housing 2 0.031 96.343 0.707 40.423 insulation wire 3 0.010 80.374 0.707 33.757 rubber material 4 0.003 118.849 0.707 49.916 USB inside part 5 0.001 81.149 37.417 22.722 plasticpart inside USB 6 0.001 90.335 0.707 0.000 USB jack(casing) 7 0.003 96.343 0.707 40.423 internal wires 8 0.012 70.937 42.895 17.734 The bar chart in the below figure shows the energy breakdown delivered by the eco audit tool. Table show the energy and co2 summary Manufacture: Breakdown by component Component Process Processing Energy (MJ/kg) Total Mass (kg) Energy (MJ) % mouse ball Casting 4.173 0.015 0.063 4.21 housing Polymer molding 10.958 0.062 0.679 45.67 insulation wire Polymer extrusion 3.575 0.030 0.107 7.21 rubber material Polymer molding 10.129 0.012 0.122 8.17 USB inside part Casting 4.140 0.005 0.021 1.39 plasticpart inside USB Polymer molding 12.755 0.006 0.077 5.14 USB jack(casing) Polymer molding 10.958 0.021 0.230 15.47 internal wires Forging, rolling 1.975 0.096 0.190 12.74 Total 0.247 1.488 100 Step 2: Transport For step 2 it retrieved the energy and CO2 profile of the selected transport mode from a look-up table. Transport: Breakdown by transport stage Total product mass = 0.25 kg Stage Name Transport Type Transport Energy (MJ/tonne.km) Distance (km) Energy (MJ) % East Europe Rail freight 0.310 2500.000 0.191 26.00 Rotherham 14 tonne truck 0.850 126.000 0.026 3.59 Hampshire Light goods vehicle 1.400 308.000 0.107 14.47 Birmingham 14 tonne truck 0.850 75.000 0.016 2.14 East Europe Rail freight 0.310 2500.000 0.191 26.00 Stortford 14 tonne truck 0.850 351.000 0.074 10.01 Rothernham 14 tonne truck 0.850 126.200 0.026 3.60 Sussex Light goods vehicle 1.400 302.000 0.104 14.19 Total 6288.200 0.736 100 Breakdown by components Total transport distance = 6.3e+03 km Component Total Mass (kg) Energy (MJ) % mouse ball 0.015 0.045 6.07 Housing 0.062 0.185 25.10 insulation wire 0.030 0.089 12.15 rubber material 0.012 0.036 4.86 USB inside part 0.005 0.015 2.02 plasticpart inside USB 0.006 0.018 2.43 USB jack(casing) 0.021 0.063 8.50 internal wires 0.096 0.286 38.87 Total 0.247 0.736 100 It then multiplies these by the total weight of the product and the distance travelled. If more than one Transport stage is entered; the tool sums them, storing the sum. For step 3 the tool retrieves an efficiency factor for the chosen energy conversion mode (here electric to mechanical) finding in its look-up table. STEP 3: USE PHASE: STATIC MODE Use: Mode Energy (MJ) % Static 0.000 Mobile 0.000 Total 0.000 100 The tool uses this and the user-entered values for power and usage to calculate the energy and CO2 profile of the use phase. For the final step 4 the tool retrieved the recycle energy and recycle fraction in current supply for each material and replaced the energy and CO2 profiles for virgin materials with values for materials made with this fraction of recycled content. Finally it created a bar chart and summary of energy or CO2 according to user-choice and a report detailing the results of each step of the calculation. An overall reassessment of the eco impact of the computer mouse should, of course, explore ways of reducing energy and carbon in all four phases of life, seeking the most efficient methods. Housing Materials selected are : 1) Acrylonitrile butadiene styrene (ABS) Plastic 2) Polymethyl methacrylate (acrylic,PMMA) 3) Polystyrene (PS) Materials used in computer mouse Copper Copper is used in the wiring for tail of the mouse . Copper is an excellent electrical conductor which is extremely used in wiring for power lighting ,heating and several daily purposes ,but copper are not used directly ,they are bounded with insulation wire .The metal is also used in electric and electronic compounds ,so that it can flow electricity very easily ,as it is a good conductor of electricity ,this is type of metal in which there are many types of contents present in the same form and in general cadmium free copper is known with the name electrolyte copper which is 100 pure. Year by year the usage of copper is increasing, at present every year 15 million tonnes of copper is used .copper has several properties which are combidely remarkable .It is a good electrical and thermal conductor it is ductile and can prevent bacterial growth .recycling of copper is important as it is limited .And recycling of copper is well suited as it can be re melted without losing the properties. Extraction of copper In nature the metal are found in compounds which are usually combined with oxygen. The compounds are mixed up in rocks or minerals which are called as ores. A ore is a rock that has enough metal in it to make it worth extracting the metal. The main ore of copper are * Chalcopyrite * Bornite * Malachite The tree main stages of extracting copper are * Mining * Extraction * Purification Mining process: In this process the copper ore will be dug form the ground. The ore contains some mineral and lot of waste rock. For every 1000 tones 6 tonnes of copper can be extracted. Copper electrolyte Copper sulphate fig explains us the electrolysis process extracting copper. Extraction process: In this process the ore has to be changed in to metal ,this process is called reduction. The table explains us the extraction of copper and process used. Metal Ore Reactivity Primary process Copper Various ore Low Roasting in air Purification: In this process many metal are impure when they are extracted from there ores, impurities have to be removed copper is purified by electrolysis process as mentioned above in the figure; the copper is transformed from an impure anode to cathode of an electrolytic cell. The copper produced by this process is 99.99% pure. Recycling of copper is very important: This process of recycling has several advantages like price, limited resources, energy efficiency, land fills costs, and the last important thing is environment. Manufacturing process of copper used in mouse cable: There are two process used in manufacturing they are rolling and forging. USB INSIDE PART (METAL) 1) Stainless steel 2) Medium carbon steel 3) High carbon steel 4) Low carbon steel Stain less steel: U.S.B port is made of stain less steel .stainless steel is defined as in ox steel which is defined as alloy steel with 11% chromium content by mass, it is stainless steel because of the content In addition to iron, carbon, and chromium, modern stainless steel may also contain other elements, such as nickel, niobium, molybdenum, and titanium. It is the addition of a minimum of 12% chromium to the steel that makes it resist rust, or stain less than other types of steel. The invisible layer chrome-containing oxide named passive film can be formed by the mixture of oxygen in the atmosphere and chromium in the steel. The sizes of chromium atoms and their oxides are similar, so they pack together on the surface of the metal, forming a stable layer only a few atoms thick. If the metal is cut or scratched and the passive film is disrupted, more oxide will quickly form and recover the exposed surface, protecting it from oxidative corrosion. Iron, on the other hand, rust quickly because atomic iron is much smaller than its oxide, so the oxide forms a loose rather than tightly-packed layer and flakes away. The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistance in low-oxygen and poor circulation environments. In seawater, chlorides from the salt will attack and destroy the passive film more quickly than it can be repaired in a low oxygen environment of chromium. Manufacturing process: The manufacture of stain less involve several process in the first the steel is melted and then it is casted in to solid form, the heat treatment is done in then it is cleaned and the polishing of the metal is done when the desired shape is achieved. The stages of extracting stain less steel are * Melting and casting * Forming * Heat treatment * De scaling * Cutting * finishing Melting and casting: In this process the raw materials are melted together in an electric furnace. The whole process takes half days for intense heat. After the melting is done, the molten steel will be casted into different forms which include blooms (rectangular shapes), billets which are round or square in shape with 1.5 inches or 3.8 centimetres in thickness, slabs, rods, and tube rounds. Forming: The semi finished steel goes through the forming operations with hot rolling in which heat is formed to steel and the steel is heated and passed through huge rolls .where the stain less steel is formed. Heat treatment: Most types must go through an annealing step, before stainless steel is formed. Annealing is a heat treatment where steel is heated and cooled under controlled conditions to relieve internal stresses and soften the metal. De scaling :De scaling is a process where Annealing is caused to build-up to form on the steel. The scale can be removed using several processes. The de scaling steps occur at different stages depending on the type of steel being worked. Bar and wire, for instance, go through further forming steps like hot rolling, forging, or extruding, after the initial hot rolling before being annealed and descaled. Sheet and strip, go through an initial annealing and descaling step after hot rolling. After cold rolling passing through rolls at a relatively low temperature, which produces a further reduction in thickness, sheet and strip are annealed and descaled again,a final cold rolling step then prepares the steel leading to final processing. Cutting : In this process the stainless steel is done with Cutting operations which are usually necessary to obtain the desired blank shape or size to trim the part to final size. Mechanical cutting is commonly obtained to the cut in to the desired shapes Finishing: Finishing is an important process because appearance is the important process. Certain surface finishes also make stainless steel easier to clean, which are important for sanitary applications. A smooth surface is obtained by polishing also provides better corrosion resistance. Surface finishes are the result of processes used in fabricating the various forms or are the result of further General process used for the manufacture of stainless steel https://www.madehow.com/images/hpm_0000_0001_0_img0192.jpg Insulation for cables: Materials used are: 1) Polyvinyl chloride (PVC) 2) Polyoxymethylene (POM) 3) Polyethylene Terephthalate (PET) 4) Polyetherethreketone (PEEK) Polyvinyl chloride: copper wire is circulated by insulating wire which is made up of poly vinyl chloride It is a thermo plastic layer and also vinyl polymer constructed of repeating vinyl groups, poly vinyl is the most common produced plastic, it is noted that nearly 40 millions of tonnes is manufactured every year. Manufacturing process: Poly vinyl is manufactured in polymerization process. Most of the common mass is chlorine which creates a given mass of PVC; due to this it requires less polymer than any other polymer. PVC has a higher density than hydrocarbon polymers, and production of chlorine has its own energy requirements , which ends up being of little practical relevance in the production of most solid objects.The most widely used process for production is suspension polymerization. , VCM and water are added into the reactor of polymerization and initiator of polymerization, along with other chemical additives, which are added to initiate the polymerization reaction ,the reaction vessel which are contented are mixed in an order to maintain the suspension and ensure a uniform particle size of the PVC resin. The reaction comes out to be exothermic, which requires a cooling mechanism this is because it has to maintain the reactor contents at the appropriate temperature. During the course of reaction,PVC slurry is degassed and stripped to remove excess VCM which is recycled into the next process, then passed though a centrifuge to remove most of the excess water. The slurry is then dried further in a hot air bed and the resulting powder sieved before storage or pelletization. In normal operations, PVC has a VCM content of less than 1 part per million, Other production processes, such as micro-suspension polymerization and emulsion polymerization, produce PVC with smaller particle sizes (10 ÃŽÂ ¼m vs. 120-150 ÃŽÂ ¼m for suspension PVC) with slightly different properties and with somewhat different sets of applications. The product of the polymerization process is unmodified PVC. Before PVC can be made into finished products, it almost always requires conversion into a compound by the incorporation of additives such as heat stabilizers, UV stabilizers, lubricants, plasticizers, processing aids, impact modifiers, thermal modifiers, fillers, flame retardants, biocides, blowing agents and smoke suppressors, and, optionally pigments. https://img.informer.com/wiki/mediawiki/thumb.php?f=PVC-polymerisation-2D.pngwidth=40 Low alloy steel: In the research it was found that the properties were similar to stain less steel and the low alloy steel used in the mouse was with same properties as used in the mouse ball. Rubber material (Coating over metal Ball) Materials used are: 1) Polyurethane 2) ABS 3) Polyester 4) Cellulose polymers(CA) 5) Polystyrene Polyurethane: Polyurethane is rubber based material which is bounded on stainless steel of the mouse, the mouse is in circle shape and that is ripped off with polyurethane Polyurethanes, are most commonly known as polycarbamates, they belong to a larger class of compounds called polymers. Polymers are macromolecules which are made up of smaller. The repeating units known as monomers, they are attached with side groups which consist of a primary long chain back bone molecule. Carbamate groups characterize the Polyurethanes (-NHCO2) in their molecular backbone. By reacting monomers in a reaction vessel, Synthetic polymers, like polyurethane, are produced In order to produce polyurethane, a stepà ¢Ã¢â€š ¬Ã¢â‚¬ also known as condensationà ¢Ã¢â€š ¬Ã¢â‚¬ reaction is performed. In this type of chemical reaction, the monomers that are present contain reacting end groups. Specifically, a diisocyanate (OCN-R-NCO) is reacted with a diol (HO-R-OH). The first step of this reaction results in the chemical linking of the two molecules leaving a reactive alcohol (OH) on one side and a reactive isocyanate (NCO) on the other. These groups react further with other monomers to form a larger, longer molecule. This is a rapid process which yields high molecular weight materials even at room temperature. Polyurethanes that have important commercial uses typically contain other functional groups in the molecule including esters, ethers, amides, or urea groups. Manufacturing process for the extraction of polyurethane https://www.niir.org/g/c/ni-173/11.jpg References: 1) Granta Design Limited, Cambridge, (2009)(www.grantadesign.com), CES EduPack User Guide 2) Ashby, M.F. (2005) Materials Selection in Mechanical Design, 3rd edition, Butterworth-Heinemann, Oxford, UK , Chapter 16. 3) https://www.gdrc.org/uem/lca/lca-define.html 4) Baer, E., Advance polymer ,Scientific American, Vol.225,No.4,Oct 1896. 5) Engineered materials Handbook ,Vol 2 , Engineering Plastics, ASM international ,Materials Park,OH,1988 6) R.J., and P. Lovell , Introduction to polymers, 2nd edition ,chapman and Hall , New York , 1991. 7) Billmeyer , F.W..Jr.,Text book of Polymer science,3rd edition, Jhon Wiley sons , New York ,1984 . Chapter 11. 8) Kingery , W.D.,H.K.Bowen ,and D.R, Uhlmann,Introduction metals, 2nd edition ,jhon Wiley sons ,New York ,1976 Chapter 14 and 15. 9) Gordon , P., principles of phase diagrams in materials systems, McGraw hill Book company new York ,1986. 10) Cambridge Engineering Selector v4,Granta Design Limited , Cambridge, UK,2005. 11) Cebon,D.Ashby,M.F. and Lee-Shothaman,L.CES Edupack 2009 users Manual , 1, Granta Design limited, Cambridge, UK,2005. 12) ABS acrylonitrile butadiene styrene On Designsite.dk, lists applications. Retrieved 27 October 2006. 13) Ed., Time-Life Books. Input/output Understanding Computers. Alexandria, VA: Time-Life Books, 1990 14) Alexander, Howard. Behold the Lowly Mouse: Clever Technology Close at Hand. 15) N.A. Hart. 2009. Course documents on sustainable design and manufacture. Available online from: https://blackboard.staffs.ac.uk/webapps/portal/frameset.jsp?tab=coursesurl=/bin/common/course.pl?course_id=_5182_ 16) copper and its uses on https://www.ganapati engineering.com [accessed on 2010] 17) Copper a vital element on https:// resources .school sciences .co.uk [accessed on 2009] 18)Why is stain less steel stain less on www.science direct.com 19) Manufacturing process of stainless steel on www.industrialmetalcasting.com/pdf/ss-mfg-process. 20) polyurethane on https://www.enotes.com/how-products-encyclopedia/polyurethane 21)Lockton, D., Harrison, D.J., Stanton, N.A. Making the user more efficient: Design for sustainable behaviour. International Journal of Sustainable Engineering Vol.1 No. 1, pp. 3-8, March 2008) https://www.danlockton.co.uk/design-for-sustainable-behaviour/ 21) 22) Journal of Occupational and Environmental Medicine: February 2010 Volume 52 Issue 2 pp 163-168 LIFE CYCLE ASSESSMENT: LCA is a holistic tool used to identify the environmental consequences of a product, process or activity through its entire life cycle and to identify opportunities for achieving environmental improvements. Life cycle stages include: ÃÆ' ¼ Raw materials acquisition, ÃÆ' ¼ Manufacturing, ÃÆ' ¼ Use/reuse. ÃÆ' ¼ Maintenance. ÃÆ' ¼ And recycling/waste management. Taking as an example the case of computer mouse an LCA involves making detailed measurements during the manufacture of the product. LCA information is to be taken into consideration is at the design stage of new products. LCA approach consists of four interrelated components: Goal definition and scoping: definition of the study purpose and objectives, identification of the product, process or activity of interest, identification of the intended end-use of study results and key assumptions employed. Inventory analysis: Identification and quantification of raw materials and energy inputs, air emissions, water effluents, solid waste, and other life-cycle inputs and outputs. Impact assessment: Qualitative and qualitative classification, characterization and valuation of impacts to ecosystems, human health and natural resources, based on the results of a life-cycle inventory. Improvement assessment: Identification and evaluation of opportunities to achieve improvements in processes that result in reduced environmental impacts, based on the results of an inventory analysis or impact assessment. LCA gives the entire cradle to grave activities of a product or process i.e from processing of raw materials to transportation, extraction, in addition to reviewing the issue of material re-use and final disposal. As a system LCA identifies processes and potential environmental burdens throughout a products life cycle. The term life cycle refers to the holistic assessment which requires the assessment of raw material production, manufacture, distribution, use and disposal including all intervening transportation steps. LCA method is one of the official methods for environmental evaluation. It recognises that every product has impact on the environment during all phases of its life and it has started a system, where each new product standard is attached with a temporary environmental annex. For in this regard life cycle assessment is a central tool. The LCA method can be divided into three basic steps Goal and scope definition Inventory analysis Impact assessment The first step in the LCA method is the goal and scope definition. For the scope the following items should be clearly described LCA is a technique that allows the comparison of the environmental impacts of materials and products. This assessment provides quantitative data to identify the potential environmental impacts of the material or product on the environment. LCA is common for assessments to be made of more limited periods eg. Cradle-to-gate and cover the entire life cycle life cycle of a material. The entire analysis is referred to as cradle-to-cradle which refers to production from extraction of raw materials, production and delivery and is often broken down into phases of lesser ambition. Goal definition and scoping is the most critical component of LCA because it provides a frame of reference for the entire study and helps define interrelationships among the other three LCA components; inventory analysis, impact assessment, and improvement assessment. The goal definition identifies the overall purpose for the LCA and its intended applications. Goal definition and scoping initiates the LCA and then drives the scope, boundary settings, data categories and data needs. This process is continuously revisited during an LCA. Scoping defines the boundaries, assumptions and limitations and should be done before an LCA is conducted to ensure that the breadth and depth of analysis are consistent with the defined goal of the LCA. Inventory Analysis: It is the most well-developed component of LCA. A completed inventory analysis provides an overview of the life-cycle inputs and outputs associated with a particular system. The results of an inventory analysis may be used to identify areas to achieve improvement, as baseline information for conducting an impact assessment or some combination of the two. This analysis gives the boundaries of the system to be studied and develop a data questionnaire to collect the appropriate data. Develops stand alone subsystem data and conduct a peer review to validate the results. ABS Acrylonitrile -butadiene-styrene is an amorphous polymer consisting of the three monomers (A,B,S) offer flexibility in which acrylonitrile provides chemical resistance, ageing resistance, hardness, rigidity, gloss and melt strength .Butadiene provides low temperature ductitlity,flexibility and melt strength. Styrene provides processing ease, gloss and hardness. The main disadvantages of ABS are its poor solvent and fatigue resistance poor UV resistance, unless protected and maximum continuous use temperature is only around 70 degree centigrade. Phenolics; Phenolic resins are obtained by polymerization and in the preparation of phenolic resins, the mode of catalysis of the resulting resin indicates the overall property characteristics. The phenolic resins have the following features: 1. These resins have excellent thermal behaviour 2. High strength level 3. Mechanical stability 4. Thermal stability 5. Low toxicity 6. Electrical and thermal insulating capabilities 7. Good cost performance characteristics 8. Low heat transfer 9. Excellent flammability performance As these properties are unique and valuable, they are among the most important thermo sets. For many years Phenolics have been used as general non reinforced thermo set plastics in applications such as electrical switches , computer peripherals etc.. These phenolic resins have high crosslink densities so they are quite brittle and have high shrinkage.