Saturday, 12 March 2011


Genetic engineering
Genetic engineering is the manipulating of a species’ genetic information so that it produces desirable characteristics.  This can be done to trees to improve the quality of the timber they produce, or how they grow. To do this, biologists take DNA from some plants with desirable characteristics and artificially inserting them into another type of tree’s DNA.

Trees can be made to resist disease by being given the traits of other trees that have natural protection to the disease. Additionally, the trees can be given natural defenses to insects. This helps production as tree growth is more efficient and results in more timber.
Trees can be made to grow faster, which has the obvious advantage of the producer being able to grow more trees in the same space of time, therefore making more money.
The forest can be better managed, for example only growing trees of a certain kind, removes the need to deforest areas that are not already replanted trees.
The timber itself can be modified so that once cut from the tree, it resists rot and wear.

It is unknown whether or not there are long term side effects of genetic modification.
The modified plants could ‘escape’ and dominate the wild population due to their enhanced characteristics.
The diseases or insects could develop counteractive traits that enhance their effectiveness.
The faster growth could mean that nutrients are not replenished in the soil quickly enough, and more water is needed than is available.

Biodegradable polymers are derived from renewable materials that are naturally degradable by micro-organisms. These micro-organisms break the large polymers into smaller less environmentally harmful molecules. As there are large numbers of them naturally occurring in landfill, the polymers will biodegrade if left there.
Biopol and PLA
They are used in packaging, disposables, plastic wrapping, coating paper and board, in agriculture for slow release pesticides, in medecine, pharmaceuticals and textiles.

They are fully degradable in the right conditions.
Semi-biodegradable polymers still remain in the environment for years.
There is a shorter time that rubbish spends in the landfill.
Needs to be sorted from recyclable plastics otherwise their resale value is damaged.
Biodegradable plastics formed from starch use carbon already within our ecosystem, rather than carbon locked up in oil.
They are not widely produced enough for them to benefit from large economies of scale.

Are not as efficient to produce as synthetics such as polypropylene.

The plastics’ degradation can still contribute to global warming due to release of carbon dioxide.

Monday, 4 October 2010

Ergonomics (Test)

Ergonomics is the designing of machines and products to be used and operated by humans. The way in which the human interacts with the product is made as easy and as comfortable for the human as possible. To help achieve this, data from anthropometrics is used.

Anthropometrics is the collection of data about the human body relating to sizes, strengths and shapes. This data is used by designers and engineers to improve the ergonomics of their product. As each human is different, anthropometrics organizes its data into distributions graphs dividing the population into percentiles, with the mean being the fiftieth percentile, and the extremes being the first and hundredth percentile.

A designer should not design for the average, because by doing so they limit their market by a great deal. By designing a product so that it is suitable for a wide range of percentiles, eg, 5-90%, the designer opens up the number of people who could buy the product enormously.

Sources of anthropometric data include “The measure of man and women” by Alvin R. Tilley and Henry Dreyfuss; and the British Standards Institute’s anthropometric charts.

Key ergonomic factors for the designer.

Predicting how humans interact with their surroundings can be done quantitatively, where statistical data about the body shape of humans and workload is used to design the product. It can also be done qualitatively, where the feelings of the user in terms of comfort and satisfaction are taken into consideration.

To cater for the wide range of human sizes, a designer can take one of four approaches. They could make a design that is applicable for everyone, such as a lift that is big enough for a wheelchair and large people. Or they could produce a range of different sizes for their design, with a specific size for small percentages of the population. They can also design a product which has built in adaptabilty, such as a desk chair, which the user can adjust to their preference. Lastly, they could design accessories to the product which aid its use by differently sized people.
The target market group (TMG) is that group of people who will or are expected to be using the product. The designer should consider this and how it effects the anthropometric data to ensure that the product is suitable. For example, if a product is to be used only by men, then their greater average size and strength should be taken into account.