In an engineering context the precautionary principle is often perceived as an excuse to do nothing or a substantial barrier to technical progress. The precautionary principle requires that remedial measures be taken in situations of scientific uncertainty where evidence of harm cannot be proven but potential damage to human or environmental health is significant. In this paper the scope of the...

Recycling reduces the total number of trees that are cut down to make paper and can reduce overall demand for wood. But more importantly, paper recycling saves forests. By substituting used paper for trees, recycling reduces the overall intensity of forest management needed to meet a given demand for paper, and the pressure to convert natural forests and ecologically sensitive areas like wetlan...

Australia is facing serious challenges in the management of water in various urban and regional locations. Two popular responses to these challenges are increasing supply through alternative water sources such as recycled and desalinated water. However, significant gaps exist in our knowledge of community attitudes to these alternative sources of water, particularly for potable use. This paper ...

(1) Potential uses of photosynthetie bacteria in the recycling of human wastes have been considered. I t is concluded that systems using photosynthetic bacteria may have advantages over purely algal systems under conditions where total recycling is needed and energy is not abundant. (2) Two systems are proposed in which the metabolic potential of the photosynthetic bacteria might be realized. B...

(1) Potential uses of photosynthetie bacteria in the recycling of human wastes have been considered. I t is concluded that systems using photosynthetic bacteria may have advantages over purely algal systems under conditions where total recycling is needed and energy is not abundant. (2) Two systems are proposed in which the metabolic potential of the photosynthetic bacteria might be realized. B...

(1) Potential uses of photosynthetie bacteria in the recycling of human wastes have been considered. I t is concluded that systems using photosynthetic bacteria may have advantages over purely algal systems under conditions where total recycling is needed and energy is not abundant. (2) Two systems are proposed in which the metabolic potential of the photosynthetic bacteria might be realized. B...

Bottle grade virgin PET (polyethylene terephthalate) resin was investigated through five consecutive injection molding steps to simulate recycling cycles. Tests were carried out after each recycling to evaluate degradation, crystallinity (by density and Differential Scanning CalorimetryDSC measurements), hardness, and tensile and flexural properties. Consecutive recycling resulted in cumulative...

(1) Potential uses of photosynthetie bacteria in the recycling of human wastes have been considered. I t is concluded that systems using photosynthetic bacteria may have advantages over purely algal systems under conditions where total recycling is needed and energy is not abundant. (2) Two systems are proposed in which the metabolic potential of the photosynthetic bacteria might be realized. B...

The cell-free biocatalytic production of fine chemicals by oxidoreductases has continuously grown over the past years. Since especially dehydrogenases depend on the stoichiometric use of nicotinamide pyridine cofactors, an integrated efficient recycling system is crucial to allow process operation under economic conditions. Lately, the variety of cofactors for biocatalysis was broadened by the ...

Why recycle? The most commonly stated reason for recycling is to reduce burdens associated with the disposal of our never-ending stream of wastes. Waste disposal potentially causes air and water pollution and is costly; moreover, landfi lls compete with other land uses. In addition, recycling can extend our supply of materials to alleviate scarcity and to moderate rising prices of raw materials...