Multilayer thin film silicon solar cells

New multilayer solar cells combine three innovations to produce a unique device structure which allows high efficiency cells to be designed on low quality material. The first innovation is the use of the multilayer structure itself, which provides the tolerance to low quality material. The second is the use of the well-proven buried contact technology. The third innovation is a simple technique for connecting cells in series which relies on having grooves of opposite polarity either overlapping or in close proximity to each other. These three innovations combine to produce a manufacturing approach with a small number of processing steps able to produce a product with a high energy conversion efficiency using low quality starting material. The unit of production is a large module of approximately 1 m² in area rather than the smaller 100 cm² cells which are the present commercial norm .     

GIS in planning

This paper outlines some of the potential uses of GIS in planning authorities, and identifies some of the pitfalls to be avoided. It begins with some practical considerations in the area of data sources and system configurations, goes on to envision ways in which GIS might benefit the work of a planning department, and finally considers some of the management issues which surround the introduction and use of GIS in planning.     

Marine Organisms as Indicators of Heavy Metal Pollution-Experience from 16 Years of Monitoring at a Lead Zinc Mine in Greenland

In monitoring the impact of a lead-zinc mine in Greenland, species of fish, prawns, seaweed and mussels have been analysed for cadmium, copper, lead and zinc for several years. These metals have been released to the marine environment in significant amounts from the mining operation.     

Effect of temperature on the proliferation of Gymnodinium breve and Gomphosphaeria aponina

The effect of temperature on the growth and proliferation of two marine microorganisms, the toxigenic dinoflagellate Gymnodinium breve, and a potential bio-control organism, the blue-green alga Gomphosphaeria aponina, was determined by culturing the organisms in thermal gradients established by heating and cooling the opposite ends of an aluminum bar that had been adapted to hold culture tubes. Gradients were linear and stable for the duration of each trial. There was no relationship between variations in light and growth of the organisms. Gymnodinium breve showed optimum growth at 22°C, and proliferated over a range of temperatures (17° to 30°C). Below 17°C cultures of G. breve declined in growth, and at 4°C the organisms died within 5 h. Above 31°C there was rapid decline in viability of cells, and at 33.5°C the organism died within 24 h. Gomphosphaeria aponina showed optimum growth between 24° and 29°C, with a maximum at 27°C. Growth at temperatures greater than 31°C was minimal, but the organism survived. Limitation may be due to repression of the bio-synthesis of an iron-transport compound.     

Pollution performance of firms from pulp and paper industries

The water pollution emissions by 13 of the largest pulp and paper companies, developed on the basis of monthly reports filed with the US Environmental Protection Agency (EPA) by these companies, indicate a wide disparity in the amount of pollution discharged by them into the nation's waterways. Furthermore, the net discharge of pollution in waterways by all firms is positive, which indicates that all the firms in the study pollute the nation's waterways to some degree. Information presented in this study will be useful for public issues, such as evaluating the effectiveness of the Clean Water Act, government's water pollution policy and abatement strategy, and management's effectiveness in abating water pollution.     

Removal of Mercury from Polluted Waters by the Water Hyacinth (Eichhornia crassipes)

The uptake of mercury by water hyacinth (Eichhornia crassipes) was studied in an outdoor experiment for 25 days at different metal concentrations. the removal of mercury from the water and uptake by plants was very effective during the first hours and decreased rapidly thereafter. the uptake of mercury was directly proportional to the initial concentration in the water. the highest concentrations were found in plant roots. According to the results, water hyacinth could be used for treatment of mercurial waste waters.     

Advanced manufacturing technology and work design: Towards a theoretical framework

This paper introduces a theoretical framework to guide research into the psychological effects of advanced manufacturing technology (AMT) on shopfloor operators. The framework has two main aspects. First, based on the emerging literature on the job content implications of AMT, it identifies four key constructs, namely: control, cognitive demand, production responsibility and social interaction. Second, by drawing on the more established job design, stress and related literatures, it predicts how these independent variables differentially affect system performance, job-related strain and job satisfaction. The wider implications and limitations of the theoretical framework are discussed.