Digital Commons Network^™

Alternative And Renewable Energy, Emil Opitz

Undergraduate Theses and Senior Projects

The world is going to run out of fossil fuels in the near future. An estimated one to two trillion barrels of oil is believed recoverable using today’s technologies. This amount of oil will last the world no more than 70 years, and perhaps only half that long. A system of alternative and renewable fuels is our only solution to this problem. With proper action and development, a worldwide energy crisis will be avoided.

We have an abundance of renewable and alternative energy sources that are not currently being used, enough to supply almost all of our energy needs. Wind …

Multiple Mixed-Type Attractors In A Competition Model, J. M. Cushing, Shandelle M. Henson, Chantel C. Blackburn

Faculty Publications

We show that a discrete-time, two-species competition model with Ricker (exponential) nonlinearities can exhibit multiple mixed-type attractors. By this is meant dynamic scenarios in which there are simultaneously present both coexistence attractors (in which both species are present) and exclusion attractors (in which one species is absent). Recent studies have investigated the inclusion of life-cycle stages in competition models as a casual mechanism for the existence of these kinds of multiple attractors. In this paper we investigate the role of nonlinearities in competition models without life-cycle stages. © 2007 Taylor & Francis Group, LLC.

Soil Fertility And Productivity Relationships In Rice Production System, Bangladesh, S Rahman, Rj Parkinson

School of Geography, Earth and Environmental Sciences

This paper presents an econometric analysis of the influence of soil fertility status on productivity and resource use in rice production utilizing survey data from 21 villages in three agro-ecological regions of Bangladesh. Detailed crop husbandry input-output data were collected from 380 paddy rice (Oryza sativa) farmers. Data collected included fertilizer, pesticide, labour, animal power services, irrigation, farm capital assets and rice yield. The soil fertility status in each region was determined by analysis of soil organic carbon, available nitrogen, phosphorus and potassium concentration. Analysis was based on a profit function, where the selected soil fertility parameters were incorporated as …

Socio-Economic Aspects Of Commercial Ports And Wharves In Southwest England: A Grounded Theory Approach To Regional Competitiveness, Sarah Tuck

Plymouth Business School Theses

The Southwest Region, as defined by the SW Regional Development Agency, forms an extended peninsula with a coastline of 1,020 km, the longest of any region in England. All along this coastline are fishing ports, commercial ports, small wharves, closed ports, ferry ports and leisure ports. Amongst the smallest are a dozen tidal ports, tiny harbours and rocky wharfs that still maintain a commercial trade of local and environmental significance. According to most theories of port development these ports should close, being forced out of business by larger, more efficient ports. Semi-structured interviews were conducted with fifteen people who were …