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The need for an improved control strategy for the operation of a wind-powered refrigeration system for the storage of apples was investigated. The results are applicable to other systems which employ intermittently available power sources, battery and thermal storage, and an auxiliary, direct current power supply. Tests were conducted on the wind-powered refrigeration system at the Virginia Polytechnic Institute and State University Horticulture Research Farm in Blacksburg, Virginia. Tests were conducted on the individual components of the system. In situ windmill performance were also conducted. The results of these tests have been presented. An improved control strategy was developed to improve the utilization of available wind energy and to reduce the need for electrical energy from an external source while maintaining an adequate apple storage environment. Ph. D.

Metadata only record Within the last thirty years in the West African Sahel, farmers have started to implement agroenvironmental practices which have allowed them to improve the soil quality and increase crop yields. Using two examples of land rehabilitation in Africa, this paper examines the technical and institutional innovations and their impacts on the ability to meet food demand for the growing population. Agroenvironmental techniques incorporate trees into the agricultural landscape, which improves water retention in the soil, increases the supply of nutrients, reduces wind erosion, and provides other marketable tree products. This large-scale effort has created income opportunities for farmers, benefited women, and increased food supply for many African families.

This presentation gives an overview of the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program (SANREM CRSP). The SANREM CRSP utilizes a systems approach to promote many goals including the improvement of agricultural productivity, the empowerment of smallholders, and the promotion of sustainable development. This presentation shows the different components, partners, and structure of the SANREM CRSP, the extent of capacity building efforts, and the long-term research activities for Phase IV. ME (Management Entity)

Many electric utilities have been tapping such energy sources as wind energy or conservation for years. However, the literature shows few attempts to incorporate such non-dispatchable energy sources as decision variables into the long-range planning methodology. In this dissertation, efficient algorithms for electric utility capacity expansion planning with renewable energy are developed. The algorithms include a deterministic phase which quickly finds a near-optimal expansion plan using derating and a linearized approximation to the time-dependent availability of non-dispatchable energy sources. A probabilistic second phase needs comparatively few computer-time consuming probabilistic simulation iterations to modify this solution towards the optimal expansion plan. For the deterministic first phase, two algorithms, based on a Lagrangian Dual decomposition and a Generalized Benders Decomposition, are developed. The Lagrangian Dual formulation results in a subproblem which can be separated into single-year plantmix problems that are easily solved using a breakeven analysis. The probabilistic second phase uses a Generalized Benders Decomposition approach. A depth-first Branch and Bound algorithm is superimposed on the two-phase algorithm if conventional equipment types are only available in discrete sizes. In this context, computer time savings accrued through the application of the two-phase method are crucial. Extensive computational tests of the algorithms are reported. Among the deterministic algorithms, the one based on Lagrangian Duality proves fastest. The two-phase approach is shown to save up to 80 percent in computing time as compared to a purely probabilistic algorithm. The algorithms are applied to determine the optimal expansion plan for the Tijuana-Mexicali subsystem of the Mexican electric utility system. A strong recommendation to push conservation programs in the desert city of Mexicali I results from this implementation. Ph. D.

This paper explores the elements that lead communities to take action to protect ecosystem health. The operating assumption has been that the provision of information would be the essential ingredient in spurring communities to protect natural resources.

Metadata only record Adapting to Change in the Andean Highlands: Practices and Strategies to Address Climate and Market Risks in Vulnerable Agro-ecosystems (SANREM CRSP LTRA 4) focus is to identify the consequences of climate change for one of the poorest and most vulnerable regions in the Western Hemisphere and develop adaptive capacities. The project uses a cross disciplinary and participatory approach, linking biophysical and social sciences research with local knowledge systems through participatory institutions. The presentations concentrate on some of the key findings in the context of climate change. In the biophysical sciences Anji Seth will report on Altiplano climate change projections for this century; Peter Motavalli on the mitigation and adaptation aspects of organic soil amendment practices in rural communities; and Karen Garrett on anticipating and responding to plant disease and pests risks. Finally, Valdivia and Gilles will discuss findings on strategies for enhancing the adaptive capacity of small Andean producers. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

Metadata only record This special issue includes 12 articles dedicated to exploring some of the complex political and socio-economic issues related to climate change. The articles stress that climate change issues are highly politicized, difficult to determine accurately in scope and impact, and not seen as a demanding issue for poor communities. The connections between gender and poverty must be considered in negotiation processes in order to minimize climate change threats.

Many believe that they can achieve the cornucopian dream by getting to a certain place, such as the United States, where others may be appearing to live the dream, even though all evidence shows that the Industrial age and all of its benefits are ending. The era of cheap oil that fueled the Industrial Revolution, which made an abundance of material goods and food possible, is now coming to an end, and humankind has delayed preparing for the post-industrial world for too long. Supplementary information is included in a separate file

Transition is an important phenomenon in large scale, commercial, wind tunnel testing at low speeds because it is an excellent indicator of an airfoil performance. It is difficult to estimate transition through numerical techniques because of the complex nature of viscous flow. Therefore experimental techniques can be essential. Over the transition region the rate of heat transfer shows significant increases which can be detected using infrared thermography. This technique has been used predominantly at high speeds, on small models made of insulated materials, and for short test runs. Large scale testing has not been widely undertaken because the high sensitivity of transition to external factors makes it difficult to detect. The present study records the process undertaken to develop, implement and validate a transition detection system for continual use in the Virginia Tech Stability Wind Tunnel: a low speed, commercial wind tunnel where large, aluminium models are tested. The final system developed comprises of two high resolution FLIR A655sc infrared cameras; four 63.5-mm diameter circular windows; aluminium models covered in 0.8-mm silicone rubber insulation and a top layer of ConTact© paper; and a series of 25.4-mm wide rubber silicone fiberglass insulated heaters mounted inside the model and controlled externally by experimenters. This system produces images or videos of the model and the associated transition location, which is later extracted through image processing methods to give a final transition location in percentage chord. The system was validated using two DU96-W-180 airfoils of different chord lengths in the Virginia Tech Stability Wind Tunnel, each tested two months apart. The system proved to be robust and efficient, while not affecting the airfoil performance or any other system in use in the wind tunnel. Transition results produced by the system were compared to measurements obtained from pressure data and stethoscope tests as well as the numerical predictions of XFOIL. The transition results from all four methods showed excellent agreement with each other for the two models, for at least two Reynolds numbers and for several angles of attack on both suction and pressure side of the model. The agreement of data obtained under such different conditions and at different times suggests that the infrared thermography system efficiently and accurately detects transition for large aluminium models at low speeds. Master of Science

In this issue we cover the topic on education and advocacy on natural resources management. This was identified by the Working Group No. 2 led by Ms. Dulce Elazegui of ISPPS-UPLB during the Policy Workshop on the First Bukidnon NRM Policy Forum, 8-9 November 2001, Valencia City.