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Title
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Do changes in maize prices and input prices affect smallholder farmers' soil fertility management decisions? : panel survey evidence from Kenya
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Creator
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Olson, David William
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Date
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2018
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Collection
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Electronic Theses & Dissertations
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Description
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Soil degradation, low cereal yields, and poor yield response to inorganic fertilizer are serious problems in many parts of sub-Saharan Africa (SSA), including Kenya. Soil fertility management (SFM) practices such as maize-legume intercropping and organic fertilizer use, particularly when used jointly with inorganic fertilizer, have the potential to increase yields and yield response to inorganic fertilizer and improve soil health. However, relatively little is known about the drivers of...
Show moreSoil degradation, low cereal yields, and poor yield response to inorganic fertilizer are serious problems in many parts of sub-Saharan Africa (SSA), including Kenya. Soil fertility management (SFM) practices such as maize-legume intercropping and organic fertilizer use, particularly when used jointly with inorganic fertilizer, have the potential to increase yields and yield response to inorganic fertilizer and improve soil health. However, relatively little is known about the drivers of adoption of such SFM practices, including their joint use. Moreover, it is often suggested that African farmers will respond to an increase in the maize price they expect to receive at the next harvest by increasing investment in their soils or that they might alter their use of SFM practices in response to changes in input prices. Yet previous studies largely ignore the role of such prices. Using nationwide household panel survey data from Kenya, we first predict the maize price a household can expect to receive at the upcoming harvest based on observables at the time they make SFM decisions; we then estimate the effects of changes in this predicted maize price and input prices on household adoption decisions for individual SFM practices and combinations thereof. Likely due to multiple market failures, we find that Kenyan smallholders’ SFM adoption decisions are largely insensitive to changes in prices; however, there is some evidence that they are more likely to use organic fertilizer and use less inorganic fertilizer per acre when inorganic fertilizer prices rise.
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Title
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The design, development, fabrication and testing of a 100 watt skutterudite thermoelectric generator
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Creator
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Lyle, Matthew
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Date
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2011
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Collection
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Electronic Theses & Dissertations
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Description
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Thermoelectric technology is a method of renewable, alternative energy that utilizes the Seebeck effect to convert some of the thermal energy in a temperature gradient to electricity. The optimal temperature range for skutterudite thermoelectric devices is around 650°C, making them ideal for high temperature applications. At this temperature range, the skutterudite thermoelectrics have a device-level conversion efficiency of about 9%. As these devices are still in the development stage,...
Show moreThermoelectric technology is a method of renewable, alternative energy that utilizes the Seebeck effect to convert some of the thermal energy in a temperature gradient to electricity. The optimal temperature range for skutterudite thermoelectric devices is around 650°C, making them ideal for high temperature applications. At this temperature range, the skutterudite thermoelectrics have a device-level conversion efficiency of about 9%. As these devices are still in the development stage, testing that simulates real-world conditions is necessary to assess the feasibility of implementing skutterudite thermoelectric technology with current processes. A standardized procedure to test the skutterudite thermoelectric devices has been established to reduce variability in device fabrication and generator assembly. This procedure includes a measurement and tracking system to aid in establishing relationships between component properties and thermoelectric performance. In addition, a technology has been developed to electrically bypass any failed devices to preserve overall power generation.Results indicate that additional efforts are needed to address the high level of thermal stresses the devices experience during operation. Several methods to reduce thermal stresses and investigate potential stressors are proposed. In addition, the successful performance of the electrical bypass technology suggests that it is indeed a viable method of bypassing individual devices for experimental tests. Additional testing and improvements can be made as necessary to implement this technology in the envisioned 1 kW skutterudite thermoelectric generator.
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