Master of Science / Department of Biological & Agricultural Engineering / Ajay Sharda / Moisture measurement is critical when baling alfalfa into round bales for feed. If alfalfa is too wet or too dry, it can greatly diminish the alfalfa crop’s feed quality and cause economic loss to producers. Therefore, monitoring of alfalfa moisture content while baling is critical for producers to maintain hay quality and maximize profits. Currently, there are several different types of moisture sensing technologies available for round balers. But, concerns exist regarding their accuracy and repeatability during hay baling. Therefore, objectives of this project are to 1) Establish a protocol for coring methodology to assess the variation of moisture within a round alfalfa hay bale, and 2) Compare and contrast sensing accuracy and repeatability of different hay moisture sensing technologies. A coring methodology was established to determine the average moisture within a round bale based upon the way a sensor in a round baler chamber would determine the bale moisture; by looking at the moisture contents along the round bale diameter. This method was then compared with the more traditional method of using radial cores only to determine the whole bale moisture content. A sensor testing stand was developed to perform comparative testing between the sensors on the same alfalfa hay bale and collect core samples of material immediately after it was formed. Six commercially available moisture sensors were selected to measure moisture at four pre-determined locations on hay bales. After the sensor measurements, core samples were extracted from the exact same locations to determine actual moisture using oven-drying method. The moisture measurements were conducted during three growth stages and bales were formed with three approximate moisture contents of 10%, 15% and 20%. Six different cuts of alfalfa of the same variety were used to capture all the measurements. A seventh cut was also performed for moisture measurements with the alfalfa baled at 15% and the same growth stage, but different baler compression cylinder pressures (250, 400, and 800psi). Actual moisture content was across different sampling locations were compared to understand moisture distribution and establish coring protocol. Sensor and oven-dried measurements were compared to determine accuracy and repeatability of sensing technologies. Results showed that sensors and oven-dried measurement varied for all the sensors for every growth stage and baling moisture levels, with one sensor exhibiting lowest variability in its readings. The comparison identified the most accurate and reliable sensor among the ones currently available. A second year of testing was also conducted to validate the research from the first year of testing. Future research needs to be conducted to identify correlation between the testing stand readings and actual hay baler moisture sensor readings.

No description available.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Tracy DeLiberty, Dept. of Geography. Includes bibliographical references.

Proton exchange membrane (PEM) fuel cells, with low operating temperatures and high power density, are a reasonable candidate for use in mobile power generation. One large drawback to their use is that their fuel reformer requires not only fuel but also water, thereby requiring two separate reservoirs to be available. PEM fuel cells exhaust enough water in their oxidant stream to potentially meet the needs of the fuel reformer. If this water could be recovered and routed to the fuel reformer it would markedly increase the portability of PEM fuel cells. The goal of this research was to test a previously designed axial flow moisture separator. The separator was employed in a test bed which utilized compressed, heated air mixed with steam to simulate the oxidant exhaust conditions of a 25 kW PEM fuel cell. The simulated exhaust was saturated with water. The mixture was expanded through the turbine side of an automotive turbocharger, which dropped the temperature and pressure of the mixture, causing water to condense, making it available for separation. The humid air mixture was passed over an axial flow centrifugal separator and water was removed from the flow. The separator was tested in a variety of conditions with and without passing chilled water through the separator. The axial separator was tested independently, with a flow straightener preceding it, and with a commercially available centrifugal moisture separator in series following it. It was shown that cooling makes a significant impact on the separation rate while adding a flow straightener does not. Separation efficiencies of 19% on average were experienced without cooling, while efficiencies of 50% were experienced with 3.1 kW of cooling. The separation efficiency of the two moisture separators combined was found to be 31.7% which is 165% that of the axial separator alone under uncooled conditions.

Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

A new experimental approach to determine the hydraulic characteristics of unsaturated soils using a centrifuge permeameter was developed in this study. Specifically, the centrifuge permeameter is used to determine the water retention curve (WRC), which quantifies the energy required to retain water in the soil pores during wetting and drying, and the hydraulic conductivity function (K-function), which quantifies the soil's change in impedance to water flow as it becomes unsaturated. An aim of this study is the promotion of using experimentally-derived hydraulic characteristics in engineering practice. Accordingly, the goals behind development of the centrifuge permeameter were a reasonable testing time, measurement of all variables relevant to water flow in unsaturated soils, and a methodology allowing straightforward interpretation of experimental data to determine the hydraulic characteristics. Development of the centrifuge permeameter was guided by lessons learned from an evaluation of previous characterization approaches. Specifically, issues such as the use of steady-state or transient water flow, boundary condition effects, and the use of instrumentation were evaluated in conventional tests to better develop the centrifuge permeameter. Steady-state infiltration of water through a soil specimen instrumented with tensiometers to measure matric suction and time domain reflectometry to infer moisture content was found to be the most reliable means of characterization. Steady-state water flow permits straightforward, repeatable interpretation of instrumentation results, boundary conditions, and flow data to determine the hydraulic characteristics. Centrifugation is employed to decrease the time required to reach steady-state water flow through a soil specimen by imposing a centripetal acceleration on the infiltrating water. The water infiltration rate and centripetal acceleration can be independently controlled in the centrifuge permeameter in order to reach different target hydraulic conductivity values. Continuous, in-flight measurement of the variables relevant to hydraulic characterization is possible through an on-board data acquisition system. The experimental component of this study is focused on validation of the centrifuge permeameter and verification of the hydraulic characteristics obtained using this approach. Simultaneous determination of the WRC and K-function for a clay of low plasticity was found to be possible in less than a week using the centrifuge permeameter, whereas several months were required in conventional tests. Consistent measurements of hydraulic conductivity were obtained using this approach, and little hysteresis was observed in the hydraulic characteristics. Additional experiments were performed to evaluate the validity of different assumptions required to interpret the experimental data and different issues in centrifuge testing. Two major assumptions required in previous centrifuge permeameter approaches were evaluated using the instrumentation available in the centrifuge permeameter. During steady-state water flow in the centrifuge, the suction and moisture content were found to be relatively uniform along the longitudinal axis of the permeameter, and the outflow boundary was found to have a negligible influence on the suction profile. Settlement under the increased body forces in the centrifuge were found to be negligible for the soil investigated in this study. The hydraulic characteristics were found to be sensitive to the calibration of the transducers and sensors used to infer the water pressure and moisture content during centrifugation. Overall, the expeditious, direct determination of the hydraulic characteristics of unsaturated soils was successfully achieved using centrifuge technology. Accordingly, the centrifuge permeameter approach helps promote the use hydraulic characteristics of unsaturated soils in geotechnical engineering design.

No description available.

Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 1982. / Includes bibliographical references (leaves 118-125).

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 127-137).

Thesis (M. Sc. Agr.)--University of Sydney, 1999. / Title from title screen (viewed Apr. 21, 2008). Submitted in fulfilment of the requirements for the degree of Master of Science in Agriculture to the Dept. of Agricultural Chemistry & Soil Science, Faculty of Agriculture. Includes bibliography. Also available in print form.