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Moisture measurements play an important role in many material preparations and industrial processes. Microwave techniques have been used for several decades for such measurements. Shortcomings associated with the method have been addressed. Graphical solutions used hitherto to obtain the permittivity from waveguide measurements have been replaced by computer programs. The accuracy of measurement have been improved by the development of waveguide standards and the implementation of calibration procedures. Permittivity measurements in through and short circuited rectangular waveguides are reported on a wide range of solid, granular and liquid materials important to the food industry. Techniques to suppress standing wave effects have enabled accurate plane wave measurements of permittivity. For bulk materials, new measurement probes have been developed for on line measurements and associated with these probes lower cost instrumentation has been considered. The· main outcome of the study is the improvement in permittivity measurements of sample quantities of material. Moisture measurements in bulk materials have been facilitated by novel non invasive probes.

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ABSTRACT The TDR measures soil water content by measuring the travel time of an electromagnetic step pulse through a wave guide embedded in the soil. Damage during insertion and retrieval of the probe makes it unsuitable for repeated use. A multilevel-TDR probe with adequate protection for cable was designed and tested to overcome this problem. Each section of the multilevel-TDR probe was constructed by embedding a 60 mm centre rod and a 63 mm outer loop in grooves on the outer wall of a 200 mm section of PVC pipe. Fifteen such probes were tested in the laboratory and the field by comparing it with the weighing method. Regression analysis between TDR-ϴv and weighing method-ϴv showed good correlation with an R2 of 0.97 and 0.98 during two laboratory experiments and 0.51 during the field experiment. This multilevel probe is cost effective, reusable and can measure soil water content at different depths.

ABSTRACT The TDR measures soil water content by measuring the travel time of an electromagnetic step pulse through a wave guide embedded in the soil. Damage during insertion and retrieval of the probe makes it unsuitable for repeated use. A multilevel-TDR probe with adequate protection for cable was designed and tested to overcome this problem. Each section of the multilevel-TDR probe was constructed by embedding a 60 mm centre rod and a 63 mm outer loop in grooves on the outer wall of a 200 mm section of PVC pipe. Fifteen such probes were tested in the laboratory and the field by comparing it with the weighing method. Regression analysis between TDR-ϴv and weighing method-ϴv showed good correlation with an R2 of 0.97 and 0.98 during two laboratory experiments and 0.51 during the field experiment. This multilevel probe is cost effective, reusable and can measure soil water content at different depths.

This research investigated the impact of sludge type, polymer type (percent mole charge), dosage, mixing rate, and solution ionic strength on bound water content of sludge flocs. Data determined to evaluate the extent of dewatering included: percent dry solids, bulk density, bound water content (determined by dilatometric method), floc density (determined by isopycnic centrifugation), and cake solids concentrations. Calculated floc densities and bound water contents were compared with measured values. The polymer mole charge had marginal impact on bound water content. The optimal polymer dose as determined by dose curves did not necessarily result in the least bound water content. The mixing rate did not have an impact on bound water content of the chemical sludge, but did have an impact on bound water content of the biological sludge. However, the percentage of total water removed that was due to bound water removal was not affected by rate of mixing, polymer mole charge, or polymer dose. Altering solution ionic strength did not appear to improve bound water removal. The calculated bound water content values determined using measured floc densities were consistently greater than the measured bound water content values determined by dilatometric method. The bound water content per the dilatometric method did not account for all the water present in the floes as determined by the isopycnic centrifugation method. / Master of Science

This paper describes how water content reflectometers (WCRs) were analyzed to develop a calibration equation. Time domain reflectometry (TDR) technique is the most prevalent method in in-situ moisture monitoring; and WCR is a type of low frequency TDR sensors, which is sensitive to soil type. Developing soil-specific calibration and investigating different environmental effects on WCR calibration is important. This study focused on investigation of the soil dry density and temperature effects on WCR calibration in RMA soil. Two series of tests to develop soil-specific calibration with dry density and temperature offset were conducted. Results from testing program showed that WCR response was positive related to volumetric water content, dry density, and temperature. Equations were developed to illustrate the response-density-temperature-moisture relation. Application to a field site was also presented to illustrate the difference in volumetric water contents obtained by using manufacturer method and the calibration procedure drawn in this paper. / text

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For this research, the abnormality of tissue cultured plantlets,vitrification, was examined in Gypsophila paniculata.Measurement of the relative water content and water saturation deficit of plantlets in culture revealed that vitrified plantlets contain relatively more water and less air spaces than non-vitrified plantlets.The effect of relative humidity on vitrification and growth was investigated using a variety of methods.From the results found, it was determined the defining characteristic of vitrified plantlets is water filled intercellular spaces. It was also determined that the primary cause of vitrification is high relative humidity resulting in a lack of transpiration in vitro but that other factors such as unbalanced mineral nutrition or high medium cytokinin can exacerbate vitrification.Further research in tissue culture may investigate the influence of relative humidity on plant growth and morphology, the mechanism by which plants exclude water from their intercellular spaces and refine in vitro tissue mineral analysis as a means by which critical mineral concentrations can be determined. / Doctor of Philosophy (PhD)