The Aurora Soil Capping study, located in northern Alberta, was constructed to evaluate reclamation practices on lean oil sands dumps. The challenges relating to its success includes determining the appropriate soil cover design(s) for the coarse textured reclamation soil, while utilizing available salvaged natural soils, some of which contain residual bitumen in the form of aggregate oil sand material (AOSM). Limited research on this material raises key questions as to the impact it will play on transport and retention processes, along with potential contamination from hydrocarbon leaching. The research conducted sought to answer these questions. This thesis describes laboratory studies conducted on four soils; the upper organic LFH layer, Bm, BC and subsoil material while varying the amount of AOSM and implementing layering schemes. Material characterization through organic carbon and particle size analysis as well as hydrophobicity studies on AOSM through contact angle analysis were performed. A tension table and pressure plates, along with columns equipped with Time Domain Reflectometry probes, were used for water retention studies. Hydraulic conductivity was measured through constant head methods. To address hydrocarbon leaching concerns, chloride tracer studies were performed and the column outflow was analyzed using Gas Chromatography to detect the hydrocarbon type and concentration. Results from water retention and hydraulic conductivity studies indicated that although the AOSM was hydrophobic, its placement at varying concentrations and forms did not create consistent significant differences in the amount of moisture retained or transported. Results from the column studies showed that under steady state and transient conditions AOSM could result in decreasing infiltration rates and increasing chloride retention. The integration of soil layers further slowed the infiltration rate and delayed chloride transport. Under saturated conditions the presence of higher concentrations of AOSM appeared to increase the rate of water movement. Although these differences were minimal, further studies are required to explore this behavior. Overall, it can be concluded that with appropriate material placement, the addition of layering schemes and hydrocarbon material, the potential exists to increase soil water content in the upper layers of the soil, thereby increasing soil water storage for plant use.

Soil water deficits greatly affect forage production. To evaluate the effects of soil moisture stress on forage production, a budgeting model was developed. The soil water budgeting model uses the initial soil water content which can be assumed or calculated. Stress was calculated as a difference between potential evapotranspiration and actual evapotranspiration at a level of - 5 bar. A radiation method was used to calculate the potential evapotranspiration and the soil water budgeting model was used to calculate the actual evapotranspiration. The Soil Conservation Service method was applied to calculate runoff and effective rainfall was calculated by subtraction of runoff from original rainfall and used in the model for calculation of actual evapotranspiration. Calculated stress was correlated to the yield and stepwise multiple regression were used to produce prediction equations. Observed soil water data and yield for calibration and validation of the models were obtained from Santa Rita Forest and Range Experimental Range in southeastern Arizona.

Thermal resistance per unit thickness for Vacuum Insulation Panel (VIP) is 5 to 10 times higher than conventional insulation materials. This makes VIP an attractive option for retrofitting exterior building envelopes. Insulation can be added in an exterior wall either on the interior side, exterior side or in the available stud cavity. VIP has high vapor diffusion resistance factor and could lead to moisture management risk in the wall layers because of the steep temperature gradient in the wall generated due to very high thermal resistance of VIP. VIP is a relatively new insulation material for building envelope construction, thus the hygrothermal or moisture management performance of VIP-insulated exterior building envelopes need to be critically analyzed before its application. This study aims to evaluate the moisture management risk associated with wood-frame stucco-cladded exterior walls retrofitted with VIP using a 2-D hygrothermal simulation tool WUFI-2D. Eight North American locations were considered, based on Moisture Index (MI) which varied between 0.13 and 1.17, and two different indoor hygrothermal loading conditions as prescribed by the ASHRAE 160P and EN 13788, respectively. The outputs from hygrothermal simulations (water content, relative humidity and temperature) were critically analysed and expressed further using freeze-thaw cycles and RHT indices. The results show that the appropriately designed VIP retrofitted walls can have superior moisture management performance as compared to conventional stucco-cladded wall. / Graduate

This thesis consists of two essays that each discuss a major component of the post-harvest management of maize in sub-Saharan Africa: drying and storage. The first essay uses cross-country data about on-farm storage decisions between 2013 and 2015 to assess the severity of storage loss in the absence of improved storage technologies. We find that while losses are low, farmers report on average that they lose more than expected and sell earlier than originally intended at harvest. Additionally, we look for evidence that farmers use adaptation strategies for the purpose of mitigating storage loss and find that storage chemicals are effective at both reducing loss and increasing storage duration. The second essay introduces a third-party moisture testing service to traders in western Kenya to elicit willingness to pay for external quality verification using two moisture detection devices, a low-cost hygrometer and a commercial grade moisture meter. We find that while traders value the moisture meter service more, the hygrometer service is more profitable for potential service providers. Further, when offered a chance to purchase the hygrometer device at/around market price ($2.50), only 15% of traders accepted the offer, suggesting that a service provider model is a viable way to make moisture testing more widely accessible and standard practice in the future.

"Susceptibility of Hot Mix Asphalt (HMA) mixes to moisture induced damage is one of the main reasons for premature failures of asphalt pavements. Hence, the evaluation of mixes for the moisture susceptibility is an essential part of the mix design. The existing methods are found to be in-sufficient to characterize mixes in terms of their moisture damage potential, and many studies have been conducted to establish an improved methodology that can better address the issue. Most of these methods involve the determination of changes in mix properties due to moisture conditioning in the laboratory or to verify the mix performance in the field or the laboratory. In the field moisture susceptible mixes are also found to lose material to extents that are dependent upon the properties of the mix and materials. So far, there has been no comprehensive study to investigate the loss of materials due to moisture induced damage. The objective of this study was to identify and evaluate a conditioning and a test method that can be used on a regular basis to detect moisture susceptible mixes and to understand the combined problem of moisture induced material loss and change in strength/stiffness of the mix. The Moisture Induced Stress Tester (MIST), Ultrasonic Pulse Velocity (UPV), Dynamic Modulus in Indirect tensile mode, and Indirect Tensile Strength (ITS) tests were utilized in the study. The effluent from the MIST was checked for the gradation of dislodged aggregates and the Dissolved Organic Carbon (DOC) content. A system dynamics (SD) approach was also adopted to investigate the problem and establish a model to reproduce field observations. The results showed that the use of MIST in combination with UPV or ITS is able to identify moisture susceptible mixes, in particular for mixes with the potential of aggregate breakdown. The mixes with a higher loss of asphalt binder during conditioning exhibit higher tensile strengths, and those with a loss of finer materials, which is indicative of aggregate breakdown, show a lower tensile strength. For the mixes used in this study, the rate of change in indirect tensile strength during moisture conditioning was found to be strongly correlated to the pre-conditioning modulus of the mix. A step-by-step framework to characterize the moisture susceptible mixes was presented."

Land-atmosphere interaction includes complex feedbacks among radiative, hydrological, and ecological processes, and the understanding of it is hindered by many factors such as the heterogeneity of land surface properties, the chaotic nature of the atmosphere, and the lack of observational data. In this study, several different methods are used to investigate the land-atmosphere interaction processes and their relationship with climate variability. Firstly, a simple one-dimensional model is developed to simulate the dominant soil-vegetation-atmosphere interaction processes in the warm climate. Although the physical processes are described coarsely, the model can be more easily used to find some relationships which may be drown out or distorted by noise. The influence of land on climate variability mainly lies in it memory, which is greatly related with the atmospheric forcing, so this model is used to investigate the influence of different forcing strengths on land-atmosphere interaction and its difference at different land covers. The findings from the simple model can provide guidance for other studies. The second part of the study compares a lagged soil moisture-precipitation (S-P) correlation (soil moisture in current day and precipitation in future 30 days) in three atmospheric reanalysis products (ERA-40, NCEP/DOE reanalysis-2, and North American Regional Reanalysis (NARR)), Global Soil Wetness Project Phase 2 (GSWP-2) data, and NCAR CAM3 simulations. Different datasets and model simulations come to a similar negative-dominant S-P correlation pattern. This is different from the traditional view that the soil moisture should have positive influence on future precipitation. Further analysis shows that this correlation pattern is not caused by the soil moisture feedback but due to the combined effect of the precipitation oscillation and the memory of soil moisture. Theoretical analysis confirms the above results and finds that the precipitation time series with the strongest oscillation at 32-60 day period is most likely to induce a significantly negative S-P correlation, and regions with longer soil water retention time are more likely to have a significantly negative S-P correlation. This study illustrates that a lagged correlation does not always indicate a causal relation.

Moisture damage in asphalt mixes refers to the loss of serviceability due to the presence of moisture. The extent of moisture damage, also called moisture susceptibility, depends on internal and external factors. The internal factors relate to the properties of the materials and the microstructure distribution, while the external factors include the environmental conditions, production and construction practices, pavement design, and traffic level. The majority of the research on moisture damage is based on the hypothesis that infiltration of surface water is the main source of moisture. Of the two other principal mechanisms of water transport, permeation of water vapor and capillary rise of subsurface water, the latter has been least explored. A laboratory test and analysis methods based on X-ray computed tomography (CT) were established to assess the capillary rise of water. The amount and size of air voids filled with water were used in the capillary rise equation to estimate the distribution of the contact angles between the water and the mastic. The results were able to show the influence of air void size on capillary rise and contact angles. The relationship between air void structure and moisture susceptibility was evaluated using a fundamental fracture model based on dissipated energy of viscoelastic materials. Detailed description is provided in this dissertation on the deduction of the model equation, the selection of the model parameters, and the required testing protocols. The model parameters were obtained using mechanical tests and surface energy measurements. The microstructure of asphalt mixes prepared in the laboratory having different air void structures was captured using X-ray CT, and image analysis techniques were used to quantify the air void structure and air void connectivity. The air void structure was found to influence the mix resistance to moisture damage. To validate the fracture model, asphalt mixes with known field performance were tested. The results demonstrated that the fracture model is an effective tool to characterize moisture susceptibility. In addition, the model showed good correlation with the reported field performance of the asphalt mixes. The findings of this study will be useful to highway engineers to evaluate asphalt mixes with alternative mix designs and internal air void structures and to estimate the rate of moisture infiltration in order to maximize the resistance of asphalt mixes to moisture damage.

The influence of climate and antecedent moisture conditions on hydrological and biogeochemical fluxes was studied and contrasted in three nested, high-elevation, snowmelt-dominated catchments in the Sierra Nevada, California and one basin-floor, semi-arid catchment in southeastern Arizona. Investigations were completed within a different two-year period at each site, with the second year being climatically different (typically drier) than the first. Spring snowmelt, widespread winter frontal precipitation, and episodic summer rains induce surface water flow in these catchments, though the timing and magnitude of nutrient redistribution among soil and stream compartments varies in each. Surface water flow from spring snowmelt in high-elevation catchments travels through the subsurface or across the surface as direct runoff A more typical process producing surface water flow in semi-arid catchments is flooding during episodic or widespread rainfall. Hydrograph separations at Emerald Lake, Topaz Lake and Marble Fork catchments in Sequoia National Park, California, revealed that the majority of snowmelt flowed through soil before entering the stream in both average and highsnow years. The Emerald Lake watershed had a higher fraction of old water in its outflow in the average accumulation year because of the previous year's high accumulation and longer melt season. A mixing model analysis performed of the upper San Pedro River, Arizona, for wet and dry years showed that summer flood hydrographs were composed mainly of precipitation and surface runoff in both years, though a higher soil-water input occurred in the wetter year and in early season floods in the dry year. Stream and soil water nitrate concentrations were higher during floods in the dry year. Early season floods in the dry year exhibited more variability in stream water nitrate and sulfate, whereas late season flood concentrations reflected a well-mixed system and therefore less variation of these species during flood hydrographs. These data showed that periods of below average precipitation preceding major runoff periods result both in less soil water and solute export during summer floods in basin-floor catchments and less direct snowmelt in high-elevation catchments. Hydrologic and solute export in each catchment, despite their differing geographical locations, responds in similar ways to climate variability.

[Truncated abstract] In southern Western Australia the replacement of deep-rooted native vegetation with annual species has resulted in rising water tables and increased salinity due to insufficient water use. The area has a Mediterranean-type climate where rainfall during summer is generally low but variable resulting in limited plant growth. However, if rainfall does occur it potentially can contribute to to the increased water excess or drainage by increasing the soil water content before the main drainage period in winter. The first study investigated factors controlling soil water content changes during the fallow (December to May) in annual farming systems. This was achieved by examining variation in available soil water storage to a depth of 1.0-1.5 m at three sites within 13 seasons. Reasons for the variation were examined using the Agricultural Production Systems Simulator (APSIM). This study also investigated the relationship between soil water content at the end of the fallow period (1 May) and the amount of drainage below 2.5 m by using APSIM coupled to historical weather records at three locations. At the end of the fallow a mean of 24 mm (or 25%) of rainfall during the fallow was retained in the soil. Losses of soil water during the fallow were due to evaporation (mean of 60 mm), transpiration from plant cover (mean of 12 mm) and drainage below the root zone and run off (combined mean of 13 mm). Soil water accumulation during the fallow period had a significant impact on simulated drainage under wheat in the following growing season. Every 1 mm increase in soil wetness at the end of the fallow resulted in a 0.7-1 mm increase in simulated drainage during the growing season. ... Variation in the water excess due to variation in rainfall was greater than the reduction in water excess due to lucerne. This makes the decisions about when to grow lucerne to reduce water excess difficult if livestock enterprises are less profitable than cropping enterprises. The findings of this PhD indicate that lucerne does have a place in Mediterranean-type environments because of its greater water use than current farming practices. However, its use needs to be strategic and the strategy will vary from region to region. For example, in the low rainfall region lucerne sowings need to be matched with high soil water contents and phase length will generally be short (2-3 years). In comparison at high rainfall regions lucerne will need to be grown for longer or combined with other strategies to increase water use.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this research was to develop a seed moisture measurement system (M.M.S.) prototype that could be embedded on a combine to harvest and analyze experimental plots. It must be able to reach the claims of seed research companies. This kind of system is trade available, though there is no technology designed in Brazil and it is imported in a high cost. To reach the aim, seven construction requirement were defined. The M.M.S. was designed and constructed obeying such requirements. Fixed frequency in 10 kHz, its operation distinguishes itself by gathering constructive characteristics capacitive sensors of parallel plates as well as concentric cylinders. Its calibration was performed using corn seeds (Zea mays L.) artificially moistened through methodology that was preliminarily developed. The calibration curve was obtained by the correlation between the sensor output voltage and the moisture seed sample. Modeling (estimated by Linear Least Squares Fitting technique and evaluated by analysis of variance) consists of three lines which delimit three reading bands (selected automatically by system). The total M.M.S. reading extends from 10 to 30 %. The system checking was comprised by comparing the prototype results to results obtained by standard oven method and three other indirect measurement methods. Thus, the prototype was achieved through the construction of a moisture measurement system that attends the construction requirements, using automatic reading temperature correction and taking into account all the conditions to be embedded on combines. / O objetivo deste trabalho foi o desenvolvimento do prot´otipo de um sistema de medi¸c ao de umidade de sementes, que possa ser embarcado em uma colhedora para colheita e an´alise de parcelas experimentais e que atenda `as necessidades das empresas de pesquisa que atuam no melhoramento de plantas. Este sistema est´a dispon´ıvel no com´ercio, por´em ´e importado a alto custo. A constru¸c ao do sistema de medi¸c ao de umidade foi feita obedecendo a alguns requisitos previamente definidos. Trabalhando com uma freq¨u encia fixa de 10 kHz, distingue-se por reunir caracter´ısticas construtivas dos sensores capacitivos de placas paralelas bem como os de cilindros conc entricos. Sua calibra¸c ao foi feita utilizando sementes de milho (Zea mays L.) umedecidas artificialmente mediante metodologia desenvolvida preliminarmente. A curva de calibra¸c ao foi obtida pela correla¸c ao da tens ao de sa´ıda do sensor com o teor de ´agua presente na amostra de sementes. O modelo (estimado pelo m´etodo de regress ao por m´ınimos-quadrados e avaliado por an´alise de vari ancia) consiste de tr es retas que delimitam tr es faixas de leitura (selecionadas automaticamente pelo sistema). A faixa capaz de medi¸c ao de umidade corresponde `a de 10 a 30 %. A aferi¸c ao do sistema foi delineada pela compara¸c ao dos resultados do prot´otipo com os resultados obtidos por um m´etodo padr ao de estufa e auxiliada por outros tr es m´etodos indiretos de medi¸c ao. Assim, a proposta de desenvolvimento do prot´otipo foi atingida atrav´es da constru- ¸c ao de um sistema de medi¸c ao de umidade que atende aos requisitos de constru¸c ao impostos, possuindo corre¸c ao autom´atica de leitura em fun¸c ao da temperatura ambiente e atendendo a todas as condi¸c oes para ser embarcado em colhedoras. / Doutor em Engenharia Mecânica