Teachers have noticed that children draw only those objects which they know by name. Doubtless the adult has a similar tendency, exemplified by the researcher, to limit his observations or to relate them to that which can be expressed in the terminology of an existing or newly developed theory. In this thesis the data obtained from studies of the temperature and pressure dependence of the relative vapor pressure over moist soil samples are analyzed by a thermodynamic approach. Not all of the results can be explained completely by means of this tool. Natural systems, such as a moist soil, are probably too complex for any single theory; but since the language of thermodynamics provides the best-known means of conveying the results to others, it is felt that this language should be used throughout the thesis.

Relationship between soil moisture and the absorption of phosphorus and other nutrients.

This study focuses on how green roof thermal performance is affected by the soil moisture in summer condition. It aims to determine whether moist soil is a better insulator during the summer months than dry soil. A soil model is developed to predict simultaneous conduction, convection, and surface evaporation for a layer of moist soil representing a green roof. It used to analyze evaporation process and its affect on the soil resistance. The model considers only bare soil without vegetation on the roof. The model predicts the soil surface temperature as it is affected by soil moisture content, which can then be used to calculate heat transfer through the soil layer. An experimental dry out test was conducted to measure the soil moisture and soil temperature histories. Comparison of the predicted and measured sol surface temperature shows that the model reasonably captures the actual behavior. The evaporative cooling effectively reduces the soil surface temperature and heat flux in moist soil and can be used as an effective way to insulate the roof.

Salmonella and Cronobacter sakazakii are two leading causes of foodborne illness associated with low-moisture foods, including infant formula. Both causative organisms can persist in food manufacturing processing environments and contaminate finished product if programs are not in place to limit their introduction and control their spread. An environmental sampling and monitoring program is an important tool that food manufacturers use to determine the effectiveness of their sanitation practices and pathogen control efforts. Guidance for initiating an environmental sampling plan and evaluating the plan is lacking. The objective of this study was to develop microbiological environmental sampling plans based on the answers to a series of questions related to product hazards, processing risks and controls, and knowledge of appropriate microbiological sampling and testing protocols. Furthermore, these initial sampling plans were related to the volume of product and size of the processing facility.  An interactive spreadsheet tool for designing sampling monitoring plans for an infant formula process was developed using Microsoft Excel. Additionally, the tool can be used to record qualitative and quantitative sample test results, and to alert the user how the upcoming sampling plan will be changed, if necessary, based on monthly test summaries. The sampling tool provides a simple method for selecting an appropriate environmental sampling plan (samples per zone per month) and provides a rationale and guidance for creating and modifying these plans.  Effective sampling plans and trend analysis of sample test results support the food processors decisions for implementing controls to enhance food safety. / Master of Science in Life Sciences

Indiana University-Purdue University Indianapolis (IUPUI) / Soil moisture is a key variable in dryland ecosystems. Knowing how and to what extent soil moisture is influenced by rainfall and non-rainfall waters (e.g., dew, fog, and water vapor) is essential to understand dryland dynamics. The hyper-arid environment of the Namib Desert with its frequent occurrence of fog events provides an ideal place to conduct research on the rainfall and non-rainfall effects on soil moisture dynamics. Rainfall and soil moisture records was collected from three locations (gravel plain at Gobabeb (GPG), sand dune at Gobabeb (SDG), and gravel plain at Kleinberg (GPK)) within the Namib Desert using CS655 Water Content Reflectometer and tipping-buckets, respectively. The fog data was collected from the FogNet stations. Field observations of rainfall and soil moisture from three study sites suggested that soil moisture dynamics follow rainfall patterns at two gravel plain sites, whereas no significant relationships was observed at the sand dune site. The stochastic modeling results showed that most of soil moisture dynamics can be simulated except the rainless periods. Model sensitivity in response to different soil and vegetation parameters was investigated under diverse soil textures. Sensitivity analyses suggested that soil hygroscopic point (sh), field capacity (sfc) were two main parameters controlling the model output. Despite soil moisture dynamics can be partially explained by rainfall, soil moisture dynamics during rainless period still poorly understood. In addition, characterization of fog distribution in the Namib Desert is still lacking. To this end, nearly two years’ continuous daily records of fog were used to derive fog distribution. The results suggested that fog is able to be well - characterized by a Poisson process with two parameters (arrival rate and average depth). Field observations indicated that there is a moderate positive relationship between soil moisture and fog at GPG and the relationship tend to be less significant at the other two sites. A modified modeling results suggested that mean and general patterns of soil moisture can be captured by the modeling. This thesis is of practical importance for understanding soil moisture dynamics in response to the rainfall and fog changing conditions.

No description available.

A Dissertation submitted in fulfillment of the requirements for the degree Master of Science In the Faculty of Sciences at the University of the Witwatersrand, Johannesburg Johannesburg, January 2015 / Three methods, for the analyses of low levels of moisture in gas samples, were developed and optimized. The analytical techniques included Fourier Transform Infrared Spectroscopy (FTIR) and Pulsed Discharge Helium Ionization/Gas Chromatography (PDHID/GC). The methods included the direct analyses of moisture in gas samples using FTIR as well as the analysis of acetylene (C2H2) by FTIR and GC/PDHID. For the latter methods, the purpose was to convert the moisture in a gas sample to C2H2 by hydrolization of the calcium carbide (CaC2) with moisture to C2H2 and then analyze the resulting C2H2 content by FTIR or GC/PDHID. The C2H2 result was then converted back to moisture to obtain the moisture content of the sample. The FTIR moisture method developed provided eleven different wavenumbers for quantitation providing a wide analytical scope, specifically in complex gas matrices, where there is often peak overlap between matrix and moisture. A heated eight meter glass long path gas cell and a mercury cadmium telluride (MCT) detector were utilized. The FTIR method required much greater volumes of sample than the GC method but allowed for direct analysis of moisture without prior conversion to acetylene. Moisture permeation standards were used for calibration and the LOD’s ranged from 0.5 to 1 ppm with quantification possible from 0.5 to 10ppm. For the FTIR C2H2 method various concentration ranges were established from 50 up to 2000 ppm. Three wavenumbers were evaluated for C2H2 and methane was introduced as an internal standard. The use of methane as an internal standard provided better r2 values on the calibration data than for the tests run without internal standard. A gas chromatographic (GC), pulsed discharge helium ionization detector (PDHID) method for the determination of moisture content in small quantities of gases, based on the conversion of the moisture to acetylene (C2H2) prior to analysis, was developed. The method developed on the GC/PDHID for C2H2, provided a quantitation range from 0.6 to 7.7 ppm. Conversion of the moisture to acetylene was achieved by hydrolysing an excess of calcium carbide (CaC2) in a closed reaction vessel with a measured volume of a sample containing a known quantity of moisture. The gaseous reaction mixture was transferred, using helium (He) carrier gas, to a GC/PDHID, set up with “sample injection and heart cut to detector” to prevent matrix disturbances on the PDHID, for analysis. The acetylene concentration values thus obtained were converted back to moisture values and percentage recoveries calculated. A similar conversion process was applied on FTIR. The conversion of moisture to C2H2 using CaC2 was tested and proven to be viable. Quantification was not possible as the available sample holder could not be adequately sealed to prevent air ingress. This led to higher C2H2 values than expected. This process can be optimized by the design and production of a sealed sample holder.

Temperature and soil moisture (SM) are the two main environmental factors affecting sweetpotato growth and yield. Quantitative functional algorithms of plant growth and developmental processes under a wide range of above factors are needed for developing tools for modeling. Four experiments were conducted to quantify early and late season SM and temperature effects on sweetpotato growth, development, and physiology. In experiment I, effects of five SM levels were evaluated in a greenhouse using cultivars, Beauregard and Evangeline. Experiment II was conducted to evaluate late-season SM effects with four evapotranspiration (ET) based irrigation. In experiment III, five temperatures were imposed at early season (0-59 days after transplanting (DAT)). Late season temperature effects were evaluated with four day/night temperatures from 17 to 91 DAT, in experiment IV. Experiments II, III, and IV were conducted in soil plant atmosphere research facility using Beauregard. Growth, developmental, and physiological parameters were measured. Rate of storage root (SR) development of both cultivars showed a quadratic decline with decreasing SM. Soil moisture optima for SR initiation were 0.168 and 0.199 m3 m-3, equivalent to 63 and 75% field capacity (FC), for cultivars Beauregard and Evangeline, respectively. Shoot biomass declined more rapidly than root with declining SM. Results revealed that, maintaining SM closer to FC during early season is beneficial for early development of root and shoot. Storage root biomass declined quadratically with declining irrigation. The optimum irrigation was 72% of ET and less biomass was partitioned to SRs above that level. Early season temperature study revealed, SR conversion efficiency increased quadratically and reached optimum at 23.9°C with increasing temperature. Maximum rate of SR initiation was reached at 29.5°C in 16.7 d. Biomass partitioned to roots declined linearly with increasing temperature. The SR production efficiency declined from 0.43 to 0.08 g SR kg-1 total weight, and dropped by 81% relative to optimum temperature. The SR fresh weight at high temperature declined 99% relative to optimum temperature. High temperature during mid- and late-seasons partitioned more biomass to shoots, less to roots lowering SR yield. The functional algorithms developed are vital to make management decisions and to develop crop models.

Chip and scrub seal treatments are one of the most common pavement preservation practices, however, no performance specifications exist in Mississippi. Review of literature has shown the treatment of cores being successful in reducing the viscosity of aged asphalt pavements. The purpose of this thesis is to provide a basis for performance based specifications for surface treatments in Mississippi. This thesis provides information pertaining to viscosity, moisture loss, and frosted marble analysis of emulsions and the effects of rejuvenation after application of emulsions to aged asphalt pavements which are vital to the performance of the surface treatment. The objectives to this thesis are to determine and evaluate the effects of rejuvenation, frosted marble test, and moisture loss of emulsion applied to aged asphalt pavements. Results from these analysis’ are favorable for developing or providing a basis for performance based specifications for surface treatments applied in Mississippi.

Loss of ammonia from broiler litter degrades air quality, decreases litter fertilizer value, and can have negative health consequences for birds and their caretakers. Rates of NH3 emission from broiler houses are complicated by interrelated management and environmental factors such as air temperature, humidity, house style, ventilation rate,bird age, litter conditions, litter characteristics, and cleanout schedule. Wide variations inemission rates necessitate further investigation of litter characteristics and abatement techniques. The research was designed to clarify the impact of moisture effects that are critical to emissions for poultry litter, in conjunction with bedding type and temperature. Experiments were conducted on litter samples in the laboratory using anacid trap method for determining NH3 losses. Statistical models were developed for predicting release from each bedding material and within the range of litter moistureand temperatures found in commercial broiler houses. This allowed development of relationships that describe the effects of bedding, moisture, time, and temperature on litter generation that have not been published previously. First, type of bedding material was investigated within a limited scope of moisture contents. The results indicated that increasing moisture increases generation from litter. Literature supports the phenomenon that greater litter moisture content up to apoint elicits greater release. At the original moisture content, sand and vermiculite litters generated the most, whereas wood shavings, commercial, and rice hull. Second, an extended range of litter moisture contents (20 – 55%) was investigated while including temperature (18.3 – 40.6 °C) effects. Experiments were conducted using built-up commercial broiler litter from multiple flocks. Response surfaces were parabolic cylinders, indicating maximum production was between 37.4 and 51.5% litter moisture depending on temperature. Comparing the temperature extremes, the maximum up to 7 times greater at 40.6 vs. 18.3 °C. This research defines intermediate critical moisture levels in broiler litter where NH3 is maximized, providing target areasfor researchers and the poultry industry to develop management scenarios to reduce from litter.