The objective of this study was to determine how the key features of bioreactor landfills; increased temperature, moisture and microbial activity, affect the biological stability of the landfill material. In the first part of the study the solubilization and degradation of lignin in paper exposed to these bioreactor landfill conditions are explored. The solubility of the lignin in paper was observed at different temperatures and over 27 weeks at 55°C and the anaerobic bioconversion of office paper, cardboard and Kraft lignin was observed in bench-scale reactors over 8 weeks. As the temperature rose, lignin solubility increased exponentially. With extended thermal treatment, the dissolution of lignin continues at a constant rate. This rate increases 15 times for paper and 1.5 times for cardboard in the presence of rumen inoculum compared to un-inoculated systems. At around 6 weeks the inter-monomeric linkages between the solubilized lignin molecules began breaking down, releasing monomers. In cardboard and Kraft lignin, a significant amount of the monomers mineralize to CO₂ and CH₄ during this time period. The results indicate that small, but significant rates of lignin solubilization and anaerobic lignin degradation are likely to occur in bioreactor landfills due to both higher temperature and microbial activity. In the second part of the study, field data from the Outer Loop Recycling and Disposal Facility in Louisville, Kentucky was evaluated to determine the effectiveness of an anaerobic-aerobic landfill bioreactor (AALB) vs. the control landfill that is managed as a traditional landfill. Moisture, temperature, elevation and the amount of time the MSW has spent in the landfills (age) were measured and compared to determine the factors that affect the biological stability of the landfill. The results showed that the MSW in the AALB is more biologically stable than the MSW in the control landfill, indicating that they are more degraded. Additionally, elevation or location of the MSW was the key factor in determining the extent of MSW stability within the AALB and temperature is the key factor in determining the biological stability of the MSW in the control landfill. Higher temperatures correlated with a more biologically stable waste. The cellulose to lignin ratio (C/L ratio) and biochemical methane potential (BMP) were the main biological stability parameters used. / Master of Science

Passenger car equivalents (PCEs) are used in highway capacity analysis to convert a mixed vehicle flow into an equivalent passenger car flow. This calculation is relevant to capacity and level of service determination, lane requirements, and determining the effect of traffic on highway operations. The most recent Highway Capacity Manual 2000 reports PCEs for basic freeway segments according to percent and length of grade and proportion of heavy vehicles. Heavy vehicles are considered to be either of two categories: trucks and buses or RVs. For trucks and buses, PCEs are reported for a typical truck with a weight to power ratio between 76.1 and 90.4 kg/kW (125 and 150 lb/hp). The weight to power ratio is an indicator of vehicle performance. Recent development of vehicle dynamics models make it possible to define PCEs for trucks with a wider variety of weight to power ratios. PCEs were calculated from the relative impact of trucks on traffic density using the simulation model INTEGRATION. The scope of this research was to evaluate PCEs for basic freeway segments for trucks with a broader range of weight to power ratios. Such results should make freeway capacity analysis more accurate for mixed vehicle flow with a non-typical truck population. In addition, the effect of high proportion of trucks, pavement type and condition, truck aerodynamic treatment, number of freeway lanes, truck speed limit, and level of congestion was considered. The calculation of PCEs for multiple truck weight to power ratio populations was not found to be different from single truck weight to power ratio populations. The PCE values were tabulated in a compatible format to that used in the Highway Capacity Manual 2000. / Master of Science

The net present replacement value of all publicly and privately owned potable water pipes in the U.S. is on the order of $2.4 trillion dollars, and costs associated with deteriorating iron pipes is billions of dollars per year. Problems arising from iron corrosion include reduced lifetime of the material, scale buildup and energy loss, nonuniform corrosion and leaks, catastrophic failure, "red water," disinfectant loss and bacterial re-growth. Iron corrosion is a very complicated process and is affected by many factors. This research focused on the effect of disinfectant type, sulfate/chloride ratios, nitrate concentration, and magnesium hardness on iron corrosion. For the waters tested, chlorine better controlled red water and microbial activity in the bulk solution than chloramine. Changes in the sulfate/chloride ratio did not have a large effect on iron corrosion. High levels of nitrate increased the rate of chlorine decay as a result of free ammonia formation, and also increased the release of iron. Increased magnesium and zinc decreased the red water caused by high silicate. Microbiological activity is important in iron corrosion, and control of re-growth in water distribution systems is a major challenge for water utilities. A separate study examined the inter-relationship between iron corrosion and bacterial re-growth, with a special focus on the potential of iron pipe to serve as a source of phosphorus. Under some circumstances corroding iron and steel may serve as a source for all macronutrients necessary for bacterial re-growth including fixed carbon, fixed nitrogen and phosphorus. Conceptual models and experimental data illustrate that levels of phosphorus released from corroding iron are significant relative to that necessary to sustain high levels of biofilm bacteria. Consequently, it may be more difficult to limit re-growth on iron surfaces by limiting phosphorus in the bulk water. / Master of Science

Yes / In this paper, single-element and MIMO microstrip antenna with two pairs of unequal slits is proposed as a circularly polarized antenna with negligible back radiation for 5G mid-band handsets. The unequal pairs of slits are engraved on the antenna patch to guarantee the presence of the circular polarization (CP). The proximity-coupled feeding technique is used to excite the proposed microstrip antenna in order to provide larger antenna -10 dB bandwidth which approaches 10.8% (3.48-3.87 GHz). A novel analysis technique is proposed in this paper that demonstrates the 3D axial ratio pattern in order to generate CP in the broadside direction without affecting the structure of the ground plane which ensures weak back radiation. The 3 dB axial ratio bandwidth (ARBW) is found to be equal to 4.1% extended along the range (3.58-3.73 GHz). To make the design more compatible with the 5G mid-band handsets, the 2 × 2 MIMO structure of the proposed antenna with reduced mutual coupling (less than -20 dB) is also presented in this work. The simulation and measured results are in good agreement, and both verify the CP characteristics and the weak back radiation of the proposed antenna. / This paper is partially funded by British Council “2019 UK-China-BRI Countries Partnership Initiative Programme” with project titled “Adapting to Industry 4.0 Oriented International Education and Research Collaboration”.

After termination, cover crop residue can suppress weeds by reducing sunlight, decreasing soil temperature, and providing a physical barrier. Experiments were implemented to monitor horseweed suppression from different cover crops as well as two fall-applied residual herbicide treatments. Results suggest that cover crops, other than forage radish in monoculture, can suppress horseweed more consistently than flumioxazin + paraquat or metribuzin + chlorimuron-ethyl. Cover crop biomass is positively correlated to weed suppression. Subsequent experiments were designed to determine the amount of weed suppression from different cover crop treatments and if carbon to nitrogen (C:N) ratios or lignin content are also correlated to weed suppression or cover crop residue thickness. Results indicate that cereal rye alone and mixtures containing cereal rye produced the most biomass and suppressed weeds more than hairy vetch, crimson clover, and forage radish alone. Analyses indicate that lignin, as well as biomass, is an important indicator of weed suppression. While cover crops provide many benefits, integrating cover crops into production can be difficult. Hairy vetch, a legume cover crop, can become a weed in subsequent seasons. Multiple experiments were implemented to determine germination phenology and viability of two hairy vetch cultivars, Groff and Purple Bounty, and to determine when viable seed are produced. Almost all germination occurred in the initial cover crop growing season for both cultivars. Both cultivars had <1% of viable seed at the termination of the experiment. These results indicate that seed dormancy is not the primary cause of weediness. / Master of Science in Life Sciences / Cover crops are grown in the time between cash crop production, such as corn or soybeans. These crops are not grown for profit but mainly for environmental benefits such as reducing erosion and increasing soil organic matter and water infiltration. Another benefit of cover crops is the ability to suppress weeds. Cover crops can suppress weeds while they are actively growing by competing for resources such as light, water, and nutrients. After the cover crops have been terminated, or killed prior to cash crop planting, the residue can form a mulch layer on the soil surface which acts to suppress weeds by reducing the amount of sunlight that reaches the soil surface, decreasing soil temperature, and providing a physical barrier to slow weed growth. Horseweed is a problematic weed for growers to control and the number of herbicide options that growers can utilize is decreasing due to herbicide resistance. This weed has small seed and multiple germination periods, which cover crops have the ability to target. Experiments were designed to compare horseweed suppression from different cover crop monocultures and mixtures with suppression obtained from two fall-applied residual herbicide programs. The cover crop species used were cereal rye, crimson clover, hairy vetch, and forage radish. The cover crops were planted and herbicides applied in the fall. Data collected included horseweed counts, visible suppression ratings, and horseweed biomass taken in the following corn or soybean growing season. All cover crop treatments suppressed horseweed as compared to the nontreated check, with the exception of forage radish alone. The fall-applied herbicides did not perform as well as the cover crops. Results indicate that integration of cover crops is a viable tactic for horseweed management. As cover crop biomass increases the level of weed suppression also increases. Experiments were implemented to measure the level of weed suppression and to determine if the composition of the cover crop residue is important in weed suppression. Monocultures and mixtures of the same four cover crop species listed above were grown prior to corn and soybean production. At cover crop termination, samples were taken to determine biomass, carbon to nitrogen (C:N) ratio, and lignin content. Cereal rye and mixtures containing cereal rye provided > 55% weed suppression 6 weeks after cover crop termination. Analyses also indicated that lignin, as well as biomass, is an important predictor of weed suppression after termination. While cover crops have many benefits, there can be some complications. Hairy vetch is a legume cover crop species that has the ability to suppress weeds but can also become weedy in subsequent crops. Experiments were performed to track germination and seed viability of two hairy vetch cultivars, Groff and Purple Bounty as well as determine when seeds are added to the soil seedbank. Over the course of the experiment, Groff had greater germination than Purple Bounty by 30% in the initial germination periods. Both cultivars had <1% of seed still viable at the end of the experiment. Also, both cultivars produce viable seed in mid-June. The results from these experiments indicate that seed dormancy is not the primary cause of weediness in hairy vetch and that if proper termination occurs prior to mid-June, seeds will not be added to the soil seedbank.

The main objective of this study is to analyze the effects cotton quality has on hedging and basis movements within the cotton market to help market participants minimize price risk. The effectiveness of using cotton futures in hedging price risk will be determined by calculating optimal hedge ratios by tenderable quality. Hedge ratios will be calculated using simple differences and error correction models (ECM) on overlapping price data, estimated under both generalized least squares (GLS) and maximum likelihood estimation (MLE). An empirical analysis shows that as cotton quality improves, the optimal hedge ratio decreases. ECMs estimated under GLS are found to be most efficient. It is also found that cotton classing data by quality has no significant effect on cotton basis. Farmers and merchandisers can take these results as a framework to better manage price and basis risk in the hedge and speculative scenarios.

Digital light Projection based Additive Manufacturing (AM) enables fabrication of complex three-dimensional (3D) geometries for applications ranging from rapid prototyping jet parts to scaffolds for cell cultures. Despite the ability in producing complex, three-dimensional architectures, the state of art DLP AM systems is limited to a single homogenous photo-polymer and it requires a large volume of resin bath to begin with. Extensible Multi-material Stereolithography (EMSL) is a novel high-resolution projection stereolithography system capable of manufacturing hybrid 3D objects. This system provides new capabilities, allowing more flexible design criteria through the incorporation of multiple feedstock materials throughout the structure. With EMSL manufacturing ability, multi-material programmable negative Poissons ratio honeycomb reentrant structures are realized. Researchers have been studying auxetic structures over decades, the mechanical property control of auxetic structure mainly relies on geometry design in previous studies. Now with the help of EMSL system, other design variables associated with auxetic structures, such as material properties of local structural members, are added into design process. The additional variables are then proved to have significant effects on the material properties of the auxetic structures. The ability to accurately manufacture multi-material digital design will not only allow for novel mechanical and material researches in laboratory, but also extend the additive manufacturing technology to numerous future applications with characteristics such as multiple electrical, electromechanical and biological properties. The design and optimization of EMSL system realizes novel structures have not been producible, therefore it will stimulate new possibilities for future additive manufacturing development. / Master of Science / Since 1970s, stereolithography, one of the most commonly known additive manufacturing techniques nowadays, has been improving the ability we make things. Through the controllable and repeatable photo-polymerization process, stereolithography can manufacture three-dimensional (3D) physical objects with fast speed, high accuracy and highly detailed surface finish. Today, stereolithography is already widely used in various rapid prototyping and manufacturing areas including dental products, jewelry prototypes, structural and tooling components. While latest researches continuously push its resolution to smaller scale or wider areas, this process is still limited to single material manufacturing. To go beyond this manufacturing limitation, this thesis reports an Extensible Multimaterial Stereolithography (EMSL) system. This system takes advantages of the sequential projections from a digital light modulator, combined with several lowcost while efficient mechatronics components to enable printing at least two types of materials with distinct colors or mechanical properties. With the multi-material printing capability from EMSL, novel multi-material 3D auxetic structures, which have only been theoretical concepts, are successfully manufactured and tested. The reliability of EMSL process and properties of the new materials are investigated with experiments and numerical calculations. The system can be further extended to print multiple feedstock materials into one complex architectural assembly. By realizing multi-material manufacturing capability, EMSL has broaden the potential applications of additive manufacturing and it will enable the development of multiple research and application areas including metamaterial, micro-electromechanical systems and bio-medical implants.

Yes / The content validity ratio originally proposed by Lawshe is widely used to quantify content validity and yet methods used to calculate the original critical values were never reported. Methods for original calculation of critical values are suggested along with tables of exact binomial probabilities.

The Florida District Courts of Appeal have undergone many changes over the last three years, including the adoption of video conferencing due to the Covid-19 pandemic, and the creation of a brand-new district for the first time since 1979. Included in this series of changes was a new rule that moves most of the circuit court’s appellate jurisdiction into the jurisdiction the District Courts of Appeals (DCAs). This change has added to the systemic pressures of the Florida DCAs. While the creation of a new district is a step in the right direction to protect the effectiveness and perception of the state’s intermediate appellate courts, more needs to be done. Unfortunately getting data from the courts is difficult; thus, there is little way for the public to sense their effectiveness. While the integration of technology has been positive, the current resources available to the courts to dispose of its cases are in need of expansion. Finally, there is a general need for more support for judges and their staff. Overall, the way that Appellate Courts operate has significantly changed, and the stress they are under has in turn increased because of these reasons; the creation of a new district—while expensive— was an important step to preserving the integrity of the courts.

Osteoporosis is a disease of the bones. It is often called the “silent disease," because someone could have it now or be at-risk without even realizing it. As a result, bones become weak and can break from a minor fall or, in serious cases, even from simple actions, like sneezing or bumping into furniture. Breaking a bone is often the first clue that someone suffers from osteoporosis. The diagnosis of osteoporosis can be made using conventional radiography and by measuring the Bone Mineral Density (BMD). The most popular method of measuring BMD is Dual-Energy X-ray Absorptiometry (DXA). In conventional methods the measurement of bone does not give information about the bone quality but for the bone quantity. A non-invasive method that will have the ability to determine the bone quality is of interest. Such a method will contribute to the prediction or even the prevention of bone malfunction. In this study, two quality parameters, that are designed to contribute to improved diagnostic methods of osteoporosis, are determined. Those bone quality parameters are the Calcium/Phosphate (Ca/P) and Hydroxyapatite/Collagen (HAp/Col) ratios. The algorithm developed allows us to trace the spectral changes which take place when an x-ray beam passes through filters based on the Lambert and Beer’s law. A large number of filters were applied to spectra so as to obtain pseudo-monoenergetic spectra. The optimum energy pair would derive from two quasi-monoenergetic spectra with sufficient number of photons which will result in the minimization of the Coefficient of Variation (CV) of the aforementioned ratios. Dual Energy x-ray method is used in order to obtain this energy pair. Both Single and Double exposure techniques are used. / Η οστεοπόρωση είναι μια ασθένεια των οστών. Συχνά αποκαλείται ως η «αθόρυβη ασθένεια», καθώς κάποιος δεν αντιλαμβάνεται ότι νοσεί από αυτή. Σαν αποτέλεσμα της ασθένειας αυτής, τα οστά αδυνατίζουν και μπορεί να σπάσουν ακόμα και με ένα πολύ μικρό πέσιμο, ή ακόμα στις πιο σοβαρές περιπτώσεις, ακόμα και με ένα φτέρνισμα ή ένα χτύπημα στα έπιπλα. Η θραύση ενός οστού είναι το πρώτο σύμπτωμα της εμφάνισης της οστεοπόρωσης. Η διάγνωση της οστεοπόρωσης μπορεί να γίνει με τη συμβατική ακτινογραφία και μετρώντας την πυκνότητα των οστικών αλάτων (BMD). Η πιο διαδεδομένη μέθοδος μέτρησης του BMD είναι η DXA. Στην παρούσα μελέτη, υπολογίστηκαν δύο ποιοτικοί παράμετροι , ο λόγος ασβεστίου-φωσφόρου (Ca/P) και ο λόγος υδροξυαπατίτη- κολλαγόνου (HAp/Col). Πραγματοποιήθηκε αλγόριθμος στον οποίο έγινε χρήση διαφόρων φίλτρων έτσι ώστε να τροποποιηθούν τα φάσματα ακτίνων-Χ και να αποκτηθούν σχεδόν μονοενεργειακά φάσματα. Επιπλέον χρησιμοποιήθηκαν οι τεχνικές μονής και η διπλής έκθεσης.