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Potatoes in the Eastern Shore of Virginia are traditionally planted between late February and early April and harvested between early June and late August. Potato prices are usually higher early into the harvest season and decrease slowly as the season progresses. Early planting dates are desirable for farmers, as it allows them to perceive higher prices for their product, but early planting is also associated with lower air temperature during the early season, which in turn can affect plant development, water and nutrient uptake, and overall yield. Additionally, variations in soil properties often affect nutrient and water availability for plants, as well as the distribution of soil-borne insect pests. Additionally, several techniques are available to map the variations of soil properties in commercial potato fields, but little effort has been made to relate this information to the potential presence of soil-borne pests. Hence, the objective of this project was to evaluate the effect of planting dates, nitrogen (N) rates, and irrigation regimes on potato production. Two comprehensive studies were conducted between February and July 2022 and 2023. The objective of the first study was to evaluate the effect of N rates, planting dates, and soil physicochemical properties in potato production and the presence of soil-borne pests. This study was established in a split-plot design with four replications, with planting dates on the main plot and N rates and time of application on the sub-plot. Late March planting resulted in the highest total tuber yield, while early planting produced significantly larger tubers. Early March planting reduced plant development and emergence, probably due to lower air and soil temperatures. There was no interaction between planting dates and N applications. Using N rates higher than 147 kg ha-1 resulted in no significant differences in total tuber yield. Regression analyses showed that the Normalized Differences Red Edge (NDRE) is an excellent predictor of N content in plant tissue and tuber yield. Moreover, Ca and H saturation percentages were linked to wireworm damage levels using classification algorithms. Similarly, K saturation percentage was identified as a potential predictor of nematode presence in this region. A second study was established with the objective of evaluating the effect of N rates and irrigation regimes on potato production. The study was established in a split-plot design with four replications, with the irrigation method on the main plot and total N rate on the subplot. Results from these experiments showed higher growth and tuber yield when combining overhead irrigation with crop evapotranspiration (ETc) estimation. Moreover, there were no significant differences when using N rates higher than 112 kg ha-1. Overall, results from these experiments suggest no changes in current N rate recommendations for this region. Additionally, these results suggest planting in late March and using irrigation regimes based on evapotranspiration with overhead irrigation systems. Future research should focus on adaptive fertilization based on growing degree days and refinement irrigation determination practices. / Master of Science in Life Sciences / In the Eastern Shore of Virginia, nearly 4,000 acres are annually dedicated to fresh white potato farming. The established planting window extends from early March to early April, aligned with peak market demands in late April. However, this traditional planting strategy exposes crops to varying temperatures, potentially affecting water and nutrient demands, as well as overall yield. A research project consisting of two studies was conducted with the objective of evaluating the effect of planting dates, nitrogen (N) rates, and irrigation regimes on potato production. The first study was conducted with the aim of optimizing yield and nutrient management by exploring the interplay between planting dates, N rates, and application timing. The second study evaluated overhead and subsurface drip irrigation systems with irrigation regimes determined either by crop evapotranspiration (ETc) or by soil moisture content through soil water sensors (SWS). Results demonstrated that early March planting resulted in delayed emergence and overall growth due to colder temperatures, while late March plantings produced the highest tuber yields. On the irrigation front, overhead irrigation integrated with ETc estimation consistently improved plant health and augmented yield. In addition, the Normalized Differences Red Edge (NDRE) index, obtained from multispectral drone imaging, produced a significant correlation with N content in plant tissue and with total tuber yields for both studies. This suggests its high potential as a yield prediction tool. Overall, results from these studies reinforce current N rate recommendations for Virginia. Furthermore, they not only refine regional potato cultivation practices but also suggest the need for research pivoting around adaptive fertilization based on growing degree days and the potential refinement of irrigation regimens.

Drone technology has changed the way people work in construction and civil engineering activities. The aim of this report is to investigate how drones can and should be used in the best possible way. Autodesk ReCap Photo and Agisoft Metashape Professional are the two photogrammetry software programs that have been compared. The results show that Metashape can create more accurate maps and 3D models, but requires more powerful hardware to operate and takes longer time to learn. ReCap Photo is easier to handle but produces maps and 3D models that are slightly less accurate. Interviews have been conducted with experts, and they highlight that the EU regulations governing drone activity pose a great challenge for optimal usage of drones in construction and civil engineering. Assuming that drones are operated in a safe manner, they unlock significant potential gains with respect to environment, work environment and economy. Some of the most important areas of application are volumetric measurements of gravel, inspections in high altitude environments and regular mapping of construction sites. / Drönartekniken har förändrat arbetssätten i bygg- och anläggningsverksamhet. Denna rapport syftar till att undersöka hur drönare kan och bör användas på bästa sätt. Autodesk ReCap Photo och Agisoft Metashape Professional är de två fotogrammetriprogramvaror som har jämförts. Resultaten visar att Metashape kan skapa mer noggranna kartor och 3D-modeller, men kräver kraftigare hårdvara och tar längre tid att lära sig. ReCap Photo är mer lätthanterligt men ger inte lika noggranna kartor och 3D-modeller. Intervjuer med sakkunniga har genomförts, och av dessa framgår att de EU-gemensamma lagarna som reglerar drönarflygning utgör en stor utmaning för att kunna använda drönarna optimalt i bygg- och anläggningsverksamhet. Förutsatt att drönare flygs på ett säkert sätt, banar de vägen för stora potentiella vinster med avseende på miljö, arbetsmiljö och ekonomi. Några av de viktigaste användningsområdena är volymberäkning av grushögar, inspektioner på hög höjd och löpande kartering av byggarbetsplatser.

Orientation Device is a tool for understanding the other towards recognizing alternative possibilities, for care and compassion, for expanding our culturally and politically bounded mindset, a tool of vital nausea and questioning compulsory heterosexuality. The work is a series of augmented reality (AR) experiences for mobile device that allow the audience to participate in documentary queer performances in any private or public setting. These immersive experiences challenge our perception of space. The LGBTQIA+ community is often disoriented within heteronormative spaces, and this work reverses that dichotomy by disorienting the audience. As a cisgender creator, I invite queer performers, artists, poets, and thinkers who express their identity in their creative practices. As the AR medium is widely distributable, I want to give the participants the potential opportunity to present themselves to a wide international audience through the poetics of augmented reality and documentary video holograms. / Master of Fine Arts / ORIENTATION DEVICE: poiesis of documentary volumetric video for augmented reality; location-aware interactive mise-en-scène; applied queer phenomenology; the potential of procedural worldmaking in the future

The need for water conservation continues to increase as global freshwater resources dwindle. In response, many golf course superintendents are implementing new methods and tools to become more frugal with their water applications. For example, scheduling irrigation using time-domain reflectometer (TDR) soil moisture sensors can decrease water usage. Still, TDR measurements are time-consuming and only cover small scales, leading to many locations being unsampled. Remotely sensed data such as the normalized difference vegetation index (NDVI) offer the potential of estimating moisture stress across larger scales; however, NDVI measurements are influenced by numerous stressors beyond moisture availability, thus limiting its reliability for irrigation decisions. An alternative vegetation index, the water band index (WBI), is primarily influenced by water absorption within a narrow spectral range of near-infrared light. Previous research has established strong relationships between moisture stress of creeping bentgrass (CBG) grown on sand-based root zones, a typical scenario for golf course putting greens. However, this relationship characterizes only a small portion of total acreage across golf courses, which limits widespread adoption. In our research, '007' CBG and 'Latitude 36'hybrid bermudagrass (HBG) were grown on three soil textures, USGA 90:10 sand (S), sand loam (SL) and clay (C), arranged in a 2 x 3 factorial design, randomized within six individual dry-down cycles serving as replications. Canopy reflectance and volumetric water content (VWC) data were collected hourly between 0700 and 1900 hr using a hyperspectral radiometer and an embedded soil moisture sensor, until complete turf necrosis. The WBI had the strongest relationship to VWC (r = 0.62) and visual estimations of wilt (r = -0.91) compared to the green-to-red ratio index (GRI) or NDVI. Parameters associated with non-linear regression were analyzed to compare grasses, soils, indices, and their interactions. The WBI and GRI compared favorably with each other and indicated significant moisture stress approximately 28 hr earlier than NDVI (P = 0.0010). WBI and GRI respectively predicted moisture stress 12 to 9 hr before visual estimation of 50% wilt, whereas NDVI provided 2 hr of prediction time (P = 0.0317). When considering the time to significant moisture stress, the HBG lasted 28 hr longer than CBG, while S lasted 42 hr longer than either SL and C (P ≤ 0.0011). Nonlinear regression analysis showed that WBI and GRI can be useful for predicting moisture stress of CBG and HBG grown on three diverse soils in a highly controlled environment. Our results provide substantial evidence and direction for future research investigating how WBI and GRI can expedite moisture stress assessment and prediction on a large-acreage basis. / Master of Science in Life Sciences / Managed turfgrasses provide several benefits including filtering pollutants, cooling their surroundings, generating oxygen, preventing erosion, serving as recreational surfaces, and increasing landscape aesthetics. Intensively managed turfgrass systems, such as on golf courses and sports fields, require more inputs to maintain acceptable conditions. Freshwater use is often excessive on intensively managed turfgrasses to maintain proper plant growth. Drought conditions often limit water availability, especially in regions with limited rainfall. Turf managers tend to over-apply water across large acreage when few localized areas begin to show symptoms of drought. Additionally, turf managers sometimes wrongly identify stressed areas from other factors as ones being moisture-deprived. Advancements such as the use of soil moisture meters have simplified irrigation decisions as an aid to visual inspections for drought stress. While this method enhances detection accuracy, it still provides no solution to increase efficiency. Expanding our current knowledge of turfgrass canopy light reflectance for rapid moisture stress identification can potentially save both time and water resources. The objective of this research was to enhance our ability to identify and predict moisture stress of creeping bentgrass (CBG) and hybrid bermudagrass (HBG) canopies integrated into varying soil textures (USGA 90:10 sand (S), sand loam (SL) and Clay (C)) using light reflectance measurements. Dry-down cycles were conducted under greenhouses conditions collecting soil moisture and light reflectance data every hour from 7 am to 7 pm after saturating and withholding water from established plugs. Moisture stress was most accurately estimated over time using two vegetation indices, the water band index (WBI) and green-to-red ratio index (GRI), with approximately ninety percent accuracy to visible wilt stress. The WBI and GRI predicted moisture stress of CBG in all soil types and HBG in SL and C approximately 14 hours before the grasses reached 50% wilt. While light reflectance varies on exposed soils, our research shows that underlying soils do not interfere with measurements across typical turfgrass stands. This research provides a foundation for future research implementing rapid, aerial measurements of moisture stressed turfgrasses on a broad application of CBG and HBG on constructed or native soils.

The urgent need to reduce green house gas emissions from the transport sector, particularly from heavy-duty trucks, has underscored the importance of developing more efficient internal combustion engines. Using computational fluid dynamics (CFD), this work investigated the impact of valve seat geometry on in-cylinder swirl, addressing a gap in research. Additionally, the suitability of steady-state simulations for providing valid qualitative data on port flow was assessed. To answer both research questions, two approaches were followed: steady-state port flow RANS simulations, and transient RANS simulations in a running engine setup. The results from the steady-state simulations highlighted the limitations of this approach to qualitatively predict swirl, as this quantity is highly dependent on the mesh. Despite these limitations, the steady-state simulations were still able to capture the trade-off between swirl and discharge coefficient, outlined in the literature. Transient simulations revealed that in-cylinder swirl is affected by the geometry of the valve seats. It was found that valve seats that direct the flow towards the liner, while avoiding strong flow separation tend to promote higher swirl, whereas valve seats that induce strong flow separation lead to lower swirl ratios. Despite the trade-off between swirl and volumetric efficiency, the volumetric efficiency losses were found to be practically negligible. The study emphasizes the need for a more comprehensive set of simulations, including more valve lifts and pressure ratios. Given the unsuitability of the steady-state simulations to predict swirl trends, future investigations should focus on replacing this approach by transient simulations with steady-state geometry and boundary conditions, properly addressing flow time-dependency at relatively low computational cost, and facilitating validation with experimental data.

A prototype 3-dimensional (3D) anode, based on multiwall carbon nanotubes (MWCNTs), for Li-ion batteries (LIBs), with potential use in Electric Vehicles (EVs) was investigated. The unique 3D design of the anode allowed much higher areal mass density of MWCNTs as active materials, resulting in more amount of Li+ ion intake, compared to that of a conventional 2D counterpart. Furthermore, 3D amorphous Si/MWCNTs hybrid structure offered enhancement in electrochemical response (specific capacity 549 mAhg-1). Also, an anode stack was fabricated to further increase the areal or volumetric mass density of MWCNTs. An areal mass density of the anode stack 34.9 mg/cm2 was attained, which is 1,342% higher than the value for a single layer 2.6 mg/cm2. Furthermore, the binder-assisted and hot-pressed anode stack yielded the average reversible, stable gravimetric and volumetric specific capacities of 213 mAhg-1 and 265 mAh/cm3, respectively (at 0.5C). Moreover, a large-scale patterned novel flexible 3D MWCNTs-graphene-polyethylene terephthalate (PET) anode structure was prepared. It generated a reversible specific capacity of 153 mAhg-1 at 0.17C and cycling stability of 130 mAhg-1 up to 50 cycles at 1.7C.

This thesis deals with simulation and rendering of fluid based volumetric effects, especially effect of fire and smoke. Computations are accelerated on graphics card using modern graphics API with motivation to achieve realistic visual results as well as physically correct calculations. Implemented volumetric effects are distributed as dynamic library which allows addition of these effects to existing applications.

Ce mémoire s'intéresse à la reconstruction d'un modèle 3D à partir de plusieurs images. Le modèle 3D est élaboré avec une représentation hiérarchique de voxels sous la forme d'un octree. Un cube englobant le modèle 3D est calculé à partir de la position des caméras. Ce cube contient les voxels et il définit la position de caméras virtuelles. Le modèle 3D est initialisé par une enveloppe convexe basée sur la couleur uniforme du fond des images. Cette enveloppe permet de creuser la périphérie du modèle 3D. Ensuite un coût pondéré est calculé pour évaluer la qualité de chaque voxel à faire partie de la surface de l'objet. Ce coût tient compte de la similarité des pixels provenant de chaque image associée à la caméra virtuelle. Finalement et pour chacune des caméras virtuelles, une surface est calculée basée sur le coût en utilisant la méthode de SGM. La méthode SGM tient compte du voisinage lors du calcul de profondeur et ce mémoire présente une variation de la méthode pour tenir compte des voxels précédemment exclus du modèle par l'étape d'initialisation ou de creusage par une autre surface. Par la suite, les surfaces calculées sont utilisées pour creuser et finaliser le modèle 3D. Ce mémoire présente une combinaison innovante d'étapes permettant de créer un modèle 3D basé sur un ensemble d'images existant ou encore sur une suite d'images capturées en série pouvant mener à la création d'un modèle 3D en temps réel. / This master concentrates on the reconstruction of a 3D model from multiple images. The 3D model is built with a hierarchical representation of voxels using an octree. A cube surrounding the object is calculated from the camera's positions. This cube contains all the voxels and it defines the position of the virtual cameras. The 3d model is initialized by a visual hull that is based on the uniform color of the images’ background. This visual hull is used to pre-carve the 3D model. Then a cost is calculated to evaluate the quality of each voxel as being on the surface of the object. This cost takes into account the similarity of the pixels from each images associated to a virtual camera. Finally a surface is calculated for each virtual camera using the SGM method that is based on the voxel cost. The SGM method takes the surrounding voxels into account when calculating the depth and this master presents a variation to this method where we take the previously excluded voxels into account. The excluded voxels coming from the initialization step or from the carving done by another virtual camera. The resulting surface is used to carve the voxel representation. This master presents an innovative combination of steps leading to the creation of a 3D model from a set of existing images or from a series of images capture one after another leading to a real-time creation of a 3D model.