The thesis solves the efficient production of the sheetmetal cover. The new technological procedure will save two manufacturing operations deep drawing. The deep drawing of the cylindrical vessel with a flange and its following calibration in accordance with the design documentation was choosed. The last stage of the deep drawing is the construcion of the circular cut-out and its bending. By doing so the final shape of the cover will be reached.

This paper addresses the minimum weight edge cover problem (MEC), which is stated as follows: Given a graph <i>G= (V,E)</i>, find a set of edges <i>S:S⊆E </i>and ∑_e∈S^w(e)</∑<sub>e∈Q^w(e)∀Q: Q is an edge cover. Where an edge cover <i>P</i> is a set of edges such that ∀v∈V <i>v</i> is incident to at least one edge in <i>P</i>. An efficient implementation of a 4/3-approximation for MEC is provided. Empirical results obtained experimentally from practical data sets are reported and compared against various other approximation algorithms for MEC.<br>

This research examined a single bulb-bearing edible plant species, yellow glacier lily (Erythronium grandiflorum ). Three main approaches to the research were taken: 1) an ecological study, to determine the general habitat requirements of the species in western Canada, and to investigate the nature of vegetative reproduction in the species; 2) an ethnobotanical study, consisting of an extensive literature search for all recorded First Nations' uses of the species (in Canada and elsewhere), in addition to interviews with contemporary Interior Salish elders; 3) a nutritional study, examining in detail the nutritional characteristics of the bulbs, and particularly changes in the carbohydrate content over the course of the growing season and with different types of treatments. The ecological data indicate that E. grandiflorum is more abundant in meadow environments or sites with deciduous cover than in sites with coniferous forest cover. Flowering plants tended to be more abundant and robust at low elevation meadows, while seedlings and juveniles were disproportionately represented at high elevation meadows. Decreased juvenile success in the low-elevation meadows may be related to relatively high litter from shrubs and grasses. Experimental data indicate that appendages on the bulbs, which persist as remnants of previous years' bulbs, can act as vegetative propagules if mechanically separated. In addition, both bulbs and appendages were successfully transplanted over a two-year period from a subalpine meadow to a very different habitat type, 1500 m lower in elevation. The ethnobotanical review confirms that the species was traditionally a highly significant root resource for northern plateau peoples, particularly the Secwepemc and Nlaka'pamux peoples, for probably thou.sands of years. These peoples collected, stored, and traded large quantities of the bulbs, and the traditional processing strategies generally included drying and pit-cooking. People developed a detailed ecological understanding of the species, and practiced active resource management strategies. Nutritional results indicated a carbohydrate-rich food resource, with the main storage carbohydrate consisting of starch (not inulin or other fructan) through most of the growing season. There are significant quantities of sugars (including fructo-oligosaccharides) present at the beginning of the growing season, but starch increases rapidly and peaks (along with overall food value) in the early (green) fruit stage of growth. For bulbs at the fruiting stage, drying markedly increases sugars in the bulbs relative to starch, while pit-cooking the dried bulbs does not have significant effects on relative amounts of carbohydrates. However, pit-cooking has important qualitative effects on the appearance, taste, and possibly storage properties of the bulbs, as well as representing an efficient processing strategy. I argue that traditional harvesting and management strategies practiced by First Nations people (including tilling, thinning, replanting of appendages, and landscape burning) mean that the ecology and ethnobotany of the species cannot be considered in isolation. Based on previous ecological and ethnoecological work on this and similar species, it seems likely that yellow glacier lily is adapted to a periodic, moderate disturbance regime, which traditional practices may have mimicked or enhanced. / Graduate

Urban areas are responsible for the majority of global anthropogenic CO2 emissions. Urbanization has altered the structure and function of terrestrial ecosystems and is increasing rapidly, further modifying global carbon cycling. The three research papers in this dissertation explore the role of urban vegetation in the carbon cycle using a combination of atmospheric observation, field measurements, remote sensing, and modeling. First, I characterized the spatiotemporal patterns of observed atmospheric CO2 mixing ratios and compared these data to estimated CO2 fluxes at three sites across Boston's urban-to-rural gradient. Total fossil fuel emissions estimates ranged from 1.5 to 37.3 Mg C ha-1 yr-1 between rural Harvard Forest and urban Boston. Despite large differences in emissions, atmospheric CO2 concentrations only differed by approximately 5%. The growing season length in Boston was approximately 31 days longer than in Harvard Forest, enhancing the period for biological carbon uptake. In Boston, gross primary production was 3.8 Mg C ha-1 yr-1, which was ~75% lower than gross primary production at Harvard Forest and ~10% of total anthropogenic carbon fluxes in Boston. Second, I assessed how forest-to-urban land cover change affected both aboveground biomass and productivity across eastern Massachusetts. I found that urban land covers contained less than half the biomass of adjacent forests, but the mean basal area increment of existing trees nearly doubled with development over time from 17.1 ± 3.0 to 35.8 ± 4.7 cm2 yr-1. Scaling this increase in growth suggests an aboveground biomass growth rate of 1.8 ± 0.4 Mg C ha-1 yr-1, a rate similar to that found in Harvard Forest, despite having only ~1/3 the standing aboveground biomass. Last, I assessed how above- and belowground ecosystem characteristics changed as a function of time since development and development intensity. I found that soil C and aboveground biomass showed significant differences with time since development. My data suggests that soil C, N, and bulk density are dependent on land use history, with previously agricultural sites consistently showing higher rates of soil N and C accumulation than previously forested and grassland sites. Taken as a whole, this dissertation highlights the potential consequences of altered ecological and environmental conditions on tree growth, the legacy effects of land use history, climate, and land management practices on below ground soil C and N, and the importance of vegetation in the C cycle in urban areas.

Orientador: Alexandre Dal Pai / Resumo: O presente trabalho sugere modelos de correção para a irradiância solar difusa medida com o disco de sombreamento. A irradiância global foi medida por um piranômetro Eppley-PSP; a irradiância normal direta por um pireliômetro Eppley-NIP adaptado a um dispositivo de rastreamento solar ST-3 e irradiância difusa por um piranômetro Eppley-PSP instalado em um disco de sombreamento. O Laboratório de Radiometria Solar da Universidade Estadual Paulista forneceu as medições durante os anos de 1997 a 2000. Os resultados mostraram que ambos os modelos sugeridos, o modelo para todas as coberturas de céu e o modelo para as diferentes coberturas de céu melhoram a medida da irradiância difusa pelo método do disco de sombreamento permitindo a geração de um banco de dados de radiação global, direta e difusa, sem altos investimentos financeiros. A medida da Irradiância difusa sem correção apresentou um MBE de -4,64% e um RMSE de 12,23%, enquanto que os modelos de correção para todas as coberturas de céu e para as diferentes coberturas de céu obtiveram MBE de 0,48% e 0,85 e RMSE de 10,52% e 9,91%, respectivamente. / Doutor

<p><a>Indiana is the leading state of cover crop adoption within the Upper Mississippi River Basin. However, since 2015 the cover crop adoption has slowed to a plateau. In order to regain the previous momentum, there must be an increased understanding of the spatiotemporal dynamics of cover crop adoption on the county and watershed scale. Currently, the cover crop adoption is monitored biannually through a driving transect survey method that investigates only 8.5% of the watershed and extrapolates to the entire county. However, the observations made by the driving transect survey can merely cover limited fields and is time-consuming. In addition, the driving transect survey did not provide comparative analysis among consecutive years. Therefore, we developed a rapid cover crop survey method by using remote sensing technology. The fundamental objectives of this research are: (1) evaluating the accuracy of the rapid cover crop survey method relative to the driving transect data and determining the best cut-off value (COV) of Normalized Difference Vegetation Index (NDVI); (2) performing a hindcasting analysis of cover crop adoption within the Big Pine Creek Watersheds within the period of 2014-2018 by employing a rapid cover crop survey remote sensing techniques; (3) accessing cover crop adoption management tendencies of farmers within the Big Pine Watersheds, and (4) determining the cover crop adoption tenure of farmers within the Big Pine Creek watersheds between 2014 and 2018. The cover crop management tendency represents the farmers’ preference on cash crop rotation method after harvesting cover crops, and the cover crop adoption tenure means that how often farmers adopt cover crops in a specific field in the research period.</a></p> <p>The results of this research demonstrated that relative to the conventional driving transect, remote sensing is a feasible method to successfully detect cover crop adoption on a county and watershed scale. Over a 4-year period (2015-2018), Producer’s Accuracy (PA) under the best COV, which represented how much vegetation-covered field recorded in transect data that can be captured in the processed NDVI map, was 89.02%. This PA value was relatively high compared with previous spatial crop classification research. The rapid remote sensing method also provided individual field locations of cover crop adoption over time within the entire watershed, compared to the driving transect that only gives extrapolated average of adoption. The hindcasting analysis of cover crop adoption revealed a 74% increase in cover crop acreage in the watershed from 2014 to 2018, which equated to a 0.71% increase in land receiving cover crops among all cultivated land annually. The evaluation of farmer cover crop adoption tendencies demonstrated that over a 4-year period, cover crop adoption going into corn was 19.7% greater on average relative to before soybean. Another key finding was that the level of cover crop adoption annually in the watershed was heavily influenced by the cash crop rotation. The cover crop tenure analysis demonstrated that agricultural fields of greater cover crop tenure represented the smallest portion of the cultivated land in the watershed, where 84.2% of the watershed was void of cover crop adoption and field that received cover crops for more than 4 consecutive years represented only 1% of cultivated land.</p> <p> To conclude, we are confident that the rapid cover crop survey method could replace the traditional driving transect survey. Our findings suggest that rapid assessment methods of cover crop adoption involving processed NDVI map could help advance the effectiveness, speed, and accuracy of cover crop adoption and assessment in the state of Indiana and the entire Mississippi River Basin region.</p>

<p><a>In the United States and Canada, weed interference in corn (<i>Zea mays </i>L.) costs farmers nearly $4 billion per year. Weed control has been achieved primarily through herbicides and tillage. As no-till corn acres have increased, dependence on herbicides has also increased. Herbicide-resistant weed infestations have pressured many growers into other weed management practices, such as adding winter cover crops into crop rotations. Field experiments were conducted in 2017 through 2018 and 2018 through 2019 at three locations in Indiana to determine residual herbicide efficacy applied at cereal rye termination and after corn planting in cereal rye (<i>Secale cereale</i> L.) and winter-fallow no-till corn. Weed biomass and density suppression was dependent on weed species and was influenced by cereal rye biomass at termination. Weed biomass was suppressed by up to 84% by cereal rye alone. Weed biomass reduction by a residual herbicide premix was similar in both cereal rye and non-cover crop treatments in most site-years, however cereal rye and the residual herbicide premix together resulted in decreased giant ragweed (<i>Ambrosia trifida </i>L.) and summer annual grass biomass compared to the residual herbicide premix applied alone in one site year. Late-season grass weed density was reduced by residual herbicides, but was unaffected by cover crop treatment. Late-season common cocklebur density and biomass increased in cereal rye treatments compared to non-cover crop treatments. </a></p> <p>Other field experiments were conducted at the same locations in 2017 through 2018 and 2018 through 2019 to determine the effect of cover crop species, termination timing, and chemical cover crop termination strategies on weed control and corn yield. Crimson cover (<i>Trifolium incarnatum </i>L.), cereal rye, and a cereal rye/crimson clover mix were terminated two weeks before, at, and two weeks after corn planting. All plots were terminated using glyphosate and atrazine, however others were also terminated with dicamba and acetochlor. The addition of acetochlor generally reduced early-season weed biomass or density, but not in cereal rye and cover crop mix treatments that were terminated at or after corn planting. Late-season summer annual grass biomass was reduced when cover crop biomass at termination was over 8000 kg ha^-1. Late-season common cocklebur density in 2018 was 450% to 800% higher in cover crops containing cereal rye, compared to crimson clover treatments. Corn yield was reduced by 23% to 67% in cereal rye and cover crop mix treatments in two out of three site-years in 2018, however corn yield was not reduced by crimson clover in either year, nor by cereal rye or the cover crop mix in 2019.</p>

Continental scale analysis of the savanna biome indicated that fire did not spread at tree canopy cover above 40%. This study investigates this relationship in a field study. It is possible that the type of tree (forest vs. savanna) may influence the amount of shade experienced by the understory and therefore this study also explores differences in LAI between congeneric pairs of forest and savanna tree species. Data were collected in two major South African savanna parks. Plots were set out to measure grass biomass in reference to canopy cover in both Kruger National Park (n=60) and the Hluhluwe-iMfolozi Game Reserve (n=82). Seven congeneric pairs were selected to compare leaf area and LAI between forest and savanna tree species using a destructive method. Against expectations, it was only when canopy cover reached 80% that grass fuel load was too low to support fire spread in all Kruger National Park plots (Pr=O) and 89% of the Hluhluwe-iMfolozi Game Reserve plots (Pr=0.11). No consistent, general relationships were evident with leaf area or LAI in comparisons between forest-savanna congeneric pairs. The significance of these findings and future direction is discussed.

Image classification based on remotely sensed data is the primary domain of automatic mapping research. With the increasing of urban development, keeping geographic database updating is imminently needed. Automatic mapping of land cover types in urban area is one of the most challenging problems in remote sensing. Traditional database updating is time consuming and costly. It has usually been performed by manual observation and visual interpretation, In order to improve the efficiency as well as the accuracy, new technique in the data collection and extraction becomes increasingly necessary. This paper studied an object-based decision tree classification based on orthophoto and lidar data, both alone and integrated. Four land cover types i.e. Forest, Water, Openland as well as Building were successfully extracted. Promising results were obtained with the 89.2% accuracy of orthophoto based classification and 88.6% accuracy of lidar data based classification. Both lidar data and orthophoto showed enough capacity to classify general land cover types alone. Meanwhile, the combination of orthophoto and lidar data demonstrated a prominent classification results with 95.2% accuracy. The results of integrated data revealed a very high agreement. Comparing the process of using orthophoto or lidar data alone, it reduced the complexity of land cover type discrimination. In addition, another classification algorithm, support vector machines (SVM) classification was preformed. Comparing to the decision tree classification, it obtained the same accuracy level as decision tree classification in orthophoto dataset (89.2%) and integration dataset (97.3%). However, the SVM results of lidar dataset was not satisfactory. Its overall accuracy only reached 77.1%. In brief, object-based land cover classification demonstrated its effectiveness in land cover map generation. It could exploit spectral and spatial features from input data efficiently and classifying image with high accuracy.

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