Pressurised entrained-flow gasification (PEFG) of woody biomass has the potential to produce high purity syngas for the production of vital chemicals, e.g., biofuels. However, ash-related issues such as reactor blockages and refractory corrosion need to be addressed before this potential can be realised from a technical perspective. These undesirable consequences can be brought about by slag formation involving inorganic ash-forming elements and the chemical transformations that they undergo during fuel conversion. The objective of this study was to elucidate the ash transformations of the major ash-forming elements and the slag formation process. A pilot-scale PEFG reactor was used as the basis of the study, gasifying different woody biomass-based fuels including wood, bark, and a bark/peat mixture. Different ash fractions were collected and chemically analysed. Reactor slags had elemental distributions differing from that of the fuel ash, indicating the occurrence of fractionation of ash material during fuel conversion. Fly ash particles from a bark campaign were also heterogeneous with particles exhibiting differing compositions and physical properties; e.g., molten and crystalline formations. Si was consistently enriched in the reactor slags compared to other major ash-forming elements, while analyses of other ash fractions indicated that K was likely volatilised to a significant extent. In terms of slag behaviour, near-wall temperatures of approximately 1050-1200 °C inside the reactor were insufficient to form flowing ash slag for continuous extraction of ash material during firing the woody biomass fuels alone. However, fuel blending of a bark fuel with a silica-rich peat changed the chemical composition of the reactor slags and bulk slag flow behaviour was evident. Thermochemical equilibrium calculations supported the importance of Si in melt formation and in lowering solidus and liquidus temperatures of Ca-rich slag compositions that are typical from clean wood and bark. Viscosity estimations also showed the impact that solids have upon slag flow behaviour and corresponded qualitatively to the experimental observations. Corrosion of reactor refractory was observed. The mullite-based refractory of the reactor formed a slag with the fuel ash slag, which caused the former to flux away. Reactor blockages were also resultant because of the high viscosity of this slag near the outlet.  A preliminary study into the corrosion of different refractories was also carried out, based on firing a bark/peat mixture.  Alumina-rich refractories consisting of corundum, hibonite, mullite, and andalusite tended to form anorthite and exhibited varying degrees of degradation. Infiltration of slag was evident for all the samples and was a severe mode of degradation for some refractories. For fused-cast periclase and spinel-based refractories, slag infiltration was limited to voids and no extensive signs of refractory dissolution were found. This is also supported by a thermochemical equilibrium calculations mimicking slag infiltration that incorporated viscosity estimations. The findings from this thesis contribute towards the development of woody biomass PEFG by highlighting issues concerning ash fractionation, slag behaviours and ash\slash refractory interaction that should be investigated further.

Shrub expansion in herbaceous ecosystems is emerging as an important ecological response to global change, especially in mesic systems where increases in canopy biomass are greatest. Two consequences of woody encroachment are increases in belowground resources, such as carbon and nitrogen, and reductions in above-ground resources such as light, which affect diversity, community trajectory, and ecosystem function. My objective was to determine how expansion of the nitrogen-fixing shrub Morella cerifera affected the resource environment across a chronosequence of shrub expansion on a Virginia barrier island. I quantified changes in carbon (C) and nitrogen (N) cycling, canopy structure and understory light associated with M. cerifera expansion. Litterfall in shrub thickets exceeded litterfall for other woody communities in the same region, and due to high N concentration, resulted in a return of as much as 169 kg N ha-1 yr-1 to the soil, 70% of which was from symbiotic N fixation. Litter and soil C and N pools were 3-10 times higher in shrub thickets than in adjacent grasslands. Understory light in shrub thickets decreased to as low as 0.5% of above-canopy light. Sunflecks in shrub thickets were shorter, smaller and less intense than sunflecks in forest understories. However, relative to other shrub species such as Elaeagnus umbellata, M. cerifera was less efficient at intercepting light. Although M. cerifera had the highest leaf area index (LAI) of five shrub species studied, M. cerifera was relatively inefficient at light attenuation due to low levels of branching, steep leaf angles and a relatively shallow canopy. The shift from grassland to shrub thicket on barrier islands, and in other mesic systems, results in a significant change in canopy structure that alters understory resource availability and greatly alters ecosystem function and trajectory.

Master of Science / Department of Biology / John M. Briggs / Woody encroachment has altered the vegetative structure of grasslands worldwide and represents a potentially irreversible shift in grassland dynamics and biodiversity. Clonal woody species appear to be one of the greatest contributors to the shift from graminoid to woody dominance in the tallgrass prairie. Part of the high success rate of clonal species may be attributed to an ability to circumvent recruitment filters through the integration of environmental heterogeneity and acropetal translocation of resources from mother to daughter ramets. The clonal shrub Cornus drummondii persists in a tension zone of the graminoid-dominated tallgrass prairie, where the dominance structure is primarily maintained through the direct and indirect effects of fire. The competitive displacement of native herbaceous vegetation associated with the establishment and expansion of C. drummondii causes a major alteration in the fuel dynamics responsible for the propagation and sustainment of fire, potentially contributing to biofeedback mechanisms that facilitate shrub expansion. The goal of this research was to quantify fire behavior parameters (temperature, intensity, rate of spread, and heat flux) in relation to C. drummondii invasions and to test physiological integration as a mechanism driving encroachment, using manipulation experiments at the Konza Prairie Biological Station. We observed a significant decrease in fireline intensity associated with the encroachment of C. drummondii, which was amplified by the effects of stem density and shrub island area. This alteration in fire behavior also led to reduced heat flux at stems within shrub islands, reducing the likelihood of tissue necrosis and top-kill. With additional fuel, temperatures and fire intensities were higher, similar to open grasslands. In severing rhizomes, and effectively severing the integration of clonal ramets, we observed a higher risk of mortality of daughter ramets. These rhizome severed ramets were more water stressed, had lower photosynthetic rates, and lower woody and foliar biomass production. These results indicate that C. drummondii significantly alters fire behavior, releasing ramets from the fire trap of successive top-killing, while the integration of intraclonal ramets allows daughter ramets to survive mid-summer drought and increases the likelihood of successful establishment and further clonal reproduction.

I chose the topic for my diploma thesis " The Excursion for the Elementary School Pupils along the Riverside of the Vrchlice River Aiming at Woody Plants". I took that topic intentionally just for several reasons. I wanted to bring a scenic valley of the Vrchlice river to pupilsˇ attention, to make the identification of woody plants more attractive in the natural scientific excursion, and to consolidate pupils' relation to nature and neighbouring environment. The first theoretical part deals with the general description of this valley and at the same time with the characteristic of animals and plants. Selected sorts of woody plants are described in the most detailed way as they became initial ones for working out worksheets and for the natural scientific excursion. The next part of the diploma thesis concerns inquiry research the goal of which was to find out the interest of teachers from nearby basic schools in worksheets dealing with the woody plants issues of the river Vrchlice. Worksheets dealing with selected wooden plants were elaborated on the basis of the research assessment. Those worksheets were verifield in the follow-up excursion. The closing part evaluates whether all the set targets were accomplished. Keywords Woody plants, educational excursion, worksheets, plants, pupils

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / A presente tese tem como intuito investigar as relações entre as narrativas de Machado de Assis e de Woody Allen, autores de épocas e culturas bastante distintas. No entanto, através da análise do papel da ironia na obra de ambos tornou-se possível aproximar Memórias póstumas de Brás Cubas, romance de 1881 de Machado, e Stardust Memories, filme lançado em 1980 pelo diretor Woody Allen. A investigação divide-se em três etapas. No primeiro capítulo, analisa-se a aproximação entre os dois autores através de uma mesma visão sobre a ficção presente tanto na obra de Machado quanto na de Allen. Esta visão encontra-se fundamentada através de uma tradição literária burlesca que rompe com o primado realista na narrativa ficcional. No segundo capítulo, procura-se demonstrar como a perspectiva não realista escapa a uma regra moralizante na ficção, para valorizar uma postura ética, isto é, para se definir o ethos da narrativa. A ironia, assim, será a morada da ficção de ambos os autores, que problematizam o mundo incluindo nele a própria narrativa. E no terceiro e último capítulo, analisa-se a relação ficcional nas duas obras com a memória. A memória, elemento constituinte da identidade humana, revela-se uma linguagem própria e opressora aos narradores memorialistas, impondo-lhes a inexorabilidade do tempo. Dessa forma, suas ficções seriam uma luta incessante do homem contra o seu caminhar para a morte

African savannas have experienced considerable woody encroachment over the last century, presenting an increasing problem from both ecological and socioeconomic viewpoints. Despite decades of work by savanna ecologists, the reasons for woody encroachment remain unclear. A major barrier to understanding the causes is the difficulty of disentangling the effects of broader-scale environmental changes, such as climate change and associated increases in atmospheric CO2, from localised effects such as fire. In this thesis I examine the effects of sixty years of experimental burning on the characteristics of woody vegetation in two climatically distinct African savannas, a wet and a dry savanna, to examine how long-term burning interacts with other potential drivers of woody encroachment. I examine tree abundance, woody cover, tree structure, diversity and community composition under four different fire regimes: annual, biennial, triennial and fire exclusion. Differences between sites and plots subject to different burning regimes are compared along with changes in these differences through time. Additionally, variation in the densities of Acacia, Combretum, Terminalia and Dichrostachys species were examined to establish how dominant species, particularly those responsible for encroachment, are affected by fire. Overall, I found that the effects of fire depend on savanna type. Fire lowered tree abundance and woody cover much more in the wet savanna than in the dry savanna. However, the maximal height of trees was much more constrained by increased fire frequency in the dry savanna than in the wet savanna. Woody encroachment occurred across both savanna types during the sixty year time period, but was much more rapid at the wet savanna. Additionally, encroaching species of Dichrostachys cinerea and Terminalia sericea in the wet savanna were shown to be more difficult to manage using fire. Overall as fire regimes were kept constant over the last sixty years, yet woody encroachment occurred across all fire treatments, it is most likely that an external driver is responsible. Rainfall change in both areas was minimal over the duration of the study, thus increased atmospheric CO2 would appear to be the most likely cause of woody encroachment. However, the magnitude and characteristics of woody encroachment are strongly mediated by fire and rainfall. Wet savannas would appear to be much more vulnerable to woody encroachment and existing management strategies are likely to become increasingly ineffective at keeping woody cover below potential maximum levels. Overall this thesis demonstrates that the effects of fire on woody vegetation in savannas vary depending on regional differences in rainfall and that processes of woody encroachment differ depending on savanna type.

With its appeal predicated upon what civilized society rejects, there has always been something hidden in plain sight when it comes to the outlaw figure as cultural myth. Damian A. Carpenter traverses the unsettled outlaw territory that is simultaneously a part of and apart from settled American society by examining outlaw myth, performance, and perception over time. Since the late nineteenth century, the outlaw voice has been most prominent in folk performance, the result being a cultural persona invested in an outlaw tradition that conflates the historic, folkloric, and social in a cultural act. Focusing on the works and guises of Lead Belly, Woody Guthrie, and Bob Dylan, Carpenter goes beyond the outlaw figure’s heroic associations and expands on its historical (Jesse James, Billy the Kid), folk (John Henry, Stagolee), and social (tramps, hoboes) forms. He argues that all three performers represent a culturally disruptive force, whether it be the bad outlaw Lead Belly represented to an urban bourgeoisie audience, the good outlaw Guthrie shaped to reflect the social concerns of marginalized people, or the honest outlaw Dylan offered audiences who responded to him as a promoter of clear-sighted self-evaluation. As Carpenter shows, the outlaw and the law as located in society are interdependent in terms of definition. His study provides an in-depth look at the outlaw figure’s self-reflexive commentary and critique of both the performer and society that reflects the times in which they played their outlaw roles. / https://dc.etsu.edu/etsu_books/1158/thumbnail.jpg

In northeast Brazil grazing is a major use of much of the semiarid woodlands (caatinga). Animal production is limited by lack of dry season forage, primarily deciduous tree leaves. Management is constrained by the persistence of undesirable trees that sprout from the stump (coppice). This study evaluates the possibility of manipulating coppicing trees to improve caatinga management, particularly dry season forage production. The season of cutting can influence coppicing. Trees were cut early and late in the wet and dry seasons. After two years, trees of all species cut in the late wet season produced less biomass than those cut in other seasons. Production of most species was maximized by cutting in the dry season. Desirable species should be cut during the dry season to maximize production and less desirable ones in the late rainy season to reduce coppicing. Seasonal cutting does not cause mortality, nor can it cause any prolonged change in the leaf: stem ratio. Another study quantifies the response to defoliation of coppice growth by goat browsing or manual removal. The palatable browse species sabia and catingueira suffered no mortality while less palatable species experienced significant mortality. One year after defoliation, defoliated trees still produced less biomass than non-defoliated trees. Browsed stumps sprouted again during the dry season. Changes in the abscission phenology of coppice growth were observed. Coppice growth retained leaves from 2 to 12 weeks longer than intact trees of the same species. Regrowth on browsed stumps remained green for the duration of the S month dry season. Delaying abscission regulates the availability of dry season forage, and has implications for animal production that merit further investigation. Coppice growth can be manipulated to change the species composition of the regenerating stand, improve seasonal forage balance, and reduce site disturbance. Changing from even-aged to uneven-aged management might facilitate these changes. Prospects for improving wood production are better than animal production because of the limits imposed by mixed production systems, land tenure, and human population growth.

Lack of forage quantity and quality limit livestock production during the dry season in northeast Brazil. Coppice produced following cutting of tree species in this area has the potential to increase forage quantity and quality during the dry season, because trees that coppice retain green foliage throughout most of the dry season. However, the palatability of coppice is often low. From a theoretical standpoint, woody plants with inherently slow growth rate should be less palatable to herbivores than plants with inherently fast growth rates, because plants that grow slowly allocate more carbon to compounds such as tannins and resins that reduce palatability. I tested this hypothesis with four tree species (Mimosa caesalpiniaefolia, Croton sonderianus, Auxemma oncocalyx, and Caesalpinia bracteosa) growing on both fertile (non-calcic brown) and infertile (lithic) soils. Inherent plant growth rates were determined by growing young plants of all species on both soil types in a greenhouse. Plants were fertilized with NPK (150 or 300 kg/ha) and watered to field capacity. Urea ((NH2)2CO),diammonium phosphate ( NH4)2 Po4 and KCL were used as sources of fertilizer. On fertile soils, Mimosa had the highest inherent growth rate, followed by Auxemma, Croton, and Caesalpinia. In pen and field trials, Mimosa was preferred by goats, followed by Auxemma, Croton, and Caesalpinia. Results were similar on infertile soils, but Croton had a higher growth rate than Auxemma, and Croton was preferred to Auxemma by goats . Fertilization with 150 or 300 kg/ha of NPK increased palatability of coppice of all plant species to goats on both fertile (non-calcic brown) and infertile (lithic) soils. Fertilization affected the chemical and physical characteristics of the four plant species. Concentrations of tannins and lignins decreased as did leaf toughness, while nitrogen, phosphorus, and calcium increased. In vitro organic matter and neutral detergent fiber digestibilities did not change. The prediction that fertilized plants would be lower in carbon based compounds than the unfertilized plants was supported by the results of my study.

Climate change is expected to continue to cause large increases in temperature in Arctic and sub-Arctic ecosystems which has already resulted in changes to plant communities; for example, increased shrub biomass and range. It is important to understand how warmer temperatures could affect the plant community in a wetland system because this region provides crucial high-quality forage for migratory herbivores during the breeding season. One mechanism by which warming could cause change is directly, where warming influences the vital rates of a species; these effects may be either positive or negative. Warmer temperatures may also affect a species indirectly, by impacting neighboring plants which compete with, or facilitate that species. Altering interspecific interactions may affect the abundances of the surrounding species. Recent research shows these ‘indirect’ effects which are mediated by biotic interactions may be important enough to reverse ‘direct’ effects of climate change in some plant communities. Furthermore, herbivores have been shown to mediate the effects of warming, in some systems, even preventing shrub expansion. However, the abundance of herbivores may change because of climate change so it is important to understand the role of herbivores in mitigating climate change effects to inform management strategy. Therefore, we aimed to determine the importance of direct and indirect effects of warming on this plant community while considering changing herbivore pressures. We conducted a two-year field experiment in the coastal wetlands of western Alaska to investigate how warming and herbivory will impact the abundances of two common species, a sedge and a dwarf shrub. We used the results from the experiment to predict the equilibrium abundances of the two species under different climate and herbivory scenarios and determine the contribution of direct and indirect effects to predicted community change. The sedge, Carex ramenskii, remained dominant in under ambient conditions, but the dwarf shrub, Salix ovalifolia, became dominant in warmed treatments. Herbivory mediated some of the effects of warming; where grazing was present community composition did not change as much as where it was not grazed. Results suggest that in the absence of goose herbivory, a 2°C increase could cause a shift from sedge to woody plant dominance on the coast of western Alaska. However, if grazing pressure by geese continues at the present rate, it may help retain the current community composition, though herbivory pressure was not sufficient to entirely reverse the effect of warming. Finally, we found that direct effects were more important than indirect effects in causing changes to this plant community.