Thesis (Ph. D.)--University of Michigan, 1938. / "Reprinted from the Journal of the American chemical society, 60 ... (1938)." Includes bibliographical references.

Thesis (M.A.)--University of Wisconsin--Madison, 1975. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

As amostras de carvão ativo de bagaço de cana-de-açúcar foram preparadas em temperaturas de carbonização de 500, 600 e 700 ºC, com tempos de ativação de 60 e 120 minutos e concentração de agente ativante (ZnC12) 30 e 60% em relação ao bagaço seco original. Foi utilizado como padrão, para verificação de eficiência, um carvão ativo alemão (Riedel). Estas amostras foram caracterizadas pelas seguintes análises: rendimento; teor e umidade; teor de cinzas; pH; teor de substâncias solúveis em água. Foi também estudado o desempenho destas amostras no descoramento de água de lavagem de cana-de-açúcar, utilizando 1% e 1,5% em peso de carvão ativo. Amostras preparadas a 500 ºC, 60 minutos e concentração de agente ativamente 0%, 30% e 60% em relação ao peso de bagaço seco original foram utilizadas no tratamento de água de lavagem de cana-de açúcar visando a diminuição do potencial poluidor, essas mesmas amostras foram utilizadas para determinação de poder de adsorção, equação e isoterma de Freundlich. Os resultados mostraram ser viável, em escala de laboratório a obtenção de carvão ativo de bagaço de cana-de-açúcar, para utilização no tratamento de água de lavagem de cana-de-açúcar visando diminuir o seu potencial poluidor. / Samples of activated carbon from cane-thrash were prepared in carbonization temperatures of 500, 600 and 700 ºC; activation times of 60 and 120 minutes, and concentrations of activating agent (ZnC12) 30 and 60% in relation to the original dry bagasse. A German activated carbon, was used a standard (Riedel). The samples were characterized by the following analysis: yield, proportion (5) of humidity, proportion of ashes; pH; proportion of solubles in water substances. It was also studied the performance in discolouring sugar-cane washing water using 1% and 1,5% in weight of activated carbon. Samples prepared in 500 ºC, 60 minutes and activating agent concentration of 0%, 30% and 60% in relation to the weight of the original dry bagasse were used in the treatment of sugar-cane washing water the purpose of reducing the polluter potential. They were used to determine the adsorption power, equation and Freundlish isotherm. The results showed it is possible to obtain active carbon from cane-thrash in laboratory scale, to be used in the treatment of sugar-cane washing water with the purpose of reducing its polluter potential.

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Charcoal rot of soybean is an important disease affecting soybean. Charcoal rot is caused by the ubiquitous soilborne fungus Macrophomina phaseolina (Tassi) Goid. The fungus infects over 500 plant species. Although charcoal rot occurs primarily under drought-like conditions, it has also been reported in high-yield irrigated soybean environments. Symptoms of charcoal rot on soybean include wilting, stunting, and premature death. Management options to reduce charcoal rot-associated losses are limited. The objective of this research was to reduce M. phaseolina colonization of soybean by supplementing with secondary nutrients, specifically calcium and magnesium; therefore, reducing the concentration of the associated toxin, and determine if isolates of M. phaseolina from non-soybean hosts are pathogenic on soybean and rotational hosts. Between 2014 and 2016, non-irrigated, M. phaseolina-inoculated field and field replicate greenhouse experiments evaluated applications of 1,120 kg/ha of Ca and Mg alone and in combination at pre-plant, at-plant, and pre-plant followed by at-plant compared with an inoculated and non-inoculated. Disease ratings were visually assessed from roots collected at R3, R5, R7, and R8. Colony forming units (CFU) were used to quantify fungal colonization in root tissue. Gas chromatography mass spectrometry was used to quantify the concentration of botryodiplodin, a toxin previously associated with charcoal rot from root tissue. An application of calcium applied pre-plant provided the greatest numerical reduction, 39.7%, in toxin concentration and also reduced disease severity by 1.0% and CFUs by 15.4% when compared to the inoculated control in a moderately resistant cultivar. Although numerical benefits were observed, these data do not support applications of Ca and Mg as a charcoal rot management option. Numerical differences were observed between rotational hosts and isolates in pathogenicity studies. The greatest numerical reduction of 34% in soybean dry plant weight was observed with the corn isolate when compared to the non-inoculated control. Macrophomina isolates from corn had up to an 8% greater colonization in soybean than corn or cotton plants. Although no significance was observed between isolates with regard to dry plant weight and colonization, colonization occurred regardless of treatment; suggesting crop rotation should not be a stand-alone charcoal rot management option.

Fire is a primary driver of environmental change that can originate from natural or human ignition. Macroscopic charcoal (>125 "m) deposited into lake sediment is a record of a local fire event, whereas microscopic charcoal indicates fire activity on a broad landscape scale. Patterns of charcoal deposition may shed light on both human activities and climate history over long-time scales. Whether lowland Caribbean forests have experienced natural fire regimes over the long-term is unknown. Laguna Limón is a little-studied, large, freshwater lake on the northeastern coast of the Dominican Republic. We extracted four overlapping sediment cores totaling 315 cm in depth, and conducted analysis of macroscopic charcoal (2-cm), microscopic charcoal (16-cm), and loss-on-ignition (1-cm) to examine the long-term fire and environmental history of the area. Loss-on-ignition data established that the lake has only recently become organic rich, and was likely open to the sea as a low energy bay until 1400 Cal. Yr BP. The lake existed briefly as a wetland before transitioning to the modern freshwater lake 1200 Cal. Yr BP. Macroscopic charcoal was most abundant in the freshwater section of the core while microscopic charcoal peaked near the bottom of the core, and aligns well with other regional microscopic charcoal records. Overall the charcoal record reflects a combination of climatic and anthropogenic related charcoal deposition suggesting that fire has played an active role in the environmental history Laguna Limón. / Master of Science

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Student Number : 0215337D - MSc research report - School of Animal, Plant and Environmental Science - Faculty of Science / The impact of charcoal production on populations of selected savanna tree species was investigated on clay soils in Catuane, southern Mozambique. The study focused on answering questions related to the contribution of charcoal production to the local economy, the way populations of selected species were changed by the activity and the way in which they recover. Acacia nigrescens, Acacia nilotica and Ziziphus mucronata were identified as being amongst the most utilised species for charcoal production due to their hard wood quality. The charcoal production is being done by individuals from outside the local community. They are able to generate relatively high revenues from their product, which they sell to external markets, notably Maputo. The local community do not share in the benefits of the production. Interviews with members of the local community, indicated that they would prefer the activity to be stopped or more rigourously controlled. A comparison was made between adjacent harvested and un-harvested areas to assess the effects of charcoal production on the tree populations. Population structure by stem circumference classes were broadly similar in all three study species being characterised by a high frequency in the smallest circumference class. All other classes had considerably lower frequencies. With regards density, Acacia nigrescens and Acacia nilotica showed significantly lower densities in the harvested area. Ziziphus mucronata showed no significant difference. The frequency of stump circumference classes of Acacia nigrescens and Acacia nilotica were normally distributed with the class 81-90 cm being the most common. Ziziphus mucronata data were skewed to the left, with most stumps in the class 52-60 cm. Stump heights were mostly in the region of 20 cm. Circumferences of stumps were similar across the study species, being in the region of 90 cm. Coppicing in stumps was relatively poorly developed, with the majority of stumps having no successful coppice shoots. Kilns had an average density of two kilns per hectare. There was an inverse relationship between species abundance and mean harvesting radius. The results of the study indicate that harvesting has had an effect on species abundance and population structures. With decreases in density and a shift in age distribution towards a predominance of juvenile trees. However, the results are not unequivocal, since the area is not pristine and may have been subjected to other activities before harvesting for charcoal. The charcoal producers appear to harvest all sizes of tree. Their production data, approximately 1300 kg of charcoal produced per hectare, indicate the potential for over utilisation of the woodland resource. Futhermore their practice of cutting at low height subjects the stumps to growth retarding elements such as herbivory and fire, possibly contributing towards relatively unsuccessful coppicing and exacerbating the sustainability issue. To address these issues, along with the socio-economics issues, appropriate structures need to be implemented by government, in consultation with communities.