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<p> Peatlands are an important component of the global carbon cycle, storing 23 g C m-2 yr-1 to comprise a global carbon pool of approximately 455 Pg. Peat drainage and harvesting results in removal of surface vegetation, thereby reducing gross photosynthesis to zero. Moreover, lowering the water table increases carbon oxidation. Consequently, peatland drainage and mining can reduce or eliminate the carbon sink function of the peatland. In the first part of this study, net ecosystem CO2 exchange was studied in a natural (NATURAL), two-year (YOUNG) and seven-year (OLD) post cutover peatland near Ste. Marguerite Marie, Quebec during the summer of 1998. Although the NATURAL site was a source of CO2 during the study season, CO2 emissions were 270 to 300% higher in the cutover sites (138, 363, and 399 g CO2-C m-2; NATURAL, YOUNG and OLD, respectively). Active restoration practices and natural re-vegetation of peatlands have the potential to return these ecosystems to net carbon sinks by increasing net ecosystem production (NEP) and therefore decreasing CO2 emissions to the atmosphere. Net ecosystem CO2 exchange in a natural (NATURAL) peatland and a partly restored peatland (REST) near Ste. Marguerite Marie, Quebec, was compared with a naturally re-vegetated peatland (RVEG) near Riviere-du-Loup, Quebec. Ecophysiological parameters indicate that the REST site was more than twice as productive as the natural LAWNS and three times as the RVEG site (GPmax=18.0, 8.3, and 6.5 g CO2 m-2 d-1, respectively). These results indicate that active restoration improves carbon sequestration over natural re-vegetation but that the net carbon sink function at both sites has not been restored. The presence of Sphagnum cover at the RVEG site resulted in a significant decrease in net ecosystem respiration (NER), indicating the potential for decreasing soil respiration at restored cutover sites through increasing the volumetric soil moisture content.</p> / Thesis / Master of Science (MSc)

Due to inadequate long-term and large-scale observation approach for observation of soil moisture across the globe, this study intends to unveil the importance of using simulated soil moisture fields from land surface models, forced with observed precipitation and near-surface meteorology in monitoring drought and formulating effective water management practices for continued production irrigation applications. This study shows that socio-economic and ecosystem effects can be determined by evaluating spatial-temporal changes in irrigation applications. Thus, it facilitates understanding of the importance of water management and how water, energy, and carbon flows protect our climate and environment. By using Soil Moisture Active Passive (SMAP) in monitoring soil moisture, the information obtained is critical in providing early drought warnings, particularly in those parts of the United States that experience flash agricultural droughts. Further, this study highlights that frequent and reliable soil moisture measurements from SMAP helped improve the predictive capability of weather and climate models.

An improved knowledge of wood material behavior in hot-pressing environments can provide the benefit of an increased understanding of material properties during the manufacture of wood-based composites as well as insight into the development of new processes and products which manipulate the viscoelastic nature of wood. Two specific areas where additional knowledge is needed are: the high temperature equilibrium moisture content (EMC) behavior and the moisture dependent softening behavior. EMC data was collected and desorption isotherms were generated for mature and juvenile wood of aspen, loblolly pine and yellow-poplar at 50 and 160°C. High temperature EMC behavior was found to be distinct from that at lower temperatures, and considerable differences between the isotherms for juvenile and mature wood were detected. Substantial thermal degradation was observed during desorption at 160 °C and found to be strongly influenced by relative humidity. The thermal softening behavior of wood was evaluated using dielectric thermal analysis (DETA) at moisture levels from 0 to 20 percent. Coincident in situ relaxations of hemicellulose and amorphous cellulose in the range of 20 to 200 °C were observed and found to exhibit the characteristics of a secondary (glass) transition. The moisture dependence of this transition was characterized, and differences in the observed Tg were detected between juvenile and mature wood. Time-temperature superposition was also shown to be applicable to the wood-water system. / Ph. D.

The forest constitutes a very important element of renewable natural resources and makes a significant contribution to the Swedish bioeconomy. Biofuels are Sweden’s largest source of energy; of all the energy we use, 32% comes from biofuels, and of this approximately 85% comes from the forest and the forestry sector. In spite of this, logging residues constitute only a small component, compared to for example byproducts from sawmills and pulpindustry, and there is considered to be great potential for increasing their use. In 2019 the Swedish Forestry Agency issued new recommendations for logging residue harvest and ash recycling. This was a further development of the 2008 recommendations, which formed the foundation for how forest fuel producers work today, and were based on several decades of research into, for example, the impact on forest productivity and technological development of machinery. This practice of logging residue harvest aims to yield a dry and defoliated fuel where the needles are left at the clear felled area. However, if we are to increase the use of green renewable energy from forestry, it is very important to understand how different procurement systems affect the handling and storability of fuels from a quality perspective. It is also of great importance to understand, from the forest owners’ perspective, how removal of additional products from forestry influences nutritional balance and long-term productivity. If harvesting of logging residues does not affect long-term productivity, it is up to small-scale private forest owners to decide if removal of logging residues will be performed on their land. This thesis addresses some of these issues regarding removal of logging residues from the point of tree harvest up to the point of delivery to the energy conversion industry when the fuel chips are measured. Regarding different methods of handling of logging residues, the traditional method – dry-stacking – was compared with the, fresh-stacking method. The logging residues investigated came from stands that mainly consisted of Norway spruce (Picea abies (L.) Karst). The loads investigated in Paper 3 also came from logging of spruce-dominated forests. Both methods aim to dry the logging residues to an acceptable moisture content for delivery to the energyconversion industry. For the later part in the supply chain, moisture content measurements of logging residues were compared during a winter and summer season. The results of the studies indicate that the two methods do not create results that differ from what is allowed by the Swedish Forestry Agency and that they are quite similar with respect to dry mass- and nutrient removal from the clearfelled area. The results also show that similar yields and distributions of material are obtained from the logging residues with different stacking methods; in addition, the final felling itself, combined with the work performed by the forwarder operator, has a greater impact on the result than the method chosen for residue stacking of the logging residues. For the individual clear-felled area and the individual forest owner the increased removal associated with freshstacked logging residue has no major impact, however from a national perspective this small increase in removed logging residues may yield a supplement of between 0.5 – 1 TWh of green energy annually. Regardless of treatment, the studies indicated that the delivered fuel chips will have similar characteristics. The moisture content measurement techniques currently in use are sufficiently accurate and reliable. However, if the forest owner is unlucky and an error in measurement occurs or comminution and delivery happens during an especially wet period they may suffer a significant financial loss; indeed, it is generally not under the individual forest owners’ control when the logging residues are comminuted and delivered.

<p>Abstract (in English)</p><p>The task for the diploma work was to develop methods for measuring of moisture content by the Karl Fischer method, in jam, jelly sweets, and fudge.</p><p>The start premises was a for the company whole new equipment, which should be started up. Then programs should be developed for different kind of samples.</p><p>In the task it was as well included to develop methods for dissolving the different kind of samples, since the Karl Fischer method demands completely dissolved sample material.</p>

A madeira quando seca é um excelente isolante elétrico, porém quando a umidade da madeira aumenta, essa característica diminui fazendo com que esta passe a conduzir a corrente elétrica. A determinação do teor de umidade permite um controle do custo de produção e qualidade da madeira, além de facilitar a utilização de tratamentos preservativos e pintura. O método de determinação do teor de umidade com o uso de estufa é o método mais exato, e por esta razão é utilizado como padrão para calibrar outras técnicas. Por outro lado, a verificação do teor de umidade por meio da estufa é muito demorado e danifica parte do componente a ser analisado. O objetivo deste trabalho é propor uma metodologia para calibrar medidores elétricos de umidade, utilizando espécies de dicotiledôneas nativas e coníferas de florestamento. Na experimentação realizada foi possível constatar que apesar da menor precisão na determinação de teores de umidade, o método que utiliza medidores de umidade do tipo resistência, permite com algumas correções, a obtenção de valores confiáveis para o controle de umidade de peças de madeira serrada. Para isso foram desenvolvidas expressões obtidas por meio de análise de regressão linear que possibilitam fazer as correções necessárias nas leituras realizadas com o medidor elétrico do tipo resistência. / Wood when dry is an excellent electric insulating material. However when the moisture content of wood increases, that feature decreases, which makes it conduct electric current. Determining the moisture content allows the control of the production cost and the quality of the timber, and also facilitates the use of preservative treatments and painting. The method for the determination of the moisture content using the kiln is the most exact method, and therefore it is used as standard to calibrate other techniques. On the other hand, the verification of the moisture content by means of the kiln takes toe much time and damages part of the component to be analyzed. The aim of this work is to propose a methodology to gauge electric moisture meters using species of tropical and forestation hardwood and softwood. The experiments made it possible to verify that, even having less accuracy in determining the moisture content, the method based on moisture electric meters allows, with some adjustments, a reliable data acquisition for the control of moisture content of sawed lumber. For this matter, equations were developed by means of linear regression analysis allowing the necessary corrections of the readings carried out with the electric measurer of the resistance type.

A aplicação de um piso de madeira maciça sobre um contrapiso de concreto dá origem a um sistema que une dois materiais com diferentes características higroscópicas, e no qual a movimentação da umidade é ainda um fenômeno pouco conhecido. Visando um melhor entendimento desse fenômeno, a presente pesquisa buscou avaliar diferentes equipamentos para medir o teor de umidade do concreto, desenvolver uma metodologia para quantificar a água evaporável presente no substrato mineral e, a partir desses resultados, sugerir o teor de umidade do substrato mais adequado à aplicação de um revestimento de madeira. Corpos de prova de concreto, preparados com traço 3:1:1 e relação água cimento em torno de 0,5, foram submetidos a secagem ao ar, sendo que a variação do teor de umidade do concreto ao longo do tempo foi acompanhada pela perda de massa e com a utilização de medidores elétricos de umidade do tipo resistência e de contato.. Com o auxílio da análise de regressão foi possível estabelecer equações de correção para as leituras de umidade dos aparelhos. Para a quantificação da água evaporável no concreto, foi desenvolvido um corpo de prova utilizando-se cilindros de MDF com 6,0 cm de comprimento e 4,8 cm de diâmetro, inseridos em tubo de PVC e com uma das extremidades vedada com filme plástico e silicone. O cilindro de MDF mostrou-se um indicador eficiente da presença de água evaporável no concreto, uma vez que as taxas de adsorção pelo MDF puderam ser diretamente correlacionadas às taxas de evaporação pelo concreto. O efeito do adesivo no sistema concreto-madeira foi avaliado através da variação do gradiente de umidade em madeira de Jatobá (Hymenaea sp). Tacos de Jatobá, com dimensões de 100 mm x 80 mm x 18 mm e nos quais foram colocados sensores a 4 mm e a 17 mm de profundidade, foram colados em corpos de prova de concreto utilizando-se adesivo a base de PVA com 60% de sólidos. Os resultados mostraram que a água contida no adesivo não foi totalmente adsorvida pelo taco e o gradiente de umidade no sentido da espessura apresentou relação com o teor de umidade à profundidade de 17 mm, confirmando a hipótese de que existe um fluxo de umidade na interface concreto-madeira. / The application of solid wood flooring over a concrete subfloor originates a system joining two materials with different hygroscopic characteristics, and in which the moisture movement still is a little known phenomena. Looking for the better understanding of moisture relationship in this system, the present research evaluated different equipments to measure concrete moisture content, to develop a methodology to quantify the vaporizable water present in the mineral substrate and, according to these results, to suggest the substrate moisture content more adequate to application of a wooden covering. Sample test of concrete, prepared with trace 3:1:1 and relation water/cement around 0.5, were submitted to air drying and the variation of the concrete moisture content during the process was registered by the mass loss and with the use of electric moisture meters of resistance and contact types. Through regression analysis it was possible to establish equations to correct moisture meters readings. To quantify the vaporizable water present in concrete, a sample test was developed using cylinders of MDF with 6.0 cm of length and 4.8 cm of diameter, inserted in a PVC tube and with one of the extremities closed with plastic film and silicone. The MDF cylinder was an efficient indicator to quantify vaporizable water in the concrete, considering that the moisture adsorption rate of MDF samples could be directly correlated to the concrete evaporation rate. The effect of adhesive in concrete-wood system was evaluated through the variation of moisture content gradient in Jatobá lumber (Hymenaea sp). Flooring samples of Jatobá, with dimensions of 100 mm x 80 mm x 18 mm and moisture sensors inserted at depths of 4 mm and 17 mm, were glued to concrete sample test using a PVA based adhesive with 60% of solids. Results showed that the water contained in the adhesive was not totally adsorbed by the flooring sample and the moisture gradient across sample thickness is correlated to moisture content at depth of 17 mm, what confirm the moisture flow between concrete and wood.

O estudo da erodibilidade ganha importância quando se tratam de solos localizados em regiões tropicais, caracterizadas por altas pluviosidades e evaporações que dificilmente permitem ao maciço atingir um estado de saturação em campo. A erodibilidade e as propriedades hidráulicas determinam as condições de infiltração e de escoamento superficial e podem acelerar as feições erosivas através das perdas de partículas. Neste trabalho, observou-se que o grau de saturação in situ estabelece um potencial de sucção matricial (Sm) capaz de orientar o fluxo, absorção e armazenamento da água nos poros do solo. Deste modo, foi possível correlacionar as propriedades de absorção de água com as sucções mátricas de três solos (arenoso, argiloso e areno-argiloso), com comportamento erosivo e não-erosivo, ensaiados a diferentes teores de umidade inicial. Após o controle da sucção e umidade, através da panela de pressão de Richards, os solos foram submetidos ao ensaio de erodibilidade proposto por Nogami & Villibor (1979). Os índices de absorção (Iabs), de perda de massa por imersão (P) e de erodibilidade (E) determinados neste ensaio, quando correlacionados com as curvas características dos solos, mostraram a influência da sucção matricial no início do processo erosivo. Verificou-se uma tendência de aumento da perda de massa por imersão, quanto menor era o teor de umidade inicial imposta (maior sucção). Provavelmente, quando do início do evento chuvoso, o solo tende a ser mais erodível quanto mais seco estiver. Além disso, as correlações obtidas mostraram-se coerentes com o comportamento dos solos em estudo, permitindo uma estimativa da sucção (Sm) de um solo a partir de grandezas facilmente mensuráveis como o Iabs, obtido em ensaio simples e de fácil execução. / The study of erodibility gains importance when dealing with soil located in tropical regions, characterized by high precipitation and evaporation that allow hardly the massive soil to reach a state of saturation in the field. The erodibility and hydraulic properties define the infiltration conditions and the superficial flow, and they can accelerate the erosive process due to the losses of particles. In this work, we observed that the degree of saturation in situ establishes the potencial for suction matrix (Sm) can guide the flow, absorption and storage of water in soil pores. Therefore, experimentally, it was possible to correlate the properties of water absorption with the matrix suctions of three soils, with different initial moisture contents and erosive and non-erosive behaviors. After controlling the suction and moisture through the pressure Richards pressure chamber the soils were subjected to the erodibility test proposed by Nogami & Villibor (1979). The indexes of absorption (Iabs), mass loss by immersion (P) and erodibility (E) determinated in this experiment, when correlated with the characteristic curves of soils, showed the influence of matrix suction at the beginning of the erosion process. There was a trend of increased weight loss by immersion, the lower was the initial moisture content imposed (greater suction). Furthermore, the correlations obtained were consistent with the behavior of soils under study, allowing to estimate of suction (Sm) of a soil from easily measurable values such as the Iabs.