<p> Using soluble organic carbon in the form of dextrose as a growth limiting substrate, and pure cultures of Escherichia coli, the carbon-containing products of a completely mixed, environmentally controlled, continuous bioreactor were quantitatively analyzed in order to determine if accurate carbon balances are obtainable for a wide spectrum of bacterial growth rates, and if gaseous carbon production exhibits a correlation with bacterial growth rate. </p> <p> The techniques of experimentation and analysis were developed and refined during the course of the study. Errors were accumulated in the carbon balances, these being considered due to inaccuracies in sampling of the gaseous reactor effluent. Assessment of error significance was made statistically. Soluble and cellular carbon analyses were accurately completed. A limited correlation of gaseous carbon production rate with growth rate was demonstrated. </p> / Thesis / Master of Engineering (ME)

New Zealand is both an Annex I Party to the UNFCCC, and an Annex B country of the Kyoto Protocol. By ratifying the latter, NZ has committed to reduce greenhouse gas emission to 1990 levels. The country should take domestic actions and can also use any of the Kyoto Protocol flexible mechanisms. Afforestation and reforestation on low carbon density land has been recognised as a carbon sink and hence a possible mitigation option for climate change. The current situation for New Zealand is that at least over the first commitment period (2008-2012) the country is in deficit, because emissions have continued to grow over the 1990 level, there is an increase in the deforestation rate and lower rates of new planting. The objective of this study is to analyse the potential of the New Zealand forest sector as an integrated system to mitigate climate change. It also analyses the impact of different mechanisms on potential area of new land planting, management of stands, and the supply, allocation, and demand of wood, and wood products. The New Zealand forest industry carbon balance (i.e net atmospheric exchange minus emissions) is modelled for different national estate scenarios, log allocation of harvested volume and residues used for bioenergy. The net present value of these scenarios is estimated and the economic viability assessed. The level of incentives needed to increase the returns to an economically viable level is estimated in term of carbon unit value ($/tC). Moreover the land use economics at a project level (land market value vs land expectation value) is assessed. Incentives needed in monetary terms and carbon value are also estimated. The implications of discounting carbon benefits are discussed. It was found that the carbon balance of the whole industry should be analysed for policy development on climate change mitigation options. New planting, longer rotation ages, avoiding deforestation, and allocating additional harvested volume to sawmills showed positive impact to the atmosphere. New planting appeared to be not economically viable, thus incentives are needed. It is acknowledged that, there are emissions from the sector that were not included, and that data and models used need further research to improve the accuracy of the results. Moreover, assumptions on the economic issues and an analysis of simultaneous implementation of more than one mitigation option would also improve the results.

Boreal old-growth forests are key determinants in the global carbon cycle. It is unknown how the role of persistent old-growth forests will be in the carbon cycle in the face of predicted climatic changes. Eddy-covariance measurements are commonly used to quantify carbon exchange between ecosystems, such as forests, and the atmosphere. Error due to gap-fill method is of particular interest in these datasets. Here we filled a 15-year eddy covariance dataset from the Northern Old-Growth Boreal Black Spruce (Picea mariana) site located near Thompson, in central Manitoba, Canada using four different gap-fill methods. Our objectives were to determine if choice of gap-fill method affected annual NEP and if these errors compounded to even greater differences over the 15-year study period. Most significant differences in NEP among methods occurred from September to December, but variations during the growing season were responsible for most of the annual differences. / October 2016

Ferrochrome (FeCr) is a crude alloy containing chromium (Cr) and iron (Fe). FeCr is mainly used for the production of stainless steel, which is an important modern-day alloy. FeCr is produced from chromite ore through various smelting methods. In this study, the focus was on the pelletised chromite pre-reduction process, which is also referred to as the solid state reduction of chromite. In this process, fine chromite ore, a clay binder and a carbon reductant are dry milled, agglomerated (pelletised) and pre-reduced (solid state reduction) in a rotary kiln. The pre-reduced pellets are then charged hot, immediately after exiting the rotary kiln, into a closed submerged arc furnace (SAF). This production process option has the lowest specific energy consumption (SEC), i.e. MWh/ton FeCr produced, of all the FeCr production processes that are commercially applied. Other advantages associated with the application of the pelletised chromite pre-reduction process are that it eliminates the use of chromite fines, has a high Cr recovery, and produces low sulphur- (S) and silicon (Si)-containing FeCr. The main disadvantage of the pelletised chromite pre-reduction process is that it requires extensive metallurgical control due to the variances in the levels of pre-reduction achieved and carbon content of the pre-reduced pelletised furnace feed material. This implies that the metallurgical carbon balance has to be changed regularly to prevent the process from becoming carbon deficient (also referred to as ‘under coke’) or over carbon (also referred to as ‘over coke’). The analytical technique currently applied to determine the level of chromite pre-reduction is time consuming, making it difficult and expensive to deal with large numbers of samples. In an attempt to develop a technique that would be faster to determine the level of chromite pre-reduction, a new analytical method using a combination of scanning electron microscopy (SEM), image processing and computational techniques was investigated in this study. Metallurgical grade chromite (<1 mm), anthracite breeze (<1 mm), and fine FeCr (<1 mm) that were used to prepare pellets in the laboratory, as well as industrially produced pre-reduced pellets that had already been milled in preparation for the determination of the pre-reduction level with wet chemical analysis were received from a large South African FeCr producer. These laboratory prepared pellets and the industrially produced pellet mixtures were considered in this investigation. Samples were moulded in resin and polished in order to obtain SEM micrographs of the polished cross sections. Elements with higher molecular weights are indicated by lighter greyscale, while elements with lower molecular weights are indicated by darker greyscale in SEM micrographs. This basic principle was applied in the development of the new analytical technique to determine the level of chromite pre-reduction, with the hypothesis that the pixel count of white pixels (representing metallised particles), divided by the combined pixel count of white (representing metallised particles) and grey (representing chromite particles) pixels would be directly related to the level of chromite pre-reduction determined with the current wet chemical method. This hypothesis can be mathematically expressed as: The newly-developed analytical method was validated by correlating the white pixel% calculated with the chromite pre-reduction levels (%) determined with wet chemical analysis of laboratory prepared and industrially produced pellet mixtures, which had R2 values of 0.998 and 0.919, respectively. This suggests that the method can be used to determine chromite pre-reduction accurately. / MSc (Engineering Sciences in Chemical Engineering), North-West University, Potchefstroom Campus, 2015

Ferrochrome (FeCr) is a crude alloy containing chromium (Cr) and iron (Fe). FeCr is mainly used for the production of stainless steel, which is an important modern-day alloy. FeCr is produced from chromite ore through various smelting methods. In this study, the focus was on the pelletised chromite pre-reduction process, which is also referred to as the solid state reduction of chromite. In this process, fine chromite ore, a clay binder and a carbon reductant are dry milled, agglomerated (pelletised) and pre-reduced (solid state reduction) in a rotary kiln. The pre-reduced pellets are then charged hot, immediately after exiting the rotary kiln, into a closed submerged arc furnace (SAF). This production process option has the lowest specific energy consumption (SEC), i.e. MWh/ton FeCr produced, of all the FeCr production processes that are commercially applied. Other advantages associated with the application of the pelletised chromite pre-reduction process are that it eliminates the use of chromite fines, has a high Cr recovery, and produces low sulphur- (S) and silicon (Si)-containing FeCr. The main disadvantage of the pelletised chromite pre-reduction process is that it requires extensive metallurgical control due to the variances in the levels of pre-reduction achieved and carbon content of the pre-reduced pelletised furnace feed material. This implies that the metallurgical carbon balance has to be changed regularly to prevent the process from becoming carbon deficient (also referred to as ‘under coke’) or over carbon (also referred to as ‘over coke’). The analytical technique currently applied to determine the level of chromite pre-reduction is time consuming, making it difficult and expensive to deal with large numbers of samples. In an attempt to develop a technique that would be faster to determine the level of chromite pre-reduction, a new analytical method using a combination of scanning electron microscopy (SEM), image processing and computational techniques was investigated in this study. Metallurgical grade chromite (<1 mm), anthracite breeze (<1 mm), and fine FeCr (<1 mm) that were used to prepare pellets in the laboratory, as well as industrially produced pre-reduced pellets that had already been milled in preparation for the determination of the pre-reduction level with wet chemical analysis were received from a large South African FeCr producer. These laboratory prepared pellets and the industrially produced pellet mixtures were considered in this investigation. Samples were moulded in resin and polished in order to obtain SEM micrographs of the polished cross sections. Elements with higher molecular weights are indicated by lighter greyscale, while elements with lower molecular weights are indicated by darker greyscale in SEM micrographs. This basic principle was applied in the development of the new analytical technique to determine the level of chromite pre-reduction, with the hypothesis that the pixel count of white pixels (representing metallised particles), divided by the combined pixel count of white (representing metallised particles) and grey (representing chromite particles) pixels would be directly related to the level of chromite pre-reduction determined with the current wet chemical method. This hypothesis can be mathematically expressed as: The newly-developed analytical method was validated by correlating the white pixel% calculated with the chromite pre-reduction levels (%) determined with wet chemical analysis of laboratory prepared and industrially produced pellet mixtures, which had R2 values of 0.998 and 0.919, respectively. This suggests that the method can be used to determine chromite pre-reduction accurately. / MSc (Engineering Sciences in Chemical Engineering), North-West University, Potchefstroom Campus, 2015

<p><em>How do additional data of the same and/or different type contribute to reducing model parameter and predictive uncertainties?</em> This was the question addressed with two models – the HBV hydrological water balance model and the ICBM soil carbon balance model – that were used to investigate the usefulness of the Generalized Likelihood Uncertainty Estimation (GLUE) method for calibrations and uncertainty analyses.  The GLUE method is based on threshold screening of Monte Carlo simulations using so-called informal likelihood measures and subjective acceptance criterion. This method is highly appropriate for model calibrations when errors are dominated by epistemic rather than stochastic uncertainties.  The informative value of data for model calibrations was investigated with numerous calibrations aimed at conditioning posterior parameter distributions and boundaries on model predictions.  The key results demonstrated examples of: 1) redundant information in daily time series of hydrological data; 2) diminishing returns in the value of continued time series data collections of the same type; 3) the potential value of additional data of a different type; 4) a means to effectively incorporate fuzzy information in model calibrations; and 5) the robustness of estimated parameter uncertainty for portability of a soil carbon model between and tropical climate zones.  The key to obtaining these insights lied in the methods of uncertainty analysis used to produce them.  A paradigm for selecting between formal and informal likelihood measures in uncertainty analysis is presented and discussed for future use within a context of climate related environmental modeling.</p>

A Amazônia armazena em sua floresta na ordem de 95 a 120 PgC de biomassa viva e mais 160 PgC no solo, que podem ser rapidamente liberados para a atmosfera por meio da queima de biomassa e, também, pela mudança do uso da terra. Este estudo foi desenvolvido com o objetivo de elucidar a contribuição da Bacia Amazônica nas emissões de carbono no ano de 2010. A quantificação do CO2 foi realizada por meio da coleta do ar atmosférico utilizando aviões de pequeno porte que descreveram um perfil vertical em quatro locais, estrategicamente posicionado na Bacia Amazônica, e utilizando sistemas semiautomáticos de coleta de ar em 17 ou 12 altitudes diferentes. O Fluxo de emissão/absorção foi calculado pelo método de integração de coluna, que consiste na determinação da concentração de CO2 no perfil vertical, subtraído da concentração de entrada no continente, levando-se em conta o tempo que a massa de ar despende entre a costa e o local de amostragem. Para a determinação da concentração de entrada, foram utilizadas as concentrações medidas pela NOAA nas Ilhas de Ascencion e Barbados e, como traçador de massas de ar, o SF6. Foi encontrado um caráter emissor da Amazônia em território brasileiro para o ano de 2010, em torno de 0,41 PgC, considerando a média ponderada das quatro regiões estudadas, sendo a queima de biomassa a principal responsável. Para a determinação da emissão proveniente da queima de biomassa foi utilizado o CO, como traçador, e a razão CO:CO2. Apesar de possuir um perfil emissor neste ano anormalmente seco, foi possível observar um caráter sumidor de carbono. / The Amazon forest contains on the order of 95-120 PgC in living biomass and additional 160 PgC in soils, which can be quickly released into the atmosphere through the biomass burning and also by the land use change. This study was developed with the aim to elucidate the contribution of the Amazon Basin in carbon emissions. The quantification of CO2 was performed by collecting atmospheric air using small airplanes that described a vertical profile at four locations strategically positioned in the Amazon and using semi-automatic sampling systems in 17 or 12 different heights. The emission / absorption flux was calculated by column integration method, which consists in determining the vertical profile concentration, subtracted from the background concentration, taking into account the time that the air mass spends between coast and sampling site. To determine the background concentration, were used the concentrations measured by NOAA at the Ascencion and Barbados islands and, as an air mass tracer, the SF6. Was found a emission behavior at the Amazon in Brazil for the year 2010, around 0.41 PgC considering the weighted average of the four regions studied, being the biomass burning mainly responsible. To determine the biomass burning emission, was used the CO as a tracer and, the CO:CO2 ratio. Despite having an emitter profile at this abnormally dry year, it was possible to observe it behavior of carbon sink.

Forests can be an important element of an overall strategy to limit the atmospheric concentration of carbon dioxide (CO2) that contributes to climate change. As an integral part of the global carbon cycle, forests remove CO2 from the atmosphere as they grow, and accumulate carbon in tree biomass. Using wood products made from sustainably managed forests can reduce net CO2 emission by substituting in place of fossil fuels and energy-intensive materials. In this thesis the mechanisms by which wood product substitution can affect energy and carbon balances are studied. These include: the energy needed to manufacture wood products compared with alternative materials; the avoidance of industrial process carbon emission from e.g. cement manufacture; the use of wood by-products as biofuel to replace fossil fuels; and the physical storage of carbon in forests and wood materials. A methodological framework is first developed by integrating knowledge from the fields of forestry, industry, construction, and energy. A life cycle perspective is employed encompassing the entire product chain from natural resource acquisition to material disposal or reuse. Analytical challenges that are addressed include the functional unit of comparison, the fossil reference system, land use issues of wood vs. non-wood materials, and the diverse phases of the product life cycle. The methodology is then applied to two multi-storey wood-framed buildings in Sweden and Finland, compared with two functionally equivalent buildings with reinforced concrete structural frames. The results show that less primary energy is needed to produce the wood-framed buildings than the concrete-frame buildings. CO2 emission is significantly lower for the wood-frame buildings, due to reductions in both fossil fuel use and cement calcination process emission. The most important single factor affecting the energy and carbon balances is the use of biomass by-products from the wood product chain as biofuel to replace fossil fuels. Over the life cycle of the wood-framed buildings, the energy of biomass residues from forest operations, wood processing, construction and demolition is greater than the energy inputs to produce the materials in the buildings. Realisation of this benefit is facilitated by integrating and optimising the biomass and energy flows within the forestry, industrial, construction, energy, and waste management sectors. Different forest management regimes are studied in an integrated carbon analysis to quantify the carbon flows and stocks associated with tree biomass, soils, and forest products. Intensified forest management that produces greater quantities of biomass leads to net CO2 emission benefits by augmenting the potential to substitute for fossil fuels and non-wood materials. The increased energy use and carbon emission required for the more intensive forest management, as well as the slight reduction in soil carbon accumulation due to greater removal of forest residues, are more than compensated for by the emission reduction due to product substitution. Carbon stock changes in forests and wood materials can be temporarily significant, but over the building life cycle and forest rotation period the stock change becomes insignificant. In the long term, the active and sustainable management of forests, including their use as a source for wood products and biofuels, allows the greatest potential for reducing net CO2 emission. Implementation issues related to the wider use of wood-based materials to reduce energy use and carbon emission are also explored. An analysis of the effects of energy and taxation costs on the economic competitiveness of materials shows that the cost of energy for material processing, as a percentage of the total cost of finished material, is lower for wood products than for other common non-wood building materials. Energy and carbon taxation affects the cost of wood products less than other materials. The economic benefit of using biomass residues to substitute for fossil fuels also increases as tax rates increase. In general, higher taxation of fossil fuels and carbon emission increases the economic competitiveness of wood construction. An analysis of added value in forest product industries shows that greater economic value is added in the production of structural building materials than in other uses of forest biomass. Co-production of multiple wood-based products increases the total value that is added to the biomass produced on an area of forest land. The results show that production of wood-based building material is favoured economically by climate change mitigation policies, and creates high added value within forest product industries. / Skogsresurser kan utgöra en viktig del i en strategi för att begränsa koncentrationen av koldioxid (CO2) i atmosfären och därmed begränsa klimatförändringarna. Skog tar upp CO2 från atmosfären när den växer och kolet lagras i trädens biomassa. Trädprodukter från hållbart brukade skogar kan minska nettoutsläppen av CO2 genom att de kan ersätta fossilt bränsle och energiintensiva material. I denna avhandling studeras faktorer som påverkar energi- och kolbalanser när träprodukter ersätter alternativa produkter. Signifikanta faktorer är den energi som behövs för att framställa träprodukter jämfört med alternativa produkter, utsläpp av CO2 från industriella processer som vid cementproduktion, ersättning av fossilt bränsle med trärester samt lagring av kol i skog och träprodukter. En metodik har utvecklats för att studera dessa faktorer genom att integrera ämneskunskaper från byggkonstruktion, energi, industri och det skogliga området. Den bygger på ett livscykelperspektiv och innefattar hela material- och produktkedjor från naturresurs till avfall eller återanvändning av material eller produkter. De metodikfrågor som varit i fokus är den funktionella enheten för jämförelser, det fossila referenssystemet, utnyttjande av skogmark vid produktion av träprodukter samt produktens olika faser under en livscykel. Metodiken har sedan använts för att jämföra ett svenskt och ett finskt flervåningshus i trä med två funktionellt likvärdiga hus med betongstomme. Resultaten visade att det behövs mindre primärenergi för att tillverka trähuset än betonghuset. Energin som kan utvinnas från biprodukter under en träbyggnads livscykel – från skogsskötsel, förädling, konstruktion och rivning – är större än den energi som krävs för att tillverka byggnadsmaterialet i byggnaden. Nettoutsläppen av CO2 från både fossil primärenergi och cementkalcinering är också väsentligt lägre för trähuset, men användningen av biprodukter från skogsavverkning, träförädlingskedjan och rivningsvirke för att ersätta fossilt bränsle har störst påverkan på kolbalansen. För att fullt ut tillgodogöra sig biprodukters potentiella fördelar krävs att de olika sektorerna för skogsbruk, industri, konstruktion, energi och avfallshantering integreras och optimeras med avseende på energi- och materialflöden. Olika skogsskötselmetoder har analyserats för att kvantifiera de flöden och den lagring av kol som sker i biomassa, mark och träprodukter. Intensifierat skogsbruk gav mindre utsläpp av CO2 per ha skogsmark, eftersom potentialen ökade för att ersätta fossila bränslen och energiintensiva material. Denna substitutionseffekt kompenserade mer än väl för den ökning i energianvändning och de utsläpp av CO2 som den intensivare skogsskötseln medförde, inklusive för den minskning av lagrat kol i marken som uttaget av skogsrester medförde. Lagring av kol i skogar och träprodukter kan vara intressant i ett kort tidsperspektiv, men under en byggnads livscykel och ett skogsbestånds rotationsperiod har den liten betydelse. I längden uppnås den största minskningen av CO2-utsläpp genom en aktiv och hållbar skogsskötsel med uttag av skogsresurser för användning till träprodukter och energi. I denna avhandling studerades också hur användningen av träprodukter påverkas av energi- och miljöskatter. En analys av energi- och skattekostnadernas effekt på konkurrenskraften för trämaterial visade att energikostnaden är lägre för trämaterial än för andra vanliga byggmaterial. Energi- och koldioxidskatter påverkar träprodukter i mindre utsträckning än produkter i andra material. De ekonomiska fördelarna av att använda biomassa som ersättning för fossila bränslen ökar också med höjda skatter. Konkurrensfördelarna för träkonstruktioner ökar därför generellt i takt med högre skatt på fossila bränslen och CO2-utsläpp. En analys av förädlingsvärdet hos skogsprodukter visade på en större värdeökning vid produktion av byggnadsmaterial än för andra biomassebaserade produkter. Samproduktion av flera träprodukter ökade det totala värdet hos biomassan per skogsareal. Resultaten visade att produktion av träbaserade byggnadsmaterial får ekonomiska fördelar av klimatpolitiska åtgärder och att sådan produktion har ett högt förädlingsvärde för industrierna i träbranschen.

The boreal forest is one of the worlds largest forest biomes and comprises a major portion of the terrestrial carbon (C) sink. Quantifying the net C change in forest ecosystems is an important step in understanding and modeling the global C cycle. The goals of this project were: to estimate and compare the total change in ecosystem C over a 10-year period in two boreal forest stands using biometric and eddy-covariance approaches, and to evaluate the year-to-year changes in C uptake. This study utilized 10 years of eddy-covariance data and ecosys model data from the Old Aspen (OA) and Old Jack Pine (OJP) sites in central Saskatchewan, part of the Boreal Ecosystem Research and Monitoring Sites (BERMS). According to the eddy-covariance and C stock approaches, between 1994 and 2004 the net change in C storage at OA was 15.6 ± 4.0 and 18.2 ± 8.0 Mg C ha-1, respectively. At OJP, the 10-year net change in C storage from eddy-covariance was 5.8 ± 2.0 Mg C ha-1 in comparison to 6.9 ± 1.6 Mg C ha-1 from the carbon stock approach. While both sites were sinks of C between 1994 and 2004, the greatest increase in C occurred in different components - the forest floor at OA (14.6 Mg C ha-1) and in the living vegetation at OJP (8.0 Mg C ha-1). In 2004, total ecosystem C content was greater at OA (180.6 Mg C ha-1) than OJP (78.9 Mg C ha-1), with 50% (OA) and 39% (OJP) of the C in the detritus and mineral soil pools. During the 10-year period of eddy-covariance measurements, there was a positive correlation between both annual and growing season gross ecosystem photosynthesis (GEP) and live stem C biomass increment at OA, whereas no significant relationships were found at OJP. Stem C increment accounted for 30% of total net primary productivity (NPP) at both sites, and NPP/GEP ratios were 0.36 and 0.32 at OA and OJP, respectively. Overall, this study found good agreement between eddy-covariance and biometric estimates of ecosystem C change at OA and OJP between 1994 and 2004. Over that period at OA, eddy-covariance estimates of photosynthesis captured the inter-annual variability in C uptake based on the growth of tree rings.

The boreal forest is one of the worlds largest forest biomes and comprises a major portion of the terrestrial carbon (C) sink. Quantifying the net C change in forest ecosystems is an important step in understanding and modeling the global C cycle. The goals of this project were: to estimate and compare the total change in ecosystem C over a 10-year period in two boreal forest stands using biometric and eddy-covariance approaches, and to evaluate the year-to-year changes in C uptake. This study utilized 10 years of eddy-covariance data and ecosys model data from the Old Aspen (OA) and Old Jack Pine (OJP) sites in central Saskatchewan, part of the Boreal Ecosystem Research and Monitoring Sites (BERMS). According to the eddy-covariance and C stock approaches, between 1994 and 2004 the net change in C storage at OA was 15.6 ± 4.0 and 18.2 ± 8.0 Mg C ha-1, respectively. At OJP, the 10-year net change in C storage from eddy-covariance was 5.8 ± 2.0 Mg C ha-1 in comparison to 6.9 ± 1.6 Mg C ha-1 from the carbon stock approach. While both sites were sinks of C between 1994 and 2004, the greatest increase in C occurred in different components - the forest floor at OA (14.6 Mg C ha-1) and in the living vegetation at OJP (8.0 Mg C ha-1). In 2004, total ecosystem C content was greater at OA (180.6 Mg C ha-1) than OJP (78.9 Mg C ha-1), with 50% (OA) and 39% (OJP) of the C in the detritus and mineral soil pools. During the 10-year period of eddy-covariance measurements, there was a positive correlation between both annual and growing season gross ecosystem photosynthesis (GEP) and live stem C biomass increment at OA, whereas no significant relationships were found at OJP. Stem C increment accounted for 30% of total net primary productivity (NPP) at both sites, and NPP/GEP ratios were 0.36 and 0.32 at OA and OJP, respectively. Overall, this study found good agreement between eddy-covariance and biometric estimates of ecosystem C change at OA and OJP between 1994 and 2004. Over that period at OA, eddy-covariance estimates of photosynthesis captured the inter-annual variability in C uptake based on the growth of tree rings.