Estágio realizado na empresa CIN - Corporação Industrial do Norte, S.A. e orientado pela Eng.ª Catarina Carneiro / Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 2010

Doctor of Philosophy (PhD) / Early recognition of plant invaders is key to their successful management. Yet knowledge of the ecological impacts of species before they become widespread is poor. This thesis examines the ecology of invasive Pinus radiata, a species which is known to spread from introduced plantings in Australia but is currently a low profile invader. Pinus invasions are considered major ecological problems in New Zealand and South Africa where wildlings are beginning to dominate natural areas and suppress native vegetation. Invasion success elsewhere and the large softwood estate in Australia suggest that pines may begin to dominate native eucalypt forests bordering large commercial plantations. This research focused on three components of impact of P. radiata; extent, abundance and effect per individual. The borders of 29 P. radiata plantations in NSW were surveyed in order to quantify the current level of invasion and to identify factors facilitating pine spread. Of particular interest was the role of propagule pressure, vegetation type and fire in the invasion process. The area of land in NSW currently invaded by P. radiata was estimated at almost 4 500 ha, although this is likely to be an underestimate due to an inability to detect wildlings (self-sown pines) at long distances from the plantation. Twenty six of the 29 plantations produced wild pines, however most of the sites are in the very early stages of invasion. Noticeable wildling populations were recorded at nine sites indicating that P. radiata is capable of establishing within native vegetation. Pine spread was most severe in the world heritage listed Blue Mountains region where pine densities reached up to 2000 per hectare in areas adjacent to the plantation and isolated pines were recorded up to 4 km from the source. The presence of isolated pines within intact native vegetation suggests that disturbance is not required for pine establishment in forested environments. Furthermore, high pine emergence and survival rates in eucalypt woodland and evidence of self reproduction by wildlings suggest that in the absence of adequate control measures pines may become established invaders in the Australian landscape. While low levels of current invasion at many sites hindered the ability to examine the factors facilitating invasion some variables that appear to be driving pine success were identified. At the landscape scale plantation size and residence time were significant predictors of the level of invasion at a site. Areas of native vegetation vi adjacent to plantations less than 40 years experienced very low levels of invasion suggesting a lag period between plantation establishment and invasion. However, pines with diameters up to 60 cm were observed growing adjacent to plantations younger than 40 years implying that the first colonisers are capable of establishing soon after plantation trees become reproductive. Propagule pressure was also found to have a strong influence on invasion success on a smaller scale manifesting in a significant positive relationship between the age of a plantation compartment and the likelihood of invasion. A negative relationship between plantation size and level of invasion was a surprising result and was influenced by just two large sites that happened to be located in areas of high rainfall. All sites receiving more than 1300 mm annual rainfall experienced low levels of invasion suggesting that this is a limiting factor for pine spread in NSW. There were significant differences in the level of invasion between vegetation types implying that some communities are more susceptible to invasion. Patterns of spread confirmed ideas regarding the facilitative effect of disturbance in the invasion process and the resistance of wet sclerophyll forest to invasion in Australia. An absence of wildlings in cleared land and areas of remnant bushland was attributed to high levels of grazing pressure. Wind direction did not appear to influence the distribution of pines close to the plantation, but evidence of long distance wind dispersal of pines was provided by an investigation of pine spread from the air at one site where large pines were found growing 10 km downwind from a mature plantation. Fire was found to have both a positive and negative influence on the invasion process. High intensity wildfires are capable of destroying large pines with diameters exceeding 50 cm. However, fire can stimulate seed release from cones resulting in large post-fire recruitment pulses. Seedling densities of up to 3050 per hectare were recorded almost 3 years after wildfire, suggesting that follow up control prior to recruits reaching coning age, i.e. within 5 years, would be beneficial. Surveys of wildling pines exposed to low intensity hazard reduction burns suggest that the majority of pines greater than 3 m in height and with a diameter of more than 10 cm will survive the fire. Low intensity prescribed fires that are carried out after pines have reached this size will fail to control wildling populations. To examine the influence of P. radiata once it has established in the native community this study focused on two mechanisms of impact, the addition of pine litter and increased shade due to an increase in canopy cover. Collection of pine litterfall vii within an invaded eucalypt woodland over a 2 year period recorded rates of up to 1400 kg/ha/year in the most heavily invaded area with a pine basal area of 11.3m2/ha. More than 70 % of pine litter fell directly below the pine canopy suggesting that the most severe litter effects will be limited to these areas. Glasshouse and field experiments were conducted to examine the influence of this increased litter load on the emergence of P. radiata and two native species. Recruitment of native plant species was impeded by litter levels of 6000 kg/ha, the equivalent of approximately 4 years of pine litterfall. Both P. radiata and the two natives responded similarly to pine and eucalypt litter suggesting the two litter types are influencing the recruitment phase equally. However, where pines are added to the system, increased litterfall rates could potentially result in the doubling of the litter load and hence a greater barrier to seedling establishment. Pine invaded eucalypt woodlands are also subjected to three fold increases in canopy cover. Trends in reduced emergence of native species under a pine canopy suggest that the addition of pines to eucalypt forests is likely to have a negative influence on native recruitment and may result in a shift towards a shade tolerant community. However, reversal of trends in emergence below pine canopy between seasons implies that quantifying invasion impacts requires a consideration of temporal variation. Increased levels of disturbance, forest fragmentation and an increasing pine estate are likely to lead to the infestation of new areas. Furthermore the lag phase associated with pine spread means that even if no new plantations are established the number of invasion events will increase. This study has identified a number of risk factors that can be used to guide plantation establishment and the management of invasion events. Minimising disturbance at plantation borders and increasing the ‘no planting’ zone will help to reduce the impacts of pines. Where possible new plantations should be established upwind of cleared land or at least, wet sclerophyll forest. Frequent monitoring of the borders of plantations yet to source invasions, particularly those greater than 40 years of age, will help identify problem areas before control becomes difficult and costly. Maps of the 29 plantations marked with areas of pine infestation will help prioritise sites for control and provide base level knowledge for future monitoring of pine spread. Stringent legislation that binds plantation managers to control wildlings beyond their boundaries is critical for the effective management of pine invasions. With infinite numbers of invaders and limited funds to dedicate to their control, a method of triaging species for management is critical. This is particularly difficult viii when information is typically biased towards invaders that are already widespread. By focussing on the ecological impacts of invaders it becomes possible to rank species on the basis of the threat they pose to native communities. Ecological research is capable of providing the knowledge to quantify invasion impacts and must remain at the centre of policy decisions.

Rapid changes in the global economy forces Industry to continuously seek competitive advantages; the University on the other hand pursue additional funding. Both Industry and University are trying to keep up with the accelerating pace of change, therefore partnership become critical in achieving key objectives. Research collaborations become essential and offer direct benefits for University and company participants. The impact extends well beyond the direct partners. When potential partners have the resources and knowledge to accomplish individual goals, working with outside experts can improve the quality of the research and help to reduce costs. Industry-sponsored research allows the University to obtain financial support as well as Industry exposure for its educational and research missions. The Technology and Human Resources for Industry Programme (THRIP) aims to boost South African Industry by supporting research and technology development, and by enhancing the quality and quantity of appropriately skilled people. THRIP brings together the best of South Africa's researchers, academics and industry players in funding partnerships that enable participants to improve the quality of their products, services and people. In 13 years it has become a powerful formula for stimulating innovation in South Africa - innovation leads to competitiveness and competition leads to growth. There are many difficulties in managing projects across organisational boundaries; their cultures and their mission differ. The goal and the prime objective of the industries are to make a profit and build-value for shareholders. The universities‟ missions are to develop new knowledge and educate the next generation. Factors that may prevent research collaboration with Industry from being successfully accomplished are: • The practical difficulties of managing a collaboration, • Deleterious effects on faculty and students, • Impact on the mission, • Reputation and financing of the University. Industry needs to overcome the following hurdles in order to foster greater collaboration: • Respect the value of research collaboration, • Incorporate University research into product development, • Management barriers. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2013.

Rapid changes in the global economy forces Industry to continuously seek competitive advantages; the University on the other hand pursue additional funding. Both Industry and University are trying to keep up with the accelerating pace of change, therefore partnership become critical in achieving key objectives. Research collaborations become essential and offer direct benefits for University and company participants. The impact extends well beyond the direct partners. When potential partners have the resources and knowledge to accomplish individual goals, working with outside experts can improve the quality of the research and help to reduce costs. Industry-sponsored research allows the University to obtain financial support as well as Industry exposure for its educational and research missions. The Technology and Human Resources for Industry Programme (THRIP) aims to boost South African Industry by supporting research and technology development, and by enhancing the quality and quantity of appropriately skilled people. THRIP brings together the best of South Africa's researchers, academics and industry players in funding partnerships that enable participants to improve the quality of their products, services and people. In 13 years it has become a powerful formula for stimulating innovation in South Africa - innovation leads to competitiveness and competition leads to growth. There are many difficulties in managing projects across organisational boundaries; their cultures and their mission differ. The goal and the prime objective of the industries are to make a profit and build-value for shareholders. The universities‟ missions are to develop new knowledge and educate the next generation. Factors that may prevent research collaboration with Industry from being successfully accomplished are: • The practical difficulties of managing a collaboration, • Deleterious effects on faculty and students, • Impact on the mission, • Reputation and financing of the University. Industry needs to overcome the following hurdles in order to foster greater collaboration: • Respect the value of research collaboration, • Incorporate University research into product development, • Management barriers. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2013.

Doctor of Philosophy (PhD) / Early recognition of plant invaders is key to their successful management. Yet knowledge of the ecological impacts of species before they become widespread is poor. This thesis examines the ecology of invasive Pinus radiata, a species which is known to spread from introduced plantings in Australia but is currently a low profile invader. Pinus invasions are considered major ecological problems in New Zealand and South Africa where wildlings are beginning to dominate natural areas and suppress native vegetation. Invasion success elsewhere and the large softwood estate in Australia suggest that pines may begin to dominate native eucalypt forests bordering large commercial plantations. This research focused on three components of impact of P. radiata; extent, abundance and effect per individual. The borders of 29 P. radiata plantations in NSW were surveyed in order to quantify the current level of invasion and to identify factors facilitating pine spread. Of particular interest was the role of propagule pressure, vegetation type and fire in the invasion process. The area of land in NSW currently invaded by P. radiata was estimated at almost 4 500 ha, although this is likely to be an underestimate due to an inability to detect wildlings (self-sown pines) at long distances from the plantation. Twenty six of the 29 plantations produced wild pines, however most of the sites are in the very early stages of invasion. Noticeable wildling populations were recorded at nine sites indicating that P. radiata is capable of establishing within native vegetation. Pine spread was most severe in the world heritage listed Blue Mountains region where pine densities reached up to 2000 per hectare in areas adjacent to the plantation and isolated pines were recorded up to 4 km from the source. The presence of isolated pines within intact native vegetation suggests that disturbance is not required for pine establishment in forested environments. Furthermore, high pine emergence and survival rates in eucalypt woodland and evidence of self reproduction by wildlings suggest that in the absence of adequate control measures pines may become established invaders in the Australian landscape. While low levels of current invasion at many sites hindered the ability to examine the factors facilitating invasion some variables that appear to be driving pine success were identified. At the landscape scale plantation size and residence time were significant predictors of the level of invasion at a site. Areas of native vegetation vi adjacent to plantations less than 40 years experienced very low levels of invasion suggesting a lag period between plantation establishment and invasion. However, pines with diameters up to 60 cm were observed growing adjacent to plantations younger than 40 years implying that the first colonisers are capable of establishing soon after plantation trees become reproductive. Propagule pressure was also found to have a strong influence on invasion success on a smaller scale manifesting in a significant positive relationship between the age of a plantation compartment and the likelihood of invasion. A negative relationship between plantation size and level of invasion was a surprising result and was influenced by just two large sites that happened to be located in areas of high rainfall. All sites receiving more than 1300 mm annual rainfall experienced low levels of invasion suggesting that this is a limiting factor for pine spread in NSW. There were significant differences in the level of invasion between vegetation types implying that some communities are more susceptible to invasion. Patterns of spread confirmed ideas regarding the facilitative effect of disturbance in the invasion process and the resistance of wet sclerophyll forest to invasion in Australia. An absence of wildlings in cleared land and areas of remnant bushland was attributed to high levels of grazing pressure. Wind direction did not appear to influence the distribution of pines close to the plantation, but evidence of long distance wind dispersal of pines was provided by an investigation of pine spread from the air at one site where large pines were found growing 10 km downwind from a mature plantation. Fire was found to have both a positive and negative influence on the invasion process. High intensity wildfires are capable of destroying large pines with diameters exceeding 50 cm. However, fire can stimulate seed release from cones resulting in large post-fire recruitment pulses. Seedling densities of up to 3050 per hectare were recorded almost 3 years after wildfire, suggesting that follow up control prior to recruits reaching coning age, i.e. within 5 years, would be beneficial. Surveys of wildling pines exposed to low intensity hazard reduction burns suggest that the majority of pines greater than 3 m in height and with a diameter of more than 10 cm will survive the fire. Low intensity prescribed fires that are carried out after pines have reached this size will fail to control wildling populations. To examine the influence of P. radiata once it has established in the native community this study focused on two mechanisms of impact, the addition of pine litter and increased shade due to an increase in canopy cover. Collection of pine litterfall vii within an invaded eucalypt woodland over a 2 year period recorded rates of up to 1400 kg/ha/year in the most heavily invaded area with a pine basal area of 11.3m2/ha. More than 70 % of pine litter fell directly below the pine canopy suggesting that the most severe litter effects will be limited to these areas. Glasshouse and field experiments were conducted to examine the influence of this increased litter load on the emergence of P. radiata and two native species. Recruitment of native plant species was impeded by litter levels of 6000 kg/ha, the equivalent of approximately 4 years of pine litterfall. Both P. radiata and the two natives responded similarly to pine and eucalypt litter suggesting the two litter types are influencing the recruitment phase equally. However, where pines are added to the system, increased litterfall rates could potentially result in the doubling of the litter load and hence a greater barrier to seedling establishment. Pine invaded eucalypt woodlands are also subjected to three fold increases in canopy cover. Trends in reduced emergence of native species under a pine canopy suggest that the addition of pines to eucalypt forests is likely to have a negative influence on native recruitment and may result in a shift towards a shade tolerant community. However, reversal of trends in emergence below pine canopy between seasons implies that quantifying invasion impacts requires a consideration of temporal variation. Increased levels of disturbance, forest fragmentation and an increasing pine estate are likely to lead to the infestation of new areas. Furthermore the lag phase associated with pine spread means that even if no new plantations are established the number of invasion events will increase. This study has identified a number of risk factors that can be used to guide plantation establishment and the management of invasion events. Minimising disturbance at plantation borders and increasing the ‘no planting’ zone will help to reduce the impacts of pines. Where possible new plantations should be established upwind of cleared land or at least, wet sclerophyll forest. Frequent monitoring of the borders of plantations yet to source invasions, particularly those greater than 40 years of age, will help identify problem areas before control becomes difficult and costly. Maps of the 29 plantations marked with areas of pine infestation will help prioritise sites for control and provide base level knowledge for future monitoring of pine spread. Stringent legislation that binds plantation managers to control wildlings beyond their boundaries is critical for the effective management of pine invasions. With infinite numbers of invaders and limited funds to dedicate to their control, a method of triaging species for management is critical. This is particularly difficult viii when information is typically biased towards invaders that are already widespread. By focussing on the ecological impacts of invaders it becomes possible to rank species on the basis of the threat they pose to native communities. Ecological research is capable of providing the knowledge to quantify invasion impacts and must remain at the centre of policy decisions.

The aim of this thesis consist of three parts. Firstly, the aim was to developan accurate historical inflation index suitable for the insurance business, usinginformation about insurance matters. The calculated inflation index was compared to an in-house benchmark at the insurance company Gjensidige, it wasfound to be a good match. Secondly, to determine the best model for explainingthe Swedish CPI inflation shocks, the thesis employed Multi Linear, RandomForest and XGBoost Regression. Thirdly, feature importance estimation wasconducted to identify which macroeconomic variables that were the most important in explaining inflation. Also, a time lag analysis was implemented tobetter understand with what delay these features best explain the inflation. Theresults revealed that Random Forest and Multi Linear Regression were the mostsuitable model candidates in terms of performance and transparency based onthe available dataset. Furthermore, the study found that unemployment rate,interest rate, and energy were the most crucial features in explaining inflation.It was also found that features with a low time lag entailed a high importance.The belief is that the study’s findings can assist insurance companies in developing a more agile product pricing process and sharpen their awareness towardsimportant macroeconomic variables. Overall, this study can be a valuable resource for insurance companies seeking to avoid underwriting risk and gain abetter understanding of the inflation’s underlying drivers.

Membrane gas separation became an industrial reality in the late 1970s with Monsanto's first commercial asymmetric hollow fiber membrane modules. Innovations in membrane separations result from new materials that exhibit an improved permeability and are more selective than their predecessors, with materials commonly compared to the "upper bound line." Accurate determination of the three transport properties which characterize a membrane, permeability (P), diffusivity (D), and solubility (S), is thus of great interest to exceed the current upper bound line. Also, proper characterization of membrane materials enables enhancing current commercial membrane processes or allows for new applications. All three transport properties, P, S, and D, can be determined using a single dynamic gas permeation experiment in a constant volume (CV) system, commonly called the time-lag method. This work presents the next-generation CV system that utilizes the two-tank volume concept, namely a reference volume and a working volume. Compared to the previous iteration, the pressure in the reference volume can be reduced to the anticipated pressure in the working volume after initiating the gas permeation experiment. This allows monitoring of the pressure decay in the working volume (i.e., gas permeation into the membranes) using a high-resolution differential pressure transducer (DPT) right after initiating the experiment. The new system's operation is demonstrated by simultaneous monitoring of the upstream pressure decay and the downstream pressure rise during the time-lag experiments using a polyphenylene oxide (PPO) membrane. The values determined using the pressure decay method are compared to those determined using the downstream method to identify any limitations still present in the current iteration of the CV system. To set a reliable benchmark value to compare against, the downstream receiver was redesigned, and an optimal configuration was identified, which was associated with negligible resistance to gas accumulation and, thus, a minor error in the experimental time lag downstream from the membrane. Furthermore, a temperature enclosure was built to minimize errors caused by the constant temperature assumption during the time lag analysis. Additionally, the temperature-controlled enclosure allows for transport properties temperature dependence to be quantified by determining the activation energy of permeability, diffusion, and the enthalpy of solution for a given gas/polymer system.

Ce travail traite une investigation systématique des performances du procédé membranaire cyclique par séparation gazeuse. Premièrement, l'état de l'art du procédé membranaire cyclique, les problèmes techniques et la modélisation du transfert à travers la membrane ont été exposés. Deuxièmement, les études théoriques et expérimentales existantes sur le procédé cyclique sont passées en revue. Selon la durée de pression haute et sa fraction dans un cycle, ce genre d'opération est divisé en deux classes: classes courte et longue. D'après cette classification, une analyse systématique de l'intérêt potentiel de la classe courte par rapport aux performances d'une opération en régime permanent a été accomplie par des simulations et optimisations numériques. Par ailleurs, afin d'améliorer la performance, l'usage du MMM dans un tel procédé a été discuté. En parallèle à l'étude sur la classe courte, une nouvelle conception du procédé cyclique de classe longue a été proposée. Les avantages spectaculaires par rapport aux procédés membranaires classiques ont été mis en évidence à l'aide de nos simulations et optimisations. Finalement, une validation expérimentale a été effectuée afin de fournir un support solide à cette nouvelle conception / This study deals with a systematic investigation of the performance of cyclic membrane gas separation processes. First, a state of the art of membrane separation processes, including material challenges and mass transfer modeling issues is proposed. In a second step, a review of the different theoretical and experimental studies performed on cyclic processes is reported. With respect to the length of the high pressure stage and its fraction in one cycle, these operations are classified into short and long classes. Based on this classification, a systematic analysis of the potential interest of short class compared to steady-state operation performances has been achieved by means of numerical simulation and optimization. In order to improve the performance, the use of MMM in such a process has been further discussed. In parallel with the short class study, a design of novel long class has been proposed. Spectacular advantages with respect to classical membrane-based processes have been highlighted by means of our simulation and optimization studies. Finally, an experimental verification has been performed in order to provide a solid support to this novel process

During the radio therapy treatment, it has been difficult to synchronize the radiation beam with the tumor position. Many compensation techniques have been used before. But all these techniques have some system latency, up to a few hundred milliseconds. Hence it is necessary to predict tumor position to compensate for the control system latency. In recent years, many attempts have been made to predict the position of a moving tumor during respiration. Analyzing external breathing signals presents a methodology in predicting the tumor position. Breathing patterns vary from very regular to irregular patterns. The irregular breathing patterns make prediction difficult. A solution is presented in this paper which utilizes neural networks as the predictive filter to determine the tumor position up to 500 milliseconds in the future. Two different neural network architectures, feedforward backpropagation network and recurrent network, are used for prediction. These networks are initialized in the same manner for the comparison of their prediction accuracies. The networks are able to predict well for all the 5 breathing cases used in the research and the results of both the networks are acceptable and comparable. Furthermore, the network parameters are optimized using a genetic algorithm to improve the performance. The optimization results obtained proved to improve the accuracy of the networks. The results of both the networks showed that the networks are good for prediction of different breathing behaviors.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.