Dissertations / Theses on the topic 'Recovered fibre'

Energy utilization is a determining factor for the standards of living around the world, and the current primary source of energy is fossil fuels. A potential source of liquid fuels that could ease the strain caused by diminishing petroleum resources is bioethanol. Effective exploitation of biomass materials requires a pretreatment to disrupt the lignin and cellulose matrix. The pretreatment utilized for this research was oxygen delignification, which is a standard process stage in the production of bleached chemical pulp. The model substrate utilized as a feedstock for bioethanol was recovered fibre. An analysis of the substrates digestibility resulted in a hexose yield of approximately 23%, which justified the need for an effective pretreatment. An experimental design was performed to optimize the delignification conditions by performing experiments over a range of temperature, caustic loadings, and reaction times. Equations were developed that outline the dependence of various response parameters on the experimental variables. An empirical model that can predict sugar concentrations from enzymatic hydrolysis based on the Kappa number, enzyme loading, and initial fibre concentration was also developed. A study of hydrolysis feeding regimes for untreated recovered fibre (87 Kappa), pretreated recovered fibre (17 Kappa), and bleached pulp (6 Kappa) showed that the batch feeding regime offers reduced complexity and high sugar yields for lower Kappa substrates. In order to evaluate the possibility of lignin recovery, the pH of delignification liquor was reduced by the addition of CO₂ and H₂SO₄, resulting in up to 25% lignin yield. An experiment that looked at effect of post-delignification fibre washing on downstream hydrolysis found that a washing efficiency of approximately 90% is required in order to achieve a hexose sugar yield of 85%.

Les composites renforcés à fibres de carbone (CRFC) sont des matériaux de haute technicité appliqués à de nombreux domaines, du sport à l’aéronautique. Cette dernière décennie a vu leur demande croitre continuellement, générant en conséquence une augmentation du volume de déchets. Incités par les directives Européennes sur la gestion des déchets, des traitements thermiques de recyclage industriel ont été développés afin de récupérer les fibres de carbone issues des CFRC, principalement à matrice thermodurcissable. Actuellement, les CRFC en développement et/ou de dernières générations, utilisent des matrices thermostables telles que le Poly Ether Ether Cétone (PEEK). Une partie des travaux de thèse consiste à étudier la faisabilité de recyclage de ce composite thermostable, seul et en mélange avec d’autres types de composites à matrice thermodurcissable et thermoplastique. Un pilote semi-industriel a été employé sous atmosphères inerte (pyrolyse) et réactives (vapo-thermolyse et air). Les premiers résultats sur des mélanges ont montré que sous atmosphère inerte la récupération des fibres de carbone issues des matrices thermostables est quasi impossible. A l’inverse, les essais sur les composites PEEK en atmosphères oxydantes permettent l’extraction de la fibre mais induisent des modifications morphologiques et chimiques de la surface ainsi qu’une réduction de la résistance en traction. Les travaux de thèse se focalisent également sur des solutions alternatives de valorisation des fibres de carbone recyclées. Ces fibres ont été recouvertes de nanocellulose en tant qu’agent d’ensimage, en vue de leur réutilisation dans de nouvelles formulations. La perte de propriétés mécaniques induite par le recyclage a été partiellement compensée par ce traitement de surface. Des fibres recyclées ont également été incorporées dans un composite à renfort naturel de jute et matrice PA6 dans le but de créer un composite hybride offrant des propriétés équilibrées en termes de résistance, prix et impact écologique
Carbon Fiber Reinforced Composites (CFRC) are high technical materials applied in various fields from sports to aeronautics. During the last decade, the demand of CFRC has extended significantly resulting in increasing the volume of composite waste generated each year. Incited by European directives, thermal recycling treatments have been developed at industrial scale to recover carbon fibers, mostly from thermosetting composites. Nowadays CFRP in development used thermoresistant resins such as Poly Ether Ether Ketone (PEEK). Part of this work is to study the recycling feasibility of this type of CFRP alone and mixed with thermosetting and thermoplastics matrix based composites. Semi-industrial pilot was used in inert (pyrolysis) and reactive (steam-thermolysis, oxydation) atmosphere conditions. First results of mixture perform in nitrogen have revealed that inert atmosphere cannot allow the recovery of carbon fibers from thermoresistant resins. On the contrary trials on PEEK in oxydative atmospheres enable the extraction of fiber, but induce morphological and chemical modifications and tensile strength reduction. New approach on the recycled carbon fiber valorization have also been studied. These fibers have been coated by nanocellulose as sizing agent for their reuse in new composite formulations. Mechanical properties loss induce by recycling have been offset thank to this surface treatment. Recycled fibers was also incorporate in jute/PA6 composite to create a hybrid composite with balance properties in terms of strength, price and environmental impact

Abstract The amount of printing ink in a pulp suspension produced from recovered paper and its impact on overall brightness is commonly estimated from the reflectance-based ink content measured at a wavelength of 700 nm or 950 nm. The method uses a light scattering coefficient that can be measured from a slightly translucent test medium, i.e. of an opacity less than 97%. This is the case with machine-made papers in most instances. Alternatively, suitable opacity can be achieved by preparing a standard low-grammage sheet on a wire screen, but this results in poor retention of fibre fines, mineral fillers and printing inks, which is especially detrimental to ink measurement when the pulp suspension contains substantial amounts of printing inks. Hence opaque pads are often prepared on filter paper to achieve high retention. Unfortunately their high opacity prevents measurement of the light scattering coefficient, and thus a constant coefficient must be used for the determination of ink content. The aim of this thesis was to clarify the effects of retention and fine material changes on the light scattering coefficient in ink content measurement. The results showed that the light scattering properties of pulp in the wavelength region used for ink content analysis do not remain constant when the fine material content varies. The grade of the recovered paper, hyperwashing and flotation alter the fine material content and thus affect the light scattering. Printing ink also affects light scattering, but its practical impact is smaller than that of fibre fines and mineral fillers. The light scattering coefficient used for each ink content measurement needs to be representative, otherwise a systematic bias in ink content measurements may result from changes in the nature of the fine material and in its content. It is recommended that the light scattering coefficient should be measured in order to avoid this. The measurement should preferably be performed from a low-grammage sheet prepared on filter paper, as this ensures high retention and a measured value that represents better the initial state of the pulp suspension
Tiivistelmä Mustepitoisuusmittaus perustuu hajaheijastukseen joko 700 nm tai 950 nm aallonpituudella ja sitä käytetään usein arvioitaessa keräyspaperista valmistetun massasuspension soveltuvuutta painopaperien valmistukseen ja painomusteen vaikutusta massan vaaleuteen. Mustepitoisuuden mittauksessa käytetään valonsirontakerrointa, joka voidaan mitata hieman läpikuultavasta näytteestä eli näytteen opasiteetin on oltava pienempi kuin 97 %. Tämä opasiteettiraja toteutuu useimmiten paperikoneella tehdyille painotuotteille. Riittävän alhainen opasiteetti saavutetaan myös valmistamalla standardin mukainen matalaneliömassainen arkki viiralle, mutta tämä johtaa kuitumaisten hienoaineiden, mineraalisten täyteaineiden ja painomusteiden alhaiseen retentioon. Matala retentio on erityisen haitallinen piirre mustemittauksen kannalta massoilla, jotka sisältävät huomattavia määriä painomusteita. Siten usein valmistetaan läpikuultamattomia arkkeja suodatinpaperin päälle, joiden retentio on korkea. Korkeasta opasiteetista johtuen näistä arkeista ei voida määrittää valonsirontakerrointa, jolloin mustepitoisuuden määritys perustuu vakiokertoimeen. Tämän väitöskirjan tavoitteena oli selvittää retention ja hienoaineiden muutoksien vaikutuksia valonsirontakertoimeen ja mustemittaustulokseen. Tutkimuksen tulokset osoittivat että valonsirontakerroin, joka mitataan mustepitoisuuden yhteydessä, ei pysy vakiona hienoainepitoisuuden muuttuessa. Hienoainepitoisuuteen ja siten valonsirontakertoimeen vaikuttavat keräyspaperin laji, hyperpesu ja vaahdotus. Myös painomuste vaikuttaa valonsirontakertoimeen, mutta käytännössä vaikutuksen suurusluokka on pienempi kuin hieno- ja täyteaineilla. Mustepitoisuuden määrityksessä käytetyn valonsirontakertoimen on oltava edustava, muutoin arvot voivat olla systemaattisesti virheellisiä hienoainemäärän tai laadun muuttuessa. Virheen välttämiseksi olisi suositeltavaa määrittää valonsirontakerroin mustepitoisuusanalyysin yhteydessä. Tämä olisi mahdollista tehdä suodatinpaperin päälle valmistetusta matalaneliömassaisesta arkista, jolloin saavutetaan korkea retentio ja näin mitattu arvo edustaa paremmin massasuspension alkuperäistä tilaa

This work is concerned with the characterisation and reuse of fibres recovered from end of life thermoset composites by fluidised bed thermal processing. Emphasis is placed on the properties of recovered glass fibres and their reuse in a dough moulding compound and a tissue product. The need for a recycling process is demonstrated by a survey of the market for thermoset composites with particular consideration given to the potential growth in automotive applications. A study of processes developed to recycle such materials and the effect on the structural properties of composites containing such recyclate shows that a process capable of generating recyclate of greater value is required, particularly for the case of contaminated materials. A review of investigations into the effect of prior heat treatment on the mechanical properties of glass fibres shows that their strength will be reduced by a deterioration of the fibre surface during fluidised bed thermal recovery but that their stiffness is likely to be unaffected. The implications of these effects on possible applications for the recovered fibres are described. Tests are reported on the structural properties of laminates containing heat treated glass cloth which show that there is a strength reduction which is both time and temperature dependent but that modulus is not significantly affected. Strength loss increases with up to 20 minutes heating but then remains constant. In some cases the strength loss can be reduced by resizing the cloth. Measurement of the properties of fibres recovered using the fluidised bed process shows that the recovered fibre strength decreases with increasing processing temperature. Glass and carbon fibres recovered at 450°C retain approximately 50% and 80% of their virgin strengths respectively. The Young's modulus of the recovered fibres is shown to be largely unaffected by the process for both glass and carbon fibres. Investigation of the lengths of the recovered glass fibres by image analysis techniques suggests that their distribution depends on the structure of the composite and the method of size reduction. A weighted mean fibre length of 3.5 mm to 5.5 mm is possible with the apparatus described in this thesis. The reduced reinforcement potential of the recovered fibres is confirmed by experiment. Recovered glass fibres are used to displace virgin fibres in a dough moulding compound. At replacement levels of up to 50% there is no significant effect on the mechanical properties of a compression moulded plate. Above this level, tensile, flexural and impact strengths are reduced and with complete replacement the reduction is by approximately 40%, 50% and 70% respectively. These results are confirmed on a pilot plant scale. Recovered glass fibres can be successfully incorporated with virgin fibres into a veil. Replacement of virgin fibres reduces both wet and dry strength because the recovered fibres are both shorter and weaker. The permeability of the veil is found to depend on its porosity and not its recovered fibre content. The experimental veils can be used to protect and improve the surfaces of mouldings.

The objective of this work was to determine the influence of recovered fibres on the mechanical properties of board. Industrial board was provided by Fiskeby Board AB and laboratory board was made by using an isotropic sheet former. Board properties such as tensile strength, tensile stiffness, z-strength and bending stiffness were evaluated. Variation in the grammages of the middle and bottom layers of laboratory board was done and influence on the mechanical properties was studied. Each layer of multiply board was also tested separately at industrial board grammage and standard grammage. Results showed an increase in the tensile properties with the increase in the grammage of bottom layer, an increase in the z-strength of the board was also observed. Bending stiffness calculated by laminate theory also indicated an increase with the increase in the grammage of bottom layer. While testing of the separate layers showed an increase in the tensile properties of the layers with increasing the grammage while a decrease in z-strength was observed. Cracks occurred in the bottom layer of the multiply boards but an increase in the mechanical properties of board was observed.
Returfibrer är miljövänliga och ger ett försprång framför nyfiber på grund av låg kostnad. Det är dock allmänt känt att returfibrer inte uppvisar samma egenskaper som nyfibrer, i själva verket försämras fiberegenskaperna efter varje återvinningsprocess. Mekaniska egenskaper är mycket viktiga för kartongproducenter och därmed läggs en hel del energi på förbättringar utan kostsamma investeringar.   I detta examensarbete utvärderades mekaniska egenskaper för 4-skikts kartong såsom dragstyrka, dragstyvhet, böjstyvhet och z-styrka. Den industriella kartongen som användes kom från Fiskeby Board AB och laboratoriekartong tillverkades med en isotrop arkformer. Separata skikt formades och guskades därefter samman. Ytvikten av det mellersta och undre skiktet ändrades och effekten på kartongens egenskaper utvärderades. Varje lager testades också separat vid ytvikter representativt för den industriella kartongen samt vid standardiserade ytvikter. Styrkan i tjockleksriktningen utvärderades med z-styrka och Scott Bond. Böjstyvheten beräknades med hjälp av laminatteorin.   Skillnaderna i dragstyrka mellan kartong framställd i industrin och laboratorie var små, men dragstyvheten var lägre för laboratoriearken på grund av torktekniken. Skillnaderna i z-styrka var inte signifikanta, men baserat på trenden uppvisade laboratoriearken en lägre styrka på grund av ett lägre presstryck. Delamineringen i de testade proverna skedde i det undre skiktet och inga sprickor uppstod mellan skikten.   Genom ökning av ytvikten av de separata skikten ökade styrkeegenskaper såsom dragstyrka och Scott Bond medan z-styrkan minskade. Genom att minska ytvikten av det mellersta lagret och öka ytvikten av det nedre kunde en ökning av styrkeegenskaperna observeras. Ökningen av z-styrkan var inte signifikant men baserat på trenden kan en ökning förväntas. En betydande ökning av Scott Bond kunde dock ses. Böjstyvheten beräknad genom laminatteorin visade också på en ökning. Även om sprickor fortfarande förekommer i det undre skiktet efter ökning av ytvikten, kan förbättrade kartongegenskaper uppnås.

This work has included a review of the most relevant aspects of measurement techniques and mathematical models proposed in the literature to assess the equilibrium and mass transfer data of metal extraction by the use of chelating agents. The limitations of these techniques and models have been highlighted. Three chelating extractants diluted in EscaidllO were used to study the extraction equilibrium of copper. The extractants are 5-nonylacetophenone oxime (LIX84®), 5- dodeylsalicylaldoxime (LIX860®) and 50/50 v/v mixture of both oximes (LIX984®). The copper concentration changes in the aqueous and the organic phases were monitored by using atomic absorption spectrophotometer. Two mathematical models (a chemical model and a semi-empirical model) have been developed in this study to predict the equilibrium data of copper sulfate/hydroxyoxime system. The chemical model was found to fit all the three equilibrium systems (CuSO4/LIX84®, LIX860®and LIX984®) equally. The semi-empirical model based on Freundlich's adsorption equation was also found to fit the three systems but with less accuracy. The mass transfer characteristics and properties of copper extraction and recovery from an aqueous solution using LIX984® were studied using dispersion-based (rising drops) and dispersion-free techniques. In the dispersion-based technique the organic phase was dispersed in form of drops at the tip of hypodermic needle while the aqueous solution was used as a continuous phase. The extraction process was carried out in four different height columns under wide range of conditions. The effects of the columns' height, the dispersed and the continuous phases concentrations on the metal rate of mass transfer were investigated. It has been found in that the metal's rate of mass transfer and system's overall mass transfer coefficient have remained constant in all four columns. A model utilising the two-film theory, some of the dimensionless groups and the experimental results has been proposed in this work to calculate the local mass transfer coefficients in the dispersed phase and the continuous phase. The overall mass transfer coefficient and the calculated local coefficients were used to account for the reaction rate constant at the interface from the sum of the individual resistances to mass transfer. A dispersion-free technique consisting of a microporous hollow fibre module was used in this study to examine the mass transfer properties of the extraction and stripping processes of copper across an immobilised interface system. The extraction and re-extraction (stripping) processes in this system were conducted under a wide range of operating conditions and produced satisfactory results. In general it has been found that counter current flow arrangement gave higher concentration driving forces which were reflected in form higher metal concentrations at the extract phase. A generalised mathematical model was developed in this study which utilised Wilson's method, the experimental data, some dimensionless groups and the two-film theory to account for local resistances and predict the system's overall mass transfer coefficient. A correlation was established first to calculate mass transfer coefficients using a form of Leveque's equation which relates the two phase's physical properties and the system's parameters. The membrane mass transfer coefficient was calculated from the structural properties of the membrane material. While the resistance at the reaction interface was calculated under set of experimental conditions. The individual coefficients were then used to predict the overall mass transfer coefficient under any set of conditions by using the aditivity approach of the individual resistances to mass transfer. However, further checks and investigations are necessary to validate this model over variety of extraction systems and membrane configurations.

Fire activity, in terms of intensity, frequency, and total area burned, is expected to increase with a changing climate. A challenge for landscape-level assessment of fire effects, often termed burn severity, is that current remote sensing assessments provide very little information regarding tree/vegetation physiological performance and recovery, limiting our understanding of fire effects on ecosystem services such as carbon storage/cycling. In this paper, we evaluated whether spectral indices common in vegetation stress and burn severity assessments could accurately quantify post-fire physiological performance (indicated by net photosynthesis and crown scorch) of two seedling species, Larix occidentalis and Pinus contorta. Seedlings were subjected to increasing fire radiative energy density (FRED) doses through a series of controlled laboratory surface fires. Mortality, physiology, and spectral reflectance were assessed for a month following the fires, and then again at one year post-fire. The differenced Normalized Difference Vegetation Index (dNDVI) spectral index outperformed other spectral indices used for vegetation stress and burn severity characterization in regard to leaf net photosynthesis quantification, indicating that landscape-level quantification of tree physiology may be possible. Additionally, the survival of the majority of seedlings in the low and moderate FRED doses indicates that fire-induced mortality is more complex than the currently accepted binary scenario, where trees survive with no impacts below a certain temperature and duration threshold, and mortality occurs above the threshold.

Cette étude porte sur l'effet de l'ozone introduit en flottation en vue d'optimiser le désencrage des fibres récupérées pour la production de papier de forte blancheur : amélioration des propriétés optiques des fibres recyclées et réduction de l'impact environnemental des rejets du désencrage. Un pilote de flottation couplé à un générateur d'O3 a été développé et validé dans des conditions classiques de flottation à l’air. L'effet de O3 sur l’opération de désencrage a été étudié pour deux types de papiers récupérés (impression offset et mélange 50/50 de journaux/magazines). L’introduction d’O3 en flottation conduit à une amélioration de l’élimination de l’encre, à une légère diminution de la production de boues de désencrage et à la dégradation partielle des azurants optiques ce qui accroît l'aptitude au contact alimentaire de la pâte désencrée. De plus, la DCO des effluents est réduite de plus de 25%. Ces résultats montrent que la flottation réactive à l'O3 est une solution prometteuse pour améliorer l’efficacité du désencrage et diminuer la pollution de ses rejets
This work studied the effect of ozone used as a reactive gas in flotation in order to optimise recovered cellulosic fibre deinking for the production of high brightness paper : improvement of the recycled fibre optical properties and reduction of the flotation rejects. A flotation pilot, coupled with an ozone generator, was developed and validated in the conventional air flotation operating conditions. The effect of ozone on the deinking process was studied for two recovered paper furnishes (offset prints and a mixture of 50/50 newsprints and magazines). The introduction of ozone led to the increase of ink removal, to a slight reduction of the deinking sludge production and to the partial degradation of the optical brighteners which improves the food-contact ability of deinking pulps. Moreover, the COD of the effluents is reduced by more than 25 %. These results showed that the ozone reactive flotation is a promising solution to improve the deinking efficiency and to decrease the pollution of its rejects

Biocrusts and the ecosystem services they provide are becoming more susceptible to fire as exotic annual grass invasions facilitate the spread of desert wildfires. Further, precipitation patterns across the western United States are predicted to change over the next century, and have the potential to dramatically influence fire regimes and the recovery of burned biocrusts. Despite these changes to desert fire and precipitation cycles, our understanding of post-fire biocrust recovery is limited, especially regarding the first two years after fire. To investigate biocrust recovery, we created burn manipulations (i.e., unburned and burned) and tracked crust form and function over two years in one cold and one hot desert ecosystem (UT, USA). We evaluated the entire bacterial community, but focused on Cyanobacteria species that confer soil stability and N fixation capabilities to biocrusts. Specifically, we quantified shifts in biocrust bacterial community composition using target metagenomics of 16S rDNA; monitored biocrust moss and lichen cover; measured N fixation potential; and assessed soil infiltration rates and soil stability. We found little evidence that biocrust form or function recovered from fire within two years. Based on pyrosequencing results, fire altered biocrust community composition in interspace and shrub biocrusts. Cyanobacteria species were almost completely eliminated by fire, constituting 9-21% of unburned plots and less than 0.01% of burned interspace and shrub biocrust communities. Based on cover estimates, no lichen or moss species survived the fire or recovered within two years. N fixation potentials decreased by at least six-fold in burned interspace biocrusts, representing a reduction in soil N inputs into already N-limited desert soils. Soil infiltration rates also drastically declined in burned biocrusts and remained depressed, but only remained depressed for one year. To investigate the interactions between biocrust recovery, fire, and precipitation, we nested precipitation treatments manipulating the amount of monthly rainfall (i.e., ambient, plus 30% and minus 30%) within burn treatments during the second year. Soil NH4+ was the only parameter to be affected by precipitation, and exhibited a positive relationship with precipitation magnitude at the end of one year. Our results demonstrate that fire is a strong destabilizer of the bacterial components of biocrust communities and that the ecosystem services provided by crusts recover at different rates, with N dynamics recovering more slowly than soil ecohydrology.

Growth in response to trauma (Posttraumatic growth – PTG) has been established in a number of studies, though only two (Hewitt 2004, McMillen et al 2001) are directly related to the traumatic experience of addiction to drugs and alcohol. This study built on previous work by the author (Hewitt 2002, 2004) that established that addiction could be seen as a trauma, and that both negative and positive effects could result from the experience. This research sought to explore the experience of posttraumatic growth in recovery from addiction. The aim was to clarify more explicitly the experiences of some of the people who reported PTG in relation to addiction, increasing our awareness and understanding of some of the outcomes, strategies and processes involved, and the implications of these findings. The research comprised two studies. In the first, the experience of 16 people who felt they had PTG effects resulting from their previous addiction to drugs or alcohol was analysed using Grounded Theory. In the second study, the experience and views of another three people who fulfilled the same criteria but in addition were also ‘experts’ in this area were analysed using Interpretative Phenomenological Analysis. Combining the data analysis from both studies described a uniquely personal overall process of individuation, with growth along a developmental continuum from addiction recovery to thriving resulting from the deliberate use and generation of recovery capital and growth capital. There were a large range of positive feedback loops that supported this growth, and meaning was of central and ongoing importance. The study findings were compared to the wider PTG literature and found to have much in common, further supporting the view that addiction can be seen as a stressor in PTG terms, and suggesting that there may be much theory and practice from the PTG field that can be applied to the area of addiction recovery. Limitations of the study are discussed, and recommendations made for further testing of the model developed within the thesis in order to examine its generalisability, as well as for study and theory development, and for the development of policy and practice relating to promoting recovery from addictions and subsequent growth.

A new concept of a "fiber sorbent" has been investigated. The fiber sorbent is produced as a pseudo-monolithic material comprising polymer (cellulose acetate, CA) and zeolite (NaY) by applying hollow fiber spinning technology. Phase separation of the polymer solution provides an appropriately porous structure throughout the fiber matrix. In addition, the zeolite crystals are homogeneously dispersed in the polymer matrix with high loading. The zeolite is the main contributor to sorption capacity of the fiber sorbent. Mass transfer processes in the fiber sorbent module are analyzed for hydrogen recovery and compared with results for an equivalent size packed bed with identical diameter and length. The model indicates advantageous cases for application of fiber sorbent module over packed bed technology that allows system downsizing and energy saving by changing the outer and bore diameters to maintain or even reduce the pressure drop. The CA-NaY fiber sorbent was spun successfully with highly porous structure and high CO2 sorption capacity. The fiber sorbent enables the shell-side void space for thermal moderation to heat of adsorption, while this cannot be applied to the packed bed. The poly(vinyl alcohol) coated CA-NaY demonstrated the thermal moderation with paraffin wax, which was carefully selected and melt at slightly above operating temperature, in the shell-side in a rapidly cycled pressure swing adsorption. So this new approach is attractive for some hydrogen recovery applications as an alternative to traditional zeolite pellets.

Abstract Paper recycling is an ecological strategy for disposing of waste paper, but more importantly, recovered paper is an important source of raw material in the paper and board industry. Deinked pulp production from recovered paper has proved economically viable by comparison with virgin fibre pulp manufacturing, but this viability is now threatened by increasing waste disposal costs, as up to 25% of the raw material available for deinked pulp production can end up in the reject streams, which then have to be disposed of. The most common practice at present is incineration and disposal of the resulting ash in landfills, but tightening legislation has meant that landfills have become very expensive and are likely to be completely banned in the near future. Thus new ways have to be sought for managing the waste problem in deinked pulp production in order to ensure that the recycled paper production remain both economically and environmentally feasible. The aim of this thesis was to study means of improving the material efficiency of a deinked pulp mill without excessively detracting from end product quality or the performance of the combined sludge dewatering stage. First, an analytical procedure was developed for determining the utilisation potential of reject streams, and a considerable potential for material recovery from these streams was identified. The results presented here show that 80% of the most valuable long fibres from the fine-screening rejects and 15% of the fine material from the flotation froth reject can be recovered. Altogether, with the simultaneous recovery of both categories of reject, it would be possible to improve the material efficiency at the deinked pulp mill by a total of about 5 percentage units, which can be considered significant for process efficiency. Moreover, this would enable the fibre content of the combined sludge to be kept above a certain limit, so that the combined sludge dewatering properties would not be affected. Consequently, the results presented in this thesis provide several widely applicable means for improving the resource efficiency of a deinked pulp mill
Tiivistelmä Paperin kierrätys uusiksi paperituotteiksi on ympäristöystävällinen tapa jätepaperin käsittelemiseksi. Uusiomassan valmistus on myös taloudellisesti kannattavaa verrattuna paperimassan valmistukseen neitseellisistä raaka-aineista. Taloudellinen kannattavuus on kuitenkin vaarassa jätemaksujen alati kasvaessa, sillä siistausmassan valmistuksessa jopa 25 % kierrätyspaperiraaka-aineesta päätyy jätejakeisiin, jotka hävitetään yleisesti polttamalla ja läjittämällä syntynyt tuhka kaatopaikalle. Lainsäädäntö on rajoittanut kaatopaikkasijoittamista ja se on nykyään hyvin kallista. Tulevaisuudessa jätteiden kaatopaikkasijoittaminen voi olla jopa täysin kiellettyä. Jäteongelman ratkaisemiseen tarvitaan siis uusia menetelmiä, jotta kierrätyspaperin valmistus säilyisi sekä taloudellisista että ympäristöllisistä näkökulmista kannattavana toimintana. Tämän väitöskirjatyön tavoitteena oli etsiä keinoja parantaa siistausmassan valmistuksen resurssitehokkuutta palauttamalla käyttökelpoisia materiaaleja jätevirroista takaisin prosessiin siten, ettei heikennetä lopputuotteen laatua eikä lietteidenkäsittelyprosessin toimintaa. Väitöstyön alussa kehitettiin analyysiproseduuri rejektivirtojen hyötykäyttöpotentiaalin arvioimiseksi ja siistamon rejektijakeissa havaittiin merkittävästi hyödynnettävää materiaalia. Tulokset osoittavat, että 80 % hienolajittelun rejekteissä poistuneista arvokkaista pitkistä kuiduista voidaan palauttaa takaisin prosessiin. Lisäksi flotaation vaahtorejektistä voidaan palauttaa 15 % hienoainetta. Palauttamalla yhtäaikaisesti sekä kuituja hienolajittelun rejekteistä että hienoainetta flotaation vaahtorejektistä, voidaan siistausmassan valmistuksen materiaalitehokkuutta parantaa yhteensä noin 5 prosenttiyksikköä, mikä on merkittävä parannus prosessitehokkuuteen. Kuitujen ja hienoaineen samanaikainen palauttaminen pitää lisäksi lietteiden käsittelyssä seoslietteen kuitupitoisuuden tarpeeksi korkeana, jotta sen vedenerotusominaisuudet säilyvät hyvinä. Tämän tutkimuksen tuloksena löydettiin siis useita laajalti sovellettavissa olevia keinoja siistausmassan valmistuksen resurssitehokkuuden parantamiseksi

In mountains throughout western North America, large, mixed-severity fires produce a mosaic of low and high tree mortality. Following wildfire, plant communities may recover to their pre-fire state, or may remain altered in composition and structure. In this study I quantified the extent to which fire severity influenced post-fire vegetation composition and structure in comparison to pre-fire states in the Santa Catalina Mountains, Arizona, USA. I used a stratified random design that sampled plots across ecological units and fire severity classes. Tree diameter at breast height (DBH), shrub cover, and seedling and sapling density was recorded by species in five plant communities: oak/pinyon/juniper woodland on hills landscapes of mixed lithology; Madrean pine-oak forest/woodland on granite, gneiss, or metasedimentary rock; Madrean oak/conifer/manzanita on rock outcrops; ponderosa pine forest on granite, gneiss, and similar rocks; and mixed conifer forest on metasedimentary landscapes. Subsets of these data were then used to reconstruct overstory vegetation present when the Bullock (2002) and Aspen (2003) fires occurred. Data from a 1984 pre-fire study was used to substantiate the overstory reconstruction and to determine shrub understory components. I tested the hypothesis that tree mortality was a determinant of post-fire shrub cover, and calculated post-fire importance values (IVs) of tree and shrub components. Ordination and non-metric multidimensional scaling (NMS) of IVs confirmed that overstory reconstruction aligned with 1984 field surveys. Tree mortality was a predictor of post-fire shrub cover, but only with certain species in specific ecological units. Ordinations indicated that tree composition in post-fire plots has diverged from that in pre-fire plots in all but the oak/ pinyon/juniper community. Ordination of shrub components indicated novel configurations of post-fire communities, including association of pre-fire mixed conifer elements with oak woodland elements. The intermixing of tree species in mid- and higher-elevation communities with those historically confined to lower elevation community types suggests that recent fires has disrupted vegetation inertia and initiated novel ecological change. The re-structuring observed within these community types are in agreement with projections that disturbance and climate change will interact to facilitate the spread of lower elevation species to higher elevation zones. Fire x climate interactions may therefore trigger long-lasting changes to ecosystem structure in ways not predicted by models of fire-effects or climate-effects occurring in isolation from each other.

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol)
Namaqualand Granite Renosterveld (NGR) is a fire-prone shrubland largely confined to the Kamiesberg Uplands. More than 20% has been transformed by agricultural activities such as grazing and dryland cropping. The history of fires of Namaqualand Granite Renosterveld was assessed over a period from 2000 - 2015. Furthermore, this study aimed to assess the effects of fire and grazing on the dynamics of Elytropappus rhinocerotis and the post-fire vegetation recovery. Satellite imagery, field observations and combination of field sampling techniques were used to compile a comprehensive fire database and to collect data on vegetation parameters. The Kamiesberg Uplands has a human-induced fire regime with a fire frequency of 4.2 years, which appears to be shorter for NGR compared to other Renosterveld - types. The majority of the fires were in summer and early autumn which is the ecologically accepted season with high fire intensities. Fire Danger Index ratings for summer burns were in the dangerous and very dangerous categories. In terms of cover, the distances between E. rhinocerotis individuals were significantly more on the burnt than on the unburnt sites. The density of unpalatable species on the burnt sites is also strongly associated with E. rhinocerotis. Elytropappus rhinocerotis appears to facilitate a role as a nurse-plant for various species in renosterveld. The local biotic and abiotic conditions, allows E. rhinocerotis to maintain its abundance, thus displaying niche construction by a single species.
2020-08-31

Reducing losses of usable waste fiber from paper mills conserves valuable resources and has the capacity to produce considerable economic returns to the manufacturer. The purpose of this research effort was to evaluate the potential for the prevention of loss and/or recovery of usable waste fiber from paper machines within a fine paper mill. Further, a preliminary evaluation of fiber loss prevention strategies and fiber recovery technologies was conducted.

The paper mill in question experienced losses of usable waste fiber to the sewer in amounts approaching, and sometimes exceeding 40 tons/day. An existing database of usable fiber test results was analyzed to determine patterns of fiber loss. Further testing showed that the most significant fiber losses resulted from centrifugal cleaner cones. These cones, designed to remove foreign material from stock, are one step in a series of mechanical cleaning devices in the stock preparation area of the paper mill. Cleaner cone systems on two of the paper machines were found to contribute most significantly to total fiber loss.

Contrary to cleaner cone design, the dirt content of fiber rejects from cones experiencing excessive loss was very low. Cleaner cones on other machines operated normally. These rejects were extremely dirty and quantities of fiber were low. These results indicate poor operating efficiency of two of the cleaner cone systems in question. By adding cones where space is available, system capacity and efficiency will increase, fiber losses will decrease, and the dirt content of rejects will increase. This will result in substantial resource and financial savings to the paper mill.

Technologies have been developed to recover usable fiber from paper mill sludge. However, prior to further investigation of the use of such innovations at this paper mill, efforts should focus on the reduction of fiber loss from point sources.
Master of Science

L’objectif de cette étude est d’accroître les connaissances de l’effet de l’ozone introduit comme gaz réactif dans le procédé de flottation sur les performances du désencrage de papiers imprimés ainsi que sur les propriétés papetières des fibres cellulosiques recyclées (propriétés physiques et optiques, aptitude papetière). Des essais à forte dose d’ozone (2,97% par rapport à la masse de fibres) ont été investigués et conduits dans une cellule de flottation pilote de laboratoire (15 L). Plusieurs mélanges de papiers récupérés ont été étudiés : (i) un mélange 50%/50% magazines/journaux, (ii) deux mélanges modèles à base de fibres vierges sans bois (taux de lignine inférieure à 15%) pour limiter l’effet du jaunissement des fibres lignifiées, et (iii) un mélange industriel sans bois composé de 90% de papiers de bureaux et 10% de magazines. L’eau du réseau et une eau de procédé modèle ont été utilisées pour diluer les fibres avant désencrage. Pour une meilleure compréhension de la réactivité de l’ozone, des essais ont également été conduits sur les deux types d’eaux, en l’absence de fibre. Les principaux avantages du procédé de flottation réactive à l'ozone sont (1) la forte réduction de la DCO soluble dans les effluents jusqu’à 63% par rapport à la flottation à l’air dans le cas d’essais avec des papiers industriels, en utilisant une eau de procédé modèle, (2) l’augmentation du rendement en fibres de 1 point et (3) une conservation ou amélioration des propriétés papetières des fibres recyclées. L’ozone réagit préférentiellement avec les contaminants solubles de sorte que les fibres ne sont pas affectées.Ce procédé est tout à fait adapté au désencrage de papiers imprimés sans bois
The objective of this study is to broaden the knowledge about the effect of ozone, when introduced as a reactive gas in the flotation cell, on the deinking performance of printed papers as well as on the papermaking properties of recycled cellulosic fibers (physical and optical properties, papermaking ability). Trials, with high ozone dose (2.97% ozone/fibers w/w), have been investigated and conducted in a laboratory flotation cell pilot (15 L). Several mixtures of recovered papers have been studied: (i) an industrial mix made of 50%/50% magazines/newspapers, (ii) two wood-free recovered lignocellulosic fiber pulp models (lignin content lower than 15%) to limit the yellowing effect of lignified fibers, and (iii) a wood-free industrial pulp mixture composed of 90% office papers and 10% magazines. Tap water and model process water have been used to dilute the fibers before deinking. For a better understanding of the ozone reactivity, experiments have been also conducted on both types of waters in the absence of fiber. The main benefits of the ozone reactive flotation process are (1) the strong reduction of the effluent soluble COD of about 63% compared to air flotation in the case of the industrial pulp mixture deinking using the model process water, (2) the increase of the fiber yield by 1 point and (3) the preservation or the improvement of the papermaking properties of the recycled fibers. Ozone preferentially reacts with soluble contaminants, so that fibers and pulp papermaking properties are not affected. This process is utterly suitable for the deinking of wood-free papers

Thesis (M.S.)--Boston University
The ability to recognize and identify skeletal material is a fundamental skill in forensic and physical anthropology. Understanding the process that remains have undergone when they have been exposed to a fire environment necessitates further study and specialization as the basic structure of a bone may be altered from the microscopic level to the overall morphology. Analysis of burnt bone goes beyond understanding how the normal taphonomic processes may affect skeletal remains to the specifics of heat and fire related changes. Additionally, the study of how heat or fire alteration affects trauma determinations can be important for determining the forensic significance of a case. The procedures of a fire investigation play a very important role in the recognition, preservation and analysis of skeletal remains especially considering site recovery techniques and perimortem trauma interpretation determination. This study utilized whole pigs to document changes to trauma from exposure to a compartment fire. The results were compared to previous studies done on individual skeletal elements to show that trauma was still recognizable and often protected in the postcranial body.

The forests of south-eastern Australia, having evolved in one of the most fire-prone environments in the world, are characterized by many adaptations to recovery following burning. Thus forest ecosystems are characterized by rapid regenerative capacity, from either seed or re-sprouting, and mechanisms to recover nutrients volatilized, including an abundance of N2 fixing plants in natural assemblages. Soil physical, chemical and biological properties are directly altered during fire due to heating and oxidation of soil organic matter, and after fire due to changes in heat, light and moisture inputs. In natural ecosystems, carbon (C) and nitrogen (N) lost from soil due to fires are recovered through photosynthesis and biological N2 fixation (BNF) by regenerating vegetation and soil microbes.
This study investigated post-fire recovery of soil C and N in four structurally different sub-alpine plant communities (grassland, heathland, Snowgum and Alpine ash) of south-eastern Australia which were extensively burnt by landscape-scale fires in 2003. The amount and isotopic concentration of C and N in soils to a depth of 20 cm from Alpine ash forest were assessed five years after fire in 2008 and results were integrated with measurements taken immediately prior to burning (2002) and annually afterwards.
Because the historical data set, comprised of three soil samplings over the years 2002 to 2005, consisted of soil total C and N values which were determined as an adjunct to 13C and 15N isotopic studies, it was necessary to establish the accuracy of these IRMS-derived measurements prior to further analysis of the dataset. Two well-established and robust methods for determining soil C (total C by LECO and oxidizable C by the Walkley-Black method) were compared with the IRMS total C measurement in a one-off sampling to establish equivalence prior to assembling a time-course change in soil C from immediately pre-fire to five years post-fire. The LECO and IRMS dry combustion measurements were essentially the same (r2 >0.99), while soil oxidizable C recovery by the Walkley-Black method (wet digestion) was 68% compared to the LECO/IRMS measurements of total C. Thus the total C measurement derived from the much smaller sample size (approximately 15 mg) combusted during IRMS are equivalent to LECO measurement which require about 150 mg of sample.
Both total C and N in the soil of Alpine ash forests were significantly higher than soils from Snowgum, heathland and grassland communities. The ratio of soil NH4+ to NO3- concentration was greater for Alpine ash forest and Snow gum woodland but both N-fractions were similar for heathland and grassland soils. The abundance of soil 15N and 13C was significantly depleted in Alpine ash but both isotopes were enriched in the heathland compared to the other ecosystems. Abundance of both 15N and 13C increased with soil depth.
The natural abundance of 15N and 13C in the foliage of a subset of non-N2 fixing and N2 fixing plants was measured as a guide to estimate BNF inputs. Foliage N concentration was significantly greater in N2 fixers than non-N2 fixers while C content and 13C abundance were similar in both functional groups. Abundance of 15N was depleted in the N2 fixing species but was not significantly different from the non-N2 fixers to confidently calculate BNF inputs based on the 15N abundance in the leaves.
The total C pool in soil (to 20 cm depth) had not yet returned to the pre-fire levels in 2008 and it was estimated that such levels of C would be reached in another 6-7 years (about 12 years after the fire). The C and N of soil organic matter were significantly enriched in 15N and 13C isotopes after fire and had not returned to the pre-fire levels five years after the fire. It is concluded that the soil organic N pool can recover faster than the total C pool after the fire in the Alpine ash forests.

In this dissertation I investigated a multi-channel and multi-bit rate all-optical clock recovery device. This device, a birefringent Fabry-Perot resonator, had previously been demonstrated to simultaneously recover the clock signal from 10 wavelength channels operating at 10 Gb/s and one channel at 40 Gb/s. Similar to clock signals recovered from a conventional Fabry-Perot resonator, the clock signal from the birefringent resonator suffers from a bit pattern effect. I investigated this bit pattern effect for birefringent resonators numerically and experimentally and found that the bit pattern effect is less prominent than for clock signals from a conventional Fabry-Perot resonator.I also demonstrated photonic balancing which is an all-optical alternative to electrical balanced detection for phase shift keyed signals. An RZ-DPSK data signal was demodulated using a delay interferometer. The two logically opposite outputs from the delay interferometer then counter-propagated in a saturated SOA. This process created a differential signal which used all the signal power present in two consecutive symbols. I showed that this scheme could provide an optical alternative to electrical balanced detection by reducing the required OSNR by 3 dB.I also show how this method can provide amplitude regeneration to a signal after modulation format conversion. In this case an RZ-DPSK signal was converted to an amplitude modulation signal by the delay interferometer. The resulting amplitude modulated signal is degraded by both the amplitude noise and the phase noise of the original signal. The two logically opposite outputs from the delay interferometer again counter-propagated in a saturated SOA. Through limiting amplification and noise modulation this scheme provided amplitude regeneration and improved the Q-factor of the demodulated signal by 3.5 dB.Finally I investigated how SPM provided by the SOA can provide a method to reduce the in-band noise of a communication signal. The marks, which represented data, experienced a spectral shift due to SPM while the spaces, which consisted of noise, did not. A bandpass filter placed after the SOA then selected the signal and filtered out what was originally in-band noise. The receiver sensitivity was improved by 3 dB.

This study comprises characterization of fibres based on derivatised polyacrylonitrile, and investigation of their use as ion-exchange media. Physico-chemical and mechanical properties of fibres and fabrics made therefrom were determined. Dry fibres were non-porous, of high specific surface area (>10⁵m²/m³), with densities (1.35-1.6 g/cm³ higher than those of typical particulate exchangers (PEs). Fibres absorbed less water (40-60 vol%), than comparable PEs (100 vol%). Mechanical properties of fibres were affected by derivatisation and absorption of water. Fabrics were possessed low effective pore radii (<10^-5m) and high voidages (>0.7), and formed compressible beds whose characteristics were subject to control by external pressure. Effective exchange capacities of fibres fell within the range 0-4.5mmol/g, reaching maximum for fibre Actilex A301, (~ 45% of that of a PE incorporating similar active groups). This capacity varied as a function of pH, in a manner consistent with weak-acid behaviour. This fibre possessed an effective capacity for zinc at neutral pH of ~ 1.6mmol(Zn)/g. A three-stage recovery and regeneration cycle was found to effect repeatable and reproducible behaviour. Thin beds of A301 (<25mm), used to absorb zinc in an ion-exchange column, removed all influent zinc at very high flowrates, (>1000 bed volumes (BV)/hr). Transfer of zinc into exchange media was simulated using a model involving radial diffusion during axial advection and diffusion into the media, to produce breakout curves for beds, which were in reasonable agreement with experimental data. Ionic diffusivities within fibres were estimated from comparison of the model with experimental data and found to be less than those in PEs. Various comparisons of likely performance of beds of fibres and PEs demonstrated that fibrous beds have some advantages over those of PEs. The potential exploitation of these in continuous forms of fabric (and processes) are considered.

Traumatic spinal cord injury (SCI) is a devastating clinical condition that affects approximately 2.5 million patients across the world with 130,000 new injures being reported each year. Advances in research have provided better understanding of the complex pathophysiology after spinal cord injury, but so far no effective treatment has been able to provide functional recovery. Utilizing principles of tissue engineering, incorporation of a tubular implant at site of injury has gained considerable attention in recent years. The mechanical strength of the tubular implant, proposed for incorporation at site of injury, is very important for efficacy of the implant. In this project we have fabricated different types of hollow fiber channels (HFCs) with a porous morphology using dip-coating and sub-critical CO2 process. The HFCs have been characterized, their mechanical properties have been tested in vitro and their degradation behaviour over time has been analyzed. Among the different types of HFCs tested for mechanical properties, single layered, double layered and reverse porosity, presence of porosity gradient and its orientation plays an important role towards establishing the mechanical strength of the HFC. The porosity gradient results from the difference in pore sizes between the inner and the outer layer of the HFC. During our study we were able to satisfy two crucial parameters regarding the mechanical strength of the HFC. Firstly, it is important for the HFC to match its mechanical strength with that of spinal cord tissue and secondly, the ability of the HFC to possess optimal weight to avoid damage to the already injured tissue. Thus we were able to fabricate a tubular implant that has desired mechanical properties to be used after SCI.

The purposes of this dissertation were to examine the effect of a protein and carbohydrate recovery beverage versus a placebo on weightlifting performance, its effect on muscle morphological changes and specific muscle protein accretion. The following are major finding from the dissertation: 1) Protein and carbohydrate recovery supplementation does not appear to have influence on performance measure in trained weightlifters. This finding may be associated with the short-term nature of this study and the trained population used. 2) Compared with placebo, a protein and carbohydrate beverage provided greater benefits on cross sectional area of type I and type II muscle fibers. Additionally, the block periodization protocol incorporating phase potentiation improved cross sectional area of both groups compared to baseline. 3) Finally, protein and carbohydrate supplementation provided greater benefits on total mTOR and myosin heavy chains 6 & 7. These findings indicate that a protein and carbohydrate beverage provide greater benefits compared with a placebo on cellular signaling, myosin heavy gene expression and muscle fiber increases in trained weightlifters. Improved cross sectional area and increased myosin heavy chains indicate positive adaptations to resistance training combined with supplementation and may indicate improved skeletal muscle qualities necessary for increased power output. The mTOR pathway is the master regulator of cellular growth and increases in total mTOR indicate a greater proclivity for cellular growth and greater activity resulting from resistance training may increase synthesis and accretion of muscle contractile proteins. This dissertation highlighted several benefits of recovery supplementation, however further longitudinal studies utilizing block periodization and well-trained athletes are necessary to fully elucidate benefits for strength and power athletes.

Mestrado em Geomateriais e Recursos Geológicos
Remote Sensing has been used for decades, and more and more applications are added to its repertoire. With this study we aim to show the use of Remote Sensing in the field of vegetation recovery monitoring in burned areas and the added value of data with a high spatial resolution. This was done by analysing both Landsat 7 and 8 scenes, after the forest fire of summer 2012 in the parish of Calde, in the central region of Portugal, as well as an orthophoto produced with images acquired by an unmanned aerial vehicle.
A Deteção Remota tem sido utilizada durante décadas com novas aplicações a surgirem constantemente. Com este estudo pretende-se demonstrar o uso da Deteção Remota no campo da monotorização da recuperação de vegetação em áreas ardidas e o valor acrescentado da elevada resolução espacial dos dados utilizados. Para o efeito, foi feita a análise de áreas ardidas na freguesia de Calde, região central de Portugal, depois do incêndio florestal no verão de 2012, usando imagens Landsat 7 e 8 assim como uma ortofoto produzida com imagens adquiridas por um veículo aéreo não tripulado.

Between October 9, 1991 and October 16, 1991 a fire burned 577 hectares in the Columbia River Gorge near the west end on the Oregon side. All of the area burned consisted of second growth Pseudotsuga menziesii and the accompanying understory. This was the first disturbance of this magnitude in this part of the Columbia River Gorge since 1902. The purpose of this study was to examine the pattern of understory recovery in the first two years following the fire. This study also sought to learn: 1) how Pseudotsuga menziesii seedlings are recruited into the population, 2) how quickly the litter layer is a reforming, and 3) how quickly snags and downed logs are recruited into the understory. Four 800 square meter circular plots were established within the burned area of the Columbia River Gorge. Two plots were designated sun plots since the fire had killed the overstory. The other two were designated shade sites since the canopy over them was still intact. Twenty five randomly placed sample units (20 x 50 centimeters) were placed in each main plot. The plots were then sampled at approximately onemonth intervals from May through September of 1992 and 1993. The frequency and percentage of cover was recorded for all plant species that occurred in each sample unit. The data from 1992 and 1993 were compared by date of visit and type of plot, either (sun or shade) using the Pearson Goodness-of-Fit Test to examine and compare differences in the extent of cover and distribution of understory species. No significant differences were found. An increase in species richness and relative abundance of understory species was noted between pre-fire data collected by the US Forest Service and what I found. However, statistical analysis was not possible because of the limited data collection in the pre-fire sample.

Single-frequency and mode-locked silver film ion-exchanged glass waveguide lasers as well as all-optical clock recovery based on birefringent fiber resonators have been experimentally and theoretically studied. The theory, modeling and fabrication process of silver film ion-exchange techniques, have been discussed and presented.The UV-written gratings on both IOG-1 active and passive glass have been studied. For the first time, with a high quality narrowband grating UV-printed on the passive section of a hybrid glass, a DBR waveguide single-frequency laser is demonstrated with the linewidth less than 1 MHz and the output power of 9 mW.Novel saturable absorbers based on a fiber taper embedded in carbon nanotubes (CNTs)/polymer composite were demonstrated. The saturable absorbers were utilized to build mode-locked fiber lasers, which were studied experimentally. A mode-locked ring laser utilizing an Er-Yb-codoped glass waveguide as the gain medium was also demonstrated. In addition, short cavity mode-locked waveguide lasers with CNTs film on the top were theoretically investigated, which shows a short cavity mode-locked waveguide laser is very promising.A new concept to perform multi-channel multi-rate all-optical clock recovery based on birefringent fiber-optic waveguide resonators was discussed. The concept has been advanced to polarization-insensitive operation. The experimental results, obtained as a proof-of-concept, agree well with numerical simulations.

Coastal sage scrub (CSS), a lowland plant community native to California, is home to many rare, threatened, or endangered plants and animals. Fire, a natural feature of CSS, is essential for maintaining species diversity. However, the invasion of non-native grasses has altered the fire regime in CSS, increasing fire frequency and fire season length and decreasing fire intensity. Changes in the historical fire regime may in turn cause feedbacks that favor non-native species, resulting in the loss of biodiversity in invaded CSS sites. Numerous studies have examined patterns of post-fire succession in CSS; however, the role that the pre-fire seed bank and the relative abundance of natives to non-natives play in vegetation regrowth and community recovery is unclear. A lack of adequate pre-fire data on community composition makes testing hypotheses about the role of seed banks in post-fire recovery challenging. I propose to study recovery of the plant community in two differentially invaded CSS sites (East and West field) following a fire at the Bernard Field Station in September 2013. Data collected at the two sites from 2009-2013 reveal that non-native grass cover was significantly higher than native cover at both sites, though the West field had slightly higher native forb cover. Furthermore, the invasive grass Bromus diandrus almost entirely dominated the East field. Vegetation cover in the West field was more diverse with the abundance of other non-natives (Bromus hordeaceus, Bromus madritensis, Vulpia myuros) and natives (Amsinckia menziesii, Lupinus spp.) significantly higher than in the East field. To determine the effects of these pre-fire differences on recovery processes, I will carry out a randomized block experiment with four treatments (control, native seed addition, non-native grass removal, and both native seed addition and removal of non-native grasses). Twelve blocks will be evenly divided between the East and West fields. I propose to measure relative seedling abundance for both native and non-native species after each significant rainstorm over a three-year study period. I hypothesize that the composition of seed banks pre-fire will predict vegetation regrowth post-fire. Specifically, I predict that, under control conditions, B. diandrus will dominate the East field post-fire given its high abundance pre-fire. Further, I predict that regrowth in controls plots in the West field will be more variable given its more diverse seed bank pre-fire. Lastly, I predict that native forbs will exhibit the greatest degree of recovery in plots where active restoration methods (seeding and non-native grass removal) are employed; the effects of these restoration methods should be strongest in the East field because the pre-fire vegetation community was more heavily weighed towards non-native species. This study will add crucial knowledge to our understanding of how the pre-fire seed bank in CSS affects its recovery post-fire, which may inform future conservation efforts to ensure the continued health and protection of CSS sites around California.

Thesis (M.S.)--East Tennessee State University, 2003.
Title from electronic submission form. ETSU ETD database URN: etd-0411103-140848. Includes bibliographical references. Also available via Internet at the UMI web site.

Forest fires can have a great impact on the relationship between soil organic matter (SOM) and soilbulk density (SBD). SOM will reduce with increased fire intensity, which ultimately leads to more compaction of the soil. The compaction rate might increase to the limit of where root growth will be absent thus leading to actions to restore the soil. This study investigates changes in the relationship between SOM and SBD in spodosol and histosol in Seglingsberg, located in South-central Sweden, where a forest fire occurred summer 2014.  In addition, changes of pH values in the two types of soilwere examined in order to receive information about the chemical states of the different soil types.A total of 29 samples at depths of 0-17 cm were received from one day of fieldwork and these were later analysed concerning the pH, the SBD and the SOM content. The results showed an increase of pH-values in the fire-exposed area compared to pH values measured at the reference site (pH ~5). More importantly, the results from the SBD and SOM analyses indicated that there was in fact an inversely proportional relationship between the two soil parameters. In addition, high pH values were measured at the same subareas of which the highest SBD- and the lowest SOM values were obtained.Statistical analyses were applied on the results in order to conclude if the soil property changes caused by the fire were significantly different from normal conditions or not. The results from the statistical analyses revealed that 25% of the fire-exposed sites had changed significantly. However, more samples should have been taken while in field, since lack of data is thought to have had a great impact on the final results.Although there were no strong statistical evidence for the hypothesis, it is clear that the forest firein Västmanland year 2014 affected both the SOM, SBD and pH values in the soils.
Under sommaren år 2014 utbröt en omfattande skogsbrand i Västmanlands län, vilket medföljdedramatiska konsekvenser för framförallt ett flertal skogsbolag, men även för boende i området. Med skogsbränder följer negativa såväl som positiva konsekvenser, där de positiva framförallt gäller med avseende på arter som har evolverat i samband med bränder. Förutom ovannämnda konsekvenser så finns det risk för att markförhållandena ändras till följd av en skogsbrand. I denna studie undersöktes hur  markegenskaper  i  torv-  samt  podsoljordar  hade  förändrats  med  avseende  på  pH,  halten  avorganiskt material samt packningsgrad. Fältstudien genomfördes i ett drabbat brandområde strax norrom Seglingsberg, Surahammars kommun. Totalt togs 29 stycken jordprover inom fem stycken transekter i området. Av dessa kunde 25 stycken användas till alla tre analyserna. Resultaten från jordprovsanalyserna användes därefter till att genomföra statistiska undersökningar. Detta för att se hur stor spridningen var mellan och inom de fem transekterna samt för att kunna avgöra om jordproverna visade sig vara signifikant förändrade från ursprungsförhållanden.Resultaten från jordprovsanalyserna visade att det fanns mest organiskt material kvar i de östra delarna av området, medan det var kraftigt reducerat ju längre nordväst jordproverna hade hämtats. I samband med att markens organiska material hade reducerats kunde man även bevittna att jordtäcket hade blivit mer kompakterat. Resultaten från pH-analysen pekar också på att förändringarna varit som störst i de nordvästliga delarna. pH-analysen bevisade att markkemin ser annorlunda ut än innanbranden, då värdena ibland låg 2 enheter för högt än vad man vanligen brukar observera i podsol- ochtorvjordar. Då pH-skalan är logaritmisk innebär detta en minskad försurning med 100 gånger. Resultaten från alla jordprovsanalyser tyder att branden varit som mest intensiv i den nordvästra delen av undersökningsområdet, i området bestående av ungskog.Även om resultaten från jordprovsanalyserna pekade på att branden orsakat tydliga mark- förändringar, visade majoriteten av de statistiska undersökningarna inte på signifikanta förändringar. Det är därför inte möjligt att generalisera resultaten och således applicera dessa på hela brandområdet i Västmanland.Eftersom att naturligt förekommande skogsbränder är relativt få till antalet i Sverige, finns därmed få studier tillgängliga inom ämnesområdet. Det finns en upplaga av studier inom kontrollerade och anlagda brandfält, men i och med att dessa förhållanden är fixerade, så påverkas markegenskaperna sällan avsevärt. Forskningsrapporter indikerar på ett mer extremt klimat i framtiden, som förmodas leda till en ökad omfattning samt ett ökat antal naturligt förekommande skogsbränder. Om denna prognos stämmer är det viktigt att undersöka markförhållandena, då en skogsbrand kan ha direktavgörande effekt på återväxten.

Modern chemical technology is an efficient tool for solving problems, particularly within the complex environment of the pulp and paper industry, and the combination of experimental studies, mill data and mass balance calculations are of fundamental importance to the development of the industry. In this study various examples are presented, whereby chemical technology is of fundamental importance. It is well documented that under normal conditions the molten salt mixture from the kraft recovery boiler flows down into the dissolving tank without problems. However, in the case of  alternatives to the kraft recovery boiler, knowledge of more precise data of the molten salts is required for the design calculations. In this study the viscosity for the case of sodium carbonate and 30 mole% sulphide has been measured and is of the magnitude 2 – 3 cP at temperatures relevant for a recovery boiler, i.e. similar to water at room temperature. The presence of non-process elements (NPE) in a typical pulp mill has been investigated. The main input is with regards to the wood, and anticipated problems include; deposits in evaporators, high dead-load in liquor streams, plugging of the upper part of the recovery boiler and decreasing efficiency in the causticization department. Efficient green liquor clarification is of the greatest importance as an efficient kidney for many NPE. Mill data and calculations show that the magnesium added in the oxygen delignification does not form a closed loop. Integration of a prehydrolysis kraft pulp mill producing dissolving pulp with a plant producing viscose textile fiber could be highly beneficial. The prehydrolysis liquor will contain both sugars and acetic acid. It is however not possible to fully replace the sulphuric acid of the viscose spinning bath with acetic acid of own production. The sulphuric chemicals from the viscose plant can be partly taken care of in the kraft recovery area as well as the viscose plant which can be supplied with alkali and sulphuric acid. Zinc-containing effluents from the viscose plant can be treated with green liquor to precipitate zinc sulphide.
Modern chemical technology is an extremely efficient tool for solving problems particularly in a complicated environment such as the pulp and paper industry. Here, examples are studied during which chemical technology is of fundamental importance. At normal conditions the molten salt mixture from the kraft recovery boiler flows down into the dissolving tank without hindrance. However, for certain kraft recovery boiler alternatives, knowledge of more precise data of the molten salts is required. The viscosity for the case of sodium carbonate and 30 mole% sulphide has been measured and is of the magnitude 2 – 3 cP at relevant temperatures. The main input of non-process elements (NPE) is down to the wood, and known problems include deposits in evaporators and decreasing efficiency in the causticization department. Green liquor clarification is an efficient kidney for many NPE. Magnesium added in the oxygen delignification does not form a closed loop. Integration of a prehydrolysis kraft pulp mill producing dissolving pulp with a plant producing viscose textile fiber could be of significant interest, as the handling of both alkali and sulphuric compounds can be integrated. Problems will however arise as the capacity of the pulping line and the chemical recovery has to be adjusted.

Through research, inquiry, and an evaluation of Recovery By Design, a ‘design therapy’ program that serves people with mental illness, substance use disorders, and developmental disabilities, it is my assertion that the practice of design has therapeutic potential and can aid in the process of recovery. To the novice, the practices of conception, shaping form, and praxis have empowering benefit especially when guided by Conditional and Transformation Design methods together with an emphasis on materiality and vernacular form.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
A busca de modelos de desenvolvimento que minimizem ao máximo o impacto sobre o ambiente em que vivemos é o ideal a ser alcançado. Os benefícios proporcionados através dos objetos construídos pelo homem neste ambiente são reflexos de uma interferência adequada ao espaço habitado. Neste trabalho esta interferência é produzida pelas construções habitacionais. No bairro do Monteiro, área rural do município de Itamonte-MG, notou-se um processo de deterioração e empobrecimento dos conhecimentos construtivos tradicionais, inclusive a taipa. Apesar da eficiência destas construções, observou-se a gradativa degradação de alguns modos construtivos tradicionais no local. Os conhecimentos originais, de manejo de materiais adequado ao clima e local, foram abandonados e esquecidos. O trabalho de pesquisa que se apresenta aqui tem como objetivo fazer das técnicas construtivas consagradas, e que se utilizam de solo cru, um objeto de estudo a fim de resgatar conhecimentos e procedimentos, aperfeiçoá-los, adaptá-los a determinado local e mantê-los em desenvolvimento. A aplicação da metodologia do Laboratório de Investigação em Living Design ( LILD), será a base de sustentação dos experimentos que se realizarão ao longo do trabalho. Resumidamente esta metodologia propõe primeiramente após um estudo das características do contexto local, experimentos iniciais e empíricos, em campo e em laboratório, tendo sempre a participação e atuação dos membros da comunidade. A investigação tem prosseguimento com ensaios científicos, que permitem o controle e o aperfeiçoamento nos procedimentos utilizados em tais técnicas. Posteriormente a estas etapas aplicam-se novamente outros experimentos práticos no campo e novamente com participação da comunidade. Do compartilhamento das atividades do pesquisador e dos obreiros locais, resultou uma troca de informações que permitiu a aplicação do aprendizado da produção e da pesquisa num mesmo objeto. Aparecem com destaque no percurso do trabalho, experimentos que demonstraram a importância da utilização das fibras, não somente como agente estabilizador do solo, mas permitindo sim, novas possibilidades de vedações leves, principalmente como elemento definidor de compósitos em forma de lâminas e cascas.
Our goal is the search for development models that minimize environment impact. The benefits deriving from mans constructed objects on these environments reflect an adequate interference to the inhabited space. The resulting interference from habitation constructions is described. A process of deterioration and impoverishment of traditional constructive knowledge, including mud wall, was detected in the rural area of Monteiro, district of Itamonte in Minas Gerais, Brazil. In spite of the efficiency of these types of construction, the gradual degradation of some of the traditional constructive modes was verified. The original knowledge concerning the adequacy of materials to the climate and locality was abandoned and forgotten. The present research aims at studying the known constructive techniques, which use raw soil in order to recover their knowledge and procedures, to improve and adapt them to a certain place, and keep their development. The methodology of the Laboratory of Investigation in Living Design - LILD supports the experiments done along the work. In a few words, the methodology proposes a context study of local characteristics performing initial empiric experiments. This work is carried out at Monteiro and in the laboratory, always counting on the participation of community members. The investigation follows with scientific tests that allow for the control and improvement of procedures adopted in the studied techniques. The next step is to go back to the rural area and make other practical experiments, again, with the participation of community members. The result of shared activities between the researcher and local workers was the exchange of information concerning the production and the research itself, which allowed for the application of learned knowledge in the same object. Experiments along the way demonstrate the importance of utilizing fibers, not only as agents to stabilize soil, but also allowing for new light sealing possibilities, especially as main elements of composites in the form of plates and barks.

Objectives: The objectives of this study were to establish the extent of dermal and respiratory exposure at selected locations at a South African platinum mine. The study included exposure to lead oxide fumes in an assay laboratory, nickel sulfate powder at a nickel sulfate crystallizer circuit and packing site and metallic copper dust whilst executing copper stripping. Methods: In an availability study, the dermal metal exposures were measured before, during and at the end of shifts. Dermal exposure samples were taken with GhostwipesTM from the dominant hand, wrist and forehead. Wipes were analyzed using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). Wipe samples were taken from surfaces in the workplace and analyzed according to NIOSH 9102, using ICP-AES. Personal and static inhalable dust samples were taken and the dust samples were analyzed according to NIOSH 7300, using ICP-AES. A validated questionnaire was used to evaluate self reported dermatological complaints of the workers at the fire assay laboratory and base metal recovery plant. Results: 100% of the nickel respiratory exposures and 36.8% of the lead respiratory exposures were above the occupational exposure limits (OEL). Copper respiratory exposure was present but less significant with a geometric mean of 0.071 mg m-3. All of the dermal lead measurements and the majority of the nickel and copper dermal measurements were below the limit of detection. Nickel surface contamination was the most significant and ranged between 8.430 μg cm-2 and 387.488 μg cm-2. Only 30% of the copper surface sample results were below the detection limit with a maximum surface sample of 14.41 μg cm-2. Lead surface contamination was low with 90% of the samples below the limit of detection. All of the workers at the nickel crystallizer circuit and packing site had a Dalgard score above 1.3 and therefore are at a higher risk of developing a skin disease. None of the workers at the copper stripping site had a significant Dalgard score and only one worker at the fire assay laboratory had a score above 1.3 and therefore is at a higher risk of developing a skin disease. Conclusions: Recommendations were made to lower the exposure to inhalable lead and nickel. The low lead dermal measurements may be due to adequate personal protective equipment usage and hygiene practices. Although the ethnicity of the workers may be the reason for the low incidence of dermatological complaints, the Dalgard score indicated that five workers are at risk of developing skin diseases.
Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011

Les papiers récupérés sont de plus en plus utilisés pour fabriquer du papier recyclé de haute blancheur. La ligne de recyclage inclut entre autres les opérations de désencrage et de blanchiment, le peroxyde d’hydrogène (H2O2) étant le réactif blanchissant le plus utilisé en milieu alcalin (stade P). Son efficacité est toutefois limitée car il est peu ou moyennement réactif sur les fonctions azoïques des colorants papetiers. L’objectif de cette étude était donc d’améliorer l’élimination des colorants azoïques lors d’un stade P.L'amélioration du stade P utilisé en délignification des pâtes chimiques a fait l’objet de nombreuses études. En particulier, l’activation ou la catalyse de H2O2 par des complexes cuivre(II)-phénanthroline (Cu-Phen) présentant des résultats très intéressants, des essais de blanchiment de pâtes désencrées et colorées ont été entrepris. Le système H2O2/Cu-Phen s’est également révélé efficace en décoloration, mais le mécanisme n’avait alors pas été étudié.L’objectif de ce travail était donc de déterminer dans quel cas et pourquoi le complexe cuivre(II)-phénanthroline était capable d’améliorer la décoloration de fibres cellulosiques colorées. Trois questions intermédiaires se sont posées : (1) quel effet Cu-Phen a-t-il sur le colorant isolé? (2) la décoloration d’une pâte de fibres colorées par H2O2 est-elle améliorée par Cu-Phen? (3) par quel mécanisme la décoloration est-elle rendue plus efficace?Le travail a donc été organisé en trois études : (1) caractérisation des colorants sélectionnés et du complexe en l’absence d’oxydant et examen des interactions entre les deux, (2) étude et optimisation paramétrique de H2O2/Cu-Phen pour la décoloration de pâtes colorées, (3) étude du mécanisme d’oxydation en milieu aqueux, en l’absence et en présence de cellulose.Ce travail s’est appuyé sur de nombreuses techniques analytiques (spectroscopies RMN, FTIR, UV-vis et RPE ; ESI-MS) et des calculs de spéciation. Il a prouvé que le complexe Cu-Phen en présence de H2O2 améliorait la décoloration de colorants azoïques, avec ou sans fibres cellulosiques. Il a été mis en évidence que la phénanthroline agissait comme un stabilisant permettant d’ajuster la solubilité, la stabilité et le potentiel d’oxydo-réduction du cuivre(II), mais qu’elle n’était pas indispensable. De plus, le pH du milieu est également un paramètre clé, jouant à la fois sur l’activité du complexe et sur ses interactions avec le substrat. Le substrat (colorant mais aussi cellulose) s’est trouvé fortement dégradé par ce système H2O2/Cu-Phen. Les résultats corroborent l’hypothèse de l’oxydation du substrat par les radicaux hydroxyles issus de la décomposition de H2O2, plutôt que par H2O2 lui-même, ce mécanisme étant l’une des étapes d’un cycle catalytique.La recherche menée et les résultats obtenus sont applicables non seulement à l’amélioration du blanchiment des pâtes désencrées, mais aussi au traitement d’effluents colorés dans les industries du papier et du textile
Today, recovered papers are reused for the manufacture of bright paper after deinking and fiber bleaching, which generally starts with an alkaline hydrogen peroxide stage (H2O2). However, the efficiency of H2O2 is often limited due to its low reactivity on the azo groups of paper dyes contained in recovered papers. The goal of this study was to improve the removal of these azo dyes by H2O2.The improvement of H2O2 bleaching has been studied thoroughly in the context of chemical pulp delignification. In particular, the activation or catalysis of H2O2 by copper(II)-phenanthroline complexes (Cu-Phen) was found to be very effective. This inspired a preliminary bleaching study on deinked pulp and dyed pulp, and resulted in significant improvement of dye removal, which gave birth to our project.The purpose of this work was to determine to what extent copper(II)-phenanthroline could improve the hydrogen peroxide color-stripping of dyed cellulosic fibers, and how. To answer this question, three intermediate issues were addressed: (1) does Cu-Phen alone have an effect on the dye? (2) does Cu-Phen improve the color-stripping of a dyed pulp by H2O2? (3) how does the H2O2/Cu-Phen system enhance the dye-color-stripping efficiency?This work was thus divided into three studies: (1) the selected dyes and the complex were characterized in the absence of any oxidant and the interactions between the two were examined, (2) the H2O2/Cu-Phen system was applied on two dyed pulps to assess their color-stripping potential and to attempt to optimize it, and (3) the oxidation mechanism was investigated via trials in aqueous solution, with and without cellulose.Using several analytical techniques (NMR, FTIR, UV-vis and EPR spectroscopy; ESI-MS) and speciation calculations, this work proved that the Cu-Phen complex enhanced H2O2 for the color-stripping of azo dyes, with and without fibers. It also provided evidence that phenanthroline acted as a stabilizer to adjust the solubility, stability and redox potential of copper(II), but may not be indispensable. The substrate (dyes but also cellulose) was strongly degraded by the H2O2/Cu-Phen system. The results of the mechanistic study supported the hypothesis of substrate oxidation by radicals produced via decomposition of H2O2 rather than by hydrogen peroxide itself. This mechanism, strongly dependent on the pH, is probably part of a catalytic cycle.Finally, along with further research proposed based on our conclusions, this thesis should contribute to the improvement of deinked pulp bleaching as well as wastewater treatment in the pulp and textile industries

Shifting climate patterns are a cause for concern for natural ecosystems globally. Of particular concern is the effect of climate change on fire-prone, Mediterranean-type shrublands globally because of the heightened sensitivity of post-fire vegetation to environmental conditions. In this thesis, I focused on investigating the relationships between rainfall seasonality patterns and post-fire vegetation processes in neighbouring Fynbos and Renosterveld shrubland communities within the mega-diverse Cape Floristic Region of South Africa. I investigated vegetation sensitivity to moisture availability at multiple levels of detail including 1) productivity and community structure, 2) growth form responses and 3) physiological performance over three years. Post-fire rainfall patterns were manipulated by artificially increasing summer rainfall and reducing winter rainfall over permanent, field sites, thus reducing annual seasonality and creating soil moisture contrasts between control and treatment plots over warm and cool seasonal periods. At all levels of investigation, postfire vegetation processes at the Fynbos site were relatively insensitive to variations in moisture availability relative to the Renosterveld site where vegetation processes and community structure were strongly affected. Nutrient limitation and lower soil tension in coarse, sandstone-derived soils of the Fynbos site could strongly limit the influence of soil moisture patterns on post-fire physiology leading to stable growth, community structure and productivity under a variety of moisture regimes. Soil moisture patterns during the first summer had significant and long-term implications for community structure and productivity patterns in the Renosterveld site, highlighting the sensitivity of vegetation patterns to early post-fire processes. Overall this study demonstrates that post-fire rainfall patterns can have strong effects on vegetation recovery processes but that structurally similar shrublands, which are specialised to differing soil types, could show marked differences in their response to climate change due to the mediation of climate responses by soils.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: The present global biodiversity crisis is characterized mostly by loss of species due to habitat destruction but there other major threats – notably invasive alien species. The term “biodiversity hotspot” has been coined to emphasize areas for conservation prioritization – areas that have high biodiversity under threat from habitat destruction, invasive species, etc. The Cape Floristic Region (CFR) in the Western Cape (WC) Province of South Africa has the highest biodiversity of all Mediterranean-type climate regions globally and is classified among global biodiversity hotspots. The CFR, a Mediterranean-type climate heathland with a naturally high fire frequency, faces threat from transformation by development, disturbed (increased) fire frequencies and intensities, and invasive organisms, most notably invasive trees. Such threats disturb keystone species and keystone processes including insect pollinator assemblages and associated insect flower visitation webs and frequencies. Invasive pines are a serious threat to insect flower visitation as pine trees (Pinus spp.) shade out much indigenous vegetation in the CFR. Little is known of their long-term effects on insect flower visitors and vegetation recovery in post-pine restoration and recovery areas after such trees are removed. I investigated the recovery of vegetation and the most important insect pollinator, bees, after the removal of pines by fire and passive recovery in a CFR valley in the Western Cape. In 1999, a wildfire burned much of the WC Limietberg Nature Reserve along with an adjacent pine tree forestry stand - which was then left to recover, providing an ideal opportunity to investigate the enduring effects of pine afforestation in the CFR. In two data chapters, I compared the post-fire passive recovery of vegetation (Chapter 2) and bee diversity (Chapter 4) in areas which had previously been planted with pines vs. those which had contained natural fynbos. To improve on sampling methodology, I conducted an experiment that demonstrated the Observer Effect in bee sampling with a sweep net (Chapter 3), and I developed a novel sampling device (Chapter 5) for insect flower visitors. Sampling of vegetation and bee diversity was conducted in a paired sampling design, where fynbos (Natural) sub-sites were paired with sub-sites which had previously been afforested with pines (Post-Pine Recovery; PPR) and the two sub-sites were separated by a distinct, linear boundary (Natural/PPR boundary). Sampling was conducted along transects parallel to the boundary and extending in both directions from the boundary into the Natural and in the opposite direction into PPR sub-sites. Five transects were positioned at 3, 10, 20, 30, and 40 m from the boundary (Ecotone) and three were positioned at 60, 80, and 100 m from the boundary (Deep). In Chapter 2, I found that natural sub-sites consistently had higher total plant species abundance and species richness than PPR sub-sites. Approximately two thirds of plant species were more abundant in Natural sub-sites than in PPR sub-sites. There was no significant correlation in species richness or abundance with distance from the Natural/PPR boundary. Some genera are cautiously indicated as having lower success in recovery after pine afforestation: Erica spp., Restio spp., Hypodiscus spp. while Helichrysum spp. is also tentatively indicated to recover well in PPR sub-sites. Soil disturbance and concomitant disruption of normal ecosystem functions, including pollination, is indicated as a probable reason for disruption of plant recovery. In Chapter 3, sweep netting methodology was tested for the Observer Effect. A noticeable increase in bee visitation frequency to a common generalist plant species in bloom, Metalasia densa, was correlated with longer waiting periods after I stopped moving indicating the presence of an Observer Effect. This suggests that sweep netting for bees should only be commenced after a waiting period of five minutes during which the sweep netter is motionless. In Chapter 4, using a flight-intercept modified pan trap, I compared bee species richness and bee species abundance across different seasons and in both mass-flowering and sparser flower patches. There was no significant difference in bee species richness between Natural and PPR sub-sites. All bee species, except one complex, were more abundant in Natural sub-sites. Nearly two thirds of all bee species (n=37 of 56) caught with sweep netting and the modified pan trap are undescribed species. Similar to the vegetation, the effects of soil disturbance as a result of decades of pine forest shading and pine forest litterfall followed by an unusually hot pine forest fire are indicated as the most likely reasons for lower bee abundance in PPR sub-sites. This is due to the difficulty associated with viable nest establishment and suitable pollen and nectar forage availability in disturbed areas. In Chapter 5, the newly developed Pan and Flight Intercept Combination (PAFIC) trap’s design, pilot testing, and comparison with the traditional pan trap is discussed. A preliminary test suggests that the PAFIC trap is more efficient (with higher abundance) than the traditional pan trap. In Chapter 6, I discuss the implications of the disturbance of pine forestry and unusual pine fire to plant species and bee species assemblages. Bee-pollination webs in PPR sub-sites are indicated as being substantially simpler than those in Natural areas as well as compositionally different. The recovery of pollination as a keystone process in post pine-afforestation areas faces a substantial challenge given the disturbance to soil that decades of pine afforestation followed by pine forest fire can cause. Some suggestions are made for the restoration of fynbos areas recovering from pine afforestation including a discussion of augmenting re-vegetation measures (fynbos seed dispersal and seedling planting) with methods of restoring of healthy pedogenesis, epigaeic arthropod communities, and fynbos seedbanks.
AFRIKAANSE OPSOMMING: Die huidige globale biodiversiteit krisis is gekenmerk meestal deur die verlies van spesies as gevolg van die vernietiging van habitat. Maar daar is ook ander groot bedreigings – veral merkbaar indringerspesies. Die term “biodiversiteit brandpunt” is geskep om gebiede vir bewaring prioritisering te beklemtoon - gebiede wat 'n hoë biodiversiteit bevat wat bedreig word deur die vernietiging van habitat, indringerspesies, ens. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap (WK) Provinsie van Suid-Afrika het die hoogste biodiversiteit van alle Mediterreense tipe klimaat streke wêreldwyd, en is onder die globale biodiversiteit brandpunte geklassifiseer. Die KFS, 'n Mediterreense-tipe klimaat heideveld met 'n natuurlike hoë brand frekwensie, word bedreig as gevolg van transformasie deur ontwikkeling, versteurde (verhoogde) vuur regimes, en indringer organismes, veral indringerbome. Sulke bedreigings versteur hoeksteen spesies en die hoeksteen prosesse, insluitende insek bestuiwer samestelling en verwante insek blom besoekings webbe en frekwensies. Indringer dennebome (Pinus spp.) is 'n ernstige bedreiging vir insek blom besoeking want dennebome verskaf skaduwee aan baie inheemse plantegroei in die KFS. Min is bekend oor die langtermyn effekte op insek blom besoekers en plantegroei restorasie na denneboom verwydering en restorasie gebiede na sodanige bome verwyder word. Ek ondersoek die restorasie van plantegroei en die belangrikste insek bestuiwer, bye, na die vernietiging van dennebome deur vuur en passiewe herstel in 'n KFS vallei in die Wes-Kaap. In 1999 het'n veldbrand baie van die WK Limietberg Natuurreservaat saam met 'n aangrensende denneboom bosbouplantasie gebrand - wat toe gelaat is om te herstel via intermediêre suksessie na inheemse fynbos plantegroei. Dit bied 'n ideale geleentheid om die blywende gevolge van denneboom aanplanting in die KFS te ondersoek. In twee data hoofstukke, vergelyk ek die passiewe herstel van plantegroei na ‘n brand (Hoofstuk 2) en by diversiteit (Hoofstuk 4) in gebiede wat voorheen geplant is met dennebome teenoor diegene wat natuurlike fynbos vervat het. Om te verbeter op steekproefmetodiek, het ek 'n eksperiment onderneem wat demonstreer hoe die Waarnemer Effek by monsterneming met 'n vee-net beïnvloed (Hoofstuk 3), en het ek 'n nuwe monsterneming toestel ontwerp (Hoofstuk 5) vir insek blom besoekers. Monsterneming van plantegroei en by diversiteit is uitgevoer in 'n gegroepeerde steekproef ontwerp, waar fynbos (Natuurlik) sub-terreine gegroepeer is met sub-terreine wat voorheen aangeplant was met dennebome (Na Denneboom Verwydering Herstel; NDVH) en die twee sub-terreine is geskei deur 'n duidelike, lineêre grens (Natuurlik / NDVH grens). Steekproefneming is gedoen langs transekte parallel tot die grens en versprei in albei rigtings van die grens tot binne die natuurlike fynbos en in die teenoorgestelde rigting tot binne NDVH sub-terreine. Vyf transekte is geposisioneer binne 50 m van die grens (Oorgang sone) en drie is ver geplaas van die grens (Diep). In Hoofstuk 2 het ek gevind dat natuurlike sub-terreine konsekwent hoër totale getal plant individue en spesierykheid as NDVH sub-terreine gehad het. Ongeveer twee derdes van plantspesies was meer volop in natuurlike sub-terreine as in NDVH sub-terreine. Daar was geen beduidende korrelasie in spesierykheid of totale hoeveelheid plant individue met betrekking tot afstand van die Natuurlike /NDVH grens. Sommige genera word versigtig aangedui as met laer sukses in die restorasie terreine na denneboom aanplanting: Erica spp., Restio spp., Hypodiscus spp. terwyl Helichrysum spp. voorlopig aangedui is as goed herstel in NDVH sub-terreine. Grondversteuring en gepaardgaande ontwrigting van normale funksionering van die ekosisteem, insluitend bestuiwing, word aangedui as 'n waarskynlike rede vir die ontwrigting van die herstel van plantegroei. In Hoofstuk 3 is vee-net metodologie getoets vir die Waarnemer Effek. 'N merkbare toename in by besoeking frekwensie van 'n algemene plantspesie in blomtyd, Metalasia densa, is gekorreleer met langer wagtydperke nadat ek gestop het om te beweeg, en dui dus op die teenwoordigheid van 'n Waarnemer Effek. Dit dui daarop dat die vee-net vir bye eers gebruik moet word na 'n wagtydperk waartydens die waarnemer bewegingloos verkeer. In Hoofstuk 4, met behulp van 'n vlug-onderskep gewysigde pan lokval, het ek by spesierykheid en totale by hoeveelheid vergelyk oor verskillende seisoene en in beide massa-beblomde en yler blom kolle. Daar was geen beduidende verskil in by spesierykheid tussen natuurlike en NDVH sub-terreine. Alle by spesies, behalwe een spesie kompleks, was meer volop in natuurlike sub-terreine. Byna twee derdes van alle by spesies (n = 37 van 56) gevang met vee-nette en die van die gewysigde pan lokvalle is onbeskryfde spesies. Soortgelyk aan die plantegroei, is die gevolge van grondversteuring as gevolg van dekades van denneboom bos skadu en denneboom bos blaar afval gevolg deur 'n buitengewoon warm denneboom bos brand as die mees waarskynlike redes vir laer by hoeveelheid in NDVH sub-terreine aangedui. Dit is as gevolg van die probleme wat verband hou met lewensvatbare nes vestiging en geskikte stuifmeel en nektar voer beskikbaarheid in versteurde gebiede. In Hoofstuk 5 is die nuut ontwikkelde Pan en Vlug Onderskep Kombinasie (PEVOK) lokval ontwerp, aanvanklike toetsing, en vergelyking met die tradisionele pan lokval bespreek. 'N Voorlopige toets dui daarop dat die PEVOK lokval meer doeltreffend (met 'n hoër oorvloed) is as die tradisionele pan lokval. In Hoofstuk 6 bespreek ek die implikasies van die versteuring van denneboom bosbou en ongewone denneboom vuur met betrekking tot plant spesies en by spesies samestelling. By-bestuiwing webbe in NDVH sub-terreine word aangedui as wesenlik eenvoudiger as dié in natuurlike areas asook verskillend in samestelling. Die herstel van bestuiwing as 'n hoeksteen in na denneboom-aangeplante gebiede staar 'n aansienlike uitdaging in die gesig, gegee die versteuring van grond wat dekades van denneboom aanplanting gevolg deur denneboom bos brand kan veroorsaak. Sommige voorstelle is gemaak vir die herstel van fynbos gebiede wat herstel van denneboom aanplanting, insluitend 'n bespreking van die aanvulling van plantegroei hervestiging maatreëls (fynbos saadverspreiding en saailinge plant) met die metodes van die herstel van 'n gesonde pedogenese, bogrondse geleedpotige gemeenskappe, en fynbos saadbanke.