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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

The Spatial and Temporal Distribution of the Metal Mineralisation in Eastern Australia and the Relationship of the Observed Patterns to Giant Ore Deposits

Robinson, Larry J. Unknown Date (has links)
The introduced mineral deposit model (MDM) is the product of a trans-disciplinary study, based on Complexity and General Systems Theory. Both investigate the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. The focus of the research has been on giant, hydrothermal mineral deposits. They constitute <0.001% of the total number of deposits yet contain 70-85% of the world's metal resources. Giants are the definitive exploration targets. They are more profitable to exploit and less susceptible to fluctuations of the market. Consensus has it that the same processes that generate small deposits also form giants but those processes are simply longer, vaster, and larger. Heat is the dominant factor in the genesis of giant mineral deposits. A paleothermal map shows where the vast heat required to generate a giant has been concentrated in a large space, and even allows us to deduce the duration of the process. To generate a paleothermal map acceptable to the scientific community requires reproducibility. Experimentation with various approaches to pattern recognition of geochemical data showed that the AUTOCLUST algorithm not only gave reproducibility but also gave the most consistent, most meaningful results. It automatically extracts boundaries based on Voronoi and Delaunay tessellations. The user does not specify parameters; however, the modeller does have tools to explore the data. This approach is near ideal in that it removes much of the human-generated bias. This algorithm reveals the radial, spatial distribution, of gold deposits in the Lachlan Fold Belt of southeastern Australia at two distinct scales – repeating patterns every ~80 km and ~230 km. Both scales of patterning are reflected in the geology. The ~80 km patterns are nested within the ~230 km patterns revealing a self-similar, geometrical relationship. It is proposed that these patterns originate from Rayleigh-Bénard convection in the mantle. At the Rayleigh Number appropriate for the mantle, the stable planform is the spoke pattern, where hot mantle material is moving upward near the centre of the pattern and outward along the radial arms. Discontinuities in the mantle, Rayleigh-Bénard convection in the mantle, and the spatial distribution of giant mineral deposits, are correlative. The discontinuities in the Earth are acting as platforms from which Rayleigh-Bénard convection can originate. Shallow discontinuities give rise to plumelets, which manifest at the crust as repeating patterns ranging, from ~100 to ~1,000 km in diameter. Deeper discontinuities give rise to plumes, which become apparent at the crust as repeating patterns ranging from >1,000 to ~4,000 km in diameter. The deepest discontinuities give rise to the superplumes, which become detectable at the crust as repeating patterns ranging from >4,000 to >10,000 km in diameter. Rayleigh-Bénard convection concentrates the reservoir of heat in the mantle into specific locations in the crust; thereby providing the vast heat requirements for the processes that generate giant, hydrothermal mineral deposits. The radial spatial distribution patterns observed for gold deposits are also present for base metal deposits. At the supergiant Broken Hill deposit in far western New South Wales, Australia, the higher temperature Broken Hill-type deposits occur in a radial pattern while the lower temperature deposits occur in concentric patterns. The supergiant Broken Hill deposit occurs at the very centre of the pattern. If the supergiant Broken Hill Deposit was buried beneath alluvium, water or younger rocks, it would now be possible to predict its location with accuracy measured in tens of square kilometres. This predictive accuracy is desired by every exploration manager of every exploration company. The giant deposits at Broken Hill, Olympic Dam, and Mount Isa all occur on the edge of an annulus. There are at least two ways of creating an annulus on the Earth's surface. One is through Rayleigh-Bénard convection and the other is through meteor impact. It is likely that only 'large' meteors (those >10 km in diameter) would have any permanent impact on the mantle. Lesser meteors would leave only a superficial scar that would be eroded away. The permanent scars in the mantle act as ‘accidental templates’ consisting of concentric and possibly radial fractures that impose those structures on any rocks that were subsequently laid down or emplaced over the mantle. In southeastern Australia, the proposed Deniliquin Impact structure has been an 'accidental template' providing a 'line-of-least-resistance' for the ascent of the ~2,000 km diameter, offshore, Cape Howe Plume. The western and northwestern radial arms of this plume have created the very geometry of the Lachlan Fold Belt, as well as giving rise to the spatial distribution of the granitic rocks in that belt and ultimately to the gold deposits. The interplay between the templating of the mantle by meteor impacts and the ascent of plumelets, plumes or superplumes from various discontinuities in the mantle is quite possibly the reason that mineral deposits occur where they do.
472

The Spatial and Temporal Distribution of the Metal Mineralisation in Eastern Australia and the Relationship of the Observed Patterns to Giant Ore Deposits

Robinson, Larry J. Unknown Date (has links)
The introduced mineral deposit model (MDM) is the product of a trans-disciplinary study, based on Complexity and General Systems Theory. Both investigate the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. The focus of the research has been on giant, hydrothermal mineral deposits. They constitute <0.001% of the total number of deposits yet contain 70-85% of the world's metal resources. Giants are the definitive exploration targets. They are more profitable to exploit and less susceptible to fluctuations of the market. Consensus has it that the same processes that generate small deposits also form giants but those processes are simply longer, vaster, and larger. Heat is the dominant factor in the genesis of giant mineral deposits. A paleothermal map shows where the vast heat required to generate a giant has been concentrated in a large space, and even allows us to deduce the duration of the process. To generate a paleothermal map acceptable to the scientific community requires reproducibility. Experimentation with various approaches to pattern recognition of geochemical data showed that the AUTOCLUST algorithm not only gave reproducibility but also gave the most consistent, most meaningful results. It automatically extracts boundaries based on Voronoi and Delaunay tessellations. The user does not specify parameters; however, the modeller does have tools to explore the data. This approach is near ideal in that it removes much of the human-generated bias. This algorithm reveals the radial, spatial distribution, of gold deposits in the Lachlan Fold Belt of southeastern Australia at two distinct scales – repeating patterns every ~80 km and ~230 km. Both scales of patterning are reflected in the geology. The ~80 km patterns are nested within the ~230 km patterns revealing a self-similar, geometrical relationship. It is proposed that these patterns originate from Rayleigh-Bénard convection in the mantle. At the Rayleigh Number appropriate for the mantle, the stable planform is the spoke pattern, where hot mantle material is moving upward near the centre of the pattern and outward along the radial arms. Discontinuities in the mantle, Rayleigh-Bénard convection in the mantle, and the spatial distribution of giant mineral deposits, are correlative. The discontinuities in the Earth are acting as platforms from which Rayleigh-Bénard convection can originate. Shallow discontinuities give rise to plumelets, which manifest at the crust as repeating patterns ranging, from ~100 to ~1,000 km in diameter. Deeper discontinuities give rise to plumes, which become apparent at the crust as repeating patterns ranging from >1,000 to ~4,000 km in diameter. The deepest discontinuities give rise to the superplumes, which become detectable at the crust as repeating patterns ranging from >4,000 to >10,000 km in diameter. Rayleigh-Bénard convection concentrates the reservoir of heat in the mantle into specific locations in the crust; thereby providing the vast heat requirements for the processes that generate giant, hydrothermal mineral deposits. The radial spatial distribution patterns observed for gold deposits are also present for base metal deposits. At the supergiant Broken Hill deposit in far western New South Wales, Australia, the higher temperature Broken Hill-type deposits occur in a radial pattern while the lower temperature deposits occur in concentric patterns. The supergiant Broken Hill deposit occurs at the very centre of the pattern. If the supergiant Broken Hill Deposit was buried beneath alluvium, water or younger rocks, it would now be possible to predict its location with accuracy measured in tens of square kilometres. This predictive accuracy is desired by every exploration manager of every exploration company. The giant deposits at Broken Hill, Olympic Dam, and Mount Isa all occur on the edge of an annulus. There are at least two ways of creating an annulus on the Earth's surface. One is through Rayleigh-Bénard convection and the other is through meteor impact. It is likely that only 'large' meteors (those >10 km in diameter) would have any permanent impact on the mantle. Lesser meteors would leave only a superficial scar that would be eroded away. The permanent scars in the mantle act as ‘accidental templates’ consisting of concentric and possibly radial fractures that impose those structures on any rocks that were subsequently laid down or emplaced over the mantle. In southeastern Australia, the proposed Deniliquin Impact structure has been an 'accidental template' providing a 'line-of-least-resistance' for the ascent of the ~2,000 km diameter, offshore, Cape Howe Plume. The western and northwestern radial arms of this plume have created the very geometry of the Lachlan Fold Belt, as well as giving rise to the spatial distribution of the granitic rocks in that belt and ultimately to the gold deposits. The interplay between the templating of the mantle by meteor impacts and the ascent of plumelets, plumes or superplumes from various discontinuities in the mantle is quite possibly the reason that mineral deposits occur where they do.
473

The Spatial and Temporal Distribution of the Metal Mineralisation in Eastern Australia and the Relationship of the Observed Patterns to Giant Ore Deposits

Robinson, Larry J. Unknown Date (has links)
The introduced mineral deposit model (MDM) is the product of a trans-disciplinary study, based on Complexity and General Systems Theory. Both investigate the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. The focus of the research has been on giant, hydrothermal mineral deposits. They constitute <0.001% of the total number of deposits yet contain 70-85% of the world's metal resources. Giants are the definitive exploration targets. They are more profitable to exploit and less susceptible to fluctuations of the market. Consensus has it that the same processes that generate small deposits also form giants but those processes are simply longer, vaster, and larger. Heat is the dominant factor in the genesis of giant mineral deposits. A paleothermal map shows where the vast heat required to generate a giant has been concentrated in a large space, and even allows us to deduce the duration of the process. To generate a paleothermal map acceptable to the scientific community requires reproducibility. Experimentation with various approaches to pattern recognition of geochemical data showed that the AUTOCLUST algorithm not only gave reproducibility but also gave the most consistent, most meaningful results. It automatically extracts boundaries based on Voronoi and Delaunay tessellations. The user does not specify parameters; however, the modeller does have tools to explore the data. This approach is near ideal in that it removes much of the human-generated bias. This algorithm reveals the radial, spatial distribution, of gold deposits in the Lachlan Fold Belt of southeastern Australia at two distinct scales – repeating patterns every ~80 km and ~230 km. Both scales of patterning are reflected in the geology. The ~80 km patterns are nested within the ~230 km patterns revealing a self-similar, geometrical relationship. It is proposed that these patterns originate from Rayleigh-Bénard convection in the mantle. At the Rayleigh Number appropriate for the mantle, the stable planform is the spoke pattern, where hot mantle material is moving upward near the centre of the pattern and outward along the radial arms. Discontinuities in the mantle, Rayleigh-Bénard convection in the mantle, and the spatial distribution of giant mineral deposits, are correlative. The discontinuities in the Earth are acting as platforms from which Rayleigh-Bénard convection can originate. Shallow discontinuities give rise to plumelets, which manifest at the crust as repeating patterns ranging, from ~100 to ~1,000 km in diameter. Deeper discontinuities give rise to plumes, which become apparent at the crust as repeating patterns ranging from >1,000 to ~4,000 km in diameter. The deepest discontinuities give rise to the superplumes, which become detectable at the crust as repeating patterns ranging from >4,000 to >10,000 km in diameter. Rayleigh-Bénard convection concentrates the reservoir of heat in the mantle into specific locations in the crust; thereby providing the vast heat requirements for the processes that generate giant, hydrothermal mineral deposits. The radial spatial distribution patterns observed for gold deposits are also present for base metal deposits. At the supergiant Broken Hill deposit in far western New South Wales, Australia, the higher temperature Broken Hill-type deposits occur in a radial pattern while the lower temperature deposits occur in concentric patterns. The supergiant Broken Hill deposit occurs at the very centre of the pattern. If the supergiant Broken Hill Deposit was buried beneath alluvium, water or younger rocks, it would now be possible to predict its location with accuracy measured in tens of square kilometres. This predictive accuracy is desired by every exploration manager of every exploration company. The giant deposits at Broken Hill, Olympic Dam, and Mount Isa all occur on the edge of an annulus. There are at least two ways of creating an annulus on the Earth's surface. One is through Rayleigh-Bénard convection and the other is through meteor impact. It is likely that only 'large' meteors (those >10 km in diameter) would have any permanent impact on the mantle. Lesser meteors would leave only a superficial scar that would be eroded away. The permanent scars in the mantle act as ‘accidental templates’ consisting of concentric and possibly radial fractures that impose those structures on any rocks that were subsequently laid down or emplaced over the mantle. In southeastern Australia, the proposed Deniliquin Impact structure has been an 'accidental template' providing a 'line-of-least-resistance' for the ascent of the ~2,000 km diameter, offshore, Cape Howe Plume. The western and northwestern radial arms of this plume have created the very geometry of the Lachlan Fold Belt, as well as giving rise to the spatial distribution of the granitic rocks in that belt and ultimately to the gold deposits. The interplay between the templating of the mantle by meteor impacts and the ascent of plumelets, plumes or superplumes from various discontinuities in the mantle is quite possibly the reason that mineral deposits occur where they do.
474

Stretchable Magnetoelectronics / Dehnbare Magnetoelektronik

Melzer, Michael 22 December 2015 (has links) (PDF)
In this work, stretchable magnetic sensorics is successfully established by combining metallic thin films revealing a giant magnetoresistance effect with elastomeric materials. Stretchability of the magnetic nanomembranes is achieved by specific morphologic features (e.g. wrinkles), which accommodate the applied tensile deformation while maintaining the electrical and magnetic integrity of the sensor device. The entire development, from the demonstration of the world-wide first elastically stretchable magnetic sensor to the realization of a technology platform for robust, ready-to-use elastic magnetoelectronics with fully strain invariant properties, is described. The prepared soft giant magnetoresistive devices exhibit the same sensing performance as on conventional rigid supports, but can be stretched uniaxially or biaxially reaching strains of up to 270% and endure over 1,000 stretching cycles without fatigue. The comprehensive magnetoelectrical characterization upon tensile deformation is correlated with in-depth structural investigations of the sensor morphology transitions during stretching. With their unique mechanical properties, the elastic magnetoresistive sensor elements readily conform to ubiquitous objects of arbitrary shapes including the human skin. This feature leads electronic skin systems beyond imitating the characteristics of its natural archetype and extends their cognition to static and dynamic magnetic fields that by no means can be perceived by human beings naturally. Various application fields of stretchable magnetoelectronics are proposed and realized throughout this work. The developed sensor platform can equip soft electronic systems with navigation, orientation, motion tracking and touchless control capabilities. A variety of novel technologies, like smart textiles, soft robotics and actuators, active medical implants and soft consumer electronics will benefit from these new magnetic functionalities.
475

Assemblages végétaux pour phytomanager des sols contaminés en métaux (Cu et Zn/Pb/Cd), rhizofiltrer de l’eau contaminée en Cu et fournir des biomasses à la bioéconomie / Plant assemblages to phytomanage metal (Cu and Zn/Pb/Cd)-contaminated soils, rhizofiltrate Cu-contaminated water, and deliver usable biomass for the bioeconomy

Oustrière, Nadège 05 December 2016 (has links)
Le phytomanagement de matrices contaminées en métaux couple leur réhabilitation écologique avec la production de biomasses végétales pour la bioéconomie. Un front de science est d’identifier des assemblages végétaux et d’optimiser leur production, aidée ou non par l’ajout d’amendements. Le phytomanagement de deux sols, l’un contaminé en Cu, l’autre en Cd, Pb et Zn, a été testé en conditions contrôlées. L’emploi conjoint de biochar et de grenaille d’acier diminue la phytotoxicité des 2 sols. En pots, sur 2 ans, cette combinaison d’amendements séquestre du carbone, diminue la phytotoxicité du sol contaminé en Cu et produit une biomasse d’Arundo donax L. et de Populus nigra L. non contaminée, utilisable par le secteur de l’énergie. Ces modalités de culture et d’amendement ont été installées pour un suivi à long terme sur le site contaminé en Cu. Parallèlement, en microcosmes, parmi 4 macrophytes utilisées en zone humide construite (CW) pour décontaminer des matrices aqueuses (i.e. Arundo donax L., Cyperus eragrostis Lam., Iris pseudacorus L. et Phalaris arundinacea L.), A. donax est la mieux adaptée pour fournir des racines à forte concentration en Cu utilisables pour produire un écocatalyseur riche en Cu. Le phytomanagement d’un effluent de bouillie bordelaise (EB, 69 μM Cu) par A. donax a été testé en CW pilote. Il est décontaminé en 48h, sa concentration en Cu respectant la réglementation du rejet d’effluent en réseau d'assainissement. Cependant, après un cycle de circulation, la concentration en Cu des racines d’A. donax (623 ± 140 mg Cu kg-1) est inférieure aux besoins de l’éco-catalyse, et le cycle serait à répéter pour atteindre les 1000 mg Cu kg-1 requis. / The phytomanagement of metal-contaminated matrices (soils and water) combines their ecological remediation and the production of non-food crops for the bioeconomy. One science frontier is to identify plant assemblage and to optimize their biomass production, aided or not by amendment addition and cultural practices. A Cu-contaminated soil and a Cd/Pb/Zn-contaminated one were phytomanaged in controlled conditions. The combination of biochar and iron grit reduced the phytotoxicity in both soils. In a 2-year pot experiment, this amendment combination decreased the phytotoxicity of the Cu-contaminated soil, enhanced soil C sequestration and produced an uncontaminated biomass of Arundo donax L. and Populus nigra L. adapted for bioenergy production. These combinations of culture and amendment are tested in field trial at the Cu-contaminated site. In parallel, in microcosm experiment, out of 4 macrophytes commonly used in constructed wetlands (CW) to clean up aqueous matrices (i.e. Arundo donax L., Cyperus eragrostis Lam., Iris pseudacorus L. and Phalaris arundinacea L.), A. donax was the best adapted to produce a high Cu-rich root mat potentially usable as Cu-ecocatalyst. Clean up of a Bordeaux mixture effluent (BME, 69 μM Cu) by A. donax was tested in a pilot-scale CW. The BME was decontaminated in 48 hours, its Cu concentration being in compliance for indirect discharge of chemical industry effluents. However, after one BME circulation cycle, root Cu concentration of A. donax roots (623 ± 140 mg kg-1) was lower than threshold value for Cu-ecocatalysts (1000 mg kg-1) and successive treatments must be repeated to achieve required Cu concentration.
476

Investigation of membrane fusion as a function of lateral membrane tension / Investigation of membrane fusion as a function of lateral membrane tension

Kliesch, Torben-Tobias 07 June 2017 (has links)
No description available.
477

Beiträge zur Theorie des Supermagnetwiderstandes in magnetischen Vielfachschichten

Zahn, Peter 11 August 2021 (has links)
Es werden ab-initio Rechnungen des Supermagnetwiderstands-Effektes von Fe/Cr-Multilagen vorgestellt. Die Elektronenstruktur wurde im Rahmen einer LCAO-Superzellen-Rechnung bestimmt. Als Störung der idealen Schichtstruktur wurden Cr-Defekte in Fe angenommen, die durch spinabhängige Relaxationszeiten beschrieben werden. Die elektrischen Transportkoeffizienten wurden durch Lösung der linearisierten Boltzmann-Gleichung in Relaxationszeitnäherung unter Verwendung des Mott-schen Zweistrommodells berechnet. Bei den betrachteten Systemen variierte die Dicke der Fe-Schicht zwischen 3 und 9 Monolagen, die der Cr-Schicht zwischen 1 und 13 Monolagen. In Abhängigkeit von der Fe- bzw. Cr-Schichtdicke ergeben sich in Übereinstimmung mit den Experimenten charakteristische Oszillationen des Supermagnetwiderstandes. Es wird der Einfluß der Spinanisotropie der Streuung auf den Effekt untersucht. Insbesondere kann gezeigt werden, daß der Effekt auch für spinunabhängige Streuung existiert. / Ab-initio calculations of the Giant Magnetoresistance (GMR) for Fe/Cr multilayers are presented. The electronic structure of the Fe/Cr superlattice is calculated within an optimized LCAO scheme using the local spin density approximation. The scattering of the electrons by Cr impurities in an Fe environment is taken into account by spin dependent relaxation times. The transport is described quasiclassically by solving the linearized Boltzmann equation in relaxation time approximation. In agreement with experiments characteristic oscillations of the GMR are obtained in dependence on the Cr and Fe layer thickness. It can be shown, that the GMR can be reduced or increased by the spin anisotropy of the scattering, but the phenomenon still exists for spin-independent scattering.
478

Krystalochemie granátů pyralspitové skupiny / Crystal chemistry of pyralspite garnets

Soumar, Jan January 2011 (has links)
Bohemian garnets have been known as a jewellery stone for many centuries. There is still a lot of interest in them, however, the reserves in traditional locations are getting smaller. That is why search for alternative source of similar garnets in gem quality started. Shavaryn Tsaram deposit in Mongolia is considered as one of the potential sources. Pyrope samples from eight Bohemian localities of two areas (České středohoří [The Central Bohemian Uplands] and Podkrkonoší [The Giant Mountains]) and from Shavaryn Tsaram deposit in Mongolia were analysed using electron microprobe, LA-ICP-MS, ICP-OES, Mössbauer spectroscopy and x-ray powder diffraction. The data were compared with the conclusion that the Mongolian garnets from Shavaryn Tsaram deposit are so different from the Bohemian ones that it will not be possible to use them as a gem material of similar qualities. Bohemian garnet can be characterised as a red garnet with refraction index 1.747 (+/- 0.001) with dominant pyrope component of the average composition Py78Alm17Gr5 and Cr2O3 content above 1 wt.%. The data were also evaluated from two classification schemes point of view. The schemes by Schulze (2003) and Grütter (2004) are used in determining source materials and in diamond prospection. According to them source rocks of Bohemian garnets...
479

Blue Growth : Applications and properties of biochar made out of reed / Blå Tillväxt : Tillämpning och egenskaper hos biokol gjort på vass

Karlsson, Axel, Fagerström, Pinthira January 2021 (has links)
The climate on earth keeps getting warmer where heat waves, eutrophication, rising sea levels, extreme weather like flooding, droughts and wildfires are an expanding problem. The focus of this bachelor thesis is to determine the potential of mitigating eutrophication and while contributing to blue growth by harvesting and make use of reeds like Phragmites australis and Arundo donax. Reeds have the ability to quickly absorb nutrients from aquatic environments and there are opportunities to use them as a feedstock for producing biochar to be potentially used in areas such as soil improvement, fodder additive and carbon sequestration. Additionally, optimal biochar properties for the observed applications gets analysed. The thesis is based on a systematic literature review and an interview with Niclas Anvret at the non-profit organisation “Race for the Baltic”.  Results show that biochar produced according to parameters such as heating rate, biomass species and especially, different temperatures, results in varied characteristics that change the biochar's adsorption abilities, nutrient retention, alkalinity, stability, surface area and porosity volume. The different applications of biochar are, however, not easily determined. This is because of the fact that certain biochar properties, that are prominent in entirely different pyrolysis conditions, could both be beneficial for the same application. Additionally, the different attributes sometimes influence each other which gives rise to unclear patterns affecting use potential. To overcome these issues, more research is needed to clarify the correlations between attributes of the biochar and to determine which characteristics of biochar are best suited for each application.  In terms of how large-scale harvesting of reed could affect the ecosystem is also unclear, there is not enough research regarding the question to be able to draw clear conclusions. The reasoning behind this is that there are knowledge gaps, geographical differences, different unit measuring and methodology. The potential for biochar in the coal market is high and the demand in Sweden has risen over the past couple of years. There is also interest in using biochar as a soil amendment, to make use of nutrient content as well as applying organic matter to soils to potentially achieve long-term carbon sequestration. However, the production cost of biochar out of reed is relatively expensive, and it cannot compete with coal or other fertilisers/soil amendments on the market, with feedstock management usually being the most expensive part of production. Lastly, there is currently no harvesting method that can measure the amount of reed that needs to be harvested to be able to produce biochar on a large scale. / Klimatet på jorden blir allt varmare och värmeböljor, övergödning, stigande havsnivåer, extrema väder som översvämningar, torka och bränder är ett stigande problem. Syftet med denna kandidatuppsats är att undersöka potentialen att mildra eutrofiering och samtidigt bidra till blå tillväxt genom att skörda - och använda sig av vass som Phragmites australis och Arundo donax. Vass har en framträdande förmåga att absorbera näringsämnen. Det finns därför möjligheter att använda dem som råvara för att producera biokol som potentiellt kan användas i områden såsom jordförbättring, fodertillsatser och kolbindning. Utöver detta undersöks optimala egenskaper för biokol enligt de observerade applikationerna. Kandidatuppsatsen bygger på en systematisk litteraturstudie och en intervju med Niclas Anvret på den ideella organisationen ”Race for the Baltic”.  Resultaten indikerar att biokol, producerad i pyrolys enligt parametrar som uppvärmningshastighet, biomassa och i synnerhet olika temperaturer, resulterar i varierande egenskaper som förändrar biokolets absorptionsförmåga, bibehållande av näring, alkalinitet, stabilitet, ytarea och porositetsvolym. De olika tillämpningarna av biokol är emellertid svåra att avgöra på grund av vissa biokolegenskaper. Dessa egenskaper är framträdande under helt olika pyrolysförhållanden men kan samtidigt vara fördelaktiga för samma typ av applikation. Dessutom påverkar de olika attributen ibland varandra vilket ger upphov till komplexa trender som påverkar användningspotentialen. För att kunna dra tydliga slutsatser behövs mer forskning för att klargöra sambandet mellan biokolens attribut och för att bestämma vilken samling egenskaper hos biokol som passar bäst för varje applikation.  Hur storskalig skörd av vass kan påverka ekosystemet är fortfarande oklart. Det finns inte tillräckligt med forskning kring frågan för att kunna dra tydliga slutsatser. Detta beror på att det finns kunskapsluckor, geografiska skillnader, olika måttenheter och metoder för de studier som gjorts inom detta område. Potentialen för biokol på kolmarknaden är hög och efterfrågan i Sverige har ökat de senaste åren. Det finns också intresse för att använda biokol för jordförbättring, dels för att använda näringsinnehållet men också för att applicera biokol i jorden för att potentiellt uppnå långvarig kolbindning. Dock är produktionskostnaden för biokol gjort på vass mycket kostsam och kan därför inte konkurrera med fossilt kol eller andra gödselmedel jordförändringar på marknaden. Detta beror främst på råvaruhanteringen som är den dyraste delen av produktionen. Slutligen finns det för närvarande ingen skördemetod som kan mäta den mängd vass som behöver skördas för att kunna producera biokol i stor skala.
480

The Medieval Reception of Firdausī's Shāhnāma: The Ardashīr Cycle as a Mirror for Princes

Askari, Nasrin 02 August 2013 (has links)
Based on a broad survey of the reception of Firdausī’s Shāhnāma in medieval times, this dissertation argues that Firdausī’s oeuvre was primarily perceived as a book of wisdom and advice for kings and courtly élites. The medieval reception of the Shāhnāma is clearly manifested in the comments of medieval authors about Firdausī and his work, and in their use of the Shāhnāma in the composition of their own works. The production of ikhtiyārāt-i Shāhnāmas (selections from the Shāhnāma) in medieval times and the remarkable attention of the authors of mirrors for princes to Firdausī’s opus are particularly illuminating in this regard. The survey is complemented by a close textual reading of the Ardashīr cycle in the Shāhnāma in comparison with other medieval historical accounts about Ardashīr, in order to illustrate how history in the Shāhnāma is reduced to only a framework for the presentation of ideas and ideals of kingship. Based on ancient Persian beliefs regarding the ideal state of the world, I argue that Ardashīr in the Shāhnāma is represented as a Saviour of the world. Within this context, I offer new interpretations of the symbolic tale of Ardashīr’s fight against a giant worm, and explain why the idea of the union of kingship and religion, a major topic in almost all medieval Persian mirrors for princes, has often been attributed to Ardashīr. Finally, I compare the Ardashīr cycle in the Shāhnāma with nine medieval Persian mirrors for princes to demonstrate that the ethico-political concepts contained in them, as well as the portrayal of Ardashīr, remain more or less the same in all these works. Study of the Shāhnāma as a mirror for princes, as this study shows, not only reveals the meaning of its symbolic tales, but also sheds light on the pre-Islamic roots of some of the ethico-political concepts presented in the medieval Perso-Islamic literature of wisdom and advice for kings and courtiers.

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