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The Global ETD Search service is a free service for researchers
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Showing 261 to 270 of 330 (0.018 seconds)| 261 |
Writing Bytes: Articulating a Techno-critical PedagogyShovlin, Paul W. 16 April 2010 (has links)
No description available.
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Implementation of BECCS in a polygeneration system : - A techno-economic feasibility study in the district heating network of StockholmLinde, Linus January 2017 (has links)
The combination of Biomass Energy with Carbon Capture and Storage (BECCS) can reduce the level of CO2 in the atmosphere. It is, therefore, seen as an interesting tool in the CO2 abatement portfolio. In a Swedish context, BECCS could contribute to the goal of CO2 neutrality by 2045. This thesis aims to investigate the application of BECCS in the district heating system of Stockholm region with a case study at the energy utility Fortum Värme. The focus of the study is the technical and economic feasibility of such an application. The applicability of Fortum Värme´s plants to implement carbon capture is investigated together with costs and technical implications on each applicable plant and the district heating system as a whole. Three plants are deemed feasible for carbon capture with a cost of about 45€/tonne of captured CO2 (not including transport or storage). A model for transport of CO2 to promising storage sites in Sweden, Norway, and Denmark is constructed for transport by pipeline and ship. Ship transport is estimated to be the most cost-efficient option in all scenarios. The total cost for BECCS is calculated at 70-100€/tonne depending on size of emissions and distance to storage locations. Furthermore, the total cost is calculated to decrease by 10-25% if some current promising technologies for carbon capture reach maturity, a market for transport services of CO2 evolves, and a number of actors are sharing the costs for storage.Calculated costs are on a similar price level as other CO2 abatement strategies such as CCS in industries, biogas, and biodiesel in the vehicle fleet. If the cost is applied directly to the heat price, without any subsidies, it would increase the price of heat by 14-21%.The major challenge of BECCS in combined heat and power production, compared to other studies based on power production, is the seasonality of heat demand. The capacity of the carbon capture system will be oversized during the summer, or undersized during the winter. This is an optimization challenge which has to be further studied.
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Hydrogen liquefaction chain: co-product hydrogen and upstream study / Väteförvätskningskedja: samproduktväte och uppströmsstudieLusson, Salomé January 2021 (has links)
The European Green Deal declared that Europe must decarbonize to become carbon-neutral within 2050. To do so, the European Parliament emphasized hydrogen as a major tool for energy transition. In regard of current environmental challenges, liquid hydrogen has raised interest as energy carrier for energy storage and transport. Due to growing use of renewable energy sources such as solar and wind energy, intermittent sources will increase. Hydrogen production methods will become mostly intermittent with renewable energies. However, due to historical hydrogen production by steam methane reforming, liquefaction was developed at steady nominal charge. In order to feed current liquefaction processes with renewable hydrogen, a buffer system will become required. This thesis studies the effect of buffer and liquefaction combination on performances and cost. In order to carry out this liquefaction from intermittent source, the study is performed based on industrial data from a variable co-product hydrogen profile. This profile acts as a simplified case. The scope of the study is drawn by considering compressed hydrogen as temporary storage for the buffer while liquefaction unit is modelled around Linde Leuna cycle. The technical-economical study covers sensitivity analysis on both buffer and liquefaction unit. For the buffer unit, storage capacity, storage pressure, liquefaction flexibility and recuperation rate impacts are examined. Liquefaction sensitivity analysis includes pressure drop, electricity cost and capacity study. It is highlighted that 100% gaseous hydrogen recovery is not profitable due to high costs increase for recuperation higher than 95%. Storage pressure and capacity as well as liquefaction flexibility drive buffer cost and recuperation rate of the co-product hydrogen. Considering liquefaction study, results highlight that pressure drops cause first order deviations in energy consumption as well as on cost. Results show that the specific buffer cost is evaluated between 71% and 59% of liquefaction cost. Hence the thesis raises attention on future work on heat exchangers design, pressure drop optimization and liquefaction unit flexibility to allow an optimized renewable liquid hydrogen production.
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Energy Storage for Stationary Applications – A Comparative, Techno-Economical Investigation / Energilager för stationära applikationer – En komparativ tekno-ekonomisk studiePersson, Fredrik January 2020 (has links)
Power outages, electric-grid deficiencies and renewable energies are all examples where stationary energy storages are useful. In this master thesis, two types of stationary electrochemical energy storages are examined; vent-regulated lead-acid batteries (VRLA) and lithium iron phosphate batteries (LFP), to find out the more beneficial one in stationary uses. The techniques are examined for a large range of electric-grid services in a techno-economical investigation. The cost per delivered kWh of the energy storage is the basis of comparison which is calculated using battery degradation data with respect to C-rate, SoC, DoD, temperature, storage time and cycle frequency to estimate calendar and cyclic aging. Modelling presents neither alternative as superior although LFP is the more versatile alternative. VRLA-batteries can be a more cost-beneficial alternative for applications demanding less than 1 cycle/day, at temperatures lower than 30C, short project lifetimes and when utilizing storages beyond 80% EoL. The investment cost is lower for VRLA at equal C-rates. Cost items neglected will decrease the chances of VRLA being the cheapest technique. From a sustainability point of view, LFP is under almost all circumstances the less energy and CO2-intense technology, however recyclability is in clear favor for VRLA. / Strömavbrott, underdimensionerade elnät och förnybar energi är tre exempel där ett stationärt energilager kan tillämpas. I den här masteruppsatsen undersöks två typer av stationära elektrokemiska energilager; ventilreglerade bly-syra-batterier och litium-järnfosfat-batterier (LFP), för att finna det mer fördelaktiga alternativet i stationära applikationer. De två teknikerna analyseras i ett stort antal elnätsapplikationer i en tekno-ekonomisk studie. Kostnaden per levererad kWh av energilagret används som jämförelsebas vilken beräknas utifrån batteridegraderingsdata med avseende på C-rate, SoC, DoD, temperatur, lagringstid och cykelfrekvens för att estimera kalender- och cyklisk åldring. Modellering visar att inget av batterialternativen är överlägset i alla situationer men LFP är det mångsidigare alternativet. Bly-syra-batterier kan vara mer kostnadseffektiva för applikationer som kräver mindre än 1 (full-ekvivalent) cykel/dag vid temperaturer lägre än 30C, korta projektlivstider samt när batterilagren används bortom 80% EoL. Investeringskostnaden är lägre för bly-syra-batterier när likadan C-rate appliceras. Negligerade kostnadsposter kommer minska chanserna att bly-syra-batterier är det billigaste alternativet. Från ett hållbarhetsperspektiv är LFP nästan uteslutande den mindre energikrävande och mindre CO2-intensiva tekniken. Bly-syra-batterier har dock en klar fördel när det kommer till återvinningsbarhet.
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Running Amuq with Obsidian / A study on supra-regional socio-economic relationships in the Near East as seen through obsidian consumption practices in the Amuq Valley (S.E. Turkey) (ca. 6000-2400 B.C.E.)Rennie, Lauren 21 October 2019 (has links)
Southern Turkey’s Amuq Valley has been described as a point of convergence bridging distant regions within the ancient Near East. Through an in depth techno-typological and chemical characterization study of 290 obsidian artefacts, this research details changes in deep-time patterns of obsidian use from the Late Neolithic to Early Bronze Age (6000 BCE – 2400 BCE), arguing that shifting traditions of consumption reflect socio-economic developments both within and beyond the Northern Levant. These artefacts come from the three sites of Tell al-Judaidah, Tell Dhahab and Tell Kurdu, the material excavated during the 1930’s by the University of Chicago’s Oriental Institute. Methodologically raw material sourcing was achieved using energy dispersive X-ray fluorescence spectroscopy (EDXRF) in the well-established McMaster XRF Lab [MAX Lab]. With these artefacts’ raw materials all being exotic to the Amuq Valley, originating from various outcrops in Cappadocia, the Lake Van region and Transcaucasia (Turkey and Armenia), over 1000km away, this study not only offers new insight into how Amuq Valley communities engaged in long-distance relations, but also contributes to a larger, deep-time regional study of obsidian consumption as a proxy for understanding significant shifts in Near Eastern socio-economics, from hunter-gatherers to the earliest states. In turn, this study, by employing an Annales school framework to consider practice over deep time at the local and supra-regional level further contributes to an ‘archaeology of the long-term’. / Thesis / Master of Arts (MA) / This research involved the chemical analysis of 290 artefacts of archaeological obsidian – a naturally occurring substance made of crystallized lava - as a means of studying ancient exchange systems in the Near East. More specifically, this study covers archaeological periods from 6000 B.C.E. (Late Neolithic) to 2400 B.C.E. (Early Bronze Age) in the Amuq Valley region of southern Turkey. These artefacts were procured during excavations under the Oriental Institute Museum (University of Chicago) beginning in the 1930s. All artefacts are exotic to the Amuq Valley from several known obsidian outcrops in Anatolia (Turkey), some over 1000km away. Analysis was conducted using X-ray fluorescence (XRF) to match each artefact to its geological origin thereby identifying the range of exotic materials were exchanged across long-distances. The goal of this research was to uncover social and/or economic dynamics of the Amuq Valley through deep-time with regards to the greater obsidian trade network of the Near East.
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Agrivoltaic Implementation in Greenhouses : A Techno-Economic Analysis of Agrivoltaic Installations for Greenhouses in SwedenGauffin, Henrik January 2022 (has links)
Due to the growing population and climate change, the world will see an increase in demand for food, freshwater and renewable energy supply. Agrivoltaics has the possibility to address all these problems, by producing food and renewable energy but also by reducing water usage in agriculture. This thesis aims to study if agrivoltaics including storage has the potential to enable sustainable greenhouses in Stockholm, Sweden by trying to create a near net zero energy consumption for greenhouses with Agrivoltaics (AV) implemented. Furthermore a techno-economic assessment will be made for the AV-systems where Key Performance Indicator (KPI)’s are compared to economic parameters. The selected KPI’s were a near net zero energy consumption and irradiance underneath the Photovoltaics (PV) technology. The selected PV-technology was standard PV-modules, Semi-Transparent Module (STM) and Organic Solar Cell (OSC) PV. These technologies were paired with li-ion batteries between 0-100 kWh and simulated in the software System Advisor Model (SAM) over a 25 year period. The AV system was applied to two load profiles, one for indoor plants and one for tomatoes. The economic parameters calculated was Net Present Value (NPV), Net Capital Cost (NCC), and Levelised Cost of Electricity (LCOE). The results showed that the system is efficient in summertime where the PV reached maximum capacity in summer and the battery works as a complement. In wintertime, the AV-system is not very efficient and most of the electricity comes from the grid. It was not possible to create a near net zero energy consumption including storage in Stockholm Sweden. The irradiance beneath the panels were at a maximum for OSC, it was slightly reduced for the STM, and below 50% for the standard PV-module, depending on the size of the AV-system. Depending on the shade tolerance of the plant, the PV-technology should be selected.
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ADVANCING CARBON NEUTRALITY : Techno-economic analysis of Direct Air Capture at commercial scaleNilsson, Martin January 2024 (has links)
In light of escalating concerns over climate change and the imperative to mitigate greenhouse gas emissions, particularly carbon emissions, the pursuit of negative emissions technologies (NETs) has gained significant attention. Direct air capture (DAC) stands out as a promising avenue, offering the potential to actively remove carbon dioxide from the atmosphere. This degree project provides a thorough examination of two leading DAC projects, Mammoth and Stratos, which exemplify innovative approaches to achieving negative emissions at scale. By employing low-temperature DAC (LT DAC) and high-temperature DAC (HT DAC) respectively, Mammoth and Stratos confront the challenge of carbon capture with distinct technological strategies. This degree project employs a Techno-Economic Analysis (TEA) to estimate the Levelized Cost of CO2 Capture through DAC (LCOD), revealing Mammoth'sLCOD at $260/tCO2and Stratos at $608/tCO2, excluding costs for carbon transport and storage.The TEA is followed up with a Sensitivity Analysis to assess how the LCOD is affected by variations in input parameters, such as capital costs and electricity demand/costs among several parameters. Furthermore, this degree project identifies that uncertainties remain regarding the carbon storage solution, including its efficiency, long-term environmental implications, and associated costs. Given the Stratos projects’ dependence on Enhanced Oil Recovery (EOR) as the method of storing the captured carbon, the concern regarding efficiency and environmental implications is particularly relevant, as this method could potentially optimize oil production by 5-20%. As the discourse on DAC continues to evolve, this degree project advocates for the integration of Life Cycle Analysis (LCA) to comprehensively evaluate environmental impactsof both projects. This would guide the path towards sustainable carbon capture solutions, aiding in informed decision-making and guiding future DAC endeavors.
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Le phénomène acheuléen en Europe Occidentale : approche chronologique, technologie lithique et implications culturelles / THE ACHEULIAN PHENOMENON IN WESTERN EUROPE : Chronological approach, lithic technology and cultural implications / IL FENOMENO ACHEULEANO IN EUROPA OCCIDENTALE : Approccio cronologico, tecnologia litica e implicazioni culturali / EL FENÓMENO ACHEULEANO EN EUROPA OCCIDENTAL : Enfoque cronológico, tecnológia litica e implicaciones culturales / DAS PHÄNOMEN DES ACHEULÉENS IM ABENDLÄNDISCHEN EUROPA : Chronologischer Ansatz, lithologische Technologie und kulturelle AuswirkungenNicoud, Elisa 10 May 2011 (has links)
La diversité historique et substantielle de l’Acheuléen d’Europe occidentale est perceptible d’un point de vue phénoménologique. Chacune des 36 séries lithiques de France, d’Angleterre, d’Italie et d’Espagne étudiées dans ce travail présente une production originale. Le phénomène bifacial peut être dissocié des autres manifestations de l’Acheuléen : les pièces bifaciales sensu stricto apparaissent massivement dans le nord de l’Europe autour de l’OIS 11 puis sur le pourtourméditerranéen vers l’OIS 9 mais sous une forme différente, engendrant des modifi cations majeures de toute la production. L’analyse critique des contextes lithostratigraphiques et la prise en compte des diversités technique, technologique ou chronologique des industries permettent de reconsidérer le paradigme de la diffusion « Out of Africa ». Tout conduit à proposer l’hypothèse d’une invention locale de la pièce bifaciale et de son évolution sur place. Le terme a trop longtemps masqué la véritable diversité du Paléolithique inférieur tout entier. C’est vers l’analyse de la pluralité des comportements humains et des sociétés qu’il faut se diriger maintenant. / The historic and substantial diversity of the Western European Acheulian can be perceived from a phenomenological standpoint. All of the 36 lithic assemblages studied in France, England, Italy and Spain provide an original production. The bifacial phenomenon can be separated from other expressions of the Acheulian. Indeed, bifacial pieces, in the strict sense, appear in great numbers in northern Europe around the OIS 11 and in the Mediterranean region around the OIS 9. However, the latter are found under different forms, which imply major modifi cations of all the production. The critical analysis of lithostratigraphic contexts and the consideration of technical, technological and chronological diversities, allow reconsidering the paradigm of the « Out of Africa » diffusion. The hypothesis of a local invention and evolution of bifacial pieces can be put forward. The use of this term has limited our perception of the Lower Paleolithic as a whole. One should now focus on analyzing the diversity of human behaviors and societies.
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Le double visage des inventions biotechnologiques, une source potentielle de risques majeurs / The double face of biotechnological inventions, a potential source of major risksLaporte, Sylvie 19 October 2011 (has links)
Les inventions biotechnologiques ont un double visage, une face bienveillante et une face terrifiante, chacune source potentielle de risques majeurs. Comment les contrôler et les réguler ? La recrudescence des catastrophes majeures (crises sanitaires) liées à l’usage de produits biotechnologiques, d’une part, puis l’échec à l’adoption d’un protocole de vérification à la Convention d’interdiction des armes biologiques suivi de l’émergence de nombreuses publications à risques dans le domaine des biotechnologies, d’autre part, démontrent l’omniprésence et la transversalité de cette problématique. Par leur essence duale, les biotechnologies appellent des solutions globales. La voie d’une gestion cohérente semble s’ouvrir au travers d’un corps de règle prenant tous ces paramètres en considération, les risques majeurs. L’avantage de cette législation, si elle admet une modification préalable de la nomenclature des risques majeurs en y intégrant les risques liés aux conflits, reposera sur sa globalité et sur la responsabilisation de tous. Face à une menace biotechnologique qui est perçue comme dominante dans les années à venir, l’émerge d’un ordre public mondial favorable à un accroissement de la responsabilité des Etats à l’égard de la sécurité humaine serait souhaitable. Le but de toute institution étatique étant de garantir à ses ressortissants leur sécurité et leur sûreté quelles que soient les circonstances, cet ordre public pourrait trouver ses bases au sein des réglementations relatives aux droits de l’homme et au droit de l’environnement ; réglementations déjà émancipées de la distinction entre situations de paix, de crises ou de conflits / The biotechnological inventions have a double face, a kindly face and a terrifying face, each potential source of major risks. How to control them and to regulate them? The outbreak of the major disasters (sanitary crisis) bound to biotechnological products, on one hand, the failure to the adoption of a Protocol to the Biological Weapon Convention, followed by the emergence of numerous publications at risks in the field of biotechnology, on the other hand, demonstrate the omnipresence and the transverse character of this problem. By their duality, biotechnologies need global solutions. The way of a coherent management seems to open through a body of rule considering all these parameters, the major risks. The advantage of this legislation, if it admits a preliminary modification of the list of the major risks by integrating the risks connected to the conflicts, will be based on its global aspect and everyone’s responsibility. In front of biotechnological threat, which is perceived as dominant in the years to come, an emergent world law and order favourable to an increase of the responsibility of States towards the human safety would be desirable. The purpose of any state institution is the guarantee of Nationals safety, whatever circumstances are, this law and order could find its bases within the regulations relative to human rights and to environmental law; these regulations are already indifferent to the distinction between situations of peace, crisis or conflicts
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En "Rave" et contre tout ? Dimensions festives et oppositionnelles du monde des free parties / Irr(a)verent? Festive and Oppositional Dimensions of the World of Free PartiesPlouchard, Nathalie 16 June 2017 (has links)
Au carrefour de la sociologie de la culture et de la sociologie de la déviance, ce travail porte sur les dimensions festives et oppositionnelles du monde des free parties, qui s’articule autour de manifestations techno clandestines et marginales. A partir d’une enquête ethnographique, il s’agit d’examiner une pratique culturelle et musicale mais aussi de saisir la variété des expressions oppositionnelles que les jeunes engagés dans ce monde y déploient. A la suite d’un travail de clarification théorique, cette recherche s’inspire de la notion de contre-culture, dans laquelle l’idée de conflictualité est centrale. Cet outil conceptuel permet d’explorer diverses facettes de l’univers free, controversé et encore largement méconnu, et notamment sa composante « contre ». On peut ainsi montrer que, si le monde free est loin d’être réductible à ses dimensions oppositionnelles, celles-ci peuvent donner un relief particulier à la fête – et réciproquement. La pertinence du croisement entre l’objet « free parties » et l’outil conceptuel « contre-cultures » est due en partie à la double déviance, sociale et légale, qui caractérise les fêtes techno étudiées. Les différents aspects oppositionnels mis en évidence dans ce monde juvénile, ainsi que la distinction entre non-conformité et contestation qui en émane, permettent d’analyser le rapport entre déviance, illégalité, conflictualité/illégalité à la lumière du cas des free parties. / At the crossroads of the sociology of culture and the sociology of deviance, this work focuses on the festive and oppositional dimensions of the free party world, which revolves around clandestine and marginal techno events. Based on an ethnographic research, this study aims to examine a cultural and musical practice but also to grasp the various oppositional expressions unfolding within this youth culture. After providing a theoretical clarification, I draw on the notion of counterculture, in which the idea of conflict is central. This conceptual tool enables me to explore various facets of the free party universe, controversial and still largely misunderstood, and in particular its antagonistic elements. Thus I show that, while the free party world does not amount to its oppositional dimensions, the latter can enhance the festive experience – and vice versa. The double deviance – both social and legal – characteristic of the studied techno parties makes it all the more relevant to bring together this object of study and the concept of counterculture. The various oppositional aspects of this youth culture I highlight, as well as the resulting distinction between nonconformity and contention, enable me to analyze the relationship between deviance, illegality, and conflict/counterculture in the light of the case of free parties.
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