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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.
131

Design and assessment of novel thermochemical plants for producing second and third generation biobutanol / Design of thermochemical plants for biobutanol production

Okoli, Chinedu January 2016 (has links)
The use of biofuels as an alternative to gasoline in the transportation sector is seen by policy makers as an important strategy to reduce global greenhouse gas emissions. Biobutanol is one such biofuel that is gathering increasing attention in the biofuel community, because of its preferable fuel qualities over bioethanol. However, despite increasing research into biobutanol production, the thermochemical route for biobutanol production has not been adequately studied in the peer-reviewed literature. In light of this motivation, this thesis considers the design, and economic and environmental assessment of thermochemical plants for producing second and third generation biobutanol. In addition, the potential for using process intensification technology such as dividing wall columns (DWC) in place of conventional distillation columns is also investigated as a way to improve thermochemical biobutanol plants. As a first step, a novel thermochemical plant for producing second generation biobutanol is developed. Detailed economic analysis of this plant show that it is competitive with gasoline under certain process, and market conditions. The designed plant is then extended, with some modifications, to evaluate the economic and environmental potential of a thermochemical plant for producing third generation biobutanol from macroalgae. It was concluded from the results that the thermochemical route is preferable for producing second generation biobutanol over third generation biobutanol. The novel thermochemical plant design is then updated by using a kinetic model of a pilot-scale demonstrated catalyst to represent the critical mixed alcohol synthesis reaction step. This change allows optimal unreacted syngas recycle configurations for maximizing butanol yield to be established. Furthermore, integrating a DWC, designed using a methodology developed in the thesis, into the updated thermochemical plant leads to additional plant improvements. Overall, the work carried out in this thesis demonstrates that the thermochemical route is a viable option for producing second generation biobutanol. / Thesis / Doctor of Philosophy (PhD)
132

Global Techno-Capitalism and the Production of Hate: Understanding Political-Economic and Ideological Utility on YouTube and Gab

Esmonde, Jonathan Spencer 07 1900 (has links)
The production of Hate, albeit a historical, long-existing, and relentless process, has been reinvigorated by the simultaneously globalizing and localizing power of cyberspace. Techno-capitalism, often perceived as the actuating force of neoliberal globalization, has emanated novel formations of social interaction, community formation, the dissemination of ideology, and political mobilization. Far-right ideology is being globalized throughout popular social cyberspaces like YouTube by thought leaders or ideological entrepreneurs, while users then localize within alternative social cyberspaces like Gab, wherein their beliefs are reaffirmed, identities are consolidated, and communities are formed. This process is integral to the materialization of far-right extremism, manifested as political action in real, physical space, and thus, illuminates new expressions of real virtuality, various politics of scale, and contemporary consequences of neoliberal globalization.
133

Integrated sewage sludge treatment scenarios – techno-economic analysis on energy and phosphorus recovery

Bagheri, Marzieh January 2022 (has links)
Sewage sludge is a by-product of wastewater treatment that simultaneously gathers contaminants, valuable organic matter, and nutrients. The treatment of the increasing amount of sewage sludge is important from both pollution prevention and resource recovery perspectives as i) large shares of mineral phosphorus, listed as a critical raw material, terminate in the sewage sludge, and ii) energy recovery from sewage sludge can cover the energy-intensive demand of the treatment process. Previous research has identified sewage sludge combustion as a suitable treatment approach as it both addresses contaminant destruction and paves the way for efficient phosphorus recovery from the sewage sludge ash. The commercial development of this practice has, however, been slow. Therefore, this thesis aims to investigate the challenges in sustainable sewage sludge management, and to, in more detail, identify the economic viability of energy and phosphorus recovery from sewage sludge through combustion. The thesis’ aim is divided into two objectives addressed in three papers. First, to investigate how different aspects of sewage sludge management, such as contaminants, economic efficiency, technical aspects, and legislation, evolve and interact. This has been done by a review of sewage sludge management research over fifty years (Paper I). Second, to investigate the economic viability of simultaneous energy and phosphorus recovery from sewage sludge by comparing different technology and market scenarios. This has been done for i) new sewage sludge mono-/co-combustion plants (Paper II), and ii) the integration of treatment technologies, mainly anaerobic digestion, hydrothermal carbonization, and combustion, in an existing wastewater treatment plant (Paper III).  Results from the analysis of sewage sludge management research (Paper I) show a narrow-focused perspective that often excludes inseparable aspects such as combination of economic consideration and advanced extraction technology. The investment viability of a new mono-/co-combustion of sewage sludge (Paper II) is highly conditional on heat, electricity, and fertilizer price, and external financial support is often a crucial requirement. Sewage sludge co-combustion with potassium-rich biomasses improves sewage sludge quality and forms usable ash as fertilizer without further need for phosphorus recovery technology. In this case, the economic feasibility of the process is independent of usable ash revenue, which stimulates a competitive selling price for the ash, thereby improving the marketing of sludge-based fertilizer. Avoided disposal costs of sewage sludge for a retrofitted wastewater treatment plant by introducing hydrothermal carbonization (Paper III) shows good economic feasibility while recovering phosphorus. Integrating anaerobic digestion, hydrothermal carbonization, and combustion may also improve investment incentives by improving energy outputs and phosphorus recovery. The economic feasibility is contingent on product (hydrochar, heat, electricity) prices and sensitive to added equipment costs, and costs for sludge transportation and disposal.
134

Understanding the Relationship between Sustainability and Technology: Perspectives of Young Sustainability Practitioners in For-Profit Organizations

Hehl, Anna Pauline January 2023 (has links)
One of the most critical issues of our time is sustainability. Simultaneously, techno optimism is prevailing in public discourse suggesting that technology will create a sustainable future without requiring drastic changes. Despite the connection that is often drawn between technology and sustainability and the presence of technologies in organisations, research combining the two concepts remains limited and does not account for the interplay of social values and technological artefacts. To overcome this incomplete picture of technology, this thesis employs sociomateriality to investigate how sustainability and technology are understood in relation to each other by young sustainability practitioners in for-profit organisations. Following the social constructivist philosophy, nine semi-structured interviews were conducted which show that practitioners recognise the environmental and social limits to development and use the triple bottom line (TBL), consisting of economic, environmental and social dimensions to translate sustainability into organisations. However, TBL implementation varies between organisations showing the difficulty of unifying organisational sustainability in one concept. Furthermore, young sustainability practitioners understand technology as sociomaterial, describing the interplay between an artefact’s affordances and restraints, and the practitioner’s configuration work that co-create outcomes. Moreover, the interviewees are optimists not because they rely on technology, but they believe in human’s ability to change which differs from techno optimism. It can be concluded that practitioners are critical about relying on technology for sustainability and believe that sustainability is created through an interplay of humans with technology, transferring responsibility to humans. When it comes to creating a sustainable future, they first struggled to envision an alternative future beyond technological developments but started imagining when given space to reflect. One outcome of the research is that young sustainability practitioners must be given room to reflect on their understanding of sustainability, technology and their relationship as the first step to taking actions to create the future.
135

Starkare ljud, mer intressant? : En kvalitativ studie hur musikproduktionsstudenter påverkas av starkt ljud i hörlurar

Mattsson, Malin January 2024 (has links)
Under en längre tid har fenomenet ”loudness war” varit föremål för omfattande diskussioner. Trots detta finns en begränsad mängd information angående musikproduktionsstudenters syn på stark musik, inom olika genrer ur ett kvalitativt perspektiv. Denna uppsats undersöker loudness och loudness war utifrån ett industriellt techno-perspektiv samt musikproduktionsstudenters uppfattning om stark musik vid användning av hörlurar. Metoderna som tillämpades var lyssningstester och enkäter. Där fick studenter uttryckte sina åsikter om ämnet och angav den föredragna ljudstyrkan enligt deras bedömning. Resultaten från undersökningen visade att den mest komprimerade versionen var föredragen. Dock så visade studenterna även en preferens för mindre komprimerade versioner. Studien har bidragit med ny insikt gällande loudness inom industriell techno samt skillnader i ljudupplevelsen mellan mer och mindre komprimerade musikstycken.
136

Expansion of Reaction Network Flux Analysis toward including Life Cycle Assessment and Ecosystem Services

Motianlifu, Muzhapaer 11 August 2017 (has links)
No description available.
137

Designing for Body Awareness - A Study on Enabling Body Awareness in Mindfulness Through Wearable Haptic Thermal Technology

Brolin, Lisa January 2017 (has links)
A stressful society with a deficiency of attention has led to a growing demand for meditation techniques. One meditation technique is mindfulness, which is a tool used to reduce stress, intensify body awareness and to help us be more present. However, as mindfulness requires extensive training and dedication, many beginners may decide to quit practicing in the initial phase and may risk not ever experiencing the benefits of body awareness. Previous studies indicate that technology is often blamed for the deficiency of attention. Therefore, this study addresses the possibilities to design technology for sustained attention. More precisely, the study aims to investigate what potential possibilities wearable haptic technology has in enabling body awareness in body scan meditation in mindfulness. It also aims to explore how beginners in mindfulness experience the use of wearable haptic technology in body scan meditation. The study explores these problems by combining research through design and action research, with three phases of iteration, resulting in the design, implementation and evaluation of the wearable prototype HeatCue with haptic thermal feedback. The study implies that HeatCue provides an intimate, subtle and skin-close interaction, suitable for the context of body scan mediation. The results indicate that wearable haptic technology with thermal feedback holds the possibility to enable body awareness in body scan meditation through acting as a reminder for the body part where the feedback is applied, a reference for the rest of the body as well as encouragement. Furthermore, the study shows that wearable haptic technology is beneficial in evoking emotions and interest. The study also indicates some key aspects when designing for body awareness, namely; subtlety and interplay of the feedback, a secluded environment and an understanding that each individual is different. The study contributes to a deeper understanding of designing for body awareness and to new knowledge in the field of wearable haptic technology with thermal feedback and techno-spirituality in human-computer interaction
138

Techno-economic assessment of CO2 refrigeration systems with geothermal integration : a field measurements and modelling analysis

Giunta, Fabio January 2020 (has links)
Several CO2 transcritical booster systems in supermarkets use the potential of integrating geothermal storage, enabling subcooling during warm climate conditions as well as being a heat source during cold climate conditions. First of all, field measurements of one of these systems located in Sweden were analysed with particular focus on the heat-recovery performance. The best theoretical operational strategy was compared to the one really implemented and the differences in the annual energy usage were assessed through modelling. The results show that an alternative to the best theoretical operational strategy exists; heat can be extracted from the ground while low-temperature heat is rejected by the gas cooler. Such an alternative strategy has important technical advantages with a negligible increment of the energy usage. In the second part of this work, the benefits of geothermal subcooling were evaluated. Applying the BIN hours method, it was demonstrated that this system is expected to save on average roughly 5% of the total power consumption, in Stockholm’s climate. The models utilized for the winter and summer season were combined to find the relationship between geothermal storage size and annual energy savings. In this way, it was possible to calculate the present value of the operational savings for the study case. Furthermore, a general methodology for assessing the economic feasibility of this system solution is presented. Finally, several scenarios were investigated to produce parametric curves and to perform a sensitivity analysis. Comparing the results with the typical Swedish prices for boreholes, the cases where this system solution is economically justified were identified. These are supermarkets with a Heat Recovery Ratio (HRR) higher than the average. For examples, supermarkets supplying heat to the neighbouring buildings (considering the Stockholm’s climate, systems with an annual average HRR of at least 70%). Relying only on savings from subcooling was found to be not enough to justify a geothermal storage, a not-negligible amount of heat must be extracted in winter. Finally, some interesting concepts and alternatives to a geothermal integration are presented to point out relevant future work.
139

Azelio’s Thermal Battery for Combined Heat and Power : A Thermo-economic and Market Research Study

Lantz, Martin January 2020 (has links)
The objective of this thesis was to assess the market opportunities for two novel Carnot battery system solutions, one supplying power and low temperature heat as well as a system supplying medium temperature heat exclusively. To fulfill the objective, a methodology was developed and implemented to investigate the market potential, further two techno-economic models were developed and utilized to investigate the performance of such Carnot battery solutions. Based on the market review four industrial sectors were identified as most interesting and the geographical scope was confined to Europe. Further, case studies were developed to mimic two different sizes of manufacturing plants, a small and large, for the identified sectors. The cases were then implemented to the techno-economic analysis to compare the performance of a new Carnot battery system against the conventional energy solutions. The identified market offers a vast opportunity for incorporating Carnot battery solutions to meet the industrial sectors requirements, both from a technical and market size perspective. The market review combined with the techno-economic analysis indicates that the heat market is interesting as long as fuel, power grid costs and industrial operations are at the ideal level. For the Carnot battery system supplying both power and heat, it was found that yearly cost savings in the range of 10-15 % could be achieved for the identified market. The added value of incorporating heat generation and surplus power from PV had a strong effect on the business case. Through sensitivity analysis it was approximated that locations in central/south Europe with global horizontal irradiance (GHI) above 1500 kWh/m2 would benefit from the solution. For the Carnot battery system supplying medium temperature heat it was found that solutions would struggle with feasibility for the given market conditions. Through sensitivity it was found that locations with GHI higher than 2100 kWh/m2 would benefit from the solution. For both models it was found that the hybrid solution, Carnot battery combined with on-site PV, yields the most feasible solution for the end user, compared to charging the Carnot storage system from the power grid. Both models were sensitives to changes in energy cost for operating the old conventional system as well as operations times of the industries. The availability of space is a major constraint to implement Carnot battery solutions, as both the Carnot battery as well as PV plant require substantial space. It was found through literature and interviews that industries with close proximity to end customer and which faces pressure to decarbonize, may be most interesting to target, as for e.g. the Food and beverage sector. / Syftet med denna uppsats var att undersöka marknadspotentialen för två stycken Carnot batterisystem, ett system som generar både el och låg tempererad värme och ett som endast generar medel tempererad värme. För att uppnå målet så utvecklades och implementerades en metod för att undersöka marknadspotentialen, vidare så utvecklades och användes två tekno-ekonomiska modeller för att undersöka prestandan för de två Carnot lösningarna. Baserat på marknadsundersökningen så identifierades fyra industriella sektorer som mest intressanta och baserat på dem begränsades omfattningen av studien till Europa. Från marknadsgenomsökningen och de identifierade industriella sektorerna skapades två olika profiler för att representera en liten och stor industri för de identifierade sektorerna. Profilerna användes som utgångspunkt för den tekno-ekonomiska analysen för att jämföra prestandan hos ett nytt Carnot batterisystem mot konventionella energilösningar. Den identifierade marknaden erbjuder en stor möjlighet för att integrera Carnot batterilösningar för att möta industrisektorns krav, både ur ett tekniskt perspektiv och med tanke på marknadensstorleken. Marknadsundersökningen kombinerat med tekno-ekonomiskanalysen indikerar att värmemarknaden för industrier är intressant så länge bränsle- och elkostnader samt drifttiden är i rättnivå. Resultat från analysen tyder på att Carnot batterilösningar, som generar både el och värme, kan skapa energikostnadsbesparingar runt 10–15 % för den identifierade marknaden. Värdet av att addera kassaflöden från överskotts el från solcellerna samt värmegenerering har en stark påverkan på resultaten. Från en känslighetsanalys gick det att identifiera centrala/södra Europa som platser med tillräcklig solinstrålning (runt 1500 kWh/m2) för att dra nytta av ett Carnot batteri. För Carnot batterisystemet som endast producerar medel tempererad värme så skapas inga energikostandsbesparingar för slutanvändaren för den analyserade marknadsförutsättningarna. Genom en känslighetsanalys gick det att fastställa att hög solinstrålning krävs (över 2100 kWh/m2) för att slutanvändaren ska skapa några besparingar med systemet. För båda modellerna generade en hybridsystemlösning med både Carnot batteri samt lokal solcellsanläggning de bästa resultaten, jämfört med om systemet skulle laddas från elnätet. Båda modellerna är känsliga mot förändringar i energikostnader, värme eller el, för det konventionella systemet samt lägre drifttid. Vidare så är tillgänglig yta en annan restriktion som både kan hindra implementeringen av Carnot batteriet samt också solcellsanläggningen. Både litteraturstudien och de genomförda intervjuerna tyder på att industrier som har nära kontakt med slutkonsumenten och som har krav på att reducera sin miljöpåverkan, är en intressant användare av ett Carnot batterilösning, som exempelvis livsmedelsindustrin.
140

Techno economic assessment of CCUS for a biogas facility in Sweden : Evaluating the economic feasibility for three CCUS concepts / Tekno-ekonomisk undersökning av CCUS för en biogasanläggning i Sverige

Johansson, Tobias, Knutsson, Markus January 2022 (has links)
Many countries strengthen their commitments to reduce greenhouse gas emissions to limit climate change and meet the Paris Agreement (Masson-Delmotte et al., 2019). Commitments include achieving net-zero emissions or in some cases even negative emissions (Government offices of Sweden, 2020a; United Nations, 2021a). To achieve these goals, carbon dioxide capture, utilization, and storage (CCUS) is considered as an essential strategy. Carbon capture storage and utilization are recognized methods of reducing or avoiding greenhouse gas emissions (IEA, 2019a, 2020). However, the uncertainty regarding costs, financial incentives, and pricing is impeding adoption. Further information is needed for CCUS concepts both in respect to cost estimates and required market prices for CCUS, this to provide guidance for decision makers and market actors. In this report a study has investigated the economic feasibility of three CCUS concepts for a biogas facility. One CCS concept where CO2 was captured and liquefied on-site to be transported to a terminal for shipping and end storage injection. The CCS concept annual capacity was ~16 500 ton net stored CO2. Two CCU concepts were considered, where synthetic natural gas (SNG) was produced via biologic methanation with on-site produced hydrogen, both with annual production of ~88 GWh SNG. A techno-economic assessment (TEA) was carried out where the key cost-drivers were identified, and the economic feasibility assessed. With performance and cost estimates for each process step in the different considered concepts a model was built where a cash flow was created and a net present value (NPV) could be calculated. The study found transportation to be the most prominent cost driver for CCS where shipping and storage represented 57 % of the total cost of CO2 removal. The cost driver for CCU concepts was found to be hydrogen production, where the electricity for the electrolyser constituted 65 % of the total cost of produced SNG. None of the concepts were found economic feasible when the Swedish market was considered. The break-even price for CO2 removal in the CCS concept was found to be 151 €/ton, just above the assumed base value used in this study. As the voluntary market is still undeveloped it is difficult to know what price that could be expected, however, in discussion with market experts a range between 150-200 €/ton would not be unthinkable for the concept studied. For the CCU concepts to be economically feasible, the estimated minimum price levels for SNG were 184 and 193 €/MWh respectively. Comparing to the benchmark price of diesel of 125 €/MWh, both CCU concepts were concluded to be unfeasible. The sensitivity analysis showed that the CCU concepts were very sensitive to variations in electricity price. When the German fuel market was considered, all studied concepts yielded a positive business case. CCS was the only concept showing economic feasibility, while the CCU concepts remained unfeasible. In the German market a GHG reduction quota credit was accounted for which was valued higher than the carbon removal credits in the voluntary market. / Många länder stärker sina åtaganden att minska utsläppen av växthusgaser för att begränsa klimatförändringen och uppfylla Parisavtalet (Masson-Delmotte et al., 2019). I åtagandena ingår att uppnå nettonollutsläpp eller i vissa fall till och med negativa utsläpp (Regeringskansliet, 2020a; FN, 2021a). För att uppnå dessa mål anses avskiljning, nyttjande och lagring av koldioxid (CCUS) vara en viktig strategi. Avskiljning, lagring och utnyttjande av koldioxid är erkända metoder för att minska eller undvika utsläpp av växthusgaser (IEA, 2019a, 2020). Osäkerheten kring kostnader, ekonomiska incitament och prissättning hindrar dock införandet. Ytterligare information behövs för CCUS-koncept både när det gäller kostnadsberäkningar och nödvändiga marknadspriser för CCUS, detta för att ge vägledning för beslutsfattare och marknadsaktörer. I den här rapporten undersöks den ekonomiska genomförbarheten av tre CCUS-koncept för en biogasanläggning. Ett CCS-koncept där koldioxid avskiljs och kondenseras på plats för att sedan transporteras till en terminal för slutlig sjöfrakt och injektion i geologiskt lager. Den årliga kapaciteten för CCS-konceptet var ~16 500 ton nettolagrad koldioxid. Två CCU-koncept övervägdes, där syntetisk natur gas (SNG) producerades genom biologisk metanisering med vätgas producerad på plats, där båda koncepten hade en årlig produktion av ~88 GWh SNG. En tekno-ekonomisk undersökning genomfördes där de viktigaste kostnadsdrivande faktorerna identifierades och den ekonomiska genomförbarheten bedömdes. Med hjälp av prestanda- och kostnadsberäkningar för varje processteg i de olika tänkta koncepten byggdes en modell där ett kassaflöde skapades och ett netto-nuvärde kunde beräknas. I studien konstaterades att transport var den mest framträdande kostnadsdrivande faktorn för CCS, där sjöfrakt och lagring stod för 57 % av den totala kostnaden för koldioxidavskiljning. Kostnadsdrivande för CCU-konceptet var vätgasproduktionen, där el till elektrolysen utgjorde 65 % av den totala kostnaden för producerad SNG. Inget av koncepten befanns vara ekonomiskt genomförbart när den svenska marknaden beaktades. Nollpunktspriset för koldioxidavskiljning i CCS-konceptet fanns vara 151 euro/ton, vilket är strax över det antagna basvärde som används i denna studie. Eftersom den frivilliga marknaden fortfarande är outvecklad är det svårt att veta vilket pris som kan förväntas, men i diskussioner med marknadsexperter skulle ett prisintervall på 150-200 €/ton inte vara otänkbart för det studerade konceptet. För att CCU-koncepten ska vara ekonomiskt genomförbara var de uppskattade minimipriserna för SNG 184 respektive 193 €/MWh. Jämfört med referenspriset för diesel på 125 €/MWh, ansågs båda CCU-koncepten vara ekonomiskt ogenomförbara. Känslighetsanalysen visade att CCU-koncepten var mycket känsliga för variationer i elpriset. När den tyska bränslemarknaden beaktades gav alla studerade koncept ett positivt netto-nuvärde. CCS konceptet var det enda konceptet som ansågs vara ekonomiskt genomförbart, medan CCU-koncepten förblev ogenomförbara. På den tyska marknaden räknades en kvot för minskning av växthusgasutsläpp in, som värderades högre än de krediter för avskiljning av koldioxid som fanns på den frivilliga marknaden.

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