| 1. |
- Adekunle, Kayode
(author)
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Bio-based Composites from Soybean Oil Thermosets and Natural Fibers
- 2011
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Doctoral thesis (other academic/artistic)abstract
- In order to reduce over-dependency on fossil fuels and to create an environment that is free of non-degradable plastics, and most importantly to reduce greenhouse gas emission, bio-based products are being developed from renewable resources through intense research to substitute conventional petrochemical-based plastics with renewable alternatives and to replace synthetic fibers with natural fibers. Many authors have done quite a lot of work on synthesizing polymers from renewable origin. Polylactic acid (PLA) has been developed and characterized, and it was found that it has enormous potential and can serve as an alternative to conventional thermoplastics in many applications. Modification of the plant oil triglycerides has been discussed by many authors, and research is still going on in this area. The challenge is how to make these renewable polymers more competitive in the market, and if possible to make them 100% bio-based. There is also a major disadvantage to using a bio-based polymer from plant oils because of the high viscosity, which makes impregnation of fibers difficult. Although natural fibers are hydrophilic in nature, the problem of compatibility with the hydrophobic matrix must be solved; however, the viscosity of the bio-based resin from plant oils will complicate the situation even more. This is why many authors have reported blending of the renewable thermoset resin with styrene. In the process of solving one problem, i.e reducing the viscosity of the renewable thermoset resin by blending with reactive diluents such as styrene, another problem which we intended to solve at the initial stage is invariably being created by using a volatile organic solvent like styrene. The solution to this cycle of problems is to synthesize a thermoset resin from plant oils which will have lower viscosity, and at the same time have higher levels of functionality. This will increase the crosslinking density, and they can be cured at room temperature or relatively low temperature. In view of the above considerations, the work included in this thesis has provided a reasonable solution to the compounded problems highlighted above. Three types of bio-based thermoset resins were synthesized and characterized using NMR, DSC, TGA, and FT-IR, and their processability was studied. The three resins were subsequently reinforced with natural fibers (woven and non-woven), glass fibers, and Lyocell fiber and the resulting natural fiber composites were characterized by mechanical, dynamic mechanical, impact, and SEM analyses. These composites can be used extensively in the automotive industry, particularly for the interior components, and also in the construction and furniture industries. Methacrylated soybean oil (MSO), methacrylic anhydride-modified soybean oil (MMSO), and acetic anhydride-modified soybean oil (AMSO) were found to be suitable for manufacture of composites because of their lower viscosity. The MMSO and MSO resins were found to be promising materials because composites manufactured by using them as a matrix showed very good mechanical properties. The MMSO resin can completely wet a fiber without the addition of styrene. It has the highest number of methacrylates per triglyceride and high crosslink density.
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| 2. |
- Agrawal, Tarun Kumar
(author)
-
Contribution to development of a secured traceability system for textile and clothing supply chain
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Secured traceability implies not only the ability to identify, capture, and share required information on product transformation throughout the supply chain (SC), but also the ability to ensure the security of the traceability data. Due to information asymmetry and lack of transparency, textile and clothing (T&C) industries often face challenges in implementing and maintaining sufficient traceability. The SC actors find it difficult to identify and track the suppliers and sub-suppliers involved. Additionally, the opaque and largely untraceable structure of the SC has enabled the easy intrusion of counterfeits. Hence, a secured traceability system is imperative to ensure that the required traceability data are captured and shared among SC actors, thereby allowing the tracking and tracing of the products in the SC. Further, a secured traceability system helps organizations in various decision-making processes and protects customers from counterfeits. This thesis contributes to the development of a secured traceability system for the T&C sector. It examines traceability at product and information levels, based on the system-of systems approach. At the product level, the thesis introduces a secured traceability tag that can be printed on the textile surface. The secured tag is hard to copy and is durable enough to withstand normal textile use, thus providing sufficient security besides product tagging for traceability implementation. At the information level, the thesis explores and classifies traceability data that can be shared at business-to-business and business-to customer levels for the implementation of secured traceability. Subsequently, a block chain-based traceability framework is proposed for the T&C supply chain to systematically capture and share data in the supply chain network. The proposed framework demonstrates the applicability of shared data infrastructure to traceability without a central authority and develops technology-based trust among the supply chain actors. It relies on no central authority, and has customized data privacy and accessibility rules, thus providing a unique opportunity, flexibility, and authority to all supply chain actors to trace their supply chains and create transparent and sustainable supply chain networks.
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| 3. |
- Akinbomi, Julius
(author)
-
Fermentative hydrogen and methane productions using membrane bioreactors
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The role of energy as a stimulant for economic growth and environmental sustainabilityof any nation has made the focus on green fuels, including fermentative hydrogen (bioH2) andmethane (bioCH4), to be a priority for the World’s policy makers. Nigeria, as the most populousAfrican country, with worsening energy crisis, can benefit from the introduction of the bioH2 andbioCH4 technologies into the country’s energy mix, since such technologies have the potential ofgenerating energy from organic wastes such as fruit waste.Fruit waste was studied in detail in this work because of its great economic andenvironmental potential, as large quantities of the wastes (10–65% of raw fruit) are generatedfrom fruit consumption and processing. Meanwhile, bioH2 and bioCH4 productions involvinganaerobic microorganisms in direct contact with organic wastes have been observed to result insubstrate and product inhibitions, which reduce the gas yields and limit the application of thetechnologies on an industrial scale. For example, in this study, the first experimental work todetermine the effects of hydraulic retention times and fruit mixing on bioH2 production fromsingle and mixed fruits revealed the highest cumulative bioH2 yield to be equivalent to 30% ofthe theoretical yield. However, combining the fermentation process with the application ofmembrane encapsulated cells and membrane separation techniques, respectively, could reducesubstrate and product inhibitions of the microorganisms. This study, therefore, focused on theapplication of membrane techniques to enhance the yields of bioH2 and bioCH4 productions fromthe organic wastes.The second experimental work which focused on reduction of substrate inhibition,involved the investigation of the effects of the PVDF membrane encapsulation techniques on thebioH2 and bioCH4 productions from nutrient media with limonene, myrcene, octanol and hexanalas fruit flavours. The results showed that membrane encapsulated cells produced bioCH4 fasterand lasted longer, compared to free cells in limonene. Also, about 60% membrane protectiveeffect against myrcene, octanol and hexanal inhibitions was obtained. Regarding bioH2production, membrane encapsulated cells, compared to free cells, produced higher average dailyyields of 94, 30 and 77% with hexanal, myrcene and octanol as flavours, respectively. The finalpart of the study, which was aimed at reducing product inhibition, involved the study of theeffects of membrane permeation of volatile fatty acids (VFAs) on the bioreactor hydrodynamicsin relation to bioH2 production. The investigation revealed that low transmembrane pressure of104Pa was required to achieve a 3L h-1m-2 critical flux with reversible fouling mainly due to cakelayer formation, and bioH2 production was also observed to restart after VFAs removal.The results from this study suggest that membrane-based techniques could improve bioH2and bioCH4 productions from fermentation media with substrate and product inhibitions.
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| 4. |
- Andersson, Roy
(author)
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Quality-driven logistics
- 2007
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Licentiate thesis (other academic/artistic)abstract
- The overall objective of this thesis is to describe and explain how different quality management philosophies can be combined in the supply/demand chain, in order to contribute to its resilience. The analysis is both quantitative and qualitative, based on theory and literature related to TQM, Lean, Agile and Six Sigma, one literature study and three case studies that were performed in companies. The studies are related to four research questions and are presented in four papers. The first research question focuses on similarities and differences between the quality management concepts TQM, Lean and Six Sigma. The findings were that TQM, Six Sigma and Lean have many similarities, but they differ in some areas. For examples Lean addresses process flow and waste, whereas Six Sigma addresses variation and design. The conclusion is that there is a lot to gain if organisations are able to combine these three concepts, as they are complementary. Two case studies and a literature survey supported the findings. The second research question focuses on outcomes in a logistics process if using quality management. The findings were that the quality management approach leads to risks being mitigated, managed and monitored and ensures a more effective, robust and flexible process, very much in line with the Agility philosophy. Solutions for quicker response to customers have also been introduced. The findings were supported by two case studies in seven companies. The third research question focuses on how prepared the transport- and logistics-oriented companies are for the application of quality concepts and quality management philosophy. The findings were that they can be described as being TQM-oriented. The companies do not consider Lean and Six Sigma to be future trends. Focus is on the customer, while they do not focus on variations or removing waste. The findings were supported by a case study in 24 companies. The fourth research question focuses on how quality concepts can contribute to risk control and resilience in an organisation. A combined Lean/Six Sigma approach by using Six Sigma framework and the last phase, Perfection, in the Lean concept, implies that the companies’ resilience, due to their strengthened ability to handle variability, risk management and agility, was improved. The findings were supported by two case studies in seven companies.
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| 5. |
- Andersson, Roy
(author)
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Supply chain resilience through quality management
- 2009
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Doctoral thesis (other academic/artistic)abstract
- The length and complexity of the supply chain tend to increase, rather than diminish, thereby making the supply chain riskier and less predictable and, hence, more vulnerable. At the same time, customers are becoming increasingly demanding. The challenge to businesses today is to create a resilient supply chain in order to manage and mitigate risk and vulnerability.The purpose of the thesis is to explore, describe and develop the use of a combined quality management philosophy in logistics processes in order to improve supply chain resilience. The findings are supported by six studies, which are presented here in six papers.The studies show that there is a lot to gain if organisations are able to combine quality management philosophies, as they are complementary to one another. TQM places its strongest emphasis on the commitment and involvement of all employees. Lean is a discipline that focuses on process speed and removal of waste in order to increase customer value. Six Sigma benefits from an added focus on variability and design of products/services and processes. It has been indicated that a combined quality management philosophy makes the logistics processes more reliable, flexible, agile and robust while reducing cost. The companies’ risk awareness has increased and their risk management has been improved, thanks to the Six Sigma training programmes and philosophy. Using a combined quality management philosophy, the speed of production could be increased, and the responsiveness and flexibility could be improved, which means quicker response to changes. It has also been indicated that a combined quality management philosophy improves the companies’ resilience, due to their increased agility and strengthened ability to handle variability and risk management. Quality management tools can be very effective in the companies’ efforts to control supply chain risk and to identify risk sources of variation, even outside the focal company. In Six Sigma projects, the root cause of variation is often found outside the focal companies, which requires more collaboration in the supply chain. However, if the companies that use a combined quality management philosophy intend to become more resilient, they must involve suppliers and customers more in their own processes and design products/services and processes together.Collaboration with the suppliers and customers and the notion of how to extend a combined quality management philosophy outside the focal company are of importance in order to make the whole supply chain resilient. This could lead to a problem, especially since the conditions for transport and logistics in regards to the application of quality methods and tools represent a large area, unexploited by the companies. On the other hand, Six Sigma has standardised training courses, and it has been demonstrated how a Six Sigma framework can enable collaboration across companies’ boundaries in the supply chain, with the use of Six Sigma training and the DMAIC-roadmap as a common platform. Even if a combined quality management philosophy is effective and efficient, the companies must re-invest in additional methods, tools and strategies to make the entire supply chain resilient. It could be this re-investment in risk prevention and mitigation solutions that enables faster process responsiveness, the establishment of a risk management culture by creating common values, culture and rules in the supply chain and the use of logistics strategies and methods.
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| 6. |
- Andersson, Ulf, 1985-
(author)
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Clinical reasoning among emergency medical service clinicians : An iterative and fragmented process involving the collaborative effort(s) of many
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Aim: The overall aim of the thesis was to generate knowledge and understanding of clinical reasoning in the context of EMS from the perspective of EMS clinicians.Method: Three different methodologies were employed to describe various aspects of clinical reasoning. In Study I, an integrative literature review was conducted to summarise the existing literature related to clinical reasoning in EMS. After conducting systematic searches and screening, 38 articles were identified and analysed through an inductive thematic analysis. Studies II and III were conducted as case studies within an EMS organisation to capture clinical reasoning as it takes place in the naturalistic environment. In total, 34 patient encounters were observed, and group and individual interviews were conducted with EMS clinicians and organisational representatives at various hierarchical levels within the EMS organization. The data were analysed through pattern matching and triangulation in a computerised software program for qualitative analysis. Study IV was conducted as a goal-directed task analysis which focused on what EMS clinicians need in terms of achieving situation awareness. An online survey was created and answered by 30 EMS subject matter experts, consisting of active EMS clinicians, academic teachers in specialist ambulance nursing programmes, and researchers in the field of EMS. The data were analysed using qualitative content analysis and descriptive statistics.Main results: Clinical reasoning in EMS is a continuously ongoing, iterative, and fragmented process. Information is gathered, analysed, and utilised at any given point during the mission. This information is then reasoned against various goals or instructions provided by the EMS organisation or what is perceived as the most suitable action by the EMS clinician. In the reasoning process, the clinicians take the patients’ and their relatives’ points of interest into account, striving to fulfil these. The clinical reasoning process continues after and between the missions well, and clinicians constantly evaluate their decisions and care provision for future improvement. Even if medical and caring interventions are the focus of clinical reasoning, this process involves the consideration of other aspects as well, such as logistics and safety for everyone present. Nevertheless, there seems to be a vague mandate for decision making among EMS clinicians in relation to other collaborative partners. Furthermore, organisational support for clinical reasoning and development is lacking, often due to economic limitations.Conclusion: This thesis contributes to the caring science field with an increased understanding of the complexity of clinical reasoning in EMS. EMS clinicians today need to rely on themselves or their partners to have sufficient knowledge or experience to handle the situation encountered and provide safe patient care. As the reasoning process involves more than the physical patient encounter, additional support is needed to inform clinicians in decisions related to logistics and safety. As the reasoning process involves more than the physical patient encounter, additional support is needed to inform clinicians in decisions related to logistics and safety. EMS clinicians today need to rely on themselves or their partner to have sufficient knowledge or experience to handle situations encountered and provide patient safe care.
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| 7. |
- Asadi, Milad, 1987-
(author)
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Graphene : a vision to the future of smart E-Textile application
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Smart textile is a term referring to the textiles that could interact with their environment, receiving input and giving output based on their applications. Among smart textiles, electrically driven smart textiles (E-textiles) are being produced by various methods and materials integrated with textile substances. Graphene is one of these compounds that could be integrated into the polymer or integrated into the textile materials such as fibres. Therefore, other elements could be doped or immobilised on the graphene nanosheets for a wider range of applications, such as catalytic and electrocatalytic systems. However, finding the most applicable and efficient method to integrate graphene into the textile fibres and further establishing a method for catalyst immobilisation are challenging and require focused research. Therefore, this doctoral thesis focused on the innovative concept of integration of graphene and immobilisation of iron nanoparticles on it. Evidence from the systematic experiments was gathered for the case of dip-coating of polyester textiles with graphene oxide dispersion and enhancing the electrostatic bonding between fibres and graphene oxide nanosheets. In the second step, systematic experiments were gathered for the case of immobilisation of an inorganic catalyst (zerovalent iron) on textile supports. The goal of this thesis is to establish the feasibility of a mild and applicable method for textile material supports, which requires low temperature and mild pH, and further fabrication of heterogeneous catalytic and electrocatalytic systems for wastewater treatment. Polyester was chosen as the textile support material for graphene oxide coating and catalyst immobilisation due to its availability and cost-effectiveness. The thesis has four distinct parts related to (a) Pre-surface-charge modification of the polyester for strong electrostatic bonding between polyester and graphene, (b) Design a continuous yarn coating system for mass production of graphene-coated conductive yarns, (c) Immobilisation of Fe0 on graphene-coated polyester textiles and optimising their feasibility in catalytic systems and (d) Design and prove the feasibility of knitting a fully textile-based reactor having two anodic and cathodic sections by using rGO-Fe0 yarns and stainless-steel multifilament yarns, respectively as a concept of electro-Fenton wastewater treatment. Diverse analytical and instrumental techniques were used to monitor the surface modification of the polyester textiles and conductivity of the resulting textiles; moreover, the electromechanical and electrothermal properties of the graphene-modified textiles were examined. Further, the efficiency of catalyst immobilisation, physio-chemical properties of the immobilised catalyst, and their catalytical activities in dye removal from the water was studied. Results showed that surface charge modification of polyester fabric with both chitosan and hexadecylpyridinium chloride (HDPC) gives the most homogeneous graphene coating, resulting in high conductivity and very good fastness. Furthermore, results from scanning electron microscope (SEM), Differential scanning calorimetry (DSC), and UV/Visible spectrophotometry prove the success of immobilisation of zerovalent iron on the graphene-modified textiles. The novelty of the research presented in this doctoral thesis is primarily attributed to the novelty of a hybrid graphene-catalyst immobilisation-grafting on polyester textile supports for wastewater treatment applications. The final concept of the thesis is to introduce the potential for assembling a fully textile-based reactor for Electro-Fenton wastewater treatments.
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| 8. |
- Aslanzadeh, Solmaz
(author)
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Pretreatment of cellulosic waste and high rate biogas production
- 2014
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Doctoral thesis (other academic/artistic)abstract
- The application of anaerobic digestion technology is growing worldwide, mainly because of its environmental benefits. Nevertheless, anaerobic degradation is a rather slow and sensitive process. One of the reasons is the recalcitrance nature of certain fractions of the substrate (e.g., lignocelluloses) used for microbial degradation; thus, the hydrolysis becomes the rate-limiting step. The other reason is that the degradation of organic matter is based on a highly dynamic, multi-step process of physicochemical and biochemical reactions. The reactions take place in a sequential and parallel way under symbiotic interrelation of a variety of anaerobic microorganisms, which all together make the process sensitive. The first stage of the decomposition of the organic matter is performed by fast growing (hydrolytic and acid forming) microorganisms, while in the second stage the organic acids produced are metabolized by the slow growing methanogens, which are more sensitive than the acidogens; thus, methanogenesis becomes the rate-limiting step. The first part of this work evaluates the effects of a pretreatment using an organic solvent, N-methylmorpholine-N-oxide (NMMO), on cellulose-based materials in order to overcome the challenge of biomass recalcitrance and to increase the rate of the hydrolysis. NMMO-pretreatment of straw separated from the cattle and horse manure resulted in increased methane yields, by 53% and 51%, respectively, in batch digestion tests. The same kind of pretreatment of the forest residues led to an increase by 141% in the methane production during the following batch digestion assays. The second part of this work evaluates the efficacy of a two-stage process to overcome the second challenge with methanogenesis as the rate-limiting step, by using CSTR (continuous stirred tank reactors) and UASB (up flow anaerobic sludge blanket) on a wide variety of different waste fractions in order to decrease the time needed for the digestion process. In the two-stage semi-continuous process, the NMMO-pretreatment of jeans increased the biogas yield due to a more efficient hydrolysis compared to that of the untreated jeans. The results indicated that a higher organic loading rate (OLR) and a lower retention time could be achieved if the material was easily degradable. Comparing the two-stage and the single-stage process, treating the municipal solid waste (MSW) and waste from several food processing industries (FPW), showed that the OLR could be increased from 2 gVS/l/d to 10 gVS/l /d, and at the same time the HRT could be decreased from 10 to 3 days, which is a significant improvement that could be beneficial from an industrial point of view. The conventional single stage, on the other hand, could only handle an OLR of 3 gVS/l/d and HRT of 7 days.
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| 9. |
- Axelson, Mats, et al.
(author)
-
Träkonstruktioner EK5 Materialegenskaper och dimensioneringsregler för balkar, pelare och förband
- 2011
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Book (other academic/artistic)abstract
- Standarden Eurokod 5 är gällande dimensioneringsstandard sedan januari 2011. Denna handbok innehåller en samling av formler och tabeller för materialegenskaper och dimensionering av träkonstruktioner enligt Eurokod 5. I skriften behandlas både brottkraven som ställs på bärande konstruktioner och funktionskraven såsom nedböjning. Spik- och skruvförband, dimensioneringsformler och minimikrav presenteras följt av en samling av praktiska övningar med lösningsförslag. Handboken framställdes i samarbete mellan Högskolan i Borås och SP Trätek.
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| 10. |
- Baghaei, Behnaz
(author)
-
Development of thermoplastic biocomposites based on aligned hybrid yarns for fast composite manufacturing
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The interest in natural fibres as reinforcement for composite materials has been steadily increasing due to their attractive mechanical properties and the possibility of making more eco-friendly materials. Currently, various alternatives are being introduced for commercial applications, as fibres such as hemp, jute and flax exhibit properties, which make them appropriate for structural composite components. Biocomposites offer reductions in weight and cost and have less reliance on foreign oil resources, making them attractive. Several investigations have revealed that the full utilisation of fibre mechanical properties in the final composites can be exploited, provided an aligned fibre orientation is chosen. In fact, a major challenge for natural fibre reinforced composites is to achieve high mechanical performance at competitive prices. The use of commingled/hybrid yarns is one of the more promising methods for manufacturing structural thermoplastic composites.Commingled yarns of thermoplastic and reinforcing fibres offer a potential for cost-effective production of composite parts, thanks to reduced applied pressures and impregnation times during processing. Besides economic advantages, there is also direct control over fibre placements and ease of handling of fibres in yarn process. The yarn technologies provide homogenous distribution of reinforcing fibre and matrix. Variation in natural fibre properties has been a major problem facing composite manufacturers, compared to carbon and glass fibres that have well-defined production processes. This issue can be addressed by regenerated cellulose fibres. These fibres can be reproduced easily with high surface evenness and even quality, making it possible to get consistent results, which is not possible with natural fibres. Combination of natural and regenerated cellulose fibre brings together the best of both materials. The end result is a product with superior properties, which could not be obtained by the individual components.This thesis describes the development of aligned hybrid yarns with low fibre twist, for high performance natural (hemp) and man-made (Lyocell) cellulose fibre-reinforced biocomposites, suitable for use in structural or semi-structural applications. The properties of composites in terms of fibre orientation, off-axis angle and alkali treatment were investigated, focusing on determining void%, water absorption, mechanical and thermo-mechanical properties. The results show that combining hemp and Lyocell in PLA composite leads to the reduction of moisture absorption and can improve the mechanical properties. The mechanical properties of the composites were highly affected by the fibre direction. The alkali treatment on hemp fibre improved the mechanical properties of the composites.
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