| 1. |
- Backe, Björn
(författare)
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The need of condition monitoring to support simulations when predicting system availability of Functional Products
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, competition among product manufacturers has increased and many facebeing copied and thus losing their uniqueness. To differentiate on the market,new businesses, which extend the manufacturer’s responsibility throughsupporting and guaranteeing product performance, thus offering more value-creating activities, have received increasing interest.The concepts of Functional Products or Total Offers have emerged through the realization that it is tougher to compete with hardware products only. The Functional Products concept combines the development of hardware, software, services and management of operation, thereby integrating value-adding activities into complete offers. Offering a Functional Product is usually a lifecycle commitment (long-term business-to-business agreement) between the function provider and customer. In this type of business, agreed-upon availability is of importance, especially since the availability of a function can directly influence customers’ productivity. The provider and customer need to predict and evaluate the availability of the function, both in early phases of the product development process and continuously during operation throughout the contracted time. In this thesis, in paper A, a model for predicting and monitoring industrial system availability has been proposed to enable the provider of Functional Products to continuously evaluate, through simulation, the offer in terms of availability performance. The model integrates hardware, support system and monitoring system components and through this approach it is possible to utilize operational data in simulations for continuous prediction of availability during operation. Further, the results of paper B presented in this thesis may extend and improve the model proposed in paper A, if implemented. The results of paper B describe the addition of data stream forecasting to the data stream management fault detection system and have showed improved prediction capabilities. The approach to evaluate the availability in paper A may also be extended and improved through the results presented and demonstrated in paper C. In paper C, a software tool to predict system availability has been developed and demonstrated with data from a real industrial system. The results from the simulation demonstrated, together with the addition of the partitioned multi-objective risk method in paper C, provided an indication of what level of availability may be guaranteed for the product; thus, the approach may be used to compare the availability performance of different designs.
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| 2. |
- Bergqvist, Jonas, et al.
(författare)
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Sub-glass transition annealing enhances polymer solar cell performance
- 2014
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488. ; 2:17, s. 6146-6152
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Tidskriftsartikel (refereegranskat)abstract
- Thermal annealing of non-crystalline polymer: fullerene blends typically results in a drastic decrease in solar cell performance. In particular aggressive annealing above the glass transition temperature results in a detrimental coarsening of the blend nanostructure. We demonstrate that mild annealing below the glass transition temperature is a viable avenue to control the nanostructure of a non-crystalline thiophene-quinoxaline copolymer: fullerene blend. Direct imaging methods indicate that coarsening of the blend nanostructure can be avoided. However, a combination of absorption and luminescence spectroscopy reveals that local changes in the polymer conformation as well as limited fullerene aggregation are permitted to occur. As a result, we are able to optimise the solar cell performance evenly across different positions of the coated area, which is a necessary criterion for large-scale, high throughput production.
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| 3. |
- Diaz de Zerio Mendaza, Amaia, et al.
(författare)
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A fullerene alloy based photovoltaic blend with a glass transition temperature above 200 degrees C
- 2017
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 5:8, s. 4156-4162
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Tidskriftsartikel (refereegranskat)abstract
- Organic solar cells with a high degree of thermal stability require bulk-heterojunction blends that feature a high glass transition, which must occur considerably above the temperatures encountered during device fabrication and operation. Here, we demonstrate for the first time a polymer : fullerene blend with a glass transition temperature above 200 degrees C, which we determine by plasmonic nanospectroscopy. We achieve this strong tendency for glass formation through the use of an alloy of neat, unsubstituted C-60 and C-70, which we combine with the fluorothieno-benzodithiophene copolymer PTB7. A stable photovoltaic performance of PTB7 : C60 : C70 ternary blends is preserved despite annealing the active layer at up to 180 degrees C, which coincides with the onset of the glass transition. Rapid deterioration of the power conversion efficiency from initially above 5% only occurs upon exceeding the glass transition temperature of 224 degrees C of the ternary blend.
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