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Integration of BECCS to a CHP plant - A comparison between CCS technologies using HPC and MDEA/DEA blend by performing Aspen Plus simulations
(2023) Håkansson, Lina; Markovic, Branko; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Bernin, Diana; Rydberg, Tomas
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Characterisation of natural fibre composites using X-ray computer tomography aided engineering
(2023) Iversen, Marcus; Årmann, Anton; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Asp, Leif; Gutkin, Renaud
The incorporation of bio-based materials and biocomposites is a crucial component in the pursuit of climate neutrality. Volvo Cars has set a target to achieve climate neutrality by 2040, leading to a growing interest in the application of bio-based materials and biocomposites. This has stimulated research in the field of mechanical behaviour and modelling, using Computer Aided Engineering (CAE) tools. Today there is a lack of Finite Element (FE) and material models for biocomposites, in particular those made of natural fibres as they display a complex microstructure. Throughout the project three kenaf fibre reinforced composite samples are analysed and characterised. The complex microstructure is obtained from Computer Tomography (CT) scanning, which is a non-destructive method. X-ray computer tomography Aided Engineering (XAE) is used to characterise the nonlinear behaviour of natural fibre composites by creating a FE-model. The FE-model is used in a virtual tensile test and compared against a physical test to calibrate the material properties of the samples. FE-simulations of natural fibre composites based on detailed information of their microstructure lacks in the litterature. To the best of our knowledge, conducting it at the coupon level has not been attempted in research until this day. The results shows that the characterisation of the microstructure using CT-scanning is successful. Furthermore, the result shows that the XAE process, going from image data to creating a mesh and running a quasi-static FE analysis, is applicable to a natural fibre composite. Thereafter, virtual tests are correlated against the mechanical tests and the material calibration successfully captures the initial stiffness, the non-linearity and the peak load of the samples. Further, the response for different areal weights are successfully predicted using the calibrated mechanical properties
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Early Detection of Rare Events: Predicting Battery Cell Deviations
(2023) Boberg, Jesper; Segerlund, Anders; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Volpe, Giovanni; Johansson, Herman
Despite rigorous quality controls in battery cell production, the production process is still subject to quality deviations. These quality deviations; known as "rare events", initially act as passive quality deviations which may not affect the battery’s perfor mance. However, a passive quality deviation can transition into an active deviation that may give rise to behavioral issues in the battery cell at some point during its lifetime. An active quality deviation can cause the entire battery to misbehave and eventually fail. This thesis investigates the possibility of predicting these cell devia tions in car batteries. Better predictions of these events would avoid expensive and troublesome car failures and enable preventive car maintenance to solve the problem. In this report, different models are created and evaluated with the aim of preventing these deviations. The dataset is supplied by Volvo Cars and contains a large amount of data collected from Battery Electric Vehicles (BEVs), where the arguably largest challenge comes from the imbalance of the dataset. In addition to the modelling, the thesis includes a thorough data analysis with the aim of improving both the dataset itself and the data collection process at Volvo Cars. These deviations occur extremely rarely, making a relatively large amount of false positives difficult to avoid. The results show that a simple time series model can catch these deviations relatively well but also brings along a large number of false positives. A neural network is able to improve this significantly, still being able to catch the majority of the deviations while producing a lot fewer false positives.
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Kartläggning av icke värdeskapande aktiviteter under patientronden
(2023) Strand, Ellinor; Söderstedt, Erika; Chalmers tekniska högskola / Institutionen för teknikens ekonomi och organisation; Chalmers University of Technology / Department of Technology Management and Economics; Eriksson, Henrik; Apell, Petra
Patientronden är en gammal tradition inom svensk sjukvård. Rondens utformning och omfattning varierar mellan olika avdelningar, sjukhus och regioner, men flera undersökningar visar på att ronden på flera ställen är tidskrävande och ineffektiv och att detta direkt påverkar arbetsmiljön och arbetsbelastningen för personalen. Med en sjukvård som står inför allt större utmaningar med långa väntetider och överbeläggning av patienter samt underbemanning och utbrändhet hos personal finns ett behov av att effektivisera sjukvården. Syftet med denna rapport är att kartlägga rondprocessen och undersöka om det förekommer icke värdeskapande aktiviteter under patientronden och att, om sådana aktiviteter identifieras, även identifiera rotorsakerna till dessa aktiviteter och ge förslag till hur dessa kan elimineras för en effektivare vård med ett bättre flöde av patienter. Detta har gjorts genom en empirisk fallstudie med observationer och semistrukturerande intervjuer. Det har även genomförts regelbundna workshops med vårdavdelningarna som deltagit i projektet. Resultatet visar att det förekommer tre typer av icke värdeskapande aktiviteter på flera avdelningar. Trots att avdelningarna är olika och har olika specialiteter förekommer samma typ av slöserier på flera av avdelningarna. Dessa är väntan, outnyttjad kreativitet och överarbete/felaktiga processer. Slöserierna beror på störningar under ronden och att det saknas rutiner för ronden. Slutsatsen är att det förekommer icke värdeskapande aktiviteter under patientronden, men att det finns goda möjligheter att minska förekomsten av dessa icke värdeskapande aktiviteter. Utifrån en analys av orsakerna bakom dessa aktiviteter har tre förbättringsförslag tagits fram för att påbörja förbättringsarbetet. Dessa förslag har utformats för att främja motivation, öka delaktighet och underlättar kommunikation under rondarbetet och arbetsdagen. Denna studie kan förhoppningsvis bidra med en inblick i vilka orsaker som ligger bakom icke värdeskapande aktiviteter under ronden samt hur verksamheter inom svensk sjukvård kan arbeta för att minska de icke värdeskapande aktiviteterna och därmed öka patientrondens effektivitet.
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Creating documentation of a data visualization tool - A Study of Process and Contents Levels
(2023) Blomquist, Johanna; Vallbo, Sebastian; Chalmers tekniska högskola / Institutionen för teknikens ekonomi och organisation; Chalmers University of Technology / Department of Technology Management and Economics; Raharjo, Hendry; Raharjo, Hendry
The aim of the thesis is to create documentation on a data visualization tool for a case company. This documentation is used to allow more employees to learn how to visualize data themselves without having to go through the metrics team. The creation of the documentation is analyzed on both a process and content level, and the data is retrieved through a qualitative research design. On the process level, the focus is placed on factors for maximizing user engagement of the documentation. On the content level, the factors when visualizing the data desired are focused, in order to best document the process of doing so. The factors affecting the process level and the content level of the documentation are determined through analysis of relevant literature, secondary research and through qualitative interviews with relevant employees at the case company. For maximizing user engagement, it was found that the documentation has to primarily address the process of visualizing the data desired, both in regard to relevant literature as well as how to do it using the software, while also presenting itself in a way simple enough to make navigating the documentation more efficient and less time-consuming. For the factors to consider when visualizing the data desired, three criteria of selecting appropriate graphs were deemed most relevant and applied to the desired data accordingly. These criteria are the structure of the data sets, the intended use of the graph and the research question of the graph. Additionally, several data visualization guidelines found in literature were also considered when visualizing the data desired.