Fraunhofer Chalmers Research Centre for Industrial Mathematics
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Performance and filtration characteristics of floccular and aerobic granular sludge using dynamic membrane filtration
No full textModeling and finite element simulation of the bifunctional performance of a microporous structural battery electrolyte
No full textThe structural battery composite is an innovative solution for a light-weight storage of electrical energy. It is multifunctional since it carries mechanical loads and stores electrical energy simultaneously. Such multifunctional materials will become important for e.g. the electrification of vehicles since large weight-reductions can be gained. This innovation will contribute greatly to realizing the vision of a carbon-neutral circular economy.
Due to the infancy of this technology, the structural batteries still need to be developed further.
The main purpose of the project is to model and simulate the diffusive transport of lithium ions through the
structural battery electrolyte (SBE) between the structural battery electrodes in a laminar setup, and to simulate the SBE’s mechanical behaviour. The SBE is a microporous polymer matrix filled with a liquid electrolyte.
By generating an artificial SBE microstructure and performing some virtual material testing, it will become
possible to evaluate the effective multifunctional performance of the SBE for varying pore sizes.
The artificial SBE microstructure is generated by manipulating the stationary heat equation. It is possible to choose heat sources and heat sinks in a clever fashion in order to obtain the desired shape for the artificial
microstructure. The choice of heat sources and heat sinks is based on a periodic Voronoi tessellation that is
embedded in a solid unit cube. By letting the Voronoi edges be heat sources, and the Voronoi seeds be heat
sinks, an artificial microstructure which is microporous and bicontinuous is obtained after some modification
and post-processing of the temperature field.
The multifunctional performance of the SBE is evaluated by applying the theory of computational homogenization
on the artificial SBE microstructure which serves as a statistical volume element with the ability to
almost fully characterize the material’s heterogeneities. In particular, the weakly periodic boundary conditions
are used. The results from the virtual material testing indicate that the lower bound of the stiffness increases
for increasing volume fraction of polymer matrix, while the upper bound of the stiffness and the ionic conductivity decreases. Furthermore, the effective diffusivity seems to scale linearly with the volume fraction while the bounds of the effective stiffness seem to scale non-linearly. Although the goal of the project is to mimic the SBE in the structural battery, the end result is a quite general recipe on artificial microstructure generation. Nevertheless, this thesis paves the way for more rigorous artificial
SBE microstructure generation in the future
Driver Influence on Vehicle Track-Ability on Floating Bridges
No full textThe Norwegian highway route E39 consists of many different ferry connections,
which results in a travel time of 21 hours for a travel distance of 1100 km from
Kristiansand to Trondheim. The Norwegian government has therefore decided to
invest in new infrastructure, which would reduce the travel time to about half.
One of these solutions are to implement floating bridges. Floating bridges have the
capacity to cross large distances such as fjords, but would also introduce motion
to the vehicles driving upon it. Having waves and wind affecting the bridge, and
crosswind directly affecting the vehicle, makes it difficult to assess the problem using
existing theoretical methods. Therefore, a method to investigate how a moving road
surface will affect the vehicle and the driver needs to be developed in this project.
The study utilized a industry-grade motion driver-in-the-loop simulator. This report
describes how the method for testing these driving conditions was achieved and
assesses the validity of using such method. The conclusion was that the method of
evaluating the driver influence on track-ability on floating bridges is functional
Business Relationships and its Impact on Customer Requirements A Case Study at Volvo Group
No full textAs of January 1st, 2020, new regulations regarding sulphur emissions will be implemented, called IMO 2020. This implies that the limit for sulphur in fuel oils used in ships operating outside Emission Control Areas (ECAs) is decreased from 3.5 % to 0.5. A majority of today's shipping fleets use bunker oil. However, this fuel does not comply with the new regulation in terms of sulphur emissions. Therefore, the shipping lines are forced to act in order to comply with the new restrictions to avoid sanctions. There are three strategic options for the carriers in order to adapt, where the indications point to that the most widely used option will be a switch to LSMGO fuel. This fuel is more expensive than the fuel used today, and the container shipping industry alone could see a total of $15 billion in increased fuel costs yearly. This cost will ultimately be put on the customers. Because of this, Logistics Purchasing is interested in finding how specifications and requirements could be challenged or adjusted in order to decrease costs and to mitigate the additional cost that derives from IMO 2020.
The aim of this master thesis is to identify possibilities and hinders to adjust current specifications and/or requirements in order to reduce costs. This was achieved by examining the sourcing process together with an analysis of Logistics Purchasing’s current relationships with two container carriers in order to identify the characteristics of the relationships. To reach the aim of the thesis, interviews were carried out internally and externally. From the interviews, it was possible to identify the level of involvement, what interface, types of collaborations, as well as uncertainties that exists.
The thesis has shown that the relationships with the carriers are characterized by low involvement with a specified interface. It has also shown that the type of collaborations between Logistics Purchasing and the carriers differ to some extent, and that uncertainties exist. It has been identified that Logistics Purchasing could increase the price orientation by using more standardized specifications and requirements, resulting in increased competition among carriers. This could ultimately impact the price. Possibilities have also been identified in terms of having a different strategy towards the carriers. This would mean that Logistics Purchasing could have different levels of involvement with different carriers depending on the carriers’ unique capabilities and resources. This could create possibilities to benefit from low involvement relationships and optimize each transaction with carriers who economize through scale and scope, while high involvement relationships would focus on long term operational optimisations with carriers who economize through innovation. In a high involvement relationship, specifications and requirements could be created jointly in order to achieve mutual benefits, such as reduced total costs
Solving the Fisher Equation to Capture Tumour Behaviour for Patients with Low Grade Glioma
No full textLow Grade Glioma is a slow growing brain tumour, whose size is estimated using Magnetic Resonance Imaging and is treated with a combination of surgery, radiation and chemotherapy. However, cancer cells often remain after surgery leading to recurrence of the tumour and eventually death. To address this problem the Fisher equation has been considered, a partial differential equation describing how the cancer cell density changes over space and time. The Fisher equation can thus be fitted to patient data by comparing the tumour growth rate and the slope of the tumour interface, properties that is hypothesized to affect the survival time of the patients. The aim of this project is to simulate tumour growth to give additional informationaboutLowGradeGliomathatcannotbeestimateddirectlyfromMagnetic Resonance images, but requires mathematical modelling. To do this, tumour propertieshavebeenestimatedfromdataandstatisticallytestedtoinvestigatetheir potential effect on survival. Also, we have compared different methods of solving the Fisher equation and fitted the equation to data through parameter estimation techniques. The results show that two out of three investigated tumour properties have a significant effect on survival. The parameter estimation was successful and the different numerical methods for solving the Fisher equation yielded similar results for most cases. Additional information about the tumour was estimated from the Fisher equation, but the reliability of these results could be questioned. The main caveat is the simplicity of the Fisher equation and the small size of the patient data set. One solution could be to include the effect of surrounding tissue in the Fisher equation, but this requires accurate data containing many measurements for all patients. A second approach could therefore be to create a model using Non Linear Mixed Effect modelling, with the Fisher equation as the framework, in order to make the model more accurately capture the variation among patients