Fraunhofer Chalmers Research Centre for Industrial Mathematics
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Evaluation of emerging additive technologies for circuit board manufacturing
No full textThis thesis is focused on introduction of the state-of-the-art additive manufacturing process for circuit
board manufacturing in the development process. Project was carried out at Saab AB during 2018 and is
done in collaboration with the department for Industrial and Materials Science at Chalmers.
Focus of the thesis is to evaluate the possibilities and limitations of the recently developed
manufacturing technology, that allows for additive manufacturing of a Printed Circuit Board (PCB). The
technology was developed and launched by Nano Dimensions Ltd in the autumn of 2017. The additive
manufacturing technology used is based on modified material jetting process that utilizes an ink
containing silver or copper nano-powder in one printing head, and dielectric ink in other. This allows
for simultaneous printing of both materials.
After printing, green part is cured at elevated temperature in order to sinter metal nano-powder and cure
dielectric material. This is done by exposure to light from a photonic curing lamp after each layer is
deposited. This allows to produce complex two- and three- dimensional circuit boards, providing the
possibility to significantly speed-up process of PCBs development and prototyping. It also allows for
manufacturing 3D PCBs, not possible with the conventional technologies.
Focus is on the evaluation of the performance of the PCBs, made by new technology, extensive
characterisation of the microstructure of the PCBs, as well as defects and flaws that can affect its
applicability. The results were used to estimate applicability of this technology at Saab. Product
Lifecycle (PLC) for the PCBs made by this technology was evaluated as well.
Thesis also covers development of a method for evaluation of the new processes for PCB development
following lean testing and qualitative methodology. While including stakeholders in the process and
managing risks, it also discusses current state of additive manufacturing of electronics. For this purpose,
an evaluation board was developed and printed using the new process. Unfortunately, the board broke
during assembly, but material testing and inspections have given insights into the current state of PCB
3D-Printing.
Additive manufacturing of circuits and especially PCBs stand to develop rapidly over the coming years.
Even at their current stage they allow to speed up development and allow for quick production of small
series for production. Current limitations in additive processes limits its implementations but allows for
rapid prototyping of low- to mid- frequency circuits. The technology shows promising results and
potential to remove logistic bottlenecks, reduce waste and reduce the need for end of life purchase of
components
Fabrication of double-sided Fresnel zone plates and absolute measurements of their diffraction efficiency in an X-ray-tube-based setup
No full textDiffractive lenses for X-rays, so-called Fresnel zone plates (FZPs), are used as focusing elements in X-ray imaging applications in synchrotrons all over the world. One of the main characteristics of FZPs is their diffraction efficiency. Measurements of the absolute diffraction efficiency as a function of the X-ray energy can reliably be done using synchrotron radiation, but require beamtime at synchrotrons which is not available on a routine basis.
Here, the design, construction and characterization of an in-lab X-ray-tube-based setup for measuring the absolute diffraction efficiency of single- and double-sided FZPs is presented. The broad spectrum from the Xray tube is monochromatized using a set of copper- and nickel filters, giving an approximate X-ray energy of 8.4 keV; the spectrum is simulated and confirmed through spectrometer measurements. Single- and double-sided line-doubled Fresnel zone plates with different characteristics have been fabricated and measured using the setup, yielding absolute diffraction efficiencies of up to 6.4%. Diffraction efficiency maps, showing the spatial distribution of the diffraction efficiency, have been obtained for each zone plate. The measurements have given important information regarding issues with the fabrication process related to the alignment between the two halves of double-sided zone plates, and these issues have been investigated further. Finally, measurements have been performed where the misalignment in double-sided zone plates has been determined by employing a functionality of the setup where the measured zone plates can be tilted around two different axes
Hydrodynamic modelling of microplastic transport - A case study on microplastics from traffic emissions in the Göta River
No full textConcrete change: Exploring the effects of scaling up the use of alternative binders to reduce the climate impact from concrete
No full textThis thesis explores the potential of using alternative binders to replace cement clinker on a European scale in order to reduce the carbon dioxide emissions associated with concrete/ cement. Numerous studies highlight the importance of increasing the replacement ratio to meet international environmental goals [1]. However, little advancement has been made with respect to describing how to achieve these replacement goals.
This thesis work is focused on estimating the resource base, and the regional availability, of two conventional alternative binders, fly ash and blast furnace slag, in the EU. The availability of fly ash was estimated based on existing coal-fired power plants block net capacity. The blast furnace slag resource base estimated based on the existing and projected capacity of EU blast furnaces.
Further, the thesis, through scenario analysis, explore how the availability of alternative binders may change over time as existing capital stock in the power and steel industries are phased out. The scenarios were assessed using simulations from Matlab and further analysed with a software for spatial analysis. The results show that in the short term (5-10 years) it is possible, in most EU regions, to meet the demand for conventional alternate binders. In the long term (10-30 years), however, it will not be possible to fulfil a sufficient replacement in all European regions using only these two alternative binders. These finding confirms the importance of increasing the efforts to develop other measures to reduce the climate impact from concrete and cement, including increased use of lesser-known binders.
This study can hopefully encourage further researcher aimed at developing: a better understanding of the availability of other alternative binders, of processing techniques and of means to distribute them, so that the environmental goals in the concrete and cement industries may be achieved
INVESTIGATION AND ASSESSMENT OF PLUVIAL FLOOD MODELLING TOOLS IN URBAN AREAS - A RECOMMENDATION FOR FLOOD MANAGEMENT EXEMPLIFIED BY THE CATCHMENT AREA LINNÉSTADEN IN THE CITY OF GOTHENBURG IN SWEDEN
No full textCondition monitoring system for wind turbines - based on deep autoencoders
No full textWind turbines consist of many mechanical, electrical and hydraulic components. Failures in any of these can lead to high financial loss, both as actual repair costs and from lost production time. Often, failures do not occur instantaneously but rather as a consequence of sequential degrading. Therefore, many failures can be detected in advance using so-called condition monitoring systems. Through their supervisory control and data acquisition system, modern wind turbines store information about their operating state. Among other things, signals such as produced power, wind speed, and various component temperatures are recorded. In this thesis, a condition monitoring system that leverages this data is developed. The system is based on deep autoencoders, a type of neural network that learns to reconstruct its input data. By training an autoencoder on data from a healthy wind turbine it can learn the dependencies between different SCADA signals under normal conditions. If it then gives a poor reconstruction for new data, it is likely that something has changed in the internal dynamics of the wind turbine which could indicate a degraded component.
Previously, many similar systems have been developed. These have shown good results and detected multiple component failures up to months in advance. However, they usually only monitor one component at a time and are therefore not able to provide a complete condition monitoring system. Autoencoders, which do not suffer this problem, have also been investigated but not at a larger scale.
In this thesis, a relatively large, labeled dataset was utilized. With this data, the efficiency of condition monitoring systems based on autoencoders was tested on a variety of real faults. Moreover, the influence of various properties of the autoencoder was investigated. The results of the investigation showed that an autoencoder based condition monitoring system is capable of detecting a variety of failures in wind turbines. Finally, suggestions for future developments are discussed in the thesis
Agile project health indicators Project/Project portfolio Health indicators, frameworks and methods in agile projects.
No full textIncreased amount of complexity in the development of software projects have created the need for new non-traditional methods to run and organize projects. Agile is helping software companies to manage the complexity in their projects and teams to work more effectively towards effective project delivery. However, this methodology also brings uncertainties regarding the ways of working and there is a need for further clarifications and explorations in order to strive towards best practice. Finding accurate ways to ongoing measure the “health” of a project is one central aspect of this. Theory suggests that in order to work agile, one should decrease administrative work in order to help the project have an easy flow. However, the need to still measure end results on projects, is making companies adopt project management methods to work more agile. Having measurements will not only steer the projects towards plan, but it will also help to make more informed predictions of future outcomes. The aim of this master thesis is to suggest what kind of agile Key Performance Indicators are needed in order to measure the health of a project. A total of thirty-four interviews were conducted at different managerial levels in a software company in order to understand their ways of working with project management and agile. Data analysis identified current challenges and expectations for the future. Five different KPI are suggested and those are a combination of agile and non-agile project measurements. In this study, it was found out that the agile adoption in projects and project portfolio is very immature. There are still tension and uncertainties on how to work in agile, certain processes such as the measurements of projects need to be aligned to how agile works and the way it will work in the specific context. Measurements are good to predict the future, however if there is not a commitment from all the levels in the organization, these will not add any value to the projects. Hence commitment, transparency and collaboration among all the levels and in projects is key to have project success
