Fraunhofer Chalmers Research Centre for Industrial Mathematics
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Comparison of FBRM® and PIA for investigating the precipitation of Kraft lignin from aqueous solutions: Influence of salt type, concentration, temperature and pH
No full textCRISPR/Cas9 för introduktion av metaboliska vägar som möjliggör konsumtion av ättiksyra och xylos i Saccharomyces cerevisiae
No full textAbstract
CRISPR/Cas9 for introduction of metabolic pathways to
enable the consumption of acetic acid and xylose in
Saccharomyces cerevisiae
An alternative to fossil fuel is the usage of Saccharomyces cerevisiae in the process of
producing bioethanol from lignocellulosic biomass. However, S. cerevisiae can only
utilise around 70% of the sugars from lignocellulose to produce ethanol, rendering
the process inefficient. In order to increase the use of the sugars present in lignocellulosic
biomass, this study aimed to introduce metabolic pathways for both acetic
acid and xylose consumption in S. cerevisiae and analyse the effects of the modifications.
For the acetic acid consumption the adhE-gene was introduced whereas
for the xylose consumption three genes were introduced encoding xylose reductase
(XR), xylitole dehydrogenase (XDH), and xylulokinase (XK). The CRISPR/Cas9
genome editing system was transformed into the cells to introduce the two metabolic
pathways seperately in 12 strains of S. cerevisiae. The 12 strains included both laboratory
strains as well as industrial and wild type strains. To analyse the results the
three methods colony PCR, growth on solid selective media, and growth on liquid selective
media were used. All studied strains had successful transformations for both
pathways. On the other hand, the number of colonies varied between the different
strains. For both pathways, the laboratory strains generally had more transformed
colonies than the industrial and wild type strains. The lack of an integrated selection
marker when using CRISPR/Cas9 as the genome editing tool made the selection of
successfully engineered strains difficult. However, the results from growth in liquid
media and colony PCR indicated that the integration of the metabolic pathway was
successful for some of the strains. These results show that CRISPR/Cas9 is an useful
method for integrating new metabolic pathways in S. cerevisiae and with further
investigations the strains could provide important information in the development
of bioethanol production
Fate of Fuel Nitrogen in Chemical Looping Combustion: Influence of Homogeneous and Heterogeneous Reactions
No full textChemical looping combustion is a novel combustion technology that can be used to reduce CO2 emissions. However, with nitrogen containing fuels, NOx is expected to form. The mechanism of NOx formation and reduction due to fuel bound nitrogen in chemical looping combustion is not well established. As a step in understanding this mechanism, this thesis aims to investigate the influence of homogeneous, gasphase, reactions and heterogeneous, gas-solid, reactions causing NOx formation and reduction in chemical looping combustion. This was done by combining modelling and experimental endeavours. Gas-phase modelling of important homogeneous reactionswasperformedusingCHEMKIN.Furthermore,experimentswerecarriedout with thermal gravimetric analysis to study the important heterogeneous reactions, for which kinetics were derived. Activated, Norwegian ilmenite was used as oxygen carrier, as this is currently a bench-mark oxygen carrier. The proposed reaction pathway that the modelling work and the experiments are based on suggests that the NOx precursor NH3 can be catalytically decomposed to N2 or oxidised to NO by the oxygen carrier and that the formed NO can be reduced to N2, either by the catalyticreactionwithNH3 orbyoxidationofthereducedOC.Theresultsindicated that the heterogeneous reactions are of large importance and that the environment in chemical looping combustion cannot be modelled using only gas-phase chemistry. The main conclusions are that the heterogeneous reactions seem to dominate the NOx formation and reduction pathways and that NOx formation is larger than NOx reduction with respect to the heterogeneous reactions when utilising ilmenite as oxygen carrier
The challenges of supply market scanning A comparative study of supply market scanning for mature- and innovative technology in the automotive industry
No full textThe automotive industry is experiencing quick technological developments in areas such as
automation, connectivity and electromobility. This pushes large automotive OEMs to innovate and at
the same time provide their more mature technology to customers. This calls for scanning the market
to fulfil two parallel needs; both to find technical innovation in the market and to find the best
possible suppliers for mature segments. Literature on the area suggest that there might be different
challenges associated with scanning for innovative technology compared to mature technology, but no
studies have explicitly been done to compare the cases. This study therefore aim to investigate what
the different challenges are in supply market scanning for mature technology, compared to the
challenges associated with scanning for innovative technology.
The study follows a qualitative approach and is based on data collected through 19 interviews. The
interviews was divided into two categories, one targeting people in the organisation conducting
supply market scanning for mature technology and one targeting people conducting it for more
innovative technology.
The study finds that the challenges of supply market scanning for mature technology have similarities
to that of innovative technology, but that there are a few key differences. Supply market scanning for
mature technology mostly faces challenges related to areas of information gathering, knowledge and
experience, cross-functionality and network and storing and sharing information. Examples of
challenges are: purchasers must have a big network, not having guidelines of how to do supply market
scanning, making gathered information accessible to those of need it and not losing built up
experience. Regarding supply market scanning for innovative technology they also face the challenge
of making information accessible to those of need it, but more significantly they have different
challenges related to the areas mindset, legal aspects and specifications. These areas include
challenges about making the organisation open to scan for innovation despite the uncertainty it infer,
adapting legal documents to fit new types of suppliers and being able to specify innovative
technology.
The study discusses possible ways to address the identified challenges in order for large automotive
OEMs to improve their supply market scanning. The study does for example conclude that such
companies should reduce job rotation, introduce formal guidelines for how to conduct supply market
scanning, introduce a functional central database for supply market intelligence and change mindset in
regards to innovative technology
Manufacturing and characterisation of ultra-stiff composite material
No full textLighter materials are needed to decrease fuel consumption in the transport industry. Conventional carbon
fibre reinforced polymer composites have excellent stiffness-to-weight ratio, but are often discarded
due to brittleness. This Master’s thesis work investigates a new concept of carbon fibre reinforced
polymer composite material, which can prove to be lightweight, ultra-stiff, exceptionally strong and
easy to mass-produce. The new material consists of chopped ultra-thin tapes of very stiff carbon fibres
held together by polymer. The tape pieces are randomly distributed to give in-plane isotropy through
uniform orientation distribution. To allow for characterisation of this concept, the composite material
was manufactured by tapes falling randomly through a channel onto a step-wise rotating substrate to
build preforms, which were formed and cured by a heat press into plates. The plates were dissected
and characterised through thermal and chemical analysis, cross-section microscopy, mechanical testing
and fractography. The manufactured material shows great potential with a near isotropic behaviour,
average stiffness of around 65GPa and some measured tensile strengths in the vicinity of 500MPa.
The high tensile strength is found to depend on two competing fracture modes: tape pullout and fibre
tension failure. In conclusion, the material concept is promising and with a refined manufacturing
method we can soon see a new field of composite materials
What are the effects of AEBS on collision avoidance?
No full textAdvanced Emergency Braking System (AEBS) is an active safety system for Heavy Goods Vehicles (HGVs)
which aims to prevent rear-end collisions, i.e. when a vehicle drives into the rear of the vehicle in front. This
report investigates the performance of AEBS in Volvo HGVs, and describes under what circumstances the
system intervenes correctly and incorrectly respectively. Data from AEBS interventions by Volvo HGVs was
analysed, and patterns of the incorrect interventions were identified. These patterns were translated into code,
resulting in a program that automatically classifies the logged interventions as correct or incorrect. Different
variables were investigated for the correct and incorrect interventions separately, for the purpose of finding
factors that affect the performance of AEBS, i.e. under which circumstances the correct and the incorrect
interventions occur. The majority of the incorrect interventions were found to be due to stationary targets,
and only resulted in a short intervention with minor speed reduction. Therefore, it seems very unlikely that
the incorrect interventions would cause collisions. The majority of the interventions were found to be true,
and many of these interventions yielded a large speed reduction. Thus, AEBS interventions prevents many
collisions