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  • 2501.
    Ahlin, Rikard
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Brinck, Viktor
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Klimatkalkylering2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a study on the climate impacts associated with the construction of railway bridges in order to develop key performance indicators such as operation, material and amounts to effectively reduce greenhouse gas emissions. The basis of the study has been work in Trafikverkets tool klimatkalkyl 2.0. It has been reviewed on the basis of ease of use and accuracy of input data and emission conversion factors. That’s because we wanted to see the difference between the model and a unique project. What was different and why?

    This study has concluded that without some care and work in klimatkalkyl 2.0 is a risk of incorrect results. In addition the study demonstrated questionable defaults for significant items. In addition to these results the study found that the most significant parts of the unique projects emissions is reducing the amount of steel and concrete and to find suppliers who can demonstrate low emission factors. With relatively simple measures could the unique projects total carbon emissions be reduced by almost 20%

  • 2502.
    Ahlin Wigardt, Oliver
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Deep Green, en jämförande analys2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Marine Energy has a great potential to extract energy in a relatively environmentally stable order from e.g. wind, waves and streams. Prototypes and power plants to extract energy from tidal streams have gotten quite popular the last 10 years, none the less because of the international environmental agreements. Minesto is a business that’s developing a tidal power plant called Deep Green that has a very unique design, and has been analysed and compared with two other relevant competitive tidal power plants, DeltaStream and Seagen S. This study has focused on the most common designs and variation by transmission, foundation, installation, strategy for maintenance and repairs, control and grid connections, to in a more structured way explain and introduce the three tidal power plants.

    Deep Green is a so called tidal kite. The tidal kite consists of a wing with nacelle and a turbine, and the unit is mounted to the seabed with a tether. Deep Green starts to move forward when the tide flows over the wing, due to the lift force, in a 8 shaped trajectory. The power plant reaches its max power extraction of 0,5 MW in tides from 1,4 m/s.

    DeltaStream and Seagen S are both tidal power plants with horizontally mounted turbines, by the same principle as wind power plants but design for underwater use. DeltaStream and Seagen S are producing 1,2 MW and 1,2MW – 2,0MW in tides from 3,1 m/s and 2,5 m/s, respectively.

    The comparing analysis shows that Deep Green has the greatest potential and was the best in 8 out of 18 points The analysis was compiled and was ranked through the points 1-3, with respect to characteristics relative to each other where the power plant with the best characteristic in one row got 3 points and the least good characteristic got 1 point. Is any information missing is 1 point given and equivalent properties get 2 or 1 point depending on the property. This compilation gave Deep Green 42 points, Seagen S 36 points and DeltaStream 34 points.

  • 2503.
    Ahlinder, Astrid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Fuoco, Tiziana
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Medical grade polylactide, copolyesters and polydioxanone: Rheological properties and melt stability2018In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 72, p. 214-222Article in journal (Refereed)
    Abstract [en]

    Rheological measurements have shown that lactide-based copolymers with L-lactide content between 50 and 100 mol% with varying comonomers, as well as polydioxanone (PDX), can be used in additive manufacturing analogously to poly(L-lactide) (PLLA) if their melt behaviour are balanced. The results indicate that copolymers can be melt processed if the temperature is adjusted according to the melting point, and parameters such as the speed are tuned to conteract the elastic response. Small amplitude oscillatory shear (SAOS) rheology, thermal and chemical characterisation allowed us to map the combined effect of temperature and frequency on the behaviour of six degradable polymers and their melt stability. Values of complex viscosity and Tan delta obtained through nine time sweeps by varying temperature and frequency showed that the molecular structure and the number of methylene units influenced the results, copolymers of L-lactide with D-Lactide (PDLLA) or glycolide (PLGA) had an increased elastic response, while copolymers with trimethylene carbonate (PLATMC) or epsilon-caprolactone (PCLA) had a more viscous behaviour than PLLA, with respect to their relative melting points. PDLLA and PLGA require an increased temperature or lower speed when processed, while PLATMC and PCLA can be used at a lower temperature and/or higher speed than PLLA. PDX showed an increased viscosity compared to PLLA but a similar melt behaviour. Negligible chain degradation were observed, apart from PLGA.

  • 2504.
    Ahlinder, Kristina
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Development of a Folding Boat Anchor2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report is the result from a Master of Science Thesis work at the Royal Institute of Technology, and is executed by technology student Kristina Ahlinder for the behalf of Design Company Top Notch Design AB. Top Notch Design wants to expand their range of marine products and look in to the market of boat anchors. The aim of the project is to develop an anchor for small leisure boats for the Swedish market with focus on usability and safety. A detailed informational study was executed at the beginning of the project. To collect information regarding how potential users experience current anchors on the market, a user test and a digital questionnaire was done. Through the questionnaire, the user test, requirements from the company and the informational study a criteria specification was made. Some of the criteria were that it should be an easy to stow day anchor designed for leisure boats up to 27 feet and have a maximal weight of 8 kg. Other important criteria were good usability and innovative and interesting design. The ideation stage of the project was mainly based upon brainstorming sessions. 11 concepts were sketched and prototyped in paper and wood. Ten of the concepts were manufactured in small-scale and welded together in steel, in order to evaluate the functionality. The anchors were dragged in a sandbox, and the drag-force was measured with a nanometer. The anchor that performed best in the drag test was a kind of foldable plow anchor. This is the concept that was chosen to be developed.The anchor was further developed and tested before being modeled in the CAD-program SolidWorks. The final design consists of a fluke and a shaft connected by a joint, and a handle for usability, ease of recovery and for getting it in the right angle on the seafloor. The anchor has an automatic locking mechanism in the joint, and rubber details. The anchor’s material is mainly aluminum and weighs 3.8 kilos and has a length of 48 centimeters.The anchor fulfills the criteria specification and most of the preferences and according to calculations the joint will hold for forces higher than 2000 N. The anchor will, according to calculations, have an approximate selling price of slightly over 500 SEK. According to feedback given by potential users, 40 % has a good impression of the anchor and 26 % could imagine buying it. The outcome is a new and innovation type of anchor that suits the modern small-boat owner. The anchor has to be tested in full scale with the correct materials to fully be evaluated. The anchor would contribute to the conservative marine market. The anchor would be a brave and interesting addition to the current anchor market, as well as to TND’s current marine products. 

  • 2505.
    Ahlinder, Kristina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Dahlkvist, Jessica
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Bidragande konceptarbete inför lanseringen av den optiska sensorn RailEye för bekämpning av spårhalka2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is a further development of RailEye, a development that is able to, by optics, detect where the train track is slippery. The problem is based on the slippery layer that is formed when leaves and moisture interact during cold temperature conditions, making it difficult for trains to maneuver. RailEye has been developed as a co-operation between Stockholm Public Transport (SL) and The Royal Institute of Technology (KTH), and was in the thesis prelude in need of further development. RailEye has a complete function, but requires a comprehensive analysis and plan for how it would work in practice. The work has focused on an examination of the slippery layer problem, its origins and consequences, and also the RailEye and its function. This has been achieved through literature studies, interviews and tests with the RailEye. This work has also resulted in a production of amounting solution for the RailEye on Roslagsbanan. Specifications for the mounting solution have been constructed. A plan to track RailEye’s signal system have also been developed with the help of a survey of Roslagsbanan’s and other traffic companies’ signal systems. A cube-like container for RailEye was designed. The container is fastened down by a fixed casing, which in turn is fastened up at the braking device on Roslagbanan’s motor- and manoeuvre wagon. Tests with RailEye showed that the shapes tested of the enclosure of the mounting, which emanates from the RailEye optics, does not affect the measurements of thesignals.When RailEye is mounted on the train it is required, for the signal measurements to be as reliable as possible, that the software uses information from both RailEye and weather stations. The telematic network TETRA (Terrestrial Trunked Radio) can be used to transfer information between RailEye, drivers, control center and the weather stations that must be placed along the rails. Using the predicting knowledge about the slippery locations on the track, the driver can adjust the speed and avoid delays. The mounting solution that is designed complies with the specifications in an acceptable way, both requirements and preferences. However, there remains much work before the RailEye can be presented as a complete concept for stakeholders.

  • 2506.
    Ahlinder, Ludvig
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Eriksson, Anders
    KTH, School of Information and Communication Technology (ICT).
    Accelerating Adoption of IPv62011Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    It has long been known that the number of unique IPv4-addresses would be exhausted because of the rapid expansion of the Internet and because countries such as China and India are becoming more and more connected to the rest of the world.

    IPv6 is a new version of the Internet Protocol which is supposed to succeed the old version, IPv4, in providing more addresses and new services. The biggest challenge of information and communication technology (ICT) today is to transition from IPv4 to IPv6. The purpose of this thesis is to accelerate the adoption of IPv6 by highlighting the benefits of it compared to IPv4.

    Although the need for more IP-addresses is the most urgent incentive for the transition to IPv6, other factors also exist. IPv6 offers many improvements to IPv4 which are necessary for the continued expansion of Internet-based applications and services.

    Some argue that we do not need to transition to IPv6 as the problems with IPv4, mainly the addressshortage, can be solved in other ways. One of the methods of doing this is by extending the use of Network Address Translators (NATs), but the majority of experts and specialists believe that NATs should not be seen as a long-term solution.

    Another difficulty with the new protocol is explaining its benefits and areas of use to both the business world and the public. Understanding these benefits are necessary in order create awareness of these benefits, thus to accelerating the adoption of IPv6. This thesis aims to explain the incentives for both businesses and the public to adopt IPv6.

  • 2507.
    AHLINDER, LUDVIG
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    LINDAHL, CARL
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    Areas of complexity in a reverse merger: An exploratory study regarding the complexity of theintegration process in a reverse merger2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mergers and acquisitions are common business practices and a large amount of studies point to the complexity of these endeavors and the difficulty of executing them successfully. Different kinds of mergers and acquisitions exist and one of the most uncommon forms is referred to as the reverse merger.

    The reverse merger is unusual in the sense that the acquiring company conforms to the ways and culture of the target company. Being such a rare event, little previous research regarding the reverse merger, and specifically the integration process of such an acquisition, exist. As a result, further enquiry was deemed necessary, which is why the purpose of this study is to explore said integration and identify areas of complexity in this process.

    In order to identify areas of complexity, the authors conducted a case study at a company who recently had partaken in an acquisition intended to be a reverse merger. The majority of the data was collected through in depth interviews on site as well as participatory observations.

    The findings in this study indicate three different areas of complexity: lack of cultural awareness, lack of planning as well as lack of communication. These three areas are intertwined and it is suggested that they are accounted for when pursuing a reverse merger. In addition, the findings of this study can be used as a foundation for future research.

     

  • 2508.
    Ahlinder, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Grass, Emil
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Construction Management: Risker och möjligheter för byggherrar2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Traditional and well established project delivery methods have during an extended time been used in the construction sector. During the last decades, usage of alternative process methods and organizational structures has increased within the Swedish construction sector. Thus, the process of choosing a project delivery method is getting more complex. Clients are benefitted from having good knowledge about different ways of operating construction projects. Clients’ aim for construction projects with low level of risk, at the same time the project should be efficient in terms of costs, time and quality. The outcome of a project is highly dependent on decisions being taken early in the process, though the possibility of risk-minimization and changes decreases over time. Therefore, one of the most important decisions for clients is the choice of project delivery method. Construction Management (CM) is one of the alternative project delivery methods that have increased in usage within the Swedish construction and real estate market. Consequently, clients have one additional project delivery method to evaluate in aspects of what risks and possibilities it would entail to the project. This study evaluates what risks and possibilities CM-projects have in relation to other methods and identifies when the project delivery method is most suitable to use. Further, the study examines the level of knowledge concerning CM among different actors within the Swedish construction sector. The purpose of this study is to increase the knowledge of the project delivery method and to suggest possible changes in the way CM is used.The study comprises a qualitative interview based method where a wide spread of actors from the Swedish construction and real estate market are participating. The result is founded upon the perceptions, experiences and reflections the participating actors have expressed. The result of this study shows that CM can be used in all types of projects, where the benefits of the delivery method are best used in complex projects with high levels of risk and uncertainty. The use of CM could lead to shorter project time, lower price and give the client possibilities of cost effective changes. However, the project risk and responsibility is to a greater extent held by the client. The respondents expressed a difference about the contractual risk levels and the levels based upon experience from project results, which makes it hard to evaluate if CM relates to a higher or lower degree of risk in comparison to the traditional delivery methods.    A lot of possible changes could be implemented in the way CM-projects are executed to adapt more to the clients’ needs and thereby increase the demand of the project delivery method. These changes contain modified contracts between consultants and clients to move parts of the risk to the CM-organization that holds the project management. Further changes in how the consultant fees are charged and how the warranties are handled could decrease the clients´ concerns with CM-projects.

  • 2509.
    Ahlklo, Yrr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Lind, Carin
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    E, S or G? A study of ESG score and financial performance2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sustainability is not a new concept to the financial markets, but its popularity and wider use have increased as people have grown more concerned about the future of this planet. However, the relationship between sustainable investments and financial performance is not clear. One of the most used measures of sustainability is the concept of ESG score, where E, S and G stand for environmental, social and governance. In this study, we investigate the relationship between ESG score and financial performance, both market and accounting based. We also separate the score into its individual parts E, S, and G, and try to distinguish which factor has the strongest relation to financial performance. To evaluate the relationship, a regression analysis was performed on a sample of Nordic stocks and the Sustainalytics ESG rank. Our findings concluded no significant relationship between ESG score and financial performance, neither market nor accounting based. The environmental factor (E) showed the strongest relation to financial performance, however slightly negative and only significant to one dependent variable out of three. Our results indicate that based on the ESG score used in this study, no conclusions can be drawn about financial performance. Since our research does not indicate a significant relationship, our recommendation is to invest in the highest ESG ranked stock in case of choosing between two otherwise similar stocks.

  • 2510.
    AHLKLO, YRR
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    LIND, CARIN
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    E, S or G? A study of ESG scoreand financial performance2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sustainability is not a new concept to the financial markets, but its popularity and wider use have increased as people have grown more concerned about the future of this planet. However, the relationship between sustainable investments and financial performance is not clear. One of the most used measures of sustainability is the concept of ESG score, where E, S and G stand for environmental, social and governance. In this study, we investigate the relationship between ESG score and financial performance, both market and accounting based. We also separate the score into its individual parts E, S, and G, and try to distinguish which factor has the strongest relation to financial performance. To evaluate the relationship, a regression analysis was performed on a sample of Nordic stocks and the Sustainalytics ESG rank. Our findings concluded no significant relationship between ESG score and financial performance, neither market nor accounting based. The environmental factor (E) showed the strongest relation to financial performance, however slightly negative and only significant to one dependent variable out of three. Our results indicate that based on the ESG score used in this study, no conclusions can be drawn about financial performance. Since our research does not indicate a significant relationship, our recommendation is to invest in the highest ESG ranked stock in case of choosing between two otherwise similar stocks.

  • 2511.
    Ahlklo, Yrr
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Lind, Carin
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Modellering och kundprocessanalys av kösystem på Vapiano Sturegatan2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this Bachelorthesis, the queuing system of Vapiano Sturegatan has been analysed. The customers of the restaurant experience long waiting times during lunchtime, which is a problem Vapiano Sturegatan  recognises. The purpose of this report is to suggest and analyse possible improvements of the queueing system in order to reduce this problem.

    The current queuing system was approximated with markovian queuing models. Both an M/M/2-and an M/M/8-approach were considered, which of the M/M/2-model was deemed most reliable. The expected time in the system was calculated for different modications of Vapiano Sturegatan's current queuing system setup. They led to the conclusion that adding capacity to every serving station would be the best improvement to their current system, instead of adding an extra station. Furthermore, other queuing systems are considered and analysed from a customer process perspective. To improve the flow of customers in the restaurant, this report suggests an electronic queuing system. As long as the suggested system is implemented with careful planning and evaluation, the advantages of the electronic system exceed the benefit of simplicity of the current queuing system.

    This thesis will be delivered to Vapiano Sturegatan. The authors hope that the results can beneficial in the planning of future restaurants and changes of the queuing system.

  • 2512.
    Ahlman, Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics.
    A study of turbulence and scalar mixing in a wall-jet using direct numerical simulation2006Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Direct numerical simulation is used to study the dynamics and mixing in a turbulent plane wall-jet. The investigation is undertaken in order to extend the knowledge base of the influence of the wall on turbulent dynamics and mixing. The mixing statistics produced can also be used to evaluate and develop models for mixing and combustion. In order to perform the simulations, a numerical code was developed. The code employs compact finite difference schemes, of high order, for spatial integration, and a low-storage Runge-Kutta method for the temporal integration. In the simulations performed the inlet based Reynolds and Mach numbers of the wall jet were Re = 2000 and M=0.5, respectively. Above the jet a constant coflow of 10% of the inlet jet velocity was applied. A passive scalar was added at the inlet of the jet, in a non-premixed manner, enabling an investigation of the wall-jet mixing as well as the dynamics. The mean development and the respective self-similarity of the inner and outer shear layers were studied. Comparisons of properties in the shear layers of different character were performed by applying inner and outer scaling. The characteristics of the wall-jet was compared to what has been observed in other canonical shear flows. In the inner part of the jet, 0 ≤ y+ ≤ 13, the wall-jet was found to closely resemble a zero pressure gradient boundary layer. The outer layer was found to resemble a free plane jet. The downstream growth rate of the scalar was approximately equal to that of the streamwise velocity, in terms of the growth rate of the half-width. The scalar fluxes in the streamwise and wall-normal direction were found to be of comparable magnitude.

  • 2513.
    Ahlman, Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Numerical studies of turbulent wall-jets for mixing and combustion applications2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Direct numerical simulation is used to study turbulent plane wall-jets. The investigation is aimed at studying dynamics, mixing and reactions in wall bounded flows. The produced mixing statistics can be used to evaluate and develop models for mixing and combustion. An aim has also been to develop a simulation method that can be extended to simulate realistic combustion including significant heat release. The numerical code used in the simulations employs a high order compact finite difference scheme for spatial integration, and a low-storage Runge-Kutta method for the temporal integration. In the simulations the inlet based Reynolds and Mach numbers of the wall-jet are Re = 2000 and M=0.5 respectively, and above the jet a constant coflow of 10% of the inlet jet velocity is applied. The development of an isothermal wall-jet including passive scalar mixing is studied and the characteristics of the wall-jet are compared to observations of other canonical shear flows. In the near-wall region the jet resembles a zero pressure gradient boundary layer, while in the outer layer it resembles a plane jet. The scalar fluxes in the streamwise and wall-normal direction are of comparable magnitude. In order to study effects of density differences, two non-isothermal wall-jets are simulated and compared to the isothermal jet results. In the non-isothermal cases the jet is either warm and propagating in a cold surrounding or vice versa. The turbulence structures and the range of scales are affected by the density variation. The warm jet contains the largest range of scales and the cold the smallest. The differences can be explained by the varying friction Reynolds number. Conventional wall scaling fails due to the varying density. An improved collapse in the inner layer can be achieved by applying a semi-local scaling. The turbulent Schmidt and Prandtl number vary significantly only in the near-wall layer and in a small region below the jet center. A wall-jet including a single reaction between a fuel and an oxidizer is also simulated. The reactants are injected separately at the inlet and the reaction time scale is of the same order as the convection time scale and independent of the temperature. The reaction occurs in thin reaction zones convoluted by high intensity velocity fluctuations.

  • 2514.
    Ahlman, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Brethouwer, Geert
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Johansson, Arne
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    A numerical method for simulation of turbulence and mixing in a compressible wall-jet2007Report (Other academic)
  • 2515.
    Ahlman, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Brethouwer, Geert
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Johansson, Arne
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Direct numerical simulation of a plane turbulent wall-jet including scalar mixing2007In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 19, no 6, p. 065102-Article in journal (Refereed)
    Abstract [en]

    Direct numerical simulation is used to study a turbulent plane wall-jet including the mixing of a passive scalar. The Reynolds and Mach numbers at the inlet are Re=2000 and M=0.5, respectively, and a constant coflow of 10% of the inlet jet velocity is used. The passive scalar is added at the inlet enabling an investigation of the wall-jet mixing. The self-similarity of the inner and outer shear layers is studied by applying inner and outer scaling. The characteristics of the wall-jet are compared to what is reported for other canonical shear flows. In the inner part, the wall-jet is found to closely resemble a zero pressure gradient boundary layer, and the outer layer is found to resemble a free plane jet. The downstream growth rate of the scalar is approximately equal to that of the streamwise velocity in terms of the growth rate of the half-widths. The scalar fluxes in the streamwise and wall-normal direction are found to be of comparable magnitude. The scalar mixing situation is further studied by evaluating the scalar dissipation rate and the mechanical to mixing time scale ratio.

  • 2516.
    Ahlman, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Brethouwer, Geert
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Johansson, Arne
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Direct numerical simulation of a reacting turbulent wall-jet2007Report (Other academic)
  • 2517.
    Ahlman, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Brethouwer, Geert
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Johansson, Arne
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Direct numerical simulation of non-isothermal turbulent wall-jets2009In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 21, no 3Article in journal (Refereed)
    Abstract [en]

    Direct numerical simulations of plane turbulent nonisothermal wall jets are performed and compared to the isothermal case. This study concerns a cold jet in a warm coflow with an ambient to jet density ratio of ρa/ρj = 0.4, and a warm jet in a cold coflow with a density ratio of ρa/ρj = 1.7. The coflow and wall temperature are equal and a temperature dependent viscosity according to Sutherland’s law is used. The inlet Reynolds and Mach numbers are equal in all these cases. The influence of the varying temperature on the development and jet growth is studied as well as turbulence and scalar statistics. The varying density affects the turbulence structures of the jets. Smaller turbulence scales are present in the warm jet than in the isothermal and cold jet and consequently the scale separation between the inner and outer shear layer is larger. In addition, a cold jet in a warm coflow at a higher inlet Reynolds number was also simulated. Although the domain length is somewhat limited, the growth rate and the turbulence statistics indicate approximate self-similarity in the fully turbulent region. The use of van Driest scaling leads to a collapse of all mean velocity profiles in the near-wall region. Taking into account the varying density by using semilocal scaling of turbulent stresses and fluctuations does not completely eliminate differences, indicating the influence of mean density variations on normalized turbulence statistics. Temperature and passive scalar dissipation rates and time scales have been computed since these are important for combustion models. Except for very near the wall, the dissipation time scales are rather similar in all cases and fairly constant in the outer region.

  • 2518.
    Ahlman, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Brethouwer, Gert
    KTH, School of Engineering Sciences (SCI), Mechanics, Turbulence.
    Johansson, Arne V.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Direct numerical simulation of mixing in a plane compressible and turbulent wall jet2005In: 4th International Symposium on Turbulence and Shear Flow Phenomena, 2005, p. 1131-1136Conference paper (Refereed)
    Abstract [en]

    Direct numerical simulation (DNS) is used to simulate the mixing of a passive scalar in a plane compressible and turbulent wall jet. The Mach number of the jet is M = 0.5 at the inlet. The downstream development of the jet is studied and compared to experimental data. Mixing in the inner and outer shear layers of the wall jet is investigated through scalar fluxes, the probability density function of the scalar concentration and the joint probability density function of the wall normal velocity fluctuation and the scalar concentration

  • 2519.
    Ahlmark, David
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Trajectory Optimization for Aircraft Evasive Maneuvering2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this work has been to identify hidden parameter value patterns during evasive maneuvering for a typical jet fighter. The work has created a performance model for a fighter aircraft and this model has then been combined with a missile model to simulate an enemy attack. By doing different kinds of simulations with a certain amount of predetermined scenarios, different outcomes could be evaluated when making small changes in the maneuvers during each specific scenario. The span of parameters that conducts a flying airplane’s trajectory is vast and the evaluation of different decisions that is up on the table for a pilot in a given situation might give new insights when optimizing tactical air fighting scenarios.After evaluating different scenarios with different input values in form of different turn and climb angles etc, it was clear that small changes resulted in vast differences regarding the outcome, when being chased by the missile. By analyzing the results, it can be concluded that there are underlying patterns regarding controllable parameter values when the airplane tries to get rid of the chasing missile. For example; one section in this work describes that by keeping a straight flight path for a certain amount of seconds after a specified value of turn angle - results in survival of the attack. Keeping level flight for too many seconds however has a lethal outcome. The results seem also to follow a continuous - non-randomized - pattern. This type of detailed analysis could be used to help a pilot to optimizise the performance of the maneuver.

  • 2520.
    Ahlmark, Jonatan
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Adding Layers: Adaptive Reuse in Tensta Centrum2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project examines how a new structure could be added on top a 60’s school building without interfering with its structurally order and aesthetical manifestation. A new space for the citizens of Tensta, a hovering glass box that puts Tensta Centrum on the map. Together with new office spaces for the City District Administration it would work as a catalytic effect for the area. New spatial qualities emerges and the composition, the old vs the new, together creates Tensta’s new Town Hall.

  • 2521.
    Ahlmer, Anna-Klara
    et al.
    KTH. Trivector Traff, Stockholm, Sweden.
    Cavalli, Marco
    CNR, Res Inst Geohydrol Protect, Padua, Italy..
    Hansson, Klas
    Swedish Transport Adm Trafikverket, S-17290 Stockholm, Sweden..
    Koutsouris, Alexander J.
    Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden..
    Crema, Stefano
    CNR, Res Inst Geohydrol Protect, Padua, Italy..
    Kalantari, Zahra
    Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden.;Stockholm Univ, Bolin Ctr Climate Res, S-10691 Stockholm, Sweden..
    Soil moisture remote-sensing applications for identification of flood-prone areas along transport infrastructure2018In: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 77, no 14, article id 533Article in journal (Refereed)
    Abstract [en]

    The expected increase in precipitation and temperature in Scandinavia, and especially short-time heavy precipitation, will increase the frequency of flooding. Urban areas are the most vulnerable, and specifically, the road infrastructure. The accumulation of large volumes of water and sediments on road-stream intersections gets severe consequences for the road drainage structures. This study integrates the spatial and temporal soil moisture properties into the research about flood prediction methods by a case study of two areas in Sweden, Vastra Gotaland and Varmland, which was affected by severe flooding in August 2014. Soil moisture data are derived from remote-sensing techniques, with a focus on the soil moisture-specific satellites ASCAT and SMOS. Furthermore, several physical catchments descriptors (PCDs) are analyzed and the result shows that larger slopes and drainage density, in general, mean a higher risk of flooding. The precipitation is the same; however, it can be concluded that more precipitation in most cases gives higher soil moisture values. The lack, or the dimensioning, of road drainage structures seems to have a large impact on the flood risk as more sediment and water can be accumulated at the road-stream intersection. The results show that the method implementing soil moisture satellite data is promising for improving the reliability of flooding.

  • 2522.
    Ahlquist, Mårten
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Fabrizi, G
    Cacchi, S
    Norrby, Per-Ola
    Technical University of Denmark.
    Palladium(0) alkyne complexes as active species: a DFT investigation2005In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 33, p. 4196-4198Article in journal (Refereed)
    Abstract [en]

    Alkynes have been found to be excellent ligands for Pd(0); the stability of a range of alkyne-Pd(0) complexes, and their reactivity in oxidative addition, have been investigated by DFT methods.

  • 2523.
    Ahlquist, Mårten
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Fabrizi, Giancarlo
    Cacchi, Sandro
    Norrby, Per-Ola
    Technical Univeristy of Denmark.
    The mechanism of the phosphine-free palladium-catalyzed hydroarylation of alkynes2006In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 39, p. 12785-12793Article in journal (Refereed)
    Abstract [en]

    The mechanism of the Pd-catalyzed hydroarylation and hydrovinylation reaction of alkynes has been studied by a combination of experimental and theoretical methods (B3LYP), with an emphasis on the phosphine-free version. The regioselectivity of the hydroarylation and hydrovinylation shows unexpected differences, which could be attributed mainly to the higher steric demand of the cyclohexenyl group as compared to the phenyl group. Hydroarylation of alpha,beta-acetylenic carbonyl substrates yields a very unusual anti-Michael selectivity, which is shown to result from reaction of the nonconjugated double bond, leaving the conjugation intact. In all cases were the regioselectivities reproduced by the calculations.

  • 2524.
    Ahlquist, Mårten
    et al.
    Scripps Research Insititute.
    Fokin, Valery V.
    Enhanced reactivity of dinuclear Copper(I) acetylides in dipolar cycloadditions2007In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 26, no 18, p. 4389-4391Article in journal (Refereed)
    Abstract [en]

    Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate itself. These findings support the experimentally determined rate law and shed light on the origin of high reactivity of the in situ generated copper acetylides.

  • 2525.
    Ahlquist, Mårten
    et al.
    Technical University of Denmark.
    Fristrup, P
    Tanner, David
    Technical University of Denmark.
    Norrby, Per-Ola
    Technical Univeristy of Denmark.
    Theoretical evidence for low-ligated palladium(0): [Pd-L] as the active species in oxidative addition reactions2006In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 25, no 8, p. 2066-2073Article in journal (Refereed)
    Abstract [en]

    The oxidative addition of PhI to Pd-O has been studied by DFT with a continuum representation of the solvent. It is shown that the preferred number of ligands on palladium is lower than would be expected from "conventional wisdom" and the 18-electron rule. The most favored oxidative addition is obtained when Pd is coordinated by only the aryl iodide and one additional ligand in a linear arrangement. The calculations indicate that p-orbitals on the central metal are not involved in bonding in any of the complexes described herein, in good agreement with classic ligand field theory and also with a recent bonding analysis by Weinhold and Landis, but in apparent violation of the 18-electron rule.

  • 2526.
    Ahlquist, Mårten
    et al.
    Lund University.
    Gustafsson, Mikaela
    Karlsson, Magnus
    Thaning, Mikkel
    Axelsson, Oskar
    Wendt, Ola F.
    Rhodium(I) hydrogenation in water: Kinetic studies and the detection of an intermediate using C-13{H-1} PHIPNMR spectroscopy2007In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 360, no 5, p. 1621-1627Article in journal (Refereed)
    Abstract [en]

    The mechanism for hydrogenation of dimethylmaleate in water using cationic rhodium complexes with water-soluble bi-dentate phosphines has been investigated using kinetics and a novel method for the indirect detection of intermediates in catalytic hydrogenation reactions, whereby a late intermediate was detected. A mechanism is proposed involving fast, irreversible substrate binding followed by a rate-determining reaction with dihydrogen.

  • 2527.
    Ahlquist, Mårten
    et al.
    Technical University of Denmark.
    Kozuch, S
    Shaik, S
    Tanner, David
    Technical University of Denmark.
    Norrby, Per-Ola
    Technical Univeristy of Denmark.
    On the performance of continuum solvation models for the solvation energy of small anions2006In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 25, no 1, p. 45-47Article in journal (Refereed)
    Abstract [en]

    The determination of continuum solvation models for the solvation energy of anions, was described. To investigate the reliability of the solvent model, a few explicit THF molecules were incorporated. A set of anions was chosen for which the experimental free energiesof solvation were available for both H 2O and DMSO solutions. A major difference between the water model and the DMSO model is that the latter systematically overestimates the free energy of solvation. The full water model in Jaguar v 4.2, including also nonelectrostatic terms, gives good correlation with experimental values for energy of solvation.

  • 2528.
    Ahlquist, Mårten
    et al.
    Technical University of Denmark.
    Nielsen, Robert J.
    Periana, Roy A.
    Goddard, William A., III
    Product Protection, the Key to Developing High Performance Methane Selective Oxidation Catalysts2009In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 47, p. 17110-17115Article in journal (Refereed)
    Abstract [en]

    Selective, direct conversion of methane to methanol might seem an impossible task since the C-H bond energy of methane is 105 kcal mol(-1) compared to the C-H bond energy for methanol of 94. We show here that the Catalytica catalyst is successful because the methanol is protected as methyl bisulfate, which is substantially less reactive than methanol toward the catalyst. This analysis suggests a limiting performance for systems that operate by this type of protection that is well above the Catalytica system.

  • 2529.
    Ahlquist, Mårten
    et al.
    Technical University of Denmark.
    Nielsen, T E
    Le Quement, S
    Tanner, David
    Technical University of Denmark.
    Norrby, Per-Ola
    Technical Univeristy of Denmark.
    An experimental and theoretical study of the mechanism of stannylcupration of alpha, beta-acetylenic ketones and esters2006In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 12, no 10, p. 2866-2873Article in journal (Refereed)
    Abstract [en]

    The title reaction has been investigated by experimental and computational (DFT) techniques, and subsequently compared to the corresponding carbocupration reaction, with particular emphasis oil the stereoselectivity. For stannylcupration of an ynone substrate, only the anti-addition product is observed, whereas for the corresponding ynoate substrate, the stereoselectivity can be affected by the reaction conditions: in the presence of methanol as proton donor, the initial syn-addition product can be trapped, whereas a syn/anti mixture is obtained in a non-protic solvent. This is in sharp contrast to the carbocupration of the same ynone substrate with a cyanocuprate (RCu(CN)Li), which is highly selective for syn-addition. The product selectivities can be understood from a detailed computational characterization of the reaction paths, and in particular from the relative stabilities of the vinyl cuprate and allenolate intermediates. It is suggested that the stereodetermining step is protonation of vinyl cuprate intermediates.

  • 2530.
    Ahlquist, Mårten
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Norrby, Per-Ola
    Department of Chemistry, University of Gothenburg, Sweden.
    Dispersion and Back-Donation Gives Tetracoordinate [Pd(PPh3)4]2011In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 50, no 49, p. 11794-11797Article in journal (Refereed)
    Abstract [en]

    18e R.I.P. The apparent compliance of [Pd(PPh3)4] ("tetrakis") with the 18-electron rule is not due to an electronic preference on the central metal. Pd is valence-saturated already by two ligands. Further ligand addition gives a minor energy gain, and is only possible due to strong back-bonding. Dispersion corrections are needed for properly describing the interactions between the ligands.

  • 2531.
    Ahlquist, Mårten
    et al.
    Technical University of Denmark.
    Norrby, Per-Ola
    Göteborg University.
    Oxidative addition of aryl chlorides to monoligated palladium(0): A DFT-SCRF study2007In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 26, no 3, p. 550-553Article in journal (Refereed)
    Abstract [en]

    Oxidative addition of aryl chlorides to palladium has been investigated by hybrid density functional theory methods (B3LYP), including a continuum model describing the solvent implicitly. A series of para-substituted aryl chlorides were studied to see the influence of electronic effects on the reaction. It was found that the experimentally observed higher reactivity of the more electron deficient aryl chlorides is due to their ability to accept back-donation from Pd-0 and form reasonably strong pre-reactive complexes. This effect is less pronounced in the transition state; when it is measured from the pre-reactive complex, the barrier to oxidative addition is actually higher for the electron-deficient aryl chlorides, but the overall reaction barrier is still lower than for the electron-rich aryl chlorides.

  • 2532.
    Ahlquist, Mårten
    et al.
    California Institute of Technology.
    Periana, Roy A.
    Goddard, William A., III
    C-H activation in strongly acidic media. The co-catalytic effect of the reaction medium2009In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 17, p. 2373-2375Article in journal (Refereed)
    Abstract [en]

    Quantum mechanical (QM) results are used to establish the role of sulfuric acid solvent in facilitating the reaction between Pt(II)(bpym)Cl(2) (bpym = 2,2'-bipyrimidinyl) and methane; coordination of methane to the platinum catalyst is found to be catalyzed by the acidic medium.

  • 2533.
    Ahlquist, Mårten S. G.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Iridium catalyzed hydrogenation of CO2 under basic conditions-Mechanistic insight from theory2010In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 324, no 1-2, p. 3-8Article in journal (Refereed)
    Abstract [en]

    The iridium(III) catalyzed hydrogenation of carbon dioxide under basic conditions was studied with density functional theory. It was found that the insertion of CO2 into an Ir-H bond proceeds via a two-step mechanism. The rate-limiting step was calculated to be the regeneration of the iridium(III) trihydride intermediate, and the overall barrier for the reaction was calculated to 26.1 kcal mol(-1). The formation of the iridium trihydride proceeds via formation of a cationic Ir(H)(2)(H-2) complex at which the base abstracts a proton from the dihydrogen ligand. (C) 2010 Elsevier B.V. All rights reserved.

  • 2534.
    Ahlquist, Mårten S. G.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Marcos-Escartin, Rocio
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Bicarbonate hydrogenation by iron: Effects of solvent and ligand on the mechanism2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
  • 2535.
    Ahlquist, Mårten S. G.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Norrby, Per-Ola
    Department of Chemistry, University of Gothenburg, Sweden.
    Dispersion and back-donation gives tetracoordinate Pd(PPh3)(4)2012In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 2536.
    Ahlquist, Mårten S. G.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Wang, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Xue, Liqin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Sanchez-de-Armas, Rocio
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Proton transfers in first row transition metal complexes2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 1381-INOR-Article in journal (Other academic)
  • 2537.
    Ahlquist, Mårten
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Zhan, Shaoqi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Modeling molecular water oxidation catalysts at interfaces2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
  • 2538.
    Ahlqvist, Eric
    KTH, School of Engineering Sciences (SCI).
    Fusion Systems On Finite Groups and Alperin's Theorem2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Let G be a group and P a Sylow p-subgroup of G. A fusion system of G on P, denoted by FP (G), is the category with objects; subgroups of P, and morphisms induced by conjugation in G. This thesis gives a brief introduction to the theory fusion systems.

    Two classical theorems of Burnside and Frobenius are stated and proved. These theorems may be seen as a starting point of the theory of fusion systems, even though the axiomatic foundation is due to Puig in the early 1990's.

    An abstract fusion system F on a p-group P is dened and the notion of a saturated fusion system is discussed. It turns out that the fusion system of any nite group is saturated, but the converse; that a saturated fusion system is realizable on a nite group, is not always true.

    Two versions of Alperin's fusion theorem are stated and proved. The first one is the classical formulation of Alperin and the second one, due to Puig, a version stated in the language of fusion systems. The differences between these two are investigated.

    The fusion system F of GL2 (3) on the Sylow 2-subgroup isomorphicto SD16 is determined and the subgroups generating F are found.

  • 2539.
    Ahlqvist, Eric
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Operations on Étale Sheaves of Sets2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rydh showed in 2011 that any unramified morphism ƒof algebraic spaces (algebraic stacks) has a canonical and universal factorization through an algebraic space (algebraic stack) called the étale envelope of ƒ, where the first morphism is a closed immersion and the second is étale. We show that when ƒ is étale then the étale envelope can be described by applying the left adjoint of the pullback of ƒ to the constant sheaf defined by a pointed set with two elements. When ƒ is a monomorphism locally of finite type we have a similar construction using the direct image with proper support.

  • 2540. Ahlqvist, J.
    et al.
    Kumar, A.
    Sundstrom, H.
    Ledung, E.
    Hornsten, E. G.
    Enfors, Sven-Olof
    KTH, School of Biotechnology (BIO), Bioprocess Technology.
    Mattiasson, B.
    Affinity binding of inclusion bodies on supermacroporous monolithic cryogels using labeling with specific antibodies2006In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 122, no 2, p. 216-225Article in journal (Refereed)
    Abstract [en]

    A new chromatographic method based on affinity supermacroporous monolithic cryogels is developed for binding and analyzing inclusion bodies during fermentation. The work demonstrated that it is possible to bind specific IgG and IgY antibodies to the 15 and 17 amino acids at the terminus ends of a 33 kDa target protein aggregated as inclusion bodies. The antibody treated inclusion bodies from lysed fermentation broth can be specifically retained in protein A and pseudo-biospecific ligand sulfamethazine modified supermacroporous cryogels. The degree of binding of IgG and IgY treated inclusion bodies to the Protein A and sulfamethazine gels are investigated, as well as the influence of pH on the sulfamethazine ligand. Optimum binding of 78 and 72% was observed on both protein A and sulfamethazine modified cryogel columns, respectively, using IgG labeling of the inclusion bodies. The antibody treated inclusion bodies pass through unretained in the sulfamethazine supermacroporous gel at pH that does not favour the binding between the ligand on the gel and the antibodies on the surface of inclusion bodies. Also the unlabeled inclusion bodies went through the gel unretained, showing no non-specific binding or trapping within the gel. These findings may very well be the foundation for the building of a powerful analytical tool during fermentation of inclusion bodies as well as a convenient way to purify them from fermentation broth. These results also support our earlier findings [Kumar, A., Plieva, F.M., Galaev, I.Yu., Mattiasson, B.. 2003. Affinity fractionation of lymphocytes using a monolithic cyogel. J. Immunol. Methods 283, 185-194] with mammalian cells that were surface labeled with specific antibodies and recognized on protein A supermacroporous gels. A general binding and separation system can be established on antibody binding cryogel affinity matrices.

  • 2541.
    Ahlqvist, Oscar
    et al.
    KTH, School of Computer Science and Communication (CSC).
    Åkermark, Wilhelm
    KTH, School of Computer Science and Communication (CSC).
    Examining the Implications of Adding Sentiment Analysis when Clustering based on Party Affiliation through Twitter2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Political discussion is very common and a popular statistic for the politically interested are the surveys determining people’s party affiliation. Today they are done manually but it would be beneficial if there was an automated method which could produce the same or similar results. On the social network Twitter there are a lot of users discussing politics, all from political leaders and representatives to just regular people with an interest for the subject. Because of that and also for its convenience when it comes to collecting data, Twitter has been used before in previous work to cluster political users based on what they are discussing. What has not been done before which this thesis contributes is clustering with sentiment analysis. In other terms, trying to cluster people based on what they are discussing but also if their opinion is positive or negative. What was noted in this work was that the part of clustering without sentiment analysis, that had been done in previous studies, was successfully replicated. However adding the sentiment analysis did not give the desired effect and only worsened the results.

  • 2542.
    Ahlqvist, Sigge
    KTH, School of Engineering Sciences (SCI).
    Analyzing a collateral backed pricestability implementation in a pricestable cryptocurrency2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A price stability implementation in a proposed collateral backed cryptocurrency was assessed in order to identify which factors increased its robustness and improve on the design. The dynamics of the cryptocurrency were modelled as a stochastic dynamical system and put to the test under different scenarios. The results emphasized the importance of using low volatility currencies to create a basket of collateral assets. Cryptocurrencies was regarded as inappropriate due to their generally high price volatility. A large degree of collateralization was also deemed important for system stability. In order to avoid a permanent failure of the system, the results found that the most beneficial design would be to allow the price to collapse under controlled circumstances in the event of critical undercollateralization. This allowed the system to recover to a collateralized state over time. Evidence was also found of the possibility to influence the risk of undercollateralization by optimizing the allowed deviations from the target price depending on the the cryptocurrency’s own price volatility.

  • 2543.
    Ahlroth, Mikael
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Analysis of closed cycle gas turbines for biomass fuel2000Licentiate thesis, comprehensive summary (Other scientific)
  • 2544.
    Ahlroth, Sofia
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Convergent validity test of structural benefit transfer: the case of water qualityManuscript (preprint) (Other academic)
  • 2545.
    Ahlroth, Sofia
    KTH, Superseded Departments, Civil and Environmental Engineering.
    Correcting NDP for SO2 and NOx emissions: Implementation of a theoretical model in practice2003In: The Review of Income and Wealth, ISSN 0034-6586, E-ISSN 1475-4991, no 3, p. 425-440Article in journal (Refereed)
    Abstract [en]

    The theoretical and the practical studies in the field of environmental accounting are often two separate lines of work. In this study, we develop an optimal control theory model for adjusting NDP for the effects of SO2 and NOx emissions, and subsequently insert empirically estimated values. The model includes correction entries for the effects on welfare, real capital, health and the quality and quantity of renewable natural resources. In the empirical valuation study, production losses were estimated with dose-response functions. Recreational and other welfare values were estimated by the contingent valuation (CV) method. Effects on capital depreciation are also included. For comparison, abatement costs and environmental protection expenditures for reducing sulfur and nitrogen emissions were estimated. The theoretical model was then utilized to calculate the adjustment to NDP in a consistent manner. The estimated damage value of sulfur is close to the Swedish sulfur tax.

  • 2546.
    Ahlroth, Sofia
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategic Analysis.
    Costs and benefits of climate change : a bottom-up analysisManuscript (preprint) (Other academic)
  • 2547.
    Ahlroth, Sofia
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies (moved 20130630).
    Developing a weighting set based on monetary damage estimates: Method and case studies2009Report (Other academic)
    Abstract [en]

    In environmental systems analysis tools such as cost-benefit analysis (CBA) and life-cycle assessments (LCA), generic values for impacts on the environment and human health are frequently used. There are several sets of generic values, which are based on different valuation methods, e.g. willingness-to-pay, abatement costs, taxes or non-monetary assessments. This study attempts to derive a consistent set of damage-based values based on estimation of willingness to pay (WTP) to avoid damages. Where possible we compile existing damage cost estimates from different sources. Currently, there are no generic damage costs available for eutrophication and acidification. We derive damage values for eutrophying and acidifying substances using WTP estimates from available valuation studies. For eutrophication, we derive benefit transfer functions for eutrophication that allows calculation of site-specific values. We compare the derived ecosystem damage values to existing estimates of the cost for reducing nitrogen and phosphorus emissions to water. The analysis indicates that many abatement measures for nitrogen have a positive net benefit while most measures to reduce phosphorus cost more than the benefit achieved when estimated on a general level and should, instead, be assessed on a case-specific level. Moreover, a comparison of the existing environmental taxes on nitrogen, nitrogen oxides and phosphorus in Sweden show that the current tax rates do not reflect the externalities from these pollutants. Subsequently, we construct a weighting set by combining the derived values with existing generic damage values for human toxicity, photochemical oxidants and global warming. The weighting set - labelled Ecovalue09 - is applied to three case studies and the outcome is compared to the results using other weighting sets.

  • 2548.
    Ahlroth, Sofia
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies.
    Valuation of environmental impacts and its use in environmental systems analysis tools2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Valuation of environmental impacts in monetary terms is a both difficult and controversial undertaking. However, the need to highlight the value of ecosystem services in policy decisions has become more and more evident in the face of climate change and diminishing biodiversity in the sea and other ecosystems. Valuing non-market goods and services, like ecosystem services, is a lively research field within environmental economics, and valuation methods have been considerably elaborated in the last ten years. In practical policy analyses, there is often a need for readily available valuations of different impacts. This thesis explores and develops several ways to include valuation of environmental impacts in different policy tools, such as cost-benefit analysis, environmental accounting and life-cycle analysis.

    The first paper in this thesis is a part of the Swedish attempts to construct and calculate an environmentally adjusted NDP (net national product). This work involved putting a price on non-marketed environmental goods and assets. The valuation methods used in paper I include many of the available methods to value non-marketed goods and services.

    Valuation of environmental impacts and/or environmental pressures is used in a number of environmental systems analysis tools besides environmental accounting. Examples are Cost-Benefit Analysis, Life Cycle Assessment, Life Cycle Cost analysis, Strategic Environmental Assessment and Environmental Management Systems. These tools have been developed in different contexts and for different purposes; the way valuation is used also differs. In paper II, the current use of values/weights in the tools is explored, as well as the usefulness of a common valuation/weighting scheme and necessary qualities of such a scheme. In the third paper, a set of generic weights meeting these criteria is developed.

    Some of the generic values in the weighting set are taken from directly from other studies, while some are calculated by applying a benefit transfer method called structural benefit transfer on results from selected valuation studies. The method is tested on a number of valuation studies in the fourth paper.

    Climate change will have a significant impact on Sweden during this century, both positive and negative. In the fifth paper, a rough estimate of the impacts on man-made capital and human health is presented. The study is an example of an impact assessment including only marketed assets valued with market prices. In the last paper, the economics of sustainable energy use is discussed; what is a sustainable energy price, and how might growth be affected if energy use is limited to a sustainable level? The discussion is based on two different models of thought: a back-casting study, describing how a sustainable future society might look like, and economic scenarios projected with general equilibrium models.

  • 2549.
    Ahlroth, Sofia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategic Analysis.
    Finnveden, Göran
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategic Analysis.
    Ecovalue08-a new valuation method for environmental systems analysis toolsManuscript (preprint) (Other academic)
  • 2550.
    Ahlroth, Sofia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies.
    Finnveden, Göran
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies. School of Computer Science and Communication (CSC), Centres, KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Sustainable Communications, CESC.
    Ecovalue08-A new valuation set for environmental systems analysis tools2011In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 19, no 17-18, p. 1994-2003Article in journal (Refereed)
    Abstract [en]

    In environmental systems analysis tools such as cost-benefit analysis (CBA), life-cycle assessment (LCA) and Environmental Management Systems (EMS), weighting is often used to aggregate results and compare different alternatives. There are several weighting sets available, but so far there is no set that consistently use monetary values based on actual or hypothetical market valuation of environmental degradation and depletion. In this paper, we develop a weighting set where the values are based on willingness-to-pay estimates for environmental quality, and market values for resource depletion. The weighting set is applied to three case studies and the outcome is compared with the outcomes from three other weighting sets. Ecotax02, Ecoindicator99 and EPS2000. We find that the different sets give different results in many cases. The reason for this is partly that they are based on different values and thus should give different results. However, the differences can also be explained by data gaps and different methodological choices. If weighting sets are used, it is also important to use several to reduce the risk of overlooking important impacts due to data gaps. It is also interesting to note that though Ecovalue08 and Ecotax02 give different absolute values, the results are very similar in relative terms. Thus the political and the individual willingness-to-pay estimates yield a similar ranking of the impacts.

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