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  • 51.
    Sörlin, Sverker
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science and Technology (name changed 20120201).
    När naturen blev en del av framtiden2009In: Sveriges Natur, ISSN 0039-6974, no 2, p. 42-47Article in journal (Other (popular science, discussion, etc.))
  • 52.
    von Holst, Hans
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Sveinsveink
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Ho, Johnson
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Non-invasive brain injury evaluation2009Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A non-invasive method for measuring intracranial pressure (ICP) is provided. A numerical model such as finite element model is developed in order to calculate the ICP, strain or stress for patients who suffers from hematoma, edema or tumor. The method can further provide local maximum principle strain that can provide information about possible subsequent brain injury, such as diffuse axonal injury, in sensitive region of the brain. Based on computer tomography or magnetic resonance images an individual diagnosis and treatment plan can be formed for each patient.

    (FR)L'invention concerne un procédé non invasif visant à mesurer la pression intracrânienne (ICP). Un modèle numérique tel qu’un modèle par éléments finis est développé afin de calculer l’ICP, la déformation ou la contrainte pour des patients souffrant d’un hématome, d’un œdème ou d’une tumeur. Le procédé peut en outre fournir le maximum local de déformation principale qui peut donner des informations concernant d’éventuelles lésions cérébrales subséquentes, comme des lésions axonales diffuses, dans une région sensible du cerveau. Sur la base d’une tomographie informatisée ou d’images par résonance magnétique, un diagnostic et un plan de traitement individualisés peuvent être formulés pour chaque patient.

  • 53.
    Vu, Tuong Thuy
    Grid Technology Research Center, National Institute of Advanced Industrial Science and Technology.
    Monitoring the Recovery Process of the Disaster-Affected Areas -Scaling Context Image Analysis in GEO Grid-Based Solution2008In: INTERNATIONAL ARCHIVES OF PHOTOGRAMMETRY REMOTE SENSING AND SPATIAL INFORMATION SCIENCES, Elsevier, 2008, Vol. 11, no 4, p. 1625-1630Conference paper (Refereed)
    Abstract [en]

    This paper presents a new remotely sensed solution for monitoring the recovery of a large disaster-affected area. It exploits thepowerful data grid and computing grid technologies developed on GEO (Global Earth Observation) Grid system. Accessing theASTER portal site of GEO Grid, all the necessary ASTER multi-spectral images and on-demand ASTER digital elevation model(DEM) are easily and quickly collected. Subsequently, satellite images are automatically analyzed on a grid-based computingmechanism. The core processing is a newly developed context-based mapping approach named scaling context image analysis.Phanga province of Thailand, which was strongly attacked by the 2004 Indian Ocean tsunami, is selected as the demonstration site.Four ASTER data sets acquired on November 15, 2002 (pre-event); December 31, 2004 (just after-event); February 8, 2005 andJanuary 26, 2006 (post-event) are used. The efficiency in data collection and data computation is the merit of the proposed solution.

  • 54.
    Wettlaufer, John
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Surface phase transitions in ice: From fundamental interactions to applications2019In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 377, no 2146, article id 20180261Article in journal (Refereed)
    Abstract [en]

    Interfaces divide all phases of matter and yet in most practical settings it is tempting to ignore their energies and the associated implications. There are many reasons for this, not the least of which is the introduction of a new pair of canonically conjugate variables-interfacial energy and its counterpart the surface area. A key set of questions surrounding the treatment of multiphase flows concerns how and when we must account for such effects. I begin this discussion with an abbreviated review of the basic theory of lower-dimensional phase transitions and describe a range of situations in which the bulk behaviour of a two-phase (and in some cases twocomponent) system is dominated by surface effects. Then I discuss a number of settings in which the bulk and surface behaviour can interact on equal footing. These can include the dynamic and thermodynamic behaviour of floating sea ice, the freezing and drying of colloidal suspensions (such as soil) and the mechanisms of protoplanetesimal formation by inter-particle collisions in accretion discs. This article is part of the theme issue 'The physics and chemistry of ice: Scaffolding across scales, from the viability of life to the formation of planets'. © 2019 Royal Society Publishing. All rights reserved.

  • 55.
    Wu, Sihong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Physics.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Physics.
    Kolari, Pasi
    Department of Forest Ecology, University of Helsinki, Finland.
    Modeling seasonal courses of carbon fluxes and evaportranspiration in response to low temperature and moisture in a boreal scots pine ecosystem2011In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 222, p. 3103-3119Article in journal (Refereed)
    Abstract [en]

    Environmental conditions act above and below ground, and regulate carbon fluxes and evapotranspiration. The productivity of boreal forest ecosystems is strongly governed by low temperature and moisture conditions, but the understanding of various feedbacks between vegetation and environmental conditions is still unclear. In order to quantify the seasonal responses of vegetation to environmental factors, the seasonality of carbon and heat fluxes and the corresponding responses for temperature and moisture in air and soil were simulated by merging a process-based model (CoupModel) with detailed measurements representing various components of a forest ecosystem in Hyytiälä, southern Finland. The uncertainties in parameters, model assumptions, and measurements were identified by generalized likelihood uncertainty estimation (GLUE). Seasonal and diurnal courses of sensible and latent heat fluxes and net ecosystem exchange (NEE) of CO2 were successfully simulated for two contrasting years. Moreover, systematic increases in efficiency of photosynthesis, water uptake, and decomposition occurred from spring to summer, demonstrating the strong coupling between processes. Evapotranspiration and NEE flux both showed a strong response to soil temperature conditions via different direct and indirect ecosystem mechanisms. The rate of photosynthesis was strongly correlated with the corresponding water uptake response and the light use efficiency. With the present data and model assumptions, it was not possible to precisely distinguish the various regulating ecosystem mechanisms. Our approach proved robust for modeling the seasonal course of carbon fluxes and evapotranspiration by combining different independent measurements. It will be highly interesting to continue using long-term series data and to make additional tests of optional stomatal conductance models in order to improve our understanding of the boreal forest ecosystem in response to climate variability and environmental conditions.

  • 56.
    Zaheer, Muhammad
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Kinematic orbit determination of low Earth orbiting satellites, using satellite-to-satellite tracking data and comparison of results with different propagators2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The GPS data from Challenging Mini-satellite Payload (CHAMP) is used for its orbit determination for the epoch day of January 1st 2002.  The orbit of CHAMP is computed from the GPS data and ionospheric effects are removed by frequency combination.

    Further, the orbits of CHAMP for the same epoch day are computed using the satellite tool kit (STK) employing simplified general perturbations (SGP4) and a high precision orbit propagator (HPOP). Results from both techniques (GPS computed orbit and STK computed orbit) are compared.

    Furthermore, orbits computed using GPS data are also compared with jet propulsion laboratory’s published CHAMP spacecraft orbit and we have found that root mean square difference in ECEF position X component is below 0.01km other than some spikes at poles. The standard deviation of the difference in ECEF position X coordinate is 11.7m.

    The accuracy of our computed satellite positions (using GPS data) is about 12 metres for other than polar areas. However there are some occasional spikes, especially at poles, having maximum errors (about 0.055 km).

  • 57.
    Zaheer, Muhammad
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Kinematic orbit determination of low Earth orbiting satellites, using satellite-to-satellite tracking data and comparison of results with different propagators2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    GPS data from Challenging Mini-satellite Payload (CHAMP) is used for its orbit determination for the epoch day of January 1st 2002.  The orbit of CHAMP is computed from the GPS data and ionospheric effects are removed by frequency combination.

    Further, the orbits of CHAMP for the same epoch day are computed using the satellite tool kit (STK) employing simplified general perturbations (SGP4) and a high precision orbit propagator (HPOP).

    Furthermore, orbits computed using GPS data are also compared with jet propulsion laboratory’s published CHAMP spacecraft orbit and we have found that root mean square difference in ECEF position X component is below 0.01km other than some spikes at poles. The standard deviation of the difference in ECEF position X coordinate (JPL results – GPS computed results) is 11.7m. Since JPL computed orbits are considered as true orbits of CHAMP with accuracy of centimeter level (https://gipsy-oasis.jpl.nasa.gov/). Therefore this difference can also be referred as observed error in GPS computed orbits. Considering above discussion, we can expect that accuracy of our computed satellite positions (using GPS data) is about 12 metres for other than poles area. However there are some occasional spikes, especially at poles, having maximum errors (about 0.055 km).

  • 58.
    Österlöf, Rickard
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
    Modelling of the Fletcher-Gent effect and obtaining hyperelastic parameters for filled elastomers2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The strain amplitude dependency , i.e. the Fletcher-Gent effect and Payne effect, and the strain rate dependency of rubber with reinforcing fillers is modelled using a modified boundary surface model and implemented uniaxially. In this thesis, a split of strain instead of stress is utilized, and the storage and loss modulus are captured over two decades of both strain amplitudes and frequencies. In addition, experimental results from bimodal excitation are replicated well, even though material parameters were obtained solely from harmonic excitation. These results are encouraging since the superposition principle is not valid for filled rubber, and real-life operational conditions in general contain several harmonics. This means that formulating constitutive equations in the frequency domain is a cumbersome task, and therefore the derived model is implemented in the time domain. Filled rubber is used irreplaceable in several engineering solutions, such as tires, bushings, vibrations isolators, seals and tread belts, to name just a few. In certain applications, it is sufficient to model the elastic properties of a component during finite strains. However, Hooke’s law is inadequate for this task. Instead, hyperelastic material models are used. Finally, the thesis presents a methodology for obtaining the required material parameters utilizing experiments in pure shear, uniaxial tension and the inflation of a rubber membrane. It is argued that the unloading curve rather than the loading curve is more suitable for obtaining these parameters, even at very low strain rates.

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