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  • 124151.
    Ågerstrand, Marlene
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    Rudén, Christina
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    The Swedish environmental and classification system for pharmaceuticals: An evaluation of the system’s achievements so far2010In: Towards Sustainable Pharmaceuticals in a Healthy Society / [ed] C Rudén, K Liljelund, H Hagerman, Elanders Sverige AB , 2010Chapter in book (Other academic)
  • 124152.
    Ågerstrand, Marlene
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    Rudén, Christina
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    Wester, Misse
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    The Swedish environmental information and classification scheme for pharmaceuticals - An empirical investigation of the motivations, intentions and expectations underlying its development and implementation2008In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 180, p. S177-S178Article in journal (Refereed)
  • 124153.
    Ågerstrand, Marlene
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy.
    Wester, Misse
    KTH, School of Architecture and the Built Environment (ABE), Philosophy.
    Rudén, Christina
    KTH, School of Architecture and the Built Environment (ABE), Philosophy.
    The Swedish Environmental Classification and Information System for Pharmaceuticals: An empirical investigation of the motivations, intentions and expectations underlying its development and implementation2009In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 35, no 5, p. 778-786Article in journal (Refereed)
    Abstract [en]

    In 2005 the Swedish Association of the Pharmaceutical Industry (LIF) initiated a national environmental classification and information system for pharmaceuticals. This investigation reports the results from a survey, conducted among the persons involved in the start-up process. The aim of this study is to generate knowledge contributing to the clarification of the motivations, expectations, and intentions underlying the development and implementation of the system. The decision to implement a classification and information system for pharmaceuticals was the result of a combination of several driving forces, mainly political pressure and a possibility to increase the industries' goodwill, while at the same time keeping the process under the industries' control. The expected possible effects of the system, other than increased goodwill, are according to this survey assumed to be low. The system offers little guidance for end-users in the substitution of one pharmaceutical for another. One possible reason for this could be that LIF needs to observe the interests of all its members' and should not affect competition. The affiliation of the involved actors correlates to how these actors view and value the system, but this has not hampered the collaborative process to develop and implement it.

  • 124154. Ågren, H.
    et al.
    Norman, P.
    Jonsson, D.
    Liegener, C.
    On the vibrational and orientational probing of surface-adsorbates by direct and resonance photoemission1994In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 311, no 3, p. 375-384Article in journal (Refereed)
    Abstract [en]

    Vibrationally resolved direct photoemission spectra of physisorbed molecules separated from the substrate by spacer layers, show remarkable splittings of vibronic progressions. The corresponding resonant photoemission spectra have recently confirmed these splittings and also revealed their strong dependence on the polarization of the exciting radiation. We apply a self-consistent mirror image model on the physisorbed nitrogen and oxygen molecules to explore the origin of these shifts and their dependence on the orientation of the adsorbate molecule with respect to the surface. The symmetry character and orientational probing of autoionization is analyzed for the resonant cases by a decomposition of the interacting matrix elements.

  • 124155.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Modeling of multi-photon-induced photoluminescence from organic fluorophores and metal-coated semiconductor nanoparticles2006In: Proceedings of International Symposium on Biophotonics, Nanophotonics and Metamaterials, 2006, p. 26-26Conference paper (Refereed)
    Abstract [en]

    In this talk I will describe some applications of multiphysics modeling of molecular and nano-particle materials that have been carried out at our department. Among the various multiphysics approaches, those that combine quantum mechanics with wave mechanics and quantum mechanics with statistical mechanics have turned out to be particularly powerful for predicting optical properties of organic fluorophores, respectively, nanoparticles. The first type of combined approach allows to estimate the optical transmission from cross sections of multi-photon absorption processes and from considerations of propagation and saturation effects. The other type of combined approach, quantum mechanics with statistical mechanics, allows to account for the spontaneous photon emission of two-photon excited quantum dots including the nonradiative energy dissipation process of phonon scattering. Multi-photon quantum dots offer the combined advantage of brilliance and photo-resistance of normal quantum dots with the 3-dimensional confocality and penetration of multi-photon excitation, something that can have a broad ramification on fluorescence based experiments in biology. We have in particular investigated multiphoton-induced photoluminescence from metal-coated coated quantum dots under the influence of electromagnetic field enhancement associated with surface plasmon resonances. It is argued that up-conversion luminescence of coated quantum dots is a promising approach for bio-imaging as it can generate the multiphoton excitation at reduced laser intensities.

  • 124156.
    Ågren, Hans
    et al.
    KTH, Superseded Departments, Biotechnology.
    Gel'mukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Kramers-Heisenberg and Weisskopf-Wigner descriptions of resonant X-ray Raman scattering2000In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 110, no 03-jan, p. 153-178Article in journal (Refereed)
    Abstract [en]

    An overview is presented of the theory of X-ray Raman scattering as originally formulated by Kramers and Heisenberg and by Weisskopf and Wigner. Two particular aspects of the theory are described in some detail; the formation of band profiles and the role of symmetry, These aspects are discussed in connection with recent results for atomic and molecular scatterers obtained in radiative and nonradiative scattering experiments conducted with 2nd and 3rd generation synchrotron radiation sources.

  • 124157.
    Ågren, Hans
    et al.
    KTH, Superseded Departments, Biotechnology.
    Gel'mukhanov, Faris
    KTH, Superseded Departments, Biotechnology.
    Salek, Pawel
    KTH, Superseded Departments, Biotechnology.
    Dynamics of Inner Shell Resonant Raman Scattering.1999In: Journal of the Japanese Society for Synchrotron Radiation Research, ISSN 0914-9287, Vol. 12, no 4, p. 257-267Article in journal (Refereed)
    Abstract [en]

    Some recent advances in the theory of the resonant Raman process for atoms, molecules and solids involving inner shell electrons are reviewed. Special emphasis is put on the dynamical aspects and on the notion of a duration time for the x-ray Raman process (RXS), which brings about a distinetion of processes with different time scales responsible for the formation of the spectral profile. This notion has been useful for actual predietions of various phenomena associated with RXS such as "symmetry restoration" "vibrational collapse", and "control of dissociation". The temporal theory of RXS is based on the wave packet formalism. The increase of the broad "molecular" parts relative to the atomic, or fragment, decay upon frequency detuning is demonstrated. The atomic-like resonance and molecular parts are proved to show different dispersion relations. Under certain conditions the interference between the molecular and atomic parts produces conspicuous "spectral holes". These conceptual tools are applicable also in the case of solids; there is an analogous restoration of momentum selection rules and a collapse effect upon detuning the frequency. Thus when the duration of the scattering is shortened by a large detuning, the role of electron-phonon coupling of the core excited states is suppresssed. The shortening of the RXS duration in a certain sense leads to a deloealization of the core hole in a solid. We describe also some new features that derive from the Doppler effect on ejected Auger electrons.

  • 124158.
    Ågren, Hans
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Harczuk, Ignat
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Vahtras, Olav
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Decomposition of molecular properties2019In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, no 5, p. 2251-2270Article in journal (Refereed)
    Abstract [en]

    We review recent work on property decomposition techniques using quantum emical methods and discuss some topical applications in terms of antum mechanics-molecular mechanics calculations and the constructing properties of large molecules and clusters. Starting out from the -called LoProp decomposition scheme [Gagliardi et al., J. Chem. Phys., 04, 121, 4994] for extracting atomic and inter-atomic contributions to lecular properties we show how this method can be generalized to calized frequency-dependent polarizabilities, to localized perpolarizabilities and to localized dispersion coefficients. Some plications of the generalized decomposition technique are reviewed - lculations of frequency-dependent polarizabilities, Rayleigh attering of large clusters, and calculations of hyperpolarizabilities proteins.

  • 124159.
    Ågren, Hans
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Mikkelsen, Kurt
    Homogeneous and heterogeneous solvent models for nonlinear optical properties2008In: Continuum Solvation Models in Chemical Physics: from theory to applications / [ed] Benedetta Mennucci; Roberto Cammi, John Wiley & Sons, 2008Chapter in book (Refereed)
  • 124160.
    Ågren, Hans
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Norman, Patrick
    Baev, Alexander
    Multiphysics modelling of optical materials2006In: Optical Materials in Defence Systems Technology III / [ed] Grote, JG; Kajzar, F; Lindgren, M, BELLINGHAM, WA: SPIE-INT SOC OPTICAL ENGINEERING , 2006, Vol. 6401, p. U8-U24Conference paper (Refereed)
    Abstract [en]

    We review multiphysics modeling of pulse propagation in non-linear media and highlight some recent applications on optical materials containing organic or organometallic chromophores.

  • 124161.
    Ågren, Hans
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Modeling of Non-linear Optic Properties of Guest-Host Systems2006In: Nonlinear Optics, Quantum Optics: concepts in modern optics, ISSN 1543-0537, Vol. 35, no 1-3, p. 39-55Article in journal (Refereed)
    Abstract [en]

    In this paper we summarize our recent work in computer modeling of nonlinear optical (NLO) properties of guest-host systems. The modeling involves quantum chemistry calculations to predict the NLO properties of a single chromophore molecule and molecular dynamics simulations to estimate the macroscopic NLO properties of the corresponding guest-host systems and to find the microscopic origin behind the macroscopic properties. The systems studied cover solutions solvated with NLO chromophores and amorphous polymers doped with dipolar chromophore molecules. Some gained insight and conclusions obtained from the combined modeling approaches are presented.

  • 124162.
    Ågren, Hans
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Modelling nonlinear optical effects in guest-host systems2005In: Chinese Optics Letters (COL), ISSN 1671-7694, Vol. 3, no Suppl., p. S17-S22Article in journal (Refereed)
    Abstract [en]

    We briefly outline a modelling strategy, combining quantum chemistry and molecular dynamics simulations, for obtaining macroscopic nonlinear optical coefficients in guest-host systems like chromophores in solutions or in polymer matrices. The parameters required for the calculation of the macroscopic nonlinear optical property, like the chromophore number density, local field factors, and the order parameter of the chromophore molecules, are derived. These parameters, together with the molecular first hyperpolarizabilities, obtained from quantum chemistry calculations, are used to estimate the macroscopic electro-optic coefficients. The combined approach leads to some new conclusions about the relation of the chromophore property and its solvent interactions in order to optimize the nonlinear optical coefficient. For instance, from the simulation results a totally different notion is derived about the collective properties of octupolar molecules. We find that such molecules receive a solvent induced dipole moment that makes it possible to pole them by an external electric field, but also that they can aggregate as an effect of this solvent interaction.

  • 124163. Ågren, J.
    et al.
    Kiamehr, Ramin
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Sjöberg, Lars
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Computation of a New Gravimetric Geoid Model over Sweden using the KTH Method: Paper presented at FIG working week, 14-18 June 2008, Stockholm, Sweden2008In: FIG working week, 2008Conference paper (Refereed)
  • 124164. Ågren, Jan
    et al.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Railway Technology.
    Flash Temperature in Wheel/Rail contact and Martensite Formation: A Review2006In: Proc. of the 7th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2006), 2006Conference paper (Refereed)
  • 124165.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Diffusion in multicomponent phases2008In: The SGTE Casebook: Thermodynamics At Work, Elsevier, 2008, 2, p. 347-350Chapter in book (Refereed)
  • 124166.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Multicomponent diffusion in compound steel2008In: The SGTE Casebook: Thermodynamics At Work, Elsevier Ltd , 2008, 2, p. 386-391Chapter in book (Other academic)
  • 124167.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Nucleation - A challenge in the modelling of phase transformations2015In: PTM 2015 - Proceedings of the International Conference on Solid-Solid Phase Transformations in Inorganic Materials, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015 , 2015, p. 9-14Conference paper (Refereed)
    Abstract [en]

    The modelling of phase transformations, once the nucleation event has occurred, may involve tedious computations but nevertheless methods based on sharp and diffuse interfaces have been quite successful and led to a deeper insight even in complex multicomponent materials. On the other hand nucleation is much more difficult to model. The difficulties stem from deficiencies in our fundamental understanding of nature, from lack of physical knowledge as well as problems involving computational efficiency. In the talk the classical theory of nucleation as well as various modifications over the years will be reviewed. Special emphasis will be given to the thermodynamics of small clusters, kinetics of fluctuations, multicomponent effects, and the rate of nucleation.

  • 124168.
    Ågren, John
    KTH, Superseded Departments, Metallurgy.
    On the classification of phase transformations2002In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 46, no 12, p. 893-898Article in journal (Refereed)
    Abstract [en]

    The various classification schemes, based on thermodynamics, microstructure or mechanism, are discussed and criticized from a practical as well as a more fundamental point of view. For example, it is generally not meaningful to consider first and second-order transformations as equivalent with heterogeneous and homogeneous transformations, respectively.

  • 124169.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    The materials genome and CALPHAD2014In: Chinese Science Bulletin, ISSN 1001-6538, E-ISSN 1861-9541, Vol. 59, no 15, p. 1635-1640Article in journal (Refereed)
    Abstract [en]

    The mapping of the human genome is an important basis for the development of new medicals and medical treatments. Consequently, it has attracted tremendous research funding over the last decade. On June 2011, the Materials Genome Initiative was announced by the US President Obama as collaboration on modeling and advanced materials databases. Unfortunately, the materials genome was given a rather vague definition in the announcement. However, the materials genome should be defined in analogy with biological genomes and one may then conclude that: at any moment, the performance of a specific material depends on its chemical composition ( inherent property stored in its genome) and its environment ( external interactions-processing-conditions during usage). The materials genome should thus be defined as a set of information encoded in the language of thermodynamics obtained by careful assessment of experimental data and quantum mechanical calculations from which certain conclusions about the material can be drawn. The CALPHAD databases contain the thermodynamic and kinetic properties of a materials system. Such databases allow the prediction of materials structure as well as its response to processing and usage conditions, and are major parts of integrated computational materials engineering.

  • 124170.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Thermodynamics and Diffusion Coupling in Alloys-Application-Driven Science2012In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 43A, no 10, p. 3453-3461Article in journal (Refereed)
    Abstract [en]

    As emphasized by Stokes (1997), the common assumption of a linear progression from basic research (science), via applied research, to technological innovations (engineering) should be questioned. In fact, society would gain much by supporting long-term research that stems from practical problems and has usefulness as a key word. Such research may be fundamental, and often, it cannot be distinguished from "basic" research if it were not for its different motivation. The development of the Calphad method and the more recent development of accompanying kinetic approaches for diffusion serve as excellent examples and are the themes of this symposium. The drivers are, e.g., the development of new materials, processes, and lifetime predictions. Many challenges of the utmost practical importance require long-term fundamental research. This presentation will address some of them, e.g., the effect of various ordering phenomena on activation barriers, and the strength and practical importance of correlation effects.

  • 124171.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Thermodynamics of phase transformations in steels2012In: Phase Transformations in Steels, Elsevier, 2012, Vol. 1, p. 56-93Chapter in book (Refereed)
    Abstract [en]

    The basics of thermodynamics are reviewed with special attention to phase transformations. The distinction between internal and external variables is emphasized and the general equilibrium conditions are derived from the combined first and second law. The concepts of entropy production and driving force as well as stability are discussed. The calculation of thermodynamic properties and phase equilibria is considered and the Calphad method is briefly reviewed, including modeling of substitutional and interstitial disorder. The thermodynamic bases of phase diagrams are examined, and finally, the effect of interfaces, fluctuations and thermodynamics of nucleation are reviewed.

  • 124172.
    Ågren, John
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Brechet, YvesHutchinson, ChristopherPhilibert, JeanPurdy, Gary
    Thermodyanmics and phase transformations: The selected works of Mats Hillert2006Collection (editor) (Other academic)
  • 124173.
    Ågren, John
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Gray, George T. (Rusty), III
    Los Alamos Natl Lab, Los Alamos, NM USA..
    Hwang, Jennie S.
    H Technol Grp, Cleveland, OH USA..
    Matlock, David K.
    Colorado Sch Mines, Golden, CO 80401 USA..
    TODAY'S TECHNOLOGY TRENDS: SHAPING THE FUTURE OF ADVANCED MATERIALS2018In: Advanced Materials and Processes, ISSN 0882-7958, E-ISSN 2161-9425, Vol. 176, no 5, p. 14-17Article in journal (Refereed)
  • 124174.
    Ågren, John
    et al.
    KTH, Superseded Departments, Metallurgy.
    Hayes, F. H.
    Höglund, Lars
    KTH, Superseded Departments, Materials Science and Engineering.
    Kattner, U. R.
    Legendre, B.
    Schmid-Fetzer, R.
    Applications of computational thermodynamics2002In: Zeitschrift für Metallkunde, ISSN 0044-3093, Vol. 93, no 2, p. 128-142Article in journal (Refereed)
    Abstract [en]

    The major tools used in applying computational thermodynamics to various problems in materials science are briefly presented and several practical examples are given as illustrations. Solutions to industrial problems, pertaining to the processing of and microstructure development in several different materials, are shown with answers given in graphical form. Solutions to kinetic problems linked with diffusion are also treated. The last section is devoted to the problem of interfacing between thermodynamic computations and applications oriented software.

  • 124175.
    Ågren, John
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Schmid-Fetzer, Rainer
    True Phase Diagrams2014In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 45A, no 11, p. 4766-4769Article in journal (Refereed)
    Abstract [en]

    With the use of today's computer softwares, phase diagrams can readily be plotted with a wide choice of variables on the axes. Hillert defined a true phase diagram as a diagram where each point uniquely defines the stable phases. He also showed that not all choices of axis variables give true phase diagrams. In this note we will demonstrate that although the rules stated by Hillert are necessary they are not sufficient to have true phase diagrams.

  • 124176.
    Ågren, Jonas
    KTH, Superseded Departments, Geodesy and Photogrammetry.
    Processing of the 1992, 1994 and 1997 Campaigns in the Northen GPS Deformation Traverse2001Licentiate thesis, monograph (Other academic)
    Abstract [en]

    The Northern GPS Deformation Traverse was established to detect movements at two major shear zones now active in northern Sweden, namely the NW trending Bothnian-Senja zone and the N trending Bothnian-Seiland zone. So far three GPS campaigns have been observed the processing of these three campaigns, and to investigate and compare different processing and analysis strategies. It should be noticed that the investigations that are of a purely geodetic nature.

    The campaigns were processed in the Bernese software 4.0 using several different methods. In the first part of the work, more or less the standard method for long baselines described in the Bernese manual (Rothacher, 1996) was applied. In this case all situations in a session were first processed together, using the ionosphere-free linear combination L3, zenith tropospheric parameters, and correct modelling of the correlations. After that, the normal equations from the sessions were analyzed for the baselines between adjacent stations along the traverse, it was found that the results were very bad in the vertical component, the results are more promising in the horizontal, but the different solutions are nevertheless quite noisy. In addition, a few large errors were found also in the horizontal.    

    In the second part of the work, the relatively short individual baselines between adjacent stations were processed separately. The main purpose of this type of processing was to evaluate different processing methods, such as processing with and without zenith tropospheric parameters using either L1 or L2 plus an ionosphere model, and to find out what extent errors caused by antenna-mixing and site dependent effects are present in the data. Another aim was to find out if the baseline mode of processing is suitable for the present project in its own rights. The results show that elevation dependent errors, caused by antenna type mixing and/or site-dependent effects like scattering, are responsible to a considerable degree for the height errors found in the first part. As could be expected, because of the higher noise level for L3, the tests further indicate that the short baselines should be processed without the ionosphere-free linear combination, using for instance L1 and an ionosphere model instead. Also in the horizontal components, considerably better results are obtained in this way.

    In the final part, the campaigns were processed as the first part, but with the difference that L1 and an ionosphere model was used for the shortest baselines, while L3 was applied for the longer ones. The results in the horizontal indicate that the mix of frequencies has worked well. The short baselines are comparable to the best results from the processing of individual baselines, while the accuracy over longer distances is more or less independent of baseline length. At this point we also have investigated how large uncertainly we have because of the method that is used to estimate velocities from the final campaign solutions. Two different methods are compared. The first one is to utilize unweighted linear regression separately for each baseline and telocentric component, while the second is to make a simultaneous adjustment in the horizontal components, using the full cofactor matrices from the final campaign solutions for the weighting. In the latter case, all available correlations are modelled correctly. We conclude that we have significant uncertainties because of the method that is used in this step at the present stage, when only three campaigns are available.      

       

  • 124177.
    Ågren, Jonas
    KTH, Superseded Departments, Infrastructure.
    Regional Geoid Determination Methods for the Era of Satellite Gravimetry: Numerical Investigations Using Synthetic Earth Gravity Models2004Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    It is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. Many, but not all, of these tasks are tested by means of Synthetic Earth Gravity Models (SEGMs). The study is limited to remove-compute-restore methods using Helmert condensation and to Sjöberg's combined approach (method with additive corrections).

    First, a number of modifications of Stokes' formula are tested with respect to their compatibility with a GOCE EGM having negligible commission error. It is concluded that the least squares modification method should be preferred.

    Next, two new point-mass SEGMs are constructed in such a way that the resulting models have degree variances representative for the full and topographically reduced gravity fields, respectively. These SEGMs are then used to test different methods for modified Stokes' integration and downward continuation. It is concluded that the combined method requires dense observations, obtained from the given surface anomalies by interpolation using a reduction for all known density anomalies, most notably the topography. Examples of other conclusions are that the downward continuation method of Sjöberg (2003a) performs well numerically.

    To be able to test topographic corrections, another SEGM is constructed starting from the reduced point-mass model, to which the topography, bathymetry and isostatic compensation are added. This model, which is called the Nordic SEGM, is then applied to test one strict and one more approximate approach to Helmert's condensation. One conclusion here is that Helmert's 1st method with the condensation layer 21 km below sea level should be preferred to Helmert's 2nd condensation strategy.

    The thesis ends with a number of investigations of Sjöberg's combined approach to geoid determination, which include tests using the Nordic SEGM. It is concluded that the method works well in practice for a region like Scandinavia. It is finally shown how the combined strategy may preferably be used to estimate height anomalies directly.

  • 124178.
    Ågren, Jonas
    KTH, Superseded Departments, Alfvén Laboratory.
    The analytical continuation bias in geoid determination using potential coefficients and terrestrial gravity data2004In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 78, no 4-5, p. 314-332Article in journal (Refereed)
    Abstract [en]

    One important application of an Earth Gravity Model (EGM) is to determine the geoid. Since an EGM is represented by an external-type series of spherical harmonics, a biased geoid model is obtained when the EGM is applied inside the masses in continental regions. In order to convert the downward-continued height anomaly to the corresponding geoid undulation, a correction has to be applied for the analytical continuation bias of the geoid height. This technique is here called the geoid bias method. A correction for the geoid bias can also be utilised when an EGM is combined with terrestrial gravity data, using the combined approach to topographic corrections. The geoid bias can be computed either by a strict integral formula, or by means of one or more terms in a binomial expansion. The accuracy of the lowest binomial terms is studied numerically. It is concluded that the first term (of power H-2) can be used with high accuracy up to degree 360 everywhere on Earth. If very high mountains are disregarded, then the use of the H-2 term can be extended up to maximum degrees as high as 1800. It is also shown that the geoid bias method is practically equal to the technique applied by Rapp, which utilises the quasigeoid-to-geoid separation. Another objective is to carefully consider how the combined approach to topographic corrections should be interpreted. This includes investigations of how the above-mentioned H-2 term should be Computed. as well as how it can be improved by a correction for the residual geoid bias. It is concluded that the computation of the combined topographic effect is efficient in the case that the residual geoid bias can be neglected, since the computation of the latter is very time consuming. It is nevertheless important to be able to Compute the residual bias for individual stations. For reasonable maximum degrees, this can be used to check the quality of the H-2 approximation in different situations.

  • 124179.
    Ågren, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics. Lantmäteriet Swedish Mapping, Sweden.
    Engberg, L. E.
    Alm, L.
    Dahlström, F.
    Engfeldt, A.
    Lidberg, M.
    Improving the Swedish quasigeoid by gravity observations on the ice of Lake Vänern2014In: International Association of Geodesy Symposia, 2014, p. 171-177Conference paper (Refereed)
    Abstract [en]

    One of the key activities in Geodesy 2010, the Swedish strategic plan for geodetic activities during the period 2011–2020, is the restoration of the gravity network and data in order to improve the accuracy of the national quasigeoid model. One weak point has been that very few gravity observations have been available over Lake Vänern, Sweden’s largest lake. During the extremely cold winters 2010 and 2011, the ice became sufficiently thick to make ice observation of gravity. The main purpose of this paper is to present the 2011 ice gravity campaign, summarise the experiences made and investigate how much the new ice observations improve the computed quasigeoid model in the area. This is investigated under the assumption that a modern Earth Gravitational Model based on GRACE and GOCE is used. It is found that new ice measurements improve the quasigeoid with a RMS of about 2–3 cm in and around the lake with a maximum improvement of 7 cm.

  • 124180.
    Ågren, Jonas
    et al.
    National Land Survey of Sweden.
    Kiamehr, Ramin
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Sjöberg, Lars Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Numerical comparison of two strategies for geoid and quasi geoid determination over Sweden2007Conference paper (Refereed)
  • 124181.
    Ågren, Jonas
    et al.
    Lantmäteriet (National Land Survey).
    Kiamehr, Ramin
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Sjöberg, Lars Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Progress in the determination of a gravimetric quasigeoid model over Sweden2006Conference paper (Refereed)
    Abstract [en]

    One alternative to the traditional remove-compute-restore procedure that has hitherto been used to compute the Nordic geoid is to use the least squares modification method with additive corrections. This technique, which has been developed at the Royal Institute of Technology (KTH) in Stockholm, includes the least squares kernel modification together with topographic, downward continuation, atmospheric and ellipsoidal corrections.This paper presents the most recent results from an on-going joint project between KTH and Lantmäteriet (National Land Survey of Sweden), whose main purpose is to evaluate the KTH approach numerically and to compute a gravimetric quasigeoid model for Sweden. The work should also be viewed as being conducted under the umbrella of the working group for geoid determination of the Nordic Geodetic Commission (NKG). The evaluation is made using 108 high quality GPS/levelling height anomalies covering the major parts of Sweden except for the mountainous areas to the North West. After a 4-parameter fit, the most promising attempt achieves a RMS value for the residuals of 17 mm, which should be compared to the 28 mm RMS reached by the NKG 2004 model. It is concluded that the least squares modification method with additive corrections is a promising alternative for the future.

  • 124182. Ågren, Jonas
    et al.
    Kiamehr, Ramin
    Zanjan University.
    Sjöberg, Lars Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    The new gravimetric quasigeoid model KTH08 over Sweden2009In: Journal of Applied Geodesy, ISSN 1862-9024, Vol. 3, no 3, p. 143-153Article in journal (Refereed)
    Abstract [en]

    The least squares modification of Stokes formula has been developed in a series of papers published in Journal of Geodesy between 1984 and 2008. It consists of a least squares (stochastic) Stokes kernel modification with additive corrections for the topography, downward continuation, the atmosphere and the ellipsoidal shape of the Earth. The method, developed at the Royal Institute of Technology (KTH) will here be denoted by the abbreviated name the KTH method.

    This paper presents the computational results of a new gravimetric quasigeoid model over Sweden (the KTH08 model) by employing the KTH method. Traditionally the Nordic Geodetic Commission (NKG) has computed gravimetric quasigeoid models over Sweden and other Nordic countries; the latest model being NKG 2004. Another aim of this paper is therefore to compare KTH08 and NKG 2004 quasigeoid models and to evaluate their accuracies using GNSS/levelling height anomalies. The rms fit of KTH08 in 196 GNSS data points distributed over Sweden by using a 1(4)-parameter transformation is 22 (20) mm. It is concluded that KTH08 is a significant step forward compared to NKG 2004.

  • 124183.
    Ågren, Jonas
    et al.
    National Land Survey of Sweden.
    Kiamehr, Ramin
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Sjöberg, Lars Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    The Swedish geoid as evaluated by the method of least-squares modification with additive corrections2006Conference paper (Refereed)
  • 124184.
    Ågren, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Errors in geoid and quasigeoid models as propagated from systematic uncertainties in the Digital Elevation Model2013Conference paper (Refereed)
  • 124185.
    Ågren, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. Lantmäteriet, The Swedish Mapping, Cadastre and Registry Authority, Sweden .
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Investigation of gravity data requirements for a 5 mm-quasigeoid model over Sweden2014In: International Association of Geodesy Symposia, 2014, Vol. 141, p. 143-150Conference paper (Refereed)
    Abstract [en]

    When GNSS height determination improves in the future, users will ask for increasingly better geoid models. It is not unlikely that a standard error of 5 mm will more or less be required in a couple of years. The main purpose of this paper is to investigate the gravity data requirements to compute a Swedish gravimetric quasigeoid model to that order. The propagation of errors in the terrestrial gravity observations and the Earth Gravitational Model (EGM) are studied using both variance-covariance analysis in the spectral domain and least squares collocation. These errors are also checked by computing a new gravimetric quasigeoid model and comparing it with GNSS/levelling height anomalies. It is concluded that it will be possible to compute a 5 mm model over Sweden in the case that the gravity data set is updated to fulfil the following requirements: the resolution should be at least 5 km and there should be no data gaps nearby. Finally, the standard errors of the uncorrelated and correlated gravity anomaly noises should be below 0.5 and 0.1 mGal, respectively.

  • 124186.
    Ågren, Jonas
    et al.
    KTH, Superseded Departments, Infrastructure.
    Sjöberg, Lars Erik
    KTH, Superseded Departments, Infrastructure.
    Comparison of some methods for modifying stokes' formula in the GOCE ERA2004Conference paper (Refereed)
    Abstract [en]

    The dedicated satellite gravity mission GOCE will drastically improve our knowledge of the long to medium wavelengths of the Earth's gravity field. In order to determine the finest details in regional geoid determination, however, we still have to utilise gravity data. It is the purpose of this paper to study three modifications of Stokes' formula numerically, using error propagations with simulated standard errors for the GOCE potential coefficients. The methods tested are the standard remove-compute-restore, the least squares, and the low-degree GOCE-only modifications. In the latter technique it is required that only GOCE information must influence the determination of the lowest degrees. It is concluded that of the modifications tested, the least squares method is most suitable to be used with a GOCE satellite-only model. This is the case also when pessimistic weights are used for the gravity anomalies. The main fault with the standard remove-compute-restore method is its sensitivity to long-wavelength errors in the gravity anomalies, while a very large truncation error is the most serious problem for the low-degree GOCE-only technique.

  • 124187.
    Ågren, Louise
    KTH, School of Biotechnology (BIO).
    Predictive biomarkers for acute graft-versus-host-disease after allogeneic hematopoietic stem cell transplantation: a sixteen patient-donor couple in vitro study2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Allogeneic hematopoietic stem cell transplantation (HSCT) is a widely used medical procedure for treatment of various malignant and non-malignant diseases. However, there are still great risks associated with this treatment. A major complication of allogeneic HSCT is acute graft-versus-host disease (aGvHD). Due to difficulty in treating severe forms of acute GvHD it is desirable to identify predictive markers to assess the risk of patients developing aGvHD. Unfortunately, good biomarkers indicative of acute GvHD remain few. Therefore, the aim of this project is to shed further light on the topic by studying the graft in vitro in hope of finding correlations between expression or secretion of biomarkers and disease progression.

    This study was conducted on sixteen patient-donor couples for allo-HSCT. Post HSCT, the patients were graded with no acute GvHD, grade I or grade II acute GvHD. We looked at markers for T lymphocytes using a mixed lymphocyte reaction (MLR) to analyze how graft cells responded to  irradiated cells from the graft recipient. To this end, we used flow cytometry and Luminex to analyze the reactivity of the donor cells and the correlation of biomarkers with later in vivo development of grade 0 to II of acute GVHD. Ou main finding was a significant decrease (p=0.004) in the cell viability (7-AAD cells) of graft cells for patiens who later developed grade II acute GvHD, compared to patients with no acute GvHD. Overall there were indications of higher frquencies of donor effector T cells for grafts given to patiens who later developed grade II aGvHD. To better assess the correlation between dvelopment of higher stages of acute GvHD and the frequency of different biomarkers more in depth analysis and larger patient groups are needed.

  • 124188.
    Ågren, Niklas
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Advanced Gas Turbine Cycles with Water-Air Mixtures as Working Fluid2000Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Since the early 80's, the worldwide utilization of gas turbines for thermal power generation has increased rapidly. They have less pollution than any other major combustion energy converters. One important development trend in gas turbine technology is new processes for better flue gas heat recovery (gaining better efficiency, power density and environmental impact), so called advanced cycles. The purpose of this work has been to evaluate the performance and process system and subsystems of advanced gas turbine cycles with air/water mixture as working medium. The focus of the thesis is on the evaporative gas turbine cycle. This cycle has extraordinary heat recovery possibilities. An increased understanding of the interaction of the different process components is sought, with an emphasis on modeling the high pressure humidification column. Efforts have been made to synthesize innovative strategies for EvGT humidification. Theoretical and experimental work concerning the water recovery and purification issues are also presented.

    Some important results are that the flow of air through the humidifier should be optimized. For the different cases presented in this thesis, the optimal fraction (with regard to efficiency) varies from about 12% to 40% of the compressor inlet air. Savings in heat exchanger area and reduced pressure work for booster fan are advantages of using only a part of the compressor air in the humidifier. For obtaining best efficiency of the evaporative cycle, the heat flows above the boiling point should preferably be taken care of by conventional boilers for steam injection or by a separate humidifier section working only slightly below boiling temperature. This is particularly important in gas turbines without intercooling or without recuperation due to high temperatures in exit streams. The unique nature of the humidifier is its ability to evaporate water below the boiling point, by the use of air dilution. However, the best temperature performance (lowest temperature of outlet water from humidifier) is reached if the thermal loading on the humidifier is not excessive.

    The need for large quantities of demineralized water has previously been identified as a possible drawback for the EvGT cycle. In favor of the EvGT-technology, the first water testing experiments on a pilot EvGT-plant, presented in this work, contradict this notion. It is theoretically and experimentally shown that an EvGT-plant can be run with no external water feed at all, by means off lue gas condensation and condensate recovery. After internal condensate treatment, the recycled condensate was of equal quality or better than the deionized fresh feed used for initial system fill-up.

  • 124189.
    Ågren, Niklas
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Simulation and design of advanced air-water mixture gas turbine cycles1997Licentiate thesis, comprehensive summary (Other scientific)
  • 124190. Ågren, O.
    et al.
    Moiseenko, V. E.
    Noack, K.
    Hagnestal, A.
    Kallne, J.
    Anglart, Henryk
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Hybrid Reactor Studies Based On The Straight Field Line Mirror2013In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 63, no 1T, p. 52-57Article in journal (Refereed)
    Abstract [en]

    The straight field line mirror (SFLM) hybrid reactor studies aim to identify a concept where the safety of fission power production could be enhanced. A fusion neutron source could become a mean to achieve this. The SFLM studies address critical issues such as reactor safety, natural circulation of coolants, steady state operation for a year or more and means to avoid too strong material loads by a proper geometrical arrangement of the reactor components. A key result is that power production may be possible with a fusion Q factor as low as 0.15. This possibility arises from the high power amplification by fission, which within reactor safety margins may exceed a factor of 100. The requirements on electron temperature are dramatically lower for a fusion hybrid compared to a stand-alone fusion reactor. This and several other factors are important for our choice to select a mirror machine for the fusion hybrid reactor studies.

  • 124191. Ågren, O.
    et al.
    Moiseenko, V. E.
    Noack, K.
    Hagnestål, A.
    Källne, J.
    Anglart, Henryk
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    The straight field line mirror concept aiming at a hybrid reactor2012In: 39th EPS Conference on Plasma Physics 2012, EPS 2012 and the 16th International Congress on Plasma Physics: Volume 1, 2012, 2012, p. 5-8Conference paper (Refereed)
  • 124192. Ågren, O.
    et al.
    Noack, K.
    Moiseenko, V. E.
    Hagnestål, A.
    Källne, J.
    Anglart, Henryk
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    The hybrid reactor project based on the straight field line mirror concept2012In: Fusion For Neutrons And Subcritical Nuclear Fission / [ed] Kallne, J; Ryutov, D; Gorini, G; Sozzi, C; Tardocchi, M, American Institute of Physics (AIP), 2012, p. 173-185Conference paper (Refereed)
    Abstract [en]

    The straight field line mirror (SFLM) concept is aiming towards a steady-state compact fusion neutron source. Besides the possibility for steady state operation for a year or more, the geometry is chosen to avoid high loads on materials and plasma facing components. A comparatively small fusion hybrid device with "semi-poor" plasma confinement (with a low fusion Q factor) may be developed for industrial transmutation and energy production from spent nuclear fuel. This opportunity arises from a large fission to fusion energy multiplication ratio, Qr=Pfis/P fus>>1. The upper bound on Qr is primarily determined by geometry and reactor safety. For the SFLM, the upper bound is Qr≈150, corresponding to a neutron multiplicity of k eff=0.97. Power production in a mirror hybrid is predicted for a substantially lower electron temperature than the requirement T e≈10 keV for a fusion reactor. Power production in the SFLM seems possible with Q≈0.15, which is 10 times lower than typically anticipated for hybrids (and 100 times smaller than required for a fusion reactor). This relaxes plasma confinement demands, and broadens the range for use of plasmas with supra-thermal ions in hybrid reactors. The SFLM concept is based on a mirror machine stabilized by qudrupolar magnetic fields and large expander tanks beyond the confinement region. The purpose of the expander tanks is to distribute axial plasma loss flow over a sufficiently large area so that the receiving plates can withstand the heat. Plasma stability is not relying on a plasma flow into the expander regions. With a suppressed plasma flow into the expander tanks, a possibility arise for higher electron temperature. A brief presentation will be given on basic theory for the SFLM with plasma stability and electron temperature issues, RF heating computations with sloshing ion formation, neutron transport computations with reactor safety margins and material load estimates, magnetic coil designs as well as a discussion on the implications of the geometry for possible diagnostics. Reactor safety issues are addressed and a vertical orientation of the device could assist passive coolant circulation. Specific attention is put to a device with a 25 m long confinement region and 40 cm plasma radius in the mid-plane. In an optimal case (keff = 0.97) with a fusion power of only 10 MW, such a device may be capable of producing a power of 1.5 GWth.

  • 124193.
    Ågren, Peter
    KTH, Superseded Departments, Physics.
    Charging effects in small capacitance Josephson junction circuits2002Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis describes fabrication, measurements and analysisof two different Josephson junction circuits; the Cooper pairtransistor (CPT) and the one dimensional Josephson junctionarray (JJA). All experiments are conducted in a dilutionrefrigerator with a base temperature of 15{30 mK.In the experiments on CPTs the maximum supercurrent,called the switch- ing current, is measured versus the gatecharge. The importance of filtering of the measurement leads inorder to suppress quasi-particle excitations and to get2e-periodic switching currents is demonstrated. Normal metalgold leads close to the CPTs are introduced to further reducethe effect of quasi-particles. To prove that switching currentis 2e-periodic, magnetic fields and increased temperatures areused to induce a transition to e-periodicity. CPTs where eachJosephson junction is replaced by a Superconducting QuantumInterference de- vice (SQUID) have also been fabricated andmeasured. The SQUIDs make it possible to tune the effectiveJosephson energy with an external magnetic field. The measuredswitching current is tunable in magnitude and 2e-periodic. Theswitching currents are compared with theory. Good agreementbetween the- ory and experiments is found using a model of theCPT in an electrodynamic environment with a high effectivetemperature.The JJAs are also fabricated with a SQUID geometry toenable tuning of the effective Josephson energy. The currentvoltage characteristics (IVCs) of the measured JJAs exhibit aCoulomb blockade of Cooper pair tunneling which is tunable withmagnetic field and periodic with the ux quanta. The IVCs of theJJA show a region of negative differential resistance, alsocalled back- bending. This is interpreted as evidence of Blochoscillations in the JJAs. Two different models are discussed toexplain the measured IVC.The thesis ends by presenting a theoretical proposal ona Josephson junction charge qubit, called the array-qubit. Thearray-qubit consists of an array with N SQUIDs and N +1islands. The two basis states of the qubit corresponds to anexcess Cooper pair on either island 1 or N +1. These two statesare coupled through an Nth-order tunneling process which makesit possible to effectively suppress the Josephson coupling.This facilitate a long relaxation time so that the state of thequbit can be read with a slow detector.

  • 124194.
    Ågren, Peter
    KTH, Superseded Departments, Physics.
    Cooper pair transport and Coulomb blockade in one dimensional Josephson arrays2000Licentiate thesis, comprehensive summary (Other scientific)
  • 124195.
    Ågren, Peter
    et al.
    KTH, Superseded Departments, Physics.
    Walter, Jochen
    KTH, School of Engineering Sciences (SCI), Physics.
    Haviland, David B.
    KTH, Superseded Departments, Physics.
    Switching Current of a Cooper Pair Transistor with Tunable Josephson Junctions2002In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 66, no 1, p. 14510-Article in journal (Refereed)
    Abstract [en]

    We investigate the switching current of a Cooper pair transistor with tunable Josephson energy. The junctions are fabricated in a superconducting quantum interference device (SQUID) geometry which allows for an in situ tunable effective Josephson energy by application of a magnetic field. We find a 2e-periodic switching current versus gate charge. As the magnetic field is increased the switching current stays 2e-periodic but the magnitude is suppressed. At a magnetic field of half a flux quantum through the SQUID's the switching current is minimum. We can theoretically model the experimental data by assuming a switching current which is proportional to the ideal critical current squarred. We show that such a dependence is expected in the limit where the effect of thermal fluctuations on the system is strong.

  • 124196.
    Ågren, Peter
    et al.
    KTH, Superseded Departments, Physics.
    Walter, Jochen
    KTH, School of Engineering Sciences (SCI), Physics.
    Schöllmann, Volker
    KTH, School of Engineering Sciences (SCI), Physics.
    Haviland, David B.
    KTH, Superseded Departments, Physics.
    Switching Currents and Quasi-Particle Poisoning in the Superconducting Single Electron Transistor2002In: INTERNATIONAL WORKSHOP ON SUPERCONDUCTING NANO-ELECTRONICS DEVICES, 2002, p. 25-31Conference paper (Refereed)
  • 124197. Ågren, Rasmus
    et al.
    Mardinoglu, Adil
    Asplund, Anna
    Kampf, Caroline
    Uhlén, Mathias
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Nielsen, Jens
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Identification of anticancer drugs for hepatocellular carcinoma through personalized genome-scale metabolic modeling2014In: Molecular Systems Biology, ISSN 1744-4292, E-ISSN 1744-4292, Vol. 10, no 3, p. A721-Article in journal (Refereed)
    Abstract [en]

    Synopsis image Personalized GEMs for six hepatocellular carcinoma patients are reconstructed using proteomics data and a task-driven model reconstruction algorithm. These GEMs are used to predict antimetabolites preventing tumor growth in all patients or in individual patients. The presence of proteins encoded by 15,841 genes in tumors from 27 HCC patients is evaluated by immunohistochemistry. Personalized GEMs for six HCC patients and GEMs for 83 healthy cell types are reconstructed based on HMR 2.0 and the tINIT algorithm for task-driven model reconstruction. 101 antimetabolites are predicted to inhibit tumor growth in all patients. Antimetabolite toxicity is tested using the 83 cell type-specific GEMs. An l-carnitine analog inhibits the proliferation of HepG2 cells. Abstract Genome-scale metabolic models (GEMs) have proven useful as scaffolds for the integration of omics data for understanding the genotype-phenotype relationship in a mechanistic manner. Here, we evaluated the presence/absence of proteins encoded by 15,841 genes in 27 hepatocellular carcinoma (HCC) patients using immunohistochemistry. We used this information to reconstruct personalized GEMs for six HCC patients based on the proteomics data, HMR 2.0, and a task-driven model reconstruction algorithm (tINIT). The personalized GEMs were employed to identify anticancer drugs using the concept of antimetabolites; i.e., drugs that are structural analogs to metabolites. The toxicity of each antimetabolite was predicted by assessing the in silico functionality of 83 healthy cell type-specific GEMs, which were also reconstructed with the tINIT algorithm. We predicted 101 antimetabolites that could be effective in preventing tumor growth in all HCC patients, and 46 antimetabolites which were specific to individual patients. Twenty-two of the 101 predicted antimetabolites have already been used in different cancer treatment strategies, while the remaining antimetabolites represent new potential drugs. Finally, one of the identified targets was validated experimentally, and it was confirmed to attenuate growth of the HepG2 cell line.

  • 124198.
    Åhlander Cevallos, Viktor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Åström, Henrik
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Individual metering and charging of heat and hot water in row house areas - Comparing study of two row house areas in Stockholm2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today’s society our residents and premises consume 38 % of the total energy use in Sweden. 2011 that number corresponded to 77,8 TWh/year. Governments and the public’s strive to lower the energy use and the European Union’s goal that all member countries should lower their energy consumption with 20 % until year 2020 creates incentives to renovations and energy efficiency measures.

    A possible measure that could lead to reduced energy consumption for rental apartments and smaller residences like row-houses is to install individual metering. Individual metering is a method to measure how much energy is consumed in residences. Devices are installed in homes and can measure the water and heat consumption and let the residence pay for what is actually used.

    In this report the consumption and the costs for heat and warm water and the attitude to individual metering between two row-house areas is investigated. Both areas are located in Stockholm, in Huddinge and Farsta, where one of the areas has installed individual metering.

    Our study shows difference of the consumption and costs between the two areas. The installation of individual metering has result in a higher awareness for the people living in that area which has led to a reduced consumption and cost. The attitude for individual metering is positive in both areas and unchanged after the installation of individual metering.

  • 124199.
    Åhlander, Gunnar
    KTH, Superseded Departments, Civil and Architectural Engineering.
    The air distribution in buildings with combined natural and mechanical ventilation2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This work describes result from both measurements on anumber of one family houses, an analytical study of a one-zonemodel and multi zone studies of a two storey building. Thesimulations are performed as both parametric studies, withcombined values of outside temperature, wind velocity and winddirection, and whole year simulations. For the latter, aclimate file for the northern Swedish city Östersund isused.

    The results, for the whole year simulations, are presentedas ventilation availabilities. The ventilation availability isdefined as the relative time of the heating season during whicha specified airflow is exceeded. This specified airflow maye.g. be a Building Code requirement if such exists.

    The influence of different measures, and combinations ofmeasures, on the ventilation availability has been determinedfor the different rooms. It is found that acceptableventilation availability is possibly to achieve with naturalventilation. However, it requires large supply and overflowopenings and extended ventilation chimneys. These chimneys maybe difficult to accept from an esthetical point of view. Thenatural system is also very sensitive for changes in winddirection.

    To ensure required airflows at all times, an exhaust orhybrid ventilation system may be necessary.

    Some recommendations may be based on this study.

    -Consider the predominating wind direction. It’san advantage to have more supply openings on the leeward side,i.e. to place“humid”rooms towards the knownwindward side.-Use different chimney heights from the different“humid”rooms, to balance the internal airflows. Ifmechanical exhaust is used, it may be used only from some ofthe“humid”rooms, preferable the ones with closeddoors.-Use as large supply and overflow openings aspossible. Different opening areas may be used to balance theairflows, especially if the predominating wind direction isknown. Acoustic problems may be a limiting factor for theopening area. There may also exist a maximum opening area abovewhich stability problems occur.-Construct ventilation chimneys and chimney outlets ina way, that the windgenerated pressure at the outlet is alwaysnegative and independent of wind direction. Insulate thechimneys to avoid cooling of the air and decreased buoyancyforces.

    -Use different chimney heights from the different“humid”rooms, to balance the internal airflows. Ifmechanical exhaust is used, it may be used only from some ofthe“humid”rooms, preferable the ones with closeddoors.

    -Use as large supply and overflow openings aspossible. Different opening areas may be used to balance theairflows, especially if the predominating wind direction isknown. Acoustic problems may be a limiting factor for theopening area. There may also exist a maximum opening area abovewhich stability problems occur.

    -Construct ventilation chimneys and chimney outlets ina way, that the windgenerated pressure at the outlet is alwaysnegative and independent of wind direction. Insulate thechimneys to avoid cooling of the air and decreased buoyancyforces.

  • 124200.
    Åhlander Pettersson, Victoria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Mattsson, Anton
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Kartläggning av problem vid projektering, installation och drift av värmepumpar2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to be able to perform energy efficiency measures in an existing building, and generate a good outcome, good knowledge of the project is required. This means that all disciplines must have a good cooperation and that each discipline must take responsibility for the task. It is not always that the outcome will be optimal. A summary in tabular form can clearly identify the frequent problems. This is done by highlighting the problems that arise in connection with the design, installation and operation of heat pumps in three different cases, generating a compiled table. The result shows that eight different problems occur and all results are explained and analyzed. By detecting weaknesses, and suggesting possible measures, problems with the design, installation and operation of heat pumps may decrease.

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