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  • 16651.
    Bremberg, Ulf
    KTH, Superseded Departments, Chemistry.
    Asymmetric catalysis: ligand design and microwave acceleration2000Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis deals partly with the design and synthesis ofligands for use in asymmetric catalysis, and partly with theapplication of microwave heating on metal-based asymmetriccatalytic reactions.

    Enantiomerically pure pyridyl alcohols and bipyridylalcohols were synthesized from the chiral pool for future usein asymmetric catalysis. Lithiated pyridines were reacted withseveral chiral electrophiles, yielding diastereomeric mixturesthat could be separated without the use of resolutiontechniques.

    New pyridino- and quinolinooxazolines were synthesized andtested in palladium-catalyzed asymmetric allylation using1,3-diphenyl-2-propenyl acetate and dimethyl malonate. Theconformational preferences of the ligands in palladiumcomplexes were studied with crystallography, 2D-NMR techniquesand DFT calculations. Conclusions about how the chirality wastransferred from the ligand to the substrate could be drawnfrom the conformational analysis.

    The effect of heating Pd- and Mo-catalyzed asymmetricallylic substitution reactions was investigated with oil bathheating and microwave irradiation. With a few exceptions,ligands with high room temperature selectivity were shown toretain their selectivity on heating. Reaction rates, catalyststability and product selectivities of microwave-heatedreactions were compared with those of reactions performed inoil bath.

    Palladium-catalyzed asymmetric allylation was studied withseveral ligand types, allylic substrates and nucleophiles. Someof the experimental procedures had to be adapted to microwaveheating conditions.

    The procedure for asymmetric allylation catalyzed bybispyridylamide molybdenum complexes was developed into aone-pot microwave-mediated reaction. With microwaves, Mo(CO)6could be used as an easily-handled metal sourceand inert conditions could be omitted. Derivatives of thebispyridylamide ligandswere synthesized and tested withmolybdenum as catalysts to investigate the effects ofsubstituents on the pyridine ring.

    Keywords: ligand, asymmetric catalysis, pyridylalcohols, oxazolines, conformational study, Pd-allyl, fastchemistry, microwave chemistry, Mo-allyl, bispyridylamides.

  • 16652.
    Bremer, Einar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Landemoo, Viktor
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Mechanisms for rear wheelsteering on a Formula Student car2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis the requirements for a rear wheel steering mechanism aimed to be implementedon KTH:s Formula Student car were evaluated. The requirements were obtainedby using already known loads, an analysis of how the quickly the driver turns the steeringwheel during track driving from video material and the Formula Student rulebook whichthe car is designed after. After the requirements were produced a number of concepts wereproduced and evaluated against each other. The concept that was given the highest scorewas a rack and pinion concept with a rotary actuator which was developed further.The design was made by first selecting an actuator with a planetary gearbox that couldfulfill the speed and load requirements and afterwards with CAD a design that could beintegrated on the car was made. The concept weighed around 1,7 kg and was compatiblewith the requirements.

  • 16653.
    Bremer, Hanna D.
    et al.
    Swedish Univ Agr Sci, Dept Clin Sci, SE-75007 Uppsala, Sweden..
    Landegren, Nils
    Karolinska Inst, Karolinska Univ Hosp, Dept Med Solna, CMM, L8 01, SE-17176 Stockholm, Sweden.;Uppsala Univ, Dept Med Sci, Sci Life Lab, Uppsala, Sweden..
    Sjöberg, Ronald
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Hallgren, Asa
    Karolinska Inst, Karolinska Univ Hosp, Dept Med Solna, CMM, L8 01, SE-17176 Stockholm, Sweden..
    Renneker, Stefanie
    Euroimmun AG, D-23560 Lubeck, Germany..
    Lattwein, Erik
    Euroimmun AG, D-23560 Lubeck, Germany..
    Leonard, Dag
    Uppsala Univ, Rheumatol & Sci Life Lab, Dept Med Sci, SE-75185 Uppsala, Sweden..
    Eloranta, Maija-Leena
    Uppsala Univ, Rheumatol & Sci Life Lab, Dept Med Sci, SE-75185 Uppsala, Sweden..
    Ronnblom, Lars
    Uppsala Univ, Rheumatol & Sci Life Lab, Dept Med Sci, SE-75185 Uppsala, Sweden..
    Nordmark, Gunnel
    Uppsala Univ, Rheumatol & Sci Life Lab, Dept Med Sci, SE-75185 Uppsala, Sweden..
    Nilsson, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics.
    Andersson, Goran
    Swedish Univ Agr Sci, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden..
    Lilliehook, Inger
    Swedish Univ Agr Sci, Dept Clin Sci, SE-75007 Uppsala, Sweden..
    Lindblad-Toh, Kerstin
    Broad Inst Harvard & MIT, Cambridge, MA 02142 USA.;Uppsala Univ, Sci Life Lab, IMBIM, SE-75123 Uppsala, Sweden..
    Kampe, Olle
    Karolinska Inst, Karolinska Univ Hosp, Dept Med Solna, CMM, L8 01, SE-17176 Stockholm, Sweden.;Uppsala Univ, Dept Med Sci, Sci Life Lab, Uppsala, Sweden.;Univ Bergen, Dept Clin Sci, N-5021 Bergen, Norway.;Univ Bergen, KG Jebsen Ctr Autoimmune Disorders, N-5021 Bergen, Norway.;Haukeland Hosp, Dept Med, N-5021 Bergen, Norway..
    Hansson-Hamlin, Helene
    Swedish Univ Agr Sci, Dept Clin Sci, SE-75007 Uppsala, Sweden..
    ILF2 and ILF3 are autoantigens in canine systemic autoimmune disease2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 4852Article in journal (Refereed)
    Abstract [en]

    Dogs can spontaneously develop complex systemic autoimmune disorders, with similarities to human autoimmune disease. Autoantibodies directed at self-antigens are a key feature of these autoimmune diseases. Here we report the identification of interleukin enhancer-binding factors 2 and 3 (ILF2 and ILF3) as autoantigens in canine immune-mediated rheumatic disease. The ILF2 autoantibodies were discovered in a small, selected canine cohort through the use of human protein arrays; a method not previously described in dogs. Subsequently, ILF3 autoantibodies were also identified in the same cohort. The results were validated with an independent method in a larger cohort of dogs. ILF2 and ILF3 autoantibodies were found exclusively, and at a high frequency, in dogs that showed a speckled pattern of antinuclear antibodies on immunofluorescence. ILF2 and ILF3 autoantibodies were also found at low frequency in human patients with SLE and Sjogren's syndrome. These autoantibodies have the potential to be used as diagnostic biomarkers for canine, and possibly also human, autoimmune disease.

  • 16654.
    Bremer, Lisa
    KTH, School of Biotechnology (BIO).
    Hyaluronan (HA) fragments as initiators or enhancers of inflammation in arthritis2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 16655.
    Bremer, Lucas
    KTH, School of Biotechnology (BIO).
    Designing and characterising a dual format antigen protein microarray for autoimmune profiling2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 16656.
    Bremer, Matthias
    KTH, School of Engineering Sciences (SCI), Physics.
    Periodically Poled RidgeWaveguides in LiNbO32012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 16657.
    Bremer, Timur
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Silfverhielm, Alexandra
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Autoklavtillverkning - med analys och förbättringar2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 16658.
    Bremmer, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Sjöblom, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Minor Field Study for the International Finance Corporation (IFC) and the Worldbank Group: Investment conditions for a bio-fuel pellet production in Bolivia contributing to an improved and sustainable indigenous forestry2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report presents the findings from a Minor Field Study aimed to describe the preconditions for an investment in large-scale Bolivian production of wood pellets for export contributing to an imrpoved and sustainable indigenous forestry. The study was carried out on behalf of the International Finance Corporation, IFC, a member of the World Bank Group that promotes sustainable private sector investment in developing countires as a way to reduce poverty and improve poeple´s lives.

    Wood pellets are dried biomass processed into an easily combustible pellet form that offers a renewable and carbon neutral fuel source with higher energy density and more efficient transport properties than most traditional biomass energy sources. The global demand for pellets is strong and predicted to grow by over 25% per year until 2020. Bolivia is a country rich in natural resources with over 53,6 million ha of forest. But despite both the natural resources and a global demand for forest products Bolivian forest exports are very low. At the same time the large indigenous population, who possesses large unexploited land and forest is very poor and lack work. A large-scale  investment in a pellet production seems to have the potential of increasing Bolivian forestry export and thus improve the living conditions for indigenous.

    By the means of a field study in the Bolivian forestry sector and researching literature and scientific reports this project has tried to create a business case analyzing the preconditions in Bolivia in a way that is relevant for a potential commercial investor. The work has resultes in a business case analyzing three major segments; the global wood pellet market, Bolivia on a national level and finally the Bolivian forestry sector on an more detailed level including a cost estimation for a potential pellet plant. The study finds that while Bolivia offers investors great opportunities with large forest reservs and vacant land for plantations in combination with a beneficial legislation. However, important weaknesses are the complicated business climate, small and fragmented wood supply and costly and complicated transportation. The study identifies three urgent and prioritized issues in the Bolivian forestry sector and suggest next steps to take in order to face the challenges. Furhter the study concludes that in order to be able to serve as a major supplier of wood the indigenous actors will have to be organized on an aggregated and commercial level. The organization would need long-term involvement of a commercial actor to train, equip and bring together the indigenous sppliers. If done successfully the indigenous groups could benefit from being a supplier with access to an international, fast growing market without having to masterinternational business. This can in turn lead to increased sustainable wealth with new job opportunities and improved social conditions. The study also suggests that indigenous groups could profit from new forest plantation on their fallow land while it also would bring improved environmental conditions, increased wood supply with facilitated extraction and higher productivity.

  • 16659.
    Bremstedt Pedersen, Ivan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Andersson, Alfred
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    More than downloading: Visualization of data produced by sensors in a home environment2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A home automation system usually contains a set of tools that users use to control devices in their homes, often remotely. These devices often include but are not limited to light switches, thermostats, thermometers, window blinds, and climate controls. The potential for these kinds of systems is huge because of the sheer number of devices that could be controlled and managed with minimal and inexpensive extra hardware. Many of the appliances in a normal home could benefit from being connected to a system that allows the owner to manage and control the devices in their home. Thus the number of potential devices is orders of magnitude larger than the number of homes connected to the system. There are several systems on the market that provide systems to monitor and control a home environment, however these systems only support specific in system devices. This uncovers a problem where a homeowner only has the opportunity to use specific products that fit into these systems. By introducing an open platform for the public that are not bound to any system we can allow more devices to be integrated in the home and contribute to further development of smarter homes.

    The goal with this project was to provide a scalable open platform with the possibility of asynchronous updating. This has been done by implementing multiple logical parts to both provide a web interface for the user and to allow us to handle communication and storage of data. All these parts are linked together to form a system of servers that handles all background operations. This thesis discusses and presents implementations of all of these servers, how they are implemented, communicate with each other, provide secure connections and how they can scale with increasing usage. In this process we also discuss and present techniques that were used, how to use them and their benefits, to help us reach our goal.

  • 16660.
    Bremström, Maria
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Stipic, Susanne
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Återtillverkning av fordonskomponenter: En komparativ studie av den svenska marknaden2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The linear “take-make-dispose” production process has long been the dominating form of production. This production model is dependent on a steady supply of raw material that is processed into goods, which are then consumed and discarded. However, the dwindling raw material reserves are causing sustainable production processes to become more important for producers, resulting in the emergence of various methods for reusing materials and discarded products. This is especially noticeable in the automotive industry. Remanufacturing, the process of restoring a discarded product to its original state, is a growing area of interest for both original equipment manufacturers and independent remanufacturers. The objective of this report was to evaluate remanufacturing of automotive components on the Swedish market. This was done by surveying companies related to remanufacturing. A comparative study of two remanufacturers, Volvo Powertrain in Flen and Borg Automotive, was also performed. Additionally, the remanufacturing difficulties found in theory were compared to the difficulties expressed by the surveyed remanufacturers. The result of this project showed that remanufacturing is not a widespread practice in Sweden. However, the surveyed companies have a positive attitude towards remanufacturing and consider it to be a growing industry. The obstacles for remanufacturing found in theory were found to be valid in practice. These obstacles are inventory build-up, insufficient access to discarded components, and difficulties automating the remanufacturing process. The operations of original equipment remanufacturers and independent remanufacturers were found to differ from one another and therefore the companies face different types of obstacles. Moreover, high barriers to entry make it difficult for new companies to emerge on the market. There are also weak legal incentives for companies to start remanufacturing. Instead remanufacturers are primarily driven by financial incentives. Another obstacle, not identified in the theoretical framework and experienced by the original equipment remanufacturers, is the matching of supply and demand. In conclusion, the theoretical framework is largely consistent with the observed practice. This indicates the remanufacturing is well understood in the academic literature. The problem of matching supply and demand should be examined more closely in future studies, as there is no theoretical foundation for this problem. Overall, there is a positive outlook on remanufacturing and the companies involved work actively to both promote remanufacturing as a practice and develop solutions for the problems they face.

  • 16661.
    Brena, Barbara
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    First principles modeling of soft X-ray spectroscopy of complex systems2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The electronic structures of complex systems have been studied by theoretical calculations of soft x-ray spectroscopies like x-ray photoelectron spectroscopy, near edge x-ray absorption fine structure, and x-ray emission spectroscopies. A new approach based on time dependent density functional theory has been developed for the calculation of shake-up satellites associated with photoelectron spectra. This method has been applied to the phthalocyanine molecule, describing in detail its electronic structure, and revealing the origin of controversial experimental features. It is illustrated in this thesis that the theoretical intepretation plays a fundamental role in the full understanding of experimental spectra of large and complex molecular systems. Soft x-ray spectroscopies and valence band photoelectron spectroscopies have proved to be powerful tools for isomer identification, in the study of newly synthesized fullerene molecules, the azafullerene C48N12 and the C50Cl10 molecule, as well as for the determination of the conformational changes in the polymeric chain of poly(ethylene oxide). The dynamics of the core excitation process, revealed by the vibrational fine structure of the absorption resonances, has been studied by means of density functional and transition state theory approaches.

  • 16662.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Carniato, S.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Functional and basis set dependence of K-edge shake-up spectra of molecules2005In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 122, no 18, p. 184316-Article in journal (Refereed)
    Abstract [en]

    A straightforward approach for computing the K -edge shake-up spectra of molecules based on equivalent core-hole linear response theory at both Hartree-Fock and density functional theory levels is proposed. Benchmark calculations have been performed to explore its sensitivity to different types of functionals and basis sets for the carbon 1s shake-up spectra of benzene and metal-free phthalocyanine (H2 Pc). A very good agreement with previous theoretical and experimental works for the benzene molecule has been obtained for all the functionals and basis sets tested. Electron correlation is found to be essential for a good description of the H2 Pc system, whose experimental C 1s shake-up spectrum is best reproduced by the hybrid density functional.

  • 16663.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Carniato, Stéphane
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Electronic and geometrical structures of the N1s-13(pi) excited states in the N2O moleculeManuscript (preprint) (Other academic)
  • 16664.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Characterization of the electronic structure of C50Cl10 by means of soft x-ray spectroscopies2005In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 123, no 24, p. 244305-1-244305-4Article in journal (Refereed)
    Abstract [en]

    The electronic structure of the last synthesized fullerene molecule, the C50Cl10, has been characterized by theoretical simulation of x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and near-edge x-ray-absorption fine structure. All the calculations were performed at the gradient-corrected and hybrid density-functional theory levels. The combination of these techniques provides detailed information about the valence band and the unoccupied molecular orbitals, as well as about the carbon core orbitals.

  • 16665.
    Brena, Barbara
    et al.
    KTH, Superseded Departments, Biotechnology.
    Luo, Yi
    KTH, Superseded Departments, Biotechnology.
    Electronic structures of azafullerene C48N122003In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 119, no 14, p. 7139-7144Article in journal (Refereed)
    Abstract [en]

    Two recently proposed low-energy azafullerene C48N12 isomers have been theoretically characterized using x-ray spectroscopies. The x-ray photoelectron spectroscopy, the near-edge absorption fine structure, the x-ray emission spectroscopy, and the ultraviolet photoelectron spectroscopy for both isomers have been predicted at the gradient-corrected density functional theory level. These spectroscopies together give a comprehensive insight of the electronic structure on the core, valence, and unoccupied orbitals. They have also provided a convincing way for identifying the isomer structures.

  • 16666.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Time-dependent DFT calculations of core electron shake-up states of metal-(free)-phthalocyanines2006In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 75, no 11, p. 1578-1581Article in journal (Refereed)
    Abstract [en]

    We have introduced a new approach for the calculation of the shake-up structures of molecular photoelectron spectra, based on the combination of time-dependent density functional theory (TD-DFT) and equivalent core hole (or Z + 1) approximation. The method, suitable for large molecules, has been applied to compute the complex shake-up states associated with the carbon Is X-ray photoelectron spectroscopy (XPS) of metal-free and nickel phthalocyanines (H2Pc and NiPc, respectively). A similar satellite profile emerges for both molecules.

  • 16667.
    Brena, Barbara
    et al.
    KTH, Superseded Departments, Biotechnology.
    Luo, Yi
    KTH, Superseded Departments, Biotechnology.
    Nyberg, Mats
    KTH, Superseded Departments, Biotechnology.
    Puglia, C.
    et al.,
    Equivalent core-hole time-dependent density functional theory calculations of carbon 1s shake-up states of phthalocyanine2004In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 70, no 19, p. 195214-Article in journal (Refereed)
    Abstract [en]

    The shake-up transition energies of the carbon 1s photoelectron spectrum of metal-free phthalocyanine (H2Pc) have been calculated by means of time-dependent density functional theory, for which an equivalent core approximation is adopted. Model calculations for the C 1s shake-up states of benzene are in excellent agreement with the latest experimental results. The complex C 1s shake-up structures associated with the aromatic and pyrrole carbons in the phthalocyanine are computed, as well as their ionization potentials. They allow us to determine the origin of the anomalous intensity ratio between the pyrrole and benzene carbons in a high resolution C 1s photoelectron spectrum measured for a H2Pc film, as due to a benzene-related shake-up contribution, hidden under the pyrrole main intensity feature.

  • 16668.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Nordlund, D
    Odelius, M
    Ogasawara, H
    Nilsson, A
    Pettersson, L G M
    Ultrafast molecular dissociation of water in ice2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 14, p. 148302-Article in journal (Refereed)
    Abstract [en]

    Using x-ray emission and photoemission spectroscopies to measure the occupied valence levels in a thin crystalline ice film, we resolve the ionization-induced dissociation of water in ice on a femtosecond time scale. Isotope substitution confirms proton transfer during the core-hole lifetime in spite of the nonresonant excitation. Through ab initio molecular dynamics on the core-ionized state, the dissociation and spectrum evolution are followed at femtosecond intervals. The theoretical simulations confirm the experimental analysis and allow for a detailed study of the dissociative reaction path.

  • 16669.
    Brena, Barbara
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Palmgren, Pål
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Nilson, Katharina
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Yu, Shun
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Hennies, F.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Agnarsson, Björn
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Önsten, Anneli
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Månsson, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    InSb-TiOPc interfaces: Band alignment, ordering and structure dependent HOMO splitting2009In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 603, no 20, p. 3160-3169Article in journal (Refereed)
    Abstract [en]

    Thin films of titanyl phthalocyanine (TiOPc) have been adsorbed on InSb(1 1 1) (3 x 3) and InSb(1 0 0) c(8 x 2) surfaces and studied with respect to their electronic structure using photoemission (PES), density functional theory (DFT) and scanning tunneling microscopy (STM). The interface chemical interaction is weak in both cases; no adsorbate induced surface band bending is observed and the energy level alignment across the interface is determined by the original position of the substrate Fermi level and the charge neutrality level of the molecule. Room temperature adsorption results in disordered films on both surfaces. The behaviors after annealing are different; on InSb(1 0 0) well-ordered molecular chains form along and on top of the In-rows, whereas on (1 1 1) no long range order is observed. The disorder leads to intermolecular interactions between the titanyl group and neighboring benzene rings leading to a split of TiOPc HOMO (highest occupied molecular orbital) by as much as 0.8 eV.

  • 16670. Brena, Barbara
    et al.
    Siegbahn, Per E. M.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Modeling Near-Edge Fine Structure X-ray Spectra of the Manganese Catalytic Site for Water Oxidation in Photosystem II2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 41, p. 17157-17167Article in journal (Refereed)
    Abstract [en]

    The Mn Is near-edge absorption fine structure (NEXAFS) has been computed by means of transition-state gradient-corrected density functional theory (DFT) on four Mn4Ca clusters modeling the successive S-0 to S-3 steps of the oxygen-evolving complex (OEC) in photosystem II (PSII). The model clusters were obtained from a previous theoretical study where they were determined by energy minimization. They are composed of Mn(III) and Mn(IV) atoms, progressing from Mn(III)(3)Mn(IV) for S-0 to Mn(III)(2)Mn(IV)(2) for S-1 to Mn(III)Mn(IV)(3) for S-2 to Mn(IV)(4) for S-3, implying an Mn-centered oxidation during each step of the photosynthetic oxygen evolution. The DFT simulations of the Mn Is absorption edge reproduce the experimentally measured curves quite well. By the half-height method, the theoretical IPEs are shifted by 0.93 eV for the S-0 -> S-1 transition, by 1.43 eV for the S-1 -> S-2 transition, and by 0.63 eV for the S-2 -> S-3 transition. The inflection point energy (IPE) shifts depend strongly on the method used to determine them, and the most interesting result is that the present clusters reproduce the shift in the S-2 -> S-3 transition obtained by both the half-height and second-derivative methods, thus giving strong support to the previously suggested structures and assignments.

  • 16671.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Zhuang, G. V.
    Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley.
    Augustsson, A.
    Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley.
    Liu, G.
    Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley.
    Nordgren, J.
    Department of Physics, Uppsala University.
    Guo, J. H.
    Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley.
    Ross, P. N.
    Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Conformation dependence of electronic structures of poly(ethylene oxide)2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 16, p. 7907-7914Article in journal (Refereed)
    Abstract [en]

    The electronic structure of pure poly(ethylene oxide) (PEO) for four different polymeric chain conformations has been studied by Hartree-Fock (HF) and density functional theory (DFT) through the analysis of their valence band photoelectron spectroscopy (VB-PES), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS). It is shown that the valence band of PEO presents specific conformation dependence, which can be used as a fingerprint of the polymeric structures. The calculated spectra have been compared with experimental results for PEO powder.

  • 16672. Brenan, K.E.
    et al.
    Engquist, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis, NA.
    Backward differentiation approximations of nonlinear differential/algebraic systems1988In: Mathematics of Computation, ISSN 0025-5718, E-ISSN 1088-6842, Vol. 51, no 84, p. 659-676Article in journal (Refereed)
    Abstract [en]

    Finite-difference approximations of dynamical systems modeled by nonlinear, semiexplicit, differential/algebraic equations are analyzed. Convergence for the backward differentiation method is proved for index two and index three problems when the numerical initial values obey certain constraints. The appropriate asymptotic convergence rates and the leading error terms are determined.

  • 16673.
    Brene, Sofia
    et al.
    KTH, School of Computer Science and Communication (CSC).
    Thome, Carl
    KTH, School of Computer Science and Communication (CSC).
    How Musical Instrumentation Affects Perceptual Identification of Musical Genres2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A listening experiment was conducted to investigate which musical instruments are the most important for defining certain musical genres. 66 participants genre classified a series of audio samples, with the same songs recurring both with full instrumentation and partial instrumentation. The report used the collected genre classifications to clarify therelationship between certain musical genres and song instrumentation. A numericalanalysis of the classifications, in the context of genre traditions and conventions, show that certain traditions hold true, while others do not. The most and least defining instrumentation for each genre was determined and discussed

  • 16674.
    Brengesjö, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Selin, Martine
    KTH, School of Information and Communication Technology (ICT).
    Tracking System: Suaineadh satellite experiment2011Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis is to present a tracking system for the Suaineadh satellite experiment. The experiment is a part of the REXUS (Rocket EXperiments for University Students) program and the objective is to deploy a foldable web in space. The assignment of this thesis is to develop a tracking system to find the parts from the Suaineadh experiment that will land on Earth. It is important to find the parts and recover all the data that the experiment performed during the travel in space. The implementation of this thesis investigates two different ways to track and find the experiment. The first way is to locate the experiment module by a Global Positioning System (GPS) and send the coordinates to a satellite modem, controlled by a programmed microprocessor.

    The other way is by using a radio beacon that sends a speciffic radio frequency. The results of this thesis presents a prototype for the tracking system with a GPS and the satellite modem and code example for the microprocessor. It also presents a working radio freqency beacon system on a Printed Circuit Board. The thesis had some unexpected incidents and had to change some directives. This rendered the work to take longer time then estimated. Despite the difficulties resulted this thesis in a working system to track the experiment.

  • 16675. Brennan, Donal J.
    et al.
    Brändstedt, Jenny
    Rexhepaj, Elton
    Foley, Michael
    Pontén, Fredrik
    Uhlén, Mathias
    KTH, School of Biotechnology (BIO), Proteomics.
    Gallagher, William M.
    O'Connor, Darran P.
    O'Herlihy, Colm
    Jirstrom, Karin
    Tumour-specific HMG-CoAR is an independent predictor of recurrence free survival in epithelial ovarian cancer2010In: BMC Cancer, ISSN 1471-2407, E-ISSN 1471-2407, Vol. 10, p. 125-Article in journal (Refereed)
    Abstract [en]

    Background: Our group previously reported that tumour-specific expression of the rate-limiting enzyme in the mevalonate pathway, 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR) is associated with more favourable tumour parameters and a good prognosis in breast cancer. In the present study, the prognostic value of HMG-CoAR expression was examined in tumours from a cohort of patients with primary epithelial ovarian cancer. Methods: HMG-CoAR expression was assessed using immunohistochemistry (IHC) on tissue microarrays (TMA) consisting of 76 ovarian cancer cases, analysed using automated algorithms to develop a quantitative scoring model. Kaplan Meier analysis and Cox proportional hazards modelling were used to estimate the risk of recurrence free survival (RFS). Results: Seventy-two tumours were suitable for analysis. Cytoplasmic HMG-CoAR expression was present in 65% (n = 46) of tumours. No relationship was seen between HMG-CoAR and age, histological subtype, grade, disease stage, estrogen receptor or Ki-67 status. Patients with tumours expressing HMG-CoAR had a significantly prolonged RFS (p = 0.012). Multivariate Cox regression analysis revealed that HMG-CoAR expression was an independent predictor of improved RFS (RR = 0.49, 95% CI (0.25-0.93); p = 0.03) when adjusted for established prognostic factors such as residual disease, tumour stage and grade. Conclusion: HMG-CoAR expression is an independent predictor of prolonged RFS in primary ovarian cancer. As HMG-CoAR inhibitors, also known as statins, have demonstrated anti-neoplastic effects in vitro, further studies are required to evaluate HMG-CoAR expression as a surrogate marker of response to statin treatment, especially in conjunction with current chemotherapeutic regimens.

  • 16676. Brennan, Donal J.
    et al.
    Laursen, Henriette
    O'Connor, Darran P.
    Borgquist, Signe
    Uhlén, Mathias
    KTH, School of Biotechnology (BIO), Proteomics.
    Gallagher, William M.
    Ponten, Fredrik
    Millikan, Robert C.
    Ryden, Lisa
    Jirström, Karin
    Tumor-specific HMG-CoA reductase expression in primary premenopausal breast cancer predicts response to tamoxifen2011In: Breast Cancer Research, ISSN 1465-5411, E-ISSN 1465-542X, Vol. 13, no 1, p. R12-Article in journal (Refereed)
    Abstract [en]

    Introduction: We previously reported an association between tumor-specific 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR) expression and a good prognosis in breast cancer. Here, the predictive value of HMG-CoAR expression in relation to tamoxifen response was examined. Methods: HMG-CoAR protein and RNA expression was analyzed in a cell line model of tamoxifen resistance using western blotting and PCR. HMG-CoAR mRNA expression was examined in 155 tamoxifen-treated breast tumors obtained from a previously published gene expression study (Cohort I). HMG-CoAR protein expression was examined in 422 stage II premenopausal breast cancer patients, who had previously participated in a randomized control trial comparing 2 years of tamoxifen with no systemic adjuvant treatment (Cohort II). Kaplan-Meier analysis and Cox proportional hazards modeling were used to estimate the risk of recurrence-free survival (RFS) and the effect of HMG-CoAR expression on tamoxifen response. Results: HMG-CoAR protein and RNA expression were decreased in tamoxifen-resistant MCF7-LCC9 cells compared with their tamoxifen-sensitive parental cell line. HMG-CoAR mRNA expression was decreased in tumors that recurred following tamoxifen treatment (P < 0.001) and was an independent predictor of RFS in Cohort I (hazard ratio = 0.63, P = 0.009). In Cohort II, adjuvant tamoxifen increased RFS in HMG-CoAR-positive tumors (P = 0.008). Multivariate Cox regression analysis demonstrated that HMG-CoAR was an independent predictor of improved RFS in Cohort II (hazard ratio = 0.67, P = 0.010), and subset analysis revealed that this was maintained in estrogen receptor (ER)-positive patients (hazard ratio = 0.65, P = 0.029). Multivariate interaction analysis demonstrated a difference in tamoxifen efficacy relative to HMG-CoAR expression (P = 0.05). Analysis of tamoxifen response revealed that patients with ER-positive/HMG-CoAR tumors had a significant response to tamoxifen (P = 0.010) as well as patients with ER-positive or HMG-CoAR-positive tumors (P = 0.035). Stratification according to ER and HMG-CoAR status demonstrated that ER-positive/HMG-CoAR-positive tumors had an improved RFS compared with ER-positive/HMG-CoAR-negative tumors in the treatment arm (P = 0.033); this effect was lost in the control arm (P = 0.138), however, suggesting that HMG-CoAR predicts tamoxifen response. Conclusions: HMG CoAR expression is a predictor of response to tamoxifen in both ER-positive and ER-negative disease. Premenopausal patients with tumors that express ER or HMG-CoAR respond to adjuvant tamoxifen.

  • 16677.
    Brennan, Robert
    et al.
    University of Calgary.
    Edström, KristinaKTH, School of Industrial Engineering and Management (ITM), Learning.Hugo, RonUniversity of Calgary.Roslöf, JanneTurku University of Applied Science.Songer, RobertKanazawa Technical College.Spooner, DanielÉcole Polytechnique, Montréal, Canada.
    Proceedings of the 13th International CDIO Conference2017Conference proceedings (editor) (Refereed)
  • 16678. Brenner, A.
    et al.
    Persson, K. M.
    Russell, L.
    Rosborg, Ingegerd
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Kozisek, F.
    Technical and mineral level effects of water treatment2015In: Drinking Water Minerals and Mineral Balance: Importance, Health Significance, Safety Precautions, Springer, 2015, p. 103-117Chapter in book (Other academic)
    Abstract [en]

    Reverse Osmosis is used for desalination of especially sea water in areas suffering from water shortage, and there are thousands and thousands of desalination plants around the world and more to come. The produced high–purity water tends to be corrosive, and lacks minerals, causing decreased daily intake and loss of minerals from the body. Thus, such water needs re–mineralization. Water with toxic substances is harmful, and is also often treated with RO. There are indexes to be used as guides to choose re–mineralization method after RO. However, mineral balance is not reached by remineralization, as only concentrations of calcium and bicarbonate, and in some cases magnesium is increased. Treatment with dissolution of dolomitic–calcitic limestone or other limestone with low levels of toxic elements is preferable. Hard water, on the other hand, may cause scaling, and is often softened, making the concentrations of calcium and magnesium low or extremely low. General advices on choice of treatment method to preserve or improve the mineral content and mineral balance of a water is presented in the chapter.

  • 16679. Brennhaugen, David D. E.
    et al.
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Computational Thermodynamics.
    Louzguine-Luzgin, Dmitri V.
    Arnberg, Lars
    Aune, Ragnhild E.
    Predictive modeling of glass forming ability in the Fe-Nb-B system using the CALPHAD approach2017In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 707, p. 120-125Article in journal (Refereed)
    Abstract [en]

    Accurate values needed for the most commonly used indicators of good Glass Forming Ability (GFA) in alloys, i.e. the liquidus (T-l), crystallization (T-x) and glass transition (T-g) temperatures, are only available after successful production of the metallic glass of interest. This has traditionally made discovery of new metallic glasses an expensive and tedious procedure, based on trial-and-error methodology. The present study aims at testing the CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) approach for predicting GFA in the Fe-Nb-B system by the use of the Thermo-Calc software and the thermodynamic database TCFE7. The melting temperatures and phase stabilities were calculated and combined with data for an atomic size mismatch factor, lambda, in order to identify and map potential high-GFA regions. Selected compositions in the identified regions were later produced by suction casting and melt spinning, and the potential success verified using X-Ray Diffraction (XRD). Differential Scanning Calorimetry (DSC) was also used to compare thermodynamic calculations for the model predictions, and evaluate standard GFA indicators. The model is found to fit well with literature data, as well as predict new bulk glassy compositions at and around Fe70.5Nb7B22.5. These results show promise in further predictive use of the model.

  • 16680.
    Brenning, Magnus
    et al.
    KTH, School of Technology and Health (STH).
    Olander, Björn
    KTH, School of Technology and Health (STH).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering.
    Vennberg, Johan
    KTH, School of Technology and Health (STH).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering. 2Laboratory for communication networks, School of Electrical Engineering, KTH.
    NeTraWeb - A Web-Based Traffic Flow Performance Meter2006In: 4th Swedish National Computer Networking Workshop SNCNW 2006, 2006Conference paper (Refereed)
    Abstract [en]

    This paper presents a web-based traffic flow performance meter. The NeTraWeb tool configures and automates the measurement activities, including storage and presentation of the main performance parameters.

  • 16681.
    Brenning, Nils
    KTH, Superseded Departments.
    A Necessary Condition for the Critical Ionization Velocity Interaction1982Report (Other academic)
  • 16682.
    Brenning, Nils
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    An Appendix to the Paper Te determination in low-density plasmas from the HeI 3889 Å and 5016 Å line intensities1981Report (Other academic)
  • 16683.
    Brenning, Nils
    KTH, Superseded Departments.
    An Improved Microwave Interferometer Technique for Plasma Density Measurements1983Report (Other academic)
  • 16684.
    Brenning, Nils
    KTH, Superseded Departments, Alfvén Laboratory.
    Current Limitation in Alfvén Wings1995Report (Other academic)
  • 16685.
    Brenning, Nils
    KTH, Superseded Departments.
    Electron Temperature Determination from the He I 3889Å and 5016Å Line Intensities1979Report (Other academic)
  • 16686.
    Brenning, Nils
    KTH, Superseded Departments.
    Electron Temperature Measurements in Low Density Plasmas by Helium Spectroscopy1977Report (Other academic)
  • 16687.
    Brenning, Nils
    KTH, Superseded Departments.
    Electron temperature measurements in low density plasmas by helium spectroscopy II - parameter limits for validity of different methods1978Report (Other academic)
  • 16688.
    Brenning, Nils
    KTH, Superseded Departments.
    Experiments on the Critical Ionization Velocity Interaction in Weak Magnetic Fields1980Report (Other academic)
  • 16689.
    Brenning, Nils
    KTH, Superseded Departments.
    "Horizontal" Thermal Equilibrium due to Excitation Transfer Between Excited States of Neutral He in Transient Plasma1978Report (Other academic)
  • 16690.
    Brenning, Nils
    KTH, Superseded Departments, Alfvén Laboratory.
    Interaction between a dust cloud and a magnetized plasma in relative motion2001In: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 29, no 2, p. 302-306Article in journal (Refereed)
    Abstract [en]

    The interaction between a dust cloud and a magnetized plasma is investigated by use of an idealized model where the dust particles have uniform size, a uniform density within the dust cloud, and start with the same velocity across the magnetic field in the plasma's rest frame. The interaction is found to be governed by a dimensionless parameter K which is a function of dust cloud, and ambient plasma, parameters. For K much smaller than unity, the interaction goes on for typically 1/(2 piK) gyro times, with the particles in the dust cloud performing gyro motions with decreasing radius, For K close to unity, the dust motion is stopped on the order of a dust particle gyro time, For the case K much greater than 1, the plasma in the flux tube through the dust cloud is dragged across the magnetic field over a distance of the order of Kr-d, where r(d) is the dust gyro radius, before the motion is stopped. Some expected effects for a more realistic dust cloud with density gradients, and containing dust with a spread in size, are discussed. The results have bearing on dusty plasma in space, e.g., models of the formation of spokes in Saturn's ring system.

  • 16691.
    Brenning, Nils
    KTH, Superseded Departments.
    On the Role of the Ionization Frequency to Gyrofrequency Ratio in the Critical Ionization Velocity Interaction1986Report (Other academic)
  • 16692.
    Brenning, Nils
    KTH, Superseded Departments.
    On the Role of the Magnetic Field Strength in Critical Ionization Velocity Interaction1985Report (Other academic)
  • 16693.
    Brenning, Nils
    KTH, Superseded Departments.
    On the Spoke Structure in Critical Velocity Rotating Plasmas1989Report (Other academic)
  • 16694.
    Brenning, Nils
    KTH, Superseded Departments.
    Review of Impact Experiments on the Critical Ionization Velocity1982Report (Other academic)
  • 16695.
    Brenning, Nils
    KTH, Superseded Departments.
    Testing a Very Good Microwave Interferometer1986Report (Other academic)
  • 16696.
    Brenning, Nils
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Axnas, I.
    Raadu, Michael A.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lundin, D.
    Helmerson, U.
    A bulk plasma model for dc and HiPIMS magnetrons2008In: Plasma sources science & technology (Print), ISSN 0963-0252, E-ISSN 1361-6595, Vol. 17, no 4Article in journal (Refereed)
    Abstract [en]

    A plasma discharge model has been developed for the bulk plasma (also called the extended presheath) in sputtering magnetrons. It can be used both for high power impulse magnetron sputtering (HiPIMS) and conventional dc sputtering magnetrons. Demonstration calculations are made for the parameters of the HiPIMS sputtering magnetron at Link "oping University, and also benchmarked against results in the literature on dc magnetrons. New insight is obtained regarding the structure and time development of the currents, the electric fields and the potential profiles. The transverse resistivity eta(perpendicular to) has been identified as having fundamental importance both for the potential profiles and for the motion of ionized target material through the bulk plasma. New findings are that in the HiPIMS mode, as a consequence of a high value of eta(perpendicular to), (1) there can be an electric field reversal that in our case extends 0.01-0.04m from the target, (2) the electric field in the bulk plasma is typically an order of magnitude weaker than in dc magnetrons, (3) in the region of electric field reversal the azimuthal current is diamagnetic in nature, i.e. mainly driven by the electron pressure gradient, and actually somewhat reduced by the electron Hall current which here has a reversed direction and (4) the azimuthal current above the racetrack can, through resistive friction, significantly influence the motion of the ionized fraction of the sputtered material and deflect it sideways, away from the target and towards the walls of the magnetron.

  • 16697.
    Brenning, Nils
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Axnas, I.
    Raadu, Michael A.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tennfors, E.
    Koepke, M.
    Radiation from an electron beam in a magnetized plasma: Whistler mode wave packets2006In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 111, no A11Article in journal (Refereed)
    Abstract [en]

    Experimental studies are reported of oscillations and radiation that is spontaneously excited by an electron beam which is shot along a diverging magnetic field into a plasma from a hot cathode. In the present study we focus on oscillations below the electron gyrofrequency, where we find that whistler mode radiation appears in the form of bursts, or wave packets, each with typically 0.1-1 mu s time duration, and which together cover typically a few percent of the full time. Wave packets are found in a broad frequency range of 7-40 MHz, while each individual wave packet is dominated by a single frequency. There is propagation along two routes: at the group velocity resonance cone angle, away from the central channel where the waves are excited, and in a channel along the magnetic field. Features of the whistler mode wave packets that are studied include (1) the statistics of amplitudes, frequencies, and time durations; (2) the propagation and decay of wave packets with different frequencies; (3) the group and phase velocities; and (4) how the wave packet production varies with the energy, and the current density, in the electron beam.

  • 16698.
    Brenning, Nils
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Axnäs, Ingvar
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Koepke, Mark
    KTH.
    Raadu, Michael A.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tennfors, Einar
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Radiation from an electron beam in magnetized plasma: excitation of a whistler mode wave packet by interacting, higher-frequency, electrostatic-wave eigenmodes2017In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 12, article id 124006Article in journal (Refereed)
    Abstract [en]

    Infrequent, bursty, electromagnetic, whistler-mode wave packets, excited spontaneously in the laboratory by an electron beam from a hot cathode, appear transiently, each with a time duration tau around similar to 1 mu s. The wave packets have a center frequency f(W) that is broadly distributed in the range 7 MHz < f(W) < 40 MHz. They are excited in a region with separate electrostatic (es) plasma oscillations at values of f(hf), 200 MHz < f(hf) < 500 MHz, that are hypothesized to match eigenmode frequencies of an axially localized hf es field in a well-defined region attached to the cathode. Features of these es-eigenmodes that are studied include: the mode competition at times of transitions from one dominating es-eigenmode to another, the amplitude and spectral distribution of simultaneously occurring es-eigenmodes that do not lead to a transition, and the correlation of these features with the excitation of whistler mode waves. It is concluded that transient coupling of es-eigenmode pairs at f(hf) such that vertical bar f(1, hf) - f(2, hf)vertical bar = f(W) < f(ge) can explain both the transient lifetime and the frequency spectra of the whistler-mode wave packets (f(W)) as observed in lab. The generalization of the results to bursty whistler-mode excitation in space from electron beams, created on the high potential side of double layers, is discussed.

  • 16699.
    Brenning, Nils
    et al.
    KTH, Superseded Departments.
    Bohm, Martin
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Dynamic Trapping of Electrons in Space Plasmas1989Report (Other academic)
  • 16700.
    Brenning, Nils
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Dynamic trapping and skidding of dense plasma clouds2004In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 70, no 03-feb, p. 153-156Article in journal (Refereed)
    Abstract [en]

    We investigate the possibility that the mechanism dynamic trapping can play a role in decoupling dense plasma clouds injected in a thinner ambient plasma, by establishing strong magnetic-field-aligned electric fields in the vicinity or in the edge of the cloud. Dynamic trapping has previously been shown to allow such fields to be established and maintained on the time scale of ion motion, also for arbitrarily low current densities. A model is presented of how such fields could arise and decouple injected plasma clouds, a mechanism which we call dynamic decoupling. A dimensionless parameter. the dynamic decoupling factor F-DD, is derived which gives an estimate of the importance of the process. One possible application is the CRRES ionospheric injection experiments where anomalous skidding has recently been reported. However. the dynamic decoupling mechanism might also play a role in naturally occurring situations, e.g. the impulsive penetration of plasmoids from the solar wind into the Earth's magnetosphere.

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