| 1. |
- Aaboen, Lise, 1978, et al.
(författare)
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Capturing processes in longitudinal multiple case studies
- 2012
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Ingår i: Industrial Marketing Management. - : Elsevier BV. - 0019-8501. ; 41:2, s. 235-246
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses and suggests a methodological approach to capture processes in multiple case studies. While single case studies may address processes in an inductive or abductive manner, multiple case studies entail a stronger need for analytical frameworks and methodological tools developed ex ante in order to maintain focus on the same phenomena across cases and over time. This is, however, difficult to pursue in studies that focus on processes. The aim of the paper is to suggest an approach to longitudinal multiple case studies. We use an example of an on-going multiple case study aiming at capturing the processes of strategizing in terms of how the networking of start-up companies interplays with their ideas of future network positions. The paper concludes by suggesting the use of a combination of narratives and network drawings. Network drawings can be instrumental in capturing the past, the present and the future at different points in time for the individual cases. Based on these descriptions, change patterns and how these evolve can be analyzed and compared across cases and over time.
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| 2. |
- Aaboen, Lise, 1978, et al.
(författare)
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Strategizing as networking for a new venture
- 2012
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Ingår i: 22nd Nordic Workshop on Interorganisational Research, Trondheim, Norway, August 16-18.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Aal, A. A., et al.
(författare)
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Electrodeposition of selenium from 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate
- 2012
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 59, s. 228-236
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Tidskriftsartikel (refereegranskat)abstract
- Electrodeposition of Se films from air and water stable 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ionic liquid was studied in open air conditions. The electrochemical behavior of H2SeO3 on gold and copper substrates was investigated in ionic liquid-water mixtures, and the influence of the deposition parameters such as time and bath temperature on the crystallinity of the film was examined. For the gold substrate, a reddish deposit containing amorphous, hexagonal and rhombohedral Se phases was identified at room temperature, while a grayish film of hexagonal and rhombohedral phases was formed at higher temperatures. The reddish Se film was found to exhibit a smoother surface with lower reflectivity in comparison to the grayish one. The band gap of the reddish film was close to that of pure amorphous red Se reported in literature, while the band gap of the grayish film was close to the pure hexagonal film. Photoelectron spectroscopy and energy dispersive X-ray spectroscopy show that both films consist of pure Se with only slight surface contaminations by remnants from the electrodeposidon. In the case of a copper substrate, the electrodeposition of Se was accompanied by the formation of copper-selenide due to the reactivity of copper in H2SeO3.
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| 4. |
- Aal, A. A., et al.
(författare)
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Electrodeposition of selenium from 1-ethyl-3-methyl-imidazolium trifluromethylsulfonate
- 2012
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Ingår i: Journal of Solid State Electrochemistry. - : Springer Science and Business Media LLC. - 1433-0768 .- 1432-8488. ; 16:9, s. 3027-3036
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Tidskriftsartikel (refereegranskat)abstract
- The electrodeposition of thin selenium (Se) films from 1-ethyl-3-methyl-imidazolium trifluromethylsulfonate at room and elevated temperatures on gold and on copper substrates was studied under open-air conditions. The effect of bath temperature on the composition and structure of the deposited films was examined using cyclic voltammetry, chemical analysis and X-ray diffraction analysis. The obtained results showed that on gold substrate and at room temperature, a reddish Se film grows mainly in amorphous, monoclinic, rhombohedral and hexagonal structure, while at temperatures a parts per thousand yen90 A degrees C, a grayish film of hexagonal and rhombohedral structure is deposited. Photoelectron spectroscopy shows that both films consist of pure Se with only slight surface contaminations by remnants from the electrodeposition. Due to the differences in phase structure and the presence of the monoclinic phase, the reddish films showed higher light absorbance. The band gap of the reddish film is close to that of pure amorphous Se reported in literature. Deposition on copper substrate leads to formation of CuSe and CuSe2 at room temperature and at 70 A degrees C, respectively.
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| 5. |
- Aalto, Susanne, 1964, et al.
(författare)
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Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 537, s. 44-51
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Tidskriftsartikel (refereegranskat)abstract
- We obtained high-resolution (1.''55 × 1.''28) observations of HCN, HCO+, HNC 1-0 and HC3N 10-9 of the ultraluminous galaxy (ULIRG) Mrk 231 with the IRAM Plateau de Bure Interferometer.Results: We detect luminous emission from HCN, HCO+ and HNC 1-0 in the QSO ULIRG Mrk 231. All three lines show broad line wings - which are particularly prominent for HCN. Velocities are found to be similar ( ≈ ± 750 km s-1) to those found for CO 1-0. This is the first time bright HCN, HCO+ and HNC emission has been detected in a large-scale galactic outflow. We find that both the blue- and red-shifted line wings are spatially extended by at least 0.''75 (>700 pc) in a north-south direction. The line wings are brighter (relative to the line center intensity) in HCN than in CO 1-0 and line ratios suggest that the molecular outflow consists of dense (n > 104 cm-3) and clumpy gas with a high HCN abundance X(HCN) > 10-8. These properties are consistent with the molecular gas being compressed and fragmented by shocks in the outflow. Alternatively, HCN is instead pumped by mid-IR continuum, but we propose that this effect is not strong for the spatially extended outflowing gas. In addition, we find that the rotation of the main disk, in east-west direction, is also evident in the HCN, HCO+ and HNC line emission. An unexpectedly bright HC3N 10-9 line is detected inside the central 400 pc of Mrk 231. This HC3N emission may emerge from a shielded, dust-enshrouded region within the inner 40-50 pc where the gas is heated to high temperatures (200-300 K) by the AGN.
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| 6. |
- Aalto, Susanne, 1964
(författare)
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Molecules as tracers of galaxy evolution
- 2012
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Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 8:5287, s. 199-208
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Konferensbidrag (refereegranskat)abstract
- Studying the molecular phase of the interstellar medium in galaxies is fundamental for the understandingof the onset and evolution of star formation and the growth of supermassive black holes. Wecan use molecules as observational tools exploiting them as tracers of chemical, physical and dynamicalconditions. In this short review, key molecules (e.g. HCN, HCO+, HNC, HC3N, CN, H3O+) in identifyingthe nature of buried activity and its evolution are discussed including some standard astrochemical scenarios.Furthermore, we can use IR excited molecular emission to probe the very inner regions of luminousinfrared galaxies (LIRGs) allowing us to get past the optically thick dust barrier of the compact obscurednuclei, e.g. in the dusty LIRG NGC4418. High resolution studies are often necessary to separate effectsof excitation and radiative transport from those of chemistry - one example is absorption and effects ofstimulated emission in the ULIRG Arp220. Finally, molecular gas in large scale galactic outflows is brieflydiscussed.
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| 7. |
- Aalto, Susanne, 1964, et al.
(författare)
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Winds of change - a molecular outflow in NGC 1377? The anatomy of an extreme FIR-excess galaxy
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 546, s. Article Number: A68-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. Our goal was to investigate the molecular gas distribution and kinematics in the extreme far-infrared (FIR) excess galaxy NGC 1377 and to address the nature and evolutionary status of the buried source. Methods. We used high-(0.'' 65 x 0.'' 52, (65 x 52 pc)) and low-(4.'' 88 x 2.'' 93) resolution SubMillimeter Array (SMA) observations to image the (CO)-C-12 and (CO)-C-13 2-1 line emission. Results. We find bright, complex (CO)-C-12 2-1 line emission in the inner 400 pc of NGC 1377. The (CO)-C-12 2-1 line has wings that are tracing a kinematical component that appears to be perpendicular to the component traced by the line core. Together with an intriguing X-shape of the integrated intensity and dispersion maps, this suggests that the molecular emission of NGC 1377 consists of a disk-outflow system. Lower limits to the molecular mass and outflow rate are M-out(H-2) > 1 x 10(7) M-circle dot and (M) over dot > 8 M-circle dot yr(-1). The age of the proposed outflow is estimated to be 1.4 Myr, the extent to be 200 pc and the outflow speed to be V-out = 140 km s(-1). The total molecular mass in the SMA map is estimated to M-tot(H-2) = 1.5 x 10(8) M-circle dot (on a scale of 400 pc) while in the inner r = 29 pc the molecular mass is M-core(H-2) = 1.7 x 10(7) M-circle dot with a corresponding H-2 column density of N(H-2) = 3.4 x 10(23) cm(-2) and an average (CO)-C-12 2-1 brightness temperature of 19 K. (CO)-C-13 2-1 emission is found at a factor 10 fainter than (CO)-C-12 in the low-resolution map while (CO)-O-18 2-1 remains undetected. We find weak 1 mm continuum emission of 2.4 mJy with spatial extent less than 400 pc. Conclusions. Observing the molecular properties of the FIR-excess galaxy NGC 1377 allows us to probe the early stages of nuclear activity and the onset of feedback in active galaxies. The age of the outflow supports the notion that the current nuclear activity is young - a few Myr. The outflow may be powered by radiation pressure from a compact, dust enshrouded nucleus, but other driving mechanisms are possible. The buried source may be an active galactic nucleus (AGN) or an extremely young (1 Myr) compact star-burst. Limitations on size and mass lead us to favor the AGN scenario, but additional studies are required to settle this question. In either case, the wind with its implied mass outflow rate will quench the nuclear power source within the very short time of 5-25 Myr. It is possible, however, that the gas is unable to escape the galaxy and may eventually fall back onto NGC 1377 again.
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| 8. |
- Aas, W., et al.
(författare)
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Lessons learnt from the first EMEP intensive measurement periods
- 2012
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 12:17, s. 8073-8094
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Tidskriftsartikel (refereegranskat)abstract
- The first EMEP intensive measurement periods were held in June 2006 and January 2007. The measurements aimed to characterize the aerosol chemical compositions, including the gas/aerosol partitioning of inorganic compounds. The measurement program during these periods included daily or hourly measurements of the secondary inorganic components, with additional measurements of elemental- and organic carbon (EC and OC) and mineral dust in PM1, PM2.5 and PM10. These measurements have provided extended knowledge regarding the composition of particulate matter and the temporal and spatial variability of PM, as well as an extended database for the assessment of chemical transport models. This paper summarise the first experiences of making use of measurements from the first EMEP intensive measurement periods along with EMEP model results from the updated model version to characterise aerosol composition. We investigated how the PM chemical composition varies between the summer and the winter month and geographically. The observation and model data are in general agreement regarding the main features of PM10 and PM2.5 composition and the relative contribution of different components, though the EMEP model tends to give slightly lower estimates of PM10 and PM2.5 compared to measurements. The intensive measurement data has identified areas where improvements are needed. Hourly concurrent measurements of gaseous and particulate components for the first time facilitated testing of modelled diurnal variability of the gas/aerosol partitioning of nitrogen species. In general, the modelled diurnal cycles of nitrate and ammonium aerosols are in fair agreement with the measurements, but the diurnal variability of ammonia is not well captured. The largest differences between model and observations of aerosol mass are seen in Italy during winter, which to a large extent may be explained by an underestimation of residential wood burning sources. It should be noted that both primary and secondary OC has been included in the calculations for the first time, showing promising results. Mineral dust is important, especially in southern Europe, and the model seems to capture the dust episodes well. The lack of measurements of mineral dust hampers the possibility for model evaluation for this highly uncertain PM component. There are also lessons learnt regarding improved measurements for future intensive periods. There is a need for increased comparability between the measurements at different sites. For the nitrogen compounds it is clear that more measurements using artefact free methods based on continuous measurement methods and/or denuders are needed. For EC/OC, a reference methodology (both in field and laboratory) was lacking during these periods giving problems with comparability, though measurement protocols have recently been established and these should be followed by the Parties to the EMEP Protocol. For measurements with no defined protocols, it might be a good solution to use centralised laboratories to ensure comparability across the network. To cope with the introduction of these new measurements, new reporting guidelines have been developed to ensure that all proper information about the methodologies and data quality is given.
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| 9. |
- Abadikhah, Hossein, 1987, et al.
(författare)
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Higher order beam equations
- 2012
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Ingår i: Civil-Comp Proceedings. - Stirlingshire, UK : Civil-Comp Press. - 1759-3433. ; 99
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers the dynamic equations of circular cylindrical beams. The method is based on the three dimensional theory, adopting the generalized Hamilton's principle. By adopting a power series expansion method in the radial coordinate, together with a Fourier series expansion in the circumferential direction, this procedure results in sets of equations of motion together with consistent sets of end boundary conditions. These are derived in a systematic fashion up to arbitrary order, and are believed to be asymptotically correct. As such, the equations of motion are hyperbolic. Among the derived equation set are recursion relations, from which it is possible to express higher order displacement and stress fields in terms of lower order displacement fields. Results are obtained for all Fourier modes, among which axisymmetric, torsional and flexural modes are special cases. Special attention is paid towards the flexural mode. Using different truncation orders of the present theory, comparisons may be performed with classical theories such as the Euler-Bernoulli and the Timoshenko theories, besides the exact theory. Numerical examples are presented for dispersion curves of an infinite beam for the three lowest modes. Here various truncation orders are presented, as well as the exact theory. It is clear that higher accuracy is obtained as more terms are used. The lowest mode curve is accurately captured in the lower frequency range for all theories. Higher order truncations are indistinguishable from the exact curves in the presented range. Concerning eigenfrequencies, the three lowest frequencies for two different beams are presented for different truncation orders, classical theories as well as the exact theory for simply supported ends. As for the dispersion curves, the series expansion results converge to the exact results as the power series orders are increased. It is clear that more accurate results are obtained for lower frequencies and slender beams as expected. The Timoshenko theory is astonishingly accurate while the Euler-Bernoulli theory confirms the well known fact that this theory renders reasonably accurate results for slender beams in the low frequency spectra. Various plots on mode shapes and stress distributions are compared for the fundamental frequency for a simply supported beam. Here the curves using the lowest series expansion theory are very close to the exact results. There are more pronounced differences between theories for the mode shapes and the stress distributions, compared to the eigenfrequency calculations and the dispersion curves. The differences are most prominent for the stress distributions.
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| 10. |
- Abay, Simon, 1980, et al.
(författare)
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High Critical-Current Superconductor-InAs Nanowire-Superconductor Junctions
- 2012
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 12:11, s. 5622-5625
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Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication of InAs nanowires coupled to superconducting leads with high critical current and widely tunable conductance. We implemented a double lift off nanofabrication Method to get very short nanowire devices with Ohmic contacts. We observe very high critical. currents of up to 800 nA in a wire with a diameter of 80 nm. The current- voltage characteristics of longer and suspended nanowires display,either. Coulomb blockade or supercurrent depending on a local gate voltage, combining different regimes of transport in a single device.
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