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Wyszukujesz frazę "Hansen, K." wg kryterium: Autor


Wyświetlanie 1-9 z 9
Tytuł:
Healed or non-healed? Computed tomography (CT) visualisation of morphology of bite trace ichnotaxa on a dinosaur bone
Autorzy:
Jacobsen, A. R.
Lauridsen, H.
Fiirgaard, B.
Boel, L. W. T.
Hansen, K.
Powiązania:
https://bibliotekanauki.pl/articles/191178.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Bite traces
dinosaur bone
theropod
CT
computed tomography
stereomicroscopy
Opis:
Bite traces on fossilised bones can provide important information on predator-prey relations and interactions in ancient environments. In 2009, two new ichnotaxa, Linichnus serratus and Knethichnus parallelum, were introduced to develop the application of bite traces as an ichnological tool. Ichnotaxa defined by theropod bite traces can provide useful information for understanding feeding behaviour. However, objective interpretation of possible bite traces can be difficult using traditional visual inspection. In this study, the bite traces on a fossilised dinosaur bone were comprehensively examined by correlating traditional naked-eye in spection with computed tomography (CT) imaging, used to visualise the internal morphology of the bite traces and in particular, to clarify the appearance of one possibly healed bite trace. A forensic pathologist visually examined the bone with the aid of stereomicroscopy and a radiologist analysed the CT scans. Sixteen different scanner settings were used to optimise the CT parameters and avoid signal at tenuation, in the form of hypointense artefacts in the central trabeculated part of the bone fragment. The use of CT scanning provided information on internal morphology from the vicinity of the bite trace, including hyperdense zones, not identified using visual inspection alone. By applying the extended CT scale, the dense and radiopaque cortical bone layer could be clearly identified and applied as a pathomorphological marker to correctly distinguish non-healed from healed wounds. In conclusion, the authors demonstrate that external visual examination of trace fossils by ichnologists in combination with interior examination using CT imaging can be applied to characterise ichnotaxa defined by bite traces and potentially provide clues on ancient feeding behaviour.
Źródło:
Annales Societatis Geologorum Poloniae; 2015, 85, 3; 457-464
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steady and unsteady analysis of NACA 0018 airfoil in vertical-axis wind turbine
Autorzy:
Rogowski, K.
Hansen, M. O. L.
Maroński, R.
Powiązania:
https://bibliotekanauki.pl/articles/279244.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
airfoil characteristics
vertical-axis wind turbine
computational fluid dynamics
Opis:
Numerical results are presented for aerodynamic unsteady and steady airfoil characteristics of the NACA 0018 airfoil of a two-dimensional vertical-axis wind turbine. A geometrical model of the Darrieus-type wind turbine and the rotor operating parameters used for numerical simulation are taken from the literature. Airfoil characteristics are investigated using the same mesh distribution around the airfoil edges and two turbulence models: the RNG k-ε and the SST Transition. Computed results for the SST Transition model are in good agreement with the experiment, especially for static airfoil characteristics.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 1; 203-212
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DLTS Study of Be-Doped p-Type AlGaAs/GaAs MBE Layers
Autorzy:
Szatkowski, J.
Płaczek-Popko, E.
Sierański, K.
Hansen, O.
Powiązania:
https://bibliotekanauki.pl/articles/1992215.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
71.55.Eq
Opis:
Deep-level transient spectroscopy method was applied to study deep hole traps in p-type Al$\text{}_{0.5}$Ga$\text{}_{0.5}$As grown on GaAs semi-insulating substrate by MBE. Five hole traps labelled by us as H0 to H4 were found. For the traps H1, H3 and H4 thermal activation energies obtained from Arrhenius plots were equal to: E$\text{}_{H1}$=0.15 eV, E$\text{}_{H3}$=0.4 eV, and E$\text{}_{H4}$=0.46 eV. Hole emission from the trap H2 was electric field dependent with the thermal activation energy extrapolated to zero-field equal to 0.37 eV. Capture cross-sections for the traps H1 and H4 were thermally activated with energetic barriers 0.04 eV (for H1) and 0.18 eV (for H4).
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 565-569
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved 2.5 GHz Electron Pump: Single-Electron Transport through Shallow-Etched Point Contacts Driven by Surface Acoustic Waves
Autorzy:
Utko, P.
Gloos, K.
Hansen, J. B.
Lindelof, P. E.
Powiązania:
https://bibliotekanauki.pl/articles/2035753.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
72.50.+b
06.20.Jr
Opis:
We present an experimental study of a 2.5 GHz electron pump based on the quantized acoustoelectric current driven by surface acoustic waves through a shallow-etched point contact in a GaAs/AlGaAs heterostructure. At low temperatures and with an additional counter-propagating surface acoustic waves beam, up to n=20 current plateaus at I=nef could be resolved, where n is an integer, e the electron charge, and f the surface acoustic waves frequency. In the best case the accuracy of the first plateau at 0.40 nA was estimated to beΔ I/I=±25 ppm over 0.25 mV in gate voltage, which is better than previous results.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 533-538
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Different Quantization Mechanisms in Single-Electron Pumps Driven by Surface Acoustic Waves
Autorzy:
Utko, P.
Gloos, K.
Bindslev Hansen, J.
Sørensen, C.
Lindelof, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047039.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
72.50.+b
73.21.La
Opis:
We have studied the acoustoelectric current in single-electron pumps driven by surface acoustic waves. We have found that in certain parameter ranges two different sets of quantized steps dominate the acoustoelectric current versus gate-voltage characteristics. In some cases, both types of quantized steps appear simultaneously though at different current values, as if they were superposed on each other. This could indicate two independent quantization mechanisms for the acoustoelectric current.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 403-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lattice Sitting of Platinum Atoms in Diluted SiGe Alloys
Autorzy:
Dobaczewski, L.
Bonde Nielsen, K.
Nylandsted Larsen, A.
Lundsgaard Hansen, J.
Gościński, K.
Peaker, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/1969056.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Ln
71.55.Cn
73.40.Lq
Opis:
In this report we present high-resolution spectra obtained with a use of the Laplace transform deep level transient spectroscopy for platinum diffused into dilute (0-5% of Ge) SiGe alloys. Very significant changes are observed in the spectra associated with the transition metals as the germanium content is altered. We interpret these spectra in terms of the configurations of silicon and germanium atoms surrounding the transition metal. In order to explain the observed behaviour both the first and second nearest neighbour shells are considered.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 297-299
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantitative assessment of risk to ship traffic in the fehmarnbelt fixed link project
Autorzy:
Rasmussen, F. M.
Glibbery, K. A. K.
Melchild, K.
Hansen, M. G.
Jensen, T. K.
Lehn-Schiøler, T.
Randrup-Thomsen, S.
Powiązania:
https://bibliotekanauki.pl/articles/2069413.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
quantitative risk assessment
QRA
ship collision
ShipRisk
facility safety assessment
FSA
IMO guideline
AIS data
Opis:
Rambøll is on behalf of Femern A/S carrying out navigational studies of the vessel traffic conditions in the Fehmarnbelt in connection with the establishment of a future Fehmarnbelt fixed link, a 19 km long bridge or immersed tunnel connection crossing the Fehmarnbelt. The focus is on documenting safety and efficiency for the vessel traffic when a fixed link is crossing the Fehmarnbelt. Rambøll has developed the ShipRisk software package to perform the quantitative risk assessments in the Fehmarnbelt fixed link project. Focus in this article is on describing the background for estimating frequencies of ship accidents in ShipRisk and describe factors influencing the accident scenarios and present the work performed for testing and verifying the model.
Źródło:
Journal of Polish Safety and Reliability Association; 2012, 3, 1; 123--134
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rock glaciers in the Jutulsessen, Dronning Maud Land, East Antarctica
Autorzy:
Rudolph, Elizabeth M.
Meiklejohn, K. Ian
Hansen, Christel D.
Hedding, David W.
Nel, Werner
Powiązania:
https://bibliotekanauki.pl/articles/2042133.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
East Antarctica
Jutulsessen
rock glacier
permafrost
climate change
Źródło:
Polish Polar Research; 2018, 39, 1; 1-17
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of air quality on sleep and cognitive performance in school children aged 10–12 years: a double-blinded, placebo-controlled, crossover trial
Autorzy:
Klausen, Frida B.
Amidi, Ali
Kjærgaard, Søren K.
Schlünssen, Vivi
Ravn, Peter
Østergaard, Kirsten
Gutzke, Vibeke H.
Glasius, Marianne
Grønborg, Therese K.
Hansen, Stefan N.
Zachariae, Robert
Wargocki, Pawel
Sigsgaard, Torben
Powiązania:
https://bibliotekanauki.pl/articles/2203016.pdf
Data publikacji:
2023-05-23
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
sleep quality
cognition
indoor air
CO2 exposure
school children
RCT study
Opis:
Objectives To investigate the effect of CO₂ during sleep on next-morning cognitive performance in young schoolchildren, the authors performed a double-blind fully balanced crossover placebo-controlled study. Material and Methods The authors included 36 children aged 10–12 years in the climate chamber. The children slept at 21°C in 6 groups each at 3 different conditions separated by 7 days in a random order. Conditions were as follows: high ventilation with CO₂ at 700 ppm, high ventilation with added pure CO₂ at 2000–3000 ppm, and reduced ventilation with CO₂ at 2–3000 ppm and bioeffluents. Children were subjected to a digital cognitive test battery (CANTAB) in the evening prior to sleep and on the next morning after breakfast. Sleep quality was monitored with wrist actigraphs. Results There were no significant exposure effects on cognitive performance. Sleep efficiency was significantly lower at high ventilation with CO₂ at 700 ppm which is considered to be a chance effect. No other effects were seen, and no relation between air quality during sleep and next-morning cognitive performance was observed in the children emitting an estimated 10 l CO₂ /h per child. Conclusions No effect of CO₂ during sleep was found on next day cognition. The children were awakened in the morning, and spent from 45–70 min in well-ventilated rooms before they were tested. Hence, it cannot be precluded that the children have benefitted from the good indoor air quality conditions before and during the testing period. The slightly better sleep efficiency during high CO₂ concentrations might be a chance finding. Hence, replication is needed in actual bedrooms controlling for other external factors before any generalizations can be made.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2023, 36, 2; 177-191
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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