788 research outputs found
Positive Beurteilung der schweizerischen Lehrerfortbildung (und Lehrergrundausbildung) im Computer-/Informatikbereich im internationalen Vergleich
Die Lehrerinnen und Lehrer der Schweiz beurteilen die Einführung als gut, die sie für die Benutzung der Computer im Unterricht erhalten haben. Das geht aus der Stellungnahme von 5\u27000 Personen hervor, die im 7. bis 13. Schuljahr unterrichten. Die Daten sind wesentlich positiver als in anderen Ländern. Das Ergebnis ist eine erfreuliche Bestätigung für die Lehrerfortbildung, die Projektgruppen zur Informatikeinführung und für die Lehrergrundausbildung. Zudem signalisiert es auch eine gute Basis für weitere Innovationen. Merkwürdigerweise meinen die vorgesetzten Rektoren und Informatikzuständigen, die Lehrer dürften noch mehr wissen und können. Wir legen die entsprechenden Daten vor und formulieren einige Vermutungen zu diesem paradoxen Phänomen
On the development of a harmonic balance method for aeroelastic analysis
To efficiently simulate time-periodic, non-linear flows in turbomachinery
a Harmonic Balance (HB) method has recently been developed within the framework of DLR’s compressible, Unsteady Reynolds Averaged Navier- tokes (URANS) solver TRACE. As a hybrid time- and frequency-domain method, that solves directly for the complex valued solution harmonics of the URANS equations, the approach allows both the integration of highly accurate non-reflecting boundary conditions and the efficient resolution of non-linear flow phenomena. In the current work the HB-solver is extended and applied to investigate the aeroelastic problem of flutter in turbomachinery. Within this context the HB-method is developed, under consideration of the Geometric Conservation Law (GCL), to support deforming meshes. To validate the approach the well documented aeroelastic test case Standard Configuration 10 is simulated and results are compared to those obtained with an inhouse time-linearized solver and reference datafrom the literature
Multiple supermassive black hole systems: SKA's future leading role
Galaxies and supermassive black holes (SMBHs) are believed to evolve through
a process of hierarchical merging and accretion. Through this paradigm,
multiple SMBH systems are expected to be relatively common in the Universe.
However, to date there are poor observational constraints on multiple SMBHs
systems with separations comparable to a SMBH gravitational sphere of influence
(<< 1 kpc). In this chapter, we discuss how deep continuum observations with
the SKA will make leading contributions towards understanding how multiple
black hole systems impact galaxy evolution. In addition, these observations
will provide constraints on and an understanding of stochastic gravitational
wave background detections in the pulsar timing array sensitivity band (nanoHz
-microHz). We also discuss how targets for pointed gravitational wave
experiments (that cannot be resolved by VLBI) could potentially be found using
the large-scale radio-jet morphology, which can be modulated by the presence of
a close-pair binary SMBH system. The combination of direct imaging at high
angular resolution; low-surface brightness radio-jet tracers; and pulsar timing
arrays will allow the SKA to trace black hole binary evolution from separations
of a galaxy virial radius down to the sub-parsec level. This large dynamic
range in binary SMBH separation will ensure that the SKA plays a leading role
in this observational frontier.Comment: 11 pages, 4 figures. To be published in the proceedings of "Advancing
Astrophysics with the Square Kilometre Array", PoS(AASKA14)151, in pres
Single-crystal neutron diffraction study of metamict zircon up to 2000 K
High-temperature single-crystal measurements of metamict zircon were performed up to 2000 K and the recrystallization was monitored using the width and intensity of selected peaks. Full data sets were collected at room temperature, 1573 and 1823 K. The changes in the probability density function (p.d.f.) of the O atoms revealed important features of the recrystallization. The measurements were done in air using a mirror furnace and performed on the D19 four-circle diffractometer at the ILL equipped with a vertically curved two-dimensional position-sensitive detector
Early enteral feeding in conservatively managed stage II necrotizing enterocolitis is associated with a reduced risk of catheter-related sepsis
Aims: To compare the effect of fasting period duration on complication rates in neonates managed conservatively for necrotizing enterocolitis (NEC) Bell stage II. Methods: We conducted a multicenter study to analyze retrospectively multiple data collected by standardized questionnaire on all admissions for NEC between January 2000 and December 2006. NEC was staged using modified Bell criteria. We divided the conservatively managed neonates with NEC Bell stage II into two groups (those fasted for 5days) and compared the complication rates. Results: Of the 47 conservatively managed neonates Bell stage II, 30 (64%) fasted for 5days (range 6-16days). There were no significant differences for any of the patient characteristics analyzed. One (3%) and four (24%) neonates, respectively, developed post-NEC bowel stricture. One (3%) and two neonates (12%) suffered NEC relapse. None and five (29%) neonates developed catheter-related sepsis. Conclusion: Shorter fasting after NEC appears to lower morbidity after the acute phase of the disease. In particular, shorter-fasted neonates have significantly less catheter-related sepsis. We found no benefit in longer fastin
The effect of particle size on the intrinsic dissolution of acetylsalicylic acid
Dissolution has an important role in the release of active ingredients from pharmaceutical preparations. The main focus of dissolution testing is in the area of quality control and product development, since the test yields information related to the composition and manufacturing variables. Moreover, the rate of dissolution is studied during the course of a new chemical entity development since it predicts potential bioavailability. The research objective of this study was to examine the dissolution rate of acetylsalicylic acid nondisintegrating compacts made up from four different particle sizes while exposing only a fixed surface area to the dissolution medium. This is also known as the rate of intrinsic dissolution, which is regarded as a characterization study and is therefore not referenced in individual monographs.peer-reviewe
Material Extrusion of Structural Polymer–Aluminum Joints—Examining Shear Strength, Wetting, Polymer Melt Rheology and Aging
Generating polymer–metal structures by means of additive manufacturing offers huge
potential for customized, sustainable and lightweight solutions. However, challenges exist, primarily
with regard to reliability and reproducibility of the additively generated joints. In this study, the
polymers ABS, PETG and PLA, which are common in material extrusion, were joined to grit-blasted
aluminum substrates. Temperature dependence of polymer melt rheology, wetting and tensile single lap-shear strength were examined in order to obtain appropriate thermal processing conditions. Joints
with high adhesive strength in the fresh state were aged for up to 100 days in two different moderate
environments. For the given conditions, PETG was most suitable for generating structural joints.
Contrary to PETG, ABS–aluminum joints in the fresh state as well as PLA–aluminum joints in the
aged state did not meet the demands of a structural joint. For the considered polymers and processing
conditions, this study implies that the suitability of a polymer and a thermal processing condition
to form a polymer–aluminum joint by material extrusion can be evaluated based on the polymer’s
rheological properties. Moreover, wetting experiments improved estimation of the resulting tensile
single-lap-shear strength
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