433 research outputs found
Metal Laminated Tooling - A Quick and Flexible Tooling Concept
For the fast manufacturing of complex formed tools Fraunhofer IWS works together with partners from the industry on a constant automation solution for cutting, packaging and adding steel sheet cutouts. With the selection of the most suitable connecting technology, also requirements must be considered to quality, surface quality and the production costs. Deep drawing or stamping tools do not require a complete connection of the single metal sheets. Here, a fast and economical connection is the main objective. Due to simple automation, laser beam welding offers itself as joining process. On the other hand, a temperature-steady connection of the sheet metal lamellas is necessary for injection molds, which can resist the injection pressures.Mechanical Engineerin
Mass Loss Evolution and the Formation of Detached Shells around TP-AGB Stars
The origin of the so called 'detached shells' around AGB stars is not fully
understood, but two common hypotheses state that these shells form either
through the interaction of distinct wind phases or an eruptive mass loss
associated with a He-shell flash. We present a model of the formation of
detached shells around thermal pulse asymptotic giant branch (TP-AGB) stars,
based on detailed modelling of mass loss and stellar evolution, leading to a
combination of eruptive mass loss and wind interaction.
The purpose of this paper is first of all to connect stellar evolution with
wind and mass loss evolution and demonstrate its consistency with observations,
but also to show how thin detached shells around TP-AGB stars can be formed.
Previous attempts to link mass loss evolution with the formation of detached
shells were based on approximate prescriptions for the mass loss and have not
included detailed modelling of the wind formation as we do here. (abridged)Comment: 16 pages, 15 figures. Accepted for publication in Astronomy &
Astrophysic
Observing and modeling the dynamic atmosphere of the low mass-loss C-star R Sculptoris at high angular resolution
We study the circumstellar environment of the carbon-rich star R Scl using
the near- and mid-infrared high spatial resolution observations from the
ESO-VLTI instruments VINCI and MIDI. These observations aim at increasing our
knowledge of the dynamic processes in play within the very close circumstellar
environment where the mass loss of AGB stars is initiated. Data are interpreted
using a self-consistent dynamic model. Interferometric observations do not show
any significant variability effect at the 16 m baseline between phases 0.17 and
0.23 in the K band, and for both the 15 m baseline between phases 0.66 and 0.97
and the 31 m baseline between phases 0.90 and 0.97 in the N band. We find
fairly good agreement between the dynamic model and the spectrophotometric data
from 0.4 to 25 m. The model agrees well with the time-dependent flux data
at 8.5 m, whereas it is too faint at 11.3 and 12.5 m. The VINCI
visibilities are reproduced well, meaning that the extension of the model is
suitable in the K-band. In the mid-infrared, the model has the proper extension
to reveal molecular structures of C2H2 and HCN located above the stellar
photosphere. However, the windless model used is not able to reproduce the more
extended and dense dusty environment. Among the different explanations for the
discrepancy between the model and the measurements, the strong nonequilibrium
process of dust formation is one of the most probable. The complete dynamic
coupling of gas and dust and the approximation of grain opacities with the
small-particle limit in the dynamic calculation could also contribute to the
difference between the model and the data
Transforming power: social science and the politics of energy choices
This paper addresses key implications in momentous current global energy choices â both for social science and for society. Energy can be over-used as a lens for viewing social processes. But it is nonetheless of profound importance. Understanding possible âsustainable energyâ transformations requires attention to many tricky issues in social theory: around agency and structure and the interplay of power, contingency and practice. These factors are as much shaping of the knowledges and normativities supposedly driving transformation, as they are shaped by them. So, ideas and hopes about possible pathways for change â as well as notions of âthe transitionâ itself â can be deeply constituted by incumbent interests. The paper addresses these dynamics by considering contending forms of transformation centring on renewable energy, nuclear power and climate geoengineering. Several challenges are identified for social science. These apply especially where there are aims to help enable more democratic exercise of social agency. They enjoin responsibilities to âopen upâ (rather than âclose downâ), active political spaces for critical contention over alternative pathways. If due attention is to be given to marginalised interests, then a reflexive view must be taken of transformation. The paper ends with a series of concrete political lessons
26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15â20 July 2017
This work was produced as part of the activities of FAPESP Research,\ud
Disseminations and Innovation Center for Neuromathematics (grant\ud
2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud
FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud
supported by a CNPq fellowship (grant 306251/2014-0)
Recent Developments in Laminated Tooling by Multiple Laser Processing
This research and development project is founded by the German Federal Ministry of
Education and Research (BMBF) within the framework concept "research for the production
of tomorrow" and cared by the agency âProduction and Production Technologiesâ (PFT) at
the Forschungszentrum Karlsruhe.Mechanical Engineerin
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