489 research outputs found
Synthesis of New Iminocoumarins Bearing Parabanic Moieties
The synthesis of novel substituted 3-p-nitro-phenyliminocoumarins and corresponding N-ureaiminocoumarins is described. The condensation of these materials with oxalyl chloride leads to the corresponding N-parabanic iminocoumarins, which have not previously been described, in moderate or good yields and high selectivity. The structures were characterized by Fourier transform infrared, 1H and 13C NMR, and elemental analysis
Set-based design of mechanical systems with design robustness integrated
This paper presents a method for parameter design of mechanical products based on a set-based approach. Set-based concurrent engineering emphasises on designing in a multi-stakeholder environment with concurrent involvement of the stakeholders in the design process. It also encourages flexibility in design through communication in terms of ranges instead of fixed point values and subsequent alternative solutions resulting from intersection of these ranges. These alternative solutions can then be refined and selected according to the designersâ preferences and clientsâ needs. This paper presents a model and tools for integrated flexible design that take into account the manufacturing variations as well as the design objectives for finding inherently robust solutions using QCSP transformation through interval analysis. In order to demonstrate the approach, an example of design of rigid flange coupling with a variable number of bolts and a choice of bolts from ISO M standard has been resolved and demonstrated
Evaluation of process causes and influences of residual stress on gear distortion
In the automotive industry, heat treatment of components is implicitly related to distortion. This phenomenon is particularly obvious in the case of gears because of their typical and precise geometry. Even if distortion can be anticipated to an extent by experience, it remains complex to comprehend. This paper presents an approach to estimate the distortion based on the idea of a distortion potential taking into account not only geometry but also the manufacturing process history. Then the idea is developed through simulation and experiments including annealing to understand the impact of residual stress on gear distortion in an industrial case study
Hypogenic Caves in Provence (France).
Älanek obravnava razvoj jam Adaouste in Champignons v francoski Provansi. Nove raziskave kaĆŸejo, da jami ni oblikovala meteorna voda, paÄ pa voda, ki je v arteĆĄkih pogojih dotekala iz globin. V Älanku so obravnavane specifiÄne jamske skalne oblike in sedimenti, ki podpirajo trditev o hipogenem razvoju jam.Two dry caves from French Provence (Adaouste and Champignons caves) were until now considered as »normal« caves having evolved under meteoric water flow conditions. A new approach gives evidence of a hypogenic origin from deep water uprising under artesian conditions. Specific morphologies and sediments associated with this hydrology are discussed
Ultrafast Magneto-Acoustics in Nickel Films
We report about the existence of magneto-acoustic pulses propagating in a
200-nm-thick ferromagnetic nickel film excited with 120 fs laser pulses. They
result from the coupling between the magnetization of the ferromagnetic film
and the longitudinal acoustic waves associated to the propagation of the
lattice deformation induced by the femtosecond laser pulses. The
magneto-acoustic pulses are detected from both the front and back sides of the
film, using the time-resolved magneto-optical Kerr technique, measuring both
the time dependent rotation and ellipticity. We show that the propagating
acoustic pulse couples efficiently to the magnetization and is strong enough to
induce a precession of the magnetization. It is due to a transient change of
the crystalline anisotropy associated to the lattice deformation. It is shown
that the results can be interpreted by combining the concepts of acoustic pulse
propagation and ultrafast magnetization dynamics.Comment: 4 pages, 3 figures, Submitted to Physical Review Letters on November
30th 201
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