| 1. |
- Grinin, V. P., et al.
(författare)
-
Modelling UX Ori star eclipses based on spectral observations with the Nordic Optical Telescope - I. RR Tau
- 2023
-
Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 524:3, s. 4047-4061
-
Tidskriftsartikel (refereegranskat)abstract
- Based on observations obtained with the Nordic Optical Telescope (NOT) we investigate the spectral variability of the Herbig Ae star RR Tau. This star belongs to the UX Ori family, characterized by very deep fadings caused by the screening of the star with opaque fragments (clouds) of the protoplanetary discs. At the moments of such minima one observes strong spectral variability due to the fact that the dust cloud occults, for an observer, not only the star but also a part of the region where the emission spectrum originates. We calculated a series of obscuration models to interpret the observed variability of the H a line parameters. We consider two main obscuration scenarios: (1) the dust screen rises vertically above the circumstellar disc, and (2) the screen intersects the line-of-sight moving azimuthally with the disc. In both cases, the model of the emission region consists of a compact magnetosphere and a magnetocentrifugal disc wind. Comparison with observations shows that the first scenario explains well the variability of the radiation flux, the equivalent width, as well as the asymmetry of the H a line during eclipses, while the second scenario explains them only partly. This permits us to suggest that in the case of RR Tau, the main causes of the eclipses are either a structured disc wind, or the charged dust lifted along the field lines of the poloidal component of the magnetic field of the circumstellar disc.
|
|
| 2. |
- Kenny, Diarmuid T., et al.
(författare)
-
Mass spectrometric analysis of O-linked oligosaccharides from various recombinant expression systems
- 2013
-
Ingår i: Methods in Molecular Biology. - Totowa, NJ : Humana Press. - 1064-3745 .- 1940-6029. ; 988, s. 145-167, s. 145-167
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of O-linked glycosylation is one of the main challenges during structural validation of recombinant glycoproteins. With methods available for N-linked glycosylation in regard to oligosaccharide analysis as well as glycopeptide mapping, there are still challenges for O-linked glycan analysis. Here, we present mass spectrometric methodology for O-linked oligosaccharides released by reductive β-elimination. Using LC-MS and LC-MS2 with graphitized carbon columns, oligosaccharides are analyzed without derivatization. This approach provides a high-throughput method for screening during clonal selection, as well as product structure verification, without impairing sequencing ability. The protocols are exempli fied by analysis of glycoproteins from mammalian cell cultures (CHO cells) as well as insect cells and yeast. The data shows that the method can be successfully applied to both neutral and acidic O-linked oligosaccharides, where sialic acid, hexuronic acid, and sulfate are common substituents. Further characterization of O -glycans can be achieved using permethylation. Permethylation of O-linked oligosaccharides followed by direct infusion into the mass spectrometer provide information about oligosaccharide composition, and subsequent MS n experiments can be carried out to elucidate oligosaccharide structure including linkage information and sequence.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Karlsson, Lennart, et al.
(författare)
-
Modeling of residual stresses and distortion development
- 1997
-
Ingår i: Mathematical modelling of weld phenomena 3. - London : Institute of Materials. - 186125010X ; , s. 571-589
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Four examples are used to illustrate the current ability to calculate residual stress and distortion in situations of varying complexity. The methodology used is capable of allowing for interactions between thermal, mechanical, and transformation processes. Experimental values for a 2.25Cr-1Mo ferritic stainless steel were used in the simulation. It seems possible to simulate most welding situations given sufficient computer resources
|
|
| 6. |
|
|
| 7. |
- Oddy, A.S., et al.
(författare)
-
Microstructural predictions including arbitrary thermal histories, reaustenization and carbon segregation effects
- 1996
-
Ingår i: Canadian metallurgical quarterly. - 0008-4433 .- 1879-1395. ; 35:3, s. 275-283
-
Tidskriftsartikel (refereegranskat)abstract
- A microstructural prediction algorithm for hypoeutectoid steels is presented that accounts for carbon segregation effects and permits arbitrary thermal histories and austenite decomposition during reheating. Two austenization models are included: an instantaneous austenite formation and homogenization model; and a transient, heterogeneous austenite formation algorithm. The transient heterogeneous model predicts slightly slower formation rates than measured but compares favourably with experimental results. The two models provide upper and lower bounds for the austenization time. Predicted grain size, martensite fraction and hardness distributions are compared with measurements taken from a weld heat-affected zone (HAZ). Predictions are in good agreement with experimental results
|
|
| 8. |
- Powell, John, et al.
(författare)
-
The sensitivity of hybrid laser welding to variations in workpiece position
- 2011
-
Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3892. ; 12:1, s. 188-193
-
Tidskriftsartikel (refereegranskat)abstract
- High speed imaging has been used to analyze the sensitivity of the Hybrid laser welding process to variations in the laser-arcworkpiece geometry along the axis of the laser beam. The welding process was found to be stable within a certain range of workpiece positions. Outside of this range the process became unstable. If the workpiece was too close to the laser/arc combination, the two energy sources did not supplement each other sufficiently. If the workpiece was too far away the droplets from the arc interfered with the laser-keyhole interaction.
|
|
| 9. |
|
|
