| 1. |
|
|
| 2. |
- Andersson, K., et al.
(författare)
-
Failure Investigation of an Airline Engine Failure During Take Off
- 2013
-
Ingår i: Praktische Metallographie/Practical Metallography. - : Walter de Gruyter GmbH. - 0032-678X. ; 50:12, s. 821-830
-
Tidskriftsartikel (refereegranskat)abstract
- An Iran Airlines CF6-8002A2F engine had a turbine failure during takeoff from the Arlanda airport in Sweden, in January 2010. Failure investigation of the engine was performed by Lufthansa Technik AG (LHT). The Swedish Accident Investigation Board (SHK) requested a second opinion of the available High Pressure Turbine (HPT) Diffuser Aft Seal hardware, received from LHT, and because of GKN Aerospace Sweden's extensive experience as Original Equipment Manufacturer (OEM) of Swedish fighter engines this second failure analysis work was performed by GKN. The failure investigation of the Diffuser Aft Seal pieces and fragments received from LHT revealed no fractures or fatigue cracks which are believed to be evidences of the primary cause to the failure. However, a secondary fatigue crack was found in an aft tooth fragment from the Diffuser Aft Seal. This tooth fragment has also a machining step on the forward surface, between a repair weld and the original tooth, with a geometry which gives a stress concentration factor of about 2.5 for radial and bending stresses in this area. This machining step may have contributed to initiate a fatigue crack in the seal tooth.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Klement, W. J. Niels, et al.
(författare)
-
Selective Analysis of Redox Processes at the Electrode Interface with Time-Resolved Raman Spectroscopy
- 2023
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 39:30, s. 10383-10394
-
Tidskriftsartikel (refereegranskat)abstract
- Electrochemistry and electrochemical reactions are increasinglyimportant in the transition to a sustainable chemical industry. Theelectron transfer that drives such reactions takes place within nanometersof the electrode surface, and follow-up chemical reactions take placewithin the diffusion layer. Hence, understanding electrochemical reactionsrequires time-, potential-, and spatially resolved analysis. The confocalnature of Raman spectroscopy provides high spatial resolution, inaddition to detailed information on molecular structure. The intrinsicweakness of nonresonant Raman scattering, however, is not sensitiveenough for relatively minor changes to the solution resulting fromreactions at the electrode interface. Indeed, the limit of detectionis typically well above the concentrations used in electrochemicalstudies. Here, we show that surface-enhanced Raman scattering (SERS)and resonance Raman (rR) spectroscopy allow for spatially and time-resolvedanalysis of solution composition at (<1-2 nm) and near (within5 & mu;m) the electrode surface, respectively, in a selective mannerfor species present at low (<1 mM) concentrations. We show changesin concentration of species at the electrode surface, without theneed for labels, specific adsorption, or resonance enhancement, usinga SERS-active gold electrode prepared readily by electrochemical surfaceroughening. A combination of smooth and roughened gold electrodesis used to distinguish between surface and resonance enhancement usingthe well-known redox couples ferrocene and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid) (ABTS). We discuss the impact of specific adsorption on thespectral analysis with the ruthenium(II) polypyridyl complex, [Ru(bpy)(3)](2+). The dual function of the electrode (surfaceenhancement and electron transfer) in the analysis of solution processesis demonstrated with the reversible oxidation of TMA (4,N,N-trimethylaniline), where transient soluble species are identifiedin real time, with rapid spectral acquisition, making use of localizedenhancement. We anticipate that this approach will find use in elucidatingelectro(catalytic) reactions at electrode interfaces.
|
|
| 10. |
|
|
