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| 2. |
- Lundin, Per, 1971, et al.
(författare)
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A study of the surface integrity after machining by means of non-destructive testing methods
- 2013
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Ingår i: Proceedings of the International Conference on Advanced Manufacturing Engineering and Technologies Vol. 2. - Stockholm. - 9789175018935 ; , s. 283-292
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Konferensbidrag (refereegranskat)abstract
- During metal machining, depending on the cutting conditions, surface and subsurface microstructure alteration are occasionally observed. These alternations are normally referred as “white” and “dark” layers. Due to their different mechanical properties in comparison to the unaffected material, they will have an impact on the finished part. Controlling the quality of the machined parts regarding the surface microstructure alteration by means of non-destructive testing (NDT) methods would be beneficial from production point of view. In this study, the surface integrity of AISI 52100 steel machined at different cutting conditions resulting in white and dark layers with different characteristics were studied. Surface topography, microstructure and residual stresses were examined by using light scattering, optical microscopy and x-ray diffraction (XRD) techniques. Whilst surface characterization was emphasized, one NDT method – magnetic Barkhausen noise (BN) technique – is not well defined for this purpose. The correlation between all the applied techniques was therefore investigated and a preliminary model was developed for the influence of surface roughness, stress conditions and white and dark layer thicknesses on BN signal.
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| 3. |
- Ylva, Berglund, et al.
(författare)
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Framsynt efterord
- 2013
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Ingår i: Mellanrum. Fem års seminarier om social hållbarhet och stadsutveckling i Göteborg.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Hosseini, Seyed, et al.
(författare)
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Comparison of machining performance of stainless steel 316L produced by selective laser melting and electron beam melting
- 2022
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Ingår i: Procedia CIRP. - : Elsevier B.V.. - 2212-8271. ; , s. 72-77
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Konferensbidrag (refereegranskat)abstract
- Powder bed fusion processes based additively manufactured SS 316L components fall short of surface integrity requirements needed for optimal functional performance. Hence, machining is required to achieve dimensional accuracy and to enhance surface integrity characteristics. This research is focused on comparing the material removal performance of 316L produced by PBF-LB (laser) and PBF-EB (electron beam) in terms of tool wear and surface integrity. The results showed comparable surface topography and residual stress profiles. While the hardness profiles revealed work hardening at the surface where PBF-LB specimens being more susceptible to work hardening. The investigation also revealed differences in the progress of the tool wear when machining specimens produced with either PBF-LB or PBF-EB. .
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| 5. |
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| 6. |
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| 7. |
- Tehrani, Ali, 1976, et al.
(författare)
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Micelle growth of cationic gemini surfactants studied by NMR and by time-resoved fluorescence quenching
- 2013
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 1095-7103 .- 0021-9797. ; 405, s. 145-149
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Tidskriftsartikel (refereegranskat)abstract
- The micelle growth of a series of five cationic gemini surfactants has been investigated by time-resolved fluorescence quenching (TRFQ) and by two NMR techniques, line width analysis and diffusometry. The surfactant series was designed such that the effect of a number of variables could be assessed: length of the spacer unit, presence of ester bonds in the tails close to the head groups, and presence of a hydroxyl group in the spacer. For the gemini with long spacer, the micelles remained relatively small in size upon an increase of the concentration. The gemini surfactants with short spacer, on the other hand, showed a considerable micellar growth as the concentration was raised. It is of particular interest that the relatively simple line width analysis of one dimensional H-1 NMR spectra gave qualitatively the same results as the more sophisticated TRFQ and NMR diffusometry techniques.
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| 8. |
- Holmberg, Andreas, 1982-
(författare)
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Experimental Determination of Aeracoustic Sources in Low Mach Number Internal Flows
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, the in-duct experimental methods for determining aeroacoustic N-ports of in-duct elements are discussed and improved. The scattering matrix determination methods and the related wave decomposition methods are evaluated from measurements in an empty duct carrying a mean flow. The improvements of a new over-determination method for the source part of the N-port is studied using simulations and measurements; in quiescent air as well as measurements of the flow associated noise of a mixer plate, here a triangular plate inserted at an angle in a duct. The new method is shown to improve suppression of random errors while no improvement is achieved for bias errors. Further, the methods are applied in the study of two different aeroacoustic phenomena; one is the effect on the flow associated noise of the triangular plate achieved by varying the bending stiffness. For the most resilient plate tested, it is observed that when the Strouhal number of the flow noise coalesce with the Helmholtz number of a specific eigen-mode of the plate, the noise is drastically dampened. There is also a weaker broad band effect. The other phenomena studied is the amplification and attenuation obtained for sound waves propagating in a T-junction of rectangular ducts. It is found that by adding only 10% of inflow in the side branch relative to that in the main branch, the amplification is heavily increased. By adding another 10% the amplification is again similar to that of no side branch flow. Adding further flow lessens the effects still.
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| 9. |
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| 10. |
- Craig, Marina, 1978, et al.
(författare)
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Bacteria-triggered degradation of nanofilm shells for release of antimicrobial agents
- 2016
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Ingår i: Journal of materials chemistry. B. - : Royal Society of Chemistry (RSC). - 2050-750X .- 2050-7518. ; 4:4, s. 672-682
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Tidskriftsartikel (refereegranskat)abstract
- Due to an increase in lifestyle diseases in the developed world, the number of chronic wounds is increasing at a fast pace. Chronic wound infections are common and systemic antibiotics are usually used as a treatment. In this paper we describe an approach to encapsulate antimicrobial agents in hollow microcapsules covered with a nanofilm shell that degrades through the action of a virulence factor from Pseudomonas aeruginosa. The shell was assembled using the layer-by-layer (LbL) technique with poly-l-lysine and hyaluronic acid. The microcapsules were loaded with a model substrate or a drug. By crosslinking the components in the nanofilm, the film remained intact when exposed to human wound proteases. However, the film was degraded and the drug exposed when in contact with Pseudomonas aeruginosa's Lys-X specific protease IV. The antimicrobial efficacy of the drug-loaded microcapsules was confirmed by exposure to virulent Pseudomonas aeruginosa. The current study contributes to the establishment of a release platform for targeted treatment of topical infections with the aim of minimizing both overexposure to drugs and development of bacterial resistance.
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