| 1. |
- Belgardt, Christian, et al.
(författare)
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Self-Assembly of Ordered Colloidal Nanoparticle Films in Few-Micron Wide Laser-Desorbed Lines of Octadecylsiloxane Monolayers on Silicon Oxide Surfaces
- 2014
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Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlag. - 1438-1656 .- 1527-2648. ; 16:9, s. 1090-1097
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Tidskriftsartikel (refereegranskat)abstract
- We report about a maskless technique to deposit colloidal polystyrene particles in patterned stripes with a line width as narrow as 1.5m. Our approach is based on the digital patterning of a hydrophobic octadecylsiloxane self-assembled monolayer (SAM) on a silicon oxide surface by laser-assisted decomposition and desorption of its organic parts. For hydrophilic stripes of the micropatterned SAM area down to widths of approximately 1.5m, we observed ordered, mainly monolayered stripes of colloidal polystyrene nanoparticles using a modified vertical deposition technique, dipping the silicon substrate into a colloidal suspension at an angle of around 45 degrees with respect to the surface normal of the liquid. The mechanism of this so-called slope self-assembly [Wu et al., Langmuir2013, 29, 14017] and its limitations with respect to stacking can be explained in the framework of a meniscus moving along the steps of alternating surface energy with the decreasing width of the hydrophilic stripes during the deposition process [Fustin et al., Langmuir2004, 20, 9114].
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| 2. |
- Berts, Ida, et al.
(författare)
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Polymeric Smart Coating Strategy for Titanium Implants
- 2014
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 16:11, s. 1340-1350
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan based hydrogel coatings can mimic extracellular matrix components and incorporate growth factors that can be released during a progressive degradation while new tissue regenerates. This paper describes a structural characterization of a hydrogel coating made of modified hyaluronan polymers and how these coatings interact with bone morphogenetic protein-2 (BMP-2). Quartz crystal microbalance and neutron reflectivity measurements were used for in-situ, real-time measurements of the adsorption properties of polymers and proteins on smooth titanium oxide surfaces that mimic implant products in orthopedics. The adsorption of BMP-2 on a bare titanium oxide surface is compared to that on titanium oxide coated with different chemically modified hyaluronan, the most important being hyaluronan with bisphosphonate groups (HA-BP). The subsequent release of the BMP-2 from these hydrogel coatings could be triggered by calcium ions. The amount of adsorbed protein on the surfaces as well as the amount of released protein both depend on the type of hyaluronan coating. We conclude that HA-BP coated titanium oxide surfaces provide an excellent material for growth factor delivery in-vivo.
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| 3. |
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| 4. |
- Dadbakhsh, Sasan, et al.
(författare)
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In situ formation of particle reinforced Al matrix composite by selective laser melting of Al/Fe 2O 3 powder mixture
- 2012
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 14:1-2, s. 45-48
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a novel in situ reaction approach to produce Al matrix composites from a powder mixture of Al/5a wt% Fe 2O 3 by using selective laser melting (SLM). It is found that the SLM process not only is able to produce three-dimensional parts, but also is capable of activating an in situ reaction in the powder mixture, producing particles mainly from alumina (Al 2O 3) and iron combinations (such as Fe 2+Al 2O 4) in Al matrix. These particles (as reinforcements) can be distributed uniformly with a good particle/matrix interface under controlled conditions.
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| 5. |
- Mapelli, Valeria, 1978, et al.
(författare)
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Viability Study of the Use of Cast Iron Open Cell Foam as Microbial Fuel Cell Electrodes
- 2013
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 15:3, s. 112-117
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, the development of new green technologies has been promoted worldwide both by public andprivate institutions. In this context the research on microbial fuel cells (MFC) represents a promisingalternative to carbon based energy sources. Unfortunately, this technology has been always affected by too lowcurrent density output for allowing an intensive application in the industrial and civil field. The study dealswith this limitation and focuses on the implementation of metallic sponges, specifically cast iron based, aselectrodes, aiming at increasing the exposed surface and thus the current density at the MFC anode. Cast ironwas selected because of its low toxicity for the microorganisms, however its high melting point carries severalproblems for the manufacture process. Parallel to this, the realization of electrodes using foamed metals impliesfurther issues related to the generation of correct pore size distribution and adequate bacterial activity. Forinstance, the metal foams are expected to be open-cell type, so that there can be an efficientmass transport alsoto the inner regions of the electrode. In order to control these parameters the metal sponges are produced byinfiltration of cast iron on ceramic beds. Combining previous data with themeasurements of power generationefficiency the authors conclude the study attempting to design MFCs with metal foamed electrodes.
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| 6. |
- Pranzas, P. Klaus, et al.
(författare)
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Characterization of Hydrogen Storage Materials and Systems with Photons and Neutrons
- 2011
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 13:8, s. 730-736
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Tidskriftsartikel (refereegranskat)abstract
- Complex hydrides are very promising candidates for future light-weight solid state hydrogen storage materials. The present work illustrates detailed characterization of such novel hydride materials on different size scales by the use of synchrotron radiation and neutrons. The comprehensive analysis of such data leads to a deep understanding of the ongoing processes and mechanisms. The reaction pathways during hydrogen desorption and absorption are identified by in situ X-ray diffraction (XRD). Function and size of additive phases are estimated using X-ray absorption spectroscopy (XAS) and anomalous small-angle X-ray scattering (ASAXS). The structure of the metal hydride matrix is characterized using (ultra) small-angle neutron scattering (SANS/USANS). The hydrogen distribution in tanks filled with metal hydride material is studied with neutron computerized tomography (NCT). The results obtained by the different analysis methods are summarized in a final structural model. The complementary information obtained by these different methods is essential for the understanding of the various sorption processes in light metal hydrides and hydrogen storage tanks.
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| 7. |
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| 8. |
- Strondl, A., et al.
(författare)
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Effect of Processing on Microstructure and Physical Properties of Three Nickel-Based Superalloys with Different Hardening Mechanisms
- 2012
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 14:7, s. 427-438
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Tidskriftsartikel (refereegranskat)abstract
- The nickel-based superalloys Inconel alloy 600, Udimet alloy 720, and Inconel alloy 718 were produced by electron beam melting (EBM), casting, and directional solidification (DS). The distance between dendrites and the size of the precipitates indicated the difference in solidification rates between the three processes. In this study, the solidification rate was fastest with EBM, closely followed by casting, whereas it was much slower with DS. In the directional solidified materials the direction was the fastest and thus, preferred growth direction. The EBM samples show a sharp (001)[100] texture in the building direction and in the two scanning directions of the electron beam. Macrosegregation was observed in some cast and directionally solidified samples, but not in the EBM samples. The melting temperatures are in good agreement with literature and the narrow melting interval of IN600 compare to UD720 and IN718 might reduce the risk of incipient melting during EBM processing. Porosity was observed in the EBM samples and the reasons are discussed. However, EBM seems to be a feasible process route to produce nickel-based superalloys with well-defined texture, no macrosegregation and a rapidly solidified microstructure.
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