| 1. |
|
|
| 2. |
|
|
| 3. |
- Horne, Merle, et al.
(författare)
-
Swedish as a [+Continuity] language : left-edge prosody and right-edge morphosyntax
- 2012
-
Ingår i: Discourse and grammar : a festschrift in honor of Valéria Molnár. - 9789163704116 ; , s. 333-341
-
Bokkapitel (refereegranskat)abstract
- Abstract in UndeterminedSwedish and French avoid placing focused constituents at the left periphery of sentences. This has previously been suggested to be due to phonological factors. Here, we develop this idea and argue that the reason for avoiding focus at the left edge in these languages is the existence of syntactically related prosodic prominences in the beginning of utterances. Initial focal accents would overlap with the syntactically related accents, forcing a suboptimal prosodic structure. Further, we provide evidence for such a left-edge boundary tone in Swedish main clauses, as well as for a complementary strong tendency in Swedish to associate the right edge of sentences with focus.
|
|
| 4. |
- Klingvall Ek, Rebecca, 1985-
(författare)
-
Electron beam melting: Impact of part surface properties on metal fatigue and bone ingrowth
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- AbstractThe aim of this thesis is to investigate aspects on how additive manufacturing (AM) contributes to functional bone implants with the use of the electron beam melting (EBM) technology. AM manufactures parts according to computer-aided design, and the EBM technology melts powder using an electron beam, which acts similar to a laser beam. The topics discussed in this thesis are related to surface roughness that originate from the melted metal powder, and the thesis tries to define some aspects that affect implant functionality. Process parameters steering the electron beam and biocompatibility arising from the surface texture were the initial parts of the PhD studies, and the other half focused on post-processing and fatigue, which are important for medical and industrial applications. There are six studies in this compilation thesis. They are abbreviated as P - process parameters, M - medical applications, and F - fatigue. Studies P, M2, F2, and F3 are journal articles, and M1 and F1 are conference proceedings.Study P used design of experiments to investigate how process parameters affect the surface roughness of as-built EBM-manufactured parts and concluded that beam speed and energy (current) were the most important parameters that influence the surface roughness.In studies M1 and M2, EBM-manufactured specimens of cobalt-chromium and titanium alloys were used to evaluate biocompatibility. The blood chamber method quantified the reactions of the human whole blood in contact with the metal surfaces, and the results showed how the as-built EBM surface roughness contributed to coagulation and bone healing.Rotating beam fatigue equipment was used in studies F1–F3 and study F1 discussed the size effect on fatigue loaded as-built specimens and included specimens with different sizes and with or without hot isostatic pressing (HIP). Study F2 compared as-built and machined specimens and study F3 investigated how Hirtisation, which is a patented electrochemical surface treatment, and HIP affect the fatigue properties that originate from the electrochemical polishing surface topography. The studies showed that a decreased surface roughness increased the fatigue resistance while the stress concentrations (Kt) in the surface of EBM-manufactured specimens decreased.The thesis concludes that EBM-manufactured as-built surfaces are suitable for direct contact with the bone, and that HIP does not improve the fatigue resistance of parts with as-built surfaces, where crack initiation starts at notches.
|
|
| 5. |
|
|
| 6. |
- Klingvall Ek, Rebecca, 1985-, et al.
(författare)
-
Fatigue properties of Ti-6Al-4V manufactured using electron beam melting
- 2017
-
Ingår i: Proceedings Euro PM 2017: International Powder Metallurgy Congress and Exhibition 2017. - Brussels : EPMA European Powder Metallurgy Association. - 9781899072491
-
Konferensbidrag (refereegranskat)abstract
- The interest in powder bed fusion additive manufacturing methods, such as electron beam melting (EBM), is increasing constantly and main business areas driving the development are aerospace and implant manufacturers. EBM manufactured parts have a rather coarse surface roughness mainly originating from the layer thickness and the powder grains melted by the electron beam. Thus, there is an interest in understanding how the surface properties influences the fatigue performance of the material. In this study, EBM manufactured Ti-6Al-4V was investigated at high cycle fatigue using rotating beam and different types of specimens regarding geometry, as-built and hot isostatic pressing (HIP) post-processing were evaluated. The results confirm that as-built surfaces affect the fatigue limit and a small size specimen geometry for rotating beam fatigue testing is proposed as a part of material and process verification.
|
|
| 7. |
|
|
| 8. |
- Klingvall Ek, Rebecca, 1985-, et al.
(författare)
-
Micro- to Macroroughness of Additively Manufactured Titanium Implants in Terms of Coagulation and Contact Activation
- 2017
-
Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence Publishing. - 0882-2786 .- 1942-4434. ; 32:3, s. 565-574
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study aimed to evaluate how as-built electron beam melting (EBM) surface properties affect the onset of blood coagulation. The properties of EBM-manufactured implant surfaces for placement have, until now, remained largely unexplored in literature. Implants with conventional designs and custom-made implants have been manufactured using EBM technology and later placed into the human body. Many of the conventional implants used today, such as dental implants, display modified surfaces to optimize bone ingrowth, whereas custom-made implants, by and large, have machined surfaces. However, titanium in itself demonstrates good material properties for the purpose of bone ingrowth. Materials and Methods: Specimens manufactured using EBM were selected according to their surface roughness and process parameters. EBM-produced specimens, conventional machined titanium surfaces, as well as PVC surfaces for control were evaluated using the slide chamber model. Results: A significant increase in activation was found, in all factors evaluated, between the machined samples and EBM-manufactured samples. The results show that EBM-manufactured implants with as-built surfaces augment the thrombogenic properties. Conclusion: EBM that uses Ti6Al4V powder appears to be a good manufacturing solution for load-bearing implants with bone anchorage. The as-built surfaces can be used "as is" for direct bone contact, although any surface treatment available for conventional implants can be performed on EBM-manufactured implants with a conventional design.
|
|
| 9. |
- Klingvall Ek, Rebecca, 1985-
(författare)
-
SURFACE PROPERTIES OF IMPLANTS MANUFACTURED USING ELECTRON BEAM MELTING
- 2016
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis summarizes the results concerning the manufacture of medical implants for bone replacement using electron beam melting (EBM) which is an additive manufacturing (AM) technology, and aims to satisfy the engineering needs for the medical functionality of manufacturing technology. This thesis has focused on some microscopic properties for surfaces and bone integration. The process parameters of EBM manufacturing were studied to ascertain whether they have impacts on surface appearance, as surface properties have impacts on bone integration and implant performance.EBM manufacturing uses an electron beam to melt metal powder onto each layer in a manner akin to welding. The electron beam is controlled by process parameters that may be altered to a certain extent by the operator. There are individual process parameters for every material, and new parameters are set when developing new materials. In this thesis, process parameters in default settings were altered to ascertain whether it was possible to specify process parameters for implant manufacturing. The blood chamber model was used for thromboinflammation validation, using human whole blood. The model is used to identify early reactions of coagulation and immunoreactions. The material used in this study was Ti6Al4V-ELI, which is corrosion resistant and has the same surface oxide layers as titanium, and CoCr-F75, which has high stiffness, is wear-resistant and is commonly used in articulating joints.The study shows that among the process parameters researched, a combination of speed and current have the most impact on surface roughness and an interaction of parameters were found using design of experiment (DOE). As-built EBM surfaces show thrombogenicity, which in previous studies has been associated with bone ingrowth.Surface structure of as-build EBM manufactured surfaces are similar to implants surfaces described by Pilliar (2005), but with superior material properties than those of implants with sintered metals beads. By altering the process parameters controlling the electron beam, surface roughness of as-build parts may be affected, and the rougher EBM manufactured surfaces tend to be more thrombogen than the finer EBM manufactured surfaces. As-build EBM manufactured surfaces in general show more thrombogenicity than conventional machined implants surfaces.
|
|
| 10. |
- Klingvall, Mikael, 1971-
(författare)
-
Adaptability or Efficiency : Towards a theory of institutional development in organizations
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organizations, once established, tend not to change, typically going obsolete as society continues to evolve. This makes adaptability an important issue. Organizational members must make sense to each other, or coordination suffers. They must also make sense to environmental actors, or the organization will not achieve the support it needs to survive. This sense-making is a process of institutionalization, of constructing a shared understanding of the organization's enterprise, business and environment. When environmental actors adopt new priorities, ideas and modes of thinking, organizations must develop a new understanding of reality or go obsolete. To stay adaptable, organizations needs to contain competing perspectives. But the pressures to conform and to coordinate make it difficult for established organizations to adapt, trapped by the very benefits of increased efficiency. Using an agent-based model of organizational institutionalization, I show that an organization's adaptability is highly dependent on structural elements that affect the member interaction frequencies, and that organizations that leverage the strength of weak ties between member groups can maintain adaptability. The effects of changes to any of these elements are decidedly non-linear, however, which helps explain why it is difficult to design effective organizations. Organizational structure is one part of a tri-partite framework of institutional development in organizations and of organizational adaptability, where the other two parts are the individual characteristics of the members and the content of the organizational culture.
|
|
