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| 2. |
- Brueckner, Frank, et al.
(author)
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Fabrication of metallic multi-material components using Laser Metal Deposition
- 2017
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In: Solid Freeform Fabrication 2017. - : The University of Texas at Austin. ; , s. 2530-2538
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Conference paper (other academic/artistic)abstract
- Meanwhile, Laser Metal Deposition (LMD) is a well-known Additive Manufacturing technology used in various industrial branches as energy, tooling or aerospace. It can be used for the fabrication of new components but also repair applications. So far, volume build-ups were mostly carried out with one single material only. However, loading conditions may strongly vary and, hence, the use of more than one material in a component would yield major benefits. By means of multi-material build-ups, cost-intensive alloys could be used in highly-loaded areas of the part, whereas the remaining part could be fabricated with cheaper compositions. The selection of combined materials strongly depends on the requested thermo-physical and mechanical properties. Within this contribution, possibilities of material combinations by LMD and selected examples of beneficial multi-material use are presented.
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| 3. |
- Ekeberg, Tomas, 1983-, et al.
(author)
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Three-dimensional structure determination with an X-ray laser
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Other publication (other academic/artistic)abstract
- Three-dimensional structure determination of a non-crystalline virus has been achieved from a set of randomly oriented continuous diffraction patterns captured with an X-ray laser. Intense, ultra-short X-ray pulses intercepted a beam of single mimivirus particles, producing single particle X-ray diffraction patterns that are assembled into a three-dimensional amplitude distribution based on statistical consistency. Phases are directly retrieved from the assembled Fourier distribution to synthesize a three-dimensional image. The resulting electron density reveals a pseudo-icosahedral asymmetric virion structure with a compartmentalized interior, within which the DNA genome occupies only about a fifth of the volume enclosed by the capsid. Additional electron microscopy data indicate the genome has a chromatin-like fiber structure that has not previously been observed in a virus.
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| 5. |
- Hendl, Julius, et al.
(author)
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NDE for Additive Manufacturing
- 2022. - 1
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In: Handbook of Nondestructive Evaluation 4.0. - Cham : Springer. - 9783030732066 - 9783030732059 ; , s. 665-696
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Book chapter (other academic/artistic)abstract
- By means of additive manufacturing (AM) complex-shaped parts can be manufactured using a broad range of different materials. The latter can be supplied in the form of powder, wire, paste material, or even as foil. Various technologies are covered by the term “Additive Manufacturing,” for example, direct energy deposition (DED), laser powder bed fusion (LPBF), fused filament fabrication (FFF), or binder jetting printing (BJP). In all varieties, parts are manufactured layer by layer which results in changed material properties compared to conventional manufacturing routes, for example, mechanical properties or fatigue life. To reach a conformal material deposition without defects such as lack of fusion, delamination or cracking, an optimal process window with well-chosen parameters (e.g., beam power, spot size, scanning speed) has to be identified.For nondestructive evaluation (NDE), different approaches can be used to classify AM manufactured parts regarding their defect structure and consequentially their performance:1.Process optimization and understanding of defect formation in order to prevent defects 2.In situ measurements by a variety of integrated sensors and (IR) cameras for direct process observations 3.Post-processing NDE methods such as ultrasonic testing, X-ray, or computer tomography (CT)If the three approaches are simultaneously executed, a prediction of the effect of defects can be made for certain cases.
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| 6. |
- Hämmerle, Christoph H F, et al.
(author)
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Biology of soft tissue wound healing and regeneration : consensus report of group 1 of the 10th European workshop on periodontology
- 2014
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In: Journal of Clinical Periodontology. - : John Wiley & Sons. - 0303-6979 .- 1600-051X. ; 41:s15, s. S1-S5
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Journal article (other academic/artistic)abstract
- BACKGROUND:The scope of this consensus was to review the biological processes of soft tissue wound healing in the oral cavity and to histologically evaluate soft tissue healing in clinical and pre-clinical models. AIMS:To review the current knowledge regarding the biological processes of soft tissue wound healing at teeth, implants and on the edentulous ridge. Furthermore, to review soft tissue wound healing at these sites, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. COLLECTION OF DATA:Searches of the literature with respect to recessions at teeth and soft tissue deficiencies at implants, augmentation of the area of keratinized tissue and soft tissue volume were conducted. The available evidence was collected, categorized and summarized. FUNDAMENTAL PRINCIPLES OF ORAL SOFT TISSUE WOUND HEALING:Oral mucosal and skin wound healing follow a similar pattern of the four phases of haemostasis, inflammation, proliferation and maturation/matrix remodelling. The soft connective tissue determines the characteristics of the overlaying oral epithelium. Within 7-14 days, epithelial healing of surgical wounds at teeth is completed. Soft tissue healing following surgery at implants requires 6-8 weeks for maturation. The resulting tissue resembles scar tissue. Well-designed pre-clinical studies providing histological data have been reported describing soft tissue wound healing, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. Few controlled clinical studies with low numbers of patients are available for some of the treatments reviewed at teeth. Whereas, histological new attachment has been demonstrated in pre-clinical studies resulting from some of the treatments reviewed, human histological data commonly report a lack of new attachment but rather long junctional epithelial attachment and connective tissue adhesion. Regarding soft tissue healing at implants human data are very scarce. CONCLUSIONS:Oral soft tissue healing at teeth, implants and the edentulous ridge follows the same phases as skin wound healing. Histological studies in humans have not reported new attachment formation at teeth for the indications studied. Human histological data of soft tissue wound healing at implants are limited. CLINICAL RECOMMENDATIONS:The use of barriers membranes, growth and differentiation factors and soft tissue substitutes for the treatment of localized gingival/mucosal recessions, insufficient amount of keratinized tissue and insufficient soft tissue volume is at a developing stage.
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| 7. |
- Müller, Eike Christoph
(author)
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Axionlike particles, quantum loops, and supernovae : The role of quantum loop corrections for astrophysical ALPs
- 2022
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Licentiate thesis (other academic/artistic)abstract
- In this thesis the quantum field theory and astrophysical phenomenology of axionlike particles (ALPs) are studied. The effective field theory of ALPs is reviewed with a special focus on quantum loops, the renormalization group equations, and the equivalent forms of the interaction between ALPs and fermions.To study the phenomenology of ALPs, both as dark matter candidate in the first paper that this thesis is based on, and as they are produced in supernova explosions in the second paper, an effective coupling between ALPs and photons is defined. In this way, the full one-loop effect of ALP-electron interactions can straightforwardly be incorporated in phenomenological analyses.It is pointed out that the effective coupling is different in decay and ALP-photon conversion processes. Importantly, the resulting loop-induced ALP-photon conversion rate does not vanish for ALPs much lighter than the electron, as was often stated in the literature.With this field theoretical basis, it is pointed out in the first paper that the decay of ALPs into photons via quantum loops has severe consequences for direct detection searches of ALP dark matter. In a large part of the parameter space that these experiments are sensitive to, the ALP would either not be long-lived enough to be dark matter, or the x-rays or gamma-rays originating from the decays of the ALP relic density should have been observed by indirect detection searches. Hence, while more heavy and strongly interacting ALPs coupled to electrons cannot be dark matter, many relatively lighter and weaker interacting models are ruled out already by indirect detection constraints.Furthermore, ALPs can be produced efficiently in supernovae even if they interact only very weakly. The absence of anomalous cooling in SN1987A constrains the ALP-photon and ALP-electron interactions. Similarly, since no gamma-rays arrived on earth directly after the observation of the neutrino burst of SN1987A, further constraints can be derived.Using the effective loop-induced coupling, some of the strongest bounds on the coupling between electrons and ALPs in the keV and MeV mass range are calculated in the second paper. Additionally, some technical details of the calculation are discussed and improved.
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| 8. |
- Ravensburg, Eike Christoph, 1995-
(author)
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Astrophysical probes of axionlike particles
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis is a contribution to the search for new fundamental physics in the form of axionlike particles (ALPs). ALPs are relatively light and feebly interacting particles that are part of many theories extending the Standard Model of particle physics, e.g., to solve the strong-CP problem, the dark matter problem, or quantum gravity in the form of string theory. We use astrophysical observations mainly related to core-collapse supernovae to search for signatures of the existence of ALPs.In the first part of this thesis, we study in some detail the effective field theory of ALPs with a focus on quantum loop effects. These loops necessarily induce correlations between the effective couplings of the theory such that, e.g., the interaction between ALPs and photons sourced by quantum loops due to their coupling to leptons cannot be neglected. In the second part of the thesis, as well as in three of the publications that it is comprised of, we demonstrate the importance of the effective ALP-photon coupling defined here for dark matter ALPs, whose loop induced decay to photons excludes a large region of their parameter space that was believed to be accessible to direct detection experiments, as well as ALPs produced in supernova explosions. Through the loop-induced interaction with photons more ALPs can be produced in supernovae than was calculated previously. Additionally, the photon-decay channel implies ways in which ALPs could have been observed that would not be possible if they only interacted with leptons. For instance, if a nearby supernova such as SN 1987A or the recently observed SN 2023ixf, emitted a large number of ALPs that afterwards decayed into gamma-ray photons, such a signal could have been detected by telescopes. The precise prediction of this signal is a further focus of this thesis and three of the included publications. Additionally, we improve many technical aspects of the determination of the number and energy of ALPs produced in supernovae, as well as their reabsorption before they can leave the hot and dense inner regions. This enables us to derive some of the strongest, and most reliable bounds to date on the parameters of ALPs.
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