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- Fenstermacher, M.E., et al.
(author)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Journal article (peer-reviewed)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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- Thomé, Geninho, et al.
(author)
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Osseointegration of a novel injection molded 2-piece ceramic dental implant : a study in minipigs
- 2021
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In: Clinical Oral Investigations. - : Springer Science and Business Media LLC. - 1432-6981 .- 1436-3771. ; 25:2, s. 603-615
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Journal article (peer-reviewed)abstract
- Objectives: This study compared the osseointegrative potential of a novel injection molded zirconia dental implant (Neodent Zi ceramic implant, test) and a commercially available titanium implant (Neodent Alvim implant, control) in terms of histomorphometrically derived bone-to-implant contact (BIC), first bone-to-implant contact (fBIC), and the ratio of bone area to total area (BATA) around the implant. Materials and methods: A total of 36 implants, 18 per individual test device, were implanted in a split-mouth arrangement in either side of the edentulous and fully healed mandible of 6 minipigs. Histomorphometric analysis of BIC, fBIC, and BATA were performed 8 weeks post implantation and subjected to statistical non-inferiority testing. Surface characteristics of both implant types were compared in terms of contact angle, surface topography, and elemental composition. Results: BIC, fBIC, and coronal BATA values of test and control implants were statistically comparable and non-inferior. BIC values of 77.8 ± 6.9% vs. 80.7 ± 6.9% (p = 0.095) were measured for the test and control groups. fBIC lingual values were − 238 ± 328 μm compared with − 414 ± 511 μm (p = 0.121) while buccal values were − 429 ± 648 μm and − 588 ± 550 μm (p = 0.230) for the test and control devices, respectively. BATA in the apical segment was significantly higher in the test group compared with the control group (67.2 ± 11.8% vs. 59.1 ± 11.4%) (p = 0.0103). Surface topographies of both implant types were comparable. Surface chemical analysis indicated the presence of carbonaceous adsorbates which correlated with a comparable and predominantly hydrophobic character of the implants. Conclusion: The results demonstrate that the investigated zirconia implants, when compared with a commercially available titanium implant, show equivalent and non-inferior bone integration, bone formation, and alveolar bone level maintenance. This qualifies the investigated zirconia implant as a potential candidate for clinical development. Clinical relevance: This study investigated the osseointegration of a novel zirconia 2-piece dental implant prototype intended for clinical development. With the aim of translating this prototype into clinical development preclinical models, procedures and materials within this study have been selected as close to clinical practice and human physiological conditions as possible.
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