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| 2. |
- Lewin, Susanne, et al.
(författare)
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Mechanical behaviour of composite calcium phosphate-titanium cranial implants : Effects of loading rate and design
- 2020
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Ingår i: Journal of The Mechanical Behavior of Biomedical Materials. - : Elsevier BV. - 1751-6161 .- 1878-0180. ; 104
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Tidskriftsartikel (refereegranskat)abstract
- Cranial implants are used to repair bone defects following neurosurgery or trauma. At present, there is a lack of data on their mechanical response, particularly in impact loading. The aim of the present study was to assess the mechanical response of a recently developed composite calcium phosphate-titanium (CaP-Ti) implant at quasi-static and impact loading rates. Two different designs were tested, referred to as Design 1 (D1) and Design 2 (D2). The titanium structures in the implant specimens were additively manufactured by a powder-bed fusion process and subsequently embedded in a self-setting CaP material. D1 was conceptually representative of the clinically used implants. In D2, the titanium structure was simplified in terms of geometry in order to facilitate the manufacturing. The mechanical response of the implants was evaluated in quasi-static compression, and in impact using a drop-tower. Similar peak loads were obtained for the two designs, at the two loading rates: 808 ± 29 N and 852 ± 34 for D1, and 840 ± 40 N and 814 ± 13 for D2. A strain rate dependency was demonstrated for both designs, with a higher stiffness in the impact test. Furthermore, the titanium in the implant fractured in the quasi-static test (to failure) but not in the impact test (to 5.75 J) for D1. For D2, the displacement at peak load was significantly lower in the impact test than in the quasi-static test. The main difference between the designs was seen in the quasi-static test results where the deformation zones, i.e. notches in the titanium structure between the CaP tiles, in D1 likely resulted in a localization of the deformation, compared to in D2 (which did not have deformation zones). In the impact test, the only significant difference between the designs was a higher maximum displacement of D2 than of D1. In comparison with other reported mechanical tests on osteoconductive ceramic-based cranial implants, the CaP-Ti implant demonstrates the highest reported strength in quasi-static compression. In conclusion, the titanium structure seems to make the CaP-Ti implant capable of cerebral protection in impact situations like the one tested in this study.
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| 3. |
- Emmanuel, Max, et al.
(författare)
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Fracture Energy Measurement of Prismatic Plane and Σ2 Boundary in Cemented Carbide
- 2021
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 73:6, s. 1589-1596
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Tidskriftsartikel (refereegranskat)abstract
- The grain boundary network of WC in WC-Co is important, as cracks often travel intergranularly. This motivates the present work, where we experimentally measure the fracture energy of Σ2 twist grain boundaries between WC crystals using a double cantilever beam opened with a wedge under displacement control in a WC-10wt%Co sample. The fracture energy of this boundary type was compared with cleaving {10 1 ¯ 0 } prismatic planes in a WC single crystal. Fracture energies of 7.04 ± 0.36 Jm−2 and 3.57 ± 0.28 Jm−2 were measured for {10 1 ¯ 0 } plane and Σ2 twist boundaries, respectively.
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| 4. |
- Ghandour, Salim, et al.
(författare)
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A model for the biomechanical assessment of discoplasty in a laboratory setting
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Percutaneous cement discoplasty is a spinal surgical technique which has been rarely tested outside the clinical setting. This study aimed at developing an ovine model framework to allow testing and optimization of discoplasty in a lab-controlled environment.
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| 5. |
- Ghandour, Salim, et al.
(författare)
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An ex-vivo Biomechanical Assessment of Cement Discoplasty
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Spinal fusion is the golden standard for treating degenerative disc disease. However, elderly patients with underlying chronic conditions cannot undergo spinal fusion due to healing impairment, risks of infection, and/or even morbidity. Percutaneous Cement Discoplasty (PCD) is a relatively new procedure that involves injecting poly(methyl methacrylate) (PMMA) cement into the disc to reduce pain and attempt to maintain spinal curvature and height. Therefore, this minimally invasive method could be an advantageous option for patients for whom open surgery is deemed too risky [1]. While this technique has already been attempted clinically, to the authors knowledge, only one preliminary study on the biomechanics of PCD is currently available [2]. This study aims to develop a more clinically relevant and repeatable method to study PCD in a lab setting. To this end, ovine spine was tested in three different categories: healthy disc; injured disc; treated disc. A papain enzyme solution [3] was used to create the vacuum phenomena in the sheep spine to represent the injury as observed in a clinical setting. Preliminary compression testing showed promising results with a significant increase in stability of the segments after treatment. Further on, this testing method can be used to test different materials, surgical methods and biomechanical behaviour to further advance PCD.
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| 8. |
- Åkesson, Lynn, et al.
(författare)
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Fastighetsnära källsortering ur de boendes perspektiv : blev det lätt och rätt?
- 2020
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Ingår i: Ekostaden Augustenborg : erfarenheter och lärdomar - erfarenheter och lärdomar. - 9789151978673 ; 78, s. 234-244
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Bokkapitel (refereegranskat)abstract
- Studien handlar om hur de som bor i stadsdelen Augustenborg i Malmö använde och upplevde den avfallshantering som introducerades 2008. Hur hållbara avfallssystem kan åstadkommas diskuteras med utgångspunkt i användning och upplevelse av den lokala avfallshanteringen. De primära frågeställningarna är:• Vilka begrepp och kategorier skapar och använder invånarna när det gäller avfall i vardagen? Hur fungerar dessa kategorier i praktiken när avfall ska sorteras, hur lärs de in och blir till självklarheter?• Hur väl fungerar källsorteringen? Hur mycket är sorterat och hur mycket är korrekt sorterat?• Hur förhåller sig invånarnas sätt att tänka om källsortering och deras faktiska agerande, till det sorteringssystem som finns i Augustenborg? Finns det lärdomar att dra om hur klyftan mellan avfallssystemet och användarnas uppfattningar och vanor kan överbryggas?
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| 9. |
- Borgh, Ida, et al.
(författare)
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Microstructure, grain size distribution and grain shape in WC-Co alloys sintered at different carbon activities
- 2014
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Ingår i: International journal of refractory metals & hard materials. - : Elsevier BV. - 0263-4368 .- 0958-0611. ; 43, s. 205-211
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Tidskriftsartikel (refereegranskat)abstract
- The properties of cemented carbides strongly depend on the WC grain size and it is thus crucial to control coarsening of WC during processing. The aim of this work was to study the effect of sintering at different carbon activities on the final microstructure, as well as the coarsening behavior of the WC grains, including the size distribution and the shape of WC grains. These aspects were investigated for five WC-Co alloys sintered at 1410 degrees C for 1 h at different carbon activities in the liquid, in the range from the graphite equilibrium (carbon activity of 1) to the eta (M6C) phase equilibrium (carbon activity of 0.33). The grain size distribution was experimentally evaluated for the different alloys using EBSD (electron backscatter diffraction). In addition, the shape of the WC grains was evaluated for the different alloys. It was found that the average WC grain size increased and the grain size distribution became slightly wider with increasing carbon activity. Comparing the two three-phase (WC-Co-eta and WC-Co-graphite) alloys a shape change of the WC grains was observed with larger grains having more planar surfaces and more triangular shape for the WC-Co-graphite alloy. It was indicated that in alloys with a relatively low volume fraction of the binder phase the WC grain shape is significantly affected by impingements. Moreover, after 1 h of sintering the WC grains are at a non-equilibrium state with regards to grain morphology. (C) 2013 Elsevier Ltd. All rights reserved.
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| 10. |
- Fahrenkrog, Felix, et al.
(författare)
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Impact Assessment of Developed Applications – Overall interactIVe Assessment
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- interactIVe introduces active intervention safety systems in order to increase traffic safety. The interactIVe functions are – depending on their purpose – able to brake and steer autonomously. Furthermore, the driver is continuously supported by interactIVe assistance systems which warn the driver in potentially dangerous situations. Seven demonstrator vehicles – six passenger cars of different vehicle classes and one truck - are built up in interactIVe to develop, test, and evaluate the next generation of safety systems. The three vertical subprojects in interactIVe SECONDS, INCA and EMIC have developed 11 different functions with a wide range of target areas. The developed advanced driver assistance systems (ADAS) comprise the following systems: • SP4 “SECONDS” dealing with functions, which support the driver continuously in the driving process. These functions should not only support the driver in dangerous situations, but help the driver to avoid them. • SP5 “INCA” dealing with functions, which combine longitudinal and lateral control of the vehicle in order to prevent imminent accidents. The INCA functions’ focus is not only on the collision avoidance in rear-end conflicts, but also on other types of conflicts, such as blind-spot and road departure situations. • SP6 “EMIC” deals with critical pre-crash applications, where collision mitigation can be realised at a reasonable cost. In order to evaluate the ADAS developed, an evaluation framework is required. Therefore, the subproject “Evaluation and Legal Aspects” is part of the interactIVe project, which has as main objective to provide this framework and to support the vertical subprojects in their evaluation work. The evaluation of the interactIVe functions has been divided into three main categories: • Technical Assessment to evaluate the performance of the developed functions and collect information and data for safety impact assessment. • User-Related Assessment to assess the functions from the user perspective, and also to provide further input to the safety impact assessment. • Impact Assessment to estimate how and how much the functions influence traffic safety. In this deliverable, the results of the evaluation in interactIVe are presented.
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