| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Alejano, L. R., et al.
(författare)
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Rock engineering design and the evolution of Eurocode 7
- 2013
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Ingår i: ISRM International Symposium - EUROCK 2013. - : International Society for Rock Mechanics. - 9781138000803 ; , s. 777-782
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Konferensbidrag (refereegranskat)abstract
- The Eurocode for Geotechnical Design, EN-1997-1:2004, informally known as Eurocode 7 or EC7, was fully implemented within the European Union in 2010. This Eurocode is intended to apply to all geotechnical engineering design, including rock engineering. In recognition that all codes must continue to evolve in order to remain applicable, and the long time that such evolution takes, work is already underway under the auspices of the European Committee for Standardisation, CEN, to identify how the code should develop for future revisions. This paper presents a summary of the maintenance procedures for Eurocodes in general and the specific maintenance work currently being undertaken on EC7 in respect of rock engineering design. It also highlights potential future development of EC7, and the need for enthusiastic involvement by the European rock engineering community to direct these developments.
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| 3. |
- Harrison, J. P., et al.
(författare)
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Rock engineering design and the evolution of Eurocode 7 : The critical six years to 2020
- 2017
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Ingår i: 13th ISRM International Congress of Rock Mechanics. - : International Society for Rock Mechanics. - 9781926872254
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Konferensbidrag (refereegranskat)abstract
- In 2010, the Eurocode for Geotechnical Design, EN-1997-1:2004 (CEN, 2004), informally known as Eurocode 7 or EC7, became the Reference Design Code (RDC) for geotechnical design - including rock engineering design - within the European Union (EU). EC7 is one standard within the comprehensive Structural Eurocode suite, which as a whole has been also adopted by a number of other countries beyond the EU. EC7 is thus becoming a key design standard for geotechnical engineering worldwide. As part of the Structural Eurocode suite, EC7 requires designs to adhere to the principles of Limit State Design. However, it is not clear that current rock engineering design practice can satisfy this requirement. In addition, evidence is accumulating that EC7 is currently difficult to apply to, and may even be inappropriate for, rock engineering design. These issues may be due to the fact that the development of EC7 to date took place without any formal input from the international rock mechanics and rock engineering community. In early 2011 under the auspices of CEN (Comité Européen de Normalisation / European Committee for Standardisation), EC7 entered a formal period of maintenance which was aimed at improving the applicability and ease-of-use of the Code. This maintenance cycle will conclude in 2020 with the publication of a revised version of EC7. This paper describes a number of critical aspects for rock engineering in the context of EC7, in particular the following: - the history of the Structural Eurocodes and the concepts they embody; - the nature of Limit State Design and the challenges and opportunities it poses for rock engineering design; - the formal means by which the Structural Eurocode maintenance cycle proceeds; - the plans currently being developed for improving EC7 with regard to rock engineering design and construction; - the unique and vital opportunity for the entire international rock mechanics and rock engineering community to comment on the Code and make suggestions for its improvement.
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| 4. |
- Annadi, A., et al.
(författare)
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Anisotropic two-dimensional electron gas at the LaAlO3/SrTiO3 (110) interface
- 2013
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The observation of a high-mobility two-dimensional electron gas between two insulating complex oxides, especially LaAlO3/SrTiO3, has enhanced the potential of oxides for electronics. The occurrence of this conductivity is believed to be driven by polarization discontinuity, leading to an electronic reconstruction. In this scenario, the crystal orientation has an important role and no conductivity would be expected, for example, for the interface between LaAlO3 and (110)-oriented SrTiO3, which should not have a polarization discontinuity. Here we report the observation of unexpected conductivity at the LaAlO3/SrTiO3 interface prepared on (110)-oriented SrTiO3, with a LaAlO3-layer thickness-dependent metal-insulator transition. Density functional theory calculation reveals that electronic reconstruction, and thus conductivity, is still possible at this (110) interface by considering the energetically favourable (110) interface structure, that is, buckled TiO2/LaO, in which the polarization discontinuity is still present. The conductivity was further found to be strongly anisotropic along the different crystallographic directions with potential for anisotropic superconductivity and magnetism, leading to possible new physics and applications.
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| 5. |
- Abrahamsson, Thomas, 1956, et al.
(författare)
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Calibration and Validation of a Car Subframe Finite Element Model Using Frequency Responses
- 2015
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Ingår i: Conference Proceedings of the Society for Experimental Mechanics Series. - Cham : Springer International Publishing. - 2191-5644 .- 2191-5652. - 9783319152516 ; , s. 9-22
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Konferensbidrag (refereegranskat)abstract
- A finite element model of a car front subframe has been calibrated against test data. Stepped-sine testing has been used to give frequency response function estimates on an ensemble of seemingly identical subframes. Therefore, the deviation between test data and simulation results can be compared in a meaningful way by the outcome of model calibration and cross-validation. Emphasis has been put on the preparation of the test pieces for high fidelity testing and on bettering the chances of getting a calibration outcome that provides insight into the physical processes that govern the subframe dynamics. The front subframe model has more than 200,000 degrees-of-freedom and 17 model calibration parameters. The efficiency of the calibration procedure under these conditions is reported. To achieve efficiency, a calibration with a smooth deviation metric is used together with a damping equalization method that eliminates the need for matching of experimental and analytical eigenmodes. The method is combined with surrogate model frequency response evaluation based on model reduction for increased speed. The Matlab based open-domain software tool FEMcali that employs the Levenberg-Marquardt minimizer with randomized starts has been used for calibration and an unregularized Gauss-Newton minimizer has been used in the cross-validation.
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| 6. |
- Gilbert, M. R., et al.
(författare)
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Perspectives on multiscale modelling and experiments to accelerate materials development for fusion
- 2021
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 554
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Forskningsöversikt (refereegranskat)abstract
- Prediction of material performance in fusion reactor environments relies on computational modelling, and will continue to do so until the first generation of fusion power plants come on line and allow long-term behaviour to be observed. In the meantime, the modelling is supported by experiments that attempt to replicate some aspects of the eventual operational conditions. In 2019, a group of leading experts met under the umbrella of the IEA to discuss the current position and ongoing challenges in modelling of fusion materials and how advanced experimental characterisation is aiding model improvement. This review draws from the discussions held during that workshop. Topics covering modelling of irradiation-induced defect production and fundamental properties, gas behaviour, clustering and segregation, defect evolution and interactions are discussed, as well as new and novel multiscale simulation approaches, and the latest effort s to link modelling to experiments through advanced observation and characterisation techniques.
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| 7. |
- Asgari, H., et al.
(författare)
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Effect of yttrium on the twinning and plastic deformation of AE magnesium alloy under ballistic impact
- 2015
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - : Elsevier BV. - 0921-5093. ; 623, s. 10-21
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Tidskriftsartikel (refereegranskat)abstract
- In this research, effect of yttrium on the texture formation, microstructural evolution and mechanical response of AE42 and AE44 cast magnesium alloys were investigated under ballistic impact. The selected strain rates were 800 and 1100 s(-1) and the tests were conducted using Split Hopkinson Pressure Bar. It was inferred that after high velocity impact, a weaker basal texture developed in the samples with lower content of yttrium. Experimental results also showed that by increasing the concentration of yttrium in the cast AE alloys, strength, ductility and dislocation density of the impacted alloys increased but, the fraction of twinning decreased, which indicate the effective influence of yttrium on the nucleation and growth of twins. Moreover, it was inferred that accumulation of dislocations at intersections of the twins led to the cracking and fracture of the samples under shock loading conditions.
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| 8. |
- Asgari, H., et al.
(författare)
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Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading
- 2015
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Ingår i: Materials Characterization. - : Elsevier BV. - 1044-5803. ; 106, s. 359-367
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Tidskriftsartikel (refereegranskat)abstract
- The effects of grain size on the dynamic deformation behavior of rolled AZ31B alloy at high strain rates were investigated. Rolled AZ31B alloy samples with grain sizes of 6,18 and 37 pm, were subjected to shock loading tests using Split Hopkinson Pressure Bar at room temperature and at a strain rate of 1100 s(-1) It was found that a double-peak basal texture formed in the shock loaded samples. The strength and ductility of the alloy under the high strain-rate compressive loading increased with decreasing grain size. However, twinning fraction and strain hardening rate were found to decrease with decreasing grain size. In addition, orientation imaging microscopy showed a higher contribution of double and contraction twins in the deformation process of the coarse-grained samples. Using transmission electron microscopy, pyramidal dislocations were detected in the shock loaded sample, proving the activation of pyramidal slip system under dynamic impact loading.
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| 9. |
- Olsson, Gustaf, et al.
(författare)
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Instrumentation, control and automation in wastewater – from London 1973 to Narbonne 2013
- 2014
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 69:7, s. 1373-1385
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Tidskriftsartikel (refereegranskat)abstract
- Key developments of instrumentation, control and automation (ICA) applications in wastewater systems during the past 40 years are highlighted in this paper. From the first ICA conference in 1973 through to today there has been a tremendous increase in the understanding of the processes, instrumentation, computer systems and control theory. However, many developments have not been addressed here, such as sewer control, drinking water treatment and water distribution control. It is hoped that this review can stimulate new attempts to more effectively apply control and automation in water systems in the coming years.
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| 10. |
- Toijer, Elin, et al.
(författare)
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Ab initio modelling of intergranular fracture of nickel containing phosphorus : Interfacial excess properties
- 2021
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Ingår i: Nuclear Materials and Energy. - : Elsevier BV. - 2352-1791. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, the impact of phosphorus impurities on the grain boundary strength of nickel has been investigated by means of density functional theory (DFT) modelling. Owing to different outcomes and trends previously reported in the literature, it is unclear whether P is strengthening or weakening the Ni grain boundary. To address this issue, we utilize three different DFT based methods: the excess-energy approach, rigid grain separation, and Rice-Wang's thermodynamic approach. The results show that the commonly used rigid model predicts P to have an increasing effect on the peak stress of Ni of up to 14%, as opposed to a reduction, which is indicated by the excess-energy approach. Employment of the Rice-Wang approach, on the other hand, displays a slight reduction in work of separation. The results show that the discrepancies between previous works can be attributed not so much to the physics of the system, but to the applied model, the partition scheme and the interpretation of the outcomes. This underlines the importance of a proper description of the fracture process, and shows that common simplifications can have a decisive impact on the observed trends.
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