| 1. |
- Haviland, David B., et al.
(författare)
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Probing viscoelastic response of soft material surfaces at the nanoscale
- 2016
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Ingår i: Soft Matter. - : Royal Society of Chemistry. - 1744-683X .- 1744-6848. ; 12:2, s. 619-624
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Tidskriftsartikel (refereegranskat)abstract
- We study the interaction between an AFM tip and a soft viscoelastic surface. Using a multifrequency method we measure the amplitude-dependence of the cantilever dynamic force quadratures, which clearly show the effect of finite relaxation time of the viscoelastic surface. A model is introduced which treats the tip and surface as a two-body dynamic problem with a nonlinear interaction depending on their separation. We find good agreement between simulations of this model and experimental data on polymer blend samples for a variety of materials and measurement conditions.
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| 2. |
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| 3. |
- Kassa, Hailu G., et al.
(författare)
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Nano-mechanical properties of interphases in dynamically vulcanized thermoplastic alloy
- 2018
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Ingår i: Polymer. - : ELSEVIER SCI LTD. - 0032-3861 .- 1873-2291. ; 135, s. 348-354
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Tidskriftsartikel (refereegranskat)abstract
- We present a high-resolution study of the viscoelastic response of a thermoplastic alloy using a multi-frequency method called intermodulation atomic force microscopy. We quantitatively characterize the response in terms of calibrated dynamic force quadrature curves, showing the conservative and dissipative forces at each image pixel as functions of the oscillation amplitude for industrial polymer blends.
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| 4. |
- Kim, HyeJin, et al.
(författare)
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Towards a better future for biodiversity and people : Modelling Nature Futures
- 2023
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Ingår i: Global Environmental Change. - 0959-3780 .- 1872-9495. ; 82
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Tidskriftsartikel (refereegranskat)abstract
- The Nature Futures Framework (NFF) is a heuristic tool for co-creating positive futures for nature and people. It seeks to open up a diversity of futures through mainly three value perspectives on nature - Nature for Nature, Nature for Society, and Nature as Culture. This paper describes how the NFF can be applied in modelling to support decision-making. First, we describe key considerations for the NFF in developing qualitative and quantitative scenarios: i) multiple value perspectives on nature as a state space where pathways improving nature toward a frontier can be represented, ii) mutually reinforcing key feedbacks of social-ecological systems that are important for nature conservation and human wellbeing, iii) indicators of multiple knowledge systems describing the evolution of complex social-ecological dynamics. We then present three approaches to modelling Nature Futures scenarios in the review, screening, and design phases of policy processes. This paper seeks to facilitate the integration of relational values of nature in models and strengthen modelled linkages across biodiversity, nature's contributions to people, and quality of life.
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| 5. |
- Leclere, David, et al.
(författare)
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Bending the curve of terrestrial biodiversity needs an integrated strategy
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 585:7826, s. 551-556
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Tidskriftsartikel (refereegranskat)abstract
- Increased efforts are required to prevent further losses to terrestrial biodiversity and the ecosystem services that it provides(1,2). Ambitious targets have been proposed, such as reversing the declining trends in biodiversity(3); however, just feeding the growing human population will make this a challenge(4). Here we use an ensemble of land-use and biodiversity models to assess whether-and how-humanity can reverse the declines in terrestrial biodiversity caused by habitat conversion, which is a major threat to biodiversity(5). We show that immediate efforts, consistent with the broader sustainability agenda but of unprecedented ambition and coordination, could enable the provision of food for the growing human population while reversing the global terrestrial biodiversity trends caused by habitat conversion. If we decide to increase the extent of land under conservation management, restore degraded land and generalize landscape-level conservation planning, biodiversity trends from habitat conversion could become positive by the mid-twenty-first century on average across models (confidence interval, 2042-2061), but this was not the case for all models. Food prices could increase and, on average across models, almost half (confidence interval, 34-50%) of the future biodiversity losses could not be avoided. However, additionally tackling the drivers of land-use change could avoid conflict with affordable food provision and reduces the environmental effects of the food-provision system. Through further sustainable intensification and trade, reduced food waste and more plant-based human diets, more than two thirds of future biodiversity losses are avoided and the biodiversity trends from habitat conversion are reversed by 2050 for almost all of the models. Although limiting further loss will remain challenging in several biodiversity-rich regions, and other threats-such as climate change-must be addressed to truly reverse the declines in biodiversity, our results show that ambitious conservation efforts and food system transformation are central to an effective post-2020 biodiversity strategy. To promote the recovery of the currently declining global trends in terrestrial biodiversity, increases in both the extent of land under conservation management and the sustainability of the global food system from farm to fork are required.
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| 6. |
- Thorén, Per-Anders, et al.
(författare)
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Modeling and Measuring Viscoelasticity with Dynamic Atomic Force Microscopy
- 2018
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Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between a rapidly oscillating atomic-force-microscope tip and a soft-material surface is described with use of both elastic and viscous forces in a moving-surface model. We present the simplest form of this model, motivating our derivation with the models ability to capture the impact dynamics of the tip and sample with an interaction consisting of two components: interfacial or surface force, and bulk or volumetric force. Analytic solutions to the piecewise linear model identify characteristic time constants, providing a physical explanation for the hysteresis observed in the measured dynamic-force-quadrature curves. Numerical simulation is used to fit the model to experimental data, and excellent agreement is found with a variety of different samples. The model parameters form a dimensionless impact-rheology factor, giving a quantitative physical number to characterize a viscoelastic surface that does not depend on the tip shape or cantilever frequency.
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| 7. |
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