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- Ghorbani, Morteza, et al.
(författare)
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On ``Cavitation on Chip'' in Microfluidic Devices With Surface and Sidewall Roughness Elements
- 2019
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Ingår i: Journal of microelectromechanical systems. - : Institute of Electrical and Electronics Engineers Inc.. - 1057-7157 .- 1941-0158. ; 28:5, s. 890-899
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, cavitating flows are characterized in 29 microfluidic devices in order to achieve a comprehensive perspective regarding flow patterns in microscale, which is crucial in the applications, such as energy harvesting and biomedical treatment. While the assessment of size effects is vital for the design and development of microfluidic devices involving phase change, surface/sidewall roughness and pressure pulses as a result of nanomechanical oscillations increase the performance with respect to cavitation by providing more cavitation bubbles. A typical device generates cavitating flows under different conditions (from inception to choked flow). In this device, a restrictive element and a big channel downstream of the restrictive element--where the cavitation is formed and developed--are included. The cavitating flows are obtained inside 24 sidewall roughened and 5 surface roughened/plain microfluidic devices at different pressure drops. The length and height of the sidewall roughness elements are varied to achieve the most optimum performance in terms of cavitation generation. Moreover, different surface roughened and plain devices are considered to provide a comprehensive overview of cavitation generation in microscale. The results show that sidewall roughness elements have a remarkable effect on the cavitation inception and flow patterns. [2019-0025] IEEE
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| 2. |
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| 3. |
- Motezakker, Ahmad Reza
(författare)
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Dynamics and interactions in entangled nanofibre dispersions
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biopolymers and their networks are fundamental to numerous biological and synthetic systems, with applications ranging from extracellular matrices in biological tissues to engineered nanostructured materials like cellulose-based nanocomposites. Understanding the dynamics of biopolymers in these networks is crucial due to their potential in material science and biotechnology, such as in developing sustainable materials and enhancing drug delivery mechanisms. The intricate network structures, from fibrous matrices in natural systems to designed frameworks in advanced materials, play a pivotal role in determining the mechanical and transport properties of the overall system.This thesis delves into the dynamics of biopolymers, focusing specifically on the diffusion processes within such networks. The complexity of biopolymer behavior in networked environments involves multiple factors including polymer stiffness, network structure, and the interaction between biopolymer components. The diffusion of biopolymer fibres themselves, as well as nanoparticles within these networks, is explored through detailed coarse-grained molecular dynamics simulations. These simulations aim to model the nuanced interaction dynamics that influence diffusion, providing insights into how these factors affect biopolymer networks' rheological properties and functional capabilities.This work contributes to the broader understanding of how biopolymers behave in complex environments by investigating the fundamental mechanisms of diffusion in biopolymer networks. It addresses the need for a deeper exploration of biopolymer dynamics to inform the design and synthesis of new biomaterials and bio-based materials. The findings from this thesis are expected to offer implications for enhancing the functionality of biopolymer-based systems in various applications, from improving the efficiency of biomaterials used in medical applications to optimizing the performance of bio-based composites in industrial applications.
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| 4. |
- Motezakker, Ahmad Reza, et al.
(författare)
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Effect of Stiffness on the Dynamics of Entangled Nanofiber Networks at Low Concentrations
- 2023
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 56:23, s. 9595-9603
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Tidskriftsartikel (refereegranskat)abstract
- Biopolymer network dynamics play a significant role in both biological and materials science. This study focuses on the dynamics of cellulose nanofibers as a model system given their relevance to biology and nanotechnology applications. Using large-scale coarse-grained simulations with a lattice Boltzmann fluid coupling, we investigated the reptation behavior of individual nanofibers within entangled networks. Our analysis yields essential insights, proposing a scaling law for rotational diffusion, quantifying effective tube diameter, and revealing release mechanisms during reptation, spanning from rigid to semiflexible nanofibers. Additionally, we examine the onset of entanglement in relation to the nanofiber flexibility within the network. Microrheology analysis is conducted to assess macroscopic viscoelastic behavior. Importantly, our results align closely with previous experiments, validating the proposed scaling laws, effective tube diameters, and onset of entanglement. The findings provide an improved fundamental understanding of biopolymer network dynamics and guide the design of processes for advanced biobased materials.
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| 5. |
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| 6. |
- Rosén, Tomas, 1985-, et al.
(författare)
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Exploring nanofibrous networks with x-ray photon correlation spectroscopy through a digital twin
- 2023
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Ingår i: Physical review. E. - 2470-0045 .- 2470-0053. ; 108:1
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a framework of interpreting data from x-ray photon correlation spectroscopy experiments with the aid of numerical simulations to describe nanoscale dynamics in soft matter. This is exemplified with the transport of passive tracer gold nanoparticles in networks of charge-stabilized cellulose nanofibers. The main structure of dynamic modes in reciprocal space could be replicated with a simulated system of confined Brownian motion, a digital twin, allowing for a direct measurement of important effective material properties describing the local environment of the tracers.
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