| 1. |
- Amini, Kasra, et al.
(författare)
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Challenges in illumination analysis and design for Martian surface-level habitation
- 2024
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Ingår i: MethodsX. - : Elsevier BV. - 1258-780X .- 2215-0161. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- It is needless to say that travel to and settlement on Mars are associated with extreme levels of scientific and engineering issues. This will only be amplified with the long-term duration of the mission, not only due to scarcity of resources, but also as the psychological aspects of the dynamics among the crew increase drastically. It should be emphasized that this is a scientific crew, who have undergone high levels of confinement during space travel to Mars, O (102 Earth days), are living in semi-solitude and partial confinement conditions for durations of O (103 Earth days), and even at the nominal termination of the mission, foresee a high-risk and arduous travel time of O (102 Earth days) back to the Earth. The mental weight of the described mission with its slow pace and tardy episodes, puts the crew under severe psychological issues. Minimal and conservative design of spaces, lack of constant access to the exterior, and social solitude are among major factors contributing to the psychological well-being of the crew. Furthermore, the overall lower levels of natural light, accompanied by the minimum possible area of transparent facades, protecting the crew from harmful radiations and cold exterior, burden the mental conditions of the crew even more. Given the limited availability of data from the surface of Mars, study of the effects linked to the lighting and illumination design of the habitats is challenging. The current manuscript hopes to shed light on the illumination and lighting design and simulation procedure, required data, assumptions, and final results for the surface-level habitats on Mars. • Mars / Sub orbital configuration allows for limited natural lighting, however, upon site-specific analysis, it might be considerable as a base passive source. • Current simulation tools are design based on Earth-bound design requirements. These need to be re-oriented to match available planetary data.
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| 2. |
- Amini, Kasra, et al.
(författare)
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Scaling laws for near-wall flows of thixo-elasto-viscoplastic fluids in a millifluidic channel
- 2024
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Ingår i: Physics of fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 36:2
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Tidskriftsartikel (refereegranskat)abstract
- Thixo-elasto-viscoplastic (TEVP) fluids are very complex fluids. In addition to elasticity and viscoplasticity, they exhibit thixotropy, i.e., time-dependent rheology due to breakdown and recovery of internal structures at different length- and timescales. General and consistent methods for a priori flow prediction of TEVP fluids based on rheological characteristics are yet to be developed. We report a combined study of the rheology and flow of 18 samples of different TEVP fluids (three yogurts and three concentrations of Laponite and Carbopol, respectively, in water in both the unstirred and a stirred state). The rheology is determined both with standard protocols and with an ex situ protocol aiming at reproducing the shear history of the fluid in the flow. Micrometer resolution flow measurements in a millimeter scale rectangular duct are performed with Doppler Optical Coherence Tomography (D-OCT). As expected, the results show the existence of a plug flow region for samples with sufficiently high yield stress. At low flow rates, the plug extends almost all the way to the wall and the extent of the plug decreases not only with increased flow rate but also with increased thixotropy. The ex situ rheology protocol enables estimation of the shear rate and shear stress close to the wall, making it possible to identify two scaling laws that relates four different non-dimensional groups quantifying the key properties wall-shear stress and slip velocity. The scaling laws are suggested as an ansatz for a priori prediction of the near-wall flow of TEVP fluids based on shear flow-curves obtained with a rheometer.
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| 3. |
- Tanriverdi, Selim, et al.
(författare)
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Elasto-inertial focusing and particle migration in high aspect ratio microchannels for high-throughput separation
- 2024
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Ingår i: Microsystems and Nanoengineering. - : Springer Nature. - 2055-7434. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The combination of flow elasticity and inertia has emerged as a viable tool for focusing and manipulating particles using microfluidics. Although there is considerable interest in the field of elasto-inertial microfluidics owing to its potential applications, research on particle focusing has been mostly limited to low Reynolds numbers (Re<1), and particle migration toward equilibrium positions has not been extensively examined. In this work, we thoroughly studied particle focusing on the dynamic range of flow rates and particle migration using straight microchannels with a single inlet high aspect ratio. We initially explored several parameters that had an impact on particle focusing, such as the particle size, channel dimensions, concentration of viscoelastic fluid, and flow rate. Our experimental work covered a wide range of dimensionless numbers (0.05 < Reynolds number < 85, 1.5 < Weissenberg number < 3800, 5 < Elasticity number < 470) using 3, 5, 7, and 10 µm particles. Our results showed that the particle size played a dominant role, and by tuning the parameters, particle focusing could be achieved at Reynolds numbers ranging from 0.2 (1 µL/min) to 85 (250 µL/min). Furthermore, we numerically and experimentally studied particle migration and reported differential particle migration for high-resolution separations of 5 µm, 7 µm and 10 µm particles in a sheathless flow at a throughput of 150 µL/min. Our work elucidates the complex particle transport in elasto-inertial flows and has great potential for the development of high-throughput and high-resolution particle separation for biomedical and environmental applications. (Figure presented.)
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