Multiloop matter-wave interferometers are essential in quantum sensing to measure the derivatives of physical quantities in time or space. Because multiloop interferometers require multiple ...reflections, imperfections of the matter-wave mirrors create spurious paths that scramble the signal of interest. Here, we demonstrate a method of adjustable momentum transfer that prevents the recombination of the spurious paths in a double-loop atom interferometer aimed at measuring rotation rates. We experimentally study the recombination condition of the spurious matter waves, which is quantitatively supported by a model accounting for the coherence properties of the atomic source. We finally demonstrate the effectiveness of the method in building a cold-atom gyroscope with a single-shot acceleration sensitivity suppressed by a factor of at least 50. Our study will impact the design of multiloop atom interferometers that measure a single inertial quantity.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
The change of multivalence band structure configuration between rhombohedral and cubic phase in GeTe offers additional dimension to modify its thermoelectric properties. Here, we report the ...synergetic optimization of electronic and thermal transport properties in rhombohedral GeTe doped with transition metal Ti. The Seebeck coefficient of Ge1-xTixTe is significantly increased, and the corresponding thermal conductivity is decreased. The structure refinement shows that Ti doping could reduce the lattice constant c/a ratio. Density functional theory calculations demonstrate that the affected crystal field rather than Ti orbitals is contributing to the valence band convergence and a Seebeck coefficient enhancement. Further optimization incorporates the effects of Bi substitution for reducing the carrier concentrations and introducing more point defects. This work not only confirms the transition metal elements as promising dopants for GeTe-based materials but also indicates that the strategy of manipulating the crystal field effect can be exploited as a direct but effective route for improving thermoelectric performance.
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•Enhanced Seebeck coefficient and decreased thermal conductivity upon Ti doping.•Further optimized by decreasing carrier concentration and lattice thermal conductivity with co-doping Bi and Ti at Ge sites.•Proof of manipulation of crystal field effect as a feasible route of band engineering for thermoelectric enhancement of GeTe.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► A reference solution is provided for one of the most popular benchmark in CFD. ► Highly accurate numerical methods are used with a new set of boundary conditions. ► A user-friendly file gives the ...solution at any location with the spectral accuracy. ► Body-fitted and immersed boundary approaches are compared. ► Numerical errors and convergence for the velocity and the pressure are investigated.
The classical problem of the flow over a circular cylinder at Reynolds number 40 is considered using an accurate pseudo-spectral code. A new set of boundary conditions is proposed to improve the representation of the infinite flow domain, especially in the far wake area. It is shown that the resulting accuracy of the computed flow allows its use as a reference solution for code validation. This reference solution is reachable at any location up to 50 cylinder diameters far from the cylinder centre through spectral interpolation with a user-friendly script provided in appendix. It is shown how this solution offers the opportunity to perform a convergence study and to investigate the spatial distribution of numerical errors. The main goal of this study is to propose this reference solution as an helpful tool for numerical validation and development, especially for the improvement of immersed boundary methods toward high-order accuracy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•A new validated 3D CFD model for pressure-swing-adsorption.•Heat and mass transfers in porous media in presence of adsorption.•CO2-CH4 gas separation process modeling including local bed ...information.
A 3D Computational Fluid Dynamics (CFD) model is developed, applied and validated for a 4-steps PSA cycle operating for CO2/CH4 separation by using Carbon Molecular Sieves (CMS). The computational results are addressed and found to be in good agreement with experimental data. The Linear Driving Force (LDF) model is employed in the present 3D CFD approach to compute the adsorption/desorption rates in the packed bed. The physical parameters which are crucial for better predicting the behavior of a PSA cycle at different operating conditions are identified. The present developed 3D CFD model of PSA processes will serve as a powerful optimization tool in CFD to enhance and create future optimal designs of gas separation systems operating simultaneously in both temperature and pressure swing.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
SABBAC is an on-line service devoted to protein backbone reconstruction from alpha-carbon trace. It is based on the assembly of fragments taken from a library of reduced size, selected from the ...encoding of the protein trace in a hidden Markov model-derived structural alphabet. The assembly of the fragments is achieved by a greedy algorithm, using an energy-based scoring. Alpha-carbon coordinates remain unaffected. SABBAC simply positions the missing backbone atoms, no further refinement is performed. From our tests, SABBAC performs equal or better than other similar on-line approach and is robust to deviations on the alpha-carbon coordinates. It can be accessed at http://bioserv.rpbs.jussieu.fr/SABBAC.html.
•3D CFD model for simulating adsorption process cycles: sensitivity analysis.•Parameters influence on heat and mass transfers in porous media in presence of adsorption.•Effect of effective thermal ...conductivity of the porous medium.•Influence of the mass transfer coefficient and the column dead volumes.•Effect of the equilibrium isotherm model choice on PSA cycle 3D CFD simulations.
In the present manuscript, a numerical sensitivity analysis is conducted on different physical parameters in order to assess the robustness of a 3D CFD simulation of adsorption process cycles. It is demonstrated that the effective thermal conductivity of the porous medium, the mass transfer coefficient, the column dead volumes, the equilibrium isotherm model choice, are all crucial parameters to model accurately adsorption kinematics and heat transfer through a packed porous bed using 3D CFD approach. Moreover, it is found that the initial condition imposed on the adsorbed phase at the start of a steady PSA cycle, is a crucial point to predict accurately the mass transfer and the displacement of the adsorption front in 3D CFD computations.
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GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We have investigated the developmental relationship of the hemopoietic and endothelial lineages in the floor of the chicken aorta, a site of hemopoietic progenitor emergence in the embryo proper. We ...show that, prior to the onset of hemopoiesis, the aortic endothelium uniformly expresses the endothelium-specific membrane receptor VEGF-R2. The onset of hemopoiesis can be determined by detecting the common leukocyte antigen CD45. VEGF-R2 and CD45 are expressed in complementary fashion, namely the hemopoietic cluster-bearing floor of the aorta is CD45(+)/VEGF-R2(â), while the rest of the aortic endothelium is CD45(â)/VEGF-R2(+). To determine if the hemopoietic clusters are derived from endothelial cells, we tagged the E2 endothelial tree from the inside with low-density lipoproteins (LDL) coupled to DiI. 24 hours later, hemopoietic clusters were labelled by LDL. Since no CD45(+) cells were inserted among endothelial cells at the time of vascular labelling, hemopoietic clusters must be concluded to derive from precursors with an endothelial phenotype.
Adult-type hematopoietic stem and progenitor cells are formed during ontogeny from a specialized subset of endothelium, termed the hemogenic endothelium, via an endothelial-to-hematopoietic ...transition (EHT) that occurs in the embryonic aorta and the associated arteries. Despite efforts to generate models, little is known about the mechanisms that drive endothelial cells to the hemogenic fate and about the subsequent molecular control of the EHT. Here, we have designed a stromal line-free controlled culture system utilizing the embryonic pre-somitic mesoderm to obtain large numbers of endothelial cells that subsequently commit into hemogenic endothelium before undergoing EHT. Monitoring the culture for up to 12 days using key molecular markers reveals stepwise commitment into the blood-forming system that is reminiscent of the cellular and molecular changes occurring during hematopoietic development at the level of the aorta. Long-term single-cell imaging allows tracking of the EHT of newly formed blood cells from the layer of hemogenic endothelial cells. By modifying the culture conditions, it is also possible to modulate the endothelial cell commitment or the EHT or to produce smooth muscle cells at the expense of endothelial cells, demonstrating the versatility of the cell culture system. This method will improve our understanding of the precise cellular changes associated with hemogenic endothelium commitment and EHT and, by unfolding these earliest steps of the hematopoietic program, will pave the way for future ex vivo production of blood cells.
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