High resolution imaging by secondary ion mass spectrometry and atom probe tomography have been employed to investigate boron segregation at austenite grain boundaries (γGBs) after soaking in a ...high-strength low-carbon steel. The combined use of these two analytical techniques is shown to be powerful for quantifying solute and segregated boron levels. Quenching was performed after soaking aiming to clarify the temperature effect on boron distribution under thermal equilibrium. Boron depletion in the γGBs vicinity was observed in the as-quenched states from high temperatures, suggesting that the cooling rate was not fast enough to limit boron diffusion during cooling. We found that boron segregation at γGBs increases with temperature. This is due to the increase of solute boron concentration in the grains, resulting from boride precipitate dissolution. It appears that the segregation magnitude still follows the equilibrium laws as a function of temperature. From our investigations, it was possible to determine the boron equilibrium segregation enthalpy. These results have important practical consequences for controlling the levels of segregated boron in steels.
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The computation of multiphase flows presents a subtle energetic equilibrium between potential (i.e., surface) and kinetic energies. The use of traditional interface-capturing schemes provides no ...control over such a dynamic balance. In the spirit of the well-known symmetry-preserving and mimetic schemes, whose physics-compatible discretizations rely upon preserving the underlying mathematical structures of the space, we identify the corresponding structure and propose a new discretization strategy for curvature. The new scheme ensures conservation of mechanical energy (i.e., surface plus kinetic) up to temporal integration. Inviscid numerical simulations are performed to show the robustness of such a method.
•Surface and kinetic energy transfers are governed by the First Variation of Area.•The use of the conservative level set smooth marker results in compatible energy transfers.•Curvature interpolation is linked with marker's advection to preserve energy.•Preserving discrete energy transfers resemble the physical model.•Current recompression schemes break physical balance between surface and kinetic energy.
There are conflicting data on the effect of a gluten-free diet (GFD) on the nutritional status of celiac patients. In the present study, we evaluated, in adult celiac patients, the influence of a ...long-term, strictly GFD on their nutritional status and compared it with matched healthy volunteers.
Our study included 39 celiac patients and 39 healthy volunteers. The body mass index (BMI) of patients and controls was evaluated at enrollment, while the patients' BMI before the GFD was retrieved from clinical records. In addition, at enrollment, in both groups, we compared BMI, fat mass (FM), bone mineral density (BMD), as well as their dietary intake, recorded on a 7-day diary.
At the time of diagnosis, the majority of celiac patients (82.0%) had a normal BMI or were overweight, while 10.3% were malnourished. After the GFD, patients with a normal BMI showed a significant weight increase (P=0.002), but none of them switched in the overweight or obese category. Two (50%) of the four malnourished patients achieved a normal BMI. Controls and patients on a GFD had a similar BMI, FM, BMD and total calorie intake, but the amount of lipids and fiber intake was significantly different in the two groups (P=0.003 and P<0.0001, respectively).
Our study demonstrates that a GFD is able to improve the nutritional status of celiac patients without inducing overweight or obesity. Our findings are related to a celiac population adopting a GFD based on a Mediterranean-type diet.
Abstract
The dynamic atmosphere imposes challenges to ground-based cosmic microwave background observation, especially for measurements on large angular scales. The hydrometeors in the atmosphere, ...mostly in the form of clouds, scatter the ambient thermal radiation and are known to be the main linearly polarized source in the atmosphere. This scattering-induced polarization is significantly enhanced for ice clouds due to the alignment of ice crystals under gravity, which are also the most common clouds seen at the millimeter-astronomy sites at high altitudes. This work presents a multifrequency study of cloud polarization observed by the Cosmology Large Angular Scale Surveyor experiment on Cerro Toco in the Atacama Desert of northern Chile, from 2016–2022, at the frequency bands centered around 40, 90, 150, and 220 GHz. Using a machine-learning-assisted cloud classifier, we made connections between the transient polarized emission found in all four frequencies with the clouds imaged by monitoring cameras at the observing site. The polarization angles of the cloud events are found to be mostly 90° from the local meridian, which is consistent with the presence of horizontally aligned ice crystals. The 90 and 150 GHz polarization data are consistent with a power law with a spectral index of 3.90 ± 0.06, while an excess/deficit of polarization amplitude is found at 40/220 GHz compared with a Rayleigh scattering spectrum. These results are consistent with Rayleigh-scattering-dominated cloud polarization, with possible effects from supercooled water absorption and/or Mie scattering from a population of large cloud particles that contribute to the 220 GHz polarization.
We review the modeling progress of the magnetic response of hard type-II superconductors (SCs) using the critical-state model (CSM). We focus on magnetization loops when a uniform field is applied to ...the SC and on the levitation forces that appear when the applied field is nonuniform. Different analytical and numerical solutions of the CSM are discussed, and the main characteristics and parameters of the magnetization loops and levitation forces are reviewed. Although this paper does not pretend to be an exhaustive review of the modeling of type-II SCs or of the superconducting levitation studies, a general overview of some important theoretical models used to understand the hard type-II SC macroscopic behavior is presented.
•Ta introduction strongly decreases the 850 °C oxidation rate in TiAlN and TiAlYN.•Y introduction increases the room temperature hardness significantly in TiAlN and TiAlTaN.•Thicker oxide layer ...causes less wear in running-up stage of ball-on-disk wear test.
A comparative study of as-deposited structural properties, oxidation and wear properties of industrially arc-deposited Ti-Al-N, Ti-Al-Y-N, Ti-Al-Ta-N and Ti-Al-Ta-Y-N is presented. In the as-deposited coatings, Ta leads to more compressive stress while Y reduces the compressive stress but increases the nanohardness. The nanohardness of Ti-Al-Ta-Y-N is shown to be dominated by Y while its oxidation rate is dominated by Ta. Interestingly, Ta specifically favours the growth of oxide at the interface between Al-rich and Ti-rich oxide layers.In 850°C ball-on-disk wear tests, there is a pronounced effect of the running-in stage, which in turn depends strongly on the oxidation properties of the coating.The transferability of these findings to industrial machining at higher temperatures are discussed.
•Perturbation of water surface is explored to improve single-slope solar still production.•Air bubbles injection produces surface ripples increasing evaporative area.•The overall evaporative mass ...transfer coefficient is enhanced.•Experimental results show a yield increase of 12% in perturbed solar still.•Experimental results are processed in a mathematical model.
Solar still water production enhancement was measured in experimental single-slope basin-type solar stills (BTSS) by perturbing the water surface of the still. The perturbation is achieved by the injection of air bubbles into the water basin, which produces surface ripples, thus increasing the overall evaporative surface area and stimulating the mass transfer coefficient. Overall, distilled water production is therefore enhanced as the evaporation improves. The position and flowrate of the air bubble injectors do not seem to affect the amount of evaporation increase. Two very low-tilt covered, shallow BTSS were operated simultaneously side by side. Only one of them was subjected to mass transfer enhancement, in order to produce conclusive mass transfer enhancement results. These results can be accommodated in a computer simulation program with the introduction of a simple intensification factor. Experimental work was carried out in the semi-desert, water-starved, highly insolated region of La Paz, BCS, Mexico.
In this paper, we explore the power of the cosmic microwave background (CMB) polarization (E-mode) data to corroborate four potential anomalies in CMB temperature data: the lack of large ...angular-scale correlations, the alignment of the quadrupole and octupole (Q–O), the point-parity asymmetry, and the hemispherical power asymmetry. We use CMB simulations with noise representative of three experiments—the Planck satellite, the Cosmology Large Angular Scale Surveyor (CLASS), and the LiteBIRD satellite—to test how current and future data constrain the anomalies. We find the correlation coefficients ρ between temperature and E-mode estimators to be less than 0.1, except for the point-parity asymmetry (ρ = 0.17 for cosmic-variance-limited simulations), confirming that E-modes provide a check on the anomalies that is largely independent of temperature data. Compared to Planck component-separated CMB data (smica), the putative LiteBIRD survey would reduce errors on E-mode anomaly estimators by factors of ∼3 for hemispherical power asymmetry and point-parity asymmetry, and by ∼26 for lack of large-scale correlation. The improvement in Q–O alignment is not obvious due to large cosmic variance, but we found the ability to pin down the estimator value will be improved by a factor ≳100. Improvements with CLASS are intermediate to these.
Abstract
The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background over 75% of the sky from the Atacama Desert, Chile, at frequency bands ...centered near 40, 90, 150, and 220 GHz. This paper describes the CLASS data pipeline and maps for 40 GHz observations conducted from 2016 August to 2022 May. We demonstrate how well the CLASS survey strategy, with rapid (∼10 Hz) front-end modulation, recovers the large-scale Galactic polarization signal from the ground: the mapping transfer function recovers ∼67% (85%) of
EE
and
BB
(
VV
) power at
ℓ
= 20 and ∼35% (47%) at
ℓ
= 10. We present linear and circular polarization maps over 75% of the sky. Simulations based on the data imply the maps have a white noise level of
110
μ
K
arcmin
and correlated noise component rising at low-
ℓ
as
ℓ
−2.4
. The transfer-function-corrected low-
ℓ
component is comparable to the white noise at the angular knee frequencies of
ℓ
≈ 18 (linear polarization) and
ℓ
≈ 12 (circular polarization). Finally, we present simulations of the level at which expected sources of systematic error bias the measurements, finding subpercent bias for the Λ cold dark matter
EE
power spectra. Bias from
E
-to-
B
leakage due to the data reduction pipeline and polarization angle uncertainty approaches the expected level for an
r
= 0.01
BB
power spectrum. Improvements to the instrument calibration and the data pipeline will decrease this bias.
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