Miracle-dz/UniFAR-FTUs huggingface dataset:
Hydrogen bonds, water rotation and proton mobility

La mobilite du proton est traditionnellement concue comme etant gouvernee par les rotations des molecules d'eau. Les temps de rotation dans l'eau lourde, obtenus des mesures RMN de relaxation spin-reseau, sont compares avec les temps de saut du proton, avec et sans soustraction de la mobilite hydrodynamique estimee. Dans ce dernier cas, les deux donnees s'accordent bien, a haute temperature. On en conclut que la mobilite hydrodynamique du proton est considerablement plus basse que celle qui avait ete admise jusqu'a present, car H 3 O + est presque immobilise par des liaisons hydrogene extremement fortes. Ces dernieres liaisons, provenant de la premiere sphere d'hydratation, sont environ 2 kcal/mole plus fortes que les liaisons hydrogene de l'eau pure. Dans l'eau en dessous de 20°C, la rotation des molecules est plus lente que le saut de proton, et son energie d'activation comporte une composante hydrodynamique. Par consequent, la mobilite du proton n'est pas gouvernee par la rotation des molecules d'eau, mais ces deux processus sont limites par la dynamique des liaisons hydrogene. Une comparaison avec les temps de vie des liaisons hydrogene, mesures par diffusion de lumiere depolarisee, suggere que deux brisures consecutives de liaisons hydrogene ordinaires, constituent un seul saut de proton. Ceci est en accord, avec un modele recent concernant le mecanisme de Grotthuss.
A Grand-Potential Based Phase-Field Approach for Simulating Growth of Intermetallic Phases in Multicomponent Alloy Systems

Abstract Intermetallic phase-based alloys, in particular transition-metal aluminides, are potential structural and coating materials for high-temperature applications. Such applications usually involve interdiffusion between two dissimilar materials. To simulate interdiffusion microstructures quantitatively, it becomes essential to solve alloy phase-field models in conjunction with multicomponent CALPHAD databases. This coupling, however, still remains a challenge when considering binary or multicomponent intermetallic phases. Here, a novel method that incorporates successfully diffusion potential dependent-properties of bulk multicomponent phases into a grand-potential based multi-phase-field model is proposed. It uses phase-specific properties directly precomputed from CALPHAD-type databases as discrete functions of solute diffusion potentials. Six different alloy cases, ranging from a five-phase binary (Ni-Al) to a two-phase quaternary (Al-Cr-Ni-Fe) alloy, are simulated to illustrate the application and correctness of the method. The cases include both substitutional and intermetallic phases. Where a comparison is possible, the simulations show good agreement with DICTRA and experimental results, thus validating our proposed method. In contrast to our approach, we find that DICTRA fails in three of the simulations involving ordered intermetallics. We further show that the interface width in this model can be varied without accuracy loss, thus enabling computationally affordable simulations at experimentally comparable length and time scales.
Mechanical properties and failure mechanisms of 3D-printed PLA scaffolds: A preliminary study

Polylactic acid (PLA) porous composite scaffolds with three different infill patterns were subjected to compression testing. The composites were fabricated by 3D printing based on Fused Filament Fabrication (FFF) technology. Stress-strain curves were obtained which allowed to identify Young’s modulus, yield point and residual strain of samples. 3D tomography images were taken before and after deformation. Comparison between images corresponding to a particular sample were used to identify deformation and failure mechanisms.
Estimation of soil properties with mid-infrared soil spectroscopy
across yam production landscapes in West Africa

Abstract. Low soil fertility is challenging the sustainable production of staple crops in the yam belt of West Africa. Quantitative soil measures are needed to assess soil fertility decline and to improve crop fertilization management in the region. We developed and tested a mid-infrared (mid-IR) soil spectral library to enable timely and cost-efficient assessments of soil properties. Our collection included 80 soil samples from four landscapes (10 km × 10 km) and 20 fields/landscape across a gradient from humid forest to savanna, and 14 additional samples from one landscape that had been sampled within the Land Health Degradation Framework. We derived partial least square regression models to estimate soil properties with spectra.The models produced accurate cross-validated estimates of total carbon, total nitrogen, total sulfur, total iron, total aluminum, total potassium, total calcium, exchangeable calcium, effective cation exchange capacity, diethylenetriaminepentaacetic acid (DTPA) extractable iron and clay content (R2 > 0.75). The estimates of total zinc, pH, exchangeable magnesium, bioavailable copper and manganese were less predictable (R2 > 0.50). Our results confirm that mid-IR spectroscopy is a reliable and quick method assess the regional-scale variation in most soil properties, especially the ones closely associated with soil organic matter. Although the relatively small mid-IR library shows satisfactory performance, we expect that frequent but small model updates will be needed to adapt the library to the variation of soil quality attributes within individual fields in the regions and their temporal fluctuations.
The potential for digital technology to support self-directed learning in formal education of children: a scoping review

ABSTRACT Self-directed learning is a critical competence for living and working in our increasingly complex and unpredictable world. The concept of self-directed learning grew out of the adult learning field and scholars highlight the need to examine how self-directed learning competence can be fostered during childhood. However, there are very few empirical studies that seek to understand how self-directed learning is facilitated in the formal education of children in our digital age. In order to review empirical studies that contribute toward understanding this research question, a literature search was conducted. The potential for digital technology to support learners in this process was highlighted in the studies reviewed, but commonly learners lacked the competence to use digital technologies for educational purposes. Learners often required support, especially with the planning and reviewing aspects of self-directed learning, as well as guidance regarding how digital technologies can be used effectively for educational purposes. Importantly, studies that focus on understanding the facilitation of self-directed learning in childhood education are seldom. Further studies on self-directed learning in childhood education are vital – given that this is a fundamental competence for preparing our youth to deal with work and life in our rapidly changing world.
Short-Term Effects of Fire Severity on Vegetation Based on Sentinel-2 Satellite Data

An important component in improving the quality of forests is to study the interference intensity of forest fires, in order to describe the intensity of the forest fire and the vegetation recovery, and to improve the monitoring ability of the dynamic change of the forest. Using a forest fire event in Bilahe, Inner Monglia in 2017 as a case study, this study extracted the burned area based on the BAIS2 index of Sentinel-2 data for 2016–2018. The leaf area index (LAI) and fractional vegetation cover (FVC), which are more suitable for monitoring vegetation dynamic changes of a burned area, were calculated by comparing the biophysical and spectral indices. The results showed that patterns of change of LAI and FVC of various land cover types were similar post-fire. The LAI and FVC of forest and grassland were high during the pre-fire and post-fire years. During the fire year, from the fire month (May) through the next 4 months (September), the order of areas of different fire severity in terms of values of LAI and FVC was: low > moderate > high severity. During the post fire year, LAI and FVC increased rapidly in areas of different fire severity, and the ranking of areas of different fire severity in terms of values LAI and FVC was consistent with the trend observed during the pre-fire year. The results of this study can improve the understanding of the mechanisms involved in post-fire vegetation change. By using quantitative inversion, the health trajectory of the ecosystem can be rapidly determined, and therefore this method can play an irreplaceable role in the realization of sustainable development in the study area. Therefore, it is of great scientific significance to quantitatively retrieve vegetation variables by remote sensing.
EVALUATION OF ANTIOXIDANT EFFECT OF ALCOHOLIC ROOTS EXTRACT OF EUPHORBIA HIRTA LINN. – IN VITRO

Objective: The main objective of the present study was to undergo an investigation on free radical scavenging activity of the roots of Euphorbia hirta Linn. and was compared with a standard antioxidant compound like ascorbic acid. Methods: Euphorbia hirta roots extract was tested for total flavonoid content, total phenolic content, and in vitro antioxidant activity by 1, 1-diphenyl- 2-picrylhydrazyl (DPPH) free radical scavenging assay (DPPH) assay, superoxide anion radical scavenging assay, and nitric oxide scavenging assay. Results: The alcoholic roots extract of E. hirta was screened for free radical scavenging and antioxidant activities using three different methods. It was found that percentage inhibition of the extract was concentration-dependent. Total phenolic content and total flavonoid content were found to be 265.72±1.3 and 45.67±1.14, respectively. The alcoholic extract of E. hirta produced a dose-dependent inhibition of superoxide radicals ranging from 40.14±0.14 to 70.93±0.10. The mean IC50 values for DPPH radical by root extract of E. hirta and ascorbic acid were found to be 18.12 μg/ml and 13.17 μg/ ml, respectively. The alcoholic extract of E. hirta produced dose-dependent inhibition of nitric oxide radicals scavenging effect ranging from 17.05±0.18 to 51.08±0.30. The alcoholic extract of E. hirta and ascorbic acid shows mean IC50 values for superoxide radical as 23.64 μg/ml and 14.36 μg/ml, respectively. Conclusions: The present study showed that E. hirta possesses a considerable amount of both phenolic and flavonoid content. The alcoholic root extract also shows good antioxidant potential. The results of the present study also encourage for further in vivo studies and isolation and characterization of active compounds.
Unequal but Fair: Incorporating Distributive Justice in Operational Allocation Models

Fairness is a natural concern when model‐based decisions affect human beings. In personnel‐management decisions, employees’ perceptions of fairness depend both upon the decision processes as well as the resulting outcomes. Acting as a key part of decision processes, operational models often emphasize equality, or sameness, of outcomes among individuals. Fair outcomes, as a manifestation of distributive justice, involve balancing two competing aspects: equality and equity. Equity, in opposition to equality, is concerned with an individual’s outcomes being commensurate with their inputs. While both aspects of distributive justice can be an expectation of members of an organization, they present an inherent trade‐off; more of one requires less of the other. In order to balance the trade‐off between equity and equality, we propose a bi‐objective, non‐linear optimization model, which is then extended to a mixed‐integer formulation in a service‐oriented case study. Specifically, the case study model allocates physicians’ contracted clinical time across multiple emergency department locations. Deviations from physicians’ equity‐weighted preferences for where they work are minimized and a Pareto frontier of objectively fair solutions is derived. As a result, the time physicians were allocated to locations they did not prefer was substantially reduced. In addition, pre‐ and post‐implementation surveys revealed statistically significant improvements in employee reported perceptions of fairness, transparency, and overall satisfaction with the work‐time‐allocation process. The evidence supports the conclusion that decision models designed to result in unequal outcomes can still be perceived as fair by the employees they affect.
Color Modulates the Timing of Conscious Perception via Bottom-Up and Top-Down Attention

Color can direct visual attention to specific locations through bottom-up and top-down 1 mechanisms. Using Continuous Flash Suppression (CFS) as way to investigate the factors that 2 gate access to consciousness, the current study investigated whether color also directly affected 3 the timing of conscious perception. Low or high spatial frequency (SF) gratings with different 4 orientations were shown as targets to the non-dominant eye of human participants. CFS patterns 5 were presented at a rate of 10Hz to the dominant eye to delay conscious perception of the targets, 6 and participants had the task to report the target’s orientation as soon as they could see it. With 7 low-SF targets, two types of color-based effects became evident. First, when the targets and the 8 CFS patterns had different colors, the targets entered consciousness faster than in trials where the 9 targets and CFS patterns had the same color. Second, when participants searched for a specific 10 target color, targets that matched these search settings entered consciousness faster compared 11 to conditions where the target color was irrelevant and could vary from trial to trial. Thus, the 12 current study demonstrates that color is a central feature of human perception and leads to faster 13 conscious perception of visual stimuli through bottom-up and top-down attentional mechanisms. 14
Hybrid Analytical Modeling of Air-Gap Magnetic Field in Asymmetric-Stator-Pole Flux Reversal Permanent Magnet Machine Considering Slotting Effect

This article proposes an accurate and computationally efficient hybrid analytical (HA) model for the air-gap magnetic field computation of asymmetric-stator-pole flux reversal permanent magnet machine, which can provide a thorough insight into the working mechanism by taking the slotting effects into account. The proposed HA model combines the subdomain method and Schwarz–Christoffel (SC) transformation, which can account for the stator and rotor slotting effects, respectively. The subdomain method is first employed to predict the air-gap magnetic field considering the rotor slotting effect by converting the machine geometry to a slotless stator model. Afterward, a complex relative permeance function is obtained by the SC transformation, in which the stator slotting effect is taken into account. Finally, the complete air-gap magnetic field distribution of the machine can be efficiently predicted by the proposed HA analytical model. The effectiveness of the proposed HA model is verified by both finite-element analyses and experimental results.
Effect Of Carbon Black Loading On Linear Low-Density Polyethylene Properties

The mechanical, thermal, electrical, reheology, and morphological properties of composites made from linear low-density polyethylene and carbon black (CB) content of 5%, 10%, and 20% by weight were investigated. The optimum mechanical and electrical properties performance was achieved with the adding of 5% carbon black. The drop in properties after adding more CB is due to agglomeration and poor dispersion of carbon particles in the polymer matrix. CB resulted in higher dynamic viscosity and storage modulus at low frequencies, although this phenomenon was reversed at high frequencies. CB resulted in more shear thinning of LLDPE at high shear rates.
Keeping the Dream Alive: Is Propellant-less Propulsion Possible?

“Breakthrough” advanced propulsion can only take place with a correct understanding of the role of inertia in general relativity. Einstein was convinced that inertia and gravitation were the obverse and reverse of the coin. The most general statement of the principle of relativity, captured in his Equivalence Principle and the gravitational induction of inertia. His ideas and how they have fared are reprised. A rest mass fluctuation that is expected when inertia is gravitationally induced is then mentioned that can be used for propulsion. Recent work supported by National Innovative Advanced Concepts Phase 1 and 2 NASA grants to determine whether thrusters based on gravitationally induced inertia can actually be made to work is presented. A recent design innovation has dramatically increased the thrust produced by these Mach Effect Gravity Assist (MEGA) impulse engines.
NB-IoT Random Access: Data-Driven Analysis and ML-Based Enhancements

In the context of massive machine-type communications (mMTCs), the narrowband Internet-of-Things (NB-IoT) technology is envisioned to efficiently and reliably deal with massive device connectivity. Hence, it relies on a tailored random access (RA) procedure, for which theoretical and empirical analyses are needed for a better understanding and further improvements. This article presents the first data-driven analysis of NB-IoT RA, exploiting a large-scale measurement campaign. We show how the RA procedure and performance are affected by network deployment, radio coverage, and operators' configurations, thus complementing simulation-based investigations, mostly focused on massive connectivity aspects. A comparison with the performance requirements reveals the need for procedure enhancements. Hence, we propose a machine learning (ML) approach and show that RA outcomes are predictable with good accuracy by observing radio conditions. We embed the outcome prediction in an RA-enhanced scheme and show that optimized configurations enable power consumption reduction of at least 50%. We also make our data set available for further exploration, toward the discovery of new insights and research perspectives.
Fast and robust fringe projection profilometry for surface with hole discontinuities via backlighting

In fringe projection profilometry (FPP), objects with hole discontinuities can lead to shadows and even phase unwrapping morbidity. To solve this problem, we propose an enhanced FPP system by employing the backlighting technique in this paper. This method consists of shadow compensation (SC) and high dynamic range (HDR) imaging; the SC is implemented using the optimal mask, which is obtained by fusing two high-contrast images from different backlight intensities; the HDR imaging is performed by a multi-exposure technique to tackle the issue of multi-colored or specular reflections. Since the proposed method does not require complex phase-unwrapping algorithms, it is fast and robust for three-dimensional shape measurement of objects with hole discontinuities. To validate the method, morphological measurements of a wheel rim and a multi-colored human mask were performed. The results show that the proposed method can overcome discontinuity problems without degrading performance.
Volatile organic compound fluxes over a winter wheat field by
PTR-Qi-TOF-MS and eddy covariance

Abstract. Volatile organic compounds (VOC) contribute to air pollution through the formation of secondary aerosols and ozone and contribute to increasing the lifetime of methane in the atmosphere. Tropospheric VOC are 90 % originating from biogenic sources at the global scale. Forests are the main contributors to these emissions with isoprene and monoterpenes being the most emitted compounds. Crops are also a potentially large, yet poorly characterised, source of VOC. In particular, measurements of VOC fluxes for wheat at the ecosystem scale are scarce, although this is the most cultivated crop in Europe. Available evidence indicates that crops may contribute to 30% of the VOC emissions in Europe, especially oxygenated, low-molecular-weight VOC such as methanol, acetone and acetaldehyde. In this study, which is part of the COV3ER French national project, we investigated VOC fluxes over a wheat field in-situ by eddy covariance using a PTR-Qi-TOF-MS with an outmost sensitivity and mass resolution. We found 264 compounds to have a flux three times above the flux detection limit. Methanol was the most emitted compound, with an averaged flux of 63 µg m−2 h−1, representing around 60 % of summed VOC emissions on a molar basis (40 % on a mass basis). This finding is in line with previous measurements at canopy and plant scales. We also measured acetone, acetaldehyde and dimethyl sulphide among the five most emitted compounds. The second most emitted VOC corresponded to the ion m/z 93.037, tentatively identified as C6H4O. This compound was not reported previously as one of the most emitted compound by terrestrial ecosystems. Summed VOC emissions amounted around 150 µg m−2 h−1. Summed VOC deposition amounted to around −125 µg m−2 h−1, which represented about 70 % of the VOC emissions on a mass basis. The most depositing VOC were tentatively identified as hydroxyacetone and fragments of oxidised VOC with a flux of −16 µg m−2 h−1. Overall, our results reveal that wheat fields represent a non-negligible source and sink of VOC to be considered in regional VOC budgets, and underline the usefulness and limitations of eddy covariance measurements with PTR-Qi-TOF-MS.
Scale‐dependent effects of environmental factors on soil organic carbon, soil nutrients and stoichiometry under two contrasting land‐use types

Variations in and control of soil total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) and their stoichiometric ratios (C:N, C:P and N:P) are critical in agricultural nutrient management. This study examined the scale‐dependent effects of environmental factors on these soil properties under two contrasting land‐use types (tea versus. bamboo) at plot scale (70 × 70 m) and landscape scale (2 × 2 km). Results showed that at both scales, the tea garden generally had higher TOC and nutrient concentrations and lower stoichiometric ratios than the bamboo forest, because of fertilizer and green manure applications in the tea garden. Influences of topography and soil texture on TOC, nutrients and stoichiometric ratios were scale‐dependent. In the tea garden plot, as scale increased, influences of topography and soil texture on TOC, TN and C:N ratio increased, whereas their influence on TP, C:P ratio and N:P ratio decreased. Similar patterns were observed in the forest plot. At the landscape scale, the effects of influences of topography and soil texture on TOC and nutrients were not obvious. The spatial variations in TOC, nutrients and stoichiometric ratios were controlled by both topography and soil texture at the plot scale but were mainly influenced by soil texture at the landscape scale. The influences of topography and soil texture on TOC, nutrients and stoichiometric ratios were generally weaker at landscape than at plot scale. This study confirmed that the effect of scale must be considered when predicting the spatial variations in TOC and nutrients.