Miracle-dz/UniFAR-FTUs huggingface dataset:
Growth mechanism of superconducting MgB_2 films prepared by various methods

The growth mechanisms of MgB_2 films obtained by different methods on various substrates are comparably studied by transport measurements and scanning electron microscopy observations. The analyzed films include those prepared by ex situ postanneal with T _c0 ˜38.8 K and those from in situ anneal with T _c0 ˜24 K. It is clearly observed that the films obtained by the high-temperature reaction of e-beam evaporated B with Mg vapor are formed by the nucleation of independent MgB_2 grains at the film surface, indicating that this approach may not be suitable to obtain epitaxial films. A significant oxygen contamination was also present in films obtained from pulsed-laser-deposition-grown precursors, which drag the T _c0 down to 24 K.
Synthesis of Water‐Soluble Coprecipitated CdxZn(1−x)S Nanoparticles

Coprecipitated CdxZn(1−x)S nanoparticles have been synthesized using the chemical capping method. Mercaptoacetic acid was used as an efficient and versatile capping agent, that can provide the nanoparticles with a hydrophilic shell and prevent their coalescence. Optical spectroscopy provided evidence that the particles were coprecipitated, and the absorption edges of those nanoparticles can be varied from blue to UV, while the emission position can be adjusted from 450 to 670 nm.
Robust Offloading Scheduling for Mobile Edge Computing

In this paper, we study the problem of Robust offloading schEduling for mobIle edge computiNg (REIN), i.e., in the presence of uncertain offloading failures, how to determine an offloading schedule to minimize the overall latency of all computation-intensive tasks. We mathematically formulate the problem in the form of min-max robust optimization, based on the twice equivalent transformations of the scheduling problem that originally does not consider robustness. REIN is challenging to solve because the min-max robust objective is computationally intractable with existing approaches, and the monotonicity of the objective function is uncertain, even if we transform the objective into the popular max-min form by introducing an appropriate constant upper bound. To solve the above challenges, we first construct a constant upper bound and a monotone modular function to approximate the transformed max-min objective function, and then propose a computationally feasible solution with provable performance bound. Moreover, given the fact of the weak computation ability of users in practical, we construct a tighter constant upper bound and a monotone submodular approximation function, and propose a feasible solution with possibly improved performance bound. Extensive results show that, given a maximum number of offloading failures, our proposed algorithms outperform three benchmark algorithms, and approach the optimum at small time costs.
Influence of the Rest Period on the Charge Released by a Lead Acid Battery

This paper presents the characteristics of a lead acid battery regarding the charge that it can release. It is desired to determine the effect of the rest period on the charge released by the battery. For this purpose a series of experiments that contain at least one rest period are presented. In each of them the charge released is counted, depending on the time when the rest period is started. It is pointed out that, every battery can release a charge equal with its rated capacity if the discharge contains rest periods.
Modification of the Mehlich Lime Buffer Test

Routine use of the Shoemaker, McLean, and Pratt (SMP) lime buffer method resulted in chronic problems with electrode reference junction degradation, stability of readings relative to contact time, and generation of hazardous waste. During method recalibration, the Mehlich buffer was chosen for parallel evaluation with SMP, with the goal of improving method performance and eliminating of hazardous waste. The Mehlich buffer was modified by substituting calcium (Ca) for barium (Ba). The modified Mehlich (MM) buffer was found to be identical to the original with respect to buffering power and linearity over an extended pH range of 3.0–6.6. Seven agronomic soils were incubated with eight rates of calcium carbonate for 90 days. Regression analysis was performed to predict lime requirement (LR) to several target pH levels, based on pH measured in each buffer alone or in both water and buffer. Slightly better predictability was obtained using multiple regressions, with R2>0.95 in all cases. Significant but minor differences occurred between the newly calibrated buffers in extended comparisons. The MM buffer was superior to the SMP during routine usage, with fewer adverse effects on electrodes and the elimination of hazardous waste.
Molecular imprinting in thin films of organic-inorganic hybrid sol-gel and acrylic polymers

The molecular imprinting technique was applied on a model compound, propranolol, using two polymeric systems, acrylic and hybrid organic−inorganic sol−gels. The polymers were applied as thin films on glass substrates. The preparation of thin films of imprinted acrylic polymers required the development of a new polymerization system. The binding properties of the two polymers toward propranolol were characterized by radioactive and fluorimetric assay procedures. The acrylic system was found to have high uptake toward propranolol, but this was accompanied by a high degree of nonspecific binding. The sol−gel system had lower uptake, but remarkably lower nonspecific binding (<10%). The Kd of the sol−gel matrix to propranolol is 80 ± 6 nM, a value that is common in biological systems. The binding was found to be solvent sensitivewith high affinity and specificity in aqueous solution, which was completely lost in organic solvents. The uptake kinetics of the acrylic polymer was significantly slower than the sol−.
Growth properties of sulfide trees in cables under dc stress

Investigations on the growth properties of sulfide tree in cable insulation, subjected to dc electric fields, are described in this paper. Measurements of electric strength and conductivity are correlated to tree growth, observed by optical and electron microscopy, during accelerated aging tests performed in sea water with hydrogen sulfide. It is shown that both electric strength and dc conductivity are very sensitive to the length and concentration of sulfide trees, and that the magnitude of the electric field affects tree shape and growth rate significantly.
Oxidation of alkoxyphenols. Part X. The reaction of 2,2′-dihydroxy-5,5′-dimethoxy-3,3′-di-t-butylbiphenyl with lead tetra-acetate

Oxidation in acid solution converts 2,2′-dihydroxy-5,5′-dimethoxy-3,3′-di-t-butylbiphenyl into 3,3′-di-t-butyl-biphenyl-2,5:2′,5′-diquinone, and in benzene into 6a-acetoxy-4,6a-dihydro-5′-methoxy-4-oxo-3′,6-di-t-butyl-benzoxet-2-spiro-1′-cyclohexa-3′,5′-dien-2′-one. The latter's structure is shown by reductive acetylation to a tetra-acetoxy- and a diacetoxy-biphenyl and an acetoxydibenzofuran. The oxidation proceeds through 4,5′-dimethoxy-3′,6-di-t-butylbenzoxet-2-spiro-1′-cyclohexa-3′,5′-dien-2′-one. The reductive acetylation, Thiele acetylation, and reaction with alcohols of this intermediate are also examined.
Ultrafast x‐ray absorption probing of a chemical reaction

Ultrafast x‐ray techniques can, in principle, allow us to more directly watch the time evolution of matter, with atomic spatial resolution and with time resolution on the scale of atomic motions such as the making and breaking of chemical bonds, in order to more directly observe the fundamental molecular dynamics underlying the concept of ‘‘mechanism’’ in inorganic, organic, and biochemical reactions. As a step toward this goal, we have observed a chemical reaction process, photoinduced dissociation of gas phase SF6 molecules, detected by ultrafast near‐edge x‐ray absorption spectroscopy with time resolutions of 1.5–3 ps, near the sulfur K edge at a photon energy of 2.48 keV (4.98 A).
The heterogenization of homogeneous metallocene catalysts for olefin polymerization

Metallocene complexes of titanium, zirconium and hafnium are very active and versatile catalysts for olefin polymerization and are already contributing to commercial production. Owing to a variety of catalyst parameters a wide range of polymers with various properties are accessible. Since metallocene complexes are homogeneous in solution they can easily be studied by spectroscopic methods. However, for industrial application they must be heterogenized.
Hydrochemical Characterization of Aquifers Using Sequential Multivariate Analyses and Geographic Information Systems in a Tropical Setting

This study demonstrates yet another innovation in the application of multivariate analysis to the understanding of regional hydrochemical processes in a tropical setting. Sequential Q-mode hierarchical cluster analysis (HCA) and factor analysis were used jointly with geographic information systems (GIS) and conventional graphical methods to determine spatial groundwater types in Ghana, and the spatial variation of the major sources of hydrochemical change in groundwater in Ghana. This study finds that two major groundwater types exist in the country: the Na-Cl groundwater types, which dominate the coastal aquifers where groundwater salinity is high, and Na-K-HCO3 groundwater types, which dominate aquifers farther inland. The major source of variation in hydrochemistry of groundwater in Ghana is mineral weathering and saline water intrusion. Silicate mineral weathering has strong effects in the more inland aquifers whereas saline water intrusion has the greatest effects along the coast. Chemical fertilizer.
Alternatives to formic acid as a grass silage additive under two contrasting ensilability conditions

The effects of formic acid and four alternative additives on silage fermentation, in-silo DM losses and aerobic stability were compared in an experiment using both difficultto-ensile (DIFF) and easier-to-ensile (EASI) herbages. Both were ensiled in laboratory silos with either no additive or following the application of formic acid (FA; 850 g/kg) at 3 mL/kg herbage, Add-SaFeR ® (ATF1) and GrasAAT ® (ATF2), both based on ammonium tetraformate, at 4 mL/kg herbage, an antimicrobial mixture (MIX; potassium formate, sodium disulfite and sodium benzoate) at 3 g/kg herbage, or Ecosyl (LAB; Lactobacillus plantarum) at 3 mL/kg herbage. There were four replicates per treatment and the silos were stored for 132 days. DIFF silage made without additive was poorly fermented. All additives increased the extent and improved the direction of DIFF silage fermentation, and reduced in-silo losses. However, MIX did not reduce butyric acid concentration and increased the extent of aerobic deterioration. LAB had a smaller effect on fermentation and in-silo losses than FA. With EASI silages, all additives restricted the extent of fermentation and improved fermentation quality, with the latter effect being smaller than for DIFF silages. LAB promoted a particularly homolactic fermentation but subsequently increased aerobic deterioration. In both DIFF and EASI silages additive treatment improved in vitro digestibility. It is concluded that only ATF1, ATF2 and MIX were as effective as FA at improving silage preservation and reducing in-silo losses with both DIFF and EASI herbages. However, ATF1 and ATF2 were superior in reducing the apparent extent of proteolysis and MIX was slightly less effective at reducing the activity of saccharolytic Clostridia.
Monodisperse SiC/vinyl ester nanocomposites: Dispersant formulation, synthesis, and characterization

A novel dispersant “mono-2-(methacryloyloxy)ethyl succinate” was formulated for dispersing 30-nm SiC nanoparticles in vinyl ester resin. The eight carbon rule was used as the guideline to achieve a particle–particle separation of 20 to 60 nm for colloid stability. Fourier transform infrared spectroscopy was performed to characterize the SiC particle surfaces. Only a negligible amount of oxidized layer was observed; which illustrates that the SiC surface is basic. Thus, the Lewis base-Lewis acid reactions make the functional group–COOH an effective adsorbate to the SiC nanoparticle surface. The organofunctional group “methacrylates,” which exhibits the best wet strength with polyester copolymerizes with styrene monomers in the vinyl ester during cure. Hence, this novel dispersant also acts as an efficient coupling agent that reacts with both SiC and vinyl ester. The monolayer coverage dosage of 62 fractional wt% of the dispersant was used to attain the minimum filled resin viscosity. The multicomponent compositional imaging using atomic force microscopy confirmed the monodisperse SiC nanoparticles in vinyl ester. The 3 vol% SiC reinforced vinyl ester achieved a 75% increase in modulus, 42% increase in strength, and 75% increase in toughness as compared with the neat resin without nanofiller reinforcement.
Cluster-Based Modeling of Fluidized Catalytic Oxidation of n-Butane to Maleic Anhydride

A mathematical model is proposed for the partial oxidation on n-butane to maleic anhydride (MAN) in a gas-solid fluidized bed reactor. The reactor consists of two regions, i.e., a lower dense region and an upper dilute region. The dynamic two-phase structure was used for modeling the lower dense bed hydrodynamics. The upper region hydrodynamics was modeled by a cluster based approach. This allows the porosity distribution to be calculated for plug flow reactor model assumed for the gas phase in this region. The basic assumption in the cluster based approach is that the solid particles move only as clusters and the amount of single particles in the upper region is negligible. The mathematical model was obtained from coupling the kinetic sub-model, obtained from the literature, with this hydrodynamics sub-model. Comparing the results of the model with the experimental data available in the literature showed close agreement. Two other methods (i.e., particle based approach and short-cut) were also tested in this work. However, it was found that the cluster based approach modeling is quite suitable for the fluidized bed reactor used in this study. The short-cut method seems reasonably applicable for the prediction of the overall conversion but does not provide any local information (such as concentration profiles, yield, etc.) within the fluidized bed reactor.
Effect of crosslinkers on photocopolymerization of N-vinylpyrrolidone and methacrylates to give hydrogels

N-Vinylpyrrolidone (NVP) and methacrylates are frequently copolymerized to give hydrogels useful as contact lenses. However, the nature of their copolymerization was not well understood. In this study, the effect of a crosslinker on the photocopolymerization of NVP and 2-hydroxyethyl methacrylate (HEMA) was discussed. It was found that crosslinkers with a vinyl carbonate group can copolymerize with NVP better than those containing an allyl group, which, in turn, are better than those containing a methacrylate group. A crosslinker with a vinyl carbonate and a methacrylate group can copolymerize NVP and HEMA the best in terms of giving hydrogels with the highest water content, followed by a crosslinker with a combination of allyl and methacrylate groups. Crosslinkers with only methacrylate or vinyl carbonate groups gave hydrogels either too fragile or too stiff to be useful. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1475–1484, 1997
Determination of Polyaromatic Hydrocarbons in Atmospheric Particulate Samples by HPLC with Fluorescence Detection: A Field Application

Abstract The content of polycyclic aromatic hydrocarbons (PAHs) was monitored in atmospheric particulate matter collected at two highway toll stations in Italy during both winter- and summertime. In particular, the highest concentrations of both total PAHs (28.1 ng/m3) and benzo[a]pyrene (BaP) (5.0 ng/m3) were found outside the cabin at the Viareggio sampling station during wintertime; the lowest concentrations, 2.0 and 0.2 ng/m3, respectively, were observed outside the cabins during summertime, without significant differences between the two sampling stations. The profile of PAH distribution was the same for the samples collected in winter and summer, and the total PAH and BaP concentrations of each sample reflected the traffic load at the two toll stations. This may mean that the presence of PAHs in the areas studied is due mainly to emissions from motor vehicles.
Gas influence on the arc shape in MIG-MAG welding

Composition of the applied shielding gas has a strong influence on physical properties of the plasma and parameters of the welding process. In particular, increase of the percentage of carbon dioxide in argon results in an increase of the transition current value while changing from the globular to spray mode of metal transfer during the welding process. In order to explain this phenomenon, the MIG/MAG welding arc plasma was investigated for different mixtures of argon and carbon dioxide in the shielding gas. Applying a fast camera, recording distribution of spectral lines of the plasma components, we noticed some phenomena not described yet in the literature. Especially, there is a limit in the percentage of relative concentration CO 2 /Ar beyond which the arc shape is significantly modified.
ROTATIONAL ALIGNMENT OF PRODUCT MOLECULES FROM THE REACTION Ca + HCl→CaCl + H

The product rotational polarization in the Ca + HCl→CaCl + H reaction at collision energy of 20 kcal/mol has been studied via the quasiclassical trajectory method on a new ab initio potential surface. The P(θr) distribution of angle between k and j′, and the dihedral angular distribution P(Φr) characterizing k - k′ - j′ correlation are discussed, the angle distribution P(θr, Φr) of product rotational vectors in the form of polar plot in θr and Φr are shown. Furthermore, four PDDCSs (2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt) and (2π/σ)(dσ21-/dωt) are also presented. The present calculations reveal that the product rotational alignment is very strong. Finally, the state distributions of the product CaCl are investigated. The results showed that the CaCl product was formed with high vibrational and rotational excitation.
Mechanosensitive peptide gelation: mode of agitation controls mechanical properties and nano-scale morphology

In this study we demonstrate the sensitivity of fibrillar self-assembly and gelation of aromatic peptide amphiphiles to different modes of mechanical agitation. In particular, we show how different homogenization techniques (vortex vs. manual or orbital agitation) during the gelation process can dramatically influence the mechanical properties and the nano-scale organization of self-assembled materials. The pH-induced self-assembly of mixtures of fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) and Fmoc-diglycine (Fmoc-GG) to gel phase materials was performed under different agitation conditions (vortex vs. manual or orbital agitation). We demonstrate that mechanically induced differences of up to one order of magnitude in shear modulus could be obtained for chemically identical samples as measured using oscillatory rheology and in creep and recovery experiments. AFM imaging and nanoindentation were then employed to highlight morphological, mechanical and physico-chemical differences in the fibrillar elements (ribbons). Furthermore, we have demonstrated that although Fmoc-diglycine alone does not undergo fibrillar aggregation, nor is capable of gelation at neutral pH, its presence influences the properties of gels at both fibrillar and macroscopic level; in particular, a Fmoc-diglycine/Fmoc-diphenylalanine 1 : 1 molar ratio appeared to provide the highest moduli and the most regular fibers, suggesting a specific mode of intercalation of Fmoc-diglycine in Fmoc-diphenylalanine fibrils.
Powder X-ray diffraction study of synthetic PdSn

Improved X-ray powder diffraction data for synthetic PdSn are reported. Powder diffraction data were collected with a laboratory X-ray source (CuKα) for Rietveld refinement. Refined crystallographic data for PdSn (orthorhombic, Pnma) are a=6.1388(4), b=3.89226(3), c=6.3377(4) Å, V=151.43(2) Å3, Z=4, and Dx=9.87 g∕cm3.
Dynamics of entangled polymer melts: A computer simulation

As a model for dense polymer solutions or melts we consider an ensemble of n freely jointed chains consisting of N rigid links in a box. A Lennard‐Jones interaction is taken to model repulsive and attractive interactions between the units of the chains. Dynamics is introduced into the model by allowing for stochastic rotations of the beads of the chains, where the transition probability satisfies detailed balance and only such rotations are allowed which do not lead to any intersection of chains, in order to take entanglement restrictions into account. Although the chains treated by the simulation are very short (N = 16), with increasing density and/or decreasing temperature we do find a transition from a regime of essentially Rouse‐like dynamics (with decreased mobilities) to a glass‐like state, where the ’’monomer’’ displacements are very small and follow different power laws of time than in the Rouse model. We also treat the case where all chains apart from the mobile one are strictly frozen in, so tha.
Synthesis of Stereoisomers of 3‐Aminocyclohexanecarboxylic Acid and cis‐3‐Aminocyclohexene‐5‐carboxylic Acid

A practical synthesis of stereoisomers of 3-aminocyclohexanecarboxylic acid and cis-3-aminocyclohexene-5- carboxylic acid was achieved from cyclohexene-4-carboxylic acid via a key resolving approach with chiral 1-phenylethylamine.
Post-blast explosive residue-a review of formation and dispersion theories and experimental research

The presence of undetonated explosive residues following high order detonations is not uncommon, however the mechanism of their formation, or survival, is unknown. The existence of these residues impacts on various scenarios, for example their detection at a bomb scene allows for the identification of the explosive charge used, whilst their persistence during industrial explosions can affect the safety and environmental remediation efforts at these sites. This review article outlines the theoretical constructs regarding the formation of explosive residues during detonation and their subsequent dispersal and deposition in the surrounding media. This includes the chemical and physical aspects of detonation and how they could allow for undetonated particles to remain. The experimental and computational research conducted to date is presented and compared to the theory in order to provide a holistic review of the phenomenon.
Rotational reorientation dynamics of polar dye molecular probes by picosecond laser spectroscopic technique

Fluorescence lifetimes and rotational reorientation times for four structurally similar dye molecules—three monocations: cresyl violet, nile blue, and oxazine 720 and one neutral but polar: nile red—have been measured by picosecond time‐resolved fluorescence depolarization spectroscopy using the single‐photon counting technique, in a number of solvents, which included a wide range of alcohols, other hydrogen‐bonding liquids, and a few aprotic liquids. The rotational reorientation of the dye probes (assumed to be oblate ellipsoids) are sought to be explained in terms of the Stokes–Einstein–Debye theory and dielectric friction. The individual contributions to the rotational friction due to the above two factors were calculated using reasonable values for the molecular volume and dipole moment of the solute. The rotational behavior of all the four dyes in amides and aprotic solvents is reasonably well explained in terms of the simple stick hydrodynamic model with the ‘‘molecular volume’’ obtained by using th.