Miracle-dz/UniFAR-FTUs huggingface dataset:
An eddy cell model of mass transfer into the surface of a turbulent liquid

Experimental gas absorption studies for bubbles transported in turbulent pipe flow of water strongly indicate that liquid phase controlled mass transfer is due to surface renewal by turbulent eddies. Predictions of transport behavior from the conditions of turbulent flow cannot be made in support of this mechanism because no satisfactory theory of turbulent transport near a gas-liquid interface is available. This work considers a model of the hydrodynamic behavior near the surface which provides a link between the observed mass transfer behavior and the state of the turbulent field. In this model, the very small scales of turbulent motion are considered to be controlling. These motions are idealized, and their flow and mass transfer behavior are solved analytically. The overall result for eddies of various sizes is related to the turbulent energy spectrum by using only the easily accessible parameter ϵ, the energy dissipation rate. This model gives quantitative agreement to within a factor of 2 for three widely different experimental situations including gas-liquid and liquid-solid interfaces. However, the predicted Reynolds number dependence is somewhat higher than the experimental result. The model attempts to clearly define the basic physical process at the interface. Therefore, it indicates the direction for further experimentation needed to clarify the basic relationship between the mass transfer rates in the liquid phase and the hydrodynamic behavior of the turbulent liquid.
A New Tetracyclic Diterpene from Jatropha curcas

Jatrophodione A (1), a new diterpene with four rings, together with nine known compounds, caniojane (2), jatropholone A (3), jatropholone B (4), jatrogrossidione (5), 2-epijatrogrossidione (6), heudelotinone (7), gossweilone (8), (3 alpha)-3-hydroxy-ent-pimara-8(14), 15-dien-12-one (9), and 12-hydroxy-13-methylpodocarpa-8,11,13-trien-3-one (10), was isolated from the aerial parts of Jatropha curcas. Compounds 5, 6, 9, and 10 were found for the first time in this plant. Their structures were established by spectroscopic analysis, including 2D-NMR spectroscopic techniques. Cytotoxicities of compounds 1, 2, 7, 8, and 9 were tested on the three cancer cell lines A549, Hela, and SMMC-7721. Results showed that 7 exhibited cytotoxicity against SMMC-7721 with an IC(50) value of 21.68 mu m, whereas 7 and 8 were active against A549 with the IC(50) values of 16.04 and 20.47 mu m, and against Hela with the IC(50) values of 10.67 and 22.83 mu m, respectively.
Endocrine disrupting chemicals (phenol and phthalates) in the South African environment: a need for more monitoring

There has been increasing concern about the impacts of exposure to chemical compounds with endocrine disrupting activities in the environment, especially aquatic environments, to wildlife and humans. South Africa is known to have used and abused most chemicals listed by developed and developing countries as endocrine-disrupting chemicals. Endocrinedisrupting chemicals have been reported in water, sediment and serum, as well as in fish tissue samples, at a level that could trigger endocrine disruption in humans and wildlife. Although some monitoring has been reported, particularly in water systems within the country, information on EDCs in other environmental matrices is scanty. The water systems monitored so far are very few. The strongest economy in Africa, and an emerging world economy depending on agriculture, mining, manufacturing and industry, needs to focus more on monitoring and to strengthen government organs and institutions to monitor and ensure environmental safety. Keywords : Endocrine disrupting chemicals (EDCs), phenols, phthalates, monitoring, South Africa
The neutron small‐angle camera D11 at the high‐flux reactor, Grenoble

The neutron small-angle scattering system at the high-flux reactor in Grenoble consists of three major parts: the supply of cold neutrons via bent neutron guides; the small-angle camera D11; and the data handling facilities. The camera D11 has an overall length of 80 m. The effective length of the camera is variable. The full length of the collimator before the fixed sample position can be reduced by movable neutron guides; the secondary flight path of 40 m full length contains detector sites in various positions. Thus, a large range of momentum transfers can be used with the same relative resolution. Scattering angles between 5 × 10−4 and 0.5 rad and neutron wavelengths from 0.2 to 2.0 nm are available. A large-area position-sensitive detector is used which allows simultaneous recording of intensities scattered at different angles; it is a multiwire proportional chamber. 3808 elements of 1 cm2 are arranged in a two-dimensional matrix.
Interpreting IR Difference Spectra

From the evaluation of sample difference spectra based on Gaussian “model” peaks with known peak characteristics, it is shown that interpretation of some parameters from difference spectra, resulting from the ratioing or subtraction of a poor background spectra, may be inaccurate or misleading. Difference spectra of this type are commonly observed with the use of techniques such as subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS), electrochemically modulated infrared reflectance spectroscopy (EMIRS), or similar infrared spectroelectrochemical techniques, as well as some microsample analyses, studies of biochemical processes, and infrared astronomical observations, to name just a few examples. A mathematical evaluation of the problem is offered to demonstrate what information may realistically be gained from the characteristics of difference spectra. It is shown that in the worst case, where frequency, intensity, and peak width are all changing due to some perturbation of the sample (e.g., from temperature, or surface potential changes between background and sample spectra, etc.), even a qualitative interpretation may not be possible. In many practical cases, however, we show that at least a qualitative interpretation of the data can be obtained from difference spectra. Spectroelectrochemical applications for the calculations shown here are presented as examples, although these results impact a wider range of applications.
Evidence of a natural marine source of oxalic acid and a possible link to glyoxal

[1] This paper presents results supporting the existence of a natural source of oxalic acid over the oceans. Oxalate was detected in “clean-sector” marine aerosol samples at Mace Head (Ireland) (53°20′N, 9°54′W) during 2006, and at Amsterdam Island (37°48′S, 77°34′E) from 2003 to 2007, in concentrations ranging from 2.7 to 39 ng m−3 and from 0.31 to 17 ng m−3, respectively. The oxalate concentration showed a clear seasonal trend at both sites, with maxima in spring-summer and minima in fall-winter, being consistent with other marine biogenic aerosol components (e.g., methanesulfonic acid, non-sea-salt sulfate, and aliphatic amines). The observed oxalate was distributed along the whole aerosol size spectrum, with both a submicrometer and a supermicrometer mode, unlike the dominant submicrometer mode encountered in many polluted environments. Given its mass size distribution, the results suggest that over remote oceanic regions oxalate is produced through a combination of different formation processes. It is proposed that the cloud-mediated oxidation of gaseous glyoxal, recently detected over remote oceanic regions, may be an important source of submicrometer oxalate in the marine boundary layer. Supporting this hypothesis, satellite-retrieved glyoxal column concentrations over the two sampling sites exhibited the same seasonal concentration trend of oxalate. Furthermore, chemical box model simulations showed that the observed submicrometer oxalate concentrations were consistent with the in-cloud oxidation of typical marine air glyoxal mixing ratios, as retrieved by satellite measurements, at both sites.
The thermodynamic functions of ferroelectric and paraelectric SbSI

A first-principle method is used to calculate phonon density of states, Helmholtz free energy, internal energy, and entropy for ferroelectric and paraelectric SbSI. Theoretical phase transition temperature was obtained using the difference of the Helmholtz free energy, internal energy, and entropy term between ferroelectric and paraelectric phases on temperature. The obtained value is in reasonable agreement with the experimental second-order phase transition temperature Tc2 = 233 K.
Interval Partial Least-Squares Regression (iPLS): A Comparative Chemometric Study with an Example from Near-Infrared Spectroscopy

A new graphically oriented local modeling procedure called interval partial least-squares (iPLS) is presented for use on spectral data. The iPLS method is compared to full-spectrum partial least-squares and the variable selection methods principal variables (PV), forward stepwise selection (FSS), and recursively weighted regression (RWR). The methods are tested on a near-infrared (NIR) spectral data set recorded on 60 beer samples correlated to original extract concentration. The error of the full-spectrum correlation model between NIR and original extract concentration was reduced by a factor of 4 with the use of iPLS (r = 0.998, and root mean square error of prediction equal to 0.17% plato), and the graphic output contributed to the interpretation of the chemical system under observation. The other methods tested gave a comparable reduction in the prediction error but suffered from the interpretation advantage of the graphic interface. The intervals chosen by iPLS cover both the variables found by FSS and all possible combinations as well as the variables found by PV and RWR, and iPLS is still able to utilize the first-order advantage.
Novel Hybrid Electrocatalyst with Enhanced Performance in Alkaline Media: Hollow Au/Pd Core/Shell Nanostructures with a Raspberry Surface

In this paper, a hollow Au/Pd core/shell nanostructure with a raspberry surface was developed for methanol, ethanol, and formic acid oxidation in alkaline media. The results showed that it possessed better electrocatalyst performance than hollow Au nanospheres or Pd nanoparticles. The nanostructure was fabricated via a two-step method. Hollow Au nanospheres were first synthesized by a galvanic replacement reaction, and then they were coated with a layer of Pd grains. Several characterizations such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to investigate the prepared nanostructures. The intensive studies of fuel cells encouraged us to examine the electrocatalytic properties of the prepared nanostructures, and that alkaline media could supply a more active environment than acidic electrolyte in previous reports inspired us to operate the experiments in alkaline media. Accordi.
The gold/selenium system and some gold seleno-tellurides

The phase relationships in the gold/selenium system have been examined using X-ray powder diffraction techniques and differential thermal analysis. Only one stable phase, α-AuSe, is formed. A metastable modification of this compound, β-AuSe, is also formed by reaction of the elements. Both forms are monoclinic:α-AuSe: space group C2, Cm, or C2/m; a = 12.21 ± 2, b = 3.693 ± 4, c = 8.434 ± 6 A, β = 103.20 ± 3°; cell content, 8(AuSe). β-AuSe: primitive monoclinic (space groups P21 or P21/m are likely); a = 6.27 ± 1, b = 3.668 ± 4, c = 8.35 ± 1 A, β = 105.95 ± 13°; cell content, 4(AuSe). Both modifications decompose peritectoidally at ca. 400 °C. Gold and selenium form a monotectic at 754 °C at a composition just above 50 at. % selenium; some evidence was obtained for the presence of two liquid phases above the monotectic.Tellurium does not substitute in the AuSe lattice to a detectable extent. However, a ternary phase which includes the composition Au2SeTe is formed. Au2SeTe is primitive orthorhombic with a = .
Adhesion of TiC and Ti(C,N) coatings on steel

The scratch test has been used to measure the adhesion of CVD TiC coatings on various steels by comparing the critical load factors. The critical load (Lc) of a coating–substrate interface determined by the scratch test depends not only on the adhesion but also the substrate hardness and coating thickness. For identical deposition conditions, the coating thickness depends strongly on the carbide forming elements in the steel. In this work, a careful separation of these effects has allowed us to quantify the adhesion of a given system from the critical load. Of the nine steels tested, two had improved adhesion which was shown to be caused by diffusion of substrate elements into the coating. Adhesion measurements of Ti(C,N) coatings deposited by PVD are discussed and compared to the adhesion values of CVD TiC on the same steel substrates.
Estimating Annual River Discharge And Nitrogen Loadings To Danish Coastal Waters

A water balance analysis of 224 Danish catchments for the period 1989-97 revealed that the mean annual deviation between the climatic water balance (precipitation minus potential evapotranspiration) and the measured river discharge increases with decreasing catchment areas. Following exclusion of the smallest catchments <$>(\lt\! 10\,\hbox{km}^{2})<$>, a significant empirical relationship <$>(P \lt 0.0001)<$> was developed between annual river discharge at the catchment scale and various predictor variables (precipitation, antecedent precipitation, settlement areas, watercourse slope and the measure of the deviation between groundwater divide and topographic divide). Annual precipitation and the precipitation of the previous year explained 50% and 10%, respectively, of the annual river discharge. The explanatory variables included in the final river discharge regression equation were selected from an initial set of 26 variables based on a Monte-Carlo analysis of 1000 randomly derived sub-sets of annual river discharge. The annual river discharge model was evaluated for monitored areas and applied together with a previously developed nitrogen loss model to unmonitored areas covering more than <$>20,\! 000\,\hbox{km}^{2}<$> within 9 Danish coastal catchments. The results obtained were compared to previous estimations of runoff and nitrogen loading.
Export Scope and Characteristics of Destination Countries: Evidence from German Transaction Data

: This paper uses information on export transactions by German firms from 2011 to document the role of characteristics of destination countries for export scope, where export scope is defined as the number of different products a firm exports to a destination market. It demonstrates that in line with theoretical hypotheses intra-firm differences in export scope across destination countries are related to differences in the distance between Germany and the countries of destination, differences in the economic size and the per capita income of these countries, and in the ease of doing international trade with the countries.
STEM and EDXS Characterization of Physico‐chemical Reactions at the Periphery of Bioactive Glass Particles in Contact with Biological Fluids

Abstract Knowledge of the local concentration and species of ions released at the bioactive glass particles/biological fluids interface is essential to the understanding of the complex interfacial reactions and physico‐chemical properties of bioactive glasses. This work characterises the interface that bioactive glass particles develop after immersion into biological fluids for different delays (1, 2, 4, 28 days). The distribution of silicon, phosphorus, calcium, and aluminum varied across bioactive particles periphery. After 1 day of immersion into biological fluids, a Si–Al rich layer appeared at the bioactive glass surface. After 2 days, significantly higher concentrations of Ca and P are observed on top of this newly formed Si–Al layer, compared to the center of the glass particles. Then, an apatite (Ca–P) layer starts to build up and grows with time after immersion into biological fluids. The Ca/P atomic ratio increases with time from 1 to 1.6. A thick Ca–P rich layer was formed after 28 days. The Ca–P layer appeared to be generated by calcium and phosphate ions diffusing through the Si–Al layer, which contain at least traces of these ions.
The Fully Developed Wake of a Circular Cylinder

Extending previous work on turbulent diffusion in the wake of a circular-cylinder, a series of measurements have been made of the turbulent transport of mean stream momentum, turbulent energy, and heat in the wake of a cylinder of 0.169 cm. diameter, placed in an air-stream of velocity 1280 cm. sec. -1. It has been possible to extend the measurements to 960 diameters down-stream from the cylinder, and it 1s found that, at distances in excess of 600 diameters, the requirements of dynamical similarity are very nearly satisfied. To account for the observed rates of transport of turbulent energy and heat, it is necessary that only part of this transport be due to bulk convection by the slow large-scale motion of the jets of turbulent fluid emitted by the central, fully turbulent core of the wake, which had been supposed previously to perform most of the transport. The remainder of the transport is carried out by the small-scale diffusive motion of the turbulent eddies within the jets, and may be described by assigning diffusion coefficients to the turbulent fluid. It is found that the diffusion coefficients for momentum and heat are approximately equal, but that for turbulent energy is considerably smaller. On the basis of these hypotheses, it is possible to calculate $he form of the mean velocity distribution in good agreement with experiment, and to give a qualitative explanation of the apparently more rapid diffusion of heat.
Synchrotron radiation topographic observation of KTiOPO4 crystals under an electric field

In situ white-beam synchrotron radiation topographic observations under an electric field have been made on the KTiOPO4 (KTP) family of crystals. The investigation shows a strong enhancement of diffracted intensity for hkl reflections (l ≠ 0) and topographic contrast in the form of fine striations when the external electric field is parallel to the polar axis. Several kinds of doped and undoped samples with various grown-in defects, such as domain boundaries, growth striations, growth-sector boundaries, dislocations, etc., have been studied in detail. The results suggest that these defects have very little effect on the field-induced striations. It is believed that the movement of K^+ ions driven by the electric field leads to a local accumulation of charges and a lattice distortion. The strongly anisotropic conductivity is a governing factor in the explanation of the field-related phenomena in this kind of quasi-one-dimensional conductor.
Selective aerobic oxidation of the biomass-derived precursor 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under mild conditions over a magnetic palladium nanocatalyst

A new method for the selective aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) has been developed employing a magnetically separable [γ-Fe2O3@HAP-Pd(0)] catalyst. The catalyst was prepared by the exchange of Pd2+ with Ca2+ in γ-Fe2O3@HAP, followed by reduction of the Pd2+ to Pd(0) nanoparticles, and well characterized by TEM, XRD and XPS. The catalyst showed high activity in the oxidation of HMF to FDCA in water, with 97% HMF conversion and a 92.9% yield of FDCA under optimal reaction conditions. The method developed has demonstrated some advantages, including its sole requirement of a stoichiometric base, and high catalytic performance under atmospheric oxygen, even in air. More importantly, the γ-Fe2O3@HAP-Pd(0) catalyst was readily separated from the reaction solution using an external magnetic field and was successfully reused during five consecutive reaction runs while retaining its catalytic effectiveness. This study provides a green and sustainable method for the production of valuable chemicals from renewable resources.
Digital-circuit analysis of short-gate tunnel FETs for low-voltage applications

This paper investigates the potential of tunnel field-effect transistors (TFETs), with emphasis on short-gate TFETs, by simulation for low-power digital applications having a supply voltage lower than 0.5 V. A transient study shows that the tunneling current has a negligible contribution in charging and discharging the gate capacitance of TFETs. In spite of a higher resistance region in the short-gate TFET, the gate (dis)charging speed still meets low-voltage application requirements. A circuit analysis is performed on short-gate TFETs with different materials, such as Si, Ge and heterostructures in terms of voltage overshoot, delay, static power, energy consumption and energy delay product (EDP). These results are compared to MOSFET and full-gate TFET performance. It is concluded that short-gate heterostructure TFETs (Ge–source for nTFET, In0.6Ga0.4As–source for pTFET) are promising candidates to extend the supply voltage to lower than 0.5 V because they combine the advantage of a low Miller capacitance, due to the short-gate structures, and strong drive current in TFETs, due to the narrow bandgap material in the source. At a supply voltage of 0.4 V and for an EOT and channel length of 0.6 nm and 40 nm, respectively, a three-stage inverter chain based on short-gate heterostructure TFETs saves 40% energy consumption per cycle at the same delay and shows 60%–75% improvement of EDP at the same static power, compared to its full-gate counterpart. When compared to the MOSFET, better EDP can be achieved in the heterostructure TFET especially at low static power consumption.
An alternative encapsulation approach for production of active chitosan–propolis beads

Summary Encapsulation is a promising technology to carry natural active substances, preventing their loss and maintaining their stability until use. Beads of chitosan-containing propolis have been prepared using a mono-pore filter device, which permits the encapsulation of natural polyphenols avoiding heat treatments, high shear rates and the use of toxic solvents. Beads proved to be active against Bacillis cereus, Escherichia coli, Listeria innocua, Pseudomonas fluorescens, Yarrovia lipolytica and three moulds strains; the highest effect was found against Staphylococcus aureus (MIC 0.8 mg beads mL−1). Results in liquid cultures of S. aureus evidenced that beads were able to release the flavonoids from propolis: the diffusion of the active compounds is a key factor in the exploitation of the microbial activity. The obtained chitosan–propolis beads represent an example of natural antimicrobial delivery system that could be used to prevent the growth of pathogenic/spoilage bacteria in food applications.
Migration from polyethylene terephthalate under all conditions of use

The condition of time and temperature under which PET (polyethylene terephthalate) is used in food contact applications is reviewed. The effect upon overall migration into fat simulants of varying temperature, time, thickness and crystallinity of the PET is discussed, with experimental data. Specific migration of monomers, catalyst residues, colourants and acetaldehyde from PET into food simulants is reported.