Miracle-dz/UniFAR-FTUs huggingface dataset:
Integration of Fe in natural and synthetic Al-pyrophyllites: an infrared spectroscopic study

Abstract Numerous studies focus on the relationships between chemical composition and OH-band positions in the infrared (IR) spectra of micaceous minerals. These studies are based on the coexistence, in dioctahedral micas or smectites, of several cationic pairs around the hydroxyl group which each produce a characteristic band in the IR spectrum. The aim of this work is to obtain the wavenumber values of the IR OH vibration bands of the (Al-Fe3+)-OH and (Fe3+-Fe3+)-OH local cationic environments of ‘pyrophyllite type’ in order to prove, disprove or modify a model of dioctahedral phyllosilicate OH-stretching band decomposition. Natural samples are characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies and electron microprobe; the hydrothermal synthesis products are also analysed by powder XRD and FTIR after inductively coupled plasma measurements to obtain the chemical compositions of starting gel phases. Natural samples contain some impurities which were eliminated after acid treatment; nevertheless, a small Fe content is found in the pyrophyllite structure. The amount of Fe which is incorporated within the pyrophyllite structure is much more important for the synthetic samples than for the natural ones. The IR OH bands were clearly observed in both natural and synthetic pyrophyllites and assigned to hydroxides bonded to (Al-Al), (Al-Fe) and (Fe-Fe) cationic pairs. During this study, three samples were analysed by DTG to check the cis- or trans-vacant character of the layers and to determine the influence of this structural character on the OH-stretching band position in IR spectroscopy.
Sulfur- and Oxygen-Induced Alterations of the Iron (001) Surface Magnetism and Work Function : A Theoretical Study

The electronic structure and magnetic properties of atomic sulfur and oxygen adsorbed on the iron (001) surface are examined using density functional theory (DFT). The sulfur/oxygen coverage is considered from a quarter of one monolayer (ML) to a full monolayer. The work function change, magnetic properties, and density of states are determined and compared. We find that the work function increases with sulfur coverage in agreement with experiment. We also find that sulfur interacts strongly with the surface layer and that the magnetic moment of the Fe surface decreases as the sulfur coverage increases. In the case of oxygen adsorption, we find that the magnetic moment of the surface Fe atoms instead increases. We show that the difference in surface magnetic moment between sulfur adsorption and oxygen adsorption can be simply explained combining the Slater-Pauling rigid band model linking d-occupation and magnetic moment with an electronegativity argument. Moreover, the work function of the Fe surface as a function of oxygen coverage is found to be very sensitive to overlayer arrangement, here seen in the cases of 0.5 ML c(2 x 2) and 0.5 ML p(2 x 1). This is shown to result from large differences in the surface dipole moment change induced by the oxygen adsorption in the two different overlayer arrangements.
Stabilization of Water‐Soluble Antioxidant in Water‐in‐Oil‐in‐Water Double Emulsions

Abstract In this study, we are introducing a method that can effectively stabilize antioxidants in water‐in‐oil‐in‐water (W/O/W) double emulsions. Preliminarily, stable W/O/W double emulsions were produced by manipulating the characteristics of internal aqueous phase via two‐stage emulsification, resulting consequently in the formation of fine internal water droplets in the dispersed oil droplets. From conductivity measurements that can determine the elution amount of internal aqueous phase, it was confirmed that the double emulsion stability could be improved by treating the internal aqueous phase with a hydroxypropyl‐beta‐cyclodextrin. In this study, kojic acid, 5‐hydroxy‐2‐(hydroxymethyl)‐4‐pyrone was selected as a model antioxidant. The stabilization of kojic acid was attempted by locating it in the internal water droplets of the stable W/O/W double emulsions. The stability of kojic acid in the double emulsion system could be maintained at 90% for 10 weeks at high temperature. We believe that these stable W/O/W double emulsions could be used meaningfully as a carrier for many unstable antioxidants.
How profitable is dairying in tribal Chhattisgarh?

The study estimated the costs, returns and determinants of milk production in tribal region of Chhattisgarh using household level data from 300 farmers of two tribal districts namely Koriya and Surguja. Study found that dairy animals, particularly indigenous animals were maintained poorly, largely feeding on poor quality common property resources. Cost of milk production was estimated to be highest in buffalo (Rupees 29.12/litre) and lowest in crossbred cow (Rupees 20.97/litre). The rearing of local cows and buffalo for milk production as business was not profitable due to low productivity. However, higher opportunity costs of rearing these animals (Rupees 14.51/litre in buffalo andÂ Rupees 18.58/litre in local cow) may generate significant employment opportunity and additional income among the tribal farmers. The crossbred animals are economically viable at least in the short-run. But if the productivity of these animals does not increase it is likely that in the times to come, the returns will not be even sufficient to cover the rising feed and fodder costs. Positive and significant coefficients of concentrates and green fodder with respect of milk production indicate high priority to be given on these aspects by various ways like availability of seed on improved fodder, creating awareness on balance feeding, institutional arrangement for improving quality of common property resources etc.
Organophosphonic acids as viable linkers for the covalent attachment of polyelectrolyte brushes on silica and mica surfaces

We report the first successful preparation of polyelectrolyte brushes using an ATRP initiator that was covalently grafted to silica and mica substrates via an organophosphonic acid. Covalent attachment of the initiator to silica and mica and the subsequent synthesis of polyacrylic acid (PAA) and poly(sulfopropyl methacrylic acid) brushes by water mediated-ATRP were confirmed by ATR-FTIR, ellipsometry, AFM, and contact angle measurements. The initiator–substrate bond was robust and could resist a large range of pH in the absence of salt. Interactions between PAA brushes anchored to mica via the organophosphonic acid initiator were investigated using a surface forces apparatus. The results confirmed the robustness of the initiator–mica bond as the brushes could resist shearing and compression under relatively high applied loads.
Sensitivity Analysis of a Fixed Bed Combustion Model

The ability to model the combustion of biofuels in a fixed bed is evaluated by a sensitivity analysis. The analysis treats the uncertainty of model parameters related to heat transport, reaction rates, and composition of volatiles. The scatter of the parameters is estimated from the differences between several published correlations. The results are compared with measurement data and possible model simplifications are discussed. It is shown that the bed model is able to reproduce the ignition rate and the maximum temperature. Prediction of these properties is relatively insensitive to the uncertainty of most of the parameters. Gas concentrations within the bed are more difficult to predict. They are greatly influenced by the composition of the volatile gas released during devolatilization. Also the composition of the volatile gas has a significant influence on the ignition of the gas in the model, affecting the ignition rate, particularly at low airflows. Moreover, the investigation shows that treatment of radiation can be simplified, and the number of gas species included in the model can be restricted without significant losses of model generality.
Cross-Stream Radial Fluid Injection into a Round Jet

An experimental flow visualization study using laser-induced fluorescence technique has been carried out to investigate the effects and flow structures resultant of the interactions between cross-stream secondary radial fluid injections into a primary round jet. Both continuous and pulsed secondary injections of up to eight and four percent of the primary jet mass flow rates respectively are used in the study. Streamwise flow visualization results along the symmetry plane suggested that continuous injections are able to weaken or even impede the generation of large-scale vortex structures in the near-field of the primary jet with increasing injection rates, with corresponding reduction in the primary jet potential core length. Interest in the flow mechanism and the effectiveness of mass and momentum transport between the primary jet and secondary injections led to cross-stream flow visualization downstream of the primary jet as well. Observations indicated that at intermediate injection rates, the counter-rotating vortex-pair formed by the deflected secondary injections are able to entrain and transport ambient fluid into the primary jet core. Follow-up studies on pulsed excitation suggested that a dramatic increase in jet-spread is possible using ‘flapping’-like excitations. It is postulated that a combination of large- and small-scale flow structures resultant of the excitation is responsible for the enhanced jetmixing.
The biogeochemical cycling of formic and acetic acids through the troposphere: an overview of current understanding

Despite remaining uncertainties, a general picture of the biogeochemical cycling of HCOOH and CH 3 COOH is beginning to emerge. These acids are ubiquitous vapor- and aqueous-phase constituents of the global troposphere, contributing significant fractions of the natural acidity in precipitation and cloudwater, particularly in continental regions of the tropics and subtropics. The similarity of concentrations in remote and impacted regions indicates that anthropogenic emissions of carboxylic acids or precursors are probably not important sources over broad geographic areas. In continental regions, seasonally varying emissions of acids and hydrocarbon precursors from vegetation are thought to represent major sources for both acids. In marine areas, the seasonality of wet deposition and apparent lack of transport from continents support the hypothesis of a marine biogenic source. Ratios of total (aqueous + vapor) concentrations of HCOOH versus CH 3 COOH in clouds vary as a function of H + . This observation is consistent with the hypothesis of a pH-dependent aqueous-phase source and sink for HCOOH in clouds which may act to stabilize aqueous-phase ratios against shifts in solution Ht. Large die1 periodicities in the concentrations of vapor-phase species over continents, together with a lack of evidence for long-distance transport, suggest that HCOOH and CH 3 COOH experience short atmospheric lifetimes of several hours to a few (at most) days. Because they are important controllers of free acidity and represent a potentially large sink for aqueous-phase OH radicals, the cycling of the carboxylic acids is expected to interact directly and indirectly in the chemical cycling of other atmospheric constituents. DOI: 10.1111/j.1600-0889.1988. tb00106.x
Regional trends in terrestrial carbon exchange and their seasonal signatures

The trends of terrestrial carbon exchange and their mechanistic drivers are key components in understanding how carbon reservoirs will respond to climate change. Here we show trends in seasonal non-fossil land-atmosphere carbon exchange from 1980 to 2008 using atmospheric CO2 inversion results. Four indices were analysed: growing-season net flux (GSNF), dormant-season net flux (DSNF), amplitude and annual net carbon flux (NCF). We find that the global land carbon sink is intensifying at -0.057 ± 0.01 PgC yr-2, resulting in -1.65 ± 0.29 PgC of additional uptake over the period examined. This increased total land uptake is driven by a decline in the DSNF (-0.04 ± 0.01 PgC yr-2) and intensification of the GSNF (-0.02 ± 0.008 PgC yr-2). Regional analysis shows the dominant role of the southern half of the African continent; intensification of the GSNF (-0.02 ± 0.005 PgC yr-2) and a decline in the DSNF (-0.013 ± 0.004 PgC yr-2) imply that Africa has shifted from a net carbon source in the 1980s to near-neutral emissions. By contrast, a weakening of the GSNF is found in temperate North America (0.015±0.007 PgC yr-2) and tropical America (0.01 ± 0.005 PgC yr-2).
Growth Characteristics and Properties of TiN Coating by Chemical Vapor Deposition

Titanium nitride films obtained by chemical vapor deposition with TiCl{sub 4}, N{sub 2}, and H{sub 2} as gas sources at ambient pressure have been examined in this study. The results reveal that the deposition rate increases with increasing H{sub 2} and N{sub 2} partial pressures but has a maximum value with TiCl{sub 4} partial pressure. The Arrhenius plots show that the transition temperature from surface limited to diffusion limited is greatly influenced by H{sub 2}, N{sub 2}, and TiCl{sub 4} partial pressures. The film microstructurre was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It is found that the change of topography and microstructure of TiN films responds to deposition temperature and gas concentration used. The diffusion rate of as-deposited atoms and the total surface energy are considered as the determinant factors for the change. The growth texture of TiN films was identified to be {l_brace}422{r_brace} at lower deposition temperature and {l_brace}200{r_brace} at high temperature. The mechanisms for texture formation are discussed.
Co-occurrence of fumonisins and T-2 toxins in milling maize fractions under industrial conditions

Latest studies indicate frequent co-contamination of food and feed supplies. The aim of this study was to investigate the natural co-occurrence of fumonisins (FB) and T-2 toxins in maize milling fraction obtained under industrial conditions. Both mycotoxins were identified in all tested samples and the FB level was higher than T-2 toxin. This fact was reflected in the content of mycotoxins in milling end products (extra maize meal, superior maize meal, and maize flour) and in hominy feed fractions. Results revealed that mycotoxins are concentrated in the hominy feed fraction, while the lowest level of mycotoxins was identified in the extra maize meal that contains coarse particle, have uniform fineness and low fat content.
Phosphorus sorption in Natal soils

Phosphorus (P) sorption poses a severe constraint on the ability of many soils to supply adequate amounts of P to plants. In an effort to quantify the P sorption capacities of soils in Natal, P sorption isotherms of 50 topsoils from a number of localities in the province were established. The amount of P sorbed at a solution P level of 0.2 mg P L−1, defined as the standard P requirement, varied from 5 to 1174 mg kg−1. Standard P requirement was greatest in highly weathered clay soils and lowest in sands. Various soil parameters were correlated with standard P requirement and isotherm slope at 0.2 mg P L−1. Oxalate-extractable aluminium, organic matter and sample density gave the best correlations. Because the method for the determination of sorption isotherms is tedious and does not lend itself to routine use, the feasibility of predicting the isotherm slope by near infra-red reflectance spectroscopy was also investigated. Preliminary results were encouraging and a calibration based on the samples used in.
Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism

Fluorescence emission and excitation spectra of para-phenylene vinylenes nPV with n=1–4 styryl units are investigated experimentally and theoretically as a function of the temperature and the polarizability of the solvent. At low temperatures, the vibronic structures of the S0↔S1 emission and excitation bands are mirror symmetrical with negligible 0–0 energy gaps. The frequencies of the prominent vibrational modes are assigned to the second longitudinal acoustic phonon modes of the entire molecules and to localized carbon–carbon stretching vibrations. The complete vibronic structures of the spectra are calculated at the ab initio Hartree–Fock (HF/6-311G*) and restricted configuration interaction singles (RCIS/6-311G*) levels of theory assuming planar C2h molecular symmetry. The theoretically predicted spectra are in good agreement with the experiments. At room temperature, a 0–0 energy gap between the first band maxima opens, and the mirror symmetry between absorption and emission is lost. The vibronic ba.
Temperature quenching of CDOM fluorescence sensors: temporal and spatial variability in the temperature response and a recommended temperature correction equation

Field‐based instruments measuring chromophoric dissolved organic matter (CDOM) fluorescence are often used as a proxy for dissolved organic carbon concentrations in lakes and streams. CDOM fluorescence yield is, however, affected by water temperature at the time of measurement, a factor which varies on both diel and seasonal timescales. A temperature correction must therefore be applied to these data. We present data on temporal and site‐specific variability in temperature quenching of CDOM fluorescence for water from a humic lake and one of its main inflows in the west of Ireland. In addition, we present a temperature compensation equation and show that this equation is an improvement on methods previously proposed.
GAS HOLDUP AND VOLUMETRIC LIQUID-PHASE MASS TRANSFER COEFFICIENT IN A GEL-PARTICLE SUSPENDED BUBBLE COLUMN WITH DRAUGHT TUBE

The effects of column dimensions, gas velocity and properties of the liquid and the solid particles on the gas holdup eG and the volumetric liquid-phase mass transfer coefficient kLa in a solid suspended bubble column with a draught tube and a conical bottom were studied experimentally in a liquid-solid batch operation. The presence of suspended solid particles in the column reduces the values of eG and kLa, and their reduction due to the addition of solid particles to the column increases with increasing solid concentration and terminal velocity of a single particle. Based on these observations, empirical equations for eG and kLa are proposed which are applicable to columns with diameter of 0.1-0.3 m.
The Recombination Reaction between Hydroxyl Radicals and Nitrogen Dioxide. OH + NO2 + M (= He, CO2) in the Temperature Range 213–300 K

Rate constants for the reaction between hydroxyl radicals and NO2 have been determined in the temperature range 213 to 300 K using a discharge flow system with resonance fluorescence detection of OH. The third order rate constant k10 at 300 K was found to be (1.0 ± 0.4) 10−30 cm6 · s−1 and (4.0 ± 0.5) 10−30 cm6 · s−1 for He and CO2, respectively. The temperature dependence of the low pressure limiting rate constant with helium as a third body may be expressed in the form Rate constants for the quenching of the A2 ∑+ state of the hydroxyl radical by nitrogen and CO2 are also reported. Geschwindigkeitskonstanten fur die Reaktion zwischen OH-Radikalen und NO2 im Temperaturbereich 213–300 K wurden in einem Stromungssystem mit Nachweis des OH durch Resonanzfluoreszenz gemessen. Die Geschwindigkeitskonstanten dritter Ordnung (k10 sind bei 300 K: (1,0 ± 0,4) 10−30 cm6 · s−1 fur M = He und (4.0 ± 0.5) 10−30 cm6 · s−1 fur M = CO2. Die Temperaturabhangigkeit der Geschwindigkeitskonstanten im Niederdruckbereich fur He als Stospartner kann durch beschrieben werden. Geschwindigkeitskonstanten fur die Fluoreszenzloschung des A2 ∑+-Zustandes des OH-Radikals durch N2 und CO2 wurden ebenfalls gemessen.
Gas Mixtures and Ozone Production in an Electrical Discharge

Abstract The quantitative production of ozone (O3) with N2, O2, and Ar gas mixtures in an atmospheric pressure corona discharge (CD) is investigated. A five-part model is presented that explores the discharge conditions needed for optimum ozone production. One part of the model is the well-known relationship that correlates the discharge's voltage, frequency, gap, dielectric material, etc with the generator's yield. The four other parameter's revolve around the correct selection of the gas mixture, which subsequently effect's the discharge's ionization potential, continuum background, excitation of atomic and molecular species, and gas cooling efficiency. Varying the ratios of the three basic components of air (N2, O2) and Ar) is demonstrated to have a pronounced effect on ozone production in a modified CD.
Synthesis and Characterization of Long Chain Branched Isotactic Polypropylene via a Metallocene Catalyst and T-Reagent

Long chain branched isotactic polypropylenes (LCBPP) prepared via the combination of rac-Me2Si(2-Me-4-Ph-Ind)ZrCl2/MAO catalyst and a p-(3-butenyl)styrene (T-reagent) were characterized to investigate their synthesis, structure, solution properties, and melt properties. The T-reagent, in the presence of hydrogen, simultaneously served as a comonomer and chain transfer agent, resulting in a LCBPP with high molecular weight, desirable branch point density, and relatively well-defined molecular structure. Additionally, the metallocene catalyst remained highly reactive. To understand the structure−property relationships, a series of LCBPPs were prepared with similar weight-average molecular weights of about 250 000 g/mol and different branch densities ranging from 0 (linear iPP) to 3.3 branch points per 10 000 carbons. 1H NMR and SEC equipped with triple detectors revealed structural information. Melt properties were examined by small-amplitude dynamic oscillatory shear and extensional flow measurements. LCBP.
Entrepreneurship and higher education: an employability perspective

This paper argues that entrepreneurship can be seen as a special form of employability. When universities and colleges promote employability, they are also promoting elements of entrepreneurship. However, if this is to lead to self-employment, more is needed. Students need to understand what it means to be self-employed, what sources of help are available and where the main pitfalls lie. Higher education already does something to meet these needs but provision is restricted and not, in practice, equally available to all students. The lack of systematic research in this area means that there is a shortage of evidence about interesting and effective practices; about ‘quality signals’ - indicators that provision is of the highest quality; and about the connections between entrepreneurship, employability and mainstream higher education curricula in all subject areas at postgraduate and undergraduate levels.
Kinetic Modeling Study of Polycyclic Aromatic Hydrocarbons and Soot Formation in Acetylene Pyrolysis

The aim of this kinetic work is a critical and detailed analysis of the acetylene pyrolysis in a wide range of conditions, especially from 900 to 2500 K, in order to further validate and refine the kinetic mechanism of C2–C4 acetylenic species. In particular, the successive reactions of the intermediate products, such as C4 species and polyynes, were especially investigated to better understand the primary C2H2 kinetics. The subsystem of acetylene pyrolysis reactions clearly constitutes an important portion in the overall kinetic scheme and also a crucial topic in the further extension of the model toward the formation of polycyclic aromatic hydrocarbons (PAHs) and soot particles. The analysis of acetylene experiments, often with the formation of large amount of soot, requires the coupling of the gas phase kinetic scheme with a soot kinetic model. The gas-phase kinetics involves the formation of the first polycyclic aromatic hydrocarbons up to the first components of the soot kinetic mechanism (C20H16 and.