Miracle-dz/UniFAR-FTUs huggingface dataset:
Characterization of an iron smelting slag from Zimbabwe by Raman microscopy and electron beam analysis

A sample of archaeological iron slag from Northern Zimbabwe was characterised by Raman microscopy (RM) and electron beam analysis (EBA). The phases identified in a slag found at an ironmaking site not only reflect the chemical composition of the slag but can also provide crucial information regarding the reconstruction and interpretation of the metallurgical operations, such as the prevailing redox conditions in a furnace at the time of cooling. Free iron oxides, such as haematite, magnetite and wustite, are important indicators of these redox conditions. But while classical techniques of phase identification can be used to identify the different iron oxides, they cannot distinguish between dissimilar oxidation states due to their non-stoichiometric nature, and also the effect of substituting elements in iron oxides. RM proved invaluable in both respects. By combining the results provided by RM and EBA, it was possible to identify (1) the free iron oxides, haematite and magnetite in the original ore, and magnetite and wustite in the slag, (2) oxidised magnetite and wustite, characterized by a shift to higher wavenumbers of their intense characteristic Raman bands and (3) Al3+-substituted magnetite and a solid solution between magnetite and hercynite (FeAl2O4). This pilot study aims to develop a model that enables close identification of the redox conditions by analysing the free iron oxides from a variety of smelting processes. It is hoped that this will provide an independent and quantifiable criterion to distinguish smithing slags (more oxidising) from smelting slags (more reducing), and to understand better the actual smelting process that transforms highly oxidised iron ore to fully reduced iron metal.
THE OCCURRENCE OF INTERLAYER CLAY‐ORGANIC COMPLEXES IN TWO NEW ZEALAND SOILS

By using x-ray diffractometry and 13C-NMR spectroscopy, in combination with chemical and heat pretreatments, we have found good evidence for the occurrence of interlayer clay-organic complexes in two New Zealand soils. Here, the clay mineral is a regularly interstratified mica-smectite, and the organic species is a humic substance with a polymethylene chain structure. The organic material in the complex is resistant to peroxidation and pyrophosphate extraction. It is also thermally stable, being extensively decomposed only after the complex is heated at 400°C. A combination of soil factors seems necessary for interlayer complex formation. This includes a smectitic clay mineralogy, an accumulation of organic matter associated with a low microbial activity, and a highly acid soil reaction.
Near infrared labeling of PLGA for in vivo imaging of nanoparticles

To introduce optical imaging among methods available to follow nanoparticle biodistribution, we have evaluated the concept of covalently labeling poly(lactide-co-glycolide) (PLGA) with a near-infrared (NIR) dye to obtain stable NIR fluorescent nanoparticles. PLGA was coupled with the NIR dye (DY-700, Dyomics) by an amide bond with 38% efficiency. Incorporating 1% of this conjugate into PLGA nanoparticles stabilised by polyvinyl alcohol (PVA) leads to stable nanoparticles (NPs) without affecting their colloidal characteristics (average diameter, polydispersity and zeta potential). In addition, nanoparticles remain strongly fluorescent and display good storage stability for 4 weeks at 4 °C or over one week at 37 °C. Nanoparticle cytotoxicity evaluated using HUVEC, NIH/3T3 and J774.A1 cell lines was similar for unlabeled or labeled NPs. Fluorescent nanoparticles and free dye were injected intravenously into mice and their biodistribution was followed for 24 h by NIR imaging, in vivo and ex vivo. Nanoparticles were found mainly in the liver whereas the free dye was not accumulating preferentially in this organ. The DY-700 NIR conjugate incorporated into PLGA NPs shows good performance both in vitro and in vivo, thus paving the way to finely traceable PLGA nanosystems for in vivo administration.
Characteristic and Molecular Recognition Mechanism of Theophylline Monolithic Molecularly Imprinted Polymer

Abstract A monolithic molecularly imprinted polymer (MIP) with specific recognition ability for theophylline was prepared by in‐situ therm polymerization, using acrylamide as a functional monomer, ethylene glycol dimethacrylate as a cross‐linking agent, toluene and dodecanol as porogenic solvents and 2,2′‐azobisisobutyronitrile as initiator. Scanning electron microscopy and an accelerated surface area and porosimetry system were used to identify the structural features of the MIP. The results show that the large through‐pore structure allows mobile phase to flow through the MIP column with a low back pressure, and the other pores lead to the molecular recognition. Some chromatographic conditions such as the composition of the mobile phase, flow rate, and temperature were characterized and illustrated by a homologous series of xanthine derivatives, theophylline and caffeine. Effects of molecular recognition were also discussed and the possible recognition mechanisms were hydrogen bonding and hydrophobic interactions between the theophylline molecule and the MIP.
The chemical structure of premixed fuel-rich methane flames: the effect of hydrocarbon species in the secondary reaction zone

In a previous paper the analysis of a fuel-rich, ф =1.60, methane flame using a four-stage molecular beam inlet to a quadrupole mass spectrometer was described. The results were used to investigate the chemical structure of the primary reaction zone of the flame. In this paper, results from a richer flame, ф = 2.00, are presented and analysed. This premixed, laminar, flat flame had the following composition (all molar percentages) and conditions: 35.0% (CH4), 35.0% (O2), 30% (Ar); pressure = 8.00 kPa; cold-gas velocity at 293 K = 0.47 m s-1. Mole fraction profiles through each flame were measured for a large number of stable and radical species, and those for the ф = 2.00 flame are presented in this paper and are compared with the results from the ф = 1.60 flame published earlier. Analysis and discussion in the present paper concentrates on the secondary reaction zone of both fuel-rich flames. Comparison of the profiles shows that hydrocarbon species survive the primary reaction zone in increasing concentrations as ф increases. It is shown that the reaction H + O2 ⇌ OH + O (21, -21 ) does not achieve the partial equilibrium condition that is found in leaner flames, although the remaining bimolecular reactions of the H2-O2 system do so. The competition between various species for the H, O and OH radicals is analysed using a convenient parameter which allows comparison of reaction rates and which has been called the 'characteristic reaction time’, r. It is concluded that the direct cause of the inability of (21, -21) to achieve partial equilibrium is the removal of O atoms from the available pool of H, O and OH radicals by reaction with hydrocarbon species, particularly C2H2. The rate of decrease of the H atom concentration in the secondary reaction zone is shown to be too fast to be the result of termolecular recombination reactions; it is suggested that the cause is the rapid response of the fast bimolecular reactions of the H2-O2 system to the removal of O atoms via OH + H → O + H2, (-22) OH + OH → O + H2O (-23) thus reducing the concentrations of H and OH radicals. This mechanism explains the reduction in the excesses of the H, O and OH radicals above their thermodynamic equilibrium levels that is observed with increasing ф. It is concluded that it is possible to view a rich flame as consisting entirely of an extended primary reaction zone in which the concentrations of the H, O and OH radicals are controlled by bimolecular reactions throughout.
Viscosities of Aqueous NaCl Solutions Containing CO2 at High Pressures

Viscosity measurements of aqueous NaCl solutions containing CO2 along three isotherms at 273 K, 276 K, and 278 K at pressures up to 30 MPa are reported. The measurements have been carried out within a falling capillary type viscometer and have an estimated uncertainty of ±0.8%. The experimental values were correlated in terms of pressure, temperature, and concentrations of NaCl and CO2. The correlation reproduces the experimental values to within ±1.3%.
A test of a winter farm management option for mitigating nitrous oxide emissions from a dairy farm

A trial was conducted in 2004 and 2005 to evaluate the effect of a stand‐off winter stock management system on nitrous oxide (N2O) emissions from a dairy farm in New Zealand. The management system consisted of removing cows from pasture after grazing for 6 h per day and keeping them on a stand‐off pad for the rest of the day during the late autumn/winter seasons in order to reduce soil physical damage because of grazing on wet soils. The N2O emissions were measured on pasture that was grazed either for all day or for 6 h. The N2O emissions from the stand‐off pad were also measured. A closed chamber technique was used for measuring N2O fluxes. The New Zealand International Panel for Climate Change inventory methodology was used to calculate annual N2O emissions from land application of farm effluent, leached and volatilized N. Significantly lower (P < 0.05) N2O emission rates were found when the stand‐off grazed pasture was compared to the control in the winter seasons when soil was wet. Total N2O emission rates measured over one grazing interval in the late autumn/winter (May–August) in 2004 were 2.72 and 1.21 kg N2O‐N/ha for the control and the stand‐off grazed pastures, respectively. The respective emissions in 2005 were 0.97 and 0.22 kg N2O‐N/ha. When all possible sources contributing to emissions of N2O (both measured and calculated from the non‐measured sources) were included, total annual emissions of 7.7 and 7.0 kg N2O‐N per hectare of grazed pasture in the control and stand‐off treatments, respectively, were estimated. These results suggest that the use of stand‐off pads as a management practice during the wet seasons can be effective at reducing N2O emissions from dairy farm systems.
The heteropolymolybdate family: structural relations, nomenclature scheme and new species

Abstract Type specimens of the molybdoarsenates betpakdalite, natrobetpakdalite and obradovicite and the molybdophosphates mendozavilite, paramendozavilite and melkovite, and similar material from other sources, have been examined in an effort to elucidate the relations among these phases, which we designate as the heteropolymolybdate family of minerals. Using electron microprobe analysis, X-ray powder diffraction and single-crystal X-ray diffraction with crystal structure determination where possible, it was found that natrobetpakdalite, mendozavilite and melkovite are isostructural with betpakdalite and that obradovicite has a closely related structure. The betpakdalite and obradovicite structure types are based on frameworks containing four-member clusters of edge-sharing MoO6 octahedra that link by sharing corners with other clusters, with Fe3+O6 octahedra and with PO4 or AsO4 tetrahedra (T). The structures differ in the linkages through the Fe3+O6 octahedra, which produce different but closely related framework configurations. The structures contain two types of non-framework cation sites, which are designated A and B. In general, there are two or more A sites partially occupied by disordered, generally larger cations that are coordinated to O atoms in the framework and to H2O molecules. The B site is occupied by a smaller cation that is octahedrally coordinated to H2O molecules. The general formula for minerals with either the betpakdalite or the obradovicite structure is: [A2(H2O)nB(H2O)6][Mo8T2Fe33+O30+7(OH)7-x], where x is the total charge of the cations in the A and B sites (+3 to +7) and n is variable, ideally 17 for arsenates and 15 for phosphates. The ideal total number of A cations is defined as 2 in the general formula, but varies from 1 to 3.8 in analysed samples. Dominant cations at the A site include K, Na and Ca and at the B site Na, Ca, Mg, Cu and Fe. The combinations that have been identified in this study define six new heteropolymolybdate species. A suffix-based nomenclature scheme is established for minerals of the betpakdalite, mendozavilite and obradovicite groups, with the following root names based on the structure types and the T-site cations: betpakdalite (T = As), mendozavilite (T = P) and obradovicite (T = As). Two suffixes of the form -AB, corresponding to the dominant cations in the two different types of non-framework cation sites complete the species name. The historical name melkovite is retained rather than introducing mendozavilite-CaCa. Our investigation of the paramendozavilite type specimen revealed no paramendozavilite, but an apparently closely related new mineral; however, another sample of paramendozavilite analysed had K > Na.
A Raman spectroscopic temperature study of NH3+ torsional motion as related to hydrogen bonding in the L‐alanine crystal

A Raman study of the NH3+ torsional mode in the amino acid L-alanine has been performed. The temperature dependence of this mode has been followed in the temperature region 110–350 K. The activation energy for NH3+ reorientation obtained from a linewidth vs temperature investigation, Ea = 3100±400 cm−1, is in excellent agreement with corresponding NMR results, thus demonstrating that Raman spectroscopy can serve as a complementary method to NMR in obtaining torsional barrier heights. Based on an X-ray investigation, crystal and hydrogen bond parameters have been calculated as a function of temperature. The increase of the NH3+ torsional barrier on going to lower temperatures is essentially attributed to the shortening of one specific hydrogen bond. The detection of the NH3+ torsional hot transition is important for the determination of the shape of the lower portion of the NH3+ torsional potential. The sixfold term V6 of the potential used, three-plus sixfold, is thus very sensitive to the frequency difference between the NH3+ torsional fundamental and hot band. The optimum frequency fit gives, however, too large a value for the barrier height V3. The reason for this is interpreted as arising from the severe distortion of the hydrogen bonds at large torsional angles. The results presented here support recent findings that a revision of the dynamic picture of the hydrogen bonds in L-alanine crystal, as reported in two earlier papers, is needed.
A new approach to measuring D/H ratios with the Cameca IMS‐7F

SIMS offers spatial resolution on the scale of micrometers and consumes an exceedingly small amount of sample. In addition, easy sample preparation, rapid analysis and high sensitivity allow SIMS to be applied to hydrous minerals. Hydrogen isotopes normally can be measured as negative or positive secondary ions using either a Cs+ or an O− primary ion beam, respectively. The hydrogen negative secondary ion yields are only marginally higher than hydrogen positive secondary ion yields. There are advantages and disadvantages to using either method to analyze hydrogen isotopes by SIMS. For insulating samples, O− is commonly used to avoid using the electron gun. The main disadvantage in using an O− beam is hydride interference (H2+) associated with deuterium (D) that must be resolved using a mass resolving power of ∼1000–2000. We have developed a method where we combine a lower mass resolution and a small voltage offset to obtain rapid (12 min), high‐precision (∼2‰, 2σ) D/H ratios in turquoise using a Cameca IMS‐7F ion microprobe. This technique can be applied to a variety of hydrous minerals in geological materials. Copyright © 2010 John Wiley & Sons, Ltd.
A Revised Analysis of the Effect of Surfactants on Two‐Phase Phenomena in Horizontal Air‐Water Pipe Flow

Flow regimes, hold-up and pressure loss measurements in two-phase air-water co-current horizontal flow have shown that the effect of surfactant was to: a. suppress the formation of ripples or gravity waves; b. progressively extend the range of the smooth stratified pattern at the expense of the ripple flow regime, as the gas rate was increased; c. increase the liquid hold-up above that for water alone over the wavy regimes from the top end of the smooth stratified pattern to the onset of film-plus-droplet flow, and there was a corresponding reduction in pressure loss. The mechanism responsible for the suppression of waves resulted in a reduction in the ability of the gas to scour out the liquid. The fundamental cause for these effects was linked to local variations in surface tension as the surface film on the liquid was alternatively expanded and compressed by the ripples. Additional effects of surfactant at other flow conditions were that: d. drag reductions occurred in the slug and plug regimes with the surfactant affecting the liquid slug nose regions; e. drag reduction also occurred in the annular regime at high gas and liquid flow rates, caused by the damping of waves at the base of the annular film. These results help explain a number of apparent anomalies presented in the literature.
Validation of forcefields in predicting the physical and thermophysical properties of emeraldine base polyaniline

We report a molecular modelling study to validate the forcefields [condensed-phase optimised molecular potentials for atomistic simulation studies (COMPASS) and polymer-consistent forcefield (PCFF)] in predicting the physical and thermophysical properties of polymers. This work comprises of two key steps: (1) generating and validating the molecular model in predicting the material properties of the bulk amorphous emeraldine base polyaniline and (2) modelling the glass–rubber transition of the polymer. From all the molecular dynamics simulation results, it clearly shows that the more recent COMPASS forcefield provides a higher accuracy in predicting the polymer properties than PCFF, and it enables a more accurate prediction of condensed-phase properties (density, glass transition temperature, solubility parameters, etc.) in a broad range of temperature for various applications.
Scaling Laws for the Swelling of Neutral and Charged Polymer Brushes in Good Solvents

We compare the swelling of surface-attached neutral poly(4-vinylpyridine) (PVP) and charged poly(N-methyl-4-vinylpyridinium iodide) (MePVP) brushes under good solvent conditions using multiple-angle null ellipsometry. The polymer layers were prepared by the “grafting from” technique, where a low molecular mass initiator is self-assembled on the substrate and the polymer brush is grown in situ by free radical chain polymerization. The positively charged MePVP brush was generated from a neutral PVP brush by a polymer-analogous quaternization reaction. As predicted by mean-field theory, the thickness of the neutral swollen brush (PVP) increases with graft density whereas the thickness of the highly charged polyelectrolyte (MePVP) brush in pure water (“salt-free”) is almost independent of the graft density.
Sweet basil (Ocimum basilicum L.) and potassium fertilization

ABSTRACT The objective of the present study was to examine the effect of potassium (K) fertilization and soil texture on total yield (1st and 2nd cuttings) and yield components of sweet basil (Ocimum basilicum L.) A greenhouse pot experiment was conducted in a completely randomized statistical design. Basil growth was examined in two different textured soils under three different doses of K fertilization. Generally, for the basil grown under clay soil conditions, moderate amounts of K fertilization is proposed to be sufficient if higher linalool contents are wanted. However, if the growing conditions are sandy loam in texture, it is suggested that higher doses of K be used. Results also highlighted the contribution of second cut as an important cultural practice in the cultivation of an annual basil.
A hierarchical method to integrated solvent and process design of physical CO2 absorption using the SAFT‐γ Mie approach

Molecular-level decisions are increasingly recognized as an integral part of process design. Finding the optimal process performance requires the integrated optimization of process and solvent chemical structure, leading to a challenging mixed-integer nonlinear programming (MINLP) problem. The formulation of such problems when using a group contribution version of the statistical associating fluid theory, SAFT-γ Mie, to predict the physical properties of the relevant mixtures reliably over process conditions is presented. To solve the challenging MINLP, a novel hierarchical methodology for integrated process and solvent design (hierarchical optimization) is presented. Reduced models of the process units are developed and used to generate a set of initial guesses for the MINLP solution. The methodology is applied to the design of a physical absorption process to separate carbon dioxide from methane, using a broad selection of ethers as the molecular design space. The solvents with best process performance are found to be poly(oxymethylene)dimethylethers. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3249–3269, 2015
Effects of aqueous extract of Ganoderma lucidum on blood glucose levels of normoglycemic and alloxan-induced diabetic wistar rats

Ganoderma lucidum mushroom has long been used as a potent medicinal plant in the far East, but its ethnomedicinal importance in Nigeria is yet to be fully realized. The effects of the aqueous extract on blood glucose levels of alloxan induced and normal Wistar rats have been investigated. Three doses of the extract (250, 500 and 1000 mg/Kg) were administered intraperitoneally. The dose of 250 mg/Kg of the extract did not significantly alter the blood glucose levels of both normal and alloxan induced diabetic Wistar rats. However, the doses of 500 and 1000 mg/Kg of the extract did significantly (p<0.05) decrease the blood glucose levels of alloxan diabetic Wistar rats at 4, 8 and 24 h. In normal rats, the dose of 1000 mg/Kg of the extract significantly (p<0.05) decrease the blood glucose levels at 8 and 24 h only. In conclusion, the dose of 1000 mg/Kg of the extract has shown both significant (p<0.05) hypoglycemic and anti-hyperglycemic effects in Wistar rats.
Absorção e Níveis Críticos de Fósforo na parte aérea para manutenção da produtividade do Capim-Elefante (Pennisetum purpureum cv. Napier)

The experiment was carried out in the field, during two years, to evaluate the phosphate fertilizing residual effect implantation over the phosphate absorption and critical levels in the plant for the elephant grass (Pennisetum purpureum Schum. cv. Napier) maintenance. The treatments were arranged according to the factorial 2 X 2 X 5, in blocks randomly lined with three repetitions, and consisted of two phosphate application ways (located in the bottom of the hole and distributed in the hole with incorporation), two spacing between the plantation lines (0,5 and 1,0 m) and five levels of phosphate correspond to the 0, 30, 60,100 and 150 kg/ha P doses and to 0, 60, 120, 200 and 300 kg/ha of the P2O5 to the applications localized and distributed, respectively. Seven plant harvesting were done from the plants in the parcel central hole (lines), corresponding to 2 m2. After weighing the harvested forage, samples were taken to determinate the dry matter content (DM) and the phosphate in the DM. After each cut, a dressing fertilization with potassium and nitrogen covering (67 kg/ha of N and K2O, using ammonium sulfate and potassium cloret). The highest phosphate content in the plant DM was observed when the fertilizer was distributed and incorporated to the plantation hole. The phosphate critical level in the plants DM presented an average level of 0.13 dag/kg, without great variations due to the application way and, or, to the spacing between the plantation lines.