Miracle-dz/UniFAR-FTUs huggingface dataset:
Aplicação de fosfato natural e reciclagem de fósforo por milheto, braquiária, milho e soja

The objective of this experiment was to compare the ability of soybean (Glycine max), corn (Zea mays), Brachiaria brizantha cv. Marandu and pearl millet (Pennisetum glaucum) for P-uptake, at different levels of the Alvorada natural rock phosphate, under controlled conditions. The soil used was a dystrophic Hapludalf (180 g kg-1 clay), which was limed and fertilized with N, K and micronutrients. The crops were grown in 18 dm3 pots for 50 days in a greenhouse, at different P2O5 rates (0, 100, 200, and 400 kg ha-1). The amount of rock phosphate was calculated based on the total P2O5 content. Contrasting to soybean, there was a positive response of maize to higher P2O5 doses. The dry matter production by Brachiaria brizantha cv. Marandu was lower than that observed for pearl millet, but it still was highly efficient in P uptake despite the low solubility of the rock phosphate. Pearl millet is an important cover crop because of the high dry matter production and the capacity for recycling P in a relatively short period (50 days).
Bonding and stabilities of small silicon clusters: A theoretical study of Si7–Si10

Ab initio calculations have been performed to study the structures and energies of intermediate‐sized silicon clusters (Sin, n=7–10). All geometries have been optimized at the Hartree–Fock (HF) level of theory with the polarized 6‐31G* basis set. The harmonic vibrational frequencies have been evaluated at the HF/6‐31G* level of theory. Electron correlation effects have been included by means of fourth order Mo/ller–Plesset perturbation theory. The most stable structure for Si7 is a pentagonal bipyramid and the lowest energy calculated structures for Si8–Si10 correspond to capped octahedral or prismatic geometrical arrangements. The evolution of the cluster geometries with increasing size is discussed. Clusters containing four, six, seven, and ten atoms have been identified as ‘‘magic numbers’’ for small silicon clusters, both theoretically and experimentally. The hybridization and bonding in small silicon clusters is discussed. Our results are used to interpret the recent photoelectron spectra of negative.
Neutron diffraction study on structural and magnetic properties of La2NiO4

An overall survey of the structural and magnetic features of the La2NiO4+ delta system is presented as a result of neutron diffraction experiments. The stoichiometric compound ( delta =0) presents two structural phase transitions. At T0 approximately=770 K, La2NiO4 transforms from tetragonal (I4/mmm) to orthorhombic (Bmab); at T1 approximately=80 K, from orthorhombic to a new tetragonal (P42/ncm) phase. Associated with this second phase transition a strong microstrain produces anisotropic broadening of Bragg reflections. La2NiO4 is three-dimensional (3D) antiferromagnetically ordered at room temperature (TN=330 K). A weak ferromagnetic component appears below T1. Oxygen excess suppress the 3D magnetic ordering and the structural phase transformations, giving rise to a non-stoichiometric compound with interstitial oxygens. A tentative phase diagram is proposed.
μ-XANES and μ-XRF Investigations of Metal Binding Mechanisms in Biosolids

Micro-X-ray fluorescence (micro-XRF) microprobe analysis and micro-X-ray absorption near-edge structure (micro-XANES) spectroscopy were employed to identify Fe and Mn phases and their association with selected metals in two biosolids (limed composted [LC] and Nu-Earth) before and after treatment to remove organic carbon (OC). Spatial correlations derived from elemental mapping of XRF images showed strong correlations between Fe and Cd, Cr, Pb, or Zn (r2= 0.65-0.92) before and after removal of most of the OC. The strong correlation between Fe and Cu that was present in intact samples disappeared after OC removal, suggesting that Cu was associated with OC coatings that may have been present on Fe compounds. Except for Fe and Cr, the spatial correlations of metals with Mn were improved after treatment to remove OC, indicating that the treatment may have altered more than the OC in the system. The Fe micro-XANES spectra of the intact biosolids sample showed that every point had varying mixtures of Fe(II and III) species and no two points were identical. The lack of uniformity in Fe species in the biosolids sample illustrates the complexity of the materials and the difficulty of studying biosolids using conventional analytical tools or chemical extraction techniques. Still, these microscopic observations provide independent information supporting the previous laboratory and field hypothesis that Fe compounds play a major role in retention of environmentally important trace elements in biosolids. This could be due to co-precipitation of the metals with Fe, adsorption of metals by Fe compounds, or a combination of both mechanisms.
ANTI-MICROBIAL, ANTI-BROWNING AND ANTI-MYCOTOXIGENIC ACTIVITIES OF SOME ESSENTIAL OIL EXTRACTS IN APPLE JUICE

Five essential oils (EO) extracted from lemon grass (Cymbopogon citratus), basil (Ocimum basilicum), rosemary (Rosmarimus officinalis), sage (Salvia officinalis), and clove (Eugenia aromatica), were investigated for their inhibitory effect against polyphenoloxidase (PPO) enzymatic browning, microbial activity, as well as effect on food spoilage and mycotoxin producing fungi, Aspergillus flavus and Aspergillus dchraceus. The TLC technique was used to determine the inhibitory effect of each EO on the radial growth of the fungus, and a dose response of the EO was recorded. Results showed that the EO from lemon grass, clove and rosemary were the most effective and prevented the growth and mycotoxin formation of the two fungi on apple juice when applied at doses of 0.05, 0.2 and 0.3%, respectively. Moderate activity was observed for the EO from basil dose between 0.2% and 0.3%, while the EO from sage was less inhibitory. These effects against food spoilage and mycotoxin producing fungi indicated each essential oil to be a potential food preservative. Also, the results showed that apple juices treated with essential oil (EO) extract from lemon grass, clove and rosemary had a positive effect towards the inhibition of PPO activity and reducing browning as compared to untreated, basil and sage treated juices, at room temperature (25°C) and at refrigerator (4°C), then increased shelf life of apple juice up to 4 weeks. The lowest microbial count for 4 weeks of storage period at 4°C was observed during the pretreatment of apple juice with lemon grass, clove and rosemary extracts. Therefore lemon grass, clove and rosemary extracts used in the study proved to be efficient extractives against food spoilage and mycotoxin producing fungi and in reducing both the enzymatic browning (PPO) and microbial counts during the preservation of apple juice by refrigeration at 4°C, indicating the potential applicability of each essential oil as a food preservative.
Item Design Considerations for Computer-Based Testing of Student Learning in Chemistry

The focus of this paper is an examination of how chemistry test items may be designed for use in a computer-testing environment. It begins by examining ideas from cognitive psychology and research on problem solving in chemistry. It also consider previous ways computers have been used to measure student learning in chemistry. The paper ends by providing a framework for developing test items (and examples of items) across macroscopic, particulate, symbolic and integrated levels of chemical understanding.
Comparison of shear flow of hexadecane in a confined geometry and in bulk

We examine the shear flow of hexadecane confined between plates with separation of 1–10 nm using molecular dynamics simulations. We also performed non-equilibrium molecular dynamics (NEMD) simulations of bulk hexadecane to compare with the simulations in the confined geometry. The stiffness of hexadecane and its high melting temperature result in a tendency to crystallize at room temperature or large load. We find that when confined between hydrocarbon walls, shearing hexadecane exhibits a velocity profile with substantial slip at the wall and essentially constant velocity over most of the interior space between the walls. As the strength of the wall-fluid interaction increases the amount of slip decreases, but slip always occurs at the boundary for the range of parameters studied. The results are compared with recent surface force apparatus experiments on hexadecane and with similar simulations of model bead-spring fluids.
Distribution of dissolved CO/sub 2/ in the Red Sea and correlations with other geochemical tracers

The concentration of dissolved inorganic carbon in the Red Sea was studied using the following model: TCO/sub 2/ = TCO/sub 2/o + . delta.TCO/sub 2/bio + . delta.TCO/sub 2/ant. The conservative part TCO/sub 2/o was correlated with the potential temperature T. The term . delta.TCO/sub 2/bio represents the exchanges with the marine biosphere and was expressed in the form a.delta. X + b.delta. Y with X = O/sub 2/, NO/sub 3/, PO/sub 4/ and Y = TA, Ca. The term . delta.TCO/sub 2/ant represents the excess of TCO/sub 2/ due to the penetration of human induced CO/sub 2/ in the ocean, which was expressed in the form co exp(-(z - zo)/H). As a result of the study, the contribution of each of the three identified signals was evaluated and the ratio C/O/N/P for the Red Sea basin was determined.
Tuning the Size of Gold Nanoparticles with Repetitive Oxidation-reduction Cycles

A simple method to control the size of gold nanoparticles (AuNP) using repetitive oxidation-reduction cycles is described. First, AuNP are shown to be readily immobilized onto an indium-doped tin oxide coated glass surface using cyclic voltammetry nanoparticle containing citrate buffer. Subsequently, the attached AuNPsize can be reduced to a desired level by potential cyclingin the range from 0 V to +1.1 V (vs. Ag/AgCl). Gradual AuNPdiameter decrease was attributed to the formation of gold oxide upon anodic potential sweep and the partial solubilization of the Au(III) species during subsequent reduction of gold oxide in the absence of gold chelator (e.g.,Cl-, Br-, or CN-) normally necessary for anodic gold dissolution.
Electrochemical Behavior of Carvedilol and Its Adsorptive Stripping Determination in Dosage Forms and Biological Fluids

Carvedilol is used in the management of hypertension and angina pectoris and as an adjunct to standard therapy in symptomatic heart failure. The electrochemical oxidation of carvedilol was investigated using cyclic, linear sweep voltammetry at a glassy carbon electrode. In cyclic voltammetry, in all values of pH, the compound shows two irreversible oxidation peaks. These two peaks are related to the different electroactive part of the molecule. First and second peak currents were found as diffusion and adsorption controlled, respectively. Using second oxidation step, two voltammetric methods were described for the determination of carvedilol by differential pulse adsorptive stripping voltammetry (AdSDPV) and square-wave adsorptive stripping voltammetry (AdSSWV) at a glassy carbon electrode. Accumulation of carvedilol was found to be optimized in 0.2 M H2SO4 solution following 275 second accumulation time at open circuit condition. Under optimized conditions, the current showed a linear dependence with concentration in the range between 2×10−7 M and 2×10−5 M in supporting electrolyte and in the range between 2×10−7 M and 1×10−5 M in spiked human serum samples for both methods. These methods were successfully applied for the analysis of carvedilol pharmaceutical dosage forms and spiked human serum samples. The repeatability and reproducibility of the methods for all media were determined. Precision and accuracy were also found. No electroactive interferences from the tablet excipients and endogenous substances from biological material were found.
Superconductivity of layered β-HfNCl with varying electron-doping concentrations and interlayer spacings

Layered β-HfNCl was electron-doped by the intercalation of alkaline earth metals AE (AE = Ca, Sr, Ba) using liquid ammonia solutions. The metals are cointercalated with ammonia, and the intercalation compounds AEx(NH3)yHfNCl have basal spacings almost constant at ∼12 Å, irrespective of the kind of AE used. The divalent AE concentration was widely varied over a range of x = 0.09–0.40, corresponding to an electron-doping concentration of twice as much as this value. The intercalation compounds become superconductors. The transition temperature Tc is almost constant at 23–24 K over the wide range of x with different kinds of AE. The superconductor is not yet over-doped at x = 0.4. The basal spacing d of the intercalated compound is further increased up to ∼19 Å by swelling with voluminous tetrahydrofuran (THF) and propylene carbonate (PC) molecules. The highest Tc of 26.0 K was obtained on the Ca and THF cointercalated compound Ca0.11(THF)yHfNCl (d = 15.0 Å), a new record of Tc in the electron-doped metal nitride chloride system.
BIOSORPTION OF METAL IONS USING CHITOSAN, CHITIN, AND BIOMASS OF RHIZOPUS ORYZAE

The biosorptive capacity of dried biomass fungus Rhizopus oryzae Went & Prinsen-Geerlings for metal sorption was compared with commercially available sources of chitin, chitosan and chitosan cross-linked with benzoquinone. Initial pH of the metal solution significantly influenced metal uptake capacity. The optimum biomass/solution ratio for metal uptake in all systems was 1 g/L. The highest metal uptake values (137, 108, 58, and 124 mg/g, respectively, for copper, zinc, arsenic, and chromium) were achieved with chitosan (1 g/L, at pH 4) from initial metal concentrations of 400 mg/L. Decreases in mean metal concentrations from a simulated copper/zinc mine effluent were 73%, 14%, and 36% for copper, aluminum, and zinc, respectively, which corresponded to respective metal uptake values of 16, 11, and 21 mg/g. Sorption from a simulated gold mine effluent showed decreases in mean concentrations of aluminum, arsenic, and copper of 85%, 30%, and 92%, respectively, which corresponded to respective metal uptake values of 3.0, 6.0, and 1.6 mg/g. The observed decreases in copper levels to concentrations below 1 mg/L indicate potential for specific polishing applications. At low pH, R oryzae biomass was more resistant than was chitosan. Cross-linking with benzoquinone under alkaline conditions conferred stability to the chitosan biomass under low pH, but some reduction in sorption capacity was observed.
Difference in formation of hydrogen and helium clusters in tungsten

The experimentally observed large difference in the depths of hydrogen and helium clusters formed in tungsten still lacks a fundamental explanation. Using density functional theory calculations, molecular dynamics simulations, and kinetic Monte Carlo calculations, we show that the fundamental mechanism behind the different clustering depths is significantly different behaviors of interstitial H and He atoms in W: H–H states are unstable for small interatomic distances whereas He–He states are strongly bound.
Using the WIBS-4 (Waveband Integrated Bioaerosol Sensor) Technique for the On-Line Detection of Pollen Grains

Primary biological aerosol particles (PBAP) such as pollen and fungal spores can induce allergenic responses and affect health in general. Conditions such as allergic rhinitis (hay fever) and asthma have been related to pollen concentrations. Likewise some pollen have been shown to induce ice nucleation and cloud condensation at higher temperatures than those associated with some chemical species, thereby affecting planet Earth's albedo and overall radiative balance. Hence, the near real-time (on-line) monitoring of airborne pollen and other PBAP using a variety of spectroscopic and light scattering techniques represents an area of growing development and consequence. In this study, two separate field campaigns (one at a rural site in Ireland and the other at an urbanized location in Germany) were performed to detect and quantify pollen releases using a novel on-line fluorescence spectrometer (WIBS-4). The results were compared with results obtained using more traditional Hirst-type impactors. Size, “shape,” and fluorescence characteristics of ambient particles were used to determine the concentrations and identity of the PBAP likely to be pollen grains. The concentration results obtained for both methodologies at both the Irish and German sites correlated very well, with R 2 values >0.9 determined for both campaigns. Furthermore, the sizing data available from the WIBS-4 approach employed in Ireland indicated that pollen grains can be identified in appropriate conditions. WIBS-4 measurements of Yew pollen both in the laboratory and at the rural site indicated almost identical size ranges of 25 to 27 μm. Yew pollen is generally reported to be in this range, but the measurements reported here are the first of their type providing data on the size of in-flight Yew pollen. Copyright 2014 American Association for Aerosol Research
Surface Characterization of Vulcanized Rubber Treated with Sulfuric Acid and its Adhesion to Polyurethane Adhesive

Abstract Modifications produced on a vulcanized styrene –butadiene rubber surface by treatment with sulfuric acid were studied and several experimental variables were considered. The treatment of R1 rubber with sulfuric acid produced a noticeable decrease in contact angle which was mainly ascribed to an increase in surface energy due to the formation of sulfonic acid moieties and C˭O bonds, and the removal of zinc stearate. The rubber surface swelled and became brittle as a result of the treatment, and when flexed microcracks were created. A rubber surface layer modification was produced with a consequent decrease in tensile strength and elongation-at-break values. The treatment enhanced the T-peel strength of R1 rubber/polyurethane adhesive joints and the locus of failure was cohesive in the rubber. The optimum immersion time in H2SO4 solution was less than 1 min., and the reaction time in air was not found to be critical; the neutralization with ammonium hydroxide and the high concentration of the sulfuric acid (95 wt%) were essential to produce adequate effectiveness of the treatment.
Residual ozone determination by flow injection analysis

It has been proposed that ozone be used to replace free chlorine for the disinfection of drinking water and waste water. For the use of ozone in this capacity, it would be necessary to have a fast accurate and precise method to analyze for the presence of residuals. An automated method for ozone determination based on the indigo reagent method is presented. This method is based on the advantages of flow injection analysis (FIA) techniques. 19 references, 3 tables, 2 figures.
THEORETICAL WAVELENGTHS AND TRANSITION PROBABILITIES FOR THE 3d9–3d84p AND 3d84s–3d84p TRANSITION ARRAYS IN Ni II

Abstract A complete tabulation of theoretical electric-dipole (E1) emission lines is presented for transitions between the 3d9–3d84p and the 3d84s–3d84p configurations of Ni II. For these configurations with an open d shell, we applied extensive multiconfiguration Dirac–Fock wave functions to compute excitation energies, transition probabilities, and lifetimes. Our ab initio data will be compared with available measurements and other calculations, where the overall agreement is seen to be satisfactory. Experimental data are still very scarce for these two transition arrays. Therefore, the present data set not only supports the evaluation of the currently available data base, but may also help to identify or calibrate additional (less intense and intercombination) lines in the low-lying spectrum of Ni II.
Rapid Determination of Heartwood Extractives in Larix sp. by Means of Fourier Transform near Infrared Spectroscopy

The feasibility of Fourier transform near infrared (FT-NIR) spectroscopy to rapidly determine extractive and phenolic content in heartwood of larch trees (Larix decidua MILL., L. leptolepis (LAMB.) CARR. and the hybrid L. x eurolepis) was investigated. FT-NIR spectra were collected from wood powder and solid wood using a fibre-optic probe. Partial Least Squares (PLS) regression analyses were carried out describing relationships between the data sets of wet laboratory chemical data and the FT-NIR spectra. Besides cross and test set validation the established models were subjected to a further evaluation step by means of additional wood samples with unknown extractive content. Extractive and phenol contents of these additional samples were predicted and outliers detected through Mahalanobis distance calculations. Models based on the whole spectral range and without data pre-processing performed well in cross-validation and test set validation, but failed in the evaluation test, which is based on spectral outlier detection. But selection of data pre-processing methods and manual as well as automatic restriction of wavenumber ranges considerably improved the model predictability. High coefficients of determination (R2) and low root mean square errors of cross-validation (RMSECV) were obtained for hot water extractives (R2 = 0.96, RMSECV = 0.86%, range = 4.9–20.4%), acetone extractives (R2 = 0.86, RMSECV = 0.32%, range = 0.8–3.6%) and phenolic substances (R2 = 0.98, RMSECV = 0.21%, range = 0.7–4.9%) from wood powder. The models derived from wood powder spectra were more precise than those obtained from solid wood strips. Overall, NIR spectroscopy has proven to be an easy to facilitate, reliable, accurate and fast method for non-destructive wood extractive determination.
Elastic Properties of Metals and Alloys, I. Iron, Nickel, and Iron-Nickel Alloys

A comprehensive compilation is given of elastic properties of iron‐nickel alloys. When sufficient data exist, preferred values are recommended. This compilation covers, besides pure iron and pure nickel, the entire binary composition range, both b.c.c. and f.c. c. phases. Elastic constants included are: Young's modulus, shear modulus, bulk modulus (reciprocal compressibility), Poisson's ratio, and single‐crystal elastic stiffnesses, both second‐order and higher‐order. Data are compiled for variation of elastic constants with composition, temperature, pressure, magnetic field, mechanical deformation, annealing, and crystallographic transitions. An overview is given from the vantage points of the electron theory of metals, elasticity theory, and crystallographic theory. Also included are discussions of iso‐thermal and adiabatic elastic constants, interrelationships among engineering elastic constants, computation of the latter from single‐crystal elastic stiffnesses, and similar topics. Where key data have n.
Moisture-resistant ZnO transparent conductive films with Ga heavy doping

Moisture-resistant ZnO transparent conductive films were formed with Ga heavy doping by off-axis-type rf magnetron sputtering. The resistivity of 12.4wt% Ga-doped ZnO is 1.3×10−3Ωcm and changes by less than 3% over a 2000h reliability test at a temperature of 85°C and a humidity of 85%. The crystal structural analysis of the heavily Ga-doped ZnO films indicates that the c axis grows along various directions, which is quite different from the conventional c-axis oriented growth. The effect of heavy doping is discussed based on the crystal structural transformation and carrier compensation by excess Ga segregated in the film.