Miracle-dz/UniFAR-FTUs huggingface dataset:
Theoretical studies of substituent effects on the additions of amines to carbonyl compounds: a relation among energetics, structures, and isotope effects

Etude par une methode d'orbitale moleculaire ab initio des reactions d'addition d'amines (NH 3 , CH 3 NH 2 et NHF 2 ) a des composes carbonyles (CH 2 O, CH 3 CHO et CF 2 O)
Physicochemical and Rheological Analysis of Flour Mill Streams

ABSTRACT Knowing the quality of mill streams is very important for obtaining standardized flours with intended qualities for specific applications. The physicochemical and rheological quality of wheat flour mill streams obtained through industrial milling were analyzed. Rheological behavior was tested using alveograph, rheofermentograph, and mixolab equipment. The results obtained indicate that the starch damage, protein quality, and rheological properties vary with the mill streams. Three variants of breadmaking flours, obtained by blending different milling fractions without negatively affecting the extraction and final product quality, were characterized.
Energy Dissipation at the Slug Nose and the Modeling of Solids Transport in Intermittent Flow

It is shown, by means of Lagrangian momentum and power balances across the slug nose in slug flow, that the power dissipated due to sudden expansion of the fluid in the film immediately downstream of the slug nose is greater than the power lost due to viscous action at the pipe wall but that it may not be large enough to materially aid particle transport. This has the implication that sand transport in intermittent flow may be considered as transport in a hybrid flow of hydraulic conveying and stratified flow when the length of the mixing section at the slug nose is short compared to the length of the slug body. On montre, au moyen de bilans de quantite de mouvement de Lagrange et d'emergoe dans le nez du bouchon d'un ecoulemnet piston, que l'energie dissipee du fait de l'expansion soudaine du fluide dans le film immediatement en aval du nez du bouchon, est plus grande que l'energie perdue du fait de l'action visqueuse a la paroi du tube, mais qu'elle peut ne pas etre suffisamment grande pour aider concretement le transport de particules. Cela implique que le transport de sable dans un ecoulement intermittent peut etre considere comme un transport dans un ecoulement hybride forme d'un convoyage hydraulique et d'un ecoulement stratifie lorsque la longueur de la section de melange au nez du bouchon est courte comparativement a la longueur du bouchon.
Dynamic Viscoelasticity of Wood After Various Drying Processes

In this study, specimens of heartwood from Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) plantation trees were dried by high-temperature drying (HTD), low-temperature drying (LTD), and freeze vacuum drying (FVD), respectively. The dynamic viscoelastic properties of dried and untreated wood specimens with various moisture contents were investigated in the temperature range between − 120 and 40°C at 1 Hz using a dynamic mechanical analysis (DMA). The results indicated that the relative storage modulus and relative loss modulus were both the highest for HTD wood and the lowest for FVD wood, and that two mechanical relaxation processes developed. The α relaxation process in the higher temperature range was presumably a result of surpassing the glass transition of hemicelluloses with low molecular weight, whereas the β relaxation process occurring in the lower temperature range was most probably due to the motions of both methyl groups in the amorphous region of wood cell wall and adsorbed water molecules in wood. As moisture content increased, the decrease of relative storage modulus with increasing temperature became more dramatic, and the loss peak temperatures of the relaxation processes shifted to lower temperature range. The difference of dynamic mechanical behavior among untreated and dried specimens reduced with the increase of moisture content.
Oxidative Degradation of Nadic-End-Capped Polyimides. 2; Evidence for Reactions Occurring at High Temperatures

The oxidative degradation of PMR (for olymerization of monomeric reactants) polyimides at elevated temperatures was followed by cross-polarized magic angle spinning (CP-MAS) NMR. 13C labeling of selected sites in the polymers allowed for direct observation of the transformations arising from oxidation processes. As opposed to model compound studies, the reactions were followed directly in the polymer. The labeling experiments confirm the previously reported oxidation of the methylene carbon to ketone in the methylenedianiline portion of the polymer chain. They also show the formation of two other oxidized species, acid and ester, from this same carbon. In addition, the technique provides the first evidence of the kind of degradation reactions that are occurring in the nadic end caps. Several PMR formulations containing moieties determined to be present after oxidation, as suggested by the labeling study, were synthesized. Weight loss, FTIR, and natural abundance NMR of these derivatives were followed duri.
Polarizabilities of carbon nanotubes: Importance of the crystalline orbitals relaxation in presence of an electric field.

The static polarizabilities of a series of zigzag single walled carbon nanotubes [(m, 0) with m ≠ 3n for m = 7–25] were computed by the coupled perturbed Kohn-Sham (CPKS) coupled method recently implemented in the periodic CRYSTAL code. This method makes it possible to compute both the longitudinal and transverse polarizabilities with the same approach including the local field depolarization effects for the whole series of the investigated nanotubes. To quantify these effects, the unscreened longitudinal and transverse polarizabilities were also calculated within the linear response theory using the Sum Over States (SOS) method. Our results confirmed the inverse-square dependence on the bandgap of the longitudinal polarizabilities which are found weakly affected by the crystalline orbital relaxation. On the other hand, the comparison between the screened (CPKS) and unscreened (Sum Over States) transverse polarizabilities permit to calibrate more precisely the classical correction of Benedict et al. (Phys Rev B, 1995, 52, 8541) which must be applied to include the local field effect at the SOS level. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Solubility of liquid CO2in water at temperatures from 278 K to 293 K and pressures from 6.44 MPa to 29.49 MPa and densities of the corresponding aqueous solutions

Abstract An experimental investigation is reported on the solubility of CO2(l) in water at temperatures from 278 K to 293 K and pressures from 6.44 MPa to 29.49 MPa and on the corresponding densities of the CO2aqueous solutions. Based on the experimental data, an expression for the Henry's law constant as a function of temperature and pressure was obtained. Good agreement was observed between the experimental data and the prediction made using the modified Henry's law and the resultant Henry's law constant, with a maximum difference of
Kristallographie der Alaune I

Observations on the morphology and polymorphism as well as new measurements of density (64), lattice constants (64), dielectric constants (25), elastic constants (50), thermal expansion coefficients (41) and thermoelastic constants (32) for various types of alums are given (the numbers of measurements are given in brackets). Simple criteria for the assignment to the types of the alums result from these measurements. The crystallophysical properties give indications of the structural differences between the types, which agree with previous structure determinations. The thermoelastic behaviour is closely connected to the polymorphism. Alums with asymmetric structural units show anomalies in many properties.
Effects of Electrode Materials and Annealing Ambients on the Electrical Properties of TiO2 Thin Films by Metalorganic Chemical Vapor Deposition

In this work, we investigate the effects of the top electrode materials and annealing ambients on the electrical properties of chemical-vapor-deposited (CVD) TiO2 films. Experimental results indicate that the leakage current is mainly determined by the work function of electrode materials before sintering. The capacitor with TaN top electrode reveals the least leakage. After 450° C and 800° C sintering in N2, owing to its thermal stability, WN is found to be the optimal material for withstanding high-temperature thermal treatment. From the annealing ambient results, N2O was more effective than O2 in reducing leakage current, and furnace annealing in N2O ( FN2O) produces the smallest leakage. Such a phenomenon is primarily owing to the reduction of oxygen vacancies and carbon concentration in TiO2 by the atomic oxygen generated by the dissociation of N2O during the thermal cycle, thereby improving film quality.
The vibrational spectra of titanium tetrachloride–hydrochloric acid and titanium tetrachloride–tri-n-butyl phosphate systems and the hexachloro-anions of zirconium(IV), hafnium(IV), niobium(V), and tantalum(V)

The Raman spectra of solutions of titanium tetrachloride in hydrochloric acid have been reinvestigated. These solutions probably contain oxyhalide species of the type [TiO2Cl4]4– or [TiOCl5]3– and not [TiCl6]2– as was thought previously. Raman-spectroscopic studies of the titanium tetrachloride–tri-n-butyl phosphate (TBP) system show that both a 1 : 1 complex of symmetry C2v, and a 1 : 2 complex, TiCl4,2TBP (probably cis, of symmetry C2v) are formed. The Raman spectra of solutions of the tetrachlorides of zirconium(IV) and of hafnium(IV) in hydrochloric acid show that the hexachloro-anions are present in these solutions. The vibrational spectra of NbCl6– and TaCl6– were obtained by studying the Raman spectra of solutions of the tetraethylammonium salts in acetonitrile and nitromethane respectively.
EXAFS study on the neptunium(V) complexation by various humic acids under neutral pH conditions

Abstract The structure of Np(V) humic acid (HA) complexes at pH 7 was studied by extended X-ray absorption fine structure analysis (EXAFS). For the first time, the influence of phenolic OH groups on the complexation of HA and Np(V) in the neutral pH range was investigated using modified HAs with blocked phenolic OH groups and Bio-Rex70, a cation exchange resin having only carboxyl groups as proton exchanging sites. The formation of Np(V) humate complexes was verified by near-infrared (NIR) spectroscopy. Axial Np-O bond distances of 1.84–1.85 Å were determined for the studied Np(V) humate complexes and the Np(V)-Bio-Rex70 sorbate. In the equatorial plane Np(V) is surrounded by about 3 oxygen atoms with bond lengths of 2.48–2.49 Å. The comparison of the structural parameters of the Np(V) humates with those of Np(V)-Bio-Rex70 points to the fact that the interaction between HA and Np(V) in the neutral pH range is dominated by carboxylate groups. However, up to now a contribution of phenolic OH groups to the interaction process cannot be excluded completely. The comparison of the obtained structural data for the Np(V) humates to those of Np(V) carboxylates and Np(V) aquo ions reported in the literature indicates that humic acid carboxylate groups predominantly act as monodentate ligands. A differentiation between equatorial coordinated carboxylate groups and water molecules using EXAFS spectroscopy is impossible.
Critical Exponents of Photoinitiated Gelation at Different Light Intensities

A photo-differential scanning calorimetric (Photo-DSC) technique was used to study the photoinitiated radical polymerization of a 75% epoxy diacrylate (EA) and 25% tripropyleneglycoldiacrylate (TPGDA) mixture with 2-mercaptothioxanthone (TX-SH) as photoinitiator by using different light intensities. Photopolymerization reactions were carried out under identical conditions of temperature and initiator concentration. It was observed that all conversion curves during gelation at various UV light intensities present good sigmoidal behavior as predicted by the percolation model. Observations around the critical time, called the glass transition point (tg), taken for polymerization to reach the maximum rate (Rp max) show that the gel fraction exponents β obeyed the universal percolation picture. On the other hand, Rp max, t g, and final conversion values were found to be dependent on the UV light intensity.
EFFECT OF PREVIOUS NITROGEN STARVATION ON NO3 − AND NH4 + UPTAKE AND ASSIMILATION ASSOCIATED WITH THE ENDOGENOUS SOLUBLE CARBOHYDRATE UTILIZATION IN MOROCCAN WHEAT SEEDLINGS

Uptake of the two forms of nitrogen NO3 − and NH4 + and nitrate reduction have been studied in two varieties of Moroccan wheat seedlings, cvs. Sais and Jouda, cultivated under controlled conditions in a hydroponic medium. The available form of nitrogen in the medium had a direct effect on the rate of nitrogen absorption. A brief nitrogen starvation increased the root length and stimulated accumulation of soluble carbohydrates, especially in the root tissues. A resupply of nitrogen stimulated ammonium and nitrate uptake and assimilation with higher mobilization of the soluble carbohydrates previously accumulated in root seedlings. It is suggested that root nitrogen and carbohydrate status might both regulate nitrate uptake and reduction in Moroccan wheat seedlings. The seedlings raised with the nitrate supply accumulated nitrate in the vacuole as an osmoticum. Shoots are the preferential site for such accumulation. The accumulation of mineral nitrogen was absent in the seedlings cultivated with ammonium supply but was compensated by accumulation of soluble organic nitrogen.
Heterogeneous reactions in sulfuric acid aerosols: A framework for model calculations

A framework for applying rates of heterogeneous chemical reactions measured in the laboratory to small sulfuric acid aerosols found in the stratosphere is presented. The procedure for calculating the applicable reactive uptake coefficients using laboratory-measured parameters is developed, the necessary laboratory-measured quantities are discussed, and a set of equations for use in models are presented. This approach is demonstrated to be essential for obtaining uptake coefficients for the HOCl + HCl and ClONO2 + HCl reactions applicable to the stratosphere. In these cases the laboratory-measured uptake coefficients have to be substantially corrected for the small size of the atmospheric aerosol droplets. The measured uptake coefficients for N2O5 + H2O and ClONO2 + H2O as well as those for other heterogeneous reactions are discussed in the context of this model. Finally, the derived uptake coefficients were incorporated in a two-dimensional dynamical and photochemical model thus for the first time the HCl reactions in sulfuric acid have been included. Substantial direct chlorine activation and consequent ozone destruction is shown to occur due to heterogeneous reactions involving HCl for volcanically perturbed aerosol conditions at high latitudes. Smaller but significant chlorine activation also is predicted for background aerosol loadings at extreme high latitudes, suggesting chlorine activation can occur on background sulfuric acid aerosol in these regions. The coupling between homogeneous and heterogeneous chemistry is shown to lead to important changes in the concentrations of various reactive species. The basic physical and chemical quantities needed to better constrain the model input parameters are identified.
Development of Ann-Based Models to Predict Biogas and Methane Productions in Anaerobic Treatment of Molasses Wastewater

Two three-layer artificial neural network (ANN) models were respectively developed to predict biogas and methane production rates in a pilot-scale mesophilic up-flow anaerobic sludge blanket (UASB) reactor treating molasses wastewater. Eight process-related variables such as volumetric organic loading rate (OLR), influent and effluent pH, operating temperature, influent and effluent alkalinity, effluent chemical oxygen demand (COD), and volatile fatty acid (VFA) concentrations were selected for the implementation of an artificial intelligence-based approach. A tangent sigmoid transfer function (tansig) at the hidden layer and a linear transfer function (purelin) at the output layer were conducted for the proposed ANN models. Several benchmark comparisons were conducted to obtain an optimal algorithm for training the network. After backpropagation training combined with principal component analysis (PCA), the scaled conjugate gradient algorithm (trainscg) was found as the best of the 11 training algorithms. The number of neurons in the hidden layer was optimized as nine and 12 with the minimum mean squared errors (MSE) of 0.06238 and 0.06488, respectively, for the estimation of biogas and methane production rates. ANN-predicted results were also compared to the outputs of two non-linear regression models by means of several statistical indicators, such as determination coefficient (R2), unsystematic root mean-square error (RMSEU), index of agreement (IA), and fractional variance (FV). Computational results clearly demonstrated that, compared to the conventional multiple regression-based methodology, the proposed ANN-based models produced smaller deviations and exhibited superior predictive accuracy with satisfactory determination coefficients of about 0.935 and 0.924, respectively, for the forecasts of biogas and methane production rates.
Influence of vegetable and mineral oils on the efficacy of some post-emergence herbicides for grass weed control in wheat

Two field experiments in central Italy on wheat showed that the application rate of clodinafop-propargyl could be significantly reduced to 1/2 of the labelled rate to control oats and canarygrass, with no loss in weed control efficacy. This reduction was favoured by the use of mineral or vegetable oil, with no apparent differences. No rate reduction of clodinafop-propargyl was possible for ryegrass, which needed at least the labelled rate plus vegetable or mineral oil to be satisfactorily controlled. A mixture of diclofop-methyl+fenoxaprop-p-ethyl could be effectively used only against oats controlled at 2/3 of the labelled rate. This mixture did not prove effective against canarygrass, while it was effective against ryegrass only when applied at the maximum labelled rate mixed with vegetable or mineral oil.
Effect of Air Pressure upon Spray Angle/Width Characteristics of Simplex Pressure Swirl Atomizers

This paper examines the spatial distribution characteristics of fuel sprays emanating from simplex pressure swirl atomizers of the type commonly used in the gas turbine engine. Three different atomizers were tested on kerosine at chamber gas pressures up to 1377 KN/m2 and fuel pressure drops up to 3448 KN/m2. A non-intrusive, still photographic technique was developed for recording the spray profiles over the entire range of test conditions. Analysis of the experimental data shows that the closing in of the spray boundaries due to an increase in air pressure is a result of the aerodynamic interaction between the fuel spray and its gaseous environment — the nozzle hydrodynamics apparently exercising no influence. Experimental data collected in the study reveals the influence of gas pressure (Pa) upon the half width (y) of the spray envelope at a downstream distance of 30mm from the nozzle face to be described adequately by the expression y α Display FormulaPa-0.26. Copyright © 1986 by ASME
Orientation Controllable Growth of MoO3 Nanoflakes: Micro-Raman, Field Emission, and Birefringence Properties

A simple but effective way to control the orientational arrangement of MoO3 nanoflakes is presented, which offers an opportunity to investigate the anisotropic properties of different crystallographic faces. Their electrical and optical properties are investigated. According to the polarized micro-Raman spectra, oxygen vacancies preferred to be located at the sharp side edges of the lamella, which might play an important role in the catalytic properties of samples. Ascribing to the unique structural geometry and the oxygen-defects-induced reduction of the work function, the electron field emission properties of the samples show that the erect MoO3 nanoflakes are potential candidates for the cold-cathode-based electronics. Furthermore, strong optical birefringence properties of samples are also first observed.
Optimal-Suboptimal Synthesis and Design of Flotation Circuits

The integrated approach of process synthesis and design has been applied to determine the optimal-suboptimal configuration and design parameters of a flotation circuit for separation of mineral species. Mean residence time of parti-culate species in each cell is the design parameter to be optimized, which along with the optimal structure is extracted simultaneously from a generalized circuit by direct search. The validity of the method has been demonstrated by comparing results obtained by using this method with real optimal structure and parameter values obtained by optimizing all feasible structures, enumerated one at a time, for the case of a two cell circuit using two different objective functions of recovery, grade, and profit. The method is then extended to more realistic four cell circuit and feed comprising valuable mineral, gangue, and middlings.
In situ measurements of electrode work functions in free-burning arcs during operation at atmospheric pressure

A method of in situ measurement of electrode work functions in free-burning argon arcs during operation is presented. This technique is based on the photoelectric effect ocurring at the surface of a tungsten cathode with the use of a pulse laser system consisting of a Nd–YAG laser and a dye laser. Three types of tungsten electrode, namely, pure W, W–2% ThO2 and W–2% La2O3 are used in this work. Free-burning arcs are operated in argon at atmospheric pressure at currents of 100 A and 200 A. The effective work functions of pure W, W–2% ThO2 and W–2% La2O3 electrodes during operation at a current of 200 A are found to be, respectively, 4.6, 2.8 and 3.0 eV from in situ measurements. These results are very close to the work functions of pure W, ThO2 and La2O3 obtained from the literature. The in situ measurements, however, show that the effective work functions of pure W, W–2% ThO2 and W–2% La2O3 electrodes for an 100 A arc are, respectively, 2.9 eV, 2.6 eV and 2.0 eV. It is shown that each effective work function for an 100 A arc clearly becomes lower than that for a 200 A arc for all types of tungsten electrodes.
Off‐lattice Monte Carlo simulation of dilute and concentrated polymer solutions under theta conditions

A recently introduced bead‐spring type model of polymer chains with purely repulsive interactions between the beads is modified to allow for attractive forces at intermediate distances. This new model is suitable for the study of thermal properties of three‐dimensional polymer solutions and melts and can be efficiently simulated with Link–Cell Monte Carlo methods. As a first step, the single chain lengths up to N=128 beads are studied and the theta temperature θ is located. It is shown that the data are compatible with the theoretically predicted crossover scaling behavior, and that the properties of collapsed chains can be studied for reasonably low temperatures T<θ. In addition to static properties (chain radii, polymer density inside the coil, internal energy, specific heat) also dynamic properties are obtained, namely various mean square displacements and relaxation times and the self diffusion constant. While for T=θ (and long enough chains), there is reasonable agreement with the Rouse model, a diff.