Miracle-dz/UniFAR-FTUs huggingface dataset:
Solvation: Effects of molecular size and shape

Sharp et al. have raised the question: If a solute and its solvent have different molecular sizes, how should solvation interaction energies be extracted from transfer experiments? Is the chemical potential more appropriately given by ‘‘classical’’ solution theory or by Flory–Huggins theory? We study a general statistical mechanical treatment of solvation, a generalized Flory–Huggins theory, and related treatments by Hildebrand and by Sharp et al. to determine the physical basis for size‐dependent terms in the chemical potential, and their limitations and applicabilities. We find that the extra entropy in the Flory–Huggins theory does not arise from the disparity of sizes of solute and solvent, from free volume, or from artifacts of approximations. Rather, when solutes and solvents have sufficient complexity that they can ‘‘interfere’’ with each other in solution, there is an ‘‘entropy of coupling’’ of translational freedom to excluded volume or internal or rotational degrees of freedom. The Flory–Huggins.
A technique for measuring contact angles at particles

The behavior of particles at the phase transition between a gas or liquid and another liquid phase may be characterized by the so-called wetting (or contact) angle. In contrast to plane surfaces, which allow such measurements to be conducted relatively easily, the determination of the wetting angle between a liquid and the surfaces of fine particles demands extensive preparative measures. The method adopted by Heertjes and Kossen [12] for example, involves compressing a tablet from the powder in question, from which the wetting angle may then be derived. The compression process naturally modifies the superficial structure of the particles, and hence their wetting characteristics. This paper describes a preparation technique with which the wetting angle between a liquid and fine particles can be derived without modifying the surface texture. This involves coating and adhering a monolayer of the powder on a carrier plate and measuring the composite wetting angle of the particles and the adhesive film. The specification of the adhesive's wetting angle and areal porosity of the carrier medium allows the wetting angle of the given powder subsequently to be evaluated.
POTATO CRISP MOISTURE ESTIMATION USING NEAR INFRARED SPECTROSCOPY

Near infrared spectral analysis is a widely used tool for non-destructive determination of moisture content in food. Moisture in potato crisps is often measured using near infrared analysis, however shape contours and curvatures in samples causes scattering of light, which reduces the accuracy of the measurement. The piecewise multiple scatter correction algorithm is commonly used to reduce the effect of light scattering from the sample. Implementation of the piecewise multiple scatter correction algorithm requires careful selection of scatter correction window size and combinations of spectral wavelength predictors. This paper considers different search heuristics for the purpose of piecewise multiple scatter correction window size selection and optimal spectral wavelength predictor selection. The search heuristics under consideration are a genetic algorithm, hill climbing, feature selection and full spectrum modeling. Calibration models using partial least square regression are formed from the scatter corrected data. The standard error of a cross-validated calibration data set was used to compare the performance of the different techniques. It has been found that a genetic algorithm produced the lowest cross validated standard error from the techniques considered. This suggests that the use of a genetic algorithm resulted in more judicious selection of near infrared model parameters.
The ecology of seed dispersal.

Seed dispersal has long been a topic of interest to naturalists, but it has not been until the last three decades that the ecology of dispersal has received much rigorous scientific attention. Many theoretical and empirical advances have recently been made, although important lacunae in our understanding still need to be filled before dispersal ecology becomes a coherent body of knowledge. A major goal of this chapter is to review the existing literature on seed dispersal, highlighting these essential but missing kinds of information. This review is divided into two sections, the first dealing with the evolution of dispersal mechanisms and the second with the consequences of dispersal at population and community levels. Dispersal can occur in both space and time, but only the former will be treated here, except where some relationship between the two axes is known (Venable and Brown, 1988; Leck et al., 1989; Eriksson and Ehrlen, 1998a; see also Murdoch and Ellis, Chapter 8, this volume).
Synthesis, Characterization, and X-Ray Structure of Bis(O-butyldithiocarbonato)bis(3-ethyl pyridine)nickel(II)

A new series of additional complexes of bis(O-butyldithiocarbonato)nickel(II) with ethylpyridines have been prepared and characterized by physicochemical techniques like elemental analysis, molar conductance measurements, TGA-DTA and UV-visible electronic spectroscopy, and IR-spectral data. The structure of [Ni(S2COC4H9)2(C7H9N)2] has been established by X-ray crystallography. The complex crystallizes in the monoclinic space group P1/n with unit cell parameters , , and A and , , and °. The Ni atom in the title complex is octahedrally coordinated within a trans-N2S4 donor set, with the Ni atom located on a centre of inversion. Crystal structure was solved by direct methods and refined by full matrix least squares procedures to a final -value of 0.0545 for 1984 observed reflections. The butyl chain is disordered over two sets of sites, with occupancy ratio of 0.572 : 0.427.
Highly crystalline ZnO nanoparticles

Highly crystalline, defect free ZnO nanoparticles have been synthesised by the chemical co-precipitation technique. The product sample was characterised by the X-ray diffraction (XRD) and UV-visible absorption spectra. Analysis shows that there is no indication for oxygen vacancies in the as-prepared ZnO nanomaterials. Normally, a green absorption broad band at around 520 nm is observed in the absorption spectrum of ZnO due to oxygen vacancy. This defect is not observed in the present nanomaterial. The shape and size of the prepared nanoparticles were also observed by transmission electron microscope (TEM). The nanoparticles are of semispherical shape having average particle size ∼30 nm. The effect of sonicating time on the morphology of the prepared nanoparticles is also studied. Increasing the sonicating time provides quite spherical well-separated nanoparticles. These remarkable results for producing highly crystalline ZnO nanoparticles with a uniform shapes are quite useful for using them in several applications such as UV light emitting devices and biosensors.
Detection of early events in lipid oxidation by electron spin resonance spectroscopy

Les etapes initiales de l'oxydation lipidique contiennent des reactions en chaine avec des radicaux qui sont des intermediaires a courte vie. L'etendue de ces reactions peut etre suivie par la consommation d'oxygene ou la formation d'hydroperoxydes, produits primaires de l'oxydation lipidique. La technique de resonance electronique spin (ESR) repose sur les proprietes paramagnetiques des electrons non apparies dans les radicaux. La spectroscopie ESR est une methode relativement nouvelle pour l'etude des changements oxydatifs dans les aliments. Cet article de synthese traite de son utilisation dans la detection des evenements dans l'oxydation anterieurs a la formation des hydroperoxydes.
Facile preparation of PdNi/rGO and its electrocatalytic performance towards formic acid oxidation

A highly dispersed and active PdNi alloy supported on reduced graphene oxide (rGO) was successfully prepared for formic acid electro-oxidation under acidic conditions. The material was prepared by a simultaneous reduction method using NaBH4 as the reductant, followed by annealing in H2 at 500 °C. Different characterization methods verified that H2 annealing at an appropriate temperature had a significant influence on both physiochemical composition and electrocatalytic performance of the synthesized catalysts. H2 annealing at 500 °C facilitated formation of a PdNi alloy without agglomeration of the nano-sized metallic catalyst, while without H2 treatment Ni was found predominantly in the form of Ni(OH)2. Cyclic voltammetry and chromoamperometric testing demonstrated that, when compared to the sample without H2 treatment, PdNi/rGO after H2 annealing exhibited better catalytic activity and stability towards formic acid electro-oxidation. The enhanced performance can be explained by the modification of the electronic structure of Pd by Ni after alloy formation and the large specific surface area and excellent electron conductivity of the rGO support.
Controlled synthesis of tellurium nanowires and nanotubes via a facile, efficient, and relatively green solution phase method

Single-crystal trigonal tellurium nanowires and nanotubes were synthesized using a facile, efficient, and relatively green solution phase method with ethylene glycol as solvent and an alternative reducing agent in the presence of NaOH. Large-scale production of slender nanowires and hollow nanotubes with average diameters of 72 and 240 nm, respectively, was achieved by increasing the temperature from 170 °C to 200 °C. Tellurium morphology from nanowires to nanotubes was also controlled by adjusting the NaOH dosage. Scanning electron micrographs show that low temperature or NaOH insufficiency promotes the formation of slender nanowires but counteracts the synthesis of tellurium nanotubes. Detailed reaction equations based on the NaOH dosage were obtained. Preferential growth orientation of [001] was observed in the nanowire and nanotube through high-resolution transmission electron microscopy. Further formation mechanisms dependent on time were systematically studied.
Collisionless gas flows over a flat cryogenic pump plate

This article concerns collisionless gas flows over a flat cryogenic pump plate with a specific sticking probability. It presents exact density, velocity, temperature, and pressure solutions which are useful in determining the plate sticking probability. At any point off the plate, the local velocity distribution function (VDF) consists of several pieces of Maxwellian VDFs, one is characterized by free stream flow properties and the others by plate surface properties. Integrating the VDFs with different moments leads to these exact solutions, which are further validated by simulations with the direct simulation Monte Carlo (DSMC) method. We use these solutions to derive several useful expressions, based on special measured flow field properties at specific locations off the plate, to evaluate the pump sticking probability. Also, the exact solutions complement past studies of aerodynamic coefficients and heat transfer rate for collisionless gas flowing over a flat plate. They explicitly express the physical.
Transient colour centres caused by UV light irradiation in yttrium aluminium garnet crystals

The degrading laser oscillation behaviour in YAG crystals is attributed to the production of colour centres, induced by UV light irradiation. The optical absorption spectrum of UV induced colour centres is investigated using time resolved transient absorption spectroscopy technique. The UV generated spectrum is found to consist of the superposition of three broad absorption bands E1, E2 and E3 peaked near 1.2 × 104, 2.0 × 104, and 2.8 × 104 cm−1, respectively. Various experiments, such as additive coloration, ESR, thermoluminescence, and optical absorption measurement are made. On the basis of experimental results, a model is proposed for the E1, E2 and E3 bands, which are explained by colour centres trapping an electron at an anion vacancy site. Das sich verschlechternde Laserverhalten in YAG-Kristallen wird der Bildung von Farbzentren zugeschrieben, die sich durch UV-Einstrahlung bilden. Das optische Absorptionsspektrum von UV -induzierten Farbzentren wird mit der zeitaufgelosten Absorptionsspektroskopie untersucht. Es wird gefunden. das das UV-erzeugte Spektrum aus der Uberlagerung von drei breiten Absorptionsbanden E1, E2 und E3 bei etwa 1,2 × 104, 2,0 × 104 bzw. 2,8 × 104 cm−1 besteht. Verschiedene Experimente, wie zusatzliche Verfarbung, ESR, Thermolumineszenz und optische Absorptionsmessungen werden durchgefuhrt. Auf der Grundlage der experimentellen Ergebnisse wird ein Modell fur die E1-, E2- und E3- Bande vorgeschlagen, das Farbzentren annimmt, die ein Elektron in einer Anionenleerstelle einfangen.
FORMATION OF SINGLE CHARGED DROPS IN A NON-UNIFORM ELECTRIC FIELD

Formation of single drops in a non-uniform electric field is studied for water drops in the atmosphere and in three kinds of dielectric liquids. Theoretical equations are derived for the volume and the electric charge of the formed drop and corresponding experiments were performed in a range of applied electric potential of 0-7.5 kV. It was clarified that measured drop volumes agree well with theoretical values for systems of liquid-gas and liquid-liquid. The experimental drop charges are not satisfactorily represented by theoretical analysis, but are well evaluated by a semi-empirical equation presented here.
Reliable and non‐destructive Raman analysis to determine the urea concentration in a cream formulation

We present a reliable and nondestructive analytical method for the determination of urea concentration in a pharmaceutical cream formulation using Raman spectroscopy. A pharmaceutical cream is a highly viscous emulsion; therefore, its composition and physical mixing could be inhomogeneous on a microscopic scale. The local environment around the urea could vary, which could influence the molecular vibrations of the urea molecule. As expected, when Raman spectra were collected by focusing the laser onto a tiny area (∼2–3 µm), the position of the urea band at 1003 cm−1 varied as a result of the microscopic inhomogeneity within the sample. Therefore, acquisition of Raman spectra representative of the entire sample rather than a localized portion of it is very important for the analysis of pharmaceutical creams. Based on the preliminary Raman mapping results of a urea cream, a sample area of at least 750 × 750 µm should be covered for reliable quantitative analysis. In this study, we used a wide-area illumination scheme capable of covering a sample area of 28.3 mm2 for Raman spectral collection in order to ensure a reliable representative sample. In addition, to simplify the measurements, Raman spectra of urea creams in plastic bottles were directly collected without further sampling, and partial least squares regression was used for quantitative analysis. The urea concentrations were accurately determined despite the spectral collection being performed through plastic bottles. Copyright © 2010 John Wiley & Sons, Ltd.
Probing electronic lifetimes and phonon anharmonicities in high-quality chemical vapor deposited graphene by magneto-Raman spectroscopy

We present a magneto-Raman study on high-quality single-layer graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride by a dry transfer technique. By analyzing the Raman D, G, and 2D peaks, we find that the structural quality of the samples is comparable with state-of-the-art exfoliated graphene flakes. From B-field dependent Raman measurements, we extract the broadening and associated lifetime of the G peak due to anharmonic effects. Furthermore, we determine the decay width and lifetime of Landau level (LL) transitions from magneto-phonon resonances as a function of laser power. At low laser power, we find a minimal decay width of 140 cm−1 highlighting the high electronic quality of the CVD-grown graphene. At higher laser power, we observe an increase of the LL decay width leading to a saturation, with the corresponding lifetime saturating at a minimal value of 18 fs.
Oxidation of chlorinated ethanes

The photooxidation study was undertaken to gain an understanding of the chemistry of conversion of the chlorinated ethanes to intermediate and final oxidation products. In the study, 10 ppm of each chlorinated ethane and 4 ppm of chlorine were irradiated with ultraviolet light. Three quarters of the lamps used were ''black light'' with a maximum intensity near 3650 A, while the remaining one quarter were ''sun lamps'' with 3100 A maximum intensity. A Fourier Transform spectrometer and a path length of 360 m were used to analyze the reactants and products. Chlorine atoms produced by the photolysis of molecular chlorine initiated the oxidation of each chlorinated ethane. Chlorinated products that formed during the oxidation of the chlorinated ethanes include phosgene, COCl/sub 2/; formyl chloride, HCOCl; hydrogen chloride, HCl; acetyl chloride; CH/sub 3/COCl; chloroacetyl chloride, CH/sub 2/ClCOCl; dichloroacetyl chloride, CHCl/sub 2/COCl; and trichlorocetyl chloride, CCl/sub 3/COCl. Mechanisms are proposed for the formation of these reaction products but are by no means conclusive and warrant further study. Many of the products will be further attacked in the atmosphere to produce HCl, CO/sub 2/, and CO. Hydrogen chloride will probably be washed out of the troposphere by rain but when it is formedmore » at higher altitudes it could persist and enter into the ozone destruction cycle. It is most important that information be obtained on the chemical and physical removal process for phosgene, formyl chloride, and acid chlorides. Of the chlorinated ethanes, methyl chloroform is the least reactive to atmospheric process whereas the 1,1-dichloroethane will likely be the most reactive. « less
Phytochemical And Antimicrobial Characterization Of Rhododendron Anthopogon From High Nepalese Himalaya

Abstract The biological and chemical properties of the medicinally important high altitudinal plant Rhododendron anthopogon D. Don were assayed. Extracts at a concentration of 100 mg-ml-1 from leaves and flowers were collectively obtained by employing hot extraction method with different solvents. The antibacterial and antifungal properties were assayed against different clinical bacteria (two Gram+ and six Gram-) and six phytopathogenic fungi. Klebsiella pneumoniae and Salmonella typhimurium were the most inhibited bacteria, while Fusarium eridiforme, a fungus, was highly inhibited. However, all the tested bacteria were resistant to n-hexane and chloroform extracts. Of all the extracts obtained, the ethyl acetate fraction, followed by the hot methanolic extract, was effective against all the pathogenic strains tested. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) values of ethyl acetate and aqueous extracts on bacteria ranged from 1.562 mg-ml” 1 to 25.0 mg-ml” 1, whereas MIC and MFC (minimum fungicidal concentration) values of n-hexane and ethyl acetate fractions on fungi varied from 1.562 mg-ml-1 to 12.50 mg-ml-1, which are slightly higher than expected. The extracts showed no activity against Exserohilum turticum and Stenophylum sp. There was a highly significant difference in the zone of inhibition between different extract fractions and bacterial or fungal strains. A preliminary qualitative phyto-chemical assay revealed the presence of polyphenols, reducing compounds, quinones, sterol, triterpenes and fatty acids in leaves and flowers of the test plant. The observed antimicrobial effects are believed to be due to the presence of these compounds. The broad spectrum of activity of the extracts would apparently explain the widespread use of this plant for controlling human pathogenic bacteria and phytopathogenic fungi that widely destroy crops in Nepal. This research reveals R. anthopogon to be a highly promising source of potent antimicrobial drugs that could be used to design therapeutic drugs in the pharmaceutical industry.
Controllable ZnO architectures synthesised on zinc substrates by hydrothermal preparation for enhanced photocatalytic activity

Controllable ZnO architectures have been achieved on zinc substrates via a versatile one-pot hydrothermal method without assistance of any surfactants or organic solvent. The morphologies of ZnO architectures have been successfully manipulated by adjusting the concentration of NaOH and temperature of the reaction system. Among the as prepared ZnO architectures, the sheet flower-like ones exhibited highest photocatalytic activity in the degradation of methyl orange (MO) under ultraviolet (UV) illumination for their nanosheets assembled structural feature.
Chemical Structure of Hydrocracked Lignin. Characterization of Hydrocracked Lignin Oligomers

Softwood kraft lignin was hydrocracked at temperatures of 380 °C and 440 °C using a mixture of ferne oxide and sulfur äs catalyst. The products obtained were characterized by gel permeation chromatography, functional group analysis, elemental analysis and C—NMR spectroscopy. The products were found to be of low molecular weight. The aromatic nuclei, were after hydrocracking at 440°Ct mainly of the monohydroxyphenyl and phenyl types. Only small amounts of methoxyl groups and aliphatic hydroxyl groups were found to be present. aand ß-alkyl-aryl ether bonds were completely cleaved during hydrocracking.
Nonvariational calculation of the hyperfine splitting and other properties of the ground state of the muonic helium atom

The properties of the ground state of the muonic helium atom $e\ensuremath{\mu}{}^{3}{\mathrm{He}}^{2+}$ have been calculated nonvariationally, using the correlation function hyperspherical harmonic method utilizing a nonlinear parametrization of the correlation function. The parametrization is similar to the one used in an earlier paper for $e\ensuremath{\mu}{}^{4}{\mathrm{He}}^{2+}$ but the differences in the convergence were found to be important for the choice of optimal parameters. The parametrization is especially suited to accelerate the convergence of singular operators. As a result, the obtained expectation values of the $\ensuremath{\delta}({\mathbf{r}}_{k})$ operators have error margins smaller than the differences in the literature. The lowest-order hyperfine splitting, which depends on the fine structure constant and on the magnetic moment of the ${}^{3}{\mathrm{He}}^{2+}$ nucleus, is compared with values in the literature.
Air Separation by Polymer-based Membrane Technology

Separation of air to produce enriched nitrogen and oxygen has been of great significance to the chemical industry. Membrane-based gas permeation process has gained due importance over conventional methods such as cryogenic distillation, solid adsorption and solvent absorption, because it is economical, compact in size, modular in configuration and has the capacity to offer low specific power consumption. Typical applications of the membrane-produced nitrogen include blanketing, purging, inerting and underbalanced drilling, while the oxygen-enriched air is mainly used for combustion enhancement in furnaces, fuel cells, medical respiration and undersea breathing. Most membranes used in air separation are made of solid polymers. This review seeks to define the current technological factors that govern the field of application of polymeric membranes for the separation of air. Potential membrane materials, physical and chemical modifications of membranes for further research in this area are discussed.