Miracle-dz/UniFAR-FTUs huggingface dataset:
Characterization of Homogeneity of Bubble Flows in Bubble Columns Using RPT and Fibre Optics

Homogeneous flows of air-water in two bubble columns, 0.130 m and 0.292 m in diameter, were investigated using RPT (radioactive particle tracking) and fibre optics. The homogeneity of bubble flows at U g < 0.04 m/s was revealed not only in the hydrodynamics of the gas/liquid phase but also in the transport phenomena (turbulence intensity ). RPT Lagrangian data derived that turbulence was about 0.15 m/s for the radial direction and 0.26~0.35 m/s for axial direction in the 0.292 m column, 0.05~0.16 m/s for the radial direction and 0.25~0.35 m/s for the axial direction in the 0.13 column. Average bubble diameter was 4~5.3 mm and was almost constant for the radial locations. The result was twice the sizes of the predicted bubble sizes in the CFD modeling. The slip velocity was 0.3 m/s at U g=0.015~0.033m/s as it was assumed in many reactor designs, and only a small variation was found at the radial locations. In flow patterns, stable circulation cells were revealed using velocity vector plots if a single nozzle sparger was used in the 0.13m column, which confirmed Joshis assumptions (Joshi and Sharma, 1979) and Lins assumption (Lin et al., 1996) based on 2-D columns. Using a perforated sparger was helpful to form a stable mean velocity field. Mean bubble diameters and bubble size distribution varied only slightly with radial/axial locations, which was consistent with the homogeneity of radial/axial turbulence. Bubble-size evolution from their formation to equilibrium mean diameter was discussed. Mean bubble size correlation was approached. The homogeneity of investigated flows was also substantiated by the criteria of stability for bubble flows.
Chemical and isotopic heterogeneity in protosolar matter

It is argued that the inner Solar System is chemically fractionated with regard to the bulk Solar System. It is enriched in refractory and depleted in volatile elements. Carbonaceous chondrites reflect the major fractionation trends of the present inner Solar System material. Other groups of meteorites are indicative of processes in more local environments. Although the element pattern of material in the inner Solar System bears some resemblance to that in grains of the interstellar medium (ISM), Solar System materials have, with few exceptions, no memory of their ISM origin. After decoupling of the Solar System from ISM, isotopic and elemental remixing occurred followed by metal, forsterite and volatile element fractionations.
Formation of Heterocyclic Amines in a Meat Juice Model System

Bovine meat juice was used as a model system to examine the kinetics of the formation of heterocyclic amines. The formation was examined at temperatures between 100 and 225°C for 0.5-180 min. Heated samples were subjected to solid-phase extraction and HPLC analysis. IQx, MelQx, 7,8-DIMelQx, 4,8-DiMelQx, PhlP, harman and norharman were identified. The formation of the IQx derivatives and PhlP followed a first-order model C t =B(1 -e k 1 (t 1 -t 0 ) ), and the temperature dependence followed the Eyring equation k=k b T/he ΔS/R e -ΔH/RT . The parameters In the first-order model and the Eyring equation could be estimated from our data. The degradation of heterocyclic amines at high temperatures was analyzed and the products were found to be less mutagenic.
A Comparison of Porous and Non-Porous Gas-Liquid Membrane Contactors for Gas Separation

Measurements have been made on the separation of CO 2 from gas phase by aqueous absorbents (water and diethanolamine solution) using non-porous and microporous hollow fibre membrane modules. The use of an absorbent liquid in the permeate side of the permeator enhances CO 2 separation and reduces the requirements for a high pressure ratio across the membrane. A mathematical model based on the effective permeability of the gaseous mixtures has been used to assess the performance of both hollow fibre membranes, and a correlation for the shell side mass transfer has been developed. Overall mass transfer in the microporous and non-porous membranes is dominated by the liquid film coefficient and a combination of liquid film and membrane resistances, respectively.
Influence of polymer structure on adsorption behavior at solid–liquid interface by Monte Carlo simulation

Monte Carlo simulations for the adsorption of polymers including random copolymer, homopolymer, diblock copolymer and two kinds of triblock copolymers, respectively, in nonselective solvent at solid–liquid interface have been performed on a simple lattice model. The effect of polymer structure on adsorption properties was examined. In simulations, all polymeric molecules are modeled as self-avoiding linear chains composed of two segments A and B while A is attractive to the surface and B is non-attractive. It was found that for all polymers, the size distribution of various configurations is determined by the linked sequence of segments and the interaction energy between segment and surface. The results of simulation show that the adsorbed amount always increases with increasing bulk concentration but the adsorption layer thickness is mostly dependent on the adsorption energy at a fixed fraction of segments A. On the other hand, diblock copolymer has always the highest surface coverage and adsorbed amount, while random copolymers and homopolymers give generally the smallest surface coverage and adsorbed amount. It is shown that the sequence of polymer chains, i.e. molecular structure, is the most important factor in affecting adsorption properties at the same composition and interaction between segment and surface. The results also show that the adsorption behavior of random copolymers is remarkably different from that of block copolymers, but acting like homopolymer.
THERMODYNAMIC AND ANALYTICAL STUDIES ON THE CHARGE-TRANSFER COMPLEX FORMED BETWEEN CHLORANILIC ACID AND AMINO DERIVATIVE OF METRONIDAZOLE.

The nitro group of metronidazole was converted to the amine derivative before complexation with chloranilic acid; the charge-transfer complex was analyzed spectrophotometrically. There was a bathochromic shift in the absorption of chloranilic acid from 420 to 440 nm on the formation of the complex. The stoichiometry of complexation was found to be 1:1. The equilibrium constant for the interaction at different temperatures was determined according to Benesi-Hildebrand model. The equilibrium constant and molar absorptivities varied only slightly with temperature. The thermodynamic parameters like free energy change (ΔG), enthalpy change (ΔH ) and entropy change (ΔS ) showed that the interaction was exothermic. Quantitative analysis of four brand of metronidazole showed mean percentage recoveries of 98.78 ± SD 0.045 for charge-transfer technique and 95.93 ± SD 0.31 for the Standard method. The limits of detection (LOD) and quantitation (LOQ) were 25 ng/ml and 70 ng/ml respectively. Comparison of these techniques shows that there is no significant difference (p > 0.05) between the two methods. Charge-transfer technique is suitable for the quantitative analysis of metronidazole because it is simple, sensitive and accurate. KEY WORDS: metronidazole derivative, charge-transfer complex, chloranilic acid. Global Jnl Pure & Applied Sciences Vol.10(1) 2004: 125-131
Decontamination of Alkaline Radioactive Waste by Ion Exchange

An ion-exchange process was developed to remove cesium-137, strontium-90, and plutonium from alkaline salt solutions. About 20 million gal of alkaline salt cake and supernatant solution from processing nuclear fuels and materials for defense programs are presently stored at the Savannah River Plant. Ion exchange may be used to decontaminate this radioactive waste during a proposed waste solidification program. In development tests 100-L quantities of liquid waste were decontaminated. Decontamination factors were 4 x 10/sup 5/ for /sup 137/Cs, 5 x 10/sup 3/ for /sup 90/Sr, and 300 for Pu. The separated radionuclides were concentrated by a factor of 1500 and immobilized by adsorption onto zeolite. Residual /sup 137/Cs, /sup 90/Sr, and Pu activity in the decontaminated product was about 6 nCi/g. /sup 106/Ru, the most hazardous radionuclide remaining after /sup 137/Cs removal, will decay to 6 nCi/g about 10 years after the waste is processed.
Synchrotron-generated time-resolved fluorescence anisotropy studies of the segmental relaxation of poly(acrylic acid) and poly(methacrylic acid) in dilute methanolic solutions

The fluorescence anisotropy data for poly(acrylic acid) and poly(methacrylic acid) in dilute methanolic solutions, as analyzed by a variety of data retrieval procedures, indicate that a single exponential function is sufficient in description of the relaxational behavior of these systems. The segmental motions of PAA and PMAA in methanol are characterized by rotational correlation times of ca. 1.3 and 4.2 ns, respectively
Trapping and surface permeation of deuterium in He‐implanted Fe

Iron was ion implanted with He and deuterium (D) and then heated at a constant rate of 2 K/min. The evolving depth distribution of the D was monitored using the nuclear reaction 2D(3He,p)4He, and resulting data were analyzed by applying the diffusion equation with appropriate trapping terms. Two defect traps for D were identified, the respective binding enthalpies being 0.53±0.07 and 0.71±0.07 eV when referenced to a solution site. The weaker of these traps is believed to be a monovacancy, while the stronger may be a vacancy cluster. A third type of trap, with strength 0.78±0.08 eV, was found to be associated with He. It is proposed that the responsible entities are ∼1 nm He bubbles which were observed by transmission electron microscopy, and that the D is bound to the walls of these bubbles by a mechanism similar to chemisorption. The analysis also yielded an estimate of the D recombination coefficient at the electropolished and air‐exposed Fe surface, ∼5×10−19 cm4/s at a temperature of 500 K.
Diffusion-Limited Current Density of Oxygen Reduction on Copper

There are many important processes in corrosion for which the diffusion-limited current density of oxygen reduction, i L , plays a dominant role in terms of kinetic control. The conventionally accepted value of i L (for the four-electron reduction mechanism) which can be found in many corrosion textbooks is in the range of 50-100 μA cm -2 , but the origins of this range of values are a bit mysterious. Previous research in our group aimed at ascertaining i L (under stagnant conditions) on a planar Cu electrode and a Cu microelectrode array in a naturally aerated 0.1 M Na 2 SO 4 electrolyte found that i L was in the range of 20-30 μA cm -2 . In situ scanning tunneling microscopy was used to characterize the Cu surface at relevant potentials. Rotating disk electrode studies were used to measure i L in a naturally aerated 0.1 M Na 2 SO 4 electrolyte as a function of pH for both Pt and Cu electrodes. By comparing results for Pt and Cu we conclude that oxygen reduction occurs on a Cu surface via the four-electron mechanism. The oxygen diffusion-limited current density was found to be independent of pH (in the range 1.5-14). Finally, we conclude that our previous determination of i L in a stagnant electrolyte reflects an accurate range of values of the oxygen diffusion-limited current density.
A review of chemical diffusion: Criticism and limits of simplified methods for diffusion coefficient calculation

A review of the physics and modelling of mass diffusion involving different gaseous chemical species is firstly proposed. Both accurate and simplified models for mass diffusion involve the calculation of individual species diffusion coefficients. Since these are computationally expensive, in CFD they are commonly estimated by assuming constant Lewis or Schmidt numbers for each chemical species. The constant Lewis number assumption is particularly used. As a matter of fact, these assumptions have never been theoretically justified nor verified in practical flames. The only published information are the first observations by Smooke and Giovangigli about the Lewis number against temperature distributions in methane–air premixed and counterflow diffusion one-dimensional flames. The aim of this work is to verify these assumptions. Functional dependences of molecular properties appearing in these numbers are made explicit to show that while Sc i depends only on composition, Le i depends also on temperature and therefore it certainly cannot be assumed constant in a flame. Then, accurately calculating molecular properties, distributions of these characteristic numbers against temperature are obtained a posteriori from numerical simulations of different flames, premixed and non-premixed, and burning different fuels. For non-premixed flames, individual species Lewis number distributions are broad for most of the species considered in this article, whilst they are tight for premixed flames. Some attention is focused on the particular shape of Lewis distributions in non-premixed flames: they are characterized by four or five (when extinction is experienced) branches associated to precise regions in the flame (basically, lean, rich and stoichiometric combusting zones). Instead, the Schmidt distributions are always tighter, also when extinctions take place: for many species they can be approximatively assumed constant. Finally, a simplified procedure to estimate individual species diffusion coefficients is suggested, assuming the median of non-premixed flame Schmidt distributions has a constant value for each chemical species.
Ferroelectricity and strain effects in orthorhombic YMnO3 thin films

We report on the dielectric properties of epitaxial [0 0 1]- and [1 0 0]-textured thin films of antiferromagnetic orthorhombic YMnO3 and their variation under compressive epitaxial strain. It is found that weakly strained YMnO3 films are ferroelectric with a polarization along the c-axis switchable by 90° by an external magnetic field. With reducing film thickness and increasing epitaxial strain, the ferroelectric order is progressively suppressed. Analysis of structural, dielectric and magnetic data indicates that suppression of ferroelectricity with reducing thickness is accompanied by an enlarged ratio a/b of the in-plane cell parameters of the orthorhombic structure and the appearance of a net magnetization. All results can be well-described by considering the multiferroic phase diagram of orthorhombic manganites.
Synthesis and characterization of poly(ethylene succinate) and its copolyesters containing minor amounts of butylene succinate

Poly(ethylene succinate) (PES) and its copolyesters that contain 7, 10, or 48 mol % butylene succinate (BS) were synthesized through a direct polycondensation reaction with titanium tetraisopropoxide as the catalyst. Measurements of intrinsic viscosity (1.08–1.27 dL/g) proved the success of the preparation of polyesters with high molecular weights. The compositions and the sequence distributions of the copolyesters were determined from 1H and 13C NMR spectra. The distributions of ethylene succinate and BS units were found to be random. Their thermal properties were elucidated using a differential scanning calorimeter (DSC) and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters. All of the copolymers exhibit a single glass transition temperature. Wide-angle X-ray diffractograms (WAXD) were obtained from polyesters that were crystallized isothermally. The DSC thermograms and WAXD patterns indicate that the incorporation of BS units into PES significantly inhibits the crystallization behavior of PES. The heat of fusion of ideal PES crystals is 163 J/g, as determined by the depression of the melting point of PES crystals in acetophenone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Lactonization of ω-Hydroxycarboxylic Acids Using (4,5-Dichloro-6-oxo-6H-pyridazin-1-yl)phosphoric Acid Diethyl Ester

E-mail address: yjyoon@gnu.ac. kr Received July 30, 2008(4,5-Dichloro-6-oxo-6H-pyridazin-1-yl)phosphoric acid diethyl ester (3) is an efficient coupling agent forlactonization of aliphatic and aromatic ω-hydroxycarboxylic acids. Lactonization of ω-hydroxycarboxylicacids with 3 in the presence of equimolar amounts of a base gave the corresponding monoolides, diolides,triolides and/or tetraolides.Key Words : Lactonization, ω-Hydroxycarboxylic acid, (6-Oxo-6H-pyridazin-1-yl)phosphoric acid diethylester, LactoneIntroductionLactonization is an important process in the synthesis ofthe natural product.
Comparison of the Structure and Porous Texture of Alumina Gels Synthesized by Different Methods

Alumina gels are synthesized by different methods. Those methods include the drying of xerogels by simple evaporation either in water or in an another solvent, the supercritical drying either in alcohol at 260 °C or in CO2, after hydrolysis in an organic solvent in order to make aerogels, and the supercritical drying either in methanol or in CO2, after hydrolysis in excess water followed by exchange of the initial water for another organic solvent. These three different synthesis procedures result in different pore textures, from micropores to mesopores, which had different resistance to elimination by sintering during heat treatment up to 1200 °C. Xerogels with micropores in a planar texture configuration keep the smallest residual specific area at 1200 °C, while aerogels hydrolyzed in an organic solvent with a random network of mesopores keep a higher residual specific surface area at the same temperature.
The Diamagnetic Anisotropy of Large Aromatic Systems: Parts I and II

Part I. A short discussion is given of the magnetic properties of large aromatic hydrocarbons and of the applicability of various wave-mechanical methods of calculating the diamagnetic susceptibility. The ultimate particles of most cokes and carbon blacks are not sufficiently large to be regarded as crystalline and must be treated as large molecules: calculations on certain simple types of molecule are to be carried out with a view to elucidating the effect of particle size and shape on the magnetic properties of such carbons. For systems of these dimensions the molecular orbital method should be valid and, in fact, appears to constitute the only feasible approach to the problem. Part II. The method of molecular orbitals is applied in a discussion of the diamagnetic anisotropy of the p-polyphenyls, which may be regarded as the simplest type of aromatic chain molecule. An almost perfectly linear relationship is predicted between diamagnetic anisotropy and chain length: in this case the molecular orbital method should be valid for chains of up to at least 2,000 rings. The results are discussed and the desirability of further accurate experimental work on these molecules is pointed out: this would make possible a stringent test of the whole theory.
Optical properties of pure water

The optical properties of pure water are basic input data for many geophysical investigations such as remote sensing of surface water and underwater radiative transfer calculations. Knowledge of the spectral properties of components in surface water is required for accurate interpretation of measured reflection and attenuation spectra in terms of their concentrations. Also the sources and sizes of errors in the basic data must be known. Absorption measurements were done with a submersible absorption meter in the temperature range 2.5 till 40.5 degree(s)C. The scattering of pure water is recalculated using the Einstein-Smoluchowski equation. The input for this equation is evaluated and the temperature dependency is included. New values for the absorption coefficient are given based on these results and analysis of data from the literature. Absorption in the wavelength range 300 - 550 nm is lower than presently used values. In the wavelength range about 700 nm the spectrum has a different shape. A formulation of the effect of temperature on the absorption spectrum is given.
Ready‐to‐eat snack products: the role of extrusion technology in developing consumer acceptable and nutritious snacks

Summary Consumer appeal for ready-to-eat (RTE) products is forecast to grow rapidly over the next 5 years as consumers demand convenient snacks with exciting sensory and textural properties. Extrusion technology has been used extensively in the production of cereal RTE snacks due to its ease of operation and ability to produce a variety of textures and shapes which appeal to consumers. Many of the existing RTE products are relatively high in sugar and salt, thus being regarded as energy dense but nutritionally poor foods. However, there exists a potential to manipulate the nutritional status of extruded RTEs by altering the digestion potentials of starch and protein, and by the incorporation of bioactive components such as dietary fibre. The review article explores some of the recent research in this field and illustrates opportunities by which the global food industry could react to consumers' requirements for healthful RTE snack products in the coming years.
Chlorophyll meter predicts nitrogen status of tall fescue

Abstract The nitrogen (N) status of a crop can be used to predict yield and supplemental N fertilizer requirements, and rapid techniques for evaluating the N status of crops are needed. A study was conducted to determine the feasibility of using a hand held chlorophyll meter (SPAD 502, Minolta Co. Ltd., Japan) to monitor N status of tall fescue (Festuca arundinacea Schreb.). Four diverse tall fescue genotypes were grown at three locations in Alabama and fertilized at four N‐rates from 0 to 336 kg ha‐1. A similar experiment was conducted in the greenhouse using soil from the same field sites. Chlorophyll meter readings (SPAD) were taken, and extractable chlorophyll content, tissue N concentration and dry matter yield were determined at harvest. SPAD, extractable chlorophyll content, tissue N concentration, and dry matter yield increased quadratically (0.67 < R2 < 0.99) with increasing N fertilization in both experiments. All genotypes responded similarly to applied N, with some differences in magnitude. Re.
COMPARISON OF THE EFFECT OF EXPOSURE TO FILTER CIGARETTE AND NONFILTER CIGARETTE SMOKE IN RAT BRONCHOALVEOLAR LAVAGE FLUID AND BLOOD : THE ANTIOXIDANT BALANCE AND PROTEASE-ANTIPROTEASE BALANCE IN VIVO

It is unclear whether the filter has any effect on cigarette smoke toxicity. We investigated whether there are differences between filtered and nonfiltered cigarette smoke in biochemical markers in body fluids. Wistar rats were exposed to filtered (F) or nonfiltered (N) cigarette smoke for 3 mo, 6 cigarettes for 30 min/day, 5 days/wk. Nicotine and tar quantities were 25% and 30% less, respectively, for filter cigarettes than with nonfilter cigarettes. The control animals (C) inhaled clean room air. Cells and biochemical markers in blood and bronchoalveolar lavage fluid (BALF) were analyzed. The smoke-exposed groups showed decreases in weight gain, total protein, and vitamin E in blood, and increases of albumin/ globulin and vitamin C in serum. These findings were not observed for filter cigarettes except for vitamin C. The N group revealed a tendency for decrease in 1-globulin content. Greater increases in white blood cell counts and serum vitamin C were observed in the F group than in the N group. Serum .