Miracle-dz/UniFAR-FTUs huggingface dataset:
Characteristics of elution profile in radial chromatography under linear conditions

Based on the mass balance equations of solute transfer in the radial chromatographic column, the theoretical expression to describe the column efficiency and shape of elution profile is obtained under linear isotherm case. Moreover, the tendency for the variation of column efficiency and symmetry of peak profile is systematically discussed. The results showed that in radial chromatography the relationship between the column efficiency and volumetric flow rate is similar with that relationship in axial chromatography; relatively high column efficiency still can be obtained under high flow rate in radial chromatography. Accompanying the increase of retention factor of solutes and injection time, the column efficiency decreases monotonously. The effect of column diameter and column length on the column efficiency interfere with each other. It is more advantageous to increase the column efficiency by applying columns with larger column diameter and shorter column length. According to the discussion of the effect of diffusion on the column efficiency, radial chromatography is proved to be suitable for the separation of samples with relatively high diffusion coefficient, which predicts its obvious advantage in the preparative separation of samples such as proteins and DNA.
PHOTOCHEMICAL, CHEMICAL, AND THERMAL STUDIES ON BILIRUBIN IN CdCl3 AND NaOH SOLUTIONS

ABSTRACT This study examined the depletion and growth of bilirubin and biliverdin, respectively, after exposing dilute solutions of the unconjugated specimen of bilirubin to light and heat. Firstly, the solar photolysis of bilirubin in CHCl3 resembled a chemical reaction of bilirubin in CDCl3. Secondly, at temperatures up to about 70°C, appreciable yields of biliverdin were converted from bilirubin in NaOH, before and after irradiation with cool white light produced from a phototherapy facility. This derivation augurs well for purposes of separating suitable quantities of biliverdin for implementation as precursors in biochemical studies. The aspect of the study associated with CDCl3 demonstrated that the systematic decrease in the characteristic bilirubin peak at 453 nm, via a chemical reaction, emulated the photolysis of bilirubin with sunlight in regular chloroform. The respective rate constants of the photochemical and chemical reactions were approximately 0.15 s−1 and 0.17 s−1. The temperature dependence of the conversion of bilirubin in a NaOH solution to biliverdin was examined with high-resolution spectrophotometry. Bilirubin was prepared at low concentrations (typically 10−2 mM) in NaOH and subjected to progressive increases in temperature from 25–67.5°C. No significant changes were observed from the status at 67.5°C on cooling. The results for both CDCl3 and NaOH revealed that a considerable drop in the bilirubin concentrations was encountered. This was accompanied by a corresponding enhancement in the yields of biliverdin in both cases. A mathematical fit to the data provided a means of estimating the level of conversion with temperature.
Removal of cadmium ions from synthetic aqueous solutions with a novel nanosulfonated poly(glycidyl methacrylate) cation exchanger: Kinetic and equilibrium studies

A fundamental investigation of the removal of cadmium ions from aqueous solutions by synthesized sulfonated poly(glycidyl methacrylate) (SPGMA) was conducted under batch conditions. The kinetic and equilibrium results obtained for cadmium sorption with different initial cadmium concentrations onto synthesized SPGMA were analyzed. Kinetic modeling analysis with four different types of kinetic sorption models (pseudo-first-order, pseudo-second-order, simple Elovich, and intraparticle diffusion rate models) was applied to simulate the cadmium-sorption data. The analysis of the kinetic data indicated that the sorption was a second-order process and was pore-diffusion-controlled. An ion-exchange mechanism may have existed in the cadmium-sorption process with the synthesized SPGMA. The cadmium uptake by SPGMA was quantitatively evaluated with equilibrium sorption isotherms. To describe the isotherms mathematically, the experimental data of the removal equilibrium were correlated with the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) isotherm models, and the applicability of these isotherm equations to the sorption systems was compared on the basis of the correlation coefficients. The applicability of the equilibrium isotherm models followed this order: Freundlich > Langmuir > Temkin > D–R. The maximum sorption capacity, determined from the Langmuir isotherm, was 555.55 mg/g at 25°C. Thermodynamic parameters, including changes in the enthalpy, Gibbs free energy, and entropy, were calculated. Positive values for the change in enthalpy and negative values for the change in the Gibbs free energy showed the endothermic and spontaneous nature of sorption, respectively. The relatively small value of the activation energy (32.12 kJ/mol) confirmed that the cadmium-sorption process was diffusion-controlled. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and Formation Mechanism of the Highly Dispersive Silver Powders Used for the Front Paste of the Solar Cell

The preparation of highly dispersive silver particles of average particle size of 1~2μm used for the front paste of the solar cell were carried out by rapid addition of ascorbic acid solution into the aqueous AgNO3 solution at room temperature. The dispersive quasi-spherical silver particles were obtained with the AgNO3 concentration of 0.1M, AgNO3/Ascorbic acid mass ratio of 1:0.8 without controlling the pH value of the system. Elevating the concentrations of the AgNO3 solution resulted in the formation of flowerlike structures. The formation mechanism was investigated, it was concluded that the growth process of the highly dispersive silver particles include three stages, first, the formation of the precursor, followed by the nuclei burst and the diffusive growth process due to formation of H+ ions adsorbed on the negative charged Ag nuclei as well as the steric effect of the ascorbic acid molecule, finally, when the pH value decreased dramatically to approaching the isoelectric point, the adsorbed H+ was released and the resulting primary particles in turn aggregated to form secondary particles.
Intermediate band photovoltaics overview

Intermediate band photovoltaics bases its theoretical superior performance over single gap solar cells on enhancing the photogenerated solar cell current thanks to the two-step absorption of photons with energy lower than the semiconductor gap without degrading the output voltage. Its presumably better utilisation of the solar spectrum has lately become a topic of research, not only because of that of the intermediate band photovoltaic concept itself and the attempts to put it into practise, but also because it has renewed interest in some approaches, such as the up- and down- converters, the impurity photovoltaic effect and the quantum well solar cells, which also aim to utilise sub-bandgap photons. This paper reviews all these concepts.
Automated electron diffraction tomography – a new tool for nano crystal structure analysis

Automated electron Diffraction Tomography (ADT) comprises an upcoming method for “ab intio” structure analysis of nano crystals. ADT allows fine sampling of the reciprocal space by sequential collection of electron diffraction patterns while tilting a nano crystal in fixed tilt steps around an arbitrary axis. Electron diffraction is collected in nano diffraction mode (NED) with a semi‐parallel beam with a diameter down to 50 nm. For crystal tracking micro‐probe STEM imaging is used. Full automation of the acquisition procedure allowed optimisation of the electron dose distribution and therefore analysis of highly beam sensitive samples. Cell parameters, space group and reflection intensities can be determined directly within a reconstructed 3d diffraction volume using a dedicated software package (ADT3D). Intensity data sets extracted from such a volume usually show a high coverage and significantly reduced dynamical effects due to “off‐zone” acquisition. The use of this data for “ab initio” structure solution by direct methods implemented in standard programs for X‐ray crystallography is demonstrated. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of the manganese oxygen-evolving complex in photosystem II of spinach and Synechococcus sp. with multinuclear manganese model compounds by X-ray absorption spectroscopy

The evaluation of Mn X-ray absorption fine structure (EXAFS) studies on the oxygen-evolving complex (OEC) from photosystem II is described for preparations from both spinach and the cyanobacterium Synechococcus sp. poised in the S[sub 1] and S[sub 2] states. In addition to reproducing previous results suggesting the presence of bis([mu]-oxo)-bridged Mn centers in the OEC, a Fourier transform peak due to scatterers at an average distance of > 3 [angstrom] is detected in both types of preparation. In addition, subtle but reproducible changes are found in the relative amplitudes of the Fourier transform peaks due to mainly O ([approximately]1.8 [angstrom]) and Mn ([approximately] 2.7 [angstrom]) neighbors upon cryogenic advance from the S[sub 1] to the S[sub 2] state. Analysis of the peak due to scatterers at [approximately] 3 [angstrom] favors assignment to (per 4 Mn in the OEC) 1-2 heavy atom (Mn, Ca) scatterers at an average distance of 3.3-3.4 [angstrom]. The EXAFS data of several multinuclear Mn model compounds containing such scattering interactions are analyzed and compared with the data for the OEC. Structural models for the OEC are evaluated on the basis of these results. 40 refs., 9 figs., 5 tabs.
Water activities, osmotic and activity coefficients in aqueous chloride solutions atT = 298.15 K by the hygrometric method

Abstract Water activities of aqueous electrolyte solutions of HCl(aq), LiCl(aq), NaCl(aq), KCl(aq), CsCl(aq), NH 4 Cl(aq), MgCl 2 (aq), CaCl 2 (aq), and BaCl 2 (aq) have been determined at T = 298.15 K by the hygrometric method, and at molalities ranging from 0.2 mol · kg − 1 to saturation. From measurements of droplets diameters of reference NaCl(aq) or LiCl(aq), the dependence of relative humidity on solute concentration was determined. The data on the relative humidities allow the deduction of water activities and the osmotic coefficients at different molalities. Osmotic coefficient data have been described by the ion interaction model of Pitzer. The ion interaction parameters were also determined for each of the studied salts. With these parameters, the solute activity coefficients can be predicted. Our present results have been compared with reported thermodynamic data.
MICROWAVE-ASSISTED EXTRACTION OF POLYPHENOLS FROM FRESH TEA SHOOT

Fresh tea shoots (one shoot and two or three young leaves) were extracted using microwave-assisted extraction method (MAE). Several factors such as ethanol concentrations (0-99.5 o (volume percentage)), material: solvent ratio (1:4 to 1:12), extraction time, oven power were studied to optimise conditions at laboratory scale. MAE archived good yield (82.46 %) after 6 minutes microwave radiation, that was higher than that of extraction at room temperature in 24 hours, conventional heating extraction at reflux temperature in 60 minutes or ultrasound-assisted extraction in 60 minutes. Afterward, MAE method was employed to investigate five types (LD97, LDP1, PH1, TB14, HAT) of tea (Camellia sinensis (L.) O. Kuntze) from Bao Loc, Lam Dong. HAT (20.49 % dried weight of total catechins) was found as suitable material for polyphenols extraction.
Zino Oxide Varistors Made from Powders Prepared by Amine Processing

A powder preparation process suitable for varistor production was developed. The mixed acidic solution containing varistor components was added to the diethylamine solution to coprecipitate all components. The resulting mixtures were washed, dried, and calcined to produce active and uniform composition powders. Large nonlinearity coefficient (α∼ 50) were achieved in varistors fabricated from these powders by sintering in the entire range 1100° to 1250°C. Large breakdown fields were also achieved with decreasing sintering temperature. The breakdown voltage per grain boundary of these varistors was approximately 5.2 V.
Radicals and reservoirs in the GMI chemistry and transport model: Comparison to measurements

[1] We have used a three-dimensional chemistry and transport model (CTM), developed under the Global Modeling Initiative (GMI), to carry out two simulations of the composition of the stratosphere under changing halogen loading for 1995 through 2030. The two simulations differ only in that one uses meteorological fields from a general circulation model while the other uses meteorological fields from a data assimilation system. A single year's winds and temperatures are repeated for each 36-year simulation. We compare results from these two simulations with an extensive collection of data from satellite and ground-based measurements for 1993–2000. Comparisons of simulated fields with observations of radical and reservoir species for some of the major ozone-destroying compounds are of similar quality for both simulations. Differences in the upper stratosphere, caused by transport of total reactive nitrogen and methane, impact the balance among the ozone loss processes and the sensitivity of the two simulations to the change in composition.
Experimental and model-based investigation of the links between
snow bidirectional reﬂectance and snow microstructure

Abstract. Snow stands out from materials at the Earth's surface owing to its unique optical properties. Snow optical properties are sensitive to the snow microstructure, triggering potent climate feedbacks. The impacts of snow microstructure on its optical properties such as reflectance are, to date, only partially understood. However, precise modelling of snow reflectance, particularly bidirectional one, are required in many problems, e.g. to process correctly satellite data over snow-covered areas. This study presents a dataset that combines bidirectional reflectance measurements over 500–2500 nm and the X-ray tomography of the snow microstructure for three snow samples of two different morphological types. The dataset is used to evaluate the stereological approach from Malinka (2014) that relates snow optical properties to the chord length distribution in the snow microstructure. The mean chord length and SSA retrieved with this approach from the albedo spectrum and those measured by the X-ray tomography are in excellent agreement. The analysis of the 3D images has shown that the random chords of the ice phase obey the gamma distribution with the shape parameter m taking the value approximately equal or a little greater than 2. For weak and intermediate absorption (high and medium albedo), the simulated bidirectional reflectances reproduce the measured ones accurately but tend to slightly overestimate the anisotropy of the radiation. For such absorptions the use of the exponential law for the ice chord length distribution instead of the one measured with the X-ray tomography does not affect the simulated reflectance. In contrast, under high absorption (albedo of a few percent), snow microstructure and especially facet orientation at the surface, plays a significant role for the reflectance, particularly at oblique viewing and incidence.
Palladium Doped Porous Titania Photocatalysts: Impact of Mesoporous Order and Crystallinity

Herein, we report a facile synthesis method for highly ordered hexagonal P6m mesoporous palladium doped titania nanoarchitectures using the F127 triblock copolymer as a template. The mesoporous Pd/TiO2 nanoarchitectures possess high surface areas of 223 m2g−1 and large pore volumes of 0.42 cm3g−1 at 300 °C that are reduced to 162 m2g−1 and 0.29 cm3g−1, respectively, as a result of calcination at 450 °C with their tunable mesopore diameter ranging from 5.7 to 8.3 nm. Transmission electron microscopy (TEM) measurements evince that the framework of the highly crystalline mesoporous Pd/TiO2 is composed of aligned anatase phase grown along the [101] direction. The Pd nanoparticles are well dispersed and exhibit sizes of about 20 nm and they are separated by 1.95 A, which agrees with the (200) lattice spacing of face-centered cubic Pd. The newly prepared photocatalysts have been compared with Pd photodeposited onto the commercial photocatalyst Sachtleben Hombikat UV-100 by the determination of the rate of HCHO .
Giant Faraday Rotation in Mesogenic Organic Molecules

Faraday rotation, the rotation of the polarization of light due to a magnetic field in the direction of propagation of the light, is used in applications ranging from quantum memory to the detection of biomagnetic fields. For these applications large Faraday rotation is necessary, but absorption of light is detrimental. In search of these properties, we have characterized the Verdet constant of a so far unexplored class of mesogenic organic molecules. We report their spectra and provide an interpretation. A Verdet constant of almost 2.5 × 105 deg T–1 m–1 is found around 520 nm. This Verdet constant is 3 orders of magnitude larger than the largest known for organic molecules in a region without spectral features. We attribute this enormous Faraday rotation to resonant enhancement by a triplet excitation that does not appear in the linear absorption spectrum and to near-resonant enhancement by low-energy singlet excitations. Furthermore we are able to switch the Faraday rotation by changing the liquid cryst.
Fast‐responding thermal‐death‐time tubes for the determination of thermal bacteria inactivation

The knowledge of thermal inactivation kinetics, usually expressed in terms of D‐ and z‐values, is of crucial importance for the design of sanitation and sterilization processes. In this study, we designed a simple, fast‐responding, and mechanically stable aluminum tube for inactivation measurements and compared these experiments with the successive‐sampling method at different temperatures. Up to 65°C, we determined a come‐up time of approximately 15 s for the tubes, which is lower than the corresponding values of other devices, presumably because of lower wall thickness, material properties, and a higher surface to volume ratio. D‐values of Escherichia coli calculated from tube inactivation experiments by first‐order kinetics were 370 s (56°C), 126 s (58°C), 53.2 s (60°C), 33.8 s (62°C), and 3.22 s (65°C), and the corresponding values determined with the successive‐sampling flask method were insignificantly different (417, 138, 48.6, and 29.1 s for 56, 58, 60, and 62°C, respectively). These data as well as those measured for Enterobacter cloacae, Pseudomonas putida, Serratia odorifera, and Yersinia rhodei were in close accordance with literature values.
Physico-chemical properties and heavy metal content of water sources in Ife North Local Government Area of Osun State, Nigeria

The water quality examination in Ife–North Local Government of Osun State Nigeria was conducted by determining the physico–chemical parameters of 40 samples. Surface water, bore holes, wells and pipe borne water samples were collected from major towns in the Local Government Area and analyzed. Results showed temperature range of 26.5 to 33.0°C, pH (6.53 to 8.90), conductivity (63.0 to 1039.0 μS/cm), resistivity (0.00 to 0.02mΩ.cm), salinity (300.00 to 700.00 mg/L), total solids (90.00 to 1175.00 mg/L), total dissolved solids (37.80–622.50mg/l), suspended solids (34.50 to 794.00 mg/L),dissolved oxygen (4.48 to 9.48 mg/L), Biological Oxygen Demand (BOD 5 ) (0.69 to 6.74 mg/L), chloride (3.64 to 184.04mg/L), Nitrate (1.08 to 53.03 mg/L), phosphate (4.99 to 23.07 mg/L) and sulphate (6.02 to 28.95 mg/L). Results of Atomic Absorption spectrophotometric analysis (AAS) of samples for dissolved trace metals; (Cd, Pb, Mn, Zn, Cu, Cr and Fe), showed mean metal concentration to vary widely depending on the source of the water sample as follows: Pb (0.29 ± 0.05 to 6.69 ± 0.53 mg/L), Cd (0.77 ± 0.06 to 2.24 ± 0.08 mg/L), Zn (0.03 ± 2.15 to 0.22 ± 4.64 mg/L), Cu ( 0.18 ± 16.34 to 0.41 ± 5.00 mg/L), Fe (6.00 ± 0.21 to 31.75 ± 0.80mg/L) and Mn (0.14 ± 6.12 to 0.23 ± 99.11 mg/L). The results obtained for the physical parameters agreed with the limits set by both national and international bodies for drinking and domestic water with few exceptions. Key words: Quality, physico-chemical, atomic-absorption-spectrophotometer, domestic, recreational, Ife-North-Local-Government.
A STUDY OF ADSORPTION HYSTERESIS BY MEANS OF LENGTH CHANGES OF A ROD OF POROUS GLASS

From adsorption data and measurements of length changes of a porous glass rod, a qualitative description of the processes involved in the adsorption of water vapor is developed. Particular attention is devoted to the causes of the hysteresis loop. The qualitative theory appears to be useful in understanding the adsorption of water on charcoal, and may therefore be of value in interpreting the phenomenon of limited hysteresis on any porous adsorbent.Three attempts to test the theory quantitatively are presented. These involve the computation of surface areas, of Young's moduli, and of isosteric heats of adsorption. The quantitative treatment also leads to an estimate of the total number of pores and the mean length of the pores, in addition to the pore radius. Such an assessment of a porous structure has apparently not been possible earlier.
Anomalous HNO3/NOx ratio of remote tropospheric air: Conversion of nitric acid to formic acid and NOx?

The N oxidation ratio, [HNO3]/ [NOx], in the free troposphere is measured at ∼ 1 to 9 (averaging ∼5), consistently lower than the values of 15–100 which known theory suggests to be reached rapidly. This discrepancy casts doubt on current models' abilities to predict effects of NO sources on remote [NO], and so also [O3] and [OH]. HNO3-to-NOx recycling processes involving HCHO in solution are appealing explanations for the ratio. Known chemical theory are illustrated using a Lagrangian box model of the mid-troposphere which simulates characteristic episodes from NOx input to HNO3 washout. Ratio and budget constraint equations for NOy, can usefully restrict conceivable explanations of missing chemistry of fast nitrogen cycling; most explanations could be called “fast-cycles” or “re-NOx-ification. ” These equations also show how current global models may suggest spuriously good N oxidation ratios and errors in OH. Aerosol or cloud droplets reactions with HCHO may produce (a) formic acid (which needs an appropriate source) and NOx, or alternatively, (b) hydroxymethyl nitrate (or methyl dinitrate), which might supply a large, variable amount of “missing NOy” not currently measurable except by NOy instruments.
Impact of Aggregate Size and Structure on Biosolids Settleability

Settling is an important solid–liquid separation process in wastewater treatment. While solids concentration is an important factor influencing settling velocity of particles, other solids characteristics including particle size, shape, and structure also play an important role in settling rate. The “compactness” of bacterial aggregates in particular is recognized to exert a great influence on solid phase dynamic behavior since it has a substantial effect on fluid flow through the aggregate, which, in turn, affects the particles buoyancy. With the recognition that biosolids structure can be described by fractal methods, we now have a convenient means of parameterizing aggregate “compactness. ” In this article, we examine the fractal nature of bacterial aggregates (which are the main component of the solids in wastewater treatment processes) using small angle light-scattering methods and assess the impact of aggregate compactness (as described by fractal dimension) on settling velocity of both single aggregates and large aggregate clusters. The results indicate that settling velocity is strongly dependent on both size and aggregate structure, with the larger and less compact flocs settling more quickly as a result of the significant extent of flow through the bacterial assemblages.