Miracle-dz/UniFAR-FTUs huggingface dataset:
Potentiostatic Testing of Oxygen Reduction on Polymer Carbon Electrodes

The preparation of polymer carbon electrocatalysts by the controlled pyrolysis of polyfurfuryl alcohol polymer is described. Potentiostatic testing in oxygen-saturated KOH electrolytes is performed, and electrokinetic properties of the electrodes prepared from the electrocatalysts are presented and discussed. It is revealed that a pure polymer carbon electrode pyrolysed in powder form possesses a very high active area, displaying higher catalytic activity than a polymer pyrolysed in bulk. Suitable reduction mechanisms are proposed.
Hydrolytic stabilities of some polyurethane hydrogels

The hydrolytic stability of some polyurethane hydrogels derived from UV-curable urethane prepolymers and hydrophilic monomers was addressed. It was found that polyurethane hydrogels derived from prepolymers with hydrophilic polypropylene glycol soft segments were not stable when the films were cast from nonpolar solvent, whereas they are stable if the films were cast from neat monomer mix. The causes for this instability were analyzed. Spectroscopic and gel permeation chromatographic studies of the water extractables suggested that improper curing of hydrophilic monomers with the urethane prepolymers in nonpolar solvent was mainly responsible for the instability phenomenon.
Development of an Industrial Multi‐Injection Microreactor for Fast and Exothermic Reactions – Part II

A Grignard reaction performed in a microreactor is presented. The reaction is of type A (highly exothermic and very rapid) and has a low yield which is attributed to a hot spot formed in the mixing zone of the reactor. The reaction yield could be significantly increased by applying the multi-injection principle, leading to better thermal control in the microreactor. Nevertheless, the microreactor plays a major role in reducing the magnitude of the hot spot. Knowing this, it was possible to design and construct an industrial microreactor with significant advantages such as modularity, high flow rate operation, and low investment expenditure (pumps and flow controller minimization).
Density Functional Theory Calculation of Adsorption of NaCl on Chlorophyll

We have calculated the vibrational frequencies of chlorophyll-a, chlorophyll-a + 1 NaCl and chlorophyll-a + 2 NaCl from the first principle. We are able to find the vibrational frequencies as well as the structural parameters in all of the three cases. The Mg atoms are found to absorb Na atoms which distort the structure. The vibrational frequencies calculated for the chlorophyll-a are in reasonable agreement with those found from the Raman Spectra.
Synthesis and characterization of polystyrene‐supported glucosamine resin and its adsorption behavior for Au(III)

A novel chelating resin, crosslinking polystyrene-supported glucosamine (PS-GA), was prepared and its structure was confirmed by FTIR, elemental analysis, and X-ray photoelectron spectroscopy. The adsorption properties of PS-GA for Au(III) were investigated. PS-GA resin possessed excellent enriching property to Au(III) ions and adsorption proportion E% could reach to about 90 shortly after 3 h. The adsorption dynamics of Au(III) showed that the adsorption was controlled by liquid film diffusion and the apparent activation energy Ea was 12.91 kJ mol−1. Both Langmuir model and Freundlich model could describe the isothermal process of Au(III), and ΔG, ΔH, ΔS values were calculated. The mechanism of adsorption for Au(III) was confirmed by FTIR, SEM, and XPS. The results showed that redox reaction occurred and both coordination and ion-exchange existed simultaneously in the adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4581–4586, 2006
Removal of Uranium (VI) from Aqueous Solution by Dry Chitosan Powder

This study investigated the likelihood of chitosan powder as a novel type of adsorbent, for U(VI) removal from wastewater. Batch experiments were performed to explore the effect of pH, sorption time, sorption temperature, chitosan dosage on U(VI) adsorption to chitosan powder. The results suggest that the accumulation process was highly pH dependent with pH changing from 2.0 to 7.0. An initial solution pH of 5.0 was most favorable for removal. Over the temperature range from 20 C to 70 C, 30 C was the optimum temperature for the U(VI) adsorption. The U(VI) uptake was rapid within 30 min and equilibrium was reached at 60 min. The U(VI) removal efficiency increased concomitantly with increasing chitosan dosage, while the adsorption capacity decreased. The chitosan had an observed U(VI) adsorption capacity of ca. 175 mg/g dry weight of chitosan. The present results implied that chitosan can be used as a sorbent for an effective removal of U(VI) from wastewater.
3-Dimensional QSAR and molecular docking studies of a series of indole analogues as inhibitors of human non-pancreatic secretory phospholipase A2

Background: Design and development of new drugs is simplified and made more cost-effective because of the advances in the concepts of Quantitative Structure-Activity Relationship (QSAR) studies. A methodology of QSAR studies is one of the approaches to the rational drug design. Methods: 3-Dimensional QSAR studies were performed on a series of indole analogues as inhibitors of human non-pancreatic secretory phospholipaseA 2 (PLA 2 ) by using Scigress explorer software suite. Docking studies of these compounds were also performed to understand the interactions with amino acid residues of PLA 2 protein. Results: The multiple linear regression analysis was used to correlate the physicochemical descriptors with the PLA 2 inhibitory activity of 20 training set of compounds and the best QSAR model was developed. The best model was validated using leave-one-out method and found to be statistically significant, with coefficient of determination (r 2 ) of 0.788. This model was further used to predict the PLA 2 inhibitory activity of 12 test set of compounds. Docking analysis revealed that most of the compounds formed H-bond interactions with amino acid residues of PLA 2 protein (PDB ID: 1DB4). Predicted pIC 50 value of one of the test compounds was 7.454 and it showed H-bond interactions with Asp48, Cys44, His27, Gly29 and Gly31 residues. Conclusion: The present study shall help in rational drug design and synthesis of new selective PLA 2 inhibitors with predetermined affinity and activity and provides valuable information for the understanding of interactions between PLA 2 and the novel indole analogue compounds.
A SIMPLE CORRELATION EQUATION FOR OPTIMIZATION OF RADIATING RECTANGULAR FINS WITH VARIABLE THERMAL CONDUCTIVITY

Radiating extended surfaces are widely used to enhance heat transfer between primary surface and the environment. The performance of such a surface is significantly affected by variable thermal conductivity, particularly in the case of large temperature differences. The aim of the present work is to evaluate the optimum dimensions of radiating rectangular fins with temperature-dependent thermal conductivity for a fixed fin volume. The nonlinear fin equation is solved by the Adomian decomposition method for obtaining the temperature distribution within such fins. The optimum geometry which maximizes the heat transfer rate from the fins of fixed volume is found by using the data from the solution. Derived condition of the optimality is a simple correlation relation between the fin parameter and thermal conductivity parameter describing the variation of thermal conductivity. The resulting correlation equation is a very suitable tool for optimum design of radiating rectangular fins with temperature- dependent thermal conductivity.
China National Biodiversity Information Query System

There is no mechanism for the exchange of biodiversity information in China. It is therefore necessary to establish a system for providing metadata to help people to find data and to understand its content and characteristics. The China National Biodiversity Information Query System (CNBIQS) is just such a metadatabase. Systems analysis, systems design and systems implementation for CNBIQS are discussed in this paper. CNBIQS includes metadata on institutions, data sets, databases, books and maps related to biodiversity. China is rich in information and the system reflects the present status of biodiversity information in the country. It possesses powerful functions for information search, such as query by institute category, query by thematic information category, query by title and query by author. ” 1999 Academic Press
The nitrogen content of type Ib synthetic diamond

Abstract The concentration of single nitrogen atoms in type Ib synthetic diamond has been measured, by electron paramagnetic resonance and by inert-gas fusion, as a function of the strength of the infrared absorption produced by these centres. The two methods yield, in good agreement, values of 22·0 ±. 1·1 at. p.p.m. and 20·6±1·5 at. p.p.m. respectively, for an absorption coefficient of 1cm −1 at 1130 wavenumbers. These values agree tolerably well with an earlier value of 25 at. p.p.m. /cm−1 given by others, so calling into question the generally accepted data pertaining to the strength of the infrared absorption produced by the A centres, or nitrogen pairs, found in type Ia (natural) diamond.
The crystal and molecular structure of sodium uranyl triperoxide

The crystal structure of sodium uranyl triperoxide nonahydrate, Na4[UO2(O2)3],9H2O, has been determined by single-crystal X-ray diffraction, by the heavy-atom method. The main structural feature is the uranyl triperoxide anion consisting of three co-planar peroxide groups equatorially surrounding a linear uranyl group, in approximately D3h symmetry. The mean U–O(uranyl) distance is 1·86, the U–O(peroxide) is 2·28 and the peroxide O–O 1·5 A. The water molecules are co-ordinated in octahedra around the sodium atoms. The crystals are monoclinic, space group P21/c, a= 6·413, b= 17·292, c= 14·186 A, β= 98·52°. The i.r. and Raman spectra of this and some related compounds are reported, with tentative assignments.
Continuous computer controlled production of formate dehydrogenase (FDH) and isolation on a pilot scale

A continuous production process has been developed up to pilot scale (300 l) for FDH production with the methylotrophic yeast Candida boidinii. A high cell mass specific FDH activity (50 U/g) is achieved by process computer controlled supply of pure methanol to operate the reactor at an optimum methanol concentration of 10 g/l. The maximum FDH spacetime yield achievable with this process control involves a residence time of 7 h. The FDH space-time yield (STY) and FDH concentration are a function of the oxygen transfer rate (OTR) of the fermenter (maximum STY = 255 U/(l h) at kLa = 870 l/h). For a reasonable compromise between high FDH space-time yield and high FDH concentration, an optimum residence time is adjustable by regulating the supply of nutrient salt solution in relation to the OTR of the fermenter. On a pilot scale (200 l continuously stirred tank reactor) roughly 4 million U of FDH were produced within 10 days at a residence time of 14.3 h. Isolation of intracellular FDH enzyme was performed using extraction with an aqueous two-phase system (PEG/K2HPO4). A technical product quality of 1.2 U/mg FDH was achieved without any chromatographic purification step.
Hydrophobicity and stability for a family of model proteins

According to the conventional definition, the hydrophobic effect is a result of thermodynamic changes occurring when a nonpolar group dissolves in water and attributable to the fact that water in contact with such a group has special structural and energetic properties. Disagreement now exists as to whether this effect promotes or hinders protein denaturation. Taking the heat capacity change of unfolding as a measure of the hydrophobicity of the protein interior, others have shown that protein stabilities are systematically affected by changes in hydrophobicity. It has been suggested that the observed trends show that hydrophobic hydration is intrinsically a destabilizing factor. Model calculations using known equations for the stability curves and certain simplifying assumptions now show that such regularities provide no evidence for or against this conclusion. All available data can be rationalized if hydrophobic terms are evaluated from models that require a positive hydrophobic contribution to the Gibbs energy of unfolding. The calculations also confirm the recent finding that any set of proteins with denaturation temperatures between about 330 and 380 K that exhibits entropy convergence at about 386 K is thermodynamically required to show enthalpy convergence at approximately the same temperature. © 1993 John Wiley & Sons, Inc.
The ground electronic state of 1,2-dichloroethane I. Ab initio investigation of the geometrical, vibrational and torsional structure

The trans and gauche isomers of 1,2-dichloroethane are characterized using ab initio calculations at the MP4(SDQ) level of theory with the full double zeta polarized D95** basis set. The molecular geometry parameters, the torsion potential and the harmonic frequency of the normal modes of vibrations are calculated. The integrated intensity and the rotational type of the infrared fundamental bands also are determined. New labelling of the normal modes of vibration is introduced for the gauche isomer. The relative abundance and stability of both isomers are discussed. The torsional motion is investigated by means of an effective model taking the geometrical relaxation into account and leading to a theoretical torsional spectrum.
Carbon Dioxide Mitigation by Microalgal Photosynthesis

amount of CO2 is equivalent to about 21% of the entire world’s production. The flue gases’ composition from power plants changes slightly with the specific fuel type and the amount of air used in combustion. Typical flue gas compositions with different fuel sources are approximately 10%. 2 CO2 flue gas concentrations of up to 20% have been measured when coal is burned. 3
Review of stir casting technique and technical challenges for ceramic reinforcement particulate and aluminium matrix composites

Ceramic metal composites are promising advanced materials compared to conventional materials due to special properties such as: low weight, low cost, wear resistance, corrosion resistance, and high strength, etc. Stir casting is one of the lowest costs and simplest ways of making aluminium matrix composites. The main limitations of stir casting are poor distribution with combination of the reinforcement ceramic particles (agglomerations) in the metal matrix, porosities in composites during fabrication, and wettability of ceramic particles with molten metal’s. Enhancement of stir casting parameters for Ceramic-Metals Matrix Composites (CMMCs) is the main objective for many studies. In this paper, the stir casting process will be discussed in detail with parameters affecting the homogeneous distribution of reinforcements, porosities in composites during fabrication, and the mechanical properties of the ceramic metal matrix composites.
Highly Efficient Yellow Organic Light Emitting Diode with a Novel Wet‐ and Dry‐Process Feasible Iridium Complex Emitter

Yellow emission is crucial in RGBY display technology and in fabricating physiologically friendly, low color‐temperature lighting sources. Emitters with both wet‐ and dry‐process feasibility are highly desirable to fabricate, respectively, high‐quality devices via vapor deposition and cost‐effective, large‐area devices via roll‐to‐roll fabrication. Here, high‐efficiency organic light‐emitting diodes with a novel wet‐ and dry‐process feasible yellow‐emitting iridium complex, bis[5‐methyl‐7‐fluoro‐5H‐benzo(c)(1,5) naphthyridin‐6‐one]iridium (picolinate), are demonstrated. By spin coating, the device shows, at 1000 cd m−2, an external quantum efficiency (EQE) of 18.5% with an efficacy of 52.3 lm W−1, the highest among all reported yellow devices via wet‐process, while using vapor deposition, the EQE is 22.6% with a 75.1 lm W−1 efficacy, the highest among all dry‐processed counterparts. The high efficiency may be attributed to the replacement of the hydrogen atom with a fluorine atom on a 2‐substitutional site in the emitter to prevent dense molecular packing‐caused self‐quenching and to reduce radiationless deactivation rates, leading to a high quantum yield (71%).
ANTIOXIDANT ACTIVITY OF ETHANOLIC AND POLYPHENOLIC EXTRACTS OF PORTULACA QUADRIFIDA L.

High intake of fruit and vegetables is believed to be beneficial to human health. Fruit, vegetables and some beverages, are particularly rich in dietary polyphenols. Various studies have suggested that dietary polyphenols may protect against cardiovascular diseases, neurodegenerative diseases and some forms of cancer. In the present study, ethanolic and polyphenolic extract of Portulaca quadrifida Linn. were analysed for their total phenolic content and antioxidant properties. Two main Polyphenols, quercetin and rutin, were identified in polyphenolic extract by HPLC analysis. Antioxidant activity of both extracts was examined by DPPH radical scavenging assay, lipid peroxidation inhibition assay, ferric reducing assay and hydroxyl radical scavenging assay. Both the extracts possessed considerable phenolic content with significant antioxidant activity. Total phenolic contents of EEPQ and PEPQ were found to be 31.3 ± 2.4 and 49.2 ± 2.6 mg of GAE/g respectively. The IC50 values of ethanolic and polyphenolic extracts were found to be 495 ± 2.67 and 320 ± 0. 29µg/ml in DPPH method, 540.34 ± 2.67 and 370.33 ± 2. 91µg/ml in lipid peroxidation inhibition assay, 560 ± 1.89 and 350 ± 1. 28µg/ml in ferric reducing assay and 480 ± 1.23 and 260 ± 0.92 μg/ml in hydroxyl radical scavenging assay, respectively. Antioxidant activity of test extracts was compared with BHT and found significant in all the assays.
The high-pressure phase transition sequence from the rutile-type through to the cotunnite-type structure in

Four phase transitions were observed in under pressure up to 47 GPa using x-ray diffraction in a diamond anvil cell. At close to 4 GPa, rutile-structured underwent a second-order transition to an orthorhombic, -type phase. Above 7 GPa, this -type phase transformed to a cubic phase with a modified fluorite structure. A transition to an orthorhombic phase was observed at 11.4 GPa. The intensities of the diffraction lines in this orthorhombic phase indicate a displacement of the lead ions from the fcc positions occupied in the cubic phase. This orthorhombic phase has similar cell constants (a = 10.027(2) Å, b = 5.246(1) Å, and c = 5.116(1) Å at 26 GPa) to the orthorhombic I phase of and also that of , and could be isostructural. A further transition began above 29 GPa to a cotunnite-type phase, with space group Pnam, and Z = 4, and with a = 5.443(18) Å, b = 6.346(17) Å, and c = 3.368(8) Å at 47 GPa. The coordination number of the lead ion is 6 in the first two phases, 6 + 2 in phase III, most probably 7 in phase IV and 9 in phase V. The volume decreases observed in the three first-order transitions are 6.9, 1.4, and 7.5% at 7, 11.4, and 29 GPa, respectively. The two higher-pressure transitions were reversible, whereas the cubic phase transformed to upon decompression, and this was retained down to ambient pressure. This is the first time a cotunnite-type structure has been adopted by a group IVb dioxide, which has implications for the high-pressure behaviour of the homologous compounds with smaller cations: and .
Swelling kinetics of unsaturated polyester and their montmorillonite filled nanocomposite synthesized from glycolyzed PET

The solvent resistance properties of the unsaturated polyester and their montmorillonite filled nanocomposites are studied in acetic acid through equilibrium swelling method at different temperatures. The kinetics of sorption is studied by using the equation of transport phenomena. The values of ‘n’ in solvent transport equation are found to be below ‘0.5’, showing the non-Fickian or pseudo-Fickian transport in the polymer. The dependence of diffusion coefficient on composition and temperature has been studied for all polymeric samples. The diffusion coefficient of unsaturated polyester samples decreases with an increase in unsaturated acid content. The nanocomposite samples show low diffusion coefficient than corresponding pristine polymers. The diffusion coefficient, sorption coefficient and permeation coefficient increase with an increase in temperature for all the samples. The crosslink density for
Spectrophotometric Determination of Omeprazole Sodium and Ranitidine Hydrochloride Using 2, 4-dinitrofluorobenzene and 4- chloro-7-nitrobenzen-2-oxa-1, 3-diazole Accompanied with a Kinetic Study

Two accurate, simple and sensitive spectrophotometric methods were developed for determination of omeprazole sodium and ranitidine hydrochloride in bulk and pharmaceutical dosage forms. The first method was based on the reaction of these drugs with 2, 4- dinitrofluorobenzene producing yellow colored products measured at λmax 470 nm and 420 nm for omeprazole sodium and ranitidine HCl, respectively. Beer’s law was obeyed in the concentration range from (5-40 µg.ml-1) for omeprazole sodium and (30-180 µg.ml-1) for ranitidine HCl with molar absorpitivity 9.202 x 103 Lmol-1cm-1 and 1.778 x 103 Lmol-1cm-1, respectively. The second method was based on the reaction of omeprazole sodium and ranitidine HCl with 4- Chloro-7-nitrobenzen-2-oxa-1, 3-diazole producing yellow colored adducts measured at λmax 481 nm and 468 nm for omeprazole sodium and ranitidine HCl, respectively. This method was accompanied with a kinetic study for ranitidine HCl. The absorbance-concentration plots were rectilinear over concentration range (2-12 µg.ml-1) and (0.025-0.15 µg.ml-1) for omeprazole sodium and ranitidine HCl with molar absorpitivity 4.062 x 104 Lmol-1cm-1 and 2.802 x 106 Lmol-1cm-1, respectively. These methods hold their accuracy and precision well when applied to the determination of omeprazole sodium and ranitidine HCl in their dosage forms.
FTIR Reflectance vs. EPR Studies of Structural Iron in Kaolinites

The substitution of Fe3+ in the kaolinite structure is studied by EPR spectrometry and by FTIR spectrometry on a large set of kaolins from different origins (sedimentary and primary ores, soil kaolins). The IR bands at 3598 and 875 cm−1, observed in the literature only in the case of disordered kaolins or in Fe-rich environments (synthetic, lateritic), are revealed by high-resolution IR analysis, whatever the origin and the total Fe content of the samples. The EPR bands corresponding to Fe3+ substituted in sites II of the octahedral sheet increase when the IR absorbance near 3600 cm−1 increases. Two IR absorption bands near 4465 cm−1 and 7025 cm−1 are observed for the first time, both in transmission and diffuse reflectance on all samples. These bands are assigned to the combination of the 3598 and 875 cm−1 bands and to the first harmonic of the band at 3598 cm−1, respectively. The area of the band at 4465 cm−1 in diffuse reflectance is quantitatively correlated to the abundance of Fe3+ located in centers II as measured by ESR. This directly confirms the assignment of the two IR bands at 3598 and 875 cm−1 to OH stretching and deformation vibration bands in octahedral FE3+ environment in the kaolinite structure, respectively. Effects due to the size of particles and to the main kaolins impurities on the near infrared spectra, are also discussed.