Miracle-dz/UniFAR-FTUs huggingface dataset:
Continuous Monitoring of Gaseous Formaldehyde Using an Improved Fluorescence Approach

Abstract A continuous monitor for gaseous formaldehyde (HCHO) has been developed which avoids key limitations of previous monitors. The Hantzsch reaction, the cyclization of a β-diketone, an amine, and formaldehyde, is used to produce a fluorescent derivative from HCHO. Use of 254 nm light for excitation provides fluorescence sensitivity nearly four times that obtained previously with 406 nm excitation. This improvement in fluorescence sensitivity leads to a gaseous detection limit of 0.2 ppbv with a glass coil scrubber as the collection device for gaseous HCHO. The Hantzsch reaction provides high selectivity, high reagent stability, and low reagent cost, while the glass coil provides high efficiency, stability of behavior, and simplicity of design. The monitor consequently provides sensitive and specific measurement of gaseous HCHO in a reliable and simple device. The rise and fall times of the instrument response are both 80 seconds, with a lag time of 120 seconds. Repetitive calibrations during extende.
Hybrid model of a plane-parallel hollow-cathode discharge

The development of the hollow-cathode effect in a plane-parallel hollow cathode dc argon glow discharge was investigated experimentally and by means of a two-dimensional self-consistent hybrid model, combining the fluid description of positive ions and slow electrons with a particle simulation of fast electrons. In the experiments the discharge was formed between two flat disc copper electrodes (of 3.14 cm diameter and separated by a L = 2 cm gap) serving as cathodes and a metal tube surrounding these electrodes which served as the anode. The electrical characteristics of the discharge and the spatial intensity distribution of selected spectral lines (Ar I 750.3 nm, 811.5 nm and Ar II 476.5 nm) were recorded at current densities 0.1 mA cm-2 j 0.5 mA cm-2 and for gas pressures 0.2 mbar p 1 mbar. While at pressures of ~1 mbar the cathode regions are developed separately for both cathodes, the light intensity distribution measurements demonstrated the gradual merging of the negative glows with decreasing pressure. At pL 0.8 mbar cm, a common negative glow is formed in the discharge. Complementing the experimental observations, the simulations made it possible to determine various discharge characteristics (e.g. spatial distribution of electric potential, ionization source, and ion density). At low pL values the simulations also indicated the existence of oscillating electrons. The spatial distribution of light intensity calculated for different pressures shows good qualitative agreement with the experimentally observed distributions.
Effect of Cadmium on Uptake and Translocation of Three Microelements in Cotton

Abstract A hydroponic experiment was conducted in a greenhouse to study the effect of cadmium (Cd) on uptake, accumulation, and distribution of three microelements [zinc (Zn), copper (Cu), and iron (Fe)] in cotton during ontogenesis and their difference among genotypes, using 3 genotypes with different Cd tolerances: Zhongmian 16, Zhongmian 16-2 (relatively tolerant-genotypes); and Simian 3 (relatively sensitive-genotype) and treated with 4 Cd concentrations (0, 0.1, 1, and 10 µM). Cadmium concentration in various organs was in the order: root > petiole > xylem > fruiting branch, leaf > phloem in vegetative organs; and in the order: seed coat, seed nut > boll shell > fiber in reproductive organs, respectively. There were no significant differences in Zn, Cu, and Fe concentrations of functional leaves and petioles between 0, 0.1, and 1 µM Cd treatments, while a significant increase with highly significant genotypic difference was observed in 10 µM Cd treatment, when compared with the control. A significant reduction in aboveground vegetative organs and increase in roots were observed for Zn concentration of cotton plants exposed to 1 or 10 µM Cd. The reduction or increase in Zn concentration by Cd differs significantly among the 3 genotypes. One and 10 µM Cd lowered Zn, Cu, and Fe concentrations in aboveground vegetative organs, while increasing concentrations in root, implying that the translocation of these elements from roots to shoots was prevented by Cd treatments. Cadmium treatment did not affect Zn, Cu, and Fe concentration in seed coat, seed, and fiber, while it decreased concentrations in boll shell for all genotypes.
EFFECTS OF SECONDARY AIR INJECTION ON GAS-SOLID FLOW BEHAVIOR IN CIRCULATING FLUIDIZED BEDS

Abstract Effects of secondary air injection on the hydrodynamics such as solid holdup and gas-solid flow behavior were investigated in a circulating fluidized bed. The gas velocity in the riser, the ratio of secondary air velocity to that of primary air, and the solid circulating rate were chosen as operating variables. Fluid cracking catalyst(FCC) with a density of 1840 kg/m3 and a mean diameter of 74 um was employed as the solid phase. The secondary air was fed to the riser radially or tangentially at the wall of the column. Pressure drop fluctuations in the riser were measured and analyzed by adopting the stochastic method to characterize the effects of secondary air injection on the gas-solid flow behavior in the bed. It has been found that the injection of secondary air into the riser can increase the solid holdup in the riser considerably, and that the tangential injection of secondary air is more effective for the increasing the solid holdup than the radial injection. However, the gas-solid flow behavior has been found to become less persistent with the injection of secondary air; the resultant flow behavior is more complex when the air is injected tangentially than radially. The solid holdups in the primary as well as secondary zones of the riser have been well correlated in terms of not only operating variables but also fractal dimension of the pressure fluctuations.
Synthesis of Acrylic-Polyurethane Hybrid Latexes by Miniemulsion Polymerization and Their Pressure-Sensitive Adhesive Applications

The successful incorporation of a NCO-terminated polyurethane (PU) prepolymer in a hybrid miniemulsion is described with the purpose to develop waterborne, high solids, acrylic−PU hybrid nanoparticles to be used in pressure-sensitive adhesive (PSA) applications. To ensure efficient chemical incorporation of the reactive PU into the hybrid latex particles, the NCO moieties were reacted with 2-hydroxyethyl methacrylate (HEMA). The NCO−HEMA coupling reaction was thoroughly studied by conductimetry in order to control the extent of HEMA incorporation into the PU chains. The resulting HEMA-end-capped prepolymers were chain extended in situ with Bisphenol A (BPA) and polymerized with n-butyl acrylate, methyl methacrylate, and acrylic acid in the presence of small amounts of a chain transfer agent to form PU/acrylic particles. The amount of chain transfer agent, the ratio between HEMA and BPA, and the amount of PU were varied step by step to study their influence on the final film properties. The miniemulsions a.
Lateral mobility measurements in organic bulk heterojunctions: comparison of field-effect and space charge mobilities

Measurement of charge transport and recombination parameters in bulk heterojunction (BHJ) materials is of great interest to better understand the science underlying organic solar cells. We discuss the use of space charge limited current measurements under solar illumination to measure the mobility of lateral structures in which charge transport is parallel to the plane of the substrate. We compare these mobilities with mobilities calculated from field-effect measurements of the same structures. Changes in mobility as a function of device length and electric field are consistent with numerical simulations of these lateral structures. Lateral organic photovoltaic structures are potentially very useful in evaluating a number of basic material properties of BHJs including three-dimensional transport.
Study of the Desensitizing Effect of Different [60]Fullerene Crystals on Cyclotetramethylenetetranitramine (HMX)

Three types of [60]fullerene crystals were obtained. The first one was the direct commercial [60]fullerene, and the other two were recrystallized from the first one in carbon bisulfide and in carbon bisulfide/petroleum ether, respectively. Scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), and FT-IR spectrometry were used to study the physical characteristics of the crystals. The thermal stability of the three [60]fullerene crystals was studied by differential thermal analysis (DTA), and the effects of the three [60]fullerenes on the mechanical sensitivity and friction sensitivity of HMX were tested and analyzed. It was found that the three types of [60]fullerenes have different thermal stabilities, and the friction and impact sensitivities of HMX are reduced from 100% to 70% and to 60%, respectively when 1% [60]fullerene 3 was added in HMX.
Optimization of key parameters for chromium (VI) removal from aqueous solutions using activated charcoal.

Commercial activated charcoal was investigated for removal of Cr(VI) from aqueous solutions. The effects of altering the initial Cr(VI) concentration, pH, contact time and amount of activated charcoal were studied. Maximum adsorption of Cr(VI) was achieved between pH 1 - 3 and after a contact time of 120 min. The percentage of Cr(VI) removed decreased from 99.99 - 90.83% when the initial Cr(VI) concentration was increased from 0.05 - 0.5 mg ml-1 at pH 2 and 26 ± 2°C. Various kinetic models such as pseudo first-order, pseudo second-order and Elovich models were used to evaluate the mechanism of Cr(VI) adsorption on activated charcoal. The Cr(VI) removal process was found to be governed by second-order kinetics and the rate constant of the adsorption (k2) was 0.1800 g kg-1 min-1 for an initial Cr(VI) concentration of 0.1 mg ml-1. The adsorption of Cr(VI) was evaluated using Langmuir, Freundlich, and Temkin isotherms and their constants were determined. The maximum adsorption capacity obtained using the Langmuir isotherm model was 45.24 g kg-1 at pH 2. Key words: Key parameters, activated charcoal, adsorption, aqueous solutions, Cr(VI).
Batch Emulsion Polymerization of Styrene Stabilized by a Hydrophilic Macro‐RAFT Agent

Summary: A well-defined homopolymer of 2-(diethylamino)ethyl methacrylate has been synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using (4-cyanopentanoic acid)-4-dithiobenzoate as a chain transfer agent. The corresponding protonated homopolymer with a very reactive dithiobenzoate end group has been used as a water-soluble macromolecular chain transfer agent in the batch emulsion polymerization of styrene without any surfactant. The reaction leads to a stable latex, as a result of the in-situ formation of an amphiphilic block copolymer stabilizer, via transfer reaction to the dithioester functions during the nucleation step. The work does not intend to apply controlled free-radical polymerization in an aqueous dispersed system but takes advantage of the RAFT technique to create a well-defined polyelectrolyte, with a high chain-end reactivity. Schematic of the formation of the stabilized latex by the in situ formation of an amphiphilic block copolymer stabilizer.
Is alkylation the main mechanism of action of the antimalarial drug artemisinin

Artemisinin is a sesquiterpene lactone with an endoperoxide function essential for its antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum. The mechanism of action of this paradigm molecule for endoperoxide-containing antimalarial drugs is still open to debate. Are the artemisinin derivatives only responsible for oxidative stress or are they able to alkylate heme and parasite proteins? The characterization of a covalent artemisinin-heme model adduct supports the role of C-centered radicals generated by the reductive activation of the peroxidic bond of this class of drugs. Artemether (an artemisinin analogue) and BO7 (a synthetic antimalarial trioxane) are also able to alkylate a porphyrin cycle.
Ethylene polymerization by the new chromium catalysts based on amino-pyrrolide ligands

A series of amino-pyrrolide ligands (1-4a) and their derivatives aminothiophene ligand (5a), amino-indole ligand (6a) were prepared. Chromium catalysts, which were generated in situ by mixing the ligands with CrCl3(thf)(3) in toluene, were tested for ethylene polymerization. The preliminary screening results revealed that the tridentate amino-pyrrolide ligands containing soft pendant donor, 3a, 4a/CrCl3(thf)(3) systems displayed high catalytic activities towards ethylene polymerization in the presence of modified methyaluminoxane. The electronic and steric factors attached to the ligand backbone significantly affected both the catalyst activity and the polymer molecular weight. Complex 4b was obtained by the reaction of CrCl3(thf)(3) with one equivalent of the lithium salts of 4a, which was the most efficient ligand among the tested ones. The effect of polymerization parameters such as cocatalyst concentration, ethylene pressure, reaction temperature, and time on polymerization behavior were investigated in detail. The resulting polymer obtained by 4b display wax-like and possess linear structure, low molecular weight, and unimodal distribution.
Proper correction for the basis set superposition error in SCF calculations of intermolecular interactions

The effects of basis set extension to the space of the partner monomer in supermolecular SCF and perturbation calculations have been analysed for the model He2 and HeLi+ systems. In contrast to the suggestions of many authors it is demonstrated that the correction for the basis set superposition error should be calculated with the full basis set of the dimer without removing the occupied orbitals of the partner monomer. In fact, the enlargement of the monomer basis set by the partner occupied orbitals effectively improves the first-order exchange interaction energy. For the first-order electrostatic interaction energy any enlargement of a poor or medium size basis set of the monomer by the partner orbitals worsens its value.
Binary and ternary blends of polyethylene, polypropylene, and polyamide 6,6: The effect of compatibilization on the morphology and rheology

The effects of two compatibilizing agents, polystyrene–poly(ethylene butylene)–polystyrene copolymer (SEBS) and SEBS-grafted maleic anhydride (SEBS-g-MAH), on the morphology of binary and ternary blends of polyethylene, polypropylene, and polyamide 6,6 were investigated with scanning electron microscopy and melt rheology measurements. The addition of the compatibilizers led to finer dispersions of the particles of the minor component and a decrease in their size; this induced a significant change in the blend morphology. The rheological measurements confirmed the increased interaction between the blend components, especially with SEBS-g-MAH as the compatibilizer. New covalent bonds could be expected to form through an amine–anhydride reaction. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1976–1985, 2004
EFFECT OF SOLVENT EXTRACTION SYSTEM ON THE ANTIOXIDANT ACTIVITIES OF ALGAE

Objective : The present study aimed to determine the antioxidant activities of five algae including Oedogonium globossum, Pithophora oedogonia, Rhizoclonium hieroglyphicum , Scytonema ocellatum and Spirogyra communis and the effect of different solvent (benzene, chloroform, acetone and methanol) used for the extraction of active components from algae. Methods: The five algae were extracted with four different solvents e. g benzene, chloroform, acetone and methanol. The Folin-Ciocalteu procedure was used to estimate the amount of total phenolic content in different extracts of algae. Total flavonoid content was estimated by aluminium chloride colorimetric method. The DPPH radical scavenging assay was used to find out the antioxidant activities of algae under investigation. Results: The total phenolic content varied from 9.80±0.29 to 44.44±2.26 mg/g, 7.26±0.08 to 21.30±0.17 mg/g, 9.82±0.12 to 50.14±0.99 mg/g and 11.51±0.17 to 54.02±0.58 mg/g dry material in the benzene, chloroform, acetone and methanol extracts of the algae respectively. The flavonoid content was found to be the highest in the acetone extract of Scytonema ocellatum (593.81±2.69 mg/g) and flavonol content was found to be the highest in the chloroform extract of Scytonema ocellatum (448.22 ± 4.36 mg/g) whereas least amount of flavonoid present in the benzene extract of Oedogonium globossum 8.91±0.37 and least amount of flavonol was present in the chloroform extract of Spirogyra communis (13.54±1.07 mg/g). The highest DPPH radical scavenging was observed in the methanol extract of Scytonema ocellatum with IC 50 = 0.24±0.003 mg dry material. The reducing power of the extracts of the algae was also evaluated as mg AAE (ascorbic acid equivalent)/g dry material. Chloroform extract of Rhizoclonium hieroglyphicum showed the highest reducing power 185.56±2.00 mg AAE/g dry materials. Conclusion: Thus it could be suggested that these algae can be utilized as natural antioxidant.
The influence of preparation methods and surface properties of activated carbons on Cr(III) adsorption from aqueous solutions

Activated carbons were prepared from eucalyptus wood, by using three different “physical” activating methods: air and CO2 partial gasification of wood char (2 hr, 400°C and 800°C, respectively), and direct CO2 partial gasification of wood sawdust. The three activated carbons were then oxidized with HNO3 for increasing the surface concentration of oxygenated functions, and Cr(III) aqueous solution adsorption isotherms were determined for each oxidized carbon. Characterization of the carbons were done through elemental analysis, N2 adsorption, and Fourier transform infrared spectroscopy spectra. Results show that oxidized activated carbons prepared from air gasification have the higher Cr(III) adsorption capacity. Conclusions about chemical functions formed onto the carbon surface and the relationship with Cr(III) adsorption are exposed.
Layer-dependent resonant Raman scattering of a few layer MoS2

We report resonant Raman scattering of MoS2 layers comprising of single, bi, four and seven layers, showing a strong dependence on the layer thickness. Indirect band gap MoS2 in bulk becomes a direct band gap semiconductor in the monolayer form. New Raman modes are seen in the spectra of single- and few-layer MoS2 samples which are absent in the bulk. The Raman mode at similar to 230 cm(-1) appears for two, four and seven layers. This mode has been attributed to the longitudinal acoustic phonon branch at the M point (LA(M)) of the Brillouin zone. The mode at similar to 179 cm(-1) shows asymmetric character for a few-layer sample. The asymmetry is explained by the dispersion of the LA(M) branch along the G-M direction. The most intense spectral region near 455 cm(-1) shows a layer-dependent variation of peak positions and relative intensities. The high energy region between 510 and 645 cm(-1) is marked by the appearance of prominent new Raman bands, varying in intensity with layer numbers. Resonant Raman spectroscopy thus serves as a promising non invasive technique to accurately estimate the thickness of MoS2 layers down to a few atoms thick. Copyright (C) 2012 John Wiley & Sons, Ltd.
Density functional studies on the electron affinities of DNA and RNA bases

Influence of basis sets on electron affinities (EAs) of DNA and RNA bases has been investigated using density functional method (B3LYP functional) with different basis sets (6-31G, TZVP and 6-311+ + G**). Effect of some PBE functionals namely, PBEOP, PBELYP and PBEVWN, on EA values of the nucleobases was studied using basis set which predicted the most reliable values with B3LYP functional. Observation of the trends in the values of EA and dipole moment of the molecules enable us to identify the features of a basis set that shows the presence of dipole-bound state of some of the nucleobases. The vertical electron affinities with B3LYP and PBEOP functionals are close to the experimental values. The adiabatic electron affinities of uracil and thymine were found to be positive for basis set with diffuse functions using B3LYP functional. Adenine does not have a stable covalently bound anion at all levels of basis sets and functionals. The sign of adiabatic electron affinity value of cytosine is inconsistent with that of experimental value but in agreement with previous theoretical results. For guanine the adiabatic electron affinity value with 6-311+ + G** basis set was found to be very high as comparison with other two basis sets confirming the formation of mixed covalent-dipole character.
Production of polystyrene/poly(ethylene glycol dimethacrylate) composite particles encapsulating hinokitiol

Polystyrene (PS)/poly(ethylene glycol dimethacrylate) composite polymer particles containing hinokitiol (HT) were produced by suspension polymerization for ethylene glycol dimethacrylate droplets by the dissolution of HT and PS in poly(vinyl alcohol) aqueous solution. The composite particle had a hollow structure in which HT was included. The evaporation rate of HT from the composite particles became slower than that of pure HT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 706–710, 2003
2-(Biphenyl-2-yl)-5-(1-methyl­hydrazino)-1,3,4-thia­diazole: a thia­diazole–hydrazine derivative with anticonvulsant properties

In the title compound, C15H14N4S, the outer phenyl ring makes an angle of 101.4 (2)° with the plane through the inner benzene ring, and the planes of the thia­diazole ring and the attached benzene ring inter­sect at an angle of 146.7 (2)°. In addition to weak N—H⋯N hydrogen bonds, creating a two-dimensional network parallel to the bc plane of the crystal structure, there is also one non-standard hydrogen-bond inter­action of the type C—H⋯N. Stereochemical comparison with the closely related compound 1-[5-(biphenyl-2-yl)-1,3,4-thia­diazol-2-yl]methanaminium chloride shows that the two compounds utilize the same mechanism for anticonvulsant activity.
Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules

Two extended basis sets (termed 5–31G and 6–31G) consisting of atomic orbitals expressed as fixed linear combinations of Gaussian functions are presented for the first row atoms carbon to fluorine. These basis functions are similar to the 4–31G set [J. Chem. Phys. 54, 724 (1971)] in that each valence shell is split into inner and outer parts described by three and one Gaussian function, respectively. Inner shells are represented by a single basis function taken as a sum of five (5–31G) or six (6–31G) Gaussians. Studies with a number of polyatomic molecules indicate a substantial lowering of calculated total energies over the 4–31G set. Calculated relative energies and equilibrium geometries do not appear to be altered significantly.