Miracle-dz/UniFAR-FTUs huggingface dataset:
Simultaneous determinations of fluorine, chlorine, and sulfur in rock samples by ion chromatography combined with pyrohydrolysis

We present a simplified method for simultaneous determinations of fluorine (F), chlorine (Cl), and sulfur (S) contents and isotopic abundances in rock samples. After using pyrohydrolysis to extract F, Cl, and S from a sample and transfer it into a sodium hydroxide (NaOH) solution, concentrations of F, Cl, and S as sulfate are measured by ion chromatography. The method is applicable to a variety of rock materials, including peridotite, basalt, gabbro, andesite, rhyolite, sulfide minerals, and possibly to sea salt, with F, Cl, and S contents of several µg g ‐1 to several tens of weight percent in 40 to 250 mg of rock powder. F, Cl, and S contents obtained by 5‐7 repeated analyses of each of nine geological reference materials were in good agreement with previously reported values. In certain reference materials, sulfite peaks were observed, indicating incomplete oxidation to sulfate during S extraction by pyrohydrolysis. However, total S contents in those samples analysed by ICP-AES were also in good agreement with previous reported values. The RSDs of F, Cl, and S contents in reference materials were <6%, except for samples with F content <10 µg g ‐1 (~20%) or S content <~20 µg g ‐1 (<20%). In addition, Cl isotope compositions of seawater (IAPSO Standard Seawater and Pacific Ocean water) from sample solutions in this study were identical within error to reported values, indicating that Cl isotopes do not fractionate during pyrohydrolysis. After small isotopic fractionation corrections, multiple isotope compositions of S ( 32 S, 33 S, 34 S and 36 S) in solutions of sulfide (IAEA-S-1, IAEA-S-2, and IAEA-S-3), IAPSO Standard Seawater, and gabbro (JGb-1), also agree well with their respective reported values. Thus, this method is applicable to obtain accurate Cl and S contents as well as their isotopic compositions from a single aliquot of sample.
Si/Ge core-shell nanoarrays as the anode material for 3D lithium ion batteries

The rapid development of small scale electronic devices, such as M/NEMS devices, smart dust, micro or nano bio-sensors and so on, is leading to the urgent need for micro or nano power sources with the possibility for integration. In this work, 3D Si/Ge composite nanorod (NR) arrays were fabricated on wafer-scale Si substrates as anode materials in micro or nano Li ion batteries (LIBs) by a low cost, simple and Si-compatible process. Significantly improved capacities and cycling performances were accomplished in the optimized 3D Si/Ge composite NR array electrode by successfully addressing the volume expansion and conductivity issues. Further theoretical calculations gain more insights into the origins of the improved electrochemical properties by considering the adsorption and diffusion energies of Li ion in Si and Si/Ge unit cells. This study technically and fundamentally provides a perspective idea for practical applications of wafer-scale Si substrates in LIBs with the aim of supplying integrated power for micro or nano scale electronic devices.
Material Advancements in Fabrication of Mixed‐Matrix Membranes

The mixed-matrix membrane (MMM) is a new membrane material for gas separation and plays a vital role for the advancement of current membrane-based separation technology. Blending between inorganic fillers like carbon molecular sieves, zeolite, metal oxides, silica and silica nanoparticles, carbon nanotubes, zeolitic imidazolate framework, metal organic framework, and glassy and rubbery polymers etc. is possible. Due to mechanical, thermal, and chemical stability, these membranes achieve high permeability and selectivity as compared to pure polymeric materials. Despite of these advantages, the MMM performances are still below industrial expectations because of membrane defects and related processing problems as well as the nonuniform dispersion of fillers in MMMs. Material selection for organic and inorganic phases, preparation techniques, material advancements, and performance of MMMs are discussed. Issues and challenges faced during MMM synthesis as well as problem solutions are highlighted.
Perturbative polydispersity: Phase equilibria of near-monodisperse systems

The conditions of multiphase equilibrium are solved for generic polydisperse systems. The case of multiple polydispersity is treated, where several properties (e.g., size, charge, shape) simultaneously vary from one particle to another. By developing a perturbative expansion in the width of the distribution of constituent species, it is possible to calculate the effects of polydispersity alone, avoiding difficulties associated with the underlying many-body problem. Explicit formulas are derived in detail, for the partitioning of species at coexistence and for the shift of phase boundaries due to polydispersity. Convective fractionation is quantified, whereby one property (e.g., charge) is partitioned between phases due to a driving force on another. To demonstrate the ease of use and versatility of the formulas, they are applied to models of a chemically polydisperse polymer blend, and of fluid–fluid coexistence in polydisperse colloid–polymer mixtures. In each case, the regime of coexistence is shown to be enlarged by polydispersity.
Identification of the Positional Isomers of 2-Fluorobenzoic acid 1-O-Acyl Glucuronide by Directly Coupled HPLC-NMR

Directly coupled HPLC- 1 H NMR was used in the stop-flow mode to separate and rapidly identify an equilibrated mixture of ester glucuronide isomers formed spontaneously by intramolecular rearrangement reactions (internal acyl migration and mutarotation) of 2-fluorobenzoic acid β-1-glucuronide (1-O-(2-fluorobenzoyl)-D-glucopyranuronic acid). The equilibrated mixture of isomers was obtained by incubation of the synthetic 2-fluorobenzoic acid glucuronide in buffer solution (pH 7.4) at 25 °C for 24 h. The β-anomer of the 1-O-acyl glucuronide, and the 2-, 3-, and 4-positional glucuronide isomers (all three as both α- and β-anomers) present in the equilibrium mixture, were all characterized after separation in an isocratic chromatographic system containing phosphate buffer at pH 7.4 and 1% acetonitrile in the mobile phase. The HPLC-NMR investigations also elucidated the mutarotation of the positional glucuronide isomers as well as showing the benefits of the HPLC-NMR technique as a primary analytical tool. This HPLC-NMR method will be of particular value in studies on the acyl migration reactions of nonsteroidal antiinflammatory drug glucuronides which may be related to their toxicological properties.
Particle size as it relates to the minimum film formation temperature of latices

The relationship between the particle sizes and minimum film formation temperature (MFT) of polymer colloids was studied. Early workers had developed theoretical models predicting small particle colloids should coalesce easier and have lower MFTs than those of large colloids. Early published work examining this question reported that MFT was independent of particle size. In 1990, Eckersley and Rudin, using monodisperse acrylic latexes ranging from 148–1234 nm, reported finding that MFT was a function of particle size as predicted. We synthesized a series of monodisperse acrylic copolymer latexes ranging from 63–458 nm and measured MFTs of these latexes and blends of them. We have also found particle size does affect MFT with small particle polymer colloids having lower MFTs than larger ones. Our results differ somewhat in that the MFTs of our latexes are below the glass transition temperatures (Tg) of the polymers while Eckersley et al. report MFTs above Tg.
Total carbon and nitrogen in the soils of the world

The soil is important in sequestering atmospheric CO2 and in emitting trace gases (e.g. CO2, CH4 and N2O) that are radiatively active and enhance the ‘greenhouse’ effect. Land use changes and predicted global warming, through their effects on net primary productivity, the plant community and soil conditions, may have important effects on the size of the organic matter pool in the soil and directly affect the atmospheric concentration of these trace gases.
An inverse Compton scattering (ICS) model of pulsar emission: II. frequency behavior of pulse profiles

The shapes of pulse profiles, especially their variations with respect to observing frequencies, are very important to understand emission mechanisms of pulsars, while no previous attempt has been made in interpreting the complicated phenomenology. In this paper, we present theoretical simulations for the integrated pulse profiles and their frequency evolution within the framework of the inverse Compton scattering (ICS) model proposed by Qiao (1988) and Qiao & Lin (1998). Using the phase positions of the pulse components predicted by the ``beam-frequency figure'' of the ICS model, we present Gaussian fits to the multi-frequency pulse profiles for some pulsars. It is shown that the model can reproduce various types of the frequency evolution behaviors of pulse profiles observed.
A Theoretical Study of the Structure and Spectra of Nitric Acid Hydrates Crystals

Crystals of nitric acid hydrates have been studied theoretically by means of a recently developed ab initio method (SIESTA). Using as input data the X-ray structures of crystals of nitric acid monohydrate (NAM), dihydrate (NAD), and trihydrate (NAT), the atomic geometry within each unit cell has been refined. The calculated geometrical structure of these atmospherically relevant systems allows the study of further physicochemical properties. In this article, their vibrational normal modes have also been evaluated. These have been used to propose the assignment of the observed spectra of the hydrate crystals, with good overall agreement between experiment and calculation. This is the first time that this type of calculation has been carried out for NAD, whose recently observed two phases (I and II) have been studied here.
Kinetics of nutrient release from different organic residues using a laboratory system

Organic residues play a vital role in maintaining soil fertility in arid and semi-arid regions. Knowledge of the nutrient release from organic residues will help in optimizing nutrient efficiency in agricultural crop production systems. This study was conducted to assess the continuous release of phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) from eight different organic residues (sheep manure, beet, waste material, rape, poultry manure, sunflower, potato and garlic) using successive extractions with distilled water. The residues were shaken for 1 h and equilibrated for longer intervals (1, 3.5, 18, 42, 72, 192, 768, 1248, 1608, 1968 and 2328 h) with successive extractions. Cumulative nutrient release curves by different organic residues versus time showed an initial rapid phase followed by a slow phase. The average percentage of nutrients released and the average release rate of nutrients found using a power model was different and were in the order K > P > Ca > Mg and Ca > Mg > P > K, respectively. According to MINTEQ software, the partitioning of total P between HPO4 2− and H2PO4 − is sensitive to the type of organic residue. On average (pooled over all extractions), between 13% (rape) to 40% (poultry) and 27% (poultry manure) to 79% (beet) of total P in aqueous solutions present as HPO4 2− and H2PO4 −, respectively. Among the various organic residues and in the first stage of release, sunflower residue, beet residue, poultry manure and garlic residue had the highest rate constant for Ca, Mg, P and K, respectively, indicating the high potential availability of these nutrients in the early stage of application to soils.
Toxicity and stability of silver nanoparticles to the green alga Pseudokirchneriella subcapitata in boreal freshwater samples and growth media

The toxicity of silver nanoparticles (AgNPs) to green alga Pseudokirchneriella subcapitata was evaluated in standard nutrient medium (ISO 8692), lake water samples from an oligotrophic and an eutrophic lake, and in lake waters supplemented with the standard nutrient medium. Prior to toxicity testing the agglomeration of polyvinylpyrrolidone (PVP) and starch-coated AgNPs was studied in each test medium. Agglomeration was studied by determining the hydrodynamic diameter (HDD). The HDDs for the PVP- and starch-capped AgNP dispersions in deionized water were 40 and 175 nm respectively, indicating the presence of agglomerates. The HDDs of AgNPs remained stable throughout the exposure time in all media used for the toxicity tests. The algae growth inhibition test was performed as a microplate modification of the ISO method using fluorescence detection. The effect of concentration at a 50% inhibition value for PVPcoated AgNPs in standard medium was 115 ± 3 µg/L, and for starchcoated AgNPs 51 ± 32 µg/L. The eutrophic freshwater conditions suppressed the toxicity of the PVP- coated AgNPs, but not the starchcoated NPs. This finding emphasizes the importance of using different AgNPs and natural waters in assessing the environmental risks of silver nanoparticles.
Study of negative oxygen vacancies in Gd2O3-doped HfO2 thin films as high-k gate dielectrics

Negative oxygen vacancies are the origin of intrinsic shallow electron traps in HfO2 gate dielectrics which degrade the electrical properties of the field-effect transistors. In this paper, we study the effect of Gd2O3 doping on the reduction of negative oxygen vacancies in HfO2 thin films. After the deposition of both pure and doped gate dielectric thin films, electrical characterizations such as capacitance–voltage (C–V) and current–voltage (I–V) have been carried out. C–V measurement reveals the presence of negative oxygen vacancies in pure HfO2 dielectrics and a reduction of negative oxygen vacancies after the incorporation of Gd2O3. I–V measurements show a pronounced reduction of leakage current for the doped thin films which attributes to less negative oxygen vacancies. Gd2O3 doping of 15.6 at% has the least negative oxygen vacancies and best dielectric performance. X-ray photoelectron spectroscopy measurements indicate that Gd2O3 has been incorporated into HfO2 and the negative oxygen vacancies are partly eliminated.
Long‐term performance of co‐metabolic degradation of trichloroethylene in a fluidized bed reactor fed with benzene, toluene and xylene

BACKGROUND: Trichloroethylene (TCE) can be degraded under aerobic condition with toluene and other aromatic compounds. Inhibition by primary substrates and toxicity of TCE oxidation influence TCE degradation. RESULTS: Long-term co-metabolic degradation of TCE was evaluated using a laboratory-scale fluidized bed reactor (12 L) with granular activated carbon (1.57 kg) as media and activated sludge as inoculum. The reactor was fed with TCE and a mixture of benzene, toluene and xylene (BTX) and operated with one-pass (hydraulic retention time (HRT) of 5–6 min) for 6 months and then with recirculation (HRT of 20–30 min) for 18 months. BTX/TCE-degrading biofilm was developed within 1 month. TCE was effectively degraded with influent TCE concentrations from 48 to 280 µg L−1. BTX inhibited TCE degradation. Recirculation (or long HRT) increased TCE removal efficiency from 30% with one-pass to 90%. BTX/TCE load ratio influenced TCE removal efficiency and TCE/BTX removal ratio. TCE degradation fitted first-order kinetics. The biomass grown in the reactor also degraded cis-1,2-dichloroethylene (DCE), trans-1,2-DCE and vinyl chloride efficiently except for 1,1-DCE. CONCLUSION: Co-metabolic degradation of TCE by BTX-degrading biomass from activated sludge is sustainable in the long term. BTX/TCE load ratio is a key parameter for TCE removal performance. Copyright © 2008 Society of Chemical Industry
An investigation of elastic moduli of vanadium-chromium alloys

The results of pulse echo measurements on polycrystalline V-Cr samples with approximately 0, 20, 40, 60, 80 and 100 at. % Cr show that the bulk modulus B and the shear modulus G increase nearly linearly with increasing chromium content between 0 and 80 at. % and between 40 and 100 at. % respectively. Due to the Neel point anomaly, the value of B at 100% Cr is about 20% lower than at 80 at. % Cr. In the range below 40 at. % Cr G rises slowly because of the decrease in the molar volume, but is apparently almost independent of the electron concentration. The estimated anisotropy ratio has a fairly marked minimum at about 40 at. % Cr.
Identifying and Analyzing Intermolecular Bonding Interactions in van der Waals Molecules

Atomic interaction lines and (3,−1) critical points were located in the intermoleclar regions of a total of 36 configurations of 11 van der Waals dimers and a trimer, none of which contain a hydrogen bond. The complexes comprised combinations of five moieties: argon atoms and the molecules C2H2, CO2, OCS, and SO2. Atomic interaction lines in the intermolecular region denote the dominant atom−atom interactions underlying the weak interactions. The set of complexes allows us to draw conclusions about the role of the intermolecular charge density in binding. We find that the values of the charge density and its principal axes of curvature at intermolecular critical points in these systems are an order of magnitude less than those found in hydrogen-bonded systems and that the (3,-1) critical points display the hallmarks of “closed-shell” interactions. The strong correlation between the value of ρ at a bond critical point and the binding energy of the complex that has been found previously for hydrogen-bonded.
Multifactor Statistical Analysis of H2O2-Enhanced Photodegradation of Nicotine and Phosphamidon

Direct and indirect photolysis (λ = 254 nm) of aqueous nicotine and phosphamidon were studied. A central composite design was used to explore the effects of initial [H2O2] (0−10 mM), pH (2.8−11.2), and ionic strength (Ic = 0.02−0.71 M) on the rate constants of nicotine and phosphamidon separately dissolved in a surface water surrogate matrix. Five levels of each factor were included in the design. For nicotine, the fastest predicted photochemical oxidation rate constant (k = 0.43 min−1) occurred under the following conditions: pH = 7.5, [H2O2] = 7.5 mM, and Ic = 0.02 M. This rate constant predicts that 90% of the nicotine will react within 5.4 min under these conditions. In general, the photochemical oxidation of nicotine is more rapid at lower ionic strength and near-neutral pH values. For phosphamidon, the fastest predicted oxidation rate constant (k = 0.65 min−1) occurred at a pH of 7.1 and [H2O2] of 5 mM. Under these conditions, 90% of the phosphamidon would react within 3.5 min of treatment. Like nic.
Impedance at Polarized Platinum Electrodes in Various Electrolytes

The results of alternating current bridge measurements of the impedances of bright Pt in contact with 1N aqueous solutions of , , and KI as functions of polarizing voltage and alternating current frequency are presented. The data may be interpreted in a manner similar to that for experiments with acid solutions. Various factors are discussed which may determine the dependence of the impedance on frequency for the electric double layer at rough surfaces.
COMPARISON OF SEVERAL SOIL EXTRACTANTS FOR DETERMINATION OF THALLIUM

Thallium (Tl) and its compounds are toxic to all organisms. Relatively high levels of thallium of pedogeochemical origin have been found in some areas of the Czech Republic. The contents of >2 mg kg−1 of Tl have been found in aqua regia soil extracts of soils originated from melanocratic porphyric hornblende-biotite granite or from hornblende-biotite granodiorite. The contents of Tl in the range of 0.45–1 mg kg−1 have occurred mainly in soils originated from paragneiss. A detailed study of some of these sites has been made. Content of thallium in soils was determined after extraction with aqua regia, 2 M HNO3, DTPA-TEA and 1 M NH4NO3. Plant samples (whole rapeseed kernels) were wet ashed and the total content of Tl was determined. The amount of Tl in soils extracted by the different extracting methods in comparison to aqua regia (100%) was approximately 14% for 2 M HNO3, 0.8% for 1 M NH4NO3 and only about 0.03% for DTPA-TEA. The content of Tl in the rapeseeds was approximately 75% of this element determined in soils after extraction by aqua regia. The relationships among the extractants were found to be relatively close except for 1 M NH4NO3. It was found that the transfer of Tl into rapeseeds depends on the status of this element in the particular soil and that the soil substrate is the main factor influencing this status.
A novel assembling complex of hydrobobic phthalocyanine-cyclodextrin: preparation, characterization, molecular modeling, and in vitro activity

The stable 4 : 1 host–guest complex of phthalocyanine (Pc) and hydroxypropyl-beta-cyclodextrin was designed, computer modeled and prepared. The complex formation can greatly increase water solubility, reactive oxygen generation ability, biocompatibility and, thereby, the in vitro phototoxicity of Pc to cancer cells.
Raman spectroscopic study of the conformational order in hexadecane solutions

The Raman spectrum of hexadecane (n‐C16) has been analyzed in the high frequency C–H stretching region (2800–3100 cm−1). The intensity of the bands was studied as a function of the concentration of n‐C16 when it was diluted in the low molecular weight, quasispherical solvent CDCl3. This solvent does not exhibit any Raman active bands in the region of interest. In order to characterize the influence of the concentration on the local order, parallel studies were conducted on both neat n‐C16 and a very dilute solution of n‐C16 in CDCl3 as functions of temperature. A comparison of these three series of spectra suggests that the neat liquid exhibits about 5% higher trans bond content than does the dilute solution.
Textural and pasting properties of potatoes (Solanum tuberosum L.) as affected by storage temperature

Fresh tubers from five potato (Solanum tuberosum L.) cultivars were stored at different temperatures (4, 8, 12, 16 and 20 °C) and 80–90% relative humidity for 18 weeks after harvest to examine the effect of storage temperature on their textural and pasting properties. Texture profile analysis was performed on raw and cooked potatoes using an Instron universal testing machine to measure textural parameters such as fracturability, hardness, cohesiveness, adhesiveness and springiness. Both raw and cooked potato tubers showed a considerable reduction in all textural parameters upon storage, irrespective of the storage temperature employed. Raw potatoes showed a decrease in fracturability and hardness with increasing storage temperature, whereas their cooked counterparts showed the opposite trend. The extent of change in the textural properties of both raw and cooked potatoes also varied among the different cultivars. Fresh and stored tubers from all cultivars were freeze-dried, ground into flours and analysed for amylose content and pasting properties. The amylose content of flours prepared from potatoes stored at 4 and 8 °C was observed to be considerably lower than that of flours prepared from potatoes stored at 16 and 20 °C. Pasting characteristics such as peak viscosity, setback and final viscosity increased with increasing storage temperature, while the reverse was observed for pasting temperature, when studied using a rapid visco analyser. Breakdown in viscosity of the flour pastes from all cultivars was considerably reduced during storage, irrespective of the storage temperature employed. Copyright © 2006 Society of Chemical Industry