Miracle-dz/UniFAR-FTUs huggingface dataset:
Multiscale Model of Carbon Corrosion in a PEFC: Coupling with Electrocatalysis and Impact on Performance Degradation

In this paper we propose a mechanistic model describing the coupling between the polymer electrolyte fuel cell (PEFC) membrane electrodes assembly (MEA) electrocatalysis and the cathode carbon catalyst-support corrosion. The electrocatalysis description includes our previously introduced irreversible thermodynamics nanoscale models of the electrochemical reactions (hydrogen oxidation reaction/oxygen reduction reaction) coupled with the catalyst/ionomer interface double layer phenomena. Physically, the model describes the feedback between the instantaneous performance and the intrinsic cathode carbon oxidation process. It allows exploring the impact of the operating conditions (nominal current, reactant gas pressures, temperature, etc.) and the initial electrodes compositions (carbon and platinum loadings) on the PEFC MEA durability. Some numerical simulations show agreement with experimental knowledge already reported in literature, in particular, when the anode chamber is partially exposed to oxygen (induced by polymer electrolyte membrane crossover or fuel starvation), cathode thickness decrease and cell potential decay are predicted. Furthermore, we found that cathode damage increases as platinum loading increases and as platinum nanoparticles size decreases. Moreover, carbon corrosion favors the platinum coarsening; competition between carbon oxidation reaction and electrocatalytic mechanisms is investigated. Simulations also suggest that an "optimal" external load current inducing a "maximal" durability exists. The sensitivities of the electrochemical impedance spectra to the operating conditions and simulated operation time are also provided.
Analysis of ozone generation from air in silent discharge

A new theoretical model for ozone generation from air is proposed. This model considers the dependency of the ozone dissociation rate by electron impact on the electric field strength, in addition to ozone decomposition processes through the reactions with nitrogen oxides. Assuming a stationary and uniform discharge in time and space, ozone concentrations obtained experimentally under various discharge gap widths and gas pressures are in good agreement with the analytical results. It is concluded that the discharge condition of a narrow gap and accordingly an optimized high gas pressure is one of the most effective means of efficient ozone generation for an air-fed ozone generator.
Development of a validated HPLC-PAD-APCI/MS method for the identification and determination of iridoid glycosides in Lamiophlomis rotata.

An HPLC-photodiode array detector (PAD)-APCI/MS method was developed for the identification of iridoid glycosides in Lamiophlomis rotata (Benth.) Kudo. The regularities of characteristic ions of iridoid glycosides obtained in APCI-MS were analyzed and used to deduce the structure of iridoid glycosides. Compared with the literature on ESI-MS, the deprotonated molecular ions were more outstanding in APCI-MS. Five major active constituents, namely, 8-O-acetylshanzhiside methyl ester, loganin, 8-deoxyshanzhiside, phloyoside II, and shanzhiside methyl ester, were simultaneously determined in ten samples by HPLC. A comprehensive validation of the method included tests of sensitivity, linearity, precision, and accuracy. The linear regressions were acquired with r > 0.999. The precision was evaluated by intra- and inter-day assays, after which relative standard deviation (R.S.D.) values were reported within 2.5%. The recovery studies for the quantified compounds were observed in the range of 95.6-101.2% with R.S. D. values less than 2.1%. The overall procedure may be suitable for the qualitative and quantitative analyses of iridoid glycosides in L. rotata and its preparations.
RHF and DFT study of the molecular properties of the malaria drug proguanil in different environments

The molecular geometries of the common malaria drug Proguanil in gas phase, water and Ethanol have been studied using ab- initio Quantum Chemical calculations at the Restricted Hartree-Fock (RHF) level of theory by employing 6-31+G basis set. Density functional calculation at the Becke3LYP (B3LYP) have been carried out by employing 6-31+G basis set for inclusion of electron correlation. The molecular structure, dipole moment, charge transfer, polarizability and energy were calculated. The shortest bonds were found to be H10-N20, H11-N17, H12-N16, N18-H22 with bond lengths less than 1 A . The dipole moments, thermal energies and polarizabilities were found to be higher in water compared to gas phase and ethanol at both levels of theory. Keywords : Proguanil, Molecular Dynamics, ab initio, DFT Calculations.
Determinants of Woody Plant Species Richness in Abandoned Olive Grove Ecosystems and Maquis of Central Greece

The present study aimed to compare the woody plant species richness and cover (%) of five abandoned olive groves and five maquis ecosystems in central Greece and to describe the relationship between woody plant species richness and a set of environmental variables [soil pH, nitrogen (N), phosphorus (P), potassium (K), and organic matter; air temperature and humidity; altitude; slope; type of ecosystem; and presence of leaf litter]. Although woody plants are abundant in the abandoned olive groves, the number of species and amount of cover (%) are significantly greater in maquis. According to principal component analysis, woody plant species richness was positively correlated with soil organic matter, plant litter, and soil P and K in maquis. Also, woody plant species richness was positively correlated with slope in the abandoned olive groves. Olive grove ecosystems abandoned for at least 12 years have developed species compositions similar to the corresponding features of neighboring maquis, although the number of species and amount of cover (%) are significantly greater in maquis.
Bonding of Methyl Phosphonate to TiO2(110)

We have used scanning tunneling microscopy (STM), noncontact atomic force microscopy (NC-AFM), low energy electron diffraction (LEED), and ab initio calculations to study adsorbates resulting from exposure of rutile TiO2(110)1 × 1 to methyl phosphonic acid (CH3P═O(OH)2). At low exposures, adsorbates appear on the 5-fold coordinated Ti (Ti5c) rows. As the coverage of adsorbates approaches 0.5 ML, STM images show an ordered 2 × 1 overlayer consistent with LEED. We propose that the phosphonic acid is deprotonated with the resulting phosphonate bridging across two adjacent Ti5c atoms in the [001] direction. This bridging conformation would lead to the observed 2 × 1 overlayer and is analogous to that found for a range of carboxylates adsorbed on TiO2(110).
Spectroscopic and Theoretical Study of Cyanidin–Aluminum (III) Complexes

Abstract Complexation of aluminum (III) with cyanidin, a natural anthocyanidin molecule, has been investigated in methanol and buffered solutions of pH 3.0 and 4.0. Electronic absorption spectroscopy was performed to characterize the stoichiometry and stability of the complexes formed. In investigated solvents, aluminum bonded moderately to cyanidin requiring large mole ratios of the components (up to 200) for the access of complexation. Molar ratio plots showed the formation of only one complex with stoichiometry aluminum (III):cyanidin of 1∶1 in both investigated media. Semiempirical calculations, performed in the Austin Model 1 parameterization, enabled the determination of the structural features of free compounds as well as complex structural modifications caused by chelation of Al(III).
Magnetic and viscoelastic study on molten state of low molecular weight isotactic polypropylene

The molten state of a low molecular weight isotactic polypropylene was studied by means of the viscoelastic method as well as the observation of magnetic orientation. The melt viscosity remained at a higher level in the temperature ranging between the melting point (ca. 170 °C) and the temperature up to 70 °C higher than the melting point, depending on the heating rate. The melt viscosity measured at constant temperatures in this temperature range decreased with time. The rate of decrease depended on the temperature. These observations strongly suggested that some ordered structures exist even above the melting point. Magnetic orientation was observed for the samples melted in the magnet (6 T) at temperatures above the melting point. This observation implied the existence of anisotropic structures, supporting the observation made in viscoelastic measurements.
Many-center Coulomb Sturmians and Shibuya–Wulfman integrals†

When momentum space is projected onto the surface of a unit 4-D hypersphere by means of Fock's mapping, Coulomb Sturmian basis functions can be simply represented in terms of hyperspherical harmonics. The properties of these harmonics can be used to evaluate Shibuya–Wulfman integrals and other integrals that arise when the Sturmian basis functions are used in molecular calculations. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Controlled growth of high-quality TiO2 nanowires on sapphire and silica

The vapour–liquid–solid (VLS) growth of TiO2 nanowires (NWs) was performed using a thermally evaporated Ti source and sputter-deposited Au catalysts under an O2 gas flow. High-density single-crystalline TiO2 NWs having the rutile structure were successfully grown on sapphire (single-crystal α-Al2O3) and quartz (amorphous SiO2) substrates. Ti buffer layers, deposited on the substrates to prevent undesirable reactions between the Ti vapour and substrates, were identified to promote the TiO2 NW growth by providing supplementary Ti vapour to the Au catalysts. Crystallinity of TiO2 NWs was investigated by x-ray diffraction (XRD) and their morphological features were characterized by field emission scanning electron microscopy (FESEM). High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) analyses reveal growth of the rutile NWs having twofold twin structures along the growth direction on Ti/sapphire and the defect-free single-crystalline rutile NWs on Ti/quartz substrates. TiO2 NWs grown on Ti/quartz showed a short-wavelength (∼402 nm) and high-intensity photoluminescence (PL) emission compared to those grown on Ti/sapphire substrates. By introducing a Ti buffer layer and using quartz substrates, the crystallinity and PL properties were successfully improved for VLS-grown TiO2 NWs.
Sorption of Polycyclic Aromatic Compounds to Humic Acid As Studied by High-Performance Liquid Chromatography

Aldrich humic acid was chemically immobilized to the silanol surface of a column material to be used for high-performance liquid chromatography (HPLC). The retention factors to the humic acid column material of 45 polycyclic aromatics compounds (PAC) were determined by HPLC. The PAC include PAH, N-, S-, O-PAC and substituted PAC (9-substituted anthracenes, bromopyrenes, and quinoline derivatives). The sorption coefficient of quinoline to humic acid was directly determined at different pH. The good correlation achieved between the HPLC retention factors and literature Koc values, including the presented one of quinoline, was applied to determine Koc of 39 other PAC. The determined Koc values were parametrized with regard to size, ring heteroatoms, and steric and substituent effects and were compared with literature values of water solubility and recently determined octanol−water partition coefficients. It is shown that the sorption of PAC to humic acid is not only affected by hydrophobic interactions but a.
Synthesis of Allyl-cyclopropyl Alcohols and Allyl-1,5-hexadien-3-ols and Investigation of Their Antibacterial and Antifungal Activities.

Two different methods have been used to obtain allyl-cyc1opropyl alcohols and allyl-I ,5-hexadien 3 ols, starting with various allyl substituted chloromethylox iranes. While a llyl substitued 1,5 hexad ien 3 ols are formed in react ions occurring with Mg in THF. the unsaturated cyclic alcohols are also formed. However, the reaction carried out with Na in C H)OH gives only 1,5 dien 3 ols. Antimicrobial activity of the synthesised compound s has been tested against 16 microorganisms. The compounds have also been screened for thei r antibacterial and an ti fun gal acti vi ties aga in st bacteri a. yeasts and moulds.
Molecular dynamics simulations to understand LRKK2 mutations in Parkinson

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of Parkinson's disease (PD). LRRK2 contains a Ras of complex proteins (ROC) domain that may acts as a GTPase to regulate its protein kinase activity. Here, we performed 10 ns molecular dynamics simulations on LRRK2 Apo, complex with GDP and mutations (R1441C, R1441G and R1441H). Our results strongly suggest that the formations of helix in L1 and its pliable plays a major role in the LRRK2 functions.
An approach to theoretical prediction of permeate flux decline in ultrafiltration

Permeate flux decline was predicted by means of Song and Elimelech's [1] model. Theoretical results were compared with those obtained in ultrafiltration experiments where TMP and crossflow velocity were varied. Polyethylene glycol (PEG) of 35000 Da was used in the feed solution in a concentration of 10 g/L. The experiments were performed with monotubular ultrafiltration ceramic (Al2O3-TiO2) membranes of 5 kDa (Tami Industries, France). The model predicted a reduction in the influence of transmembrane pressure (TMP) on permeate flux as TMP increased. This was consistent with the experimental results for the lowest crossflow velocity tested (1 m/s). For higher crossflow velocities the reduction in the influence of TMP on permeate flux as TMP increased was higher than that predicted by the model. Model predictions were better for low crossflow velocities, as expected with a model that considers cake formation as the main fouling mechanism. Rapid initial pore blocking may be the main cause of the discrepancie.
Electrochemical copolymerization of pyrrole and thiophene nanofibrils using template‐synthesis method

Copolymer nanofibrils composed of pyrrole and thiophene were prepared by synthesizing the desired polymer within the pores of microporous anodic aluminum oxide (AAO) template membranes. The copolymer nanofibrils were photographed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for microstructure analyses. The results of the SEM and TEM revealed that the copolymer nanofibrils obtained had uniform and well-aligned arrays and their diameter and length could be controlled by changing the aspect ratios of the AAO membrane. The results of cyclic voltammetry and IR spectrometry indicated that polypyrrole and polythiophene were both involved in the copolymer. The nanofibrils that were obtained were identified as copolymers rather than composites. The influence of the applied polymerization potential on the synthesis of copolymer nanofibrils was investigated. The higher potential favored the incorporation of thiophene units into the copolymer nanofibrils.
Brillouin-Streuung in Strontiumtitanat-Einkristallen im Temperaturbereich 5 °K bis 300 °K

Brillouin-Streuexperimente in SrTiO3 im Bereich der Phasenumwandlung von der kubischen zur tetragonalen Struktur werden mit Hilfe eines Modells für den Phasenübergang gedeutet, das Ergebnisse liefert, die der Theorie von Landau und Khalatnikow entsprechen. Die Phasenänderung wird als Ubergang 2. Ordnung betrachtet, bei dem die beobachteten akustischen Effekte unterhalb der Umwandlungstemperatur auftreten. Als Temperatur des Phasenüberganges wird der Wert 107 + 0,5 °K ermittelt. Die Größe der Stufe in den Brillouin-Verschiebungen konnte aus Literaturdaten, wie Änderungen der Gitterparameter, Drehwinkel der Sauerstoffoktaeder, soft-mode-Frequenzen, vorhergesagt werden. Die Übereinstimmung mit den experimentellen Ergebnissen ist zufriedenstellend. Die Messungen legen eine verhältnismäßig geordnete Domänenstruktur der untersuchten Kristallproben in der Tieftemperaturphase nahe mit einer Domänenorientierung entlang den Achsenrichtungen der kubischen Phase und überwiegend antiparallel ausgerichteten tetragonalen Domänenachsen. Die beim Anwenden einer äußeren Spannung im Brillouin-Spektrum beobachteten Änderungen werden als Umorientierung der Domänenachsen gedeutet
Studies on xanthate–zinc diethyl dithiocarbamate accelerator combination in natural rubber

Abstract Zinc salts of ethyl, isopropyl, and butyl xanthates have been prepared in the laboratory. The synergistic effect of these xanthates with zinc diethyl dithiocarbamate (ZDEC) on the vulcanisation of natural rubber was studied at different temperatures. The amount of the three xanthates and ZDEC in the compounds was optimised by varying the amount of ZDEC from 0 to 1·25 pphr and the xanthates from 0 to 1·5 pphr. The cure characteristics were also studied. The rubber gum compounds with the three xanthate accelerators and ZDEC were cured at various temperatures from 60 to 150°C. The sheets were moulded and properties such as tensile strength, tear strength, crosslink density, elongation at break, compression set, heat buildup, abrasion resistance, and flex resistance were evaluated. The properties showed that the zinc xanthate–ZDEC accelerator system has a positive synergistic effect on the curing and mechanical properties of natural rubber compounds.
Preparation and analysis of a frozen mussel tissue reference material for the determination of trace organic constituents

A new mussel tissue Standard Reference Material (SRM) has been prepared and analyzed for trace organic and inorganic constituents. SRM 1974 (Organics in Mussel Tissue (Mytilus edulis)) is a frozen mussel tissue homogenate that has been certified for the concentrations of nine polycyclic aromatic hydrocarbons (PAHs) from results obtained from gas chromatography-mass spectrometry and reversed-phase liquid chromatography with fluorescence detection. Noncertified concentrations for 19 additional PAHs are also reported. Gas chromatography with electron capture detection and gas chromatography with mass spectrometric detection were used to provide noncertified concentrations for 13 polychlorinated biphenyl congeners and 9 chlorinated pesticides. In addition to the organic contaminants, noncertified concentrations for 36 trace elements were determined primarily by instrumental neutron activation analysis. SRM 1974 is the first frozen tissue SRM for environmental measurements of organic and inorganic constituents.
A Mixed Effect Location-Scale Model with Mixture Distributed Scale Random Effects to Analyze (Near) Identical Entries in Ecological Momentary Assessments

Ecological Momentary Assessment (EMA) studies provide sufficient information to model both the mean (location) and the within-subject variance (scale) using the mixed effect location-scale model (MELS, Hedeker et al., 2008). But in EMA studies, subjects can provide responses with (near) zero variance over time which causes problems for MELS estimation. We extended MELS to address this issue. In conventional two-level MELS, the subject-specific location random effect i affects the mean, and a scale random effect xi affects the variability of the subject’s response at time j, i.e., yij NðXijbþ i, expðWijsþ xiÞÞ: But latent clusters may exist in xi to distinguish subjects with different variance patterns. Instead of assuming xi N 0, rx as in conventional MELS, we specified a Gaussian mixture distribution for xi, e.g., xi pN l1, rx1 þ 1 p ð ÞN l2, rx2 : By making l2 extremely negative, the response variance can be scaled toward zero. For estimation, we incorporated the Maximum-A-Posteriori algorithm into the ExpectationMaximization framework. Given a converged solution, we implemented one extra step of Gaussian Quadrature approximation to the marginal likelihood, yielding the Hessian inverse to provide standard errors (SEs). We first validated our model in three simulation settings: (a) p 1⁄4 0:9, l1 1⁄4 0, l2 1⁄4 10; (b) p 1⁄4 0:6, l1 1⁄4 0, l2 1⁄4 10; (c) p 1⁄4 0:9, l1 1⁄4 0, l2 1⁄4 4: Our proposed model recovered parameter values with negligible biases and approximate 95% coverage rates especially when l1 and l2 were far apart (Settings (a), (b)). More balanced cluster sizes (p 1⁄4 0:6, Setting (b)) and more erratic responses (l2 1⁄4 4, Setting (c)) provided a higher proportion of converged solutions. We applied the extended MELS to the MATCH dataset (Dunton et al., 2015) where six out of 107 wave-1 subjects provided identical negative mood responses (Table 1). Activity level before assessment was hypothesized to be associated with negative mood. Conventional MELS did not converge for the full sample but the extended MELS converged and classified subjects correctly (p 1⁄4 101=107Þ: The b estimates were similar between two models but the different random scale effect distributions affected estimation and statistical inference of s: Activity did not significantly affect the mean (bActivity) and variability (sActivity) of mood.
An Investigation of High Gradient Dielectrophoretic Filtration

Experimental and modelling studies of particle separation from liquids using a dielectric force show that dielectrophoresis may be an appropriate mechanism for multipass filtration systems if the dielectric properties of the fluid and contaminant are favourable. The general trends in filtration efficiency have been identified through an experimental investigation. Higher filtration efficiency is obtained when the viscosity of the liquid is lowered, when the contaminant particle sizes are larger, when the collector particle sizes are smaller and when the concentration of particles in the feed is lower. Efficiency was almost independent of flow rate over the range studied. A model is developed to calculate filter efficiencies; although the general trends in the variation of filter efficiency with process variables can be predicted, absolute values of the calculated efficiencies are too high; ways to improve the model are suggested. A filter design that can be scaled-up has been used in the experimental work, which has identified the main parameters in the process.
Global Kinetic Modeling of Aviation Fuel Fouling in Cooled Regions in a Flowing System

Jet fuel is used to cool military aircraft. Unfortunately, heated jet fuel reacts with dissolved oxygen to form products which foul fuel system components. Two categories of surface deposits which form in the autoxidative regime have been recently identified. The first forms in heated regions as the fuel is oxidized. The second accumulates in cooled regions as certain compounds within the reacted fuel become insoluble at reduced temperatures. This paper seeks to improve understanding of fouling at reduced temperatures and to develop a global chemistry model that can be used in computational fluid dynamics codes. Experiments were conducted in a flowing system using JP-8 fuel with different thermal stability additives. Some thermal stability additives reduced fouling in heated regions but were not as effective in cooled regions. The deposition and oxidation measurements obtained for specific flow conditions were used to calibrate a chemical kinetics model which uses global reactions to simulate deposition. The calibrated model yielded reasonable predictions within the thermal and flow regimes considered.