Miracle-dz/UniFAR-FTUs huggingface dataset:
Evaluating virial coefficients for multicomponent mixtures: hard sphere mixtures and flexible chains

A new algorithm to compute the virial coefficients of multicomponent mixtures is proposed. The number of graphs that must be evaluated increases dramatically in a multicomponent mixture so that it becomes difficult to enumerate and compute all possible graphs. However, once all of them are known and evaluated, the virial coefficient of the mixture can be evaluated for any composition. If one is interested in the virial coefficient of a mixture of a certain composition, then a simpler approach can be followed. Starting from the graphs of a pure fluid, we assign a random chemical identity to each of the molecules of the graph. The probability of assigning a given chemical identity is taken from the composition of the mixture. In this way composition is treated as a random variable within the Monte Carlo procedure which determines the virial coefficient. The algorithm is checked by comparison with the virial coefficients of binary hard spheres mixtures which are well known. Good agreement is found. The procedure is then extended to multicomponent mixtures of hard spheres. Finally the procedure is applied to the determination of the virial coefficients of a flexible molecule. For flexible molecules the possible configurations of the molecules are treated as different components of the mixture. In this way we present what appears to be the first determination of the third and fourth virial coefficients of polymers in the continuum.
Optical limiting and nonlinear optical absorption properties of C60–polystyrene star polymer films: C60 concentration dependence

The optical limiting behavior and the nonlinear optical properties of pure C60–(polystyrenex)y (C60–(PSx)y) star polymer, and C60–(PSx)y incorporated in a polystyrene matrix, are reported. Two, four and six polystyrene arms of controllable length were grafted directly on the C60 cage, preventing aggregation of the fullerene molecule, and consequently permitting achievement of high C60 concentrations. The optical limiting behavior of these films was measured below the damage threshold, and the nonlinear absorption coefficient β was determined by the Z-scan technique, using nanosecond 532 nm and sub-picosecond 497 nm laser radiation. In some of the samples, the high concentration of C60 gives rise to intermolecular interactions, which diminish the average molecular nonlinear optical properties of the film. However, the observed dependence of the nonlinear optical properties as a function of laser pulse duration and C60 concentration may be relevant to applications of these compounds in solid state devices.
Gas diffusion in random binary media

The binary representation of porous media can provide a direct means for the characterization of their internal structure and is becoming progressively fashionable as a result of the rapid development of novel, powerful image analysis techniques. In the present work we provide accurate predictions of the Knudsen and intermediate diffusivities based on molecular trajectory computations in three-dimensional pixelized porous media. The main advantage of this approach is that it avoids resorting to the commonly used concepts of pore, grain, or fiber models, which introduce inevitably a significant degree of approximation to the actual structure. A second advantage is that this method is valid even far from the continuum limit where rarefied transport prevails. An analytical expression for the Knudsen diffusivity in random binary media is suggested that combines simplicity and accuracy over the entire porosity range. In the intermediate diffusion regime, it is found that the serial combination of the overall b.
Calculation of a generalised smectic–hexatic phase diagram in liquid crystals

This study gives a generalised smectic–hexatic phase diagram calculated by the Landau mean field theory. Our calculated phase line equations are fitted to the experimental phase lines, which represent first-order transition for the liquid crystals studied here. The temperature- and concentration-dependent phase lines calculated in this study describe the observed T–X phase diagram for the smectic–hexatic transitions. This indicates that the method of calculating the phase line equations from the mean field theory is general and it can be applied to other phase transitions in liquid crystals.
Distributed magnetic field sensor based on magnetostriction using Rayleigh backscattering spectra shift in optical frequency-domain reflectometry

We present a distributed optical-fiber magnetic-field sensor based on magnetostriction using the Rayleigh backscattering spectra (RBS) shift in optical frequency-domain reflectometry (OFDR). The magnetostrictive Fe–Co–V alloy thin films are attached to a 51-m single-mode fiber (SMF). We detect the strain coupled to the SMF caused by the magnetic field using the RBS shift. We measure the range of the magnetic field to be from 0 to 143.3 mT. The minimum measurable magnetic intensity variation is 12.9 mT when the spatial resolution is 4 cm, and it can be improved to 5.3 mT by deteriorating the spatial resolution to 14 cm.
Measuring the CO2 production from maize‐straw‐amended soil columns— a comparison of four methods

A soil-column experiment with maize-straw application at different depths was carried out to investigate the accuracy of CO2-measurement systems in a greenhouse experiment with sandy and loamy soils. The classical approach of CO2 absorption in NaOH solution was compared with three other methods using dynamic chambers. These methods were gas chromatography (GC), a portable infrared analyzer (IR), and a portable photo-acoustic system (PAS). The cumulative CO2 production over the 57-day incubation period was significantly affected by the method and soil-specifically by the treatments. The NaOH and GC method always formed a pair of lowest cumulative CO2 production in all treatments with maize-straw addition. In the treatments with bottom application of the maize straw, IR and PAS methods gave values at identical levels in both soils. In the treatments with top application of the maize straw, the IR method gave significantly highest values in the sandy soil and the PAS method in the loamy soil. The correlation coefficients between the cumulative CO2 production of the three dynamic-chamber methods (GC, IR, and PAS) and the static NaOH method were all significant, with r values between 0.90 and 0.93. The C balance can be used for testing the plausibility of CO2-production data. Roughly 102% (NaOH and GC) and 114% (IR and PAS) were recovered, including the CO2-production data in the C balance of the sandy soil. The respective data were 97% (NaOH and GC) and 104% (IR and PAS) for the loamy soil.
SIMULATING PROCESSES OF SOIL PHOSPHORUS IN GEOLOGICALLY YOUNG ACIDIC SOILS OF FINLAND

To properly simulate phosphorus (P) loading from agricultural land to waters, changes in soil P status and processes affecting soil P have to be described adequately. For practical reasons, a model has to rely on data that are commonly available. In this study, the P submodel of the ICECREAM model, based on the CREAMS, GLEAMS, and EPIC models, was adapted to simulate young acidic soils, which prevail in Finland. These soils have a high P sorption capacity, plenty of inorganic P in a non-reactive apatitic form, and the organic matter content (Or) in the plow layer is commonly about 5%. The model was modified mainly on the basis of 12 long-term fertilization experiments and tested on three other soils. The P pools considered were labile P (Pil), active inorganic P (Pia), stable inorganic P (Pis), fresh organic P (Pof), and more stable organic P (Poh). The major model modifications made were: (1) initialization of Pil from the Finnish soil test results (ammonium acetate extractable P, PAAc); (2) initialization of Pia and Pis from Pil, assuming equilibrium; (3) revision of the P availability factor (Fl), which regulates the flow between Pil and Pia; and (4) calculation of the initial values of Poh from soil organic carbon content. These modifications aimed to improve simulation of Pil on the basis of data obtained from soil testing. Proper simulation of changes in Pil, reflected by the soil test P (PAAc), is critical since it regulates the level of dissolved P in runoff water. After the modifications, the model was able to predict changes in PAAc at annual P application rates of 0 and 30 kg ha-1 in cereal cropping, but could not fully cope with a large surplus of P resulting from an annual rate of 60 kg P ha-1.
High-pressure direct synthesis of aluminium nitride

We report the results of direct synthesis of aluminium nitride (AlN) under high nitrogen pressure up to 1 GPa and temperatures up to 2000 K. At pressure from 10 to 650 MPa we observe the combustion synthesis of AlN. As the result of the combustion process one can obtain the AlN sintered powder or AlN/Al metal matrix composites. For N2 pressure higher than 650 MPa the crystal growth of AlN from the solution of atomic nitrogen in aluminium is possible. Both needle-like and bulk AlN single crystals, up to 1 cm and 1 mm, respectively, have been obtained.
Nascent product excitations in unimolecular reactions: The separate statistical ensembles method

The unimolecular reaction of a vibrationally excited molecule having low rotational excitation often leads to nascent products in which the vibrational degrees of freedom appear ‘‘hotter’’ than the rotation, translation (R,T) degrees of freedom. We show that this can derive from parent vibrations being ‘‘hot’’ while parent rotations remain ‘‘cold,’’ since the parentage of product vibration is parent vibration, while product R,T excitations are obtained from parent vibration as well as rotation. Calculations are performed for reactions having loose transition states and no reverse barriers, in which an ensemble of 3N–6 degrees of freedom are used to equilibrate parent vibrations, thereby providing a statistical distribution of product vibrational excitations. For each set of product vibrational states, all R,T excitations are then apportioned statistically using the phase space theory of unimolecular reactions (PST). The results indicate that for those energies above reaction threshold (E‡) which exceed th.
Effect of Regen-Ox oxidant as a modifier on crude oil extraction by supercritical carbon dioxide

The effect of the addition of the commercial oxidant RegenOx consisting of two parts (part A, the oxidizer powder, and part B, the liquid activator) to supercritical carbon dioxide on crude oil recovery was investigated in a broad range of pressures from 20 to 60 MPa at 60 °C. The addition of part B did not improve recovery. With the addition of part A, however, the pressure effect contributed to higher recovery in the range of 45–60 MPa, producing an increment of 15% compared to 8% in the range of 20–40 MPa. The effect of the mixture of part (A + B) of RegenOx did not show any effect on oil recovery at lower pressures in the range of 20–40 MPa, but there was a 14% average increment in recovery at pressures of 45 MPa and above, closely mimicking the trend produced by the effects of part A alone. A chromatographic analysis of the extracts obtained by supercritical carbon dioxide from the addition of a mixture of both parts of RegenOx has shown that the concentration of C18–C30 single carbon groups increase.
Static SIMS inter-laboratory study

An inter-laboratory study involving 18 respondees, with 21 static SIMS instruments, has been conducted with a wide variety of spectrometer types. These include quadrupole, magnetic sector and three time-of-flight mass analyser designs, representing an essential cross-section of the main laboratories using static SIMS. This study involved the static SIMS analysis of three reference samples provided by the NPL: poly(tetrafluoroethene), poly(ethene terephthalate) and a thin layer of Irganox 1010 on silver. Respondees recorded data for both positive and negative secondary ions in the static mode and, if time permitted, as a function of the ion fluence. The results of this study show that static SIMS instruments can have excellent repeatabilities of better than 1%. A relative instrument spectral response (RISR) is calculated for each instrument with an average reproducibility of 14%, for the different reference materials and for both ion polarities. The RISR facilitates the transferability and equivalence of data from laboratory to laboratory. This means that spectra have a reproducibility, after correction using the RISR, of ×/÷1.14 compared with a value four times worse with no correction. Problems that lead to variability are the sample handling and sample contamination, the energy band pass of the spectrometer and the mass transmission function of the analyser. However, dominating all of these, at the present time, seems to be the local procedures for set-up and use of each instrument. It is believed that, if these can be improved, static SIMS can be a reliable measurement method. Copyright © 2000 John Wiley & Sons, Ltd.
Confinement of excitons in spherical quantum dots

The ground-state energy of excitons confined in microspherical crystallites with a finite-height potential wall is studied variationally as a function of the particle radius in the so-called strong-confinement regime. Exciton energies for dot radii in the range 5-40 A are calculated and compared with experimental and theoretical data for CdS, CdSe, PbS and CdTe crystallites. This comparison shows that the effective-mass approximation and spherical confinement geometries are appropriate for all of the particle sizes. Our results also show that the quantum dot cannot be modelled using an infinite-barrier-height potential in the strong-confinement regime.
Détermination, par diffraction des rayons X, de la teneur en phase amorphe de certains matériaux minéraux

Habituellement, le principe utilise pour determiner la teneur en verre des materiaux consiste a soustraire de 100% la somme des teneurs des phases cristallisees, ces dernieres etant determinees en DRX par analyse quantitative. Il existe un interet a tenter de developper des methodes, basees sur la diffraction des rayons X, permettant d'evaluer directement la teneur en verre de ces materiaux ou encore de simplifier les methodes indirectes existantes. Notre demarche vise a developper des nouvelles methodes de mesures directes et indirectes de la teneur en phase amorphe des materiaux mineraux synthetiques (composition connue) et de production industrielle. Quatre methodes sont proposees. Leur application sur un total de dix materiaux mineraux a permis d'obtenir des resultats coherents, avec une precision de l'ordre de quelques pourcents, ce qui peut s'averer suffisant pour la plupart des applications en genie civil.
Transparent Thermal Insulation With Infrared-Absorbing Gases

We investigate the radiative heat transfer between blackbody-like surfaces confining an infrared-absorbing gas layer. Spectrophotometric measurements on selected gases lead us to optimized compositions with sulfur hexafluoride, propyne, and different freons. Theoretically, the gas is able to diminish the radiative heat flux across a 1 cm thick slab by a factor - 0.7 in comparison with the case of a non-absorbing medium. Infrared-absorbing gases seem to offer interesting possibilities for improved transparent thermal insulation of windows.
The Essential Oils of the Aerial Parts of Two Hypericum (H. pseudolaeve Robson and H. thymbrifolium Boiss. & Noë) (Guttiferae) Species from Turkey

Abstract In this study, essential oil composition of two Hypericum L. (Hypericum pseudolaeve Robson and H. thymbrifolium Boiss. & Noë) species grown in Turkey were determined by using GC and GC-MS system. The essential oils obtained by hydrodistillation from the aerial parts of plants. Forty-five compounds were identified in the essential oils of H. pseudolaeve; trans-caryophyllene (23.92 %), δ-limonene (11.19 %), α-cadinol (10.67 %), caryophyllene oxide (7.96 %), α-pinene (5.76 %), spathulenol (5.21 %) and β-selinene (3.02 %). Fifty-four components were identified in H. thymbrifolium oil, α-pinene (51.31 %), undecane (4.94 %), germacrene D (4.70 %), β-pinene (3.68 %), β-myrcene (3.30 %), spathuleneol (2.92 %) and naphthalane (1.88 %) were determined as the main constituents. Monoterpenes were shown to be the main group of the H. thymbrifolium, while the H. pseudolaeve were more rich in sesquiterpenes. The results have supplied contributions on the usability of oils as renewable resources and chemotaxonomy of plants.
SYNTHESIS AND OPTICAL PROPERTIES OF QUANTUM-SIZE METAL SULFIDE PARTICLES IN AQUEOUS SOLUTION

During the past decade, small-particle' research has become quite popular in various fields of chemistry and physics. The recognition of quantum-size effects in very small colloidal particles has led to renewed interest in this area. Small particles' are clusters of atoms or molecules ranging in size from 1 nm to almost 10 nm or having agglomeration numbers from 10 up to a few hundred. In other words, small particles fall in size between single atoms or molecules and bulk materials. The agglomeration number specifies the number of individual atoms or molecules in a given cluster. The research in this area is interdisciplinary, and it links colloidal science and molecular chemistry. The symbiosis of these two areas of research has revealed some intriguing characteristics of small particles. This experiment illustrates the following: simple colloidal techniques for the preparation of two different types of quantum-size metal sulfide particles; the blue shift of the measured optical absorption spectra when the particle size is decreased in the quantum-size regime; and use of a simple quantum mechanical model to calculate the particle size from the absorption onset measured for CdS.
Drop Distribution Determination in a Liquid-Liquid Dispersion by Image Processing

This paper presents the implementation of an algorithm for automatic identification of drops with different sizes in monochromatic digitized frames of a liquid-liquid chemical process. These image frames were obtained at our Laboratory, using a nonintrusive process, with a digital video camera, a microscope, and an illumination setup from a dispersion of toluene in water within a transparent mixing vessel. In this implementation, we propose a two-phase approach, using a Hough transform that automatically identifies drops in images of the chemical process. This work is a promising starting point for the possibility of performing an automatic drop classification with good results. Our algorithm for the analysis and interpretation of digitized images will be used for the calculation of particle size and shape distributions for modelling liquid-liquid systems.
Formation of Thermoresponsive Gold Nanoparticle/PNIPAAm Hybrids by Surface‐Initiated, Atom Transfer Radical Polymerization in Aqueous Media

We investigated the formation of thermoresponsive gold nanoparticle/poly(N-isopropylacrylamde) (AuNP/ PNIPAAm) core/shell hybrid structures by surface-initiated, atom transfer radical polymerization (SI-ATRP) in aqueous media and the effect of cross-linking on the thermoresponsiveness of the AuNP/PNIPAAm hybrids. The disulfide containing an ATRP initiator was attached onto AuNPs and the monomer, NIPAAm, was polymerized from the surface of AuNPs in the absence or presence of a cross-linker, ethylene diacrylate, in aqueous media at room temperature. The resulting brush-type and cross-linked AuNP/PNIPAAm hybrids were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and variable temperature dynamic light scattering.
Biomimetic Membrane System Composed of a Composite Interpenetrating Hydrogel Film and a Lipid Bilayer

A simple way to form an interpenetrating hydrogel (IPH) by combining a layer‐by‐layer polyelectrolyte membrane with agarose is reported. The formed IPH membrane is more robust and easily manipulated compared to a polyelectrolyte membrane with the same number of layers. The IPH has good diffusion characteristics and retains the advantageous surface charge from the polyectrolyte composition that facilitates the adsorption of a stable lipid bilayer. The stable adsorption of a lipid bilayer on the IPH creates a biomimetic membrane system that is optimized for utilization in a diffusion chamber.
Production of hydrogen via glycerol steam reforming in a Pd‐Ag membrane reactor over Co‐Al2O3 catalyst

Generally, biodiesel fuel, when converted from vegetables oils, produces around 10 wt% of glycerol as a byproduct, which could be used for producing hydrogen by a steam-reforming reaction. Different scientific works have been realized in conventional reactors on the steam reforming of glycerol (GSR) in the aqueous or the gas phase. High reaction pressure and a relatively small catalyst deactivation are noticed when GSR is carried out in an aqueous phase, whereas the catalyst deactivation is the main disadvantage in the gas phase. In this work, GSR reaction was performed in a perm-selective Pd-Ag membrane reactor (MR) packed with a Co-Al2O3 commercial catalyst in order to extract a CO-free hydrogen stream and also enhance the performances in terms of glycerol conversion and hydrogen yield with respect to a traditional reactor (TR), both working at weight hourly space velocity (WHSV) = 1.01 h−1, 400 °C and H2O/C3H8O3 = 6/1. In MR, a maximum glycerol conversion of around 45.0% was achieved at 1.0 bar as reaction pressure, whereas it was around 94% at 4.0 bar. Moreover, as best value, more than 60.0% of CO-free hydrogen recovery was achieved in the MR at 4.0 bar and 22.8 of sweep factor (sweep gas to glycerol ratio). Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Anti-inflammatory Effect of Achyranthoside E Dimethyl Ester in LPS-stimulated RAW 264.7 Cells

Achyranthoside E dimethyl ester (AEDE) is an oleanolic acid glycoside from Achyranthes japonica. In this study, we investigated the effects of AEDE on nitric oxide (NO) production and underlying molecular mechanisms in lipopolysaccharide (LPS)-stimulated macrophages. AEDE inhibited LPS-induced NO secretion as well as inducible NO synthase (iNOS) expression, without affecting cell viability. Further study demonstrated that AEDE induced heme oxygenase-1 (HO-1) gene expression. In addition, the inhibitory effects of AEDE on iNOS expression were abrogated by small interfering RNA-mediated knock-down of HO-1. Moreover, AEDE induced nuclear translocation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor that regulates HO-1 expression. AEDE-induced expression of HO-1 was inhibited by inhibitors of phosphatidylinositol 3-kinase (PI-3K) and extracellular signal regulated kinase (ERK1/2). AEDE phosphorylated Akt and ERK1/2 as well. Therefore, these results suggest that AEDE suppresses the production of pro-inflammatory mediator such as NO by inducing HO-1 expression via PI-3K/Akt/ERK-Nrf2 signaling. These findings provide the scientific rationale for anti-inflammatory therapeutic use of AEDE.
Neutron powder investigation of tetragonal and cubic stabilized zirconia, TZP and CSZ, at temperatures up to 1400 K

A comparative study of tetragonal (Y-TZP, 3 mol% Y 2 O 3 ) and cubic (CSZ, 15 mol% CaO) zirconia powder samples was carried out to learn about a possible structural origin of the superior ionic conductivity of TZP at low temperatures. Structure refinements including anharmonic temperature factors and oxygen occupancies as well as a qualitative analysis of the diffuse background revealed large differences especially of the anisotropy of thermal motion and the underlying disorder in both samples