Miracle-dz/UniFAR-FTUs huggingface dataset:
Low‐Level Analysis of Lanthanides in Eleven Silicate Rock Reference Materials by ICP‐MS After Group Separation Using Cation‐Exchange Chromotography

A simple method is described for the determination of lanthanides in depleted rocks based on acid dissolution, cation-exchange chromatography and ICP-MS analysis using a low flow, microconcentric nebuliser. The potential of the method is evaluated by analysis in triplicate of eleven low-concentration level geochemical reference materials (UB-N, NIM-D, BIR-1, DNC-1, JB-2, JGb-1, JGb-2, NIM-N, NIM-P, FK-N and MA-N). The repeatability of the three dissolutions is between 0.2% and 0.6% relative standard deviation (RSD) for basaltic samples BIR-1 and JB-2, with the exception of La in BIR-1 (2.6% RSD), presumably because of blank or memory effects. The results are more scattered for coarsegrained rocks. A good agreement between the results and working values is observed for most mafic samples and the serpentinite UB-N. Significant deviations observed between the data obtained in this work and working values for some reference materials might reflect heterogeneities of the REE distributions in coarse-grained (especially granitic) rocks at the 10 0 mg sub-sampling scale. Ce travail presente une methode simple pour le dosage des lanthanides dans les roches appauvries, basee sur une attaque acide, la separation des analytes sur colonne echangeuse de cations et leur dosage par spectrumeatrie de masse a source plasma ICP, a l'aide d'un micro-nebuliseur concentrique a faible debit. Les possibilityes de cette methode sont evaluees gracce a lanalyse en triple de onze materiaux de reference geochimiques sa faible teneurs (UB-N, NIM-D, BIR-1, DNC-1, JB-2, JGb-1, JGb-2, NIM-N, NIM-P, FK-N et MA-N). La repetabilite sur les trois dissolutions est comprise entre 0.2% et 0.6% (ecart type relatif) pour les etalons de nature basaltique BIR-1 et JB-2, a l'exception du lanthane dans BIR-1 (2.6% ETR), probablement a cause des effets de memoire instrumentale ou de problemes de blancs. Les resultats sont davantage disperses pour les roches a gros grain. On observe un bon accord entre les valeurs generalement admises et les resultats obtenus pour la plupart des echantillons mafiques et la serpentinite UB-N. Les ecarts significatifs observes pour certains materiaux de reference pourraient etre attribues a une distribution inhomogene des ralements du groupe des terres rares dans les roches grenues, en particulier granitiques, a l'echelle de prelevement (100 mg) utilisee pour ce travail.
A Comparative Simulation Study on Oxidative Coupling of Methane in Fixed-Bed and Membrane Reactors

Oxidative coupling of methane (OCM) on a conventional fixed-bed reactor (FBR) and a ceramic dense membrane reactor (DMR) packed with Li/MgO catalyst is analyzed using plug-flow reactor models. The validity of OCM kinetic equations employed in the modeling is confirmed by excellent agreement between the simulation and experimental data for OCM on FBR. For FBR, a high methane to oxygen feed ratio favors the OCM reaction, with a low C2 yield because of insufficient oxygen supply. The highest C2 yield achieved with a feed mixture consisting of 70% methane and 30% oxygen is 20.7% at a selectivity of 53% and operating temperature of 750 °C. The C2 yield and selectivity increase slightly at a higher operating temperature. The optimal feed ratio does not change with temperature. DMR is made of a mixed-conducting ceramic membrane tube packed with an OCM catalyst. The membrane tube separates the methane and oxygen feed. The oxygen concentration in the DMR is much lower and more uniform than that in the FBR because .
The Use of WeChat Application on CFL Learners' Vocabulary Acquisition.

This quasi-experimental research explored Chinese as a Foreign Language (CFL) learners’ use of a popular social networking application in China, WeChat, in acquiring vocabulary. The research questions answered in this study are: (1) How may the CFL learners’ vocabulary performance be described in terms of: (a) pretest scores and (b) posttest scores; (2) Is there a significant difference between the performance in pretest and posttest of the control group and experimental group? ; (3) What are the implications of the results of this study in teaching? Participants joined the ten-day treatment wherein they used the three features of WeChat: WeChat Messaging, Official Accounts, and Mini Programs. The participants’ performance before and after the treatment were identified using pretest and posttest. In addition, observation checklists were utilized to determine the change in behavior in acquiring vocabulary of the CFL learners. Results suggested that WeChat could improve students’ vocabulary acquisition in foreign language. Suggestions for improvements in future WeChat treatment were also discussed.
Synthesis of 3‐Alkyl and Arylapomorphines

Abstract The synthesis of 3‐alkyl and arylapomorphines 18–20 has been accomplished by using the Suzuki–Miyaura cross‐coupling reaction of vinyl‐ and allylhalide morphinanedienes or arylhalide apocodeines and arylboronic acids.
Development and Laboratory Performance Evaluation of a Variable Configuration PM1/PM2.5 Impaction-Based Sampler

This study presents the design and lab evaluation of a compact medium flow multiple round nozzle-based inertial impactor with variable head for collecting particulate matter (PM). The impactor operates at a flow rate of 175 LPM and consists of two different sets of circular acceleration nozzles designed for PM2.5 (particle aerodynamic diameter < 2.5 µm) and PM1 (particle aerodynamic diameter < 1 µm), either of them could be used at a time as per the objective of sampling. High vacuum grade silicone grease is used as an impaction substrate. Lab experiments were performed using a polydisperse dolomite powder as test aerosol. The nozzle configurations selected were such that the first one provides a 50% cutpoint at 2.50 µm (aerodynamic diameter) with a pressure drop of 0.35 kPa while the second one produces a 50% cutpoint at 1.06 µm (aerodynamic diameter) with a pressure drop of 1.07 kPa. Particle losses through the nozzles were low for particle diameter upto 5.0 µm. Particle bounce-off and re-entrainment losses were found to be insignificant. Owing to its higher flow rate, it has an advantage of collecting appreciable quantity of particles (and higher number of samples) in a relatively smaller time frame as compared to other low flow rate samplers. The samples can be analyzed to obtain finely time-resolved aerosol composition which can help in a better understanding of the role of various physico-chemical processes active during different meteorological conditions (extreme dust and foggy events) that affect fate and transport of PM, especially in the Indo-Gangetic plain (IGP).
A preliminary evaluation of the relationship between bioconcentration and hydrophobicity for surfactants

A statistical analysis was done of the relationship between hydrophobicity and bioconcentration parameters (uptake and elimination rate constants and bioconcentration factor) predicted by the diffusive mass-transfer (DMT) concept of bioconcentration developed previously. We employed polychlorinated biphenyls and benzenes (PCB/zs) as model compounds and the octanol/water partition coefficient as hydrophobicity parameter. We conclude that the model is consistent with the data. Subsequently, we applied the DMT concept to a set of preliminary bioconcentration data for surfactants using the critical micelle concentration (CMC) as hydrophobicity parameter. The obtained relationships qualitatively agree with the DMT concept, indicating that hydrophobicity is of great influence on surfactant bioconcentration. Finally, we investigated the hydrophobicity-bioconcentration relationships of surfactants and PCB/zs using aqueous solubility as common hydrophobicity parameter and found the relationships between the bioconcentration parameters and hydrophobicity to agree with the DMT concept. These findings are based on total radiolabel data. Therefore, they need to be confirmed using compound-specific surfactant bioconcentration data.
Ultrasound-assisted extraction of virgin olive oil to improve the process efficiency

Malaxation is a basic step in the mechanical olive oil extraction process that may affect yield, quality, and health properties of virgin olive oil (VOO). The operative conditions of malaxation, such as temperature and time, are fundamental to favor the oil coalescence process and, consequently, the duration of the VOO extraction process. The aim of this study was to improve the extraction process efficiency by using an ultrasound treatment of olive paste before the malaxation step. The ultrasonic treatment was applied to Coratina and Peranzana, which are two of the most popular Southern Italian olive varieties characterized by extremely different technological performance. Different times of ultrasound treatments were tested (0, 2, 4, 6, 8, 10 min) and free acidity, peroxide value, K232, K270, sensory analysis, tocopherols, total carotenoids, chlorophyll, and total polyphenols were determined. Results showed that the ultrasound treatment caused a quick heating of the olive paste as a function of the ultrasound treatment time. Times of treatment of 8 and 10 min allowed the reduction of the malaxation phase from 60 to about 40 min. The ultrasound technique improved antioxidant content in both VVOs, except for polyphenols that decreased. However, the reduction of polyphenol concentration in Coratina VOO improved its taste by reducing the bitter and pungent notes, which are not always accepted by consumers. Practical applications: In this study we propose an innovative application of ultrasound in VOO processing. Ultrasound treatment was applied to olive paste before malaxation in order to increase the process efficiency by reducing the malaxation step. Further, this strategy makes it possible to reduce the number of kneaders, thus reducing the plant costs. The resulting VOO after the ultrasound treatment presents a more harmonic taste and an appealing and desirable color when applied to a variety notoriously characterized by strong bitter and pungent notes such as Coratina, making the oil more attractive for consumers with respect to the traditional ones.
Global boundedness of solutions to the two-dimensional forager-exploiter model with logistic source

This paper deals with the global boundedness of solutions to the forager-exploiter model with logistic sources \begin{document}$ \begin{equation*} \left\{ \begin{array}{lll} u_t = \Delta u- \nabla\cdot(u\nabla w) + \mu_1 (u-u^m), x'>under homogeneous Neumann boundary conditions in a smoothly bounded domain \begin{document}$ \Omega \subset R^2 $\end{document} , where the constants \begin{document}$ \mu $\end{document} , \begin{document}$ \mu_1 $\end{document} , \begin{document}$ \mu_2 $\end{document} , \begin{document}$ \lambda $\end{document} , \begin{document}$ m $\end{document} and \begin{document}$ l $\end{document} are positive. We prove that the corresponding initial-boundary value problem possesses a global classical solution that is uniformly bounded under conditions \begin{document}$ 2\leq m , \begin{document}$ l \geq 3 $\end{document} , \begin{document}$ r(x,t) \in C^1(\overline{\Omega}\times[0,\infty))\cup L^{\infty}(\Omega\times(0,\infty)) $\end{document} and the smooth nonnegative initial functions, which improves the results obtained by Wang and Wang (MMMAS 2020).
Reactions on polymers with amine groups. I. Reactions of vinylpridine polymers and of their model compounds with unsaturated carboxylic acids

The reactions of vinylpyridine polymers with α,β-unsaturated carboxylic acids such as acrylic, methacrylic, crotonic, itaconic, cinnamic, fumaric, and maleic acids were studied. It was found that, when reacted with acrylic, itaconic and fumaric acids. poly(4-vinylpyridine) gave macromolecular betaine products while with maleic acid, betaine as well as the corresponding salt was obtained. Poly(2-vinylpyridine) reacted with the same acids as poly(4-vinylpyridine) gave only the salts. No significant changes were observed with the two polymers when reacted with methacrylic, crotonic, and cinnamic acids. To attempt to rationalize these observations with the two macromolecular tertiary amines, the reactions of 4-methyl and 2-methylpyridines with the same carboxylic acids were investigated. The 1H-NMR methodology was generally applied to elucidate the chemical structure obtained. © 1995 John Wiley & Sons, Inc.
Multi-Jet Mode Electrospray for Non-Conducting Fluids Using Two Fluids and a Coaxial Grooved Nozzle

The development of electrospray technique is restricted due to main drawbacks, mainly because it is restricted to electrically conducting liquids and to low throughputs. To overcome these limitations, we have developed a multi-jet electrospray technique for non-conducting fluids. To obtain stable multi-jet operation, a grooved coaxial nozzle was employed to enhance the exterior electrical field. The multi-jet coaxial electrospray mechanism is identical to a single cone-jet coaxial electrospray, and multi-jet operation for a non-conducting fluid has the same features as a single cone-jet for a conducting liquid. The droplet size can be controlled by adjusting the flow rates, and the droplets monodisperse with good stability and uniformity.
Coarsening in Sintering: Grain Shape Distribution, Grain Size Distribution, and Grain Growth Kinetics in Solid-Pore Systems

Sintering occurs when packed particles are heated to a temperature where there is sufficient atomic motion to grow bonds between the particles. The conditions that induce sintering depend on the material, its melting temperature, particle size, and a host of processing variables. It is common for sintering to produce a dimensional change, typically shrinkage, where the powder compact densifies, leading to significant strengthening. Microstructure coarsening is inherent to sintering, most evident as grain growth, but it is common for pore growth to occur as density increases. During coarsening, the grain structure converges to a self-similar character seen in both the grain shape distribution and grain size distribution. Coarsening behavior during sintering conforms to classic grain growth kinetics, modified to reflect the evolving microstructure. These modifications involve the grain boundary coverage due to pores, liquid films, or second phases and the altered grain boundary mobility due to these phases. The mass transport rates associated with each of these interfaces are different, with different temperature and composition dependencies. Hence, the coarsening rate during sintering is not constant, but changes with the evolving microstructure. Core aspects treated in this review include models for coarsening, grain shape, grain size distribution, and how pores, liquids, dispersoids, and other phases determine microstructure coarsening during sintering.
Redox chromatography using polypyrrole as a stationary phase

Abstract Chromatographic studies on the effect of exposure of polypyrrole coated stationary phases to redox reagents have been carried out. Polypyrrole containing chloride or dodecylsulfate as counterion was chemically synthesized and coated onto silica particles and packed into a chromatographic column. A series of standard compounds was used as the molecular probes. Changes in the chromatographic properties of polypyrrole as the result of the exposure to redox reagents were compared with those obtained by electrochemical treatment.
Effects of Lactobacillus rhamnosus GG addition in ice cream

A 24 full factorial experimental design was applied to verify the effects of Lactobacillus rhamnosus GG (LGG) addition in retail-manufactured ice cream stored at two different freezing temperatures (-16°C and -28°C) and containing two different levels of sugar (15-22%) and fat (5-10%). In addition to microbial counts, the pH, acidity, viscosity of the mixes and functional properties of the ice creams were evaluated. Both fresh and frozen-thawed LGG cells underwent preliminary resistance tests to bile, antibiotics and acidity. The LGG strain proved to be highly resistant to most of the stress factors. When the micro-organism was added to ice cream mixes in a quantity of 10 8 cfu/g, it did not change the overrun, firmness or melting behaviour of the finished product. Regardless of formulation, no count decay of LGG cells was observed in ice cream stored for up to 1 year.
XPS analysis of sorption of selenium(IV) and selenium(VI) to mackinawite (FeS)

The Se 3d XPS spectra showed evidence of reduction of Se(IV) by contact with the mackinawite surface when certain assumptions were made, but there was no clear evidence for reduction of Se(VI). A continuous oxidation of surface Fe(II) was observed for FeS in contact with Se(IV), as indicated by a decrease of intensities of Fe(II)‐S XPS peaks. S 2p spectra showed some evidence of oxidation of surface S(‐II) associated with Se reduction that resulted in formation of polysulfides. However, the apparent change in S 2p spectra could be the result of overlap between S 2p and Se 3p peaks. FeS particles became red and attached to the wall of reaction vessels within 3–4 days after contact with Se(IV), suggesting that a new solid‐phase, possibly Se(0), may have been produced. The low signal‐to‐noise of the S 2p peaks observed after 15 and 30 days contact with Se indicates increased amounts of sulfur in solution. This supports the existence of a reaction of Se with FeS in which discrete precipitates are formed and sulfide is released to solution. These observations support the conclusion that Se(IV) sorbs onto the surface of FeS and oxidizes surface species of iron and sulfur. © 2011 American Institute of Chemical Engineers Environ Prog, 32: 84–93, 2013.
Crystal Structure of Tetramethylammonium-Exchanged Vermiculite

Vermiculite crystals from Santa Olalla, Spain, were intercalated with tetramethylammonium (TMA) after Na saturation. The resulting TMA-vermiculite showed near perfect 3-dimensional stacking order with cell parameters of a = 5.353(1) Å, b = 9.273(2) Å, c = 13.616(6) Å, β = 97.68(3)°, and space group C2/m, which indicated a 1M polytype. Single crystal X-ray refinement (R = 0.073, wR = 0.082) located the central atom (N) of the TMA (occupancy at 0.418) and the C atom of 1 methyl group (occupancy at about 0.35). The TMA is offset from the center plane between 2 silicate layers by 1.52 Å, and the methyl group is keyed into the silicate ring of the adjacent silicate layer. This arrangement constrains the positions of the C atoms of the other methyl groups to an opposing plane parallel to the oxygen basal plane. Associated H2O is randomly located between the TMA pillars, and no scattering from these molecules was observed. The calculated height of the TMA molecule is shown to be 4.15 Å. Steric and electrostatic arguments suggesting that adjacent TMA molecules must alternate apex directions (±c) allow for a description of the local TMA arrangement. This model involves the keying of TMA molecules laterally, thereby explaining why perfect 3-dimensional stacking occurs. The offset of TMA from the center of the interlayer region produces a cavity suitable as an adsorption site for small molecules, such as benzene, which is consistent with the higher than expected adsorption of these molecules in TMA-smectites of high layer charge. This offset also explains the easy expandability of TMA-clays, since only very weak interactions occur between TMA and 1 adjacent silicate layer, thereby allowing molecules to enter the interlayer.
EFFECT OF POSTMORTEM CONDITIONS ON CERTAIN CHEMICAL, MORPHOLOGICAL AND ORGANOLEPTIC PROPERTIES OF BOVINE MUSCLE

Paired sides from U.S. Choice grade beef were aged immediately after slaughter at 2 and 16°C. Samples were removed from longissimus and semitendinosus at slaughter and at 1, 3 and 7 days postmortem for ATPase assay, phase microscopy, shear and organoleptic evaluation. Rib steaks from sides aged at 16°C for 1-day postmortem were as tender as steaks from sides aged at 2°C for 7 days postmortem. Flavor development of rib steaks also was more rapid at 16°C than at 2°C. Tenderness of semitendinosus steaks was improved by aging sides at 16°C; the difference in improvement of tenderness of semitendinosus, however, was not as great between 2°nd 16° as it was for rib steaks. Ca++, Mg++ and EGTA-modified ATPase activity of myofibrils from both muscles increased with postmortem time, with myofibrils from muscles held at 16°C having slightly higher ATPase activity than myofibrils from muscles held at 2° Increased EGTA-modified ATPase activity was indicative of loss of calcium sensitivity of the myofibril. Sarcomeres of myofibrils from longissimus were longer at 1-day postmortem than those from at-death longissimus and they remained essentially unchanged during the remainder of postmortem aging; however, tenderness improved at 16°C for 1 day and at 2°C for 3 days. Also greater fragmentation of myofibrils from longissimus postmortem aged at 16°C for 1 day and at 2°C for 3 days was observed, suggesting that the rate of myofibril fragmentation is an important factor in tenderization.
Modelling soil compaction impacts on nitrous oxide emissions in arable fields

Nitrous oxide (N2O) emissions comprise the major share of agriculture's contribution to greenhouse gases; however, our understanding of what is actually happening in the field remains incomplete, especially concerning the multiple interactions between agricultural practices and N2O emissions. Soil compaction induces major changes in the soil structure and the key variables controlling N2O emissions. Our objective was to analyse the ability of a process‐based model (Nitrous Oxide Emissions (NOE)) to simulate the impact of soil compaction on N2O emission kinetics obtained from field experiments. We used automatic chambers to continuously monitor N2O and CO2 emissions on uncompacted and compacted areas in sugar beet fields during 2 years. Soil compaction led to smaller CO2 emissions and larger N2O emissions by inducing anoxic conditions favourable for denitrification. Cumulative N2O emissions during the crop cycles were 944 and 977 g N ha−1 in uncompacted plots and 1448 and 1382 g N ha−1 in compacted plots in 2007 and 2008, respectively. The NOE model ( Hénault et al., 2005 ) simulated 106 and 138 g N2O‐N ha−1 in uncompacted plots and 1550 and 650 g N2O‐N ha−1 in compacted plots in 2007 and 2008, respectively, markedly under‐estimating the nitrification rates and associated N2O emissions. We modified the model on the basis of published results in order to better simulate nitrification and account for varying N2O fractions of total end‐products in response to varying soil water and nitrate contents. The modified model (NOE2) better predicted nitrification rates and N2O emissions following fertilizer addition. Using a fine vertical separation of soil layers of configurable, but constant, thickness (1 cm) also improved the simulations. NOE2 predicted 428 and 416 g N‐N2O ha−1 in uncompacted plots and 1559 and 1032 g N‐ N2O ha−1 in compacted plots in 2007 and 2008, respectively. These results show that a simple process‐based model can be used to predict successfully the post‐fertilizer addition kinetics of N2O emissions and the impact of soil compaction on these emissions. However, large emissions later on during the cropping cycle were not captured by the model, emphasizing the need for further research.