Miracle-dz/UniFAR-FTUs huggingface dataset:
Adsorption Equilibrium of Isobutane and 1-Butene in Zeolite 13X by Molecular Simulation

Propane−propylene separation is usually done by cryogenic distillation, one of the most energy consuming processes in the chemical industry. Alternative technologies are simulated moving bed (SMB) and vacuum swing adsorption (VSA). In the context of propane−propylene separation by SMB, the choice of suitable desorbents is a key issue. Recent experimental studies on isobutane and 1-butene as desorbents to operate a propane−propylene separation with an SMB, using zeolite 13X as solid adsorbent, motivated the present work. In this paper, the single component adsorption isotherms of isobutane and 1-butene and X−Y diagrams of binary mixtures of the desorbents with propane and propylene in zeolite 13X are computed using a configurational-bias Monte Carlo (CBMC) technique for a temperature range from 333 to 393 K and pressures up to 150 kPa. The interactions between the tertiary sp3 carbon (CH), the sodium cations, and all other atoms of the studied systems have been determined, since no data for these interacti.
Ammonium Nitrogen Movement in a Coarse-Textured Soil Amended with Zeolite

Leaching of NH4 from coarse-textured soils treated with nitrification inhibitors is affected by the soil cation exchange capacity (CEC), the presence of other ions, and the percolation rate. Natural zeolites have unique chemical and physical properties that could enhance the retention of monovalent cations in coarse-textured soils. Column experiments to evaluate NH4 movement in Rositas loamy sand (Typic Torripsamment) amended with erionite (E) or clinoptilolite (K) natural zeolite at rates of 0, 12.5, 25.0 and 50.0 g zeolite kg soil were conducted. Water saturated soil-zeolite mixtures (1.0 kg) received 200 mg NH4-N and were leached with 3.0 liters (150 cm) of deionized water containing a nitrification inhibitor [2-chloro6-(trichloromethyl) pyridine). Total NH4-N leached ranged from 168.4 mg N for the unamended soil (CEC = 29 cmol(+) kg) to 11.6 mg N for the 50.0 g E kg soil (CEC = 102 cmol(+) kg). Total effluent NH4-N at a given amendment rate was less from zeolite E (CEC = 1570 cmol(+) kg) than zeolite K (CEC = 1140 cmol(+) kg). The distribution of NH4 recovered in 5-cm increments was dependent on the CEC of the soil-zeolite mixture. As the CEC increased, the depth of maximum accumulation decreased. These results indicate that zeolites effectively enhanced the retention of NH4 subject to leaching and zeolite application per unit soil volume may be maximized by restricting the depth of incorporation. Additional Index Words: clinoptilolite, erionite, cation exchange capacity, ion selectivity, soil-mixes. View complete article To view this complete article, insert Disc 4 then click button8
Impact of metal work function on memory properties of charge-trap flash memory devices using fowler-nordheim P/E mode

This letter reports the impact of metal work function (/spl Phi//sub M/) on memory properties of charge-trap-Flash memory devices using Fowler-Nordheim program/erase mode. For eliminating electron back tunneling and hole back tunneling through the blocking oxide during an program/erase operation, a gate with /spl Phi//sub M/ of 5.1-5.7 eV on an Al/sub 2/O/sub 3/-SiN-SiO/sub 2/ (ANO) stack is necessary. Compared to a thickness optimized n/sup +/ poly-Si/ONO stack, a high-work-function gate on an ANO stack shows dramatic improvements in retention versus minimum erase state.
Characterization of Pesticide Desorption from Soil by the Isotopic Exchange Technique

The reversibility of pesticide sorption-desorption in soil is of fundamental importance in the understanding of the fate of these agrochemicals in the environment. We used an isotopic exchange method to characterize the irreversibility of the sorption-desorption process of the insecticide imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) and its degradation product imidaclopridurea (1-[(6-chloro-3-pyridinyl)-methyl]-2-imidazolidinone) on a silty clay loam (SiCL) soil, and that of the metabolite imidacloprid-guanidine (1-[6-chloro-3-pyridinyl)methyl]-4,5-dihydro-1H-imidazol-2-amine) on a loamy sand (LS) soil. The exchange between 12 C-pesticide molecules and 14 C-labeled pesticide molecules in soil suspensions preequilibrated for 24 h was monitored and indicated that a fraction of the sorbed chemicals was resistant to desorption. A two-compartment model was applied to describe the experimental sorption data points of the sorption isotherms as the sum of a reversible component and a nondesorbable, irreversible component. The quantitative estimation of the irreversible and reversible components of sorption, experimentally derived from isotopic exchange experiments, indicated degree of irreversibility (percentage irreversibly bound) in the order: imidacloprid-SiCL soil (6-32%) < imidacloprid urea-SiCL soil (15-23%) < imidacloprid guanidine-LS soil (32-51%), with greater irreversibility at lower pesticide concentration. Increasing the preequilibration time and decreasing pH in the imidacloprid-SiCL soil system resulted in increased sorption irreversibility. The irreversible component of sorption determined by the isotopic exchange technique also allowed accurate prediction of the sorption-desorption hysteretic behavior during successive desorption cycles for all three soil-pesticide systems studied. The isotopic exchange technique appears to be a suitable method to quantitatively characterize pesticide desorption from soil, allowing prediction of hysteresis during sorption-desorption experiments.
Study on Acoustic Cavitation and Magnetic Coupling Wax Control Technology

Abstract To solve the wax deposition problem of high-pour-point and high-waxy oil wells, a new acoustic cavitation and magnetic coupling shaft wax control technology was proposed. Experimental research and field tests were conducted. This wax control technology can achieve the purpose of freezing point depression, viscosity reduction by emulsification, and wax control through the combined effect of cavitation, acoustic vibration, and magnetic intensification. Laboratory experiments showed that after acoustic cavitation and magnetic coupling treatment, the viscosity reduction ratio of high-pour-point oil was over 25.5% at 30°C; the freezing point was decreased from 32°C to 27°C, a 15.6% reduction; the wax crystal structure of the oil samples was changed from crude, thick, and dense to fine, thin, and sparse. Field tests showed that the acoustic cavitation and magnetic coupling wax control device can significantly extend the well's wax deposit cycle by more than 30 days and reduce the wax thickness (Yumen Oilfield). Using this technology, the flushing period was extended more than two times, with a maximum up to nine times, and the normal production time was also prolonged (Zhundong Oilfield in Xinjiang). The results are useful for the popularization and application of the new shaft wax control technology for high-freezing-point and high-waxy oil wells.
VISCOSITY OF WATER-OIL EMULSIONS WITH ADDED NANO-SIZE PARTICLES

The viscosity of emulsion and suspensions in the presence of two types of nano-size particles that, have different affinity for oil, have been investigated. It has been found out that both oil-solid suspensions and oil-water-solid mixtures behave as pseudoplastic fluids at all studied solid concentrations. The viscosity of emulsion-solid mixtures does not seem to get affected by water concentration, yet it is a function of solid concentration. The ability of solids to act as emulsifying agents has also been investigated. It has been established that neither of the two types of solids used is capable of stabilizing water-in-oil or oil-in-water emulsions in the absence of surfactants. At low concentrations of solids and in the presence of an oil-soluble surfactant, both oil-wet and water-wet solids, however, are capable of stabilizing water-in-oil emulsions. In the presence of water-soluble surfactant, only water-wet solids are capable of stabilizing oil-in-water emulsions.
Tourmaline of the elbaite-schorl series from the Himalaya Mine, Mesa Grande, California: A detailed investigation

Abstract Chemical, structural, infrared, optical, and Mössbauer spectroscopic data were obtained on tourmalines from gem pockets in the Himalaya mine, San Diego County, California, including a strongly color-zoned crystal. Calcium and Li abundances increase from core to rim, whereas Mn2+ and F increase, reach a maximum, and then decrease. Upon initiation of crystallization of lepidolite, F contents in tourmaline decrease. The black core is a Mn-bearing “oxy-schorl. ” The grayish-yellow, intermediate zone is Mn-rich “fluor-elbaite” that contains a relatively high Mn content with ~6 wt% MnO. The nearly colorless “fluor-elbaite” rim has the highest Li content of all zones. There is an inverse correlation between the lattice parameter a (for values ≥15.84 Å) and the Li content (r2 = 0.96). Mössbauer studies from the different zones within this crystal show that the Fe3+/Fe(total) ratio increases continuously from the Fe-rich core to the Fe-poor near-rim zone, consistent with increasing oxygen fugacity during pegmatite pocket evolution. There is a high positive correlation between lattice parameter a (for values ≥15.84 Å) and (Fe2++Mn2+) content in tourmalines from the elbaite-schorl series (r2 = 0.99). Values lower than 15.84 Å for a are likely a consequence of greater [4]B contents in samples that usually have a (Fe2++Mn2+) content of <0.1 apfu. Positive correlations between Al at the Y site and [4]B (r2 = 0.93), and between (Mn2++Fe2+) and [4]Al (r2 = 0.99) were found in tourmalines from the Himalaya Mine. These correlations indicate that, in the short-range order configurations, YAl is coupled with [4]B, whereas Mn2+ and Fe2+ are coupled with [4]Al. To obtain the most accurate OH data, different analytical methods were used: SIMS, hydrogen manometry, continuous-flow mass spectrometry, and IR overtone spectroscopy. Some elbaites contain a mixed occupation of F, OH, and O at the W site. Based on these data, the assumption OH = 4 - F appears to be valid only for elbaitic tourmalines with FeO+MnO < 8 wt%. In terms of the conditions of formation, whether gel or glass, the transition from low to high viscosity of the pocket-forming medium occurs before primary crystallization within the pockets ceased. At the pocket stage, Li contents of residual hydrosilicate melt were evidently high enough to promote a continuous transition from schorl-foitite at the pegmatite margin to elbaite-rossmanite-liddicoatite in the final stages of consolidation of the pegmatite interior.
Two photon microscopy intravital study of DC-mediated anti-tumor response of NK cells

Recent studies have demonstrated that dendritic cells (DCs) play a crucial role in the activation of Natural Killer cells (NKs) that are responsible for anti-tumor innate immune responses. The focus of this report is on the role of pathogen associated molecular pattern (PAMP) activated-DCs in inducing NK cell-mediated anti-tumor responses. Mice transplanted sub-cute (s.c.) with AK7 cells, a mesothelioma cell line sensitive to NK cell responses, are injected with fluorescent NK cells and DC activation is then induced by s.c. injection of Lipopolysaccharide (LPS). Using 4 dimensional tracking we follow the kinetic behavior of NK cells at the Draining Lymph-Node (DLN). As control, noninflammatory conditions are also evaluated. Our data suggest that NK cells are recruited to the DLN where they can interact with activated-DCs with a peculiar kinetic behavior: short lived interactions interleaved by rarer longer ones. We also found that the changes in the NK dynamic behavior in inflammatory conditions clearly affect relevant motility parameters such as the instantaneous and average velocity and the effective diffusion coefficient. This observation suggests that NK cells and activated-DCs might efficiently interact in the DLN, where cells could be activated. Therefore the interaction between activated-DCs and NK cells in DLN is not only a reality but it may be also crucial for the start of the immune response of the NKs.
Effects of Air-Acetylene Flame Parameters on Simultaneous Multielement Atomic Absorption Spectrometry

The effects of the air-acetylene ratio and the observation height on the detection limits and analytical accuracy of 11 elements (Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn) determined by simultaneous multielement atomic absorption spectrometry with a continuum source (SIMAAC) were investigated. Determinations were made at four observation heights and five airacetylene ratios evenly spaced over normal ranges for these variables. For the 11 elements, detection limits and characteristic concentrations varied by factors of 1.5 to 25. The best compromise detection limits were obtained at observation heights low in the flame and with richer flames. The variations of the analytical recoveries for Co, Cr, Cu, Fe, K, Mg, Na, and Zn determined in a National Bureau of Standards (NBS) standard reference material (SRM) and two United States Geological Survey (USGS) standard rocks as a function of the flame parameters were relatively insignificant. Significant variations were observed for Ca and Mg, whereas the concentration of Ni was too low to permit any conclusions. The optimal, compromise flame parameters, for analytical accuracy, were the two lowest observation heights in lean flames when all elements except Ca and Mg were determined. Inclusion of Mg shifted the optimal parameters to a higher observation height. Four NBS SRM's and three USGS standard rocks were analyzed weekly, over a 7-week period, at a low observation height in a lean air-acetylene flame. In general, accuracies within ±5% of 100% and precisions of ±5% were obtained for Co, Cr, Cu, Fe, K, Mn, Na, and Zn. Acceptable recovery (100% ± 5%) for Ca could only be obtained with a large dilution of the sample into a 0.5% La matrix.
Crystal growth, thermal, optical and microhardness studies of tris (thiourea) zinc sulphate ‐ a semiorganic NLO material

Tris (thiourea) zinc sulphate (ZTS), a semiorganic nonlinear optical (NLO) material has been synthesized at 30 °C. The solubility was determined in different solvents such as water, ethanol and water mixture of ethanol (1:1). Good quality single crystals with size 10 × 8 × 6 mm3 were grown by slow evaporation technique within three weeks with approximate growth rate of 0.5 mm/day. The grown crystals have been subjected to single crystal X‐ray diffraction to determine the unit cell dimensions and morphology. The TGA and DTA reveal that the material has good thermal stability. The UV‐Vis spectrum shows that the material has wide optical transparency in the entire visible region. The second harmonic generation was confirmed by Kurtz powder method. The birefringence of the crystal was measured in the visible region and it was found to vary with the wavelength. The microhardness test was carried out in (100) plane and the load dependent hardness was measured. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative Study between Cubic and non-Cubic Equations of State Using Carnahan-Starling Repulsive Term: Application of Temperature-Dependent Alpha and Beta Functions

Studies on phase equilibria data behavior of pure substances are motivation to the researchers due to importance of these data for the scientific and industrial applications. Several EOS were proposed and its modifications have been made, whose aim is to improve the correlation between experimental and calculated thermophysical properties. This work proposes a comparative study between the PVT calculated data using cubic and non-cubic equations of state, in which its original repulsive term is substituted by the Carnahan-Starling hard-sphere repulsive term; furthermore, generalized expression to calculate (Tr,) and (Tr,) functions are used. Experimental data of vapor pressure for various pure compounds were compared to the calculated vapor pressure data showing satisfactory agreement, when this proposed modification is employed.
Directed Evolution of an Enantioselective Enoate-Reductase: Testing the Utility of Iterative Saturation Mutagenesis

Directed evolution utilizing iterative saturation mutagenesis (ISM) has been applied to the old yellow enzyme homologue YqjM in the quest to broaden its substrate scope, while controlling the enantioselectivity in the bioreduction of a set of substituted cyclopentenone and cyclohexenone derivatives. Guided by the known crystal structure of YqjM, 20 residues were selected as sites for saturation mutagenesis, a pooling strategy based on the method of Phizicky [M. R. Martzen, S. M. McCraith, S. L. Spinelli, F. M. Torres, S. Fields, E. J. Grayhack, E. M. Phizicky, Science 1999, 286, 1153-1155] being used in the GC screening process. The genes of some of the hits were subsequently employed as templates for randomization experiments at the other putative hot spots. Both (R)- and (S)-selective variants were evolved using 3-methylcyclohexenone as the model substrate in the asymmetric bioreduction of the ole-finic functionality, only small mutant libraries and thus minimal screening effort being necessary. Some of the best mutants also proved to be excellent catalysts when testing other prochiral substrates without resorting to additional mutagenesis/screening experiments. Thus, the results constitute an important step forward in generalizing the utility of ISM as an efficient method in laboratory evolution of enzymes as catalysts in organic chemistry.
Monitoring and verification of soil carbon changes under Article 3.4 of the Kyoto Protocol

Abstract. The Marrakech Accords allow biospheric carbon sinks and sources to be included in attempts to meet emission reduction targets for the first commitment period of the Kyoto Protocol. Forest management, cropland management, grazing land management and re‐vegetation are allowable activities under Article 3.4 of the Kyoto Protocol. Soil carbon sinks and sources can therefore be included under these activities. The Kyoto Protocol states that sinks and sources of carbon should be accounted for ‘taking into account uncertainties, transparency in reporting, verifiability’. At its most stringent, verifiability would entail the sampling of each geo‐referenced piece of land subject to an Article 3.4 activity at the beginning and end of a commitment period, using a sampling regime that gives adequate statistical power. Soil and vegetation samples and records would be archived and the data from each piece of land aggregated to produce a national figure. Separate methods would be required to deliver a second set of independent verification data. Such an undertaking at the national level would be prohibitively expensive. At its least stringent, verifiability would entail the reporting of areas under a given practice (without geo‐referencing) and the use of default values for a carbon stock change for each practice, to infer a change for all areas under that practice. A definition of verifiability between these extremes would allow simple methods, such as those derived from IPCC default values for CO2 fluxes from soil, to be used for estimating changes in soil carbon. These may enable low‐level verifiability to be achieved by most parties by the beginning of the first commitment period (2008–2012).
Efficient green emission from transparent Tb3+–silicone hybrid materials

Salicylate complexes of terbium have been modified by co-coordination with trioctylphosphine oxide, by which the complexes can be rendered soluble even in non-polar matrices. Highly transparent, green emitting composites based on rare ions can thus be obtained now by the incorporation of these complexes into silicone matrices, which has in the past been reserved for green emitting organic dyes. The optical properties of the novel hybrid systems have been characterised, showing efficient luminescence of the Tb3+ ions with emission quantum yields of up to 68%.
Solvent isotope effect on ion mobility in water at high pressure. Conductance and transference number of potassium chloride in compressed heavy water

Limiting molar conductances of the K+ and Cl− ions in heavy and light water have been determined at 25 °C as a function of pressure up to 2 kbar from the measured conductances and transference numbers of KCl. The residual friction coefficients (Δζ) are obtained for the cation and the anion in D2O and H2O by using the determined limiting conductance and the bulk viscosity of solvent and compared with the corresponding values predicted by applying the Hubbard–Onsager (HO) dielectric friction theory at various pressures below 1 kbar. At atmospheric and high pressures Δζ of the K+ ion in D2O is larger than that in H2O just as predicted by the HO theory, but Δζ of the Cl− ion in D2O is smaller than that in H2O on the contrary to the theoretical prediction. The reverse solvent isotope effect on Δζ(Cl−) suggests that a microscopic viscosity in the vicinity of the relatively large ion is smaller than the bulk viscosity used in the continuum theory.
Effect of diatomaceous earth on the performance and blood variables of broiler chicks during experimental aflatoxicosis

BACKGROUND: Diatomaceous earth (DE) is a type of tectosilicate found in large quantities in Iran. It is possible that this compound can absorb mycotoxins. An experiment was conducted to evaluate the protective effects of DE on experimental aflatoxicosis in broilers from 1 to 42 days of age. In four treatments of four replicates, 160 one-day-old Hubbard male chicks were subjected to two levels of aflatoxin B1 (AFB1) (0 and 1.0 mg kg−1) and DE (0 and 30 mg kg−1) RESULTS: Body weight gain, feed intake, feed conversion ratio, and productive efficiency index were adversely affected in the chicks treated with AFB1. Weight of heart was significantly decreased (20.3%) by AFB1 (P < 0.05). Serum total protein, albumin, and the activity of serum lactate dehydrogenase (LDH) were decreased by AFB1. DE significantly (P < 0.05) increased body weight gain (9.51%), feed intake (7.44%), and improved feed conversion ratio (2.08%) as well as productive efficiency index (5.48%) in the birds that subjected to AFB1 DE also increased serum albumin (22.6%), and the activity of serum LDH (44.4%). CONCLUSION: DE might be beneficial in reducing toxic effects of AFB1 in broilers. It is possible to include DE as an alternative to other mycotoxin binders at levels of 30 mg kg−1 in the diets on offer to broilers between the ages of 1 and 42 days. Copyright © 2007 Society of Chemical Industry
Empirical modelling using dummy atoms (EMUDA): an alternative approach for studying “auxetic” structures

Auxetics (materials or structures) are systems with a negative Poisson's ratio, a property that arises from the way various geometric features in the structure (or internal structure in the case of materials) deform when subjected to uniaxial loads. Such systems are normally studied by examining the behaviour of idealised representations of structures, which deform in a controlled fashion (e.g. deforming solely through hinging or stretching). Methods used for the analysis typically involve construction of real physical macro-models and/or derivation of analytical expressions for the mechanical properties. This paper proposes an alternative method for analysing such structures whereby idealised “hinging” or “stretching” structures are constructed within a molecular modelling environment using dummy atoms and examined using standard molecular mechanics techniques. We will show that this methodology of “empirical modelling using dummy atoms” (EMUDA) successfully reproduces the known properties of 2D conventional and auxetic hexagonal honeycombs hence confirming the suitability of this technique for studying auxetic structures.