Miracle-dz/UniFAR-FTUs huggingface dataset:
NO Reduction by Activated Carbons. 4. Catalysis by Calcium

The effect of calcium as catalyst of the NO-carbon reaction has been investigated. Three carbons of different origin and surface properties were loaded by ion exchange with calcium acetate. The effect of catalyst loading was also investigated in one of the carbons. The samples were characterized by physical adsorption of CO 2 (at 0 o C) and N 2 (at -196 o C) and by chemisorption of CO 2 at 300 o C. The NO-carbon reaction was studied in a fixed-bed flow reactor at atmospheric pressure using two types of experiments: (i) temperature-programmed reaction in a NO/He mixture; and (ii) isothermal reaction at 300-600 o C. The reaction products were monitored in both cases, thus allowing detailed oxygen and nitrogen balances to be determined. Calcium was found to catalyze NO reduction by carbon through a mechanism that is consistent with the formation of intermediate CaO(O surface species. Nevertheless, the calcium species present on the carbon surface before NO reduction (CaO) are much less effective than the potassium species (elemental potassium or potassium suboxide) in chemisorbing NO, as a result of which they transfer much less oxygen to the carbon active sites. The results show also that the porous structure and the surface chemistry of the carbon determine, in a complex way, the catalyst loading and dispersion, as well as the catalyst/substrate contact, and hence control the catalytic activity of calcium in NO reduction by carbon
Magnesium fixation—a possible cause of negative yield responses to lime applications

Abstract Negative yield responses are common when highly leached soils are limed to neutrality. A number of explanations have been proposed, but very few have been experimentally verified or are entirely acceptable. In this paper the problem is re‐examined and a new possible causal mechanism is proposed. Data assembled from the literature are used to demonstrate that a consistently observed reduction in Mg uptake by plants when soils are limed to neutrality is often accompanied by a generally ignored reduction in exchangeable soil Mg. Using data for soils of North American and African origin, it is demonstrated that when the soils were limed with pure Ca sources, the level of exchangeable soil Mg was reduced between 36 and 93%. Furthermore, after treatment with a Mg containing liming material, initial increases in the level of exchangeable Mg were followed by similarly large decreases when the soil pH approaches neutrality. The applicability of known Mg fixation mechanisms is briefly discussed and the sug.
Antimicrobial activity and essential oil composition of Thymus daenensis Celak from Iran

The composition and antimicrobial activity of the essential oil of Thymus daenensis Wild, an endemic species from Iran, was studied. The volatile oil obtained by hydrodistillation was characterized by the physico-chemical properties, gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) techniques. Thirty compounds, accounting for 97.5% of the total oil, were identified. The main constituents were thymol (29.8%) and carvacrol (13.6%), p-cymene (11.3), borneol (6.8%) and 1, 8cineole (5.89%). The antimicrobial activity of essential oil of T. daenensis was tested against two Gramnegative and Gram-positive bacteria and three fungi by disc diffusion method. The results of the bioassays showed the interesting antimicrobial activity, in which the Gram-positive bacteria, Staphylococcus aureus, was the most sensitive to the oil, as well the oil exhibited a remarkable antifungal activity against all the tested fungi. These results confirm the possibility of using T. daenensis in food system, medicine and pharmacy.
Effect of crop rotations and fertilization on soil organic matter and some biochemical properties of a thick Black Chernozem

The effects of crop rotation and various cultural practices on soil organic matter and some biochemical characteristics of a heavy-textured, Orthic Black Chernozem with a thick A horizon were determined after 31 yr at Melfort, Saskatchewan. Treatments investigated included: fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crops in predominantly spring wheat (Triticum aestivum L.) systems. The results showed that neither soil organic C nor N in the top 15 cm of soil, nor hydrolyzable amino acids, nor C mineralized in 14 d at 20 °C were influenced by fertilization. However, the relative molar distribution (RMD) of the amino acids reflected the influence of fertilization and the phase (Rot-yr) of the legume green manure rotation sampled. Some characteristics assessed increased marginally with increasing cropping frequency but differences were less marked than results obtained earlier in a heavy-textured Black Chernozem with a thin A horizon at Indian Head, Saskatchewan. Th.
Applicability of a Model Predicting Iodine-129 Profile in a Silver Nitrate Silica-Gel Column for Dissolver Off-Gas Treatment of Fuel Reprocessing

The applicability of a mathematical model predicting iodine-129 profile in a silver nitrate silica-gel (hereinafter referred to as Ag-S) column for radioactive iodine treatment was examined using actual off-gas from a dissolution step of a spent nuclear fuel reprocessing test rig, where PWR spent fuels with burnups up to 44,000 MWdt−1 were dissolved. The iodine-129 profile predicted by the model showed good agreement with the iodine profile obtained in the experiment. It was suggested that the model would be useful to predict iodine profiles in an Ag-S column operated at 423 K for the off-gas treatment of actual spent fuel dissolution. Also, the values of the parameters used in the prediction, i.e., the effective diffusion coefficient and the Langmuir coefficient, were supposed to be applicable within the volumetric NO2 concentration range lower than 1%.
Specular neutron reflection at the mica/water interface – irreversible adsorption of a cationic dichain surfactant

Neutron reflection from the important mineral mica at the solid/liquid interface is presented here using a new approach – a very thin mica crystal supported on a silicon substrate. This approach avoids the problems of crystal defects and surface undulations that have hindered previous work. The use of mica as a reflectivity substrate is important as it is a model surface, which is atomically smooth with a high structural charge. In this work the mica/water interface is fully characterized. In particular, a characteristic double critical edge is observed, arising from the higher scattering length densities of the mica and D2O subphase relative to the silicon support. The experimental data are modelled using a combined approach: conventional amplitude summation (matrix method) for the thin layers and reflected intensity summation with attenuation terms for the thick layers of mica and hydrocarbon adhesive. Reflection data from the adsorption of the dichain cationic surfactant didodecyldimethylammonium bromide (DDAB) to the surface of muscovite mica from aqueous solution are also presented. It is found that, at twice the critical micelle concentration, a bilayer of DDAB with a thickness of 24 A is observed, containing essentially no water. Its partial removal by washing and ion exchange is also presented.
High‐Density Carrier Accumulation in ZnO Field‐Effect Transistors Gated by Electric Double Layers of Ionic Liquids

Very recently, electric‐field‐induced superconductivity in an insulator was realized by tuning charge carrier to a high density level (1 × 1014 cm−2). To increase the maximum attainable carrier density for electrostatic tuning of electronic states in semiconductor field‐effect transistors is a hot issue but a big challenge. Here, ultrahigh density carrier accumulation is reported, in particular at low temperature, in a ZnO field‐effect transistor gated by electric double layers of ionic liquid (IL). This transistor, called an electric double layer transistor (EDLT), is found to exhibit very high transconductance and an ultrahigh carrier density in a fast, reversible, and reproducible manner. The room temperature capacitance of EDLTs is found to be as large as 34 µF cm−2, deduced from Hall‐effect measurements, and is mainly responsible for the carrier density modulation in a very wide range. Importantly, the IL dielectric, with a supercooling property, is found to have charge‐accumulation capability even at low temperatures, reaching an ultrahigh carrier density of 8×1014 cm−2 at 220 K and maintaining a density of 5.5×1014 cm−2 at 1.8 K. This high carrier density of EDLTs is of great importance not only in practical device applications but also in fundamental research; for example, in the search for novel electronic phenomena, such as superconductivity, in oxide systems.
Calculation of x-ray fluorescence intensities from bulk and multilayer samples

Equations are derived for the calculation of x-ray fluorescence intensities from bulk and multilayer samples. Both intra- and interlayer secondary fluorescence intensities are expressed analytically, in terms of the exponential-integral function. It is shown that calculations are performed much faster with this method than with a previous method using numerical integration. As an illustration, some examples of intensity calculations are given for a thin layer on a substrate.
Chemical Linkage of Polysaccharides to Residual Lignin in Loblolly Pine Kraft Pulps

Abstract The chemical bonding of polysaccharides to the residual lignin remaining in bleachable grade loblolly pine (Pinus taeda) kraft pulp was examined by methylation analysis. Before analysis, most of the nonbonded polysaccharides were enzymatically hydrolyzed and the sugars were washed from the remaining solid to give a residual lignin that contained about 8% carbohydrates. The analysis indicated that the majority of the remaining sugars were present as oligomeric segments of well-characterized pulp polysaccharides. About one monomeric unit per oligomer was bonded to lignin. The methylation data indicated that the major bonding was to the primary C-6 position in hexans and the primary C-5 position in arabinan. Xylan was bonded to lignin at C-3 with a small amount at C-2. The overall pattern and quantity of bonding was sufficiently similar to that previously determined for Pinus taeda wood to conclude that formation of alkali-stable, acid-hydrolyzable lignin-carbohydrate bonds is not significant during.
Auxin treatment of pre‐veraison grape (Vitis vinifera L.) berries both delays ripening and increases the synchronicity of sugar accumulation

Background and Aims: Pre-veraison auxin treatments can delay grape berry ripening, but there is little information about their effects on berry development and wine composition. The aim of this study was to further investigate these effects and explore the practical implications of delaying ripening. Methods and Results: Treatment of pre-veraison Vitis vinifera L. cv. Shiraz berries with 1-naphthaleneacetic acid (NAA) significantly delayed ripening as measured by the accumulation of total soluble solids (TSS) and anthocyanins. The onset of the post-veraison phase of berry size increase was delayed in NAA-treated fruit, but these fruit were significantly larger than Control fruit at harvest. NAA-treatments significantly increased the synchronicity of berry sugar accumulation. GC-MS analysis of wine headspace volatiles showed significant, but largely small, differences in the concentration of 19 compounds. No significant difference in sensory properties was found between replicate small-scale wine lots made from Control and NAA-treated fruit. Conclusions: Auxin treatment delayed berry ripening, increased the synchronicity of sugar accumulation between berries, increased berry size and changed the levels of some volatile compounds, but did not affect wine sensory properties. Significance of the Study: We propose that NAA sprays might be used to delay grape berry ripening and increase the synchronicity of sugar accumulation, and therefore ripening, without deleterious effects on wine quality. This may be useful in controlling winery intake and fruit composition.
Formation of self-assembled monolayers by chemisorption of derivatives of oligo(ethylene glycol) of structure HS(CH2)11(OCH2CH2)mOH on gold

This paper describes the preparation of oligo(ethylene glycol)-terminated alkanethiols having structure HS- (CHz)'l(OCH2CHz),nOH (m = 3-7) and their use in the formation of self-assembled monolayers (SAMs) on gold. A combination of experimental evidence derived from X-ray photoelectron sp€ctroscopy (XPS), measurement of contact angles, and ellipsometry implies substantial disorder in the oligo(ethylene glycol)-containing segment. The order in the -(CHz)r- group is not defined by the available evidence. The SAMs are moderately hydrophilic: du(H2O) = 34-38o; d,(H2O) = 22-25". A study of monolayers containing mixtures of HS(CH2)rrCHr and HS(CH2)rr(OCH2CH 2)6OH suggests that the oligo(ethylene glycol) moieties are eflective at preventing underlying methylene groups from influencing wetting by water. A limited study demonstrates that these oligo(ethylene glycol)-containing SAMs resist the adsorption of protein from solution and suggests that SAMs will be a useful model system for studying the adsorption of proteins onto organic surfaces.
Highly fouling resistant ultrafiltration membranes for water and wastewater treatments

Control of fouling is a critical issue to increase the competitiveness of ultrafiltration (UF) membranes for drinking water and wastewater treatments. Highly fouling resistant UF membranes synthesized by photo-graft copolymerization of a water soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a polyethersulfone UF membrane have been evaluated with respect to the adsorptive as well as the ultrafiltration fouling. Protein, humic substance and polysaccharide solutions were used as the model for foulants occurring in the water sources for drinking water as well as in wastewater effluents. The results show that the modified membranes exhibited a much higher fouling resistance for all foulants than the unmodified membranes. Their combined high fouling resistance and high rejection suggests that the obtained modified membranes are very promising as a new generation of thin-layer composite low fouling UF membranes for drinking water and wastewater treatment applications.
Constituents of the Essential Oil from Leaves and Seeds of Blepharocalyx tweediei (Hook, et Arn.) Berg and B. gigantea Lillo

Abstract The composition of the essential oils from leaves and seeds ofBlepharocalyx tweediei and B. gigantea, two closely related taxa from Argentina, was determined by capillary GC, GC/MS and 13C-NMR. The main compounds in the oils of B. tweediei were α-and β-pinene, 1,8-cineole and limonene, linalool being also a major constituent of the oil from leaves. The oils from B. gigantea were characterized by a high percentage of 1,8-cineole, followed by β-pinene and viridiflorol.
Short time electron cyclotron resonance hydrogenation of polycrystalline silicon thin‐film transistor structures

Electron cyclotron resonance plasmas have been used to produce the most effective, shortest time plasma hydrogenation of thin‐film polycrystalline silicon transistors yet reported. We demonstrate that significant improvement in device characteristics can be achieved with these plasmas using exposure times of the order of only 1 min and that 5 min exposures give saturated characteristics of a 2 V threshold voltage, a 65 cm2/V s mobility, and a 107 on/off ratio. We also explore the pressure and power level dependence of this passivation, as well as the effects of shielding with a grid, and show that the more efficient and more stable electron cyclotron resonance hydrogen exposures are at lower pressures.
Conformational characterization of a maleic acid copolymer with an inflexible side chain

ABSTRACT Viscometric, pH, optical, and calorimetric titration studies of an alternating copolymer of maleic acid and indene in aqueous NaCl of 0.01 to 0.27 M at 15 to 35°C showed the conformational transition of a compact to an expanded coil upon ionization of the primary carboxyl groups. the thermodynamic parameters of the transition were calculated. the results indicate that the bulky and inflexible side chain in indene sterically interferes with the formation of the compact form of the copolymer, but stabilizes the low entropic hydrophobic region.
Probing the Enzymatic Activity of Alkaline Phosphatase within Quantum Dot Bioconjugates

Enzymes provide the critical means by which to catalyze almost all biological reactions in a controlled manner. Methods to harness and exploit their properties are of strong current interest to the growing field of biotechnology. In contrast to depending upon recombinant genetic approaches, a growing body of evidence suggests that apparent enzymatic activity can be enhanced when located at a nanoparticle interface. We use semiconductor quantum dots (QDs) as a well-defined and easily bioconjugated nanoparticle along with Escherichia coli-derived alkaline phosphatase (AP) as a prototypical enzyme to seek evidence for this process in a de novo model system. We began by first assessing whether the relatively large dimeric AP protein (∼100 kDa) can be assembled onto two differentially sized green and red CdSe/ZnS core/shell QDs in a ratiometric and structurally controlled manner; such assembly is necessary to minimize heterogeneity within the bioconjugate and provide intimate control over the experimental form.
Thermodynamic Properties of Water + Ethylene Glycol at 283.15, 293.15, 303.15, and 313.15 K

Excess volumes (VE), viscosity deviation (Δη), excess refraction (ΔR), and surface excess (σE) of water + ethylene glycol have been determined over the entire composition range at a number of temperatures. The results are fitted to a Redlich−Kister equation, and the corresponding parameters are derived. All the properties have negative values and exhibit a minimum at the same water-rich region of the solution. The results are discussed in terms of molecular interactions.
DNA on fluid membranes : A model polymer in two dimensions

The polymeric properties of DNA molecules, which are electrostatically bound to glass-supported cationic lipid membranes, are investigated. The electrostatic interaction is sufficiently strong to hold DNA flat onto the fluid lipid surface but allows DNA to diffuse freely in-plane. The molecules are fluorescently labeled, and fluorescence images are examined in terms of real-space monomer distributions of polymer chains. The chain extension of single DNA fragments of restriction enzyme digests shows power law scaling with number of base pairs in accordance with self-avoiding walks in two dimensions. Dynamic scaling is found for center-of-mass diffusion following Rouse dynamics, D ∼ 1/N, and for rotational relaxation times, τr ∝ Nμ with μ = 2.6 ± 0.4. A crowded surface of monodisperse λ-DNA behaves like a two-dimensional semidilute solution with a measurable correlation length ξ being smaller than for dilute preparations. Polymer unbinding and the role of surface defects are discussed.
Numerical investigation of thermal disassociation of ZnO for hydrogen production: Parametric study and reactor configuration

The present research is focused on the two‐step ZnO/Zn thermochemical water splitting cycle for hydrogen production. In the present paper, the numerical modeling of the first step, which involves endothermic reduction of zinc oxide (ZnO), is carried out in a cylindrical reactor using Computational Fluid Dynamics (CFD). The parametric study shows that the fractional conversion of ZnO increases with an increase in the flow rate of ZnO, while it decreases with an increase in the ZnO particle diameter and carrier gas mass flow rate. Six different reactor configurations are also assessed comprehensively. It is observed that a cylindrical reactor with a tangential inlet at the top plane and a tangential outlet at the bottom plane has higher robustness to the variation of various operating parameters with consistently high ZnO fractional conversion. Copyright © 2013 John Wiley & Sons, Ltd.
Vacuum‐Ultraviolet Photolysis of Ethane Films

The vacuum‐ultraviolet photolysis of films of solid ethane has been studied both at 1470 and 1236 A. The product distributions have been measured and evidence is presented for the quenching of excited ethane and ethylene. The over‐all mechanism, with the exception of quenching reactions, appears to be the same as in the gas‐phase photolysis.
Structures, and Reactivities with Formaldehyde, of Some Acetosolv Pine Lignins

Abstract Lignins obtained from pine by the acetosolv process under various operating conditions were characterized structurally by elemental and methoxyl analyses, and FTIR. and NMR spectroscopy, and their reactivity with formaldehyde was determined. The reactivity results, including NMR quantification of the introduced methylol groups, suggest that the methylolated lignins are suitable for the formulation of adhesives.
Modified Carrageenan. 1. H-CarragPAM, a Novel Biopolymer-Based Superabsorbent Hydrogel

A novel kappa-carrageenan (C)-based superabsorbing hydrogel was synthesized through graft copolymerization of acrylamide (AAm) onto a C substrate in the presence of a crosslinking agent. The crosslinked C-poly(AAm) polymer graft was partially hydrolyzed in alkaline medium to yield a superabsorbent resin, H-carragPAM. The resin structure was confirmed using FTIR spectroscopy. The variables of graft copolymerization (monomer, initiator, polysaccharide and crosslinker concentration, reaction temperature and time as well as stirrer speed) that affected on the ultimate water-swelling capacity were optimized. The time-temperature variation of the copolymerization was investigated in terms of the absence and presence of the atmospheric oxygen. Under optimized conditions, the maximum capacity of swelling in distilled water and saline (0.9wt% NaCl) were 1,465 and 121g/g, respectively. Since this hydrogel exhibited a very high absorptivity in saline, it may be referred to as low salt sensitive superabsorbent.