Miracle-dz/UniFAR-FTUs huggingface dataset:
Reactive surfactants in heterophase polymerization. XVI. Emulsion copolymerization of styrene-butyl acrylate-acrylic acid in the presence of simple maleate reactive surfactants

This study deals with the influence of a copolymerizable surfactant on the stability of lattices. Two main reactive surfactants, one anionic and one nonionic, both containing a reactive part issued from maleic anhydride, were engaged in seeded emulsion polymerizations of styrene-co-butyl acrylate-co-acrylic acid. The importance of the polymerization conditions clearly appears through the incorporation yield of the surfmers: When good conditions are used, this yield can be as high as 80%. Once stable lattices are synthesized, with a great incorporation of the surfactant, the stability of the colloid (against freeze–thawing cycles or in the presence of concentrated divalent electrolyte solutions) is then largely improved. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2768–2776, 2000
The coalescence and bouncing of water drops at an air/water interface

A detailed study has been made of the conditions under which uncharged water drops of radius 60 to 200 μm coalesce or rebound at a clean water/air interface. The variable para-meters in the system are the drop radius, r, its impact velocity, Vi, and the angle of impact, θi; and the dependent parameters are the time of contact, T, between a rebounding drop and the water surface, the velocity, Vb, and the angle θb with which it leaves the surface. All these have been measured. Relations are established between the drop radius and the critical values of Vi and θi at which coalescence occurs between uncharged drops and plane or convex water surfaces. Drops impacting at nearly normal incidence remain in contact with the surface for about 1 ms, lose about 95 % of their kinetic energy during impact, and rebound with an effective coefficient of restitution of about 0.2. Drops carrying a net charge and drops polarized in an applied electric field coalesce more readily than uncharged drops of the same size and impact velocity. The magnitudes of the critical charges and critical fields required to cause coalescence are determined as functions of Vi, θi and drop radius. Typically, drops of radius 150 μm impacting at 100 cm/s coalesce if the charge exceeds about 10-4 e. s. u. or if the field exceeds about 100 V/cm. If the motion of a drop rebounding from a plane water surface is treated as simple harmonic and undamped, one may derive expressions for the depth of the crater, x and the restoring force, F, at any stage, and also for the time of contact. These yield values that are in reasonable accord with experiment. However, the collision is clearly inelastic, and a second solution is obtained when F is assumed to be proportional, not only to the displacement, x, but to x/t. This leads to a slightly different expression for the time of contact and to a calculated energy loss of 84 % compared with the measured value of 95 %. If the drop is to coalesce with the water surface, it must first expel and rupture the intervening air film. Treating the undersurface of the drop as a flattened circular disk, an expression is determined for the minimum thickness, δ, achieved by the film during the period of contact, in terms of Vi, θi and the drop radius r. This predicts values of δ ~ 0.1 μm below which fusion may well take place under the influence of van der Waals forces. Several features of the observed relations between Vi, θi and r are accounted for by this simplified theory, but the behaviour of drops impacting at nearly glancing incidence, and of relatively large, energetic drops impacting nearly normally is not. In the latter case, the observed distortion of the drop is thought to play an important role in permitting more rapid thinning of the air film and, in the case of charged and polarized drops, by producing intense local electric fields that may cause the final rupture.
Acetylene‐Enhanced Growth of Carbon Nanotubes on Ceramic Microparticles for Multi‐Scale Hybrid Structures

A mixture of acetylene and xylene is used as the carbon source to directly synthesize carbon nanotube (CNT)/alumina (Al2O3) microsphere hybrid structures by CVD. The hybrid structures are modulated by varying the acetylene ratio and reactor temperature. The addition of acetylene can significantly improve the CNT growth rate on Al2O3 at temperatures lower than 600 °C. A tenfold improvement in CNT growth rate is obtained at 550 °C when only 2 vol.-% acetylene is added. Meanwhile, acetylene favors the formation of bundles containing high-density CNTs. The increase in the temperature promotes the formation of CNTs with large diameters and low number density. Mass spectrometry (MS) is used to investigate the decomposition of a mixture of acetylene/xylene at temperatures ranging from 450 to 700 °C, under the experimental conditions used. Acetylene decomposes with an increasing rate with temperature from 450 °C, however notable decomposition of xylene is not detected below 700 °C, which corresponds to the formation of the CNTs of varied diameters. This study demonstrates the possibility of large-scale production of desired nano/micrometer multifunctional CNT/Al2O3 hybrid fillers using a gas/liquid mixed carbon source.
Preparation, structure and photocatalytic properties of cancrinite encapsulating lead and sulfide ions

Cancrinites encapsulating Pb2+ and S2− ions have been prepared by hydrothermal and cation-exchange processes, and their structures and photocatalytic properties have been investigated. The structure analyses revealed that Pb2+ ions exchanged with Na+ ions were statistically located around S2− ions in the same micropore, and the mean Pb–S bond lengths were estimated to be about 3.0 A. It was found that the resulting specimens had photocatalytic properties, corresponding to an absorption band based on an electron transition between Pb2+ and S2− ions, from the decolorization of methylene blue aqueous solution under black light irradiation. Treating the specimens at 400 °C under an N2 atmosphere enhanced the photocatalytic property.
Development of Branching in Atom Transfer Radical Copolymerization of Styrene with Triethylene Glycol Dimethacrylate

The branching copolymerization of styrene with triethylene glycol dimethacrylate (tri-EGDMA) as the branching agent was carried out using atom transfer radical polymerization (ATRP) in anisole at 90 °C. The resulting copolymers were analyzed using 1H NMR and triple detection size exclusion chromatography (TD-SEC). The NMR analysis shows that the pendent vinyl groups react even in the early stages of the polymerization. Analysis of the changes in the molecular weight and polydispersity of the copolymers suggests that the reaction system contains three components: the primary chains, the slightly branched chains comprising of two primary chains, and the highly branched chains consisting of more than three primary chains. The coupling reaction mainly takes place between the primary chains, resulting in the slightly branched chains in the early stages of the reaction, the weight fraction of the branched chains and the degree of branching increase gradually with monomer conversion, highly branched chains mainl.
Properties of a new soft magnetic material for AC and DC motor applications

A new soft magnetic material has been developed for ac and dc motor applications. The motor components are made by a powder metallurgical process in contrast to the traditional method of stacking punched laminations. This new material offers many manufacturing advantages. Also, because of its low eddy current loss, it has good high frequency magnetic properties, 88 W/kg core loss when measured at 400 Hz and at an induction of 1.5 T. Components manufactured from this new magnetic material have demonstrated comparable performance at 60 Hz and superior performance for frequencies > 60 Hz when compared to cold rolled motor lamination steels. The variation of magnetic properties of the material when it is processed under different conditions, such as pressed at various pressures, shall be discussed. The new pressed material also has outstanding dc properties when sintered.
Survival in Sterile Soil and Atrazine Degradation of Pseudomonas sp. Strain ADP Immobilized on Zeolite

ABSTRACT In laboratory settings, the ability of bacteria and fungi to degrade many environmental contaminants is well proven. However, the potential of microbial inoculants in soil remediation has not often been realized because catabolically competent strains rarely survive and proliferate in soil, and even if they do, they usually fail to express their desired catabolic potential. One method to address the survival problem is formulating the microorganisms with physical and chemical support systems. This study investigates the survival of Pseudomonas sp. strain ADP in sterile soil and its retention of atrazine-degrading functionality. Assessment was conducted with free and zeolite-immobilized bacteria incorporated into the soil. Pseudomonas sp. strain ADP remained viable for at least 10 weeks when stored at 15°C in sterile soil. Cell numbers increased for both free and zeolite-immobilized bacteria during this period, except for free cells when grown in Miller's Luria-Bertani medium, which exhibited constant cell numbers over the 10 weeks. Only the zeolite-immobilized cell retained full functionality to degrade atrazine after 10 weeks in sterile soil regardless of the medium used to culture Pseudomonas sp. strain ADP. Functionality was diminished in free-cell inoculations except when using an improved culture medium. Survival of zeolite-immobilized Pseudomonas sp. strain ADP separated from the soil matrix after 10 weeks’ incubation was significantly (p < .05) greater than in soil inoculated with free cells or in the soil fraction inoculated by release from zeolite-immobilized Pseudomonas sp. strain ADP.
Effects of root temperature and nitrogen form on magnesium uptake and translocation by wheat seedlings

Abstract Low concentrations and low bioavailability of Mg in winter wheat forage have been related to grass tetany, a metabolic disorder of grazing ruminants caused by Mg deficiency in the blood serum. To investigate the effects of root temperature, N form, and Mg supply on Mg uptake and translocation by winter wheat (Triticum aestivum L. ‘Centurk'), seedlings were grown in nutrient solution with three root‐zone temperatures (RZT) (10, 15, or 20 °C), three N forms (NH4:NO3 in mM 10:0, 5:5, or 0:10), and two Mg levels (0.4 or 4 mM). Increasing the RZT increased Mg uptake rates of seedlings less than 30 days old, but decreased Mg uptake rates for plants more than 30 days old. Magnesium uptake rates were significantly higher for plants supplied only NO3 than for plants supplied only NH4. However, increasing the proportion of NO3 significantly decreased net Mg translocation. Consequently, shoot Mg concentrations at the low Mg level were significantly decreased by increasing the proportion of NO3. As was found.
Swelling Characterization and Adsorptive Features of Acrylamide/Itaconic Acid Hydrogels and Semi-IPNs for Uranyl Ions

A novel semi-interpenetrating network (semi-IPNs) hydrogel, composed of acrylamide (AAm) with itaconic acid (ITA) as co-monomer, with poly (ethylene glycol)(PEG) and trimethylolpropane triacrylate (TMPTA) was prepared. Hydrogels and semi-IPNs were synthesized by free radical solution polymerization. Swelling experiments were performed in water and aqueous solutions of uranyl acetate. Diffusion behavior was investigated and their diffusion into hydrogels was found to be non-Fickian in character. Sorption of uranyl ion onto the polymeric system was studied by a batch sorption technique at 25°C. The sorption capacity, removal effiency and partition coefficient of the hydrogels were investigated.
Microcrystalline chitosan : some areas of application

Microcrystalline chitosan existing as a new microcrystalline form of standard poly(2-deoxy-2-amino-D-glucose) is a special functional polymeric material suitable for several applications. New areas of microcrystalline chitosan use in the textile industry, waste water treatment and medicine are presented. Microcrystalline chitosan in the applications discussed has practical and economic advantages over standard chitosan.
Structure and dynamics of the water/MgO interface

A pairwise additive potential energy expression for the water/MgO interaction was obtained by fitting the parameters to ab initio electronic structure energy data, computed using correlation-corrected periodic Hartree−Fock (PHF) theory, at selected adsorbate/surface geometries. This potential energy expression was used in molecular dynamics and Monte Carlo simulations to elucidate the water/MgO interaction. Energy minimization reveals a nearly planar adsorbate/surface equilibrium geometry (−15° from the surface plane with the hydrogens pointing toward the surface oxygens) for an isolated water on perfect MgO (001), with a binding energy of 17.5 kcal/mol; subsequent PHF calculations on this system confirmed that this is a potential minimum. Rate constants for desorption (kdsorb), intersite hopping (khop), intrasite rotation (krot), and intrasite flipping (kflip) were estimated for an isolated water on the surface using simple transition state theory. The computed rates (at T = 300 K) are kdsorb = 1.1 × 105.
The relationship between children's spontaneous focusing on number and math skills

Spontaneous focusing on numerosity (SFON) measures children’s tendency to focus on numerical information without being prompted and has been linked to later math abilities. Past work has utilized various methods of quantifying children’s SFON yet has not directly compared non-verbal and verbal behaviors. In this study, we investigated the individual differences in the speech and actions of children performing SFON tasks and examined how each measure of children’s SFON tendencies were related to their math skills. 115 four-year-old children completed four imitation and modeling SFON tasks over two separate visits to the lab. Children also completed a math assessment two months later as a measure of their math abilities. Within each of the four tasks, no correlations were observed between children’s speech and actions. However, children who focused on number in one modality during one task tended to focus on number in that same modality for other tasks. Further, children’s focusing on number was predictive of their future math abilities, but specifically through action and not speech.
On the Source of the Submicrometer Droplet Mode of Urban and Regional Aerosols

While atmospheric aerosols are typically described as consisting of three modes, the nucleation mode (0.01–0.1 μm in diameter), the accumulation mode (0.1–1.0 μm in diameter), and the coarse mode (> 1 μm in diameter), ambient measurements have shown that two distinct modes can exist in the 0.1–1.0-μm diameter range. These modes are referred to as the condensation mode (approximate aerodynamic diameter of 0.2 μm) and the droplet mode (approximate aerodynamic diameter of 0.7 μm). It has been postulated that the droplet mode results from aqueous-phase chemistry (Hering and Friedlander, 1982; John et al., 1990). In this work we examine the mechanisms of formation of the droplet mode. It is shown that growth of condensation mode particles by accretion of water vapor or by gas-phase or aerosol-phase sulfate production cannot explain the existence of the droplet mode. Activation of condensation mode particles to form fog or cloud drops followed by aqueous-phase chemistry and fog evaporation is shown to be a plau.
Epitaxial growth a-plane ZnO films on a-GaN/r-Al2O3 templates

In this work, we have grown a-plane ZnO films on a-plane GaN/r-sapphire templates by pulsed laser deposition. The aplane GaN of the templates is aimed to mitigate the large lattice mismatch between ZnO and sapphire, and was grown by metal organic chemical vapor deposition. The grown a-plane ZnO films have been analyzed by various techniques such as high resolution X-ray diffraction, photoluminescence. It shows that high quality a-plane ZnO films have been achieved by our growth method.
Disulfide-Stabilized Poly(methacrylic acid) Capsules: Formation, Cross-Linking, and Degradation Behavior

We report the preparation of monodisperse, single-component degradable polymer capsules for potential applications in encapsulation, catalysis, and controlled drug delivery. The synthesized capsules, composed entirely of poly(methacrylic acid) (PMA), are obtained by the sequential deposition of thiolated poly(methacrylic acid) (PMASH) and poly(vinylpyrrolidone) (PVPON) onto silica particles, controlled oxidation of thiol groups into bridging disulfide linkages in the PMASH, removal of the silica particles, and finally, release of PVPON by altering the solution pH to disrupt hydrogen bonding between PMASH and PVPON. The PMA capsules are held together solely through biodegradable disulfide linkages. We demonstrate that the capsules undergo reversible swelling in response to changes in external pH, and degrade in the presence of a physiological concentration of a natural thiol-containing peptide, glutathione. These capsules are of interest for in vivo applications, where degradation of the capsules, through .
Synthesis, Characterization, and Properties Evaluation of Methylcoumarin End-Functionalized Poly(methyl methacrylate) for Photoinduced Drug Release

The synthesis of novel methylcoumarin end-functionalized poly(methyl methacrylate) of different molecular weights using atom transfer radical polymerization (ATRP) is reported. 7-(2′-Bromoisobutyryloxy)-4-methylcoumarin was used as the ATRP initiator at 70 °C using copper(I) bromide/1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The theoretical and experimental number-average molecular weights Mn with narrow polydispersities (Mw/Mn = 1.1−1.4) agreed very well. Photochemical drug loading of the methylcoumarin end-functionalized polymer was performed in solution (chloroform/acetone 1:2) with benzophenone as additional photosensitizer using a 50-fold excess of the pro-drug 1-heptanoyl-5-fluorouracil (H5FU). UV/vis and NMR spectroscopy were used for the characterization of the polymer drug conjugate and indicated an almost quantitative conversion of coumarin moieties into photodimers. The change of polymer properties like thermal stability, glass transition, and molecular weight afte.
Biodegradation of BTEX Compounds by a Mixed Culture Obtained from Petroleum Formation Water

The biodegradation of BTEX compounds (benzene, toluene, ethyl benzene, and o,m,p-xylenes) by a mixed culture obtained from the formation of water, produced from the petroleum wells of the Turkish Petroleum Corporation (TPAO) in the Adıyaman region (southeast Turkey), and the effect of biomass concentration on the biodegradation rate of BTEX compounds, both alone and as a mixture, were investigated. The mixed culture, identified as Pseudomanas stutzeri and Vibrio mimicus, was grown on a brain heart infusion enriched medium at 30°C before its use in the biodegradation experiments. The biodegradation experiments were carried out using nonadapted, benzene-adapted, and toluene-adapted microorganisms. It was found that the mixed culture obtained degraded all BTEX compounds, both alone and as a mixture, and the overall specific biodegradation rates of BTEX compounds individually were higher with toluene-adapted microorganisms (both benzene and toluene: 4.27 mg/g biomass-day) than with the nonadapted (benzene: 0.096; toluene: 1.355 mg/g biomass-day) and benzene-adapted microorganisms (benzene: 3.4; toluene: 1.6 mg/g biomass-day). Similar results were obtained for BTEX compounds in a mixture. When the initial biomass concentration increased from 0.42 g/L to 2.34 g/L, the time required for complete biodegradation of both benzene and toluene decreased from 3 to 2 days with toluene-adapted microorganisms.
Spectroscopic Study of Tempo-Oxidized Deinked Pulp

Abstract Deinked pulps are not currently used in value-added paper manufacturing. To implement their use, both strength and optical properties must be improved. TEMPO oxidation has been shown to improve strength properties of thermomechanical and deinked pulps. However, a significant reduction of the pulp brightness results due to yellowing of mechanical fibers. Spectroscopic techniques were used to investigate the effect of TEMPO oxidation on deinked fiber properties. Fourier transform infra-red (FTIR) spectroscopy and UV/VIS spectrum showed that oxidation conditions are driving important chemical reactions that affect optical properties. Results indicated that ortho-quinone compounds as well as carboxylic groups are generated depending on oxidation conditions resulting in pulp brightness decrease. Spectroscopic studies also revealed that residual ink detachment from fiber surfaces is occurring during oxidation contributing to improve pulp brightness.
Trace metals in lipsticks

Cosmetics still retain their glittering appeal, but public concern about their toxicity has become a hot issue. Trace amounts of toxic metals can be either intentionally added to cosmetics or present as impurities in the raw materials. We therefore assessed the levels of lead, cadmium, nickel, chromium, mercury, antimony, and arsenic in 14 brands of lipstick (28 samples) that are widely available in local Saudi markets. This study found that the levels of all metals were generally lower than the specifications of the US Food and Drug Administration for metallic impurities in color additives used in cosmetics. Only one brand of lipstick exceeded the specifications, containing levels of arsenic higher than 3 ppm. Also, the levels of nickel and chromium contents in 10 and 4 of the 28 lipsticks, respectively, were above 1 ppm, the trigger limit of allergic contact dermatitis (ACD). Despite the metallic contents in lipsticks being below the acceptable limits for impurities in color additives used in the cosmetic industry, safer limits should be seriously considered, especially for those causing ACD.
Structure-property relationships in biomedical thermoplastic polyurethane nanocomposites

Polyurethanes are excellent potential materials for the construction of implantable medical components due to their exceptional mechanical properties and biocompatibility. Currently, soft silicone materials are employed as insulation for implantable cochlear electrode arrays. Siloxane-based thermoplastic polyurethane (TPU) nanocomposites containing synthetic layered silicates are being investigated as new insulation materials with superior tensile and tear strength and reduced surface tack, potentially allowing for thinner insulation and more intricate electrode designs. In this work, ElastEon E5-325 (Aortech Pty Ltd.) TPU nanocomposites reinforced with 2 and 4 wt % low aspect ratio organo-hectorite and high aspect ratio organo-fluoromica (Lucentite SWN, Somasif ME100, both modified with octadecyltrimethylammonium (ODTMA)) were prepared by a solvent casting technique. The mechanical properties of the resulting nanocomposites were measured by tensile, tear, stress relaxation, and creep testing and morphologically were characterized by DSC, DMTA, XRD, TEM, and strained in situ synchrotron SAXS. We found that the hydrophobic low aspect ratio organohectorite acts as a very potent interfacial compatibilizer. At 2 wt % loading, the resulting nanocomposite displays vastly superior mechanical properties to both soft silicone and ElastEon. In addition to providing 30 nm × 1 nm synthetic nanosilicate reinforcing elements which are readily capable of orientation and reinforcement, these nanosilicates also serve to provide more cohesive hard microdomains and thus creep resistance and dimensional stability. Interestingly, at a higher (4 wt %) loading of organohectorite, gross morphological changes in the TPU microdomain texture are observed, adversely effecting the mechanical properties of the TPU.