Sprayable Castables,the Effect of Smaple Preparation on Properties

Two alumina based castables,low and ultralow-ce-ment,and one castable based on a basic bond system of MgO and microsilica were spray gunned using a proprietary accellerator and commercially available equipment.Besides being sprayed,also shoe-box sized samples were cast prior to the spraying .Together with samples cast in the laborato-ry,these three samples and compositions were tested asnd compared.     

Effects of Zn, Cu, and K Promoters on the Structure and on the Reduction, Carburization, and Catalytic Behavior of Iron-Based Fischer–Tropsch Synthesis Catalysts

Zn, K, and Cu effects on the structure and surface area and on the reduction, carburization, and catalytic behavior of Fe–Zn and Fe oxides used as precursors to Fischer–Tropsch synthesis (FTS) catalysts, were examined using X-ray diffraction, kinetic studies of their reactions with H₂ or CO, and FTS reaction rate measurements. Fe₂O₃ precursors initially reduce to Fe₃O₄ and then to metallic Fe (in H₂) or to a mixture of Fe_2.5C and Fe₃C (in CO). Zn, present as ZnFe₂O₄, increases the surface area of precipitated oxide precursors by inhibiting sintering during thermal treatment and during activation in H₂/CO reactant mixtures, leading to higher FTS rates than on ZnO-free precursors. ZnFe₂O₄ species do not reduce to active FTS structures, but lead instead to the loss of active components; as a result, maximum FTS rates are achieved at intermediate Zn/Fe atomic ratios. Cu increases the rate of Fe₂O₃ reduction to Fe₃O₄ by providing H₂ dissociation sites. Potassium increases CO activation rates and increases the rate of carburization of Fe₃O₄. In this manner, Cu and K promote the nucleation of oxygen-deficient FeO _x species involved as intermediate inorganic structures in reduction and carburization of Fe₂O₃ and decrease the ultimate size of the Fe oxide and carbide structures formed during activation in synthesis gas. As a result, Cu and K increase FTS rates on catalysts formed from Fe–Zn oxide precursors. Cu increases CH₄ and the paraffin content in FTS products, but the additional presence of K inhibits these effects. Potassium titrates residual acid and hydrogenation sites and increases the olefin content and molecular weight of FTS products. K increases the rate of secondary water–gas shift reactions, while Cu increases the relative rate of oxygen removal as CO₂ instead of water after CO is dissociated in FTS elementary steps. Through these two different mechanisms, K and Cu both increase CO₂ selectivities during FTS reactions on catalysts based on Fe–Zn oxide precursors.     

Effect of α-, β-, γ-, and δ-Tocotrienol on the Oxidative Stability of Lard

Despite the structural similarity of tocopherols, the antioxidative activities of tocotrienol homologues have not been studied often. In this study, the antioxidant activities of α-, β-, γ-, and δ-tocotrienols at various concentrations from 100 to 1,000 ppm in lard were evaluated. Headspace oxygen content of the lard without tocotrienol decreased from 21.1 to 10.7 % and the peroxide value increased from 0.4 to 33.4 mequiv/kg after 7 days of storage at 55 °C in the dark. α-Tocotrienol at 100 ppm and β-tocotrienol at 100 and 200 ppm effectively improved the oxidative stability of lard; however, the antioxidative activities of α- and β-tocotrienol reduced as the concentration increased to 1,000 ppm. The γ- and δ-tocotrienols improved the oxidation stability of lard and the effectiveness was essentially same at all concentrations (p > 0.05). The antioxidative activities of tocotrienols in the autoxidation of lard increased in the order of α-, β-, γ-, and δ-tocotrienols. The activities of tocotrienols in lard were different depending on the type of homologues and concentrations.     

Influence of pH on the preparation of monometallic rhodium and platinum,and bimetallic RhodiumPlatinum Catalysts supported on γ-Alumina

¹⁹⁵PtNMR and Raman experiments indicated that H₂PtCl₆ adsorbed monomolecularly on the surface of alumina up to a loading of 1 μmol m⁻² during pore volume impregnation. Above this limit crystalline H₂PtCl₆ was formed during the subsequent drying procedure. Adsorption experiments showed that RhCl₃ exhibited the same behaviour, with an even larger monomolecular coverage. The coverage of both metal complexes was dependent on the pH during adsorption and decreased with decreasing pH, due to a shift in the bonding equilibrium between the metal complexes in solution and the complexes adsorbed on the support surface. Because of the acidic properties of RhCl₃ and H₂PtCl₆, the amounts of rhodium and platinum adsorbed during co-adsorption were smaller than during adsorption of the separate metal complexes. The reduction of RhCl₃+H₂PtCl₆ supported on Al₂O₃ was governed by mobile rhodium atoms and small bimetallic clusters. Large metal salt crystals smothered the reduction process.     

Synthesis,characterization, and performance comparison of boron using adsorbents based on N-methyl-D-glucosamine

Using N-methyl-D-glucosamine(NMDG) as the functional monomer, glycidyl methacrylate(GMA) as the connecting monomer, functionalized Fe₃O₄ nano-particles(NPs) as the support, three adsorbents were prepared including direct polymer GMA-NMDG, magnetic GMA-NMDG polymer(MGN), and boron magnetic ion-imprinted polymer(BMIIP). Based upon the optimization of synthesis conditions, the prepared adsorbents and intermediate products were characterized using Fourier transform infrared spe...     

Effect of α-, β-, γ-, and δ-Tocotrienol on the Singlet Oxygen Oxidation of Lard

The impacts of four different types of tocotrienol homologues on the singlet oxygen oxidation of lard were evaluated by measuring the headspace oxygen content and the peroxide value. Singlet oxygen oxidation of lard was induced by chlorophyll photosensitization. Samples of 0.100, 0.250, and 0.400 M lard in methylene chloride containing chlorophyll and α‐, β‐, γ‐, or δ‐tocotrienol were prepared and stored under light at 3,000 lux for 4 h. All tocotrienol homologues at 1.20 mM significantly prevented the singlet oxygen oxidation of lard. Chlorophyll under light produced singlet oxygen at 1.09 μmol oxygen/mL headspace/h. A steady state kinetic study showed that tocotrienols reduced the singlet oxygen oxidation of lard by quenching the singlet oxygen. Singlet oxygen reacted with lard at 6.50 × 10⁴M^?1 s^?1. α‐, β‐, γ‐, and δ‐tocotrienol quenched singlet oxygen with the rate of 2.16, 1.99, 2.05, and 0.800 × 10⁷M^?1 s^?1, respectively. Among them, α‐tocotrienol significantly prevented singlet oxygen oxidation of lard.     

Influence of novel carrier Soluplus® on aqueous stability,oral bioavailability,and anticancer activity of Morin hydrate

Present work demonstrated the influence of novel amphiphilic carrier Soluplus^® on the solubility and oral bioavailability of Morin hydrate (MOR). Spray-dried solid dispersions (SSD) were developed using the design of experiment (DoE). Saturation solubility study of the optimized formulation SSD F(7) showed many fold increment in the solubility with acceptable aqueous stability. In vitro drug diffusion kinetics suggested Weibull model to be the best fit. In vitro cytotoxicity assay revealed a significant increase in the anticancer potential compared to innate MOR. Furthermore, SSD F(7) showed 2.27-fold enhancement in the relative bioavailability as compared to MOR.     

Effect of Surfactants and Temperature on Adsorption Behavior of Metal Ions on Organic–Inorganic Hybrid Exchanger,Acrylamide Aluminum Tungstate

The adsorption behavior of a thermally and chemically stable hybrid ion-exchange material, acrylamide aluminum tungstate was explored in cationic (CTAB) and anionic (SDS) surfactants and acidic solvents. Critical micellar concentration (CMC) appears to be an important parameter in determining the adsorption behavior of metal ions. Equilibration time and temperature studies on the distribution coefficient of metal ions were studied. On the basis of the distribution coefficient, this material was successfully used for quantitative separations of some binary synthetic mixtures of metal ions by the column method. Hg(II) ion was selectively determined quantitatively in synthetic mixture. The material appears to be promising for separating toxic metal ions in a real matrix (industrial effluents and waste water) and can be utilized as a packing material in HPLC and GC columns for faster and more efficient separation.

Effect of Ti （C,N） on Properties of Low-carbon MgO- C Bricks

The effect of Ti （ C, N） on properties of low-carbon MgO - C bricks was investigated. The phase composition and the microstructure of the matrix of low-carbon MgO - C brick containing Ti （ C, N） were studied by XRD and SEM analysis together with EDS. The results showed that Ti （ C, N） distributed in the matrix of lowcarbon MgO - C brick uniformly after being treated at 1 600 ~C for 3 h in coke powder bed, and Ti （C, N） and MgO formed a solid solution. After the treatment at 1 600 ℃ for 3 h in coke powder bed, the bulk density and cold crushing strength of low-carbon MgO - C brick with Ti （ C, N） decreased, and the apparent porosity and linear change rate of specimens increased. The oxidation resistance of low-carbon MgO - C brick with Ti（ C, N） was superior to that of low-carbon MgO - C brick with no additives, but inferior to that of low-car- bon MgO - C brick with Al powder. The slag resistance of the specimen with Ti （ C, N） was excellent as well.     

Effect of Head Groups,Temperature, and Polymer Concentration on Surfactant—Polymer Interactions

The micellization behaviour of sodium dodecyl sulphate, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and cetylpyridinium chloride in water and in aqueous solutions of polyethylene oxide (PEO, molecular weight = 100,000) having concentrations (0.005–0.04 %, w/v) has been studied at different temperatures (288.15–318.15 K) using conductivity, surface tension, and viscosity methods. From conductivity measurements various micellar parameters, like critical micellar concentration (CMC), critical aggregation concentration (CAC), polymer saturation point (PSP), degree of ionization (β), and standard free energy of transfer ( \( \Delta G_{t}^{0} \) ), have been calculated. CAC values have been found to decrease with polymer concentration and increase with temperature. However, the PSP values increase with both polymer concentration and temperature for all surfactants. Similar parameters have also been calculated from surface tension data (CMC^σ, CAC^σ, PSP^σ) along with other parameters such as maximum surface excess concentration at the air/water interface ( \( \Gamma_{\hbox{max} } \) ), minimum area per molecule (A _min), and packing parameter (p). The CMC^σ, CAC^σ, and PSP^σ values are smaller than the corresponding CMC, CAC, and PSP values, but both show similar behaviour with temperature and concentration of polymer. Various parameters indicate that the presence of the aromatic ring in the head group of surfactant decreases its interaction with PEO, whereas the increased hydrophobicity in the tail leads to stronger interactions with PEO. Viscosity studies further supplement the conclusions drawn from the above results.     

Influence of source,rate, and method of applicating controlled release fertilizer on nutrient release and growth of ‘Savannah’ holly

An experiment was conducted to determine the effect of rate of fertilizer application and method of application on the rate of nutrient release and growth of Savannah holly (Ilex ×attenuata Ashe) using three controlled release fertilizers. The controlled release fertilizers used were Osmocote 17N—3P—9.9K, Sierrablen 17N—3P—8.3K, and High-N 24N—1.7P—5.8K, all 12 to 14 month formulations. The three fertilizers had different release rates as determined by leachate nitrate—N and electrical conductivity (EC) measurements. Topdressing of fertilizer had the greatest release rate at seven days after treatment compared to fertilizer incorporation which had the lowest EC readings at 120 days after treatment. Fertilizer source had no effect on the shoot growth of Savannah holly. Growth index and shoot dry weight of Savannah holly increased linearly as N rate increased from 0.9 to 2.1 kg N m^–3. A significant linear relationship (R² = 0.97, Nitrate—N = 409 (EC)) between nitrate—N and EC indicates that nitrate—N concentration can be estimated from EC readings when the pour-through method is used with multicoated controlled release fertilizers. The controlled release fertilizers used in this study provided adequate nutrient release rates for up to four months under outdoor nursery conditions during the months of June through October.     

Supercritical antisolvent processing of γ-Indomethacin: Effects of solvent, concentration, pressure and temperature on SAS processed Indomethacin

γ-Indomethacin (IMC) is successfully processed with the supercritical antisolvent (SAS) technique. Pure, acicular (needle-like) particles of the α-polymorph are consistently obtained with SAS as the solvent, concentration, temperature and pressures are varied. Controlled changes in process parameters yield significant changes in particle size. Enhanced dissolution profiles are observed with IMC processed with SAS as opposed to the unprocessed IMC. The reduced particle size, as well as the α-polymorphic form of IMC, contributes to the enhanced dissolution rate.     

Composition,Microstructure and Application of Bauxite Based on Miner al Seperation

In this paper,Yangquan bauxite based on mineral seperation are investigated.It is found that the glass phase will be decreased and the high temperature mechanical propertieds will be improved.     

Study on the effect of Ti,Al, Cu,and Ag doping on the bonding properties of soldered β-Sn(100)/ZrO2(111) interface

Selecting active elements for filler metal is very important in soldering of ZrO₂ ceramics. In this paper, the effects of Ti, Al, Cu, and Ag active elements on the bonding strength and electronic structures of soldered β-Sn(100)/ZrO₂(111) interface were studied via the method of first principle calculation. The work of adhesion (W_ad) results show that the O₂-terminated interface is more stable than other kinds of interfaces. Then, the atoms of Ti, Al, Cu, and Ag were doped into the interface by replacing the Sn atom in situ. It is found that additions of Ti, Al, and Cu atoms can increase the W_ad, and Ag atom has the opposite effect. From the results of heat of segregation, doping Ti and Al into the interface is stable in thermodynamics and doping Cu and Ag is not stable. The forming of strong ionic-covalent Ti-O and Al-O bonding contributes to the increase of the interfacial adhesion strength. The calculation results indicate that Ti and Al can act as active elements in Sn to solder ZrO₂. The Ti-O and Al-O compounds formed at interface can improve the wetting and bonding between Sn-based solder and ZrO₂ ceramics.     

Effect of cerium concentration on microstructure,morphology and corrosion resistance of cerium–silica hybrid coatings on magnesium alloy AZ91D

The aim of this work was to investigate the effect of cerium concentration on microstructure, morphology and anticorrosion performance of cerium–silica hybrid coatings on magnesium alloy AZ91D. Vinyltriethoxysilane (VETO) and γ-glycidoxypropyltrimethoxysilane (GPTMS) were employed as precursors to prepare sol–gel based silica coating. Cerium nitrate hexahydrate as dopant in five different concentrations was added into the silica coatings. Fourier transform infrared (FT-IR) spectrum analysis, viscosity measurements and scanning electron microscopy (SEM) were employed to characterize the microstructure and morphology of these coatings. It was found that with the increase of cerium concentration, the degree of decomposition of silane chains in the coating network increased. The corrosion resistance of the cerium–silica hybrid coatings was estimated by electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests. The results demonstrated that corrosion resistance of coatings initially increases and then decreases as cerium concentration goes up. When the cerium concentration is 0.01 M, corrosion resistance reaches its maximum.     

Influence of α-Si3N4 coarse powder on densification,microstructure, mechanical properties,and thermal behavior of silicon nitride ceramics

Silicon nitride (Si₃N₄) ceramics, with different ratios of fine and coarse α-Si₃N₄ powders, were prepared by spark plasma sintering (SPS) and heat treatment. Further, the influence of coarse α-Si₃N₄ powder on densification, microstructure, mechanical properties, and thermal behavior of Si₃N₄ ceramics was systematically investigated. Compared with fine particles, coarse particles exhibit a slower phase transition rate and remain intact until the end of SPS. The remaining large-sized grains of coarse α-Si₃N₄ induce extensive growth of neighboring β-Si₃N₄ grains and promote the development of large elongated grains. Noteworthy, an appropriate number of large elongated grains distributed among fine-grained matrix forms bimodal microstructural distribution, which is conducive to superior flexural strength. Herein, Si₃N₄ ceramics with flexural strength of 861.34 MPa and thermal conductivity of 65.76 W m⁻¹ K⁻¹ were obtained after the addition of 40 wt% coarse α-Si₃N₄ powder.     

Effect of zeolitic metal–organic framework on thermal,mechanical, and electrical properties of Ca/Zn-stabilized polyvinyl chloride

In order to enhance the heat stability of polyvinyl chloride (PVC), several heat stabilizing parameters such as metal content, antioxidant percentage, primary-to-secondary antioxidant ratios, stearic-to-acetylacetonate ratio, the amounts of pentaerythritol and β-diketone were studied using oven and Congo red tests. Results indicated that the percentage contribution of the calcium-to-zinc molar ratio in the static heat stability was 60.78%. Due to the synergistic effects of the calcium/zinc stabilizer and the zeolitic metal–organic framework (MOF) as an effective co-stabilizer, the heat stability was increased from 109 to 148 min. The EDX analysis was carried out to determine the mechanism of HCl gas absorption by the zeolitic imidazolate framework-8 (ZIF-8) existing in the PVC compound. Furthermore, the Ca/Zn thermal stabilizer showed poor electrical insulating properties, but the ZIF-8 improved electrical resistivity of the PVC compounds. Volume resistivity of ZIF-8 was significantly higher than that of the commonly used Ca/Zn stabilizers. Dynamic mechanical thermal analysis and tensile test of the PVC compound containing the ZIF-8 showed increased T_g and enhanced toughness.