Amount Of Sol Research Articles

Improving the Durability of Lime Finishing Mortars by Modifying Them with Silicic Acid Sol.

Lime materials are in great demand for the restoration of the walls of historical buildings. However, lime coatings have insufficient resistance during operation. The purpose of this work was the modification of lime mortars with silicic acid sol in order to obtain more durable crystalline materials for construction purposes. A technology has been developed for obtaining a silica-containing additive, which consists in passing a liquid glass solution with a density of 1.053 kg/m3 through a cationic column and obtaining a silicic acid sol with a pH of 3–4 and a charge of (−) 0.053 V. The regeneration time and the amount of sol have been determined. Regularities of change in the radius of particles of silicic acid sol depending on age are determined. It is established that at an early age (up to 5 days), the radius of sol particles can be determined in accordance with the Rayleigh equation, and at a later age, in accordance with the Heller equation. The results of the calculation show that at the age of 1–5 days, the radius of the sol particles is 17.1–17.9 nm, and then the particles become coarser and the particle radius is 131.2–143 nm at the age of 19 days. The work of adhesion of silicic acid sol to lime and the heat of wetting are estimated. It is shown that the work of adhesion of water to lime is 28.9 erg/cm2, and that of the sol is 32.8 erg/cm2. The amount of heat Q released when lime is wetted with SiO2 sol is 15.0 kJ/kg, and when lime is wetted with water, it is 10.6 kJ/kg.

Preparation of Sol-Enhanced Ni–P–Al2O3 Nanocomposite Coating by Electrodeposition

A Ni–P–(sol)Al2O3 coating was prepared on the surface of Q235 steel by direct-current electrodeposition. This method was combined with sol-gel and electrodeposition technique, instead of the traditional nanopowder dispersion, to prepare highly dispersible oxide nanoparticle-reinforced composites. The effects of temperature, pH value, and current density and Al2O3 sol on the hardness of composite coating were investigated. The coating surface morphology and structure were characterized by scanning electron microscopy and energy dispersive spectroscopy, respectively. The corrosion resistance of coatings in the presence of intermediate layers was evaluated by electrochemical measurement in 3.5% NaCl solution by open-circuit potential measurement at room temperature. The hardness and wear resistance of the coating were measured by a microindentation instrument and friction wear machine, respectively. The results showed that Al2O3 sol can effectively improve Ni–P alloy coating structure and refine grain. When the bath temperature was 55°C, the pH value was 4.5, the amount of sol was 80 mL/L, the current density was 1 A/dm2, and the hardness of the nanosol coating was 569 HV. Compared with Ni–P, the friction coefficient increases slightly, but the wear rate was only 1.768×10−6 g·m−1. The corrosion resistance was also better than that of Ni–P coating.

Structure and Properties of the Modified Binding for Silicate Paints

Information is provided about the stability of polysilicates solutions, obtained by mixing liquid glass and silica sol. It was found, that at increases the amount of silicic acid sol added, the pH of the solutions decreases with an unchanged alkali concentration. Information on the structure of polysilicate solutions are given. It has been found, that addition of the sol (increasing the silicate module) contribute to prolonging fraction of high-polymer fractions of silicic anion. The dependence of the silica content of the monomeric form of α-SiO2in the early stages of interaction between the sol and liquid glass is extreme. The maximum content of α-SiO2 depends on the type of liquid glass and the amount of sol. It is shown, that films based on polysilicates solutions, are characterized by faster curing. The manifestation of the scale factor for coatings based on polysilicate solutions was revealed.

Effect of Ferrous Additives on Magnesia Stone Hydration

The article deals with the modification of the magnesia binder with additives containing two- and three-valent iron cations which could be embedded in the chloromagnesium stone structure and also increase the strength from 60 MPa in a non-additive stone to 80MPa, water resistance from 0.58 for clear stone to 0.8 and reduce the hygroscopicity from 8% in the non-additive stone to 2% in the modified chloromagnesium stone. It is proposed to use the iron hydroxide sol as an additive in the quantities of up to 1% of the weight of the binder. The studies were carried out using the modern analysis methods: the differentialthermal and X-ray phase analysis. The structure was studied with an electron microscope with an X-ray microanalyzer. A two-factor plan-experiment was designed which allowed constructing mathematical models characterizing the influence of variable factors, such as the density of the zatcher and the amount of sol in the binder, on the basic properties of the magnesian stone. The result of the research was the magnesia stone with the claimed properties and formed from minerals characteristic for magnesian materials as well as additionally formed from amachenite and goethite. It has been established that a highly active iron hydroxide sol the ion sizes of which are commensurate with magnesium ions is actively incorporated into the structure of pentahydroxychloride and magnesium hydroxide changing the habit of crystals compacting the structure of the stone and changing its hygroscopicity.

Investigation of the influence of the amount of ethylsilicate, sol based on it and phenol-formaldehyde resin on the strength properties of non-pergarnic magnesia carbon refractories

Using the full factorial experiment, the influence of the number of modifiers: ethylsilicate (Z1 = 0.5 − 1.5 %), sol based on it (Z2 = 0.25 − 0.75 %) and liquid phenol formaldehyde resin (Z3 = 3.0 − 4.0 %) on the strength of periclase-carbonaceous materials. It has been established that in order to obtain strong non-perliquid periclase-carbon refractories, the maximum amount of phenol-formaldehyde resin (4 %), ethylsilicate (1.5 %) and the minimum amount of sol based on ethylsilicate (0.25 %) should be included in the charge composition.

Investigating the effect of molar ratio between TiO2 nanoparticles and titanium alkoxide in Pechini based TiO2 paste on photovoltaic performance of dye-sensitized solar cells

Recombination of electrons in TiO2 conduction band has detrimental effects on the performance of dye-sensitized solar cells (DSSCs). Good connection between TiO2 nanoparticles, in meso-porous TiO2 layer, causes a significant reduction in recombination reaction rate. In the present work, Pechini sol–gel method was used for the synthesis of TiO2 nanoparticle pastes with different amounts of titanium tetra-isopropoxide (TTIP) in their sol precursors. The synthesized paste was used for the fabrication of photoanode of DSSCs. Then, the effect of TTIP content of sol precursor on the photovoltaic performance of DSSCs was investigated. For all pastes, the amount of sol in paste was kept constant which led to the meso-porous TiO2 layers with the same amount of porosity. Results showed that the photovoltaic performance of DSSCs first increases and then decreases with increasing TTIP content of sol precursor. It was concluded that the increase in performance of DSSC is due to the good connection between TiO2 nanoparticles and the decrease in performance is due to the micro-cracks in the meso-porous TiO2 layers with high content of TTIP in their sol precursor.

Sample Preparation Methods for the Determination of the Antioxidative Capacity of Apple Juices

The elevated ecological awareness nowadays led to a higher consumption of apples juices. Apples juices are rich in dietary fiber, pectin, potassium, and vitamins A and C as well as in different classes of phenolic compounds, which can protect the human body against oxidative stress by scavenging oxygen free radicals. During production and storage some bioactive compounds might decompose result- ing in a reduced antioxidative capacity. Common methods for the determination of the antioxidative capacity of other food stuff are based on the extraction of the compounds under study using acetone, which is senseless in aqueous juices. But acetone might have an influence on the compounds responsible for the antioxidative capacity. Thus, self made apple juice samples were analyzed without organic solvent as well as mixed with acetone to see differ- ences caused by the solvent. The results obtained with both procedures were compared using a paired t-test in order to see statistically significant differences in the results. No statistically significant differences were found between the testing with and without acetone. Thus the time of analysis, the amount of sol- vents needed, and the required labor force can be reduced without loosing analytical quality. Total content of phenolic compounds ranged from 400 to 650 mg gallic acid equivalent / L (Folin-Ciocalteu method) and antioxidative capacity from 1.0 to 1.6 mmol Trolox ® / L (ABTS assay). (doi: 10.5562/cca1756)

Effects of Boron and Nitrogen on Graphitization and Hardenability in 0.53%C Steels

The effects of B and N on the graphitization and the hardenability in 0.53 mass% C steels were investigated in order to utilize both effects of BN and free B on the properties of machine structural steels. The number of BN particles after normalizing heat treatment is increased by the increase in the amount of B or the decrease in N. In the steel that has lower content of N, BN can be resolved and finely precipitates during normalizing. BN provides the preferred site for graphite nucleation, so the distribution of graphite particles is very similar to that of BN prior to graphitization. The growth rate of graphite particle is controlled by diffusion of carbon in ferrite matrix, and the time required for completion of the graphitization is the function of the radius of graphite particles after the end of graphitization, which depended upon the number of graphite particles. The hardenability of the steels can be estimated by the amount of sol. B at heating temperature prior to quenching. Sol. B of 6 ppm or more is required to obtain full martensitic microstructure. The preferable graphite distribution and the enough hardenability of the steels can be simultaneously achieved by optimizing the heating process and the amount of boron and nitrogen.

Novel polyisobutylene/poly(dimethylsiloxane) bicomponent networks. II. Network structure and property characterization

The first part of this series concerned the synthesis of novel polyisobutylene (PIB)/poly(dimethylsiloxane) (PDMS) bicomponent networks; the present paper concerns the structure and property characterization of a series of bicomponent networks of varying compositions (PIB wt %/PDMS wt % = 92/8, 70/30, 50/50, 35/65) having average molecular weights between crosslinks (Mc) of ˜ 20,000 g/mol. According to network structure analysis by uniaxial equilibrium stress–strain measurements, the experimental Mc's are in excellent agreement with theoretical values. Hydrosilation end-linking efficiency was quantitated by the amount of sol and functional group analysis by 1H-NMR spectroscopy. NMR evidence indicates double-bond isomerization during hydrosilation. Network compositions by elemental analysis together with the low sol fractions indicate efficient crosslinking. These data suggest highly efficient network formation and well-defined bicomponent network structures. While PIB and PDMS showed Tg's at −72 and −124°C, respectively, the bicomponent network did not exhibit clearly discernible phase transitions. The heat stability of bicomponent networks increased slightly with increasing PDMS content showing initial (10%) degradation temperatures at ˜ 380°C in nitrogen and ˜ 320°C in air. Tensile strengths and elongations were dependent on composition and varied in the 0.6–3.8 MPa and 600–1100% ranges, respectively. The swelling behavior was not much affected by composition. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1901–1910, 1998

Effect of poly(acrylic acid) on the preparation of thick silica films by electrophoretic sol–gel deposition of re-dispersed silica particles

Thick silica films were prepared by the electrophoretic sol–gel deposition technique in the presence of poly(acrylic acid) (PAA) using monodispersed silica particles; the particles were prepared by the sol–gel method, pre-heat treated and then re-dispersed in the mixture of H2O and ethanol. The weight of deposited silica films was maximized when 0.2 mass % of PAA against the whole amount of sol was added. The particles constructing the thick silica films were packed densely when the amount of added PAA was less than 0.2 mass%. The weight of the film increased with decrease in the content of H2O in the sol when a fixed amount of PAA was added. After the heat treatment of deposited films at 800 °C, crack-free silica films of about 30 μm thickness were prepared. © 1998 Chapman & Hall

Algal primary production in a dredged sludge disposal site

Abstract In this report, the CODMn amount produced in the stabilization pond of a dredged sludge disposal site was estimated and discussed. In the AGP (Algal Growth Potential) test of the effluent from the stabilization pond, Skeletonema costatum and Chlorella sp. grew to the cell density of 350,000 (cells)mL−1 (p‐CODMn. 2.1 mgL−1) and 240,000 (cells)mL−1 (p‐CODMn, 10.0 mgL−1), respectively. It was found also these values were increased by addition of the solution of materials from benthal mud and treated wastewater from Site 1 (aerated lagoon). The calculated amount of CODMn produced in the stabilization pond was highest in spring, ranging from 6.8 to 172.7 ton(month)−1. Most of the CODMn amount produced was precipitated, degraded and taken up by Zooplankton in the stabilization pond, and 0.9 to 5.6 ton(month)−1 as p‐CODMn and 4.0 to 6.2 ton(month)−1 as sol. CODMn were discharged. The amount of sol. COD discharged was almost constant throughout the year, which indicated that the CODMn amount lost from th...

Nb添加熱延鋼板の機械的性質におよぼすSol. Nb量の影響

Nb添加熱延鋼板の機械的性質におよぼすSol. Nb量の影響

The structure and elasticity of polyurethane networks

Model networks prepared from polyoxypropylenetriols (PPT) and diphenylmethane diisocyanate (MDI) in an excess of NCO groups were found to contain unusually small amounts of sol, ws, and to have high values of the equilibrium modulus, suggesting an additional crosslinking, probably due to the formation of trifunctional allophanate crosslinks. A comparison of the ws values with the theory of branching processes in which the formation of both urethanes and allophanates is considered allowed us to determine the possible extent of the allophanate reaction, and to calculate the concentration of elastically active chains contributed by PPT and allophanate crosslinks.

Correspondence between the theory of branching processes and the kinetic theory for random crosslinking in the post-gel stage

The kinetic theory of crosslinking by step reactions (Kuchanov 1978) may be extended beyond the gel point, and the structure and amount of sol may be described. For random reactions, the kinetic theory yields results identical with the theory of branching processes based on cascade substitution (Gordon 1962, 1975, Dobson 1965). The extension of the kinetic theory may be employed in order to compare deviations between the two theories expected for the dependent reactivities of functional groups.

Corneal Vascularization in Rats on a Tryptophane Deficient Diet

Montmorillonite goes readily into solution in slightly acid water. In strong acids only bases, in pure water only free silica is removed. In the range from 0.02 to 0.5 per cent. acid, both bases and silica go into solution and recombine as an aluminosilicate sol and as highly soluble salts. The sol recovered by evaporation, washing and drying is an amorphous colloid near pyrophyllite in composition, Al(2)O(3).mSiO(2).nH(2)O, with m averaging 4.1 (3.9 to 4.5) and n about 1.5. The slight variation in m is unrelated to either sol, acid or clay concentration. A general characteristic relation between the amount of sol formed and the amounts of clay, acid and water used has been found for montmorillonite clays. This relation differs in two essential properties from that previously deduced for halloysite-allophane solutions. The variation with temperature of the constants of these equations remains to be investigated.

Sol and Gel in Hevea Latex and Crude. Rubber Influence of Oxidation on Gel-Sol Transformation

Abstract An apparatus and procedure to determine the amounts of sol and gel rubber in dried latex films and crude rubber have been described. It is shown that whereas plantation smoked sheet and crepe contain large and varying quantities of rubber soluble in petroleum ether, dried rubber films from latex are practically free from sol rubber when oxidation has been avoided. Latex increases in sol rubber content when subjected to various treatments permitting oxidation of the hydrocarbon. It appears from this work that the rubber in the form of latex is very susceptible to oxidation, which however involves only minute quantities of combined oxygen. When latex film rubber is subjected to creeping, it shows an increased content of sol rubber corresponding to that of crepe. A short milling of crepe was found to convert it completely into sol rubber. This confirms the gel-sol transformation mechanism of breakdown. Gel rubber from dried latex films is swelled to a maximum of 1500 to 7800 per cent but is not dissolved when placed in benzene, chloroform, carbon tetra-chloride or carbon disulfide and allowed to stand for several days. Gel rubber becomes soluble and therefore diffusible in these solvents as a result of oxidation. It was found that dried latex film and various types of crude rubber swelled to a maximum of 1000 to 2400 per cent in petroleum ether and that this swelling was not proportional to the sol content. This investigation strengthens the belief that sol rubber is an oxidation product of gel rubber. The formula for sol rubber is suggested as (C5H8)nO2, and a relationship between the molecular weight and the oxygen content is postulated on the basis that oxygen acts as a molecular splitting agent for both gel and sol.