Effect of chemical phosphorylation on solubility of buffalo milk proteins

Buffalo milk proteins (casein, co-precipitate or whey protein concentrate) were phosphorylated with phosphorus oxychloride (POCl₃) at three different pH values (5.0, 7.0 and 9.0). The solubilities of phosphorylated milk proteins were examined over the pH range 3.0–9.0 in water and ionic (0.1 m NaCl or 10–70 mm Ca²⁺) systems. The solubilities of buffalo milk proteins decreased at pH 3.0, while there was an increase in the solubilities of casein and co-precipitate near their isoelectric points upon phosphorylation. Solubilities of these phosphorylated milk proteins were pH dependent in 0.1 m NaCl but there was a decrease in their solubilities with increase in calcium ion concentration. This alteration could be due to the shifting of isoionic points of phosphorylated buffalo milk proteins towards acidic pH.     

Oil agglomeration of a lignite treated with microwave energy: Effect of particle size and bridging oil

Oil agglomeration of Sivas–Divriği (S–D) Uluçayır lignite fines was carried out using kerosene and kerosene–extract oil (which was obtained from lignite treated with microwave energy) mixture as a bridging oil. The effects of parameters such as the amount and type of bridging oil, microwave time and particle size on the agglomeration performance were investigated. The amount of kerosene was varied from 5 to 30 wt.% of the initial lignite loading. The values of the grade and recovery increased with an increase in the amount of kerosene added. Extract oil fraction of the lignite extract at various ratios in kerosene increased the agglomeration recovery from 95.88% to 98.55%. The effect of microwave time was investigated and it was found that the grade was also increased with increasing microwave time (4, 8 and 10 min). The grade of char (microwave time: 8 min) was increased in comparison with the original lignite while decreasing its recovery. Dense medium separations of the lignite were conducted and the results of their grade recovery performances were compared with those of agglomeration of the particles. During the inspection of particle size effect on the dense medium separation, the recovery was increased remarkably (from 12.07% to 89.50%) with increasing particle size, while decreasing the grade (from 0.732 to 0.697). In the oil agglomeration of lignite the recovery values were increased with increasing particle size.     

Synthesis and properties of cinnamic acid series organic UV ray absorbents–interleaved layered double hydroxides

Organic ultraviolet (UV) ray absorbents, cinnamic acid (CA) and p-methoxycinnamic acid (PMOCA) were intercalated into Zn₂Al layered double hydroxides (Zn₂Al-LDHs) by co-precipitation reaction. The organic–inorganic nanocomposites, Zn₂Al-LDH/CA and Zn₂Al-LDH/PMOCA were obtained. The samples showed excellent UV ray absorption ability and their catalytic activity for the air oxidation of castor oil greatly decreased when the organic UV ray absorbents were intercalated in the layers of the Zn₂Al-LDHs. The studies suggested that Zn₂Al-LDH/organic UV absorbent nanocomposites might be used as safe sunscreen materials.     

Friction-transfer test for the assessment of in situ strength and adhesion of cementitious materials

Since in concrete industry, the quality control is generally accomplished by the testing of separately prepared samples, the accurate estimate of the in situ strength of concrete has become a necessity. The main discrepancies between the measured cube strength and the actual in situ strength of concrete, relates to their different conditions associated with the development of strength. In addition, due to chemical deterioration or damage, accurate estimate of in situ concrete strength provides valuable information about the present situation of the structure, when making decisions about the required repair and/or strengthening systems. The Friction-Transfer method, which is described in this paper, can be used to estimate the in situ strength of concrete and other materials. In this method a specially devised apparatus fits on to the top of the partial core and is clamped to it. To measure the concrete compressive strength, a torque is applied using an ordinary torque-meter and the maximum shear stress at failure is used to estimate the cube compressive strength by means of a calibration graph. In order to measure the adhesion between different layers of cementitious and/or resinous materials, their torsional shear strengths are calculated along the failed inter-facial surfaces of the layers. Laboratory and in situ tests, to evaluate the performance of the method are described. Also in view of the accurate and reliable results attainable, some specific applications are proposed.     

HPLC–MS analysis of the green food colorant sodium copper chlorophyllin

Five commercial samples of sodium copper chlorophyllin, a green food colorant, were analysed by high-performance liquid chromatography (HPLC) using diode-array detection (DAD) and mass spectrometry (MS). Some of the constituents were identified using authentic standards, whereas others were identified tentatively based on their absorption spectra and mass data. The composition of three of the samples was very similar, whereas the other two were quite different. In the three former samples, the three largest peaks could be assigned to Cu chlorin e₆, Cu chlorin p₆, and Cu isochlorin e₄. In one of the two other samples, these three compounds were also among the largest peaks, whereas Cu chlorin e₆ was a small peak in the last sample and Cu chlorin p₆ was absent altogether. Porphyrins were also present in the samples, while except in one of the samples chlorins derived from chlorophyll b were largely absent.Industrial relevanceSodium copper chlorophyllin is a green food colorant made from chlorophyll. Sodium copper chlorophyllin is made by saponifying chlorophyll and coppering the resulting product. This processing leads to a complex mixture of compounds. An analytical method was developed that can be used to identify many of these compounds and show the extent of coppering and degradation of sodium copper chlorophyllin, which may be used industrially to optimize the production of sodium copper chlorophyllin.     

Bonelike apatite formation on carbon microspheres

Carbon microspheres with a diameter of 2 μm were prepared by hydrothermal process. The apatite-formation ability of the carbon microspheres was evaluated by soaking them in a simulated body fluid (SBF) for 5 and 10 d and apatite-formation mechanism was also analyzed. The result showed that bonelike apatite was formed on the surface of carbon microspheres. Our study indicates that the carbon microspheres synthesized by this method possess apatite-formation ability and may be used as a bioactive injectable filler for bone tissue regeneration.     

Effect of charge trapping species of cupric ions on the photocatalytic oxidation of resorcinol

The photocatalytic oxidation of resorcinol, a potent endocrine disrupting chemical, in oxygenated aqueous suspensions of pure and cupric ions modified Degussa P25 titanium dioxide has been investigated at pH 3.0 ± 0.5. The initial rate of photocatalytic oxidation of resorcinol increased until an optimum dissolved cupric ions concentration was reached at 1.04 mM. At the optimum concentration of cupric ions, the initial rate of photocatalytic mineralisation and degradation of resorcinol was improved by 400%. The observed beneficial effect of cupric ions on the initial rate of resorcinol oxidation could be attributed to the formation of complex and its participation in the photoredox cyclic reaction.Two of the initial oxidation intermediates detected were 1,2,3-trihydroxybenzene and 1,2,4-trihydroxybenzene. These intermediates were formed via hydroxylation of the aromatic ring of resorcinol. Evidences have revealed that 1,2,4-trihydroxybenzene interacted strongly with cupric ions forming copper(II)-trihydroxybenzoate complexes that possessed good adsorption onto TiO₂ surface. These dual-effects help to draw the metal ions closer to the photocatalyst surface and subsequently trigger the electron trapping mechanism by cupric ions. As a result, this improved the charge carriers’ separation. Furthermore, in the presence of oxygen, reoxidation of photoreduced cupric ions occurred and this eliminated the possibility of copper photodeposition, while inducing a photoredox cyclic reaction to regenerate copper species that may potentially act as co-catalyst for the oxidation of 1,2,4-trihydroxybenzene. In contrast, no obvious complex formation was seen between 1,2,3-trihydroxybenzene and cupric ions. This pointed to an intriguing finding which indicates that the positioning of functional group on benzene ring influences the role of cupric ions.     

Frictional assessment of magnesium stearate and palmitate lubricant powders

A method has been developed for the frictional assessment of powder lubricants using a shear-box tester similar to that employed by Jenike. One commercial magnesium stearate, three high-purity magnesium stearates and three high-purity magnesium palmitates were assessed using this method. Powders with a well-ordered crystal structure and particle shape have a lower initial maximum coefficient of friction μ_a. The difference between μ_a and μ_b, the equilibrium dynamic friction coefficient, gives an indication of lubricant film-forming propensity. The basic friction equation is obeyed by the powders for most of the load range studied but deviates slightly approaching zero normal load.