Fine milling in applied mechanochemistry

This review paper is devoted to application of mechanochemistry in extractive metallurgy, crystal engineering, materials engineering, coal industry, building industry, agriculture, pharmacy and waste treatment. In extractive metallurgy the most commercially attractive potential applications using fine milling (Activox, Melt) will be illustrated. Mechanochemical approach in crystal and materials engineering will focus on the non-equilibrium processing of materials and their current and potential applications. In agriculture the technological advantages of mechanochemical methods over traditional methods for improving the solubility of natural phosphates will be documented. In pharmacy, the selected examples of fine milling application will show the improved bioavailability of drugs. The examples of fine milling utilization in coal industry, building industry and waste treatment are also given. Simplification of the processes, ecological safety and the product extraordinariness characterize the application of fine milling in mechanochemistry.     

Aromatic hydroxylation is a major metabolic pathway of the mycotoxin zearalenone in vitro

Zearalenone (ZEN) is a common mycotoxin, for which only reductive metabolites have been identified so far. We now report that ZEN is extensively monohydroxylated by microsomes from human liver in vitro. Two of the major oxidative metabolites arise through aromatic hydroxylation and are catechols. Their chemical structures have been unambiguously determined by using deuterium‐labeled ZEN and by comparison with authentic reference compounds. Moreover, both catechol metabolites of ZEN were substrates of the enzyme catechol‐O‐methyl transferase. One of the monomethyl ethers represented the major metabolite when ZEN was incubated with rat liver slices, thus demonstrating that catechol formation also takes place under in vivo‐like conditions. Out of ten major human cytochrome P450 (hCYP) isoforms only hCYP1A2 was able to hydroxylate ZEN to its catechols with high activity. Catechol formation represents a novel pathway in the metabolism of ZEN and may be of toxicological relevance.     

Determination of antioxidant compounds and antioxidant activity in commercial oilseeds for food use

Different commercial edible oilseed samples were analyzed in order to evaluate the compounds involved in antioxidant activity. Fatty acids, triacylglycerols, tocopherols, chlorophylls, β-carotene, squalene, phenolic compounds and CIE L^∗a^∗b^∗ coordinates were assayed. Strong chemical variability depending on the oilseed variety was observed. Antioxidant activity was evaluated for the oils, both for their methanol-soluble phase and the fraction insoluble in methanol. DPPH radical scavenging activity expressed in TEAC ranged between 0.45 and 2.30 mmol/l in peanut and maize oils, respectively. Free radical scavenging activity was mainly influenced by tocopherols content (r = +0.70) in oils and polyunsaturated fatty acids (r = +0.61) in the fraction nonsoluble in methanol. Variability of the correlation between the antioxidant activity and the composition of the oilseeds could be attributed to the differences in the squalene, chlorophylls, carotenoids, and phenols contents of the oils and their mutual interactions.     

Effects of milling on co-precipitated 3Y-PSZ powders

The present research compares properties and behaviour of co-precipitated 3Y-PSZ powders submitted, after co-precipitation, to different milling treatments. The characteristics of the different products were evaluated by measurement of particle size distribution, thermogravimetric analysis, X-ray diffraction, specific surface area and scanning electron microscopy analysis. It has been demonstrated that 1 h of attrition milling enables the production of powders containing soft agglomerates of nanometric particles: the dispersing liquid used on milling has little influence. Crystallisation into a cryptocrystalline structure of the amorphous powder is achieved after 1 h of high energetic milling, avoiding thermal treatments.     

Fat content and fatty acid composition of oils extracted from selected wild-gathered tropical plant seeds from Nigeria

As the search for alternative sources of food to alleviate hunger continues, this study was undertaken to determine the fat content and the fatty acid composition of 15 lesser-known wild tropical seeds gathered in Nigeria. Results were contrasted with five tropical soybean varieties (Glycine max). The fat content varies from less than 1% (Pterocarpus santalinoides, Daniellia ogea) to 59% (Entandrophragma angolense). The fatty acid composition of most of the wild and mostly leguminous seeds differed considerably, compared to the composition of tropical soybeans. The oil of Adansonia digitata, Prosopis africana, Afzelia lebbeck, Enterolobium cyclocarpium, and Sesbania pachycarpa contained high proportions of linoleic and oleic acid as well as palmitic and linolenic acid. Seeds of Milletia thonningii, Lonchocarpus sericeus, and S. pachycarpa were much higher in linolenic acid and relatively poor in linoleic acid, compared to soybeans. The content of saturated fatty acids was higher than that of soybeans, resulting in lower polyunsaturated/saturated (P/S) ratios (0.83–2.12) than observed in soybeans (P/S=3.4), with the exception of the composition of S. pachycarpa (P/S=3.15). Some of these less familiar wild seeds could be used as sources for industrial or edible oils, provided that possible toxic constituents could be removed.     

Heap-abstraction for an object-oriented calculus with thread classes

This paper formalizes an open semantics for a calculus featuring thread classes, where the environment, consisting in particular of an overapproximation of the heap topology, is abstractly represented. From an observational point of view, considering classes as part of a component makes instantiation a possible interaction between com- ponent and environment or observer. For thread classes it means that a component may create external activity, which influences what can be observed. The fact that cross-border instantiation is possible requires that the connectivity of the objects needs to be incorporated into the semantics. We extend our prior work not only by adding thread classes, but also in that thread names may be communicated, which means that the semantics needs to account explicitly for the possible acquaintance of objects with threads. We show soundness of the abstraction. Part of this work has been financially supported by the NWO/DFG project Mobi-J (RO 1122/9-4), by the DFG project AVACS (SFB/TR-14-AVACS), by the EU-project IST-33826 Credo: Modeling and analysis of evolutionary structures for distributed services (see )     

Microstructural simulation of phase decomposition in Cu–Ni alloys

The microstructure simulation of spinodal decomposition was carried out in the aged Cu–70 and 90 at.% Ni alloys, based on a solution of the non-linear Cahn–Hilliard partial differential equation by the finite difference method. The calculated concentration profiles were compared with the experimental ones determined by atom-probe field ion microscope analyses of the solution treated and aged Cu–70 at.% Ni alloy samples. Both the numerically simulated and experimental results showed a good agreement for the concentration profiles and microstructure evolution in the aged Cu–Ni alloys. A very slow growth kinetics of phase decomposition was observed to occur in this type of alloy. The morphology of decomposed phases consists of an irregular shape with no preferential alignment in any crystallographic direction. The wavelength of composition modulation was determined numerically to be about 2 nm and it remained constant after aging at 573 K for times as long as 8889 h. No phase decomposition was observed to occur for the numerical simulation of aging at temperatures lower than 523 K for a time as long as 1 year.     

Study of calcite scaling and corrosion processes in geothermal systems

Prediction of scaling in geothermal systems is important in order to be able to take preventive action. Scaling and corrosion processes are correlated in geothermal systems so that the factors influencing both processes are discussed in this paper. Pilot-scale equipment to model dissolution and scaling, and investigate corrosion, has been constructed. The construction of the pilot-scale equipment and the design of the experiments were based on the results of earlier laboratory model experiments. In order to check the measurement results we used a computer programe that was developed earlier, and which is suitable for the calculation of the equilibrium solubilities. Based on the results of the equilibrium experiments, we developed a modelling method for scaling in the pilot-scale equipment, and studied corrosion during scaling on the surfaces of five different structural materials.     

Efficacy of surface applications with diatomaceous earth to control Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) in stored wheat

Commercial formulations of diatomaceous earth (DE) products labeled for use as grain protectants usually specify on the label the depth for using them as a surface treatment, which is often 30.5 cm. An experiment was conducted at two temperatures (27 and 32 °C) and three exposure intervals (7, 10 and 14 d), at a relative humidity of 57–60% to determine if Rhyzopertha dominica (F.), the lesser grain borer, could penetrate a 30.5-cm layer of wheat treated with the labeled rates of three commercial formulations of DE, and, if so, to measure rates of adult survival and progeny production. When R. dominica adults were introduced to this surface layer of 30.5-cm wheat admixed with DE, they were able to penetrate the DE-treated layer and oviposit in the untreated wheat below. Both adult survival and progeny production were significantly lower in wheat with a surface-layer treatment of Dryacide^® (1000 ppm) as compared to Insecto™ (500 ppm), Protect-It^® (400 ppm) or the untreated control. Temperature and exposure interval had no effect on adult survival or progeny production. The vertical displacement patterns of adults were significantly different among DE treatments, but not for temperature or exposure intervals. More R. dominica traveled a greater distance in the untreated control, followed by Insecto™, Protect-It^®, and then Dryacide^®. Results indicate that R. dominica can penetrate a surface layer of DE-treated wheat and reproduce within and below it, but it is possible that pest suppression is dose dependent, or it may depend on a combination of application rate and specific DE formulation.     

Effect of the addition of calcium hydroxide on some characteristics of extruded products from blue maize (Zea mays L) using response surface methodology

The aim of this research was to study the effects of calcium hydroxide (0–0.2%) and screw speed (100–180 rpm) on the expansion index (EI), bulk density (BD), penetration force (PF) and specific mechanical energy (SME) values of blue maize meal extrudates. Blue maize meal was extruded using a commercial extruder (Brabender 20DN/8‐235‐00) with a compression screw ratio of 3:1. A second‐order, central composite experimental design was used. It was found that the EI and SME values decreased and the BD and PF values increased when the calcium hydroxide concentration was increased. The screw speed had a significant effect only on the SME and PF values. Quadratic model fitness was shown for all responses, with values of R² > 0.74, p of F (model) <0.01 and variability coefficient <13.3% (except for PF, 29.18%), and for almost all cases there was no lack of fit (p > 0.055). Calcium hydroxide concentration showed good correlation (p < 0.01) with EI (r = ?0.81), PF (r = 0.60), SME (r = ?0.76) and BD (r = 0.83). However, screw speed was marginally or not correlated (r < 0.36, p > 0.14) with the responses. The results suggest that it is possible to produce appropriate extruded products from blue maize fortified with calcium in an optimised calcium hydroxide concentration and screw speed range of 0.02–0.078% and 117–180 rpm respectively. © 2001 Society of Chemical Industry