Applicability of computer simulation to solving of waste and wastewater management,and pollution prevention problems

Concepts and methodologies of model building, modelling and computer simulation are presented. First, analysis of model types, classification and modelling philosophy are outlined. Next, special emphasis is given to the conceptual and technical tools applied in computer simulation. Finally, some examples of computer simulation application to solving of environmental problems are discussed.     

Hydrogen desorption properties of MgH2/LiAlH4 composites

The hydrogen desorption properties of MgH₂–LiAlH₄ composites obtained by mechanical milling for different milling times have been investigated by Thermal Desorption Spectroscopy (TDS) and correlated to the sample microstructure and morphology analysed by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The MgH₂–LiAlH₄ composites show improved hydrogen desorption properties in comparison with both as-received and ball-milled MgH₂. Mixing of MgH₂ with small amount of LiAlH₄ (5 wt.%) using short mechanical milling (15 min) shifts, in fact, the hydrogen desorption peak to lower temperature than those observed with both as-received and milled MgH₂ samples. Longer mixing times of the MgH₂–LiAlH₄ composites (30 and 60 min) reduce the catalytic activity of the LiAlH₄ additive as revealed by the shift of the hydrogen desorption peak to higher temperatures.     

Influence of VO2 nanostructured ceramics on hydrogen desorption properties from magnesium hydride

The hydrogen desorption properties and kinetics of MgH₂–VO₂ composite prepared by mechanical milling of MgH₂ and VO₂ have been investigated. Structural characterization of produced nanocomposite was done by X-ray powder diffraction (XRD), particle size analysis and scanning electron microscopy (SEM). The structure and morphology of the composite have been correlated with hydrogen desorption properties investigated by differential thermal analysis (DTA). It has been shown that short mechanical milling of nanostructured VO₂ and MgH₂ leads to decrease of hydrogen desorption temperature of MgH₂ by 80 K. The mechanism of desorption has been changed from phase boundary reaction, spherical symmetry for untreated MgH₂ to phase boundary reaction, cylindrical symmetry for the composite material. The activation energy for desorption has been reduced by adding VO₂ ceramics as a catalyst.     

Assessment of changes in desorption mechanism of MgH2 after ion bombardment induced destabilization

This paper deals with non-isothermal kinetics models of hydrogen desorption from MgH₂ altered by ion bombardment and stresses the importance of the MgH₂ surface during its decomposition. In the case of argon-irradiated samples, where defects are induced in the near-surface region, the Avrami Erofeev mechanism with parameter n = 2 can be adopted while in the case of boron-irradiated samples, where defects are created deeper in the bulk, the desorption mechanism is the same with n = 3. The difference is possibly related to the concentration and good dispersion of defects in near-surface region in the samples.     

The Influence of Multiple-Solution Annealing on Kinetics of Structural Transformation of Maraging Steels

The paper presents effects of multiple solution annealing on kinetics of structural transformation of maraging steels 18 9 5. Multiple solution annealing testing was carried out in dilatometer by simultaneous registration of transformation temperatures austenite start A_s at heating and martensite start M_s at cooling and registration of linearly dilatatic changes.

Analysis of dilatometric curves has quantified coefficients of dilatation during heating and coefficient of contraction during cooling, and has established mathematical model for determination of quantity of retained austenite in microstructure of maraging steels.     

Acceptability of wine produced with an increased content of grape seeds and stems as a functional food

Owing to a globally increased interest in the relationship between nutrition and health, the development of new functional food products is gaining more importance. The aim of this research was to evaluate the quality and acceptability of a wine produced with increased amounts of grape seeds and stems as a functional beverage. Sensory properties of the wines produced were evaluated and the market potential of this product was estimated through a survey carried out among wine consumers in Novi Sad, Serbia. It was shown that addition of enhanced amounts of grape seeds in the pomace had a greater influence on the phenolic composition and antioxidant capacity towards DPPH and hydroxyl radicals than supplementation with stems. Flavan‐3‐ols and their monomers [(+)‐catechin and (?)‐epicatechin], as predominant phenolic compounds extracted from grape seeds, showed a high positive correlation with antioxidant activity (r ≥ 0.950). Based on the best relationship between phenolic composition and sensory acceptability, the addition of 80 g seeds per kilogram of pomace has been suggested as the most acceptable quantity. The survey showed the necessity for promoting the health‐beneficial effects of catechins through various channels, despite the high percentage of respondents (68%) who were willing to pay up to two times more for this functionally enhanced wine. The major obstacle to the official acceptance of this wine as a functional beverage in Serbia is the insufficiently examined question of the effect of moderate alcohol intake on health. Copyright © 2014 The Institute of Brewing & Distilling