Influence of thermal cycling treatment on the anneal hardening effect of Cu–10Zn Alloy

This paper reports the results of investigations on the influence of the so called thermal cycling treatment on the anneal hardening effect of the copper-based Cu–10 at.% Zn alloy. The quenched samples were subjected to cold rolling of 20, 40 and 60% in reduction, followed by annealing with and without thermocycling treatment below the recrystallization temperature. Anneal hardening effect was observed in both samples in the temperature range between 180 and 300 °C and was followed by an increase in the hardness and electrical conductivity. These investigations showed that the thermal cycling treatment some increased the intensity of anneal hardening effect.     

Absolute Determination of the Gelling Point of Gelatin under Quasi‐thermodynamic Equilibrium

Thermodynamic studies on phase transformation of biopolymers in solution are useful to understand their nature and to evaluate their technological potentials. Thermodynamic studies should be conducted avoiding time‐related phenomena. This condition is not easily achieved in hydrophilic biopolymers. In this contribution, the simultaneous effects of pH, salt concentration, and cooling rate (Cr) on the folding from random coil to triple helical collagen‐like structures of gelatin were systematically studied. The phase transformation temperature at the absolute invariant condition of Cr = 0 °C/min (T_T^Cr=0) is introduced as a conceptual parameter to study phase transformations in biopolymers under quasi‐thermodynamic equilibrium and avoiding interferences coming from time‐related phenomena. Experimental phase diagrams obtained at different Cr are presented. The T_T^Cr=0 compared with pH and T_T^Cr=0 compared with [NaCl] diagram allowed to explore the transformation process at Cr = 0 °C/min. The results were explained by electrostatic interactions between the biopolymers and its solvation milieu.     

Phenol content,antioxidant activity and metal composition of Croatian wines deriving from organically and conventionally grown grapes

The present study was performed to evaluate the antioxidant capacity, the polyphenol and metal content of conventionally and organically produced wines, which underwent similar winemaking processes. The wine grapes were grown under well-defined organic and conventional conditions from the two different wine-growing sub-regions of Croatia, Prigorje and Southern Dalmatia. The values of antioxidant activity, as evaluated by two free radical methods, ABTS and DPPH, was found systematically higher in organic wines compared to conventional ones. In a reversed phase HPLC analysis, used in order to characterise the phenol fraction of wines, higher concentrations of chlorogenic acid, ferulic acid, catechin, trans-resveratrol, all studied hydroxybenzoic acids and flavonols were found in the organically produced wines. No apparent trend was found in the metal contents of the wines, but ICP-MS analysis confirmed that both wine productions, organic and conventional, were well within the toxicological safety limits.     

Metals in organic and conventional wheat flours determined by an optimised and validated ICP‐MS method

This study was undertaken (i) to optimise and validate a suitable method for multi‐element determination in cereal products and (ii) to evaluate multi‐element content differences in commercially available conventional vs. organic wheat flours. Presented ICP‐MS method is simple and accurate for the determination of eighteen elements in cereal food. Obtained results show differences in metal content between conventional and organic wheat flours and confirm that both types of production are well within the toxicological safety limits regarding the metal contents. The significant differences among conventional vs. organic wheat flours were obtained for As, Cd, Cr, Fe, Mg, Mo, Ni and V. Toxic metals (Al, As, Cd and Pb) input was higher in conventional compared with organic wheat flours. However, further and long‐term research is needed to clearly underline the effects of organic agricultural practice on the quality of food products.     

Data dissemination in wireless broadcast channels: Network coding versus cooperation

Network coding and cooperative diversity have each extensively been explored in the literature as a means to substantially improve the performance of wireless networks. Yet, little work has been conducted to compare their performance under a common framework. Our goal in this paper is to fill in this gap. Specifically, we consider a single-hop wireless network consisting of a base station and N receivers. We perform an asymptotic analysis, as N → ∞, of the expected delay associated with the broadcasting of a file consisting of K packets. We show that if K is fixed, cooperation outperforms network coding, in the sense that the expected delay is proportional to K (and thus within a constant factor of the optimal delay) in the former case while it grows logarithmically with N in the latter case. On the other hand, if K grows with N at a rate at least as fast as (logN)^r, for r ≫ 1, then we show that the average delay of network coding is also proportional to K and lower than the average delay of cooperation if the packet error probability is smaller than 0.36. Our analytical findings are validated through extensive numerical simulations.     

Multimorphing: A tool for shape synthesis and analysis

Morphing is a shape transformation where the shape of one object is deformed to the shape of the other object. It is used as an animation or a modeling technique. Classical morphing operates between two input objects but this concept can be extended to multiple input objects – the so called multimorphing. Shapes generated by the multimorphing form a space of shapes motivated by an affine space. Besides the analogy with an affine space we also introduce an inner product and a concept of an orthogonal projection. We also show how to explore space of shapes and how to systematically generate new shapes. The paper focuses on the boundary representation, although some ideas are more general and can be used for other representations, too.     

Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound

Concurrent milling of Bi₄Ti₃O₁₂ was carried out in a planetary ball mill with hardened-steel 13 or 6 mm diameter balls with a goal to investigate how the system responds to the constrains imposed by milling. Milling intensity for various milling parameters was derived from the electrical power measurement. The reverse amorphous ↔ crystalline phase transition induced by milling is governed by impact energy and frequency. Below a certain threshold value of impact energy crystallization does not occur, whereas a higher impact frequency accelerates amorphization. Mechanochemical reactions are predominantly discrete processes, which occur at the moment of impact.     

Determination of green,blue and yellow artificial food colorants and their abuse in herb-coloured green Easter beers on tap

Beer is one of the most popular alcoholic beverages worldwide. For consumer acceptance, significant factors are its taste, flavour and colour. This study determines selected synthetic green, blue and yellow food colorants in popular Easter herb-coloured green beers on tap produced in breweries on Holy Thursday. The abuse of beer colouring with Tartrazine (E 102), Quinoline yellow (E 104), Sunset yellow (E 110), Patent blue (E 131), Indigo carmine (E 132), Brilliant blue FCF (E 133), Green S (E 142) and Fast green FCF (E 143) was assessed in 11 green beer samples purchased in local restaurants. HPLC was used for the separation and detection of artificial colorants with diode-array detection and a Chromolith Performance CN 100 × 4.6 mm column with guard pre-column Chromolith CN 5 × 4.6 mm. Separation was performed in gradient elution with mobile phase containing methanol–aqueous 2% ammonium acetate at pH 7.0. The study showed that eight beers (70%) marketed in the Czech Republic contained artificial colorants (Tartrazine and Brilliant blue FCF). The concentration of colorants found in analysed green herb-coloured beers ranged from 1.58 to 3.49 mg l^–1 for Tartrazine, 0.45–2.18 mg l^–1 for Brilliant blue, while Indigo carmine was detected only once at concentration 2.36 mg l^–1. Only three beers showed no addition of the synthetic colorants. However, the levels of artificial colorants found in beers marketed in the Czech region were very low and did not show a serious risk for consumers’ health.     

Clarification of fruit juices by fungal pectinases

This study analyses the efficiency of fungal pectinolytic preparations produced in laboratory and commercial products used in the clarification process of apple, butia palm fruit, blueberry, and grape juices. Two crude enzymatic extracts, produced by Aspergillus niger T0005007-2 (TE1) and Aspergillus oryzae IPT 301 (TE2), were tested in solid-state and submerse cultures, respectively, in comparison to the commercial preparations Pectinex^®Clear and Pectinex^®BE Colour, used for the clarification of clear (apple, butia palm fruit) and dark (blueberry and grape) juices, respectively. With pectinases total activity at 1 U/mL of fruit juice, reactions were conducted at 30 and 50 °C, for 30 and 60 min. Time increase resulted in an improved clarification, whereas temperature increase could not be clearly linked to a greater clarification. When compared to the commercial products, the use of the crude preparation TE1 resulted in similar clarification of apple and blueberry juices. For butia palm and grape juice, however, TE1 presented the highest clarification results, revealing the potential of A. niger T0005007-2 enzymes for commercial application.