Comparison of the GFFF and LALLS Methods for the Measurement of Starch Granule Size Distribution in Spring Barley Caryopses

A newly developed method GFFF (Gravitational Field‐Flow Fractionation) and the well known method LALLS (Low Angle Laser Light Scattering) were used to assess starch granule size distribution of ten varieties of spring barley. As a distribution criterion, the ratio of starch granule content larger than 8 μm (type A) and smaller than 8 μm (type B) was chosen. Both methods divided the observed set in a similar way. Varieties Akcent, Forum and Atribut formed a variety set with the highest ratio of large and small starch granules. Varieties Scarlet and Kompakt had intermediate ratios. The remaining five varieties Amulet, Novum, Olbram, Tolar and Krona had the lowest ratios of large and small starch granules. Statistical analysis showed that there was a highly significant correlation between the GFFF and LALLS methods.     

Untersuchungen zur Kinetik und zum Wärmeeffekt der Cyclotrimerisierung von Arylcyanaten

Studies on the Kinetics and the Reaction Heat of the Cyclotrimerization of Aryl Cyanates The kinetics and the reaction enthalpy of the polycyclotrimerization of 2,2-bis(4-cyanatophenyl)propane in ditolylmethane solution were investigated by means of direct calorimetry, varying the concentration of the catalyst (chromium(III) acetyl acetonate) and of the monomer as well as the reaction temperature, the water content of the solvent, and the amount of added acetyl acetone. The maximum reaction rate is proportional to the monomer concentration, to the square root of the concentration of the catalyst, and to the water content. It is inversely proportional to the amount of water added. Presumably, water participates in the formation of the active species of the catalyst, and the autocatalytic nature of the polycyclotrimerization of 2,2-bis(4-cyanatophenyl)propane in presence of chromium acetylacetonate is due to accumulation of the latter during reaction.     

Suitability of some selected maize hybrids from Serbia for the production of bioethanol and dried distillers' grains with solubles

BACKGROUND: Bioethanol is mostly produced from starchy parts of the corn grain kernel leaving significant amounts of valuable by‐products such as dried distillers' grains with solubles (DDGS) which can be used as a substitute for traditional feedstuff. The suitability of six maize hybrids from Serbia was investigated for bioethanol and DDGS production. The correlation between physical and chemical characteristics of the grain, bioethanol yield and quality of the corresponding DDGS was assessed. RESULTS: All hybrids had very different chemical composition and physical characteristics which could allow various applications. The highest bioethanol yield (94.5% of theoretical) and volumetric productivity (2.01 g l^?1 h^?1) were obtained with hybrid ZP 434 and the lowest with ZP 611k. Regarding chemical composition, all DDGS samples manifested good properties as feed components. Their protein content was higher compared to the kernel. In addition, the samples showed high digestibility and high mineral content, especially of calcium and phosphorus. CONCLUSION: A hybrid ZP 434 was selected as the most promising bioethanol producer. This property is attributed to the highest level of soft endosperm which is more susceptible to starch‐hydrolysing enzymes. A high yield potential per hectare makes it the best candidate for commercial bioethanol production. © 2012 Society of Chemical Industry     

Tropfenbildung beim Elektro-Schlacke-Umschmelzverfahren

Beschreibung der Versuchsmethode zur direkten Messung der Tropfenfrequenz des abtropfenden Metalles beim Elektro-Schlacke-Umschmelzverfahren. Ermittlung von Korrelationen zwischen Tropfenfrequenz und technologischen Parametern wie Abschmelzgeschwindigkeit und Erstarrungsgeschwindigkeit beim Umschmelzen von hochlegierten Stahlsorten. Behandlung der Kinetik der Tropfenbildung während des Umschmelzens. Einfluß von Zugaben in die Schlacke (AI, Ti) auf die Geschwindigkeit der Tropfenbildung bei niedrig- und hochlegierten Stählen. Erörterung des Zusammenhangs zwischen Tropfenfrequenz und der Geometrie des Metallsumpfes.     

Vergleich verschiedener Verfahren zur Ermittlung der Nachgiebigkeit hydraulischer Zugprüfmaschinen

Beschreibung des Vorgehens bei der Ermittlung der Nachgiebigkeit hydraulischer Zugprüfmaschinen aus der Periodendauer der Eigenschwingungen des Pendelmanometers, aus dem Kraft-Verlängerung-Schaubild im Bereich des Kraftabfalls nach Erreichen der oberen Streckgrenze, aus den gleichzeitig aufgenommenen Kraft-Verlängerung-und Kraft-Zeit-Schaubildern, aus dem Kraft-Verlängerung-Schaubild mit Zeitmarken sowie aus den gleichzeitig aufgenommenen Kraft-Verlängerung- und Verlängerung-Zeit-Schaubildern. Vergleich der mit verschiedenen Verfahren ermittelten Werte der Nachgiebigkeit einer 100-kN-Prüfmaschine für unterschiedliche Probenformen und in verschiedenen Kraftmeßbereichen.     

Characteristics of Zinc Corrosion and Formation of Conversion Films on the Zinc Surface in Acidic Solutions of Cr(III) Compounds

The influence of the components of an acidic solution: Cr(III) nitrate-malonic acid-Co(II) salt and treatment conditions on zinc dissolution and formation of Chromate films as well as on their decorative and protective properties have been studied using the analytical, XPS, structural and accelerated corrosion test methods. An organic acid is the main component, which has an essential influence on zinc dissolution and formation of Chromate films as well as their decorative and protective properties. The influence of organic acid is directly related with the state of the Cr³⁺ ions in chromating solution. When the Cr³⁺ ions are in the form of hexaaquaions, the organic acid increases the quantities of the zinc dissolved and the Cr(III) deposited on the zinc surface (especially at 60°C). It also predetermines the formation of a thick, porous Chromate film with large cracks at 60°C. Its decorative and protective properties are rather poor. When Cr³⁺ ions are in the form of a complex with organic acid, the quantities of the zinc dissolved and the Cr(III) deposited on the zinc surface significantly decrease and thinner Chromate films with an even surface, good decorative appearance and high corrosion resistance are formed Decorative blue-bright Cr(VI)-free films with a slight iridescent tint, obtained in solution, containing Cr(III) nitrate (0.2), malonic acid (0.3) and Co(II) nitrate (0.02) mol dm^?3, at p H 1.6-2.0 at room temperature over 30–60 s, possess corrosion resistance (192–240 h in a salt spray chamber) similar to that of iridescent Chromate films, obtained in acidic Cr(VI) solution.     

Kinetics of structural relaxation in glasses: A hierarchical model of relaxation centers

A definition is proposed for the characteristic time of structural relaxation τ_{str. rel} in metallic glasses—the universal parameter describing the kinetics of various processes associated with the structural relaxation. The behavior of τ_{str. rel} in model situations of isothermal annealing of a glass and its heating at a constant rate is considered. In the former case, the time τ_{str. rel} is equal to the age of the sample. In the latter case, after a time, τ_{str. rel} reaches a steady-state value. This is in agreement with the τ_{str. rel} values determined from the creep rate. The kinetics of structural relaxation is analyzed with due regard for the hierarchical structure of the phase space in glasses. The kinetic equation taking into account this feature is proposed, and the results of its numerical solution are given.     

Production of articles and powders based on stabilized zirconium dioxide

The Chepetskii Mechanical Works produces articles and powders based on ZrO₂ stabilized by Y₂O₃ (fully or partly) and CaO. The production volume is up to 1 ton per year. __________ Translated from Novye Ogneupory, No. 6, pp. 55–56, June, 2007.     

Thermodynamic conditions for inclusions modification in calcium treated steel

The presented paper discussed the fundamental or common thermodynamical relations between calcium-treated aluminium-killed molten steel and non-metallic inclusions. The phase and chemical analyses of inclusions have proven that the correctness of calcium addition can be confirmed and that the analysis of those phenomena can show the effects of previous calcium treatment of aluminium-killed steel. To make the process of manufacturing quality steel successful the factor affecting the necessary calcium addition should be taken into consideration already during the process. Steel, containing too much calcium could have CaS inclusions with a high melting point, while too low contents of calcium cause unsatisfactory modification of solid alumina inclusions to complex liquid calcium-aluminate inclusions. This research included the examination of thermodynamic relations in calcium addition and its reactions with solid Al₂O₃ inclusions. A detailed analysis of the CaO–Al₂O₃ binary system established the modification of solid alumina inclusions via the following intermediate phases: CaO · 6Al₂O₃, CaO · 2Al₂O₃, CaO · Al₂O₃ and liquid phase 12CaO · 7Al₂O₃ and finally again solid CaO, at 1873 K (1600°C). The investigation discusses the further research engaged in consideration of CaO- and Al₂O₃-activities change in each of the quoted intermediate phases. The system as a whole includes details of oxygen activities.