Material and Energy Interactions between Milling Bodies,Milled Particles,and Milling Environment

Changes in particle size, surface state, and composition brought about by planetary and vibration milling of silicon and quartz in various permittivity liquids were investigated. Using a variety of spectroscopic techniques (IRS, XPS, and Mössbauer spectroscopy) the changes in quality of the superficial layers of milled particles have been determined. During energy-intensive milling, the material being milled intensively interacts with the media and milling environment. The nature of the interaction and quality of the surface shell covering the milled particles depend on the reactivity and hardness of the interacting solids and of the milling environment. During planetary milling of silicon with tungsten carbide media, the superficial layers are formed by silicon suboxides and silicon oxide. The thickness of the superficial layer and the share of SiO₂ increase with increasing permittivity of liquids. Milling with steel media results in a more complicated composition of the superficial layer. According to Mössbauer spectra, the iron is present in two main forms: as a magnetically ordered form identical with basic material of balls and in a paramagnetic form as a product of a mechanically stimulated surface reaction between Si and Fe. The presence of the superficial layers on the milled particles of silicon and quartz markedly influences the values of the specific surface area. This influence should be taken into consideration when calculating the specific contamination of the milled powder.     

Reaction of N-phenylhydroxylamine in the presence of clay catalysts

The condensation reaction of N-phenylhydroxylamine in the presence of clay catalysts was studied. The main products of this reaction are azoxybenzene, aniline and nitrosobenzene. In contrast with the previously published results, p-nitrosodiphenylamine is not formed during the condensation reaction. This revised version was published online in July 2006 with corrections to the Cover Date.     

Laser ablation of Ga-Sb-Te thin films monitored with quadrupole ion trap time-of-flight mass spectrometry

Laser ablation of Ga-Sb-Te chalcogenide thin films prepared by radiofrequency magnetron co-sputtering was monitored with quadrupole ion trap time-of-flight mass spectrometry (QIT-TOF-MS). The mass spectra of 11 thin films of various compositions (Ga: 0–53.1, Sb: 0–52.0, and Te: 0–100.0 at. %) were recorded. Several series of unary (Ga_x, Sb_y, and Te_z) binary (Ga_xSb_y, Ga_xTe_z, and Sb_yTe_z), and ternary Ga_xSb_yTe_z clusters were identified in both positive and negative ion modes. Stoichiometry of observed clusters was determined. Up to 18 binary clusters (positively and negatively charged) were detected for thin film with low Sb content of 6.5 at. %. The highest number (4) of ternary clusters was observed for thin film with high Te content of 66.7 at. %. The number of generated clusters and their peaks intensity varied according to the chemical composition of thin films. Altogether, 41 clusters were detected. The laser ablation monitoring shows laser-induced fragmentation of thin film structure. The relation of clusters stoichiometries to the chemical composition of thin films is discussed. The fragmentation can be diminished by covering a surface of thin films with paraffin's, glycerol, or trehalose sugar thin layers. The stoichiometry of generated clusters shows partial structural characterization of thin films.     

Structure and Properties of the Gypsum Mortar with Silica Sand Under Temperature Load

International Journal of Thermophysics - The electrospray (ES) cooling technique, which is a combination of spray cooling and high-voltage electrostatic technology, has attracted considerable...     

Potato Tuber Dynamic Mechanical Analysis at Temperatures of Starch Gelatinization

Dynamic mechanical analysis (DMA) was applied to potato cortex tissue in temperature scans in range 30–90°C and constant air humidity of 90%. The obtained scans indicate peaks in both storage and loss module of elasticity (SM and LM, respectively) at temperatures higher than 70°C. The peaks follow starch gelatinization processes in tissue detected by DSC at lower temperatures. The peak characteristic temperatures were determined in replicated experiments for seven potato varieties. It was shown that increasing tissue density leads to higher characteristic temperatures. The peak characteristic values (for both SM and LM) were more variable and cultivar role for them was not proved. The role of the observed module peaks in the potato cooking process is discussed.     

Effect of a polyamine biosynthesis inhibitor on the quality of grape and red wine

BACKGROUND: The quality of berries and red wines is influenced by the cultivar. The aim of this study was to determine the effect of a polyamine biosynthesis (PA) inhibitor on some red grapevine cultivars with a genetically lower quality of grapes and wines. O‐Phosphoethanolamine was used as a PA inhibitor because of its positive effect on the quality of some small berries. RESULTS: The PA inhibitor at a foliar dose treatment of 7.0 g ha⁻¹ significantly increased the peroxidation inhibition of berries (1.16‐ to 1.56‐fold), the color density (from 1.66% to 69.14%) and the sensory quality of the wines with a lower genetically programmed color quality (André, Saint Laurent and Zweigeltrebe), but not the higher‐quality Alibernet variety. The PA inhibitor predominantly decreased the total phenolic and anthocyanin contents (from 37.0% to 27.5%), and it significantly decreased the contents of free polyamines in all varieties—very dramatically in Saint Laurent grapes (17.16‐ to 1.58‐fold). CONCLUSIONS: Foliar treatment of red grapevine varieties of a low quality, using O‐phosphoethanolamine, can help produce higher‐quality wines. Copyright © 2011 Society of Chemical Industry