Triggering steam explosions of single drops of a molten ferrosilicon alloy with a simple encapsulated mechanical impactor

We have developed a simple and inexpensive encapsulated mechanical impactor that can be operated under water. The unit reproducibly generates upward-directed pressure transients in the water with peaks of approximately 0.13 MPa measured 100 mm above its surface. These pulses have been used to trigger steam explosions of drops of a molten ferrosilicon alloy when they are either just above the unit in free fall through the water or shortly after they land on its surface. The impactor is study, reliable, safe, and environmentally neutral and resets for reuse within seconds. Compared to other triggering techniques, the impactor does not generate light, bubbles, or strong water motion that obscure or appreciably affect the initiation or early stages of the steam explosions. This permits good imaging and measurements at essentially all times during the triggering and subsequent development of the explosions.     

Electric power distribution and environment: interference of power installation magnetic fields on computer systems

The present study analyzes the electromagnetic interference produced on visual display units (VDUs) in domestic and industrial environments. The main sources of disturbance may be identified in three-phase lines, unbalanced currents, currents in earthing systems, proximity of power installations, proximity of railway tracks, and presence of harmonics on the neutral conductor. Magnetic-field interference for PCs is practically limited to the deflection of the cathode-ray tube (CRT) electron beam. The vertical magnetic field determines a horizontal electron beam motion. The distortion depends linearly on magnetic field intensity and on the difference between the frequency of the CRT vertical raster scan and the frequency of the interfering magnetic field. Herein are analyzed two actual cases of interference produced by the DC-supply line of a metropolitan tram network and by the public electric power distribution network.     

Estimation of dietary intake of pesticide residues by the Italian population during 1997

In 1997 the Italian monitoring programme for pesticide residues in food comprised 7951 samples of 152 different foods for which a total of 275 pesticides were analysed. For 90 pesticides, the National Estimated Daily Intakes (NEDIs) were calculated by using the 90th percentile value and the food consumption data for the general Italian population. The calculated NEDIs were found to represent only a small portion of the respective Acceptable Daily Intake (ADI).     

Age differences and the identity negative priming effect: An updated meta-analysis.

A recent meta-analysis (P. Verbaeghen & L. De Meersman, 1998a) revealed that older adults show a reliable but significantly reduced negative priming effect compared with young adults. The present study provides an updated quantitative review on the effect of aging on the magnitude of the negative priming effect in identity tasks. This analysis demonstrated that the negative priming effect was not significantly different between young and old adults. This result differs from P. Verhaeghen and L. De Meersman's study. The implications of this finding for inhibitory-based theories of cognitive aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increase of trans-resveratrol in typical Sicilian wine using β-Glucosidase from various sources

β-Glucosidase (EC 3.2.1.21) (β-G) from different sources were tested to increase the trans-resveratrol in some Sicilian wines by hydrolysing resveratrol glucoside. β-G from Aspergillus niger mould was tested as a crude and purified enzyme, and compared with the same enzyme from Saccharomyces cerevisiae yeast. Specific purification served to eliminate collateral enzyme activities so that β-G could be used simply and economically. Aspergillus niger β-G produced trans-resveratrol increases of up to 75%, with no change in physico-chemical properties and bouquet, and an increase in health and nutritional properties. S. cerevisiae β-G raised free-terpenol levels, but impaired wine colour due to anthocyanase activity.     

Silica and Magnesia Dopant Distributions in Alumina by High-Resolution Scanning Secondary Ion Mass Spectrometry

Trace SiO₂ and MgO additive distributions in sintered alumina have been studied using high-resolution scanning secondary ion mass spectrometry (SIMS). When doped with each additive individually, evidence is seen for both strong silicon segregation to grain boundaries ( C _gb/ C _grain similar/congruent 300) in SiO₂-doped alumina and strong magnesium segregation to grain boundaries ( C _gb/ C _grain similar/congruent 400) in MgO-doped alumina. When codoped with both SiO₂ and MgO, segregation of both ions to grain boundaries is reduced by a factor of 5 or more over single doping. The additive concentrations increase proportionally in the grains, and both dopants become more uniformly distributed throughout the bulk. It is concluded that codoping with these additives increases their mutual bulk solid solubility and decreases their interfacial segregation over single doping. The beneficial effect of MgO additions in controlling microstructure development in alumina and improving corrosion resistance to aqueous HF stems from its ability to redistribute silicon ions from grain boundaries into the bulk.     

用于三电平逆变器的IGBT提高DC／AC转换的效率

当我们谈论效率时，我们主要指的是电力效率。然而，这种用法并不是效率一次本身的完整含义。在电力电子应用巾，工程师在开发新产品过程中的追求的主要目标是以最大限度地发挥不同类型的效率，如电效率和热效率，以及优化谐波失真和产品整体的尺寸。     

Testing and numerical simulation of a medium strength rock material under unconfined compression loading

This study aims to numerically and experimentally investigate the response of a medium strength rock material under unconfined compression loading up to failure. The unconfined compressive strength (UCS) is one of the most important parameters in characterising rock material behaviour. Hence the UCS is crucial in understanding the failure mechanism of fractured rocks. An effective approach to determine the UCS and to investigate the behaviours of rock materials under unconfined compression is essential in the majority of research fields of rock mechanics. The experimental configuration for the unconfined compression test, suggested by the protocols of the ASTM standard, has some limitations which affect the accuracy in determination of the real UCS. Among several alternative configurations proposed, the Mogi's configuration seems to be the most appropriate one. Therefore, the ASTM and Mogi's configurations were used to perform the tests on a medium strength rock material, i.e. Pietra Serena sandstone. The results using two configurations were discussed in terms of the differences. The tests were also replicated in LS-DYNA using a finite element method (FEM) coupled smooth particle hydrodynamics (SPH) technique. This technique is employed in this study due to its capabilities to cope with large deformation issues related to the rocks. An advanced material model, called the Karagozian and Case Concrete (KCC) model, is implemented in the numerical simulations. The KCC model consists of three independent fixed failure surfaces and it can consider the damage accumulation based on the current state of stress among these failure surfaces. An equation-of-state (EOS) is used in conjunction with KCC material model for decoupling the volumetric and deviatoric responses. The numerical and experimental results were finally compared with the focus on the stress–strain diagram and the failure patterns. The comparison shows that the numerical results are in good agreement with the experimental results.     

Catalysts for the Ethoxylation of Esters

The intermediates for the production of nonionic surfactants can be derived from petrochemicals and/or from renewable raw materials. In both, the role of catalysis is fundamental. In this paper the main results reported in the literature related with the catalysis for ethoxylation of fatty esters will be reviewed. The main open challenges for these technologies will be outlined.     

Copper(I/II), α/β‐Synuclein and Amyloid‐β: Menage à Trois?

Copper binding to α‐synuclein (aS) and to amyloid‐β (Ab) has been connected to Parkinson's and Alzheimer's disease (AD), respectively, because Cu ions can modulate the peptide aggregation, and these Cu ? peptide complexes can catalyse the production of reactive oxygen species (ROS). In a significant proportion of AD brains, aggregation of aS and Ab has been detected, and it was proposed that Ab and aS interact with each other. Thus, we investigated the potential interactions of Ab and aS through their binding of copper(I) and copper(II). Additionally, β‐synuclein (bS) was investigated, due to its additional methionine residue, a potential Cu^I ligand. We found that: 1) the peptides containing the Cu‐binding domains Ab1–16, aS1–15 and bS1–15 have similar affinities towards Cu^II and towards Cu^I, with Ab1–16 being slightly stronger, 2) in the case of Cu^I, the additional Met residue in bS1–15 increased the affinity slightly, 3) the exchange of Cu^I/II between the two peptides is rapid (≤ms), 4) a/bS1–15 and Ab1–16 form a heterodimeric complex with Cu^II, 5) Cu^I probably promotes a transient ternary complex, 6) the different Cu^I/II coordination of Ab1–16, aS1–15 and bS1–15 impacts the capacity to produce ROS and to oxidise catechol, and 7) when Ab1–16, aS1–15 and Cu are present, the ROS production more closely resembles that by Ab1–16. The work gives insights into the coordination chemistry of these related peptides, and the relevance of coordination differences, the ternary complex and ROS production are discussed.