Synthesis of palladium nanoparticles using a continuous flow polymeric micro reactor

A continuous flow polymeric micro reactor, fabricated using a negative photo resist SU-8 on a 10 x 10 cm PEEK (polyetheretherketone) substrate by standard UV lithography, was utilized to synthesize palladium nanoparticles. The nanoparticles were characterized by Transmission Electron Microscopy, Selected Area Electron Diffraction and X-ray Diffraction. The Pd nanoparticles synthesized in the micro reactor were found to have a narrower size distribution when compared with those obtained by the conventional batch process.     

Fast branch & bound algorithms for optimal feature selection

A novel search principle for optimal feature subset selection using the Branch & Bound method is introduced. Thanks to a simple mechanism for predicting criterion values, a considerable amount of time can be saved by avoiding many slow criterion evaluations. We propose two implementations of the proposed prediction mechanism that are suitable for use with nonrecursive and recursive criterion forms, respectively. Both algorithms find the optimum usually several times faster than any other known Branch & Bound algorithm. As the algorithm computational efficiency is crucial, due to the exponential nature of the search problem, we also investigate other factors that affect the search performance of all Branch & Bound algorithms. Using a set of synthetic criteria, we show that the speed of the Branch & Bound algorithms strongly depends on the diversity among features, feature stability with respect to different subsets, and criterion function dependence on feature set size. We identify the scenarios where the search is accelerated the most dramatically (finish in linear time), as well as the worst conditions. We verify our conclusions experimentally on three real data sets using traditional probabilistic distance criteria.     

Subtle but distinct impairments of rats with chemical lesions in the thalamic mediodorsal nucleus, tested in a radial arm maze.

Tested the performance of 18 hybrid BD9?×?BD10 rats trained in a radial arm maze before and after chemical lesions of the thalamic mediodorsal nucleus or the ventral tegmental area. Their behavior was compared with that of 18 sham-operated controls. Lesions were produced with ibotenic acid, a compound that selectively destroys neurons while apparently leaving fibers of passage intact. Results revealed no intergroup differences in the number of errors performed when all 6 trials were given in 1 session without interruption. The group with mediodorsal lesions, however, made significantly more errors than either of the other 2 groups when a delay of 1 hr was interposed between the 1st 4 and the last 2 trials. Furthermore, these Ss differed from Ss of the other groups in the number of sessions necessary to reach criterion, in the time needed to finish a session, and in the directness with which a goal was approached. Ss with lesions of the ventral tegmental area did not differ from Ss of the sham-operated control group in any of the measures taken. It is suggested that the deficits of rats with mediodorsal lesions resemble qualitatively those found in human patients with lesions of the mediodorsal nucleus. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Zum überflutungsverhalten zwei- und dreiphasig betriebener Rührreaktoren

The flooding behaviour of two- and three-phase operating stirred reactors . The present state of research concerning the flooding behaviour of aerated fluids and suspensions is presented. The author's own investigations, undertaken partly on a semi-technical scale (tank diameter D = 1.5 m) show the most important parameters of this undesirable aerated state during the operation of stirred reactors. For a given stirrer speed the superficial gas velocity, the tank size, and the fluid viscosity are important. Solid particles sediment out when flooding is reached. An objective measuring method for determining the occurrence of flooding was adopted.     

Study of structure and properties of ZnO–Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>–P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Glasses of the ternary system ZnO–Bi₂O₃–P₂O₅ were prepared and studied in two compositional series 50ZnO–xBi₂O₃–(50 − x)P₂O₅ and (50 − y)ZnO–yBi₂O₃–50P₂O₅. Two distinct glass-forming regions were found in the 50ZnO–xBi₂O₃–(50 − x)P₂O₅ glass series with x = 0–10 and 20–35 mol.% Bi₂O₃. All prepared Bi₂O₃-containing glasses reveal a high chemical durability. Small additions of Bi₂O₃ (∼5 mol.%) improve thermal stability of glasses. All glasses crystallize on heating within the temperature range of 505–583 °C. Structural studies by Raman and ³¹P MAS NMR spectroscopies showed the rapid depolymerisation of phosphate chains within the first region with x = 0–15 and the presence of isolated Q⁰ phosphate units within the second region with x = 20–35. Raman studies showed that bismuth is incorporated in the glass structure in BiO₆ units and their vibrational bands were observed within the spectral region of 350–700 cm⁻¹. The evolution of properties and the spectroscopic data are both in accordance with a network former effect of Bi₂O₃.     

Towards an optimised lab procedure for long-term oxidative ageing of asphalt mix specimen

Ageing of bitumen leads to increased stiffness and brittleness. Thus, bituminous bound pavements become more prone to failure by low-temperature and fatigue cracking. Therefore, the ageing behaviour of bitumen has a crucial impact on durability, as well as recyclability of pavements. To assess ageing of bitumen, the rolling thin film oven test and pressure ageing vessel are standardised methods for short-term and long-term ageing in the lab. For lab-ageing of hot mix asphalt (HMA), various methods have been developed in the last decades. This paper presents a study on the potential of employing a highly oxidant gas for simulating the long-term oxidative ageing of asphalt mix specimens in the lab. Based on the results, an optimised lab-ageing procedure (Viennese Ageing Procedure – VAPro) for compacted HMA specimens to assess mix performance of long-term lab-aged specimens is developed. Thus, it is possible to optimise mix design not only for short-term performance but to take into account effects of oxidative ageing during its in-service life. VAPro is based on a triaxial cell with forced flow of a gaseous oxidant agent through the specimen. The oxidant agent is enriched in ozone and nitric oxides to increase the rate of oxidation. It is shown by stiffness tests of unaged and lab-aged specimens, as well as by Dynamic Shear Rheometer tests of recovered binder from aged specimens that asphalt mixes can be long-term aged at moderate temperatures (+60°C) and within 4 days and a flow rate of 1 l/min by applying VAPro. Thus, an ageing procedure is at hand that can simulate long-term ageing at conditions that are representative of conditions that occur in the field within an efficient amount of time.     

ATP and Presentation Service for Mizar Formalizations

This paper describes the Automated Reasoning for Mizar ( $\textsf{Miz}\mathbb{AR}$ ) service, which integrates several automated reasoning, artificial intelligence, and presentation tools with Mizar and its authoring environment. The service provides ATP assistance to Mizar authors in finding and explaining proofs, and offers generation of Mizar problems as challenges to ATP systems. The service is based on a sound translation from the Mizar language to that of first-order ATP systems, and relies on the recent progress in application of ATP systems in large theories containing tens of thousands of available facts. We present the main features of $\textsf{Miz}\mathbb{AR}$ services, followed by an account of initial experiments in finding proofs with the ATP assistance. Our initial experience indicates that the tool offers substantial help in exploring the Mizar library and in preparing new Mizar articles.     

Die Strom- und Momentverhältnisse der untersynchronen Bremsschaltung von Siemens

Ohne ZusammenfassungSiemens-Z. 1929 S. 565.