Sonochemical Activation of Al/Ni Hydrogenation Catalyst

This paper proposes a sonochemical approach to the nanostructuring of Al/Ni catalyst with high content of accessible Ni centers and a high reusability. The surface and bulk composition as well as pore size distribution of this catalyst are controlled synergistically by adjusting the ultrasound intensity in aqueous solution. Sonochemical activation of Al/Ni alloy leads to formation of mesoporous Al/Ni metallic based frameworks with surface area up to 125 m² g^?1, and regular distribution of nickel active center in the porous matrix. One of the opportunities of porous Al/Ni catalyst is that due to a time‐resolved controllable formation of protective oxide layer it can be stored and handled under air in comparison to traditional Raney catalysts which need inert conditions. The Al/Ni catalyst is characterized by scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), confocal scanning fluorescence microscopy (CSFM), solid‐state NMR experiments, and powder X‐ray diffraction analysis (PXRD). The catalytic activity was investigated for the hydrogenation of acetophenone.     

The effects of handedness and reachability on perceived distance.

Previous research has suggested that perceived distances are scaled by the action capabilities of the body. The present studies showed that when “reachability” is constrained due to a difficult grasp required to pick up an object, perceived distance to the object increases. Participants estimated the distances to tools with handle orientations that made them either easy or difficult to grasp with their dominant and nondominant hands. Right-handed participants perceived tools that were more difficult to grasp to be farther away than tools that were easier to grasp. However, perceived distance did not differ in left-handed participants. These studies suggest that, when reaching toward a target, the distance to that target is scaled in terms of how far one can effectively reach, given the type of reaching posture that is executed. Furthermore, this effect is modulated by handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

同时提取大豆中的油脂和蛋白质的工艺

近几年来 ,国外油脂科技的发展非常迅速 ,特别是在油脂工程的大型化、规模化 ,以及油脂工厂自动控制方面发展尤为迅速 ,同时 ,在油脂、油料蛋白及其功能性的研究方面也取得了不少重要成果。应广大读者的要求 ,《中国油脂》杂志从本期开始增加“国外动态”栏目 ,以期让广大读者了解更多国外新技术的动态。本期我刊选编了由国家粮食储备局西安油脂科学研究设计院武丽荣工程师根据“2 0 0 2年北京国际大豆技术及开发合作研讨会暨展示会 (CISCE2 0 0 2 )”的论文编译了几则有关油脂加工方面的论文 (摘编 ) ,这些论文从不同侧面反映了国外油脂行业的一种信息 ,以促进我国油脂工业的发展 ,进而促进我国油脂行业的科技进步     

SIMULATION OF THE PROCESS STABILITY OF HPC MILLING OPERATIONS

The optimisation of high-performance cutting (HPC) processes under technological and economical aspects often proves to be extremely difficult due to the appearance of process instabilities, so-called “chatter”. The identification of ideal process parameters often involves the systematic testing with varied cutting parameters. Simulation of the process stability offers a less costly way of optimising processes prior to production. However, the predictions for the stability of high performance milling processes exhibit great deviation from experimental results. The objective is to analyse and to prevent errors within the simulation methods to make stability simulation a reliable tool in process planning. In order to improve the quality of stability simulation, the interacting Systems “Machine Tool” and “Cutting Process” are analysed individually. Methods for the coupled simulation of both systems are implemented to identify stable working conditions. As a result of this work, a time domain simulation environment for the investigation of high performance milling operations is presented. It considers the complex behaviour of the cutting process as well as the speed dependent machine tool dynamics. Cutting tests have been conducted to verify the benefit of the enhanced simulation method.     

Diagenetic transformation of dissolved organic nitrogen compounds under contrasting sedimentary redox conditions in the Black Sea

Remineralization of organic matter in reactive marine sediments releases nutrients and dissolved organic matter (DOM) into the ocean. Here we focused on the molecular-level characterization of DOM by high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in sediment pore waters and bottom waters from contrasting redox regimes in the northern Black Sea with particular emphasis on nitrogen-bearing compounds to derive an improved understanding of the molecular transformations involved in nitrogen release. The number of nitrogen-bearing molecules is generally higher in pore waters than in bottom waters. This suggests intensified degradation of nitrogen-bearing precursor molecules such as proteins in anoxic sediments: No significant difference was observed between sediments deposited under oxic vs anoxic conditions (average O/C ratios of 0.55) suggesting that the different organic matter quality induced by contrasting redox conditions does not impact protein diagenesis in the subseafloor. Compounds in the pore waters were on average larger, less oxygenated, and had a higher number of unsaturations. Applying a mathematical model, we could show that the assemblages of nitrogen-bearing molecular formulas are potential products of proteinaceous material that was transformed by the following reactions: (a) hydrolysis and deamination, both reducing the molecular size and nitrogen content of the products and intermediates; (b) oxidation and hydration of the intermediates; and (c) methylation and dehydration.     

Design and demonstration of an experimental membrane reactor set-up for oxidative coupling of methane

In this experimental research, the performance of the oxidative coupling of methane (OCM) reactions in a porous packed bed membrane reactor was investigated. A commercially available porous alpha-alumina membrane was modified to obtain the characteristics needed for a stable and catalytically inert OCM membrane reactor. The silica-sol impregnation–calcination method and a new silicon oxycarbide (SiOC) coating-calcination approach were applied to modify the membrane. The characteristics of the resulted membrane and its typical performance as OCM membrane reactor are reported.     

Horizontal reactive distillation for multicomponent chiral resolution

A novel horizontal reactive distillation apparatus and a new overall process scheme are proposed for continuous multicomponent chiral resolution via reversible enantioselective acylation of a chiral (racemic) substrate by a chiral (racemic) acyl donor. The process enables simultaneous production of up to four enantiomers with enhanced chiral purity. Kinetic studies, miniplant experiments, and process simulation results are described for a model lipase‐catalyzed reaction: (R)‐enantioselective transesterification of (R,S)‐1‐n‐butoxy‐2‐propanol with (R,S)‐1‐methoxy‐2‐acetoxypropane to produce (R)‐1‐n‐butoxy‐2‐acetoxypropane, (R)‐1‐methoxy‐2‐propanol, and the two unreacted (S)‐enantiomers of the (R,S)‐reagents. A horizontal, compartmentalized reactive distillation vessel is specified instead of a conventional reactive distillation column to provide longer liquid‐phase residence time needed for adequate conversion. Low vapor‐traffic pressure drop allows operation under vacuum at reduced temperatures for good enzyme stability and enantioselectivity. The general technology has potential as a means to producing a wide range of chiral synthons used in asymmetric syntheses of chiral pharmaceuticals and other biologically active products. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2603–2620, 2013