Model oxide-supported metal catalysts: energetics,particle thicknesses,chemisorption and catalytic properties

Many industrially important catalysts consist of late transition metal particles supported on the surfaces of oxide materials. Our studies of such systems using model catalysts consisting of metal films vapor deposited onto the surfaces of single-crystalline oxides are reviewed here. Systems studied include Cu on ZnO, Pt on ZnO, Au on TiO₂ and Cu, Ag and Pb on MgO. A unique adsorption microcalorimeter was developed to measure directly the energetic stability of the metal atoms on the oxide surfaces and the adhesion energy at the metal/oxide interface, which clarify the structural and chemisorption properties of the ultrathin metal particles. The structure of the oxide surface and the metal particles was elucidated by low-energy electron diffraction (LEED), low-energy ion scattering spectroscopy (ISS), angular-resolved X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD). The electronic character of the metal particles was revealed by XPS, Auger electron spectroscopy (AES), band-bending and work function measurements. Sintering rates were measured by temperature-programmed ion scattering spectroscopy (TPISS). The chemisorption properties of these particles and their catalytic reactivity were monitored by mass spectroscopy and temperature-programmed desorption (TPD).     

Novel aromatic macrocyclic oligomers: intermediates for the preparation of high-performance polymers

Recent studies aimed at the development of macrocyclic oligomers as the intermediates for the preparation of high-performance polymers are reviewed. Efficient methods for the preparation of a range of cyclic oligomers, such as aryl ether ketones, aryl ether phthalazines, aryl ether isoquinolines, aryl ether phthalazinones, and arylene sulfides, have been developed. Cyclization was achieved via a nucleophilic aromatic substitution reaction under high-dilution conditions. The cyclic aryl ether oligomers undergo a facile ring-opening polymerization to form high molecular weight polymer. Cyclic oligomers containing an aromatic sulfide linkage also undergo a facile free-radical ring-opening polymerization to form high molecular weight polymers which can be amorphous or crystalline. Due to their low molecular weights, these cyclic oligomers have very low melt viscosities which makes them attractive intermediates for a variety of applications for which the conventionally prepared high molecular weight polymers would not be suitable.     

The wabush mines fire

How could a five-million-dollar fire occur in a seemingly low hazard industry? The author discusses one such fire and examines the lessons learned from it. It takes careful study to determine if well-known fire protection principles are being violated.     

Partial Transient Liquid-Phase Bonding, Part II: A Filtering Routine for Determining All Possible Interlayer Combinations

Partial transient liquid-phase (PTLP) bonding is currently an esoteric joining process with limited applications. However, it has preferable advantages compared with typical joining techniques and is the best joining technique for certain applications. Specifically, it can bond hard-to-join materials as well as dissimilar material types, and bonding is performed at comparatively low temperatures. Part of the difficulty in applying PTLP bonding is finding suitable interlayer combinations (ICs). A novel interlayer selection procedure has been developed to facilitate the identification of ICs that will create successful PTLP bonds and is explained in a companion article. An integral part of the selection procedure is a filtering routine that identifies all possible ICs for a given application. This routine utilizes a set of customizable parameters that are based on key characteristics of PTLP bonding. These parameters include important design considerations such as bonding temperature, target remelting temperature, bond solid type, and interlayer thicknesses. The output from this routine provides a detailed view of each candidate IC along with a broad view of the entire candidate set, greatly facilitating the selection of ideal ICs. This routine provides a new perspective on the PTLP bonding process. In addition, the use of this routine, by way of the accompanying selection procedure, will expand PTLP bonding as a viable joining process.     

钢铁、钛和铝工业废渣在去除水中重金属和酸性中的作用

选取钢铁工业废渣中的钒钛磁铁矿选铁尾矿渣、钒钛磁铁矿含钛高炉渣、普通高炉渣、钢渣,钛工业废渣中的钒钛磁铁矿选钛尾矿渣和铝工业废渣中的赤泥作为研究对象,通过圆柱试验以检验其对水中重金属Cd2＋、Co2＋、Cu2＋、Mn2＋、Ni2＋、Zn2＋和酸性的去除能力。这6种工业废渣对水中的Cd2＋的吸附容量为278~6 811 mg/kg,对Co2＋的吸附容量为127~6 052 mg/kg,对Cu2＋的吸附容量为442~53 566 mg/kg,对Mn2＋的吸附容量为95~5 594 mg/kg,对Ni2＋的吸附容量为158~6 213 mg/kg,对Zn2＋的吸附容量为151~6 710 mg/kg,对酸的中和容量为4.5~8.9 mol H＋/kg。工业废渣尤其是钢渣和赤泥在改善地下水酸性和去除矿业或工业废水中的重金属离子和酸性方面具有很好的应用前景,可以达到以废治废的目的。     

Mundane aesthetics.

With the publication of Zür experimentalen ?sthetik (1871) and Vorschule der ?sthetik (1876), Fechner laid the foundations for a new field termed experimental aesthetics, and provided three methods for empirical research. Of these, the method of choice has dominated subsequent research. It is argued that this method, in combination with a narrow, post-Baumgarten definition of aesthetics as pertaining mainly to the experience of art, has not served aesthetics well. In so doing it has overlooked the vast corpus of everyday objects for which people engage in aesthetic choice. Termed mundane aesthetics, this represents the low end, design, as distinct from the high end, art. The aesthetics of the mundane represents everyday reality, far removed from the rarefied pursuit of art. A study is reported into that most mundane and ubiquitous activity, selecting a paint color for the home. It eschews the laboratory and, instead, uses a retrospective method supported by qualitative data analysis (NVivo). The results indicate that aesthetic choice involves processes that are far from uniform, far from instantaneous (cf. laboratory studies), and that employ both internal and external aids reflecting cognitive, emotional, and social considerations. Selecting a wall color emerges as a surprisingly sophisticated process and, on the basis of the present study, one that women appear better equipped to perform than men. A parallel is drawn with the domain of decision research, particularly naturalistic decision-making. Mundane aesthetics involves a decision process, and not simply an affective choice. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Atomic force microscopy as a nanoscience tool in rational food design

Atomic force microscopy (AFM) is a nanoscience tool that has been used to provide new information on the molecular structure of food materials. As an imaging tool it has led to solutions to previously intractable problems in food science. This type of information can provide a basis for tailoring food structures to optimise functional behaviour. Such an approach will be illustrated by indicating how a basic understanding of the role of interfacial stability in complex foods systems can be extended to understand how such interfacial structures behave on digestion, and how this in turn suggests routes for the rational design of processed food structures to modify lipolysis and control fat intake. As a force transducer AFM can be used to probe interactions between food structures such as emulsion droplets at the colloidal level. This use of force spectroscopy will be illustrated through showing how it allows the effect of the structural modification of interfacial structures on colloidal interactions to be probed in model emulsion systems. Direct studies on interactions between colliding soft, deformable droplets reveal new types of interactions unique to deformable particles that can be exploited to manipulate the behaviour of processed or natural emulsion structures involved in digestion processes. Force spectroscopy can be adapted to probe specific intermolecular interactions, and this application of the technique will be illustrated through its use to test molecular hypotheses for the bioactivity of modified pectin molecules. Copyright © 2011 Society of Chemical Industry     

The mountain bike — the dream machine?

This paper examines the development of recreation on mountain bikes, since they were introduced in 1983. It considers some of the social conflicts that have reportedly arisen and then presents the results of a user survey undertaken in 1992. This provides a profile of mountain bike use and users. The aim of the study is to provide landscape managers, planners etc., with basic information about this latest form of countryside recreation so as to encourage more effective provision and management.