Dressing of grinding wheels for high rate of metal removal

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY WITH PRIOR ARRANGEMENT

Semi-permanant grinding wheels for internal grinding operations

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

The removal of temporary organic binder from vitreous silicon carbide grinding wheels during firing

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

The Effect of low-grade aggregates on the abrasion resistance of concrete

Three types of crushed rock aggregate were appraised, these being Carboniferous Sandstone, Magnesian Limestone and Jurassic Limestone. A comprehensive aggregate testing programme assessed the properties of these materials. Two series of specimen slabs were cast and power finished using recognised site procedures to assess firstly the influence of these aggregates as the coarse fraction, and secondly as the fine fraction. Each specimen slab was tested at 28 days under three regimes to simulate 2-body abrasion, 3-body abrasion and the effect of water on the abrasion of concrete. The abrasion resistance was measured using a recognised accelerated abrasion testing apparatus employing rotating steel wheels. Relationships between the aggregate and concrete properties and the abrasion resistance have been developed with the following properties being particularly important - Los Angeles Abrasion and grading of the coarse aggregate, hardness of the fine aggregate and water-cement ratio of the concrete. The sole use of cube strength as a measure of abrasion resistance has been shown to be unreliable by this work. A graphical method for predicting the potential abrasion resistance of concrete using various aggregate and concrete properties has been proposed. The effect of varying the proportion of low-grade aggregate in the mix has also been investigated. Possible mechanisms involved during abrasion have been discussed, including localised crushing and failure of the aggregate/paste bond. Aggregates from each of the groups were found to satisfy current specifications for direct finished concrete floors. This work strengthens the case for the increased use of low-grade aggregates in the future.

Apparatus and test methods for measuring the impact of golf balls on turf and their application in the field

An apparatus was developed to project spinning golf balls directly onto golf greens. This employed a modified baseball/practice machine with two counter-rotating pneumatic wheels. The speed of the wheels could be varied independently allowing backspin to be given to the ball. The ball was projected into a darkened enclosure where the motion of the ball before and after impacting with the turf was recorded using a still camera and a stroboscope. The resulting photographs contained successive images of the ball on a single frame of film. The apparatus was tested on eighteen golf courses resulting in 721 photographs of impacts. Statistical analysis was carried out on the results of the photographs and from this, two types of green emerged. On the first, the ball tended to rebound with topspin, while on the second, the ball retained backspin after impact if the initial backspin was greater than about 350 rads-1. Eleven tests were devised to determine the characteristics of greens and statistical techniques were used to analyse the relationships between these tests. These showed the effects of the green characteristics on ball/turf impacts. It was found that the ball retained backspin on greens that were freely drained and had less than 60% of Poa annua (annual meadow grass) in their swards. Visco-elastic models were used to simulate the impact of the ball with the turf. Impacts were simulated by considering the ball to be rigid and the turf to be a two layered system consisting of springs and dampers. The model showed good agreement with experiment and was used to simulate impacts from two different shots onto two contrasting types of green.

Germany at a crossroads:the gathering crisis sharpens

In our book, The Gathering Crisis: The 2005 Federal Election and the Grand Coalition (Miskimmon et al, 2009), we argued that the German political and economic systems faced a number of serious challenges. The resource crunch in public finances has been particularly problematic in a country used to consensus politics- money had previously been used to oil the wheels of German federalism (and European integration). In the light of recent events- the global financial crisis, the Eurozone crisis, the 2009 federal election- we claim that the crisis in the German political economy has sharpened. The task of Angela Merkel and subsequent chancellors will be to navigate the new era, ensuring that Germany remains a leading political and economic power in the European Union and beyond. © 2010 Macmillan Publishers Ltd.