A mechanical device for eradication of submerged aquatic weeds

This paper embodies details and method of operation of a mechanical device developed for eradication of submerged aquatic weeds. The economics of operation is also discussed.

INFLUENCE OF ATMOSPHERIC COMPOSITION ON THE ABRASIVE WEAR OF TITANIUM AND Ti-6Al-4V.

A pin-on-disc apparatus has been used to investigate the wear and friction (sliding force) behavior of metals on bonded silicon carbide and alumina papers under conditions of controlled atmospheric composition. The wear rates of both commercial purity titanium and the alloy Ti-6%Al-4%V tested in air were found to remain constant with time, in contrast with the behavior of other metals tested under similar conditions, which exhibited a progressive decrease in wear rate with increasing number of passes along the same track. It is proposed that the concentration of interstitial nitrogen and oxygen in the worn metal surface, which largely determines its mechanical properties, strongly influences both the ductility of the abraded material and the force of adhesion between the metal and the abrasive particles. Parallels are drawn between abrasive wear and machining to illustrate the importance of oxygen at the interface between workpiece and tool surfaces.

Materials selection in mechanical design

A novel materials-selection procedure has been developed and implemented in software. The procedure makes use of Materials Selection Charts: a new way of displaying material property data; and performance indices: combinations of material properties which govern performance. Optimization methods are employed for simultaneous selection of both material and shape.