River Lune Pollution at Lancaster in July 1949

Houses close to River Lune at Lancaster, North West England, UK. This photo shows the polluted River Lune in July 1949. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

On the selective removal of steel by laser-assisted vortex machining

Of all laser-based processes, laser machining has received little attention compared with others such as cutting, welding, heat treatment and cleaning. The reasons for this are unclear, although much can be gained from the development of an effcient laser machining process capable of processing diffcult materials such as high-performance steels and aerospace alloys. Existing laser machining processes selectively remove material by melt shearing and evaporation. Removing material by melting and evaporation leads to very low wall plug effciencies, and the process has difficulty competing with conventional mechanical removal methods. Adopting a laser machining solution for some materials offers the best prospects of effcient manufacturing operations. This paper presents a new laser machining process that relies on melt shear removal provided by a vertical high-speed gas vortex. Experimental and theoretical studies of a simple machining geometry have identifed a stable vortex regime that can be used to remove laser-generated melt effectively. The resultant combination of laser and vortex is employed in machining trials on 43A carbon steel. Results have shown that laser slot machining can be performed in a stable regime at speeds up to 150mm/min with slot depths of 4mm at an incident CO2 laser power level of 600 W. Slot forming mechanisms and process variables are discussed for the case of steel. Methods of bulk machining through multislot machining strategies are also presented.

Transfering pike to Lancaster Canal, March 1950

Two fishermen transfering pike using metal containers to the Lancaster Canal, North West of England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

The Kendal, Lancaster and Preston canal fishery

This is the Kendal, Lancaster and Preston canal fishery produced by Lancashire River Authority in 1970. The Kendal-Lancaster-Preston canal commenced at Stainton in Westmorland and terminated on the outskirts of Preston. Fishing in the canal with rod and line was controlled by the Northern Anglers’ Association. In the early 60’s anglers, had complained about, the extremely low numbers of fish that had been caught in the canal and various opinions had been expressed concerning the alleged shortages o f fish. Since 1967, in an endeavour to meet the fish re-stocking demands of the Association, 50,000 freshwater fish of different species had been introduced by the Lancashire River Authority, but catches had not increased. In 1969 was agreed by the Northern Anglers’ Association to carry out a study of the fish populations throughout the whole length of the canal and the chemical quality of the water analysed. This report is not produced as a scientific dissertation, but rather as a means of imparting to members of the Northern Anglers’ Association the fish potential available to them in their endeavours to catch fish.