The project had the following aims: -To improve process control in the zinc, copper and electronic industry through the use of high temperature solid sensors. -To identify and create new solid electrolyte sensors for the determination of aluminium in zinc for specialist galvanizing. -To improve the lifetime of solid state sensors in high temperature melts. The reports from individual partners show that Dr Hampson, at Ion Science, has continued to optimize the design and materials of construction together with the identification of alternative electrolytes and fabrication techniques. Considerable study and testing of Ca, Na and Sr ß alumina has been undertaken, whilst batches of sensors have been manufactured and delivered to Britannia, MIM, Enirisorse and Union Minière at Olen. In addition to the continuation of laboratory testing of sensors, alternative methods of forming electrolyte tubes have been extensively tried. Late in the period a new inverted cup design of oxygen sensor was developed. The team at Britannia Zinc have re-designed their sensor insertion facility, obtained, installed and tested their data handling system and continued to undertake trials with sodium and arsenic sensors prepared according to the prototype design by Ion Science. Britannia have provided melt and master alloy samples to Ion Science and Leeds. MIM Duisburg hosted a trial undertaken by Dr Kale, Leeds and Mr B Harris of BZL, together with Dr Hampson of Ion Science. They spent considerable time and effort in order to establish and validate a sampling regime that served to provide a reliable correlation with sensor readings during trials. In addition, they have carried out an assessment and evaluation of other sheath materials, such as enamelled mild steel, as part of the long-life investigation within the project. Dr Vangrunderbeek was responsible for the programme at VITO, who developed an electrolyte production and supply facility and their close proximity to Union Minière, at Olen, has assisted the development of the test programme with UM on oxygen in copper sensors. VITO have applied latest electron microscopy and micro probe analysis to assess the performance of sensors after immersion. They were also responsible for maintaining links with Galva Oost, a galvaniser acting as an endorser in the project. Dr Kale and Mr Davidson, working at Leeds, carried out laboratory development work on the arsenic and aluminium sensor and different sensor assembly techniques were researched. In addition, Professor Fray and Dr Kumar, now at Cambridge, have provided both theoretical assessment and design assistance. Practical help with on-site plant trials at Avonmouth was provided by Mr Davidson. Enirisorse, represented by Dr Emilio Sentimenti, who joined the project at the beginning of year 2, set-up their laboratory test facilities and undertook testwork on their copper, using sensors supplied by Ion Science. Concepts for engineering the sensors into the anode refining furnace have been considered.