Performance analysis of the RC clampers in switching off no load arc furnace transformers
This paper presents an over-voltage attenuation performance analysis of RC clampers and surge arresters during transients caused by switching off a no load transformer applied to an arc furnace. A Brazilian Industry actual system was simulated using the Matlab/Simulink software. The simulation results indicate that the adequate use of RC clampers can reduce the arresters operations and practically eliminates the re-strikes and repetitive transient over-voltages when using vacuum circuit breakers to switch the arc furnace transformer.
Detailed study of fast transient phenomena in transformers and substations leading to an improved system design
In recent years several unusual failures were reported in medium voltage distribution systems. Some conventional dry-type and oil-filled transformers had clearly been exposed to a specific type of overvoltage. During thorough lab and factory investigations, no design or manufacturing faults could be found. Internal winding resonances were generally accepted to be the cause of the failure. This paper describes typical symptoms, critical factors and some ideas for appropriate protection and total system design, based upon experimental results from laboratory and on-site measurements. Laboratory tests are performed to investigate the high frequency behaviour of layer windings in distribution transformers. It is shown that multiple reignitions in vacuum circuit breakers can initiate internal winding resonances. Impulse tests confirm the resonance patterns at the natural frequencies. Long term high frequency measurements are performed in a medium voltage substation where problems have been detected before. The main purpose of the paper is to make system designers more aware of fast transient phenomena and to show that they represent a larger problem than generally accepted.
Metabolism of individual fatty acids by sheep depot adipose tissue in vivo and in vitro.
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1. Sheep adipose tissue and plasma have high stearate and low unsaturated fatty acid content compared to rat, dog and man. 
 
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2. In control animals in vivo uptake as well as release of various fatty acids by adipose tissue could be demonstrated. In vitro net release occurred. Fasting resulted in a decrease in tissue stearate and increased release of fatty acids. Adrenaline and noradrenaline had minimal lipolytic effect in vivo and in vitro. 
 
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3. Variations in the turnover rate of individual fatty acids were observed.