More windmill shut-offs

Since we printed the description of a type of automatic windmill shut-off used on Abydos Station, Port Hedland, in the issue of December, 1951, several readers of the Journal have written to describe alternative methods of pulling a mill out of the wind when the tank is filled. In a number of cases there were variations of the same idea, and in this article the main principles are described, together with some other ingenious gadgets which the author has encountered over the years

Some instructive field days

Although fully conversant with the old newspaperman\u27s adage which states that Yesterday\u27s news is the bath-heater fuel of today, we make no apology for including these reports of field days held after our December issue had gone to press. It is felt that they contain some useful lessons which, even at this late date, are deserving of emphasis

Maximal inequalities for fractional L\'evy and related processes

In this paper we study processes which are constructed by a convolution of a deterministic kernel with a martingale. A special emphasis is put on the case where the driving martingale is a centred L\'evy process, which covers the popular class of fractional L\'evy processes. As a main result we show that, under appropriate assumptions on the kernel and the martingale, the maximum process of the corresponding `convoluted martingale' is $p$-integrable and we derive maximal inequalities in terms of the kernel and of the moments of the driving martingale