Abstract: The invention enables the rooftop cultivation of turf which can both be walked upon and which also helps prevent temperatures from rising in rooms below the roof by shielding it from the sun. The structured cultivation medium itself comprises three layers of synthetic plastic material, a top layer for turf cultivation, a middle layer to protect the roots and a bottom layer to drain water away. A root blocking waterproofing layer is laid on the surface of the roof slab to waterproof the building and to guard against the downward encroachment of roots. A net is also laid on top of the turf both to prevent it from being damaged by wind and also protect it against concentrated loads.

Abstract: A sensor for use during the construction of a concrete structure to enable an assessment to be made of whether or not a pour of fresh concrete has settled uniformly throughout the placement area. One of two main electrodes is fitted with an auxiliary electrode in parallel such that the polarity of the electrodes is reversed when they are immersed in water and when they are immersed in fresh concrete. By monitoring this function, it is possible to detect the presence or absence of fresh concrete in accordance with the polarity. In the case of a sensor without an auxiliary electrode, it is still possible to monitor changes in the voltage level when the electrodes are immersed in water and in fresh concrete, thereby providing access to a similar mode of assessment.