Stack Volume Research Articles

3-D seismic imaging of complex structures in glacial deposits

A small‐scale, shallow‐penetration 3-D reflection seismic survey has been carried out over stratified glacial formations to test the method’s potential for delineating fine structural details with a reasonable field effort and cost. Recording was carried out with a 96-channel engineering seismograph. Blank shotgun shells were used as the energy source. Field records were obtained with usable reflection energy up to 500 Hz, exploring approximately a 220-m cubical volume. Although special processing was required to attenuate strongly dispersed and scattered surface waves, a stacked data volume of good quality has been assembled. More than 15 reflecting horizons with vertical resolution of about 1.5 m were clearly delineated within the Wisconsin sediments. Results are in good agreement with local outcrops and core information. The identified reflectors (interbeds) within the Late Wisconsin tills are extremely important. These reflectors may provide potential “hydraulic channels” for the movement of surface contaminants through the till into underlying aquifers.

A geometrical method for migrating 3D or 2.5D seismic reflection data

Classical processing of 2.5D land seismic surveys has shown to yield unsatisfactory images, even though shot gathers show clear reflections and a good signal to noise ratio. If some major interfaces are easily identified within the stack volume, their 3D geometry remains difficult to appreciate because of a lack of continuity in the cross‐receiver line direction. The theoretical aspects of an alternate method allowing a construction of these 3D structures are presented here. This method geometrically migrates picked reflection traveltimes on good quality shot gathers without amplitude or frequency considerations. It is tested on a synthetic dataset from a 3D smoothly deformed reflector that is well recovered by the technique and applied to major reflections of a 2.5D seismic survey, allowing a successful reconstruction of the reflectors.

Oxygen measurements in a mushroom compost stack

Oxygen concentrations and temperatures were measured in 9 representative regions of a section of a mushroom compost stack, to determine the relative rates of utilisation of oxygen by micro-organisms and replenishment of oxygen by movement of gases through the compost. Distinct patterns of change in oxygen concentration were identified. Oxygen concentration, integrated over the whole composting-time, was greater than 5% in 86% of the stack volume, but temperatures were above optimum for growth of thermophilic micro-organisms for most of the composting-time in 60% of the stack volume.

Efficient Utilization of Paulins in Fumigation and as Covers for the Protection of Storage

Formulas are given for determining the dimensions of the ideal stack which will give maximum volume under paulin covers used for fumigation or for the protection of storage. Some applications of the formulas are discussed, and a table is included which gives the ideal stack dimensions for paulins of various sizes and shapes when different amounts of overlap are provided for sealing. The study demonstrates the following: (1) The square is the best shape of paulin if the highest ratio of stack volume to paulin area is to be achieved. (2) The base of the ideal stack will resemble the shape of the paulin used to cover it. (3) Large paulins are innately more efficient than smaller ones because of the surface-volume relationship. (4) when two or more paulins are combined, greatest efficiency results if they are combined along the dimension that makes the difference between the length and width of the combined cover as small as possible, i.e ., when the combined cover is as nearly square as possible.