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Notes: Pork chops from 96 fresh loins representing PSE, normal and DFD quality were displayed in a supermarket. Price was not altered and equal numbers of the three quality types were presented in a manner disguising any evidence that a survey was in progress. A total of 280 packages were purchased. Over one-half (146) of the purchases included packages of normal chops (P 〈 0.001), whereas the remaining purchases were divided between DFD (72) and PSE (62) packages. These findings suggest that some consumers may be aware of and may activiely select for ‘normal’ pork color, but that others are either unaware of the liminations of, or do actually prefer, PSE and DFD pork.

Notes: For horizontal layering and plane horizontal impulsive wavefronts it is theoretically possible to get rid of multiple reflections by a feedback procedure which can easily be derived using raypath philosophy. To reduce the increase of noise inherent in the method the precise theoretical formulae are altered in such a manner that a practical application becomes possible. For this purpose the autocorrelation will be used.Application of the new process to a CRP section where the shot geophone distances in the field had not been long enough to attenuate multiple reflections effectively gave favourable results.

Notes: There are various methods of measuring the porosity of rocks. The direct methods are based on the definition of the porosity ratio. The indirect procedures, which have often been adopted purely for economic reasons require interpretation methods that relate certain measured quantities to the porosity ratio.In the present article, the relationship between acoustic velocity and porosity will be examined. The interpretation method most commonly in use today is based on an approximative equation developed by Wyllie, Gregory and Gardner. This equation obtains the travel time of acoustic waves in a porous medium saturated with liquid by linear interpolation with respect to the porosity n between the travel time T0 in the compact medium (n= o) and the travel time T1 in the pure liquid (n= 1).As observed values of the travel time T differ from those that follow from this linear equation, it seems obvious to attempt a higher degree of approximation, e.g. by means of a polynomial of the third degree.Besides T0 and T1 other quantities are needed in order to obtain the coefficients of such a polynomial. These quantities must bear some relation to the physical constants of the rock. Only in the neighbourhood of n= o and n= 1 is it possible to make general statements concerning the behaviour of rocks and, in particular of the skeleton. Therefore, in the points n= o and n= i not only the values of the approximative function T=f(n) itself are given, but also those of its derivative with respect to n. The values of these derivatives ∂T/∂/Tn=0 and ∂T/∂/n-1 depend on the properties of the material filling the pores and on data concerning the structure of the skeleton and the stresses in it. The considerations leading to a mathematical formulation of this dependence are dealt with in this article.The elastic constants of the skeleton were developed in Taylor series in n, that, for skeletons with low porosity were truncated after the linear term. The coefficients of n are functions of the constants of the material of the skeleton, the shape of the pores and the stresses in the skeleton. These functions were approximately computed for two limiting cases. For a more general application, it is useful to assume that these coefficients are the same for both Young's modulus and Poisson's ratio and then obtain the functional relation between the coefficient and the residual pressure from measurements performed in the laboratory with various kinds of rock. When this relation is established from such laboratory experiments, the cubic interpolation method can be applied.Whereas the linear interpolation method, as it has been in use up to now, presents a relation between porosity and acoustic velocity only, the cubic interpolation method makes it possible to determine the influence of pressure and the state of cementation of the rocks. Comparison with data obtained from direct measurements shows good agreement.

Notes: The purpose of the automatic gain control in seismic amplifiers is to balance the slow decrease of the signal in such a manner that its energy does not exceed the capacity of the recording system. At the same time the interesting seismic content of the signal has to be preserved as undistortedly as possible. At first, the technical data of AGC circuits are calculated. The characteristic curves of circuits with one, two, and three time constants are computed. In circuits with two and more time constants an oscillating of the AGC is possible. In order to guarantee aperiodic operation, the ratio of the time constants must not fall below a certain value. As long as these technical conditions are complied with, the free choice of the largest time constant remains open and can be accommodated to the geophysical conditions.From the endeavour to balance the slow decrease of the signal as well as possible, an upper limit for the choice of the time constants can be derived. A lower limit is obtained from the condition that the seismic content of the signal has to be preserved. The determinant time constant should lie between the two limits and differ from them as much as possible.Finally, the problem of the amplifier “squeezed” by energy pulses is touched.

Notes: In order to find a relation between Poisson's constant of dry sediments and the porosity, it is necessary to consider the elastic behavior of the sediment's initial state and the final state during the process of consolidation. Sand and other loose materials of more or less granular substances represent the initial state. As substitute for this zone, elastic constants of simple cubic and hexagonal packing are examined. Supposed is the adhesion for the planes of contact. Besides of Hertz's formula for the contact area of spheres, an elastic function of displacement due to a tangential force for the contact area of the spheres is used. This function has been derived. With the aid of these two. elements, the constants of the mentioned packing are calculated. Poisson's constant will then be calculated from the formula being valid for isotropic solids 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR204:GPR_204_mu1" location="equation/GPR_204_mu1.gif"/〉 for three different directions of the sound. The mean value is lying at 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR204:GPR_204_mu2" location="equation/GPR_204_mu2.gif"/〉.With the known equation of Poisson's constant of rock having a small porosity, a third-degree polynomial is formed. This polynomial agrees well with the average values of known measurements, and therefore can serve as a guide for the calculation of Poisson's constant of water-saturated sediments.