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The state of the art relative to the measurement of shock and detonation pressures of the magnitude generaled by condensed high explosives is reviewed. Carbon resistors have been shown to provide a relatively inexpensive and direct method for such measurements, provided adequate calibration data are available. The gauge is fabricated by heat‐sealing the carbon resistor (470 Ω, 0.125 W) into a suitable plastic material such as polystyrene; when subjected to a strong shock wave, the gauge undergoes compression and the conductivity increases in proprtion to the magnitude of the pressure. The present investigation was concerned with the experimental derivation of calibration equations relating the pressure (in gigapascal) as a function of the conductivity change ΔG (in siemens). The point of inflaction occurring at approximately 2.36 GPa, corresponding to 0.02082 S, is in agreement with previous observations in the literature. Additional experiments are being planned to resolve a problem concerning oscillatory ringing in the gauge voltage records.

Precise quantification of the oval of a bird egg can provide a powerful tool for the analysis of egg shape for various biological problems. A new approach to the geometry of a bird egg oval is presented here using a simple algebraic equation to fit all normal bird egg shapes. Only two parameters are needed in the equation for complete shape description of an egg oval to quantify the equation's capacity for curve fitting all species and shapes of bird egg ovals. The equation was fitted to egg silhouettes from a sample of 250 different bird egg species containing one egg per species. Standard regression analysis was used to fit the equation to each egg profile. The 99% CI for the curve fit acceptance rate was calculated to determine the equation's statistical significance for all species of bird eggs. Compared to the power series multiequation models (Preston 1968, Todd and Smart 1984), the equation used here is the simplest analytic description of a bird egg oval.

An estimate of the detonation pressure of carbohydrate‐metal composite explosives has been obtained experimentally by use of carbon resistor pressure gauges mounted in the wall of the confining tubes. The composite explosives were formulated from a pharmaceutical mixture of 10/90 nitroglyccrin/ß‐lactose by weight, and was rendered detonable by inclusion of flaked aluminum and both flaked aluminum and ammonium perchlorate. The detonation pressure of the nitroglyccrin/ß‐lactose mixture with 10 percent aluminum by weight was approximatcly 1.1 GPa. The incorporation of 30 percent ball‐milled ammonium perchlorate to this formnlation increased the detonation pressure to 12.2 GPa. These pressures must be considered as estimates of the true detonation pressure, because of (a) the suspected non‐ideality of the detonation state of these explosives, (b) the statistical nature of the response of the gauges, and (c) possible inconsistencies in the interpreatation of the gauge records. It is recommended that a number of gauges be used in a given experiment, and the results be averaged as one means of cireumventing the above difficulties.

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