miscellanea The P 4 SR index-a critique of a recent criticism
In the October 1967 issue of this Journal there appeared a paper, entitled 'Assessing the Heat Stress and Establishing the Limits for Work in a Hot Mine' (Wyndham, Allan, Bredell, and Andrew, 1967), in which an account was given of an investigation conducted underground at Mount Isa Mine in Queensland. The purpose of the investigation was twofold: to determine which of three commonly used indices of heat stress wet-bulb temperature, corrected effective temperature, or the P4SR index predicts most accurately the effects on workmen underground of the several factors concerned in heat stress, and to decide, in terms of the selected index, at what level of heat stress the length of shift should be reduced or work should cease. The reason for undertaking the enquiry, despite the fact that heat-work tolerance has been investigated many times before, is stated by Professor Wyndham and his co-authors (p. 256,1 col. 1) to be that:
The Globe Thermometer in Studies of Heating and Ventilation
The effects of radiation and convection on the globe thermometer have been studied. Equations have been obtained, and alignment charts constructed, for the calculation of mean radiation intensity and of equivalent temperature from readings of the globe thermometer, air temperature and air velocity. The accuracy of these methods has been tested on observations made under industrial conditions. Taking direct thermopile observations as the standard, the mean radiation intensity values calculated from globe thermometer readings had an average error of 1·2 B.Th.U. per sq. ft. per hour. With eupatheoscope readings as standard, equivalent temperature estimates had a mean error of 1·2°. It is concluded that, while globe thermometer readings alone are unreliable as indications of the effects of the thermal environment, valuable results can be obtained by using the instrument along with an ordinary thermometer and a silvered kata-thermometer.
NUMBER OF TRIANGULATIONS OF A MÖBIUS STRIP
Consider a Möbius strip with n chosen points on its edge. A triangulation is a maximal collection of arcs among these points and cuts the strip into triangles. In this paper, we proved the number of all triangulations that one can obtain from a Möbius strip with n chosen points on its edge is given by 4n−1 + (2n−2 n−1 ) , then we made the connection with the number of clusters in the quasi-cluster algebra arising from the Möbius strip.