The calculation of the shadow factor of single coil filament
A computer method for calculating the power-reduction factor of a single-coil filament is presented. The filament of incandescent lamps is coiled, which is why a fraction of radiation is trapped in the filament. The relationships between the geometric parameters of a cylindrical helix (pitch ratio and mandrel ratio) and the shadow factor are developed. A FORTRAN program based on the numerical solution of algebraic equations and on three-dimensional numerical integration has been developed.<<ETX>>
A Predictive Theory of Power Balance in Incandescent Lamps
The design of filaments for incandescent lamps using traditional methods is often a lengthy process involving a series of lamp trials. This paper describes a theory of the operation of filament lamps which is capable of predicting the performance of a wide range of lamps to a high degree of accuracy but, because the theory presented in this paper disregards the existence of temperature gradients in the filament wire, it may not be applied to automobile and miniature lamp types. A more detailed theory applicable to miniature lamps is under development and it is hoped to publish the results in a future paper.
Palaeocarpinus (Extinct Betulaceae) from Northwestern China: New Evidence for Paleocene Floristic Continuity between Asia, North America, and Europe
Spiny-bracted fruits of Palaeocarpinus Crane, a genus of Betulaceae previously known only from Europe and North America, have been discovered in the Paleocene of Altai, northwestern China. The fruits are found in association with abundant Corylus-like foliage and staminate catkins containing Corylus-like pollen. Because of problems distinguishing leaves of Corylus from those of extinct betulaceous genera, we place these leaves in the genus Corylites Gardner ex Seward & Holttum. The fruits, staminate catkins, pollen, and leaves from Altai were probably all produced by a single species. Palaeocarpinus orientalis is nearly identical in its morphology to Palaeocarpinus joffrensis from the Paleocene of North America except in the more rounded primary bracts of the associated staminate catkins. The species is less similar to Palaeocarpinus laciniata from the Paleocene of southern England.