Honeycomb Type Research Articles

Cross‐Flow Heat Exchangers—Part II

AS the rate of heat transfer by forced convection from a fluid to a metal surface is relatively low, it is necessary to provide a large area of metallic surface while keeping down the overall volume of the exchanger. One design of exchanger which meets this requirement very effectively is the honeycomb type of construction shown in FIG. 11.

A Note on the Eigenvalue Problem in Crystal Statistics

mathematical theory of order-disorder transition. The problem of determining the partition function for a lattice with simple interaction model was found, by severai authors,!) to be reduced to an eigenvalue problem which is easier to handle with,and which, with suitable approximations, would reveal more refined details of the phase transition than the former theories. This method of attack culminated in the work of Onsager,2) who succeeded In giving the rigorous solution of the above mentioned eigenvalue problem for two-dimensional simple square Ising lattice. The mathematical tools involved, however, are so hopelessly complicated that one would quite simply lose sight in the jungle of hypercomplex numbers. A con­ siderable improvement on this mathematical point has been attainp.d by Husimi and Syozi3) who used it to solve the eigenvalue problem for the honeycomb type lattice. The present author, independently of them,' has reached more or less similar ideas and considerations. which it is the purpos~ of the present paper to expose in brief detail. Though as yet no substantial applications has been attempted, nor anything physically new has been derived, it may be hoped that it will do some profit for those who are interested in such problems.

Roentgenographic Features of Skeletal and Extra-Skeletal Lesions in Some Diseases of Children

MANY conditions of disturbed metabolism and disease in children are known to be accompanied by changes in the skeleton that are quite characteristic. Some of these conditions are of rather common occurrence, and in most instances the presence of changes in the skeleton can be predicted with reasonable certainty. In others, the condition is not so apparent and is disclosed only by roentgenologic study. Renal Rickets The roentgenographic appearances of the bones in cases of renal rickets have been described in some detail by Parsons. He divided cases into three kinds: (1) the atrophic type, with fragile, atrophic, osteoporotic appearances, lines of cancellous tissue at the epiphyseal ends of the diaphyses, and a thin atrophic cortex and fractures of the shaft; (2) the florid type, with changes characteristic of florid rickets, and (3) the woolly, stippled, or honeycomb type, with swollen epiphyseal ends of the shaft and a honeycomb, stippled, or woolly appearance of this portion of the bone. The bone looks ...