An orthogonal form of the Schwarzschild metric

An orthogonal form of the Schwarzschild metric is given and the transformation relating this form to the standard one is found.     

Control of rotary lawn mower noise

The current state of knowledge regarding the noise generated by rotary lawn mowers is reviewed, with emphasis on the role of the rotating blade. Noise control methods are discussed and evaluated.     

Determination of bismuth oxide in and on high-purity bismuth

Bismuth is dissolved in mercury on shaking with ammonium nitrate solution in a nitrogen atmosphere; bismuth oxide is insoluble and so can be separated by flotation and dissolved in nitric acid for spectrophotometric determination as tetraiodobismuthate(III). The method is applied to various bismuth samples containing about 0.01% Bi₂O₃, the relative standard deviation being 7–11%.     

Aluminum-chloride catalyzed reaction of allylic sulfides with methyl propiolate: A novel addition reaction via an ionic [3.3] sigmatropic rearrangement

The aluminum-chloride catalyzed reaction of allylic sulfides with methyl propiolate resulted in the clean formation of novel 1:1 adducts via ionic [3.3] sigmatropic rearrangements.