Controlling the variable of pressure in the production of test footwear impressions

Footwear impression lifting and enhancement techniques may be affected by several variables introduced during the production of test footwear impressions, thus limiting the usefulness of enhancement technique comparisons and the results obtained. One such variable is the force applied when the impressed mark is being made. Producing consistent test impressions for research into footwear enhancement techniques would therefore be beneficial. This study was designed to control pressure in the production of test footwear impressions when mimicking a stamping action. Twenty-seven volunteers were asked to stamp on two different surfaces and the average stamping force was recorded. Information from the data obtained was used to design and build a mechanical device which could be calibrated to consistently deliver footwear impressions with the same force onto a receiving surface. Preliminary experiments using this device and different contaminants on the footwear sole have yielded consistent and repeatable impressions. Controlling the variable of pressure for the production of test impressions in this study demonstrated that the differences observed were visual (due to the amount of contaminant transferred and subsequent enhancement) and did not affect the replication of outer sole characteristics. This paper reports the development of the device and illustrates the quality of the impressions produced

Clarification of route specific impurities found in methylamphetamine synthesised using the Birch method

This paper focuses on the determination of route specific impurities produced when methylamphetamine is synthesised using the Birch reduction. Previous work available in the scientific literature reported only one route specific impurity using ephedrine hydrochloride as the starting material. In this paper we investigated the impurity profiles of methylamphetamine produced from both the salt and base forms of ephedrine and pseudoephedrine. A new previously unreported route specific impurity was revealed as was the potential absence of the previously reported impurity in the profile of samples prepared from the free base