Compliance Variation Research Articles

HPLC analysis of 6-mercaptopurine and metabolites in extracellular body fluids.

A convenient HPLC assay, which allows for the simultaneous measurement in extracellular fluids of 6-mercaptopurine and four of its metabolites, 6-thioguanine, 6-mercaptopurine riboside, 6-thioxanthine and 6-thiouric acid is described. Solid phase extraction allows for the clean isolation of analytes from plasma, urine or cerebrospinal fluid. The simultaneous determination of 6-mercaptopurine and some of its major metabolites in extracellular fluids may contribute to the monitoring of patient compliance, bioavailability, and individual variation in metabolism and absorption.

The fracture energy and acoustic emission of a boron-epoxy composite

The fracture surface energy (γ) of a boron fibre-epoxy resin composite has been measured by three different techniques: work of fracture, linear elastic fracture mechanics, and compliance variation. Significant differences were obtained by the different methods. The compliance data were analysed to giveγ at different stages of crack propagation. It was observed thatγ decreased as the crack entered the material and that this variation ofγ could be correlated with the pull-out length of fibres and acoustic emission generated during fracture. The fracture surface energy is explained in terms of a debonding model.

Report on the progress and present state of our knowledge of hydraulics as a branch of engineering

Though pneumatic actuators are widely used in industrial applications, it is not easy to control them because of the nonlinearities in the valve, the compliance variation and the generating force. In this paper, a method of feedback linearization is applied to a pneumatic actuator system to handle the nonlinearities. It is shown that any single-input pneumatic system with a linearizable load and an isothermal pneumatic actuator is linearizable by state feedback. In addition, feedback linearization with step-type disturbance rejection is proposed by measuring disturbances, which is useful for pneumatic systems with static friction. Experiments with a rubber artificial muscle actuator that has hysteresis characteristics caused by static friction are carried out, and verify the effectiveness of the proposed method.