Mechanical properties of lettuce

The fracture properties of Spanish Iceberg and English Round lettuce tissues were investigated using a tensile test on notched specimens. The level of notch sensitivity was investigated for samples of differing colour and vein orientation. Vein orientation perpendicular to the test direction proved to be the most notch sensitive and samples with vein orientation parallel to the test direction proved to be very notch insensitive, samples with a diagonal (45°) orientation showed an intermediate response. This response was interpreted in terms of the interaction of veins with the crack path. The strengths of English Round tissues were broadly comparable with those of Spanish Iceberg although the upper limits depended on vein orientation and were in the order: parallel > diagonal perpendicular. A similar ranking of vein orientation was found in estimates of stiffness.     

A tutorial on biomedical process control

This paper presents a tutorial on five typical applications within the area of biomedical process control. The specific applications discussed include: control of insulin administration for treating diabetes mellitus, dynamic modeling for anti-cancer chemotherapy regimen design, modeling and control of drug infusion in critical care, structured treatment interruptions: a control mathematical approach to AIDS protocol design, and dynamic modeling and control of the anticoagulant drug heparin. The objective of the tutorial is to illustrate the rich and important set of problems within the biomedical area that process control engineers can contribute to solving. Solution to these problems can have a significant medical as well as economic impact.     

Tropical forest cover dynamics for Latin America using Earth observation data: a review covering the continental,regional, and local scale

The tropical forest cover has varied greatly over the last few decades. The rapid advance of agricultural crops and illegal clearings in natural areas has resulted in the conversion of the majority of the world’s forest into desolated patches. Although rates of deforestation have decreased compared to previous years, forest loss still remains a crucial concern. Latest studies conducted on a global scale identified the Latin American continent as one of the regions exhibiting the highest rates of deforestation in the world. The dynamics of forests over the past 40 years has attracted numerous remote-sensing-based studies to monitor forest loss, analyse patterns, and understand the drivers of land conversion. This review article provides a comprehensive overview of the remote-sensing-based studies of tropical forest dynamics in Latin America. Following an introduction with respect to global forest mapping products, a general outline of tropical forest ecoregions and drivers of deforestation in Latin America is provided. Subsequently, a review and categorization of the existing studies is presented, where focus is laid on selected sensors and data analysis methodologies apply. Furthermore, a case study for the whole of Paraguay is presented; Paraguay is a region which contains highly diverse ecosystems that have been ravaged as a result of deforestation over the past 40 years. The main results, challenges, and future needs are discussed.     

THE UNSOLVED MESSAGES OF PEARL HARBOR

In 1941, the United States Navy intercepted enough Japanese naval messages to predict the attack on Pearl Harbor if the code which protected them had been solved. The messages would have disclosed that, while the Japanese government cynically conducted diplomatic negotiations with the United States, the Japanese Combined Fleet under Admiral Isoroku Yamamoto, beginning as early as September 1941, systematically prepared ships, crews, weapons, tactics, and a complicated fuel supply system for the most ambitious operation ever undertaken by the Japanese navy. Details of Japan's intentions were hidden from Navy cryptanalysts because of limited manpower resources and because all Japanese navy codes were assigned a lower priority than Japanese diplomatic codes and German submarine threat.     

FROM THE EDITOR

Abstract

So far we've survived the first three months of this last year of the millennium. We hope we have all made our final Y2K preparations and are just waiting for the clock to tick down. OK, OK … well, not all of us …. But, even so, perhaps we can start to turn the corporate focus away from the problem of the century just enough to start the collective mind thinking and investing money in its information security programs.     

The Rosemanowes HDR project 1983–1991

The Rosemanowes HDR project in the period 1983–1991 continued experiments in HDR reservoir creation at depths of up to 2500 m in Cornish granite. A viscous gel stimulation was followed by an extensive characterisation of the reservoir created, using a long period of continuous circulation. The possibility of manipulating the system to improve its performance was explored, using secondary stimulations, placement of proppants in joints entering the production well, production pressure control using downhole pumps, and sealing sections of the production well to by-pass ‘short-circuits’. Proposals were made for a ‘multi-cell’ reservoir design, connecting cells in parallel between injection and production wells. The work of the Rosemanowes team has been concentrated on HDR projects outside the UK since 1991.     

Rubber modification of low temperature cure cyanate ester matrices and the performance in glass fabric composites

Low temperature cure cyanate ester resin systems were developed and modified with epoxy‐terminated butadiene acrylonitrile rubber (ETBN) and impregnated into woven glass fabric. Mode I and mode II interlaminar fracture toughness values of the cured laminates were evaluated as a function of rubber concentration. Mode I fracture toughness increased to almost twice that of the unmodified system, while mode II fracture toughness remained essentially unchanged. Composite samples were subjected to aging experiments in water and the absorption/desorption behavior was investigated as was the effect on thermal performance. The presence of rubber was found to reduce the rate of matrix deterioration but also caused a substantial increase in water uptake. It was found that although the addition of rubber to the matrices decreased the unconditioned (dry) T_g all specimens showed the same reduction in T_g, after equilibrium water absorption.