A multiparameter wearable physiologic monitoring system for space and terrestrial applications.

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described.     

Solidification microstructures in rapidly solidified,gas atomized aluminium-lithium alloy powders

The examination of the solidification behaviour and resultant microstructures in an Al-Li-Cu-Mg-Zr alloy processed by high-pressure inert gas atomization is reported. Using analytical transmission electron microscopy some quantification of the segregation behaviour is possible which allows the comparison with a simple solute redistribution model (Scheil analysis). It is shown that for powder sizes likely to be of commercial interest (10 to 20 m), cellular solidification structures are to be expected on atomization, and methods of utilizing such structures are discussed.     

Needs of caregivers of clients with multiple sclerosis

In an earlier study, an in vitro evolution procedure was applied to a large population of variants of the Tetrahymena group I ribozyme to obtain individuals with a 10(5)-fold improved ability to cleave a target single-stranded DNA substrate under simulated physiological conditions. The evolved ribozymes also showed a twofold improvement, compared to the wild-type, in their ability to cleave a single-stranded RNA substrate. Here, we report continuation of the in vitro evolution process using a new selection strategy to achieve both enhanced DNA and diminished RNA-cleavage activity. Our strategy combines a positive selection for DNA cleavage with a negative selection against RNA binding. After 36 "generations" of in vitro evolution, the evolved population showed an approximately 100-fold increase in the ratio of DNA to RNA-cleavage activity. Site-directed mutagenesis experiments confirmed the selective advantage of two covarying mutations within the catalytic core of the ribozyme that are largely responsible for this modified behavior. The population of ribozymes has now undergone a total of 63 successive generations of evolution, resulting in an average of 28 mutations relative to the wild-type that are responsible for the altered phenotype.     

A case for the VMEbus architecture in embedded systems education

The VMEbus is an IEEE standard architecture upon which many embedded and real-time systems are built. The VMEbus architecture has existed for nearly 25 years and has been used extensively for military, industrial, and aerospace applications. This paper describes the general characteristics of the VMEbus architecture, specifically relating these characteristics to aspects of embedded systems education included as components of the IEEE/ACM CE2004 computer engineering model curriculum. Portions of this model curriculum are currently being implemented at universities across the country as part of an increasing effort to address the need for embedded systems education. This evaluation will identify the strengths and weaknesses of this architecture as a general-purpose embedded systems educational tool. The VMEbus architecture is used in the laboratory component of an undergraduate embedded systems course at the University of Alabama (UA), Tuscaloosa. The assessment results evaluating its effectiveness are presented.     

The effect of Ni on the decomposition of austenite in Fe-Cu alloys

This paper is concerned with the effect of ternary additions of Ni on the decomposition of austenite in Fe-Cu alloys. It is shown that the transformation kinetics, transformation structures and associated precipitate morphologies are sensitive functions of the Ni content. Specifically the results show that the addition of nickel increases the transformation times and also leads to a change in resultant ferrite morphology from equiaxed to Widmanstätten, with a concomitant increase in the partially coherent interphase boundary growth mode. The increase in transformation time allows precipitation of Cu to occur on the interphase boundary and in the matrix. It is also shown that the exact details of the ∈-Cu dispersion is controlled both by the nature of the austenite/ferrite interface and the kinetics of the transformation.     

The nature of acicular ferrite in HSLA steel weld metals

In this paper, the nature of the fine interlocking acicular ferrite microstructure in HSLA steel weld metals is investigated. The results strongly suggest the acicular ferrite is comprised of intragranularly nucleated Widmanstätten ferrite. Further, it is shown that the active nucleation sites for this ferritic product are weld metal inclusions. Sympathetic nucleation then takes place which leads eventually to the fine, interlocking microstructure which is a characteristic of acicular ferrite.