Pyrographit – Eigenschaften und anwendung

Pyrolytic Graphite – Properties and Application The carbon material known as pyrolytic graphite is remarkable for its exceptional properties which make it capable of being used in fields and processes in which high thermal, chemical and electrical stress is required. Its technical importances has increased in recent years. A report is given of the preparation of pyrolytic graphite and also of its important application properties, and the most important fields of application are touched on.     

Bayesian Inference of Nanoparticle-Broadened X-Ray Line Profiles

A single-step, self-contained method for determining the crystallite-size distribution and shape from experimental x-ray line profile data is presented. It is shown that the crystallite-size distribution can be determined without invoking a functional form for the size distribution, determining instead the size distribution with the least assumptions by applying the Bayesian/MaxEnt method. The Bayesian/MaxEnt method is tested using both simulated and experimental CeO₂ data, the results comparing favourably with experimental CeO₂ data from TEM measurements.     

Waking up the gastric bypass patient

Waking up the gastric bypass patient in the post-anesthesia care unit (PACU) is a continual challenge. From January 1992 to November 1996, 961 gastric bypasses (GBP) have been performed at Columbia St Mark's Hospital. Of the 961 patients, 957 came to the PACU. Four patients went directly to ICU because of respiratory status requiring mechanical ventilation. There have been no deaths and no respiratory arrests in PACU. Continuous bedside monitoring of the patient's respiratory status coupled with pain management contributed to positive care of the GBP patient. Methods of care for the GBP patient include the use of O2 masks and cannulas, coughing and deep breathing, administering i.v. narcotics until patient controlled analgesia pumps are initiated, encouragement and emotional support, ongoing assessment of patients' status, and treating problems/needs appropriately.     

A system for simulation, monitoring and diagnosis of controlled continuous processes with slow dynamics

This paper presents a modelling approach specifically designed to be used in a monitoring and diagnosis system based on the simulation of relevant process and control system variables. The model is based on semantically extended data flow diagrams with each computational process representing the incremental behaviour of a component of the plant to be modelled. Variable as well as delay time behaviour is associated with each component model to support an event-driven simulation which, in turn, reduces computation time. This plant model of independent but interacting computational processes is easily extendable, modifiable and adjustable according to changes in the plant.

The modelling approach is applied to a coal power plant process and is implemented in G2, an object-oriented, real-time expert system shell with built-in simulation and online external connection capabilities. Generic rules guiding the event-driven simulation and monitoring allow for modular adaptation of the model as the plant's structure and functionality change without requiring changes in the rule set.     

Design and Performance of an Integrated Analytical Swatch Testing System

Abstract

An integrated swatch testing system for precisely quantifying the resistance of chemical protective materials to permeation and penetration by a chemical weapons agent (CWA) simulant is described. The analytical variability of methodologies currently used by Department of Defense testing laboratories was dramatically reduced by modifying the test cell and experimental procedures while maintaining compatibility with military testing specifications. Utilizing an on-line calibration system, cryogen-free preconcentrator, and flame ionization detector, the integrated system has demonstrated excellent repeatability, reproducibility, and high sampling frequency for a variety of non-porous and air-penetrable swatch samples challenged with methyl salicylate.     

The relationship of microstructure to mechanical properties of Al-, Si-, K-doped tungsten wire

Tungsten wire, commercially doped with aluminium, silicon, and potassium, was obtained from six different manufacturers with a diameter of 0.0063 cm. The tensile strength at 1620 °C, a measurement of the quality of the wire used by the General Electric Company, was determined and found to be different for each wire. Additional samples of wire were annealed at 1620 °C under the same conditions employed for the tensile test. To determine the microstructure, these samples were thinned for transmission electron microscopy along with the wires in the as-drawn condition. The widths of from 75 to 125 subgrains were measured for each sample. In addition, in the annealed samples, the spacing of the strings of potassium bubbles was also determined. It was found that the 1620 °C tensile strength was related to the increase in width of the subgrains during the 1620 °C anneal and that the amount of subgrain widening was determined by the spacing of the strings of bubbles. Hence, the 1620 °C tensile strength was related to the bubble string spacing; the closer together were the strings, the higher was the 1620 °C tensile strength. It was also shown that the grain morphology of the wire, as measured by the stretch or sag of a filament during a stress test, is also determined by the spacing of the strings of potassium bubbles.