PubMed · 292150
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S T Olesen. 1978. Microelectronics in relation to hearing aids.. https://pubmed.ncbi.nlm.nih.gov/292150/
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Quantitative risk analysis for selection of safety integrity levels (SIL's) is becoming more prevalent due to the high equipment costs associated with qualitative methods. Procedures for applying quantitative methods to the SIL selection problem are in the early stages of development. Literature explaining quantitative methods is scarce and many engineers are forced to develop ad hoc procedures, some of which are mathematically flawed. One of the equations popularly used to assign a probability of failure on demand (PFD) to a safety instrumented function (SIF) based on tolerable risk and unmitigated event frequency is shown in the equation below. Variations of this equation are in use by various SIS practitioners: PFD(SIF) = f(Tolerable)_Risk/f(Unmitigated)_Event. This paper presents a rigorous derivation of this equation based on scientific laws of probability math and standardized definitions used in the field of SIS engineering. By publishing this derivation the author hopes to lend more credibility to this type of SIL selection process and increase its usage in the process industries.
An experimental setup for direct elemental analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy (LIPS, or laser-induced breakdown spectroscopy, LIBS) was realized. The combination of a echelle spectrograph, featuring a high resolution with a broad spectral coverage, with multivariate methods, such as PLS, PCR, and variable subset selection via a genetic algorithm, resulted in considerable improvements in selectivity and sensitivity for this complex matrix. With a normalization to carbon as internal standard, the limits of detection were in the ppm range. A preliminary pattern recognition study points to the possibility of polymer recognition via the line-rich echelle spectra. Several experiments at an extruder within a recycling plant demonstrated successfully the capability of LIPS for different kinds of routine on-line process analysis.
The distinctive features of well-defined, three-dimensional macromolecules with topologies designed to enhance solubility and amplify end-group functionality facilitated nanophase morphologies in mixtures with organosilicates and ultimately nanoporous organosilicate networks. Novel macromolecular architectures including dendritic and star-shaped polymers and organic nanoparticles were prepared by a modular approach from several libraries of building blocks including various generations of dendritic initiators and dendrons, selectively placed to amplify functionality and/or arm number, coupled with living polymerization techniques. Mixtures of an organosilicate and the macromolecular template were deposited, cured, and the phase separation of the organic component, organized the vitrifying organosilicate into nanostructures. Removal of the sacrificial macromolecular template, also denoted as porogen, by thermolysis, yielded the desired nanoporous organosilicate, and the size scale of phase separation was strongly dependent on the chain topology. These materials were designed for use as interlayer, ultra-low dielectric insulators for on-chip applications with dielectric constant values as low as 1.5. The porogen design, chemistry and role of polymer architecture on hybrid and pore morphology will be emphasized.