1,042 research outputs found
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Q2S Enhancing Pedagogy - Lowering DFW rates for Large Lecture Courses
This is a report indicating effective actions I took to lower my DFW rate for a large lecture, general education history course, World History
Information, Meaning and the role of Semiosis in the Development of Living Systems
The claim here is that semiosis is concomitant with life and not simply one of several possible adaptive mechanisms. Signs, particularly indices, serve as steering mechanisms for even the most primitive organisms, completing a circuit between the detection of energy sources and behavior that is conducive to acquiring those sources. Without that kind of agency, no form of life is possible. To show this, an understanding of the interrelation among energy, matter, information, and meaning is required, and how they are interlaced in the notion of work. One specific thesis of the paper in this respect is that meaning is the propagating work of information. Peirce’s theory, with some modifications, can be used to articulate this account of things, and brings a powerful analytical tool to the problem
New techniques for the production of high-performing industrial enzymes
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Estimation of the chemical specific surface area of catalytic nanoparticles by TEM images analysis
Purpose: The purpose of this article is the development of quantitative methods for
assessing the quality of nanocomposite materials used in fuel cells.
Design/methodology/approach: latinum is the most commonly used catalyst in fuel
cells, commonly in the form of nanoparticles deposited on the surface of carbon black.
Due to the nanometric size of platinum particles, transmission electron microscopy can
be applied to evaluate the produced catalysts. TEM image also allow to determinate the
approximate value of the chemical specific surface area) of platinum nanoparticles, but only
in case of spherical particles.
Findings: In present work, taking into account additional assumptions resulting directly from
the analysis of microscopic images, the method of estimation of the particle diameter and
the chemical specific surface area for nonsymmetrical (elongated) nanoparticles is present.
Research limitations/implications: The presented work presents a method for
determining the specific surface of platinum, when their shape is elongated. It is worth
noting that the modified formulas for determining the particle diameter and the value of
the chemically active specific surface of the platinum nanoparticles of the elongated shape
are equivalent to the formulas previously given for spherical particles, if the particle length
and its diameter are equal. In this case, patterns for symmetric particles and more general
(modified) patterns can be used interchangeably.
Practical implications: Development of new and more effective catalysts for fuel cells.
Originality/value: The significance of the presented work results from the possibility
of using the described method in the catalyst studies during real catalytic processes.
It allows comparing catalytic activity after the process, also in unusual conditions and in an
aggressive environment, using minimal amounts of material
Growth Rate and Morphology of a Single Calcium Carbonate Crystal on Polysulfone Film Measured with Time Lapse Raman Micro Spectroscopy
The growth of single, self- nucleated calcium carbonate crystals on a polysulfone (PSU) film was investigated with high resolution, time lapse Raman imaging. The Raman images were acquired on the interface of the polymer with the crystal. The growth of crystals could thus be followed in time. PSU is a polymer that is used as a membrane material in water cleaning technology. The intensity of the Raman band at the position of 1086 cm-1, which is due to the symmetric stretching of the C-O bonds in the carbonate group of calcite was used to translate the number of CO3 2- ions in a crystal to the growth in time. The growth rate of single crystals of calcium carbonate on a surface was obtained from successive Raman images. We are presenting for the first time time-lapse Raman images of single crystal growth as a direct method to determine a crystal growth rate on an industrially relevant membrane material, like polysulfone
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