Lift-up Hysteresis Butterflies in Friction

Charles-Augustin de Coulomb postulated that the act of rubbing of surfaces against each other leads the asperities on the surfaces to deform and mount each other. Thus, in order for tangential motion to ensue, an associated lift-up in the direction normal to the surface, will take place. Although this behavior has been sporadically pointed out in literature, we believe that the butterfly curves associated with it during presliding have not been reported before. We have performed dry, presliding rubbing experiments that show that there is a regular, relative normal displacement associated with the tangential motion; in particular, that normal motion describes rate-independent, hysteresis, butterfly curves (similar in nature to those found in piezo-electric and magnetic materials), in the tangential displacement and in the tangential force, respectively. This communication outlines and explores the basic behavior of those butterfly curves experimentally.     

Toward the inclusion of end-to-end security in the OM2M platform

The Journal of Supercomputing - The exponential growth in the number of Internet of things (IoT) devices and their potential in many applications in a vast number of domains fuelled the development...     

Combinatorial materials research applied to the development of new surface coatings VI: An automated spinning water jet apparatus for the high-throughput characterization of fouling-release marine coatings

Large numbers of coatings can be generated very quickly using a combinatorial high-throughput approach. Rapid screening assays are typically required to adequately evaluate and down select coating candidates to identify promising compositions. An automated, spinning water jet apparatus was developed to rapidly characterize the adhesion strength of marine organisms to coating surfaces. Coating arrays are cast in multiwell plates and subjected to a jet of water of controlled pressure and duration. Array plates are manipulated by a robotic arm to facilitate accurate and repeatable water jet treatments. Jet pressures of 40-688 kPa can be generated and precisely maintained by computer control. A five axis robotic arm selects plates from three plate stacking hotels yielding a total of 39 plates or 936 individual coating samples for each experimental run. All robotic instructions, process parameters, and data are stored and controlled by the computer. The large plate handling capacity offered by the robotic system enables the analysis of a wide variety of coatings for "fouling-release" properties. A brief example demonstrating the capability of the automated water jet apparatus to evaluate marine bacterial adhesion to coating surfaces is provided.     

Dissolved Silicon and Its Origin in Belgian Beers—A Multivariate Analysis

Beer is a quintessential part of Belgian heritage. We performed a detailed analysis of factors controlling Si content in Belgian beers as a case study to coincide with the 2011 IBiS meeting in Antwerp (Belgium). Beer is one of the richest dietary sources of Si. Three decades of research have yielded evidence of a role for Si in human physiology: it plays an essential role in bone mineral density and reduces the biological availability of aluminium. We analysed 119 Belgian beers: highest dissolved Si concentrations were found in high fermentation, traditionally brewed ales. Concentrations ranged between 214 and 2,071 μmol L^???1. This is probably due to the complexity and length of the brewing procedure: longer, more complicated processing and presence of brewing sediment in the bottle allows more Si to dissolve out of the base products like hop, barley or even rice. As a side effect of fermentation, alcohol content was related to Si content.     

Attention to instruction directed to another by U.S. Mexican-heritage children of varying cultural backgrounds.

Children commonly observe and pitch in to ongoing activities in Indigenous communities of Mexico, according to ethnographic research. The present study examines the generality of this approach to learning by comparing its use among Mexican immigrants of two cultural backgrounds in the United States. Results showed more sustained attention to (and learning from) instruction directed to another person by 22 U.S. Mexican-heritage 6- to 11-year-old children whose families likely have experience with Indigenous practices (and limited involvement in Western schooling), compared with 16 U.S. Mexican-heritage children whose families have extensive involvement in Western schooling (and related practices). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetic studies of cationic photopolymerizations of cycloaliphatic epoxide,triethyleneglycol methyl vinyl ether,and cyclohexene oxide

The cationic photopolymerizations of monofunctional monomers and cycloaliphatic diepoxide monomer were examined in detail. Phenomenological kinetic models were developed for photopolymerizations of the monofunctional and difunctional monomers. For monofunctional monomers, the nonlinear models gave an excellent fit to the experimental data. Although a second‐order autocatalytic model was shown to be invalid above 10% conversion for the polymerization of a difunctional monomer (3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate, ECH), an autocatalytic model using diffusion‐controlled reaction with a Williams‐Landel‐Ferry (WLF) equation fits the experimental data well over the entire conversion range. A mechanistic model based on the free volume theory was also developed for cationic polymerization of the cycloaliphatic di‐epoxide monomer by using the method of moments. The model gives a good fit for the conversion and M_w development, but the calculated M_n results are lower than the experimental values. POLYM. ENG. SCI., 45:1546–1555, 2005. © 2005 Society of Plastics Engineers     

A Course in Technology and Society for Engineering Students

The exposure of engineering students to relationships between technology and society has become an accepted component of undergraduate engineering curricula in North America, yet how to present the subject in a way that is stimulating and relevant to engineering students remains a challenge. At the University of Manitoba, various approaches have been taken over several years. This paper outlines a course format and content which has been well received by students. The framework of the course encompasses three main principles. First, technology is presented as having three aspects—technical, cultural, and organizational. Second, the topic is treated within a time-related context—past, present, and future. Past and present are illustrated by examples of technology, their societal impacts, and related cultural and ethical issues. The future is examined using a systems approach for understanding the long-term consequences of human activities and by discussion of the role of technology in reaching global sustainability. Third, the course emphasizes active student involvement through individual and group research and writing, and group discussions and presentation.