École Polytechnique de Montréal

About: École Polytechnique de Montréal is a education organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Finite element method & Computer science. The organization has 8015 authors who have published 18390 publications receiving 494372 citations.

Comparison of three computer office workstations offering forearm support: impact on upper limb posture and muscle activation.

Abstract: The aims of the study were: 1) to determine whether resting the forearms on the work surface, as compared to chair armrests, reduces muscular activation; 2) to compare the sensitivity of different electromyographic (EMG) summary parameters. Eighteen healthy subjects performed computer work (with keyboard and mouse alternately) for 20 min while resting their forearms on a work surface adjustable in height (Workstation A), on the chair's armrests with an adjustable workstation (Workstation B) or on their chair's armrests with a non-adjustable workstation (Workstation C). The EMG amplitude of the trapezius and deltoid muscles was little influenced by the workstations, whereas their EMG variability increased with Workstation A, which was interpreted as a positive effect. However, the EMG amplitude of the mouse-side extensor digitorum muscle was higher with Workstation A. Alternating between resting the forearms on the work surface and on the chairs' armrests could solicit different muscles during computer work, and could be considered as a strategy for preventing musculoskeletal disorders. The new exposure variation analysis summary parameters used were sensitive to small workstation changes, thus supporting their use in future studies.

Code siblings: Technical and legal implications of copying code between applications

Abstract: Source code cloning does not happen within a single system only. It can also occur between one system and another. We use the term code sibling to refer to a code clone that evolves in a different system than the code from which it originates. Code siblings can only occur when the source code copyright owner allows it and when the conditions imposed by such license are not incompatible with the license of the destination system. In some situations copying of source code fragments are allowed—legally—in one direction, but not in the other. In this paper, we use clone detection, license mining and classification, and change history techniques to understand how code siblings—under different licenses—flow in one direction or the other between Linux and two BSD Unixes, FreeBSD and OpenBSD. Our results show that, in most cases, this migration appears to happen according to the terms of the license of the original code being copied, favoring always copying from less restrictive licenses towards more restrictive ones. We also discovered that sometimes code is inserted to the kernels from an outside source.

Metalorganic vapor phase epitaxy of coherent self-assembled InAs nanometer-sized islands in InP(001)

Abstract: The metalorganic vapor phase epitaxy of coherent self-assembled InAs islands on InP(001) is demonstrated. Samples are characterized using transmission electron microscopy and photoluminescence (PL) spectroscopy at 77 K. The deposition of ∼2.4–4.8 monolayers (ML) of InAs at 500°C followed by a 30 s growth interruption results in the formation of coherent islands whose average diameter is 30–35 nm with a standard deviation of 8 nm and whose areal density is (3–4)×1010 cm−2. The PL emission is centered at 0.79 eV and has a full width at half maximum (FWHM) of 90 meV. When the nominal deposited thickness is increased to ∼9.6 ML, the average island diameter increases to ∼120 nm while the areal density decreases to ∼109 cm−2. The resulting PL is then centered at 0.83 eV with a FWHM of 130 meV and also displays a peak at 1.23 eV which is attributed to an InAs wetting layer ∼2 ML in thickness.

Solid particle erosion mechanisms of protective coatings for aerospace applications

Abstract: The design of the appropriate material system for a given tribological application must be guided by an accurate understanding of the degradation mechanisms and the surface response to loading and deformation. In this review article, a detailed overview of the material loss mechanisms during solid particle erosion (SPE) which occurs when hard particles are entrained by an air flow and impact exposed surfaces will be presented. In the first part of the paper, several methodological considerations essential for the assessment of multi-parameter correlations necessary for the accurate interpretation of SPE data will be discussed. Then, the ductile and brittle SPE mechanisms, the transitions between these different material removal processes and the effect of particle properties on overall erosion behavior will be examined. Finally, in the last section of the paper, the various coating material systems proposed in the literature for protection against SPE are reviewed with a focus on the two main categories of TiN-based and carbon-based coatings. Concluding this review is a discussion on the effects of coating system microstructure and architecture on the SPE mechanisms of vapor deposited coatings. It will be shown that to significantly impact the future technological development of SPE protective coatings, novel highly resolved characterization methodologies need to be developed and employed.