Deformation behaviour of paper and board subjected to moisture diffusion

AbstractThis paper presents a method to predict the through-thickness moisture content distribution and associated induced deformations of paper and cardboard sheets as they are subjected to relative humidity changes. The transient moisture diffusion problem is solved using a “natural” analytic approach that has previously been applied for solving transient heat conduction in multi-layer solids. The deformation behaviour of the sheet during the moisture diffusion process is predicted using a semi-analytical approach based on a Rayleigh–Ritz minimization of the total potential energy. Geometrically nonlinear effects are taken into account. Curvatures of the originally flat sheet are predicted as a function of time, as are the shapes of the sheet for steady-state condition. As multiple solutions exist, stability is studied. The developed model was used to study the deformation behaviour of one paper and two cardboard sheets. Comparisons with finite-element results demonstrate that the developed model provides accurate results. The displacements obtained for steady-state conditions are within +6%. Comparisons with previous steady-state analyses reveal important differences in the shape of one cardboard sheet. This suggests that the moisture diffusion process may influence the configuration assumed by the sheet at steady-state equilibrium. Hence, it may be necessary to take the moisture diffusion into account in the analysis to accurately predict the hygro-mechanical behaviour of paper or cardboard sheets

Étude des déformations hygromécaniques dans des feuilles de papier multicouches

Ce mémoire présente des travaux de recherche portant sur les déformations hygromécaniques en régime transitoire d'une feuille de papier multicouche. Un modèle semi-analytique permettant de prédire ces déformations a été développé. Ce modèle utilise la théorie de la diffusion de l'humidité en régime transitoire à travers une plaque multicouche combinée à la théorie classique des stratifiés modifiée pour tenir compte des non linéarités géométriques. Les résultats du modèle pour une feuille de papier multicouche et pour deux types de carton ont été comparés aux résultats d'un modèle d'éléments finis. Le modèle semi-analytique développé a permis d'obtenir des résultats similaires aux résultats du modèle d'éléments finis, tout en minimisant le temps de calcul requis. Une étude expérimentale a ensuite été menée afin de valider les prédictions du modèle. Différentes couches de papier ont été utilisées pour concevoir des assemblages multicouches. Toutes les propriétés des couches individuelles et des assemblages requises par le modèle ont été évaluées. Enfin, les assemblages conçus ont été esposés à différents cycles d'humidité afin d'étudier leurs déformations hygromécaniques. Un système de mesure des déplacements en 3D a été utilisé pour mesurer les courbures des assemblages en fonction du temps. Les résultats des essais expérimentaux montrent une assez bonne concordance avec les prédictions du modèle semi-analytique, mais le temps requis pour atteindre l'équilibre est beaucoup plus long que prévu

Mesures de la croissance de la productivité dans un cadre d'équilibre général : L'économie du Québec entre 1978 et 1984

We propose a new measure of total factor productivity (TFP) growth in a general equilibrium setting.It measures by how much the efficiency frontier moves outwards given the availability of primary ressources, the technology and the structure of domestic final demand. Prices are endogenous. We apply this new measure to the Québec economy between 1978 and 1984. We find negative TFP growth rates in most of the manufacturing industries and positive and relatively high growth rates in the service sectors. Aggregate annual TFP growth was 1.1% over this period. Nous proposons une nouvelle mesure de la croissance de la productivité totale des facteurs (PTF) issue d'un modèle d'équilibre général. Elle mesure le déplacement de la frontière d'efficacité d'une économie, étant donné ses ressources primaires, sa balance commerciale, sa technologie et la structure de sa demande finale domestique. Les prix sont endogènes. Nous appliquons cette nouvelle mesure à l'économie du Québec entre 1978 et 1984. Nous obtenons des taux de croissance de la PTF négatifs dans la plupart des industries manufacturières et des taux positifs et relativement élevés pour plusieurs industries du tertiaire. Le taux de croissance annuel agrégé de la PTF fut de 1,1% pour cette période.Productivity, General Competitive Equilibrium, Québec,

Les représentations sociales du travail dans des parcours de retour aux études aux niveaux collégial et universitaire

Cet article porte sur le volet éducatif de la production et de la reproduction de la main-d’œuvre hautement qualifiée par l’examen des processus en jeu au moment des retours aux études dans des programmes de formation technique et de génie. Nous nous intéressons en particulier à une situation emblématique des référentiels politiques récents en matière d’éducation, soit les retours aux études. Nous cherchons à mieux comprendre comment le retour aux études se réalise, comment les représentations professionnelles agissent sur ce dernier et comment l’expérience scolaire influence les projets des individus. Notre analyse met l’accent sur les ressorts sociaux et culturels des décisions relatives au choix de programmes et à l’orientation professionnelle d’étudiants qui ont interrompu leurs études et qui y retournent. Nous explorons le discours d’étudiants et d’étudiantes qui ont choisi de profiter de la souplesse du système d’éducation québécois pour compléter ou bonifier leur formation initiale ou encore pour tenter une réorientation professionnelle. En particulier, nous désirons savoir comment les différentes formes d’articulation entre éducation et travail influencent les représentations sociales des étudiants au sujet des titres scolaires, de l’évolution de leur carrière scolaire et de leur projet professionnel personnel.This paper deals with the educational aspect of the production and reproduction of highly qualified manpower through examining the processes at play when people return to school by enrolling in technical or engineering training programs. Our interest is focussed specifically on returning to school as an emblematic situation in recent educational policy frameworks. We are trying to better understand how school return is done, how professional representations act upon it and how previous school experience influences individual projects. Our analysis focuses on the social and cultural factors involved in decisions on program choices and professional orientation made by students who return to school after an interruption. We analyse the discourse of male and female students who have chosen to take advantage of the flexibility of the Quebec educational system in order to complete or improve on their initial education or to attempt a career change. More specifically, we want to know how various forms of articulation between formal training and work influence students’ social representations of university degrees, the evolution of their own school career and individual professional projects

Guide to the software engineering body of knowledge

0 7 4 0 -7 4 5 9 / 9 9 / $ 1 0 . 0 0 © 1 9 9 9 I E E E N o v e m b e r / D e c e m b e r 1 9 9 9 I E E E S o f t w a r e 3 5 he IEEE Computer Society and the Association for Computing Machinery are working on a joint project to develop a guide to the Software Engineering Body of Knowledge (SWEBOK). Articulating a body of knowledge is an essential step toward developing a profession because it represents a broad consensus regarding the contents of the discipline. Without such a consensus, there is no way to validate a licensing examination, set a curriculum to prepare individuals for the examination, or formulate criteria for accrediting the curriculum. The SWEBOK project (http://www.swebok.org) is now nearing the end of the second of its three phases. Here we summarize the results to date and provide an overview of the project and its status. The Guide to the Software Engineering Body of Knowledge Repor ting on the SWEBOK project, the authors-who represent the project's editorial team-discuss the three-phase plan to characterize a body of knowledge, a vital step toward developing soft ware engineering as a profession.

Optimization of temporal versus spatial replication in the development of habitat use models to explain among-reach variations of fish density estimates in rivers

Abstract: We evaluated the effects of temporal variation of fish density estimates on the explanatory power of habitat use models. Fish density estimates were obtained using visual surveys (10 visits) in eighteen 100 m reaches over a 7-week period. Physical attributes of reaches were estimated. Field data were used to develop a simulation domain (10 000 reaches) that reflected the spatio-temporal variability of fish density estimates and physical attributes. Simulations indicated that for a sampling effort of approximately 200 surveys, the number of reaches surveyed (25 to 200) and the number of surveys per reach (1 to 8) affected the adjusted R 2 of models by 5% to 42%. The established practice of sampling a maximized number of reaches once did not appear necessarily optimal for developing habitat use models. Analysis of temporal coefficients of variation suggests that species within the same family may require a similar survey design. Hence, for salmonids, it may be more appropriate to sample more reaches once, and for cyprinids, it may be more optimal to repeatedly sample fewer reaches

Exome-wide association study to identify rare variants influencing COVID-19 outcomes : Results from the Host Genetics Initiative

Publisher Copyright: Copyright: © 2022 Butler-Laporte et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Host genetics is a key determinant of COVID-19 outcomes. Previously, the COVID-19 Host Genetics Initiative genome-wide association study used common variants to identify multiple loci associated with COVID-19 outcomes. However, variants with the largest impact on COVID-19 outcomes are expected to be rare in the population. Hence, studying rare variants may provide additional insights into disease susceptibility and pathogenesis, thereby informing therapeutics development. Here, we combined whole-exome and whole-genome sequencing from 21 cohorts across 12 countries and performed rare variant exome-wide burden analyses for COVID-19 outcomes. In an analysis of 5,085 severe disease cases and 571,737 controls, we observed that carrying a rare deleterious variant in the SARS-CoV-2 sensor toll-like receptor TLR7 (on chromosome X) was associated with a 5.3-fold increase in severe disease (95% CI: 2.75–10.05, p = 5.41x10-7). This association was consistent across sexes. These results further support TLR7 as a genetic determinant of severe disease and suggest that larger studies on rare variants influencing COVID-19 outcomes could provide additional insights.Peer reviewe

From Sea to Sea: Canada's Three Oceans of Biodiversity

Evaluating and understanding biodiversity in marine ecosystems are both necessary and challenging for conservation. This paper compiles and summarizes current knowledge of the diversity of marine taxa in Canada's three oceans while recognizing that this compilation is incomplete and will change in the future. That Canada has the longest coastline in the world and incorporates distinctly different biogeographic provinces and ecoregions (e.g., temperate through ice-covered areas) constrains this analysis. The taxonomic groups presented here include microbes, phytoplankton, macroalgae, zooplankton, benthic infauna, fishes, and marine mammals. The minimum number of species or taxa compiled here is 15,988 for the three Canadian oceans. However, this number clearly underestimates in several ways the total number of taxa present. First, there are significant gaps in the published literature. Second, the diversity of many habitats has not been compiled for all taxonomic groups (e.g., intertidal rocky shores, deep sea), and data compilations are based on short-term, directed research programs or longer-term monitoring activities with limited spatial resolution. Third, the biodiversity of large organisms is well known, but this is not true of smaller organisms. Finally, the greatest constraint on this summary is the willingness and capacity of those who collected the data to make it available to those interested in biodiversity meta-analyses. Confirmation of identities and intercomparison of studies are also constrained by the disturbing rate of decline in the number of taxonomists and systematists specializing on marine taxa in Canada. This decline is mostly the result of retirements of current specialists and to a lack of training and employment opportunities for new ones. Considering the difficulties encountered in compiling an overview of biogeographic data and the diversity of species or taxa in Canada's three oceans, this synthesis is intended to serve as a biodiversity baseline for a new program on marine biodiversity, the Canadian Healthy Ocean Network. A major effort needs to be undertaken to establish a complete baseline of Canadian marine biodiversity of all taxonomic groups, especially if we are to understand and conserve this part of Canada's natural heritage